Sensors

18 pages, 479 KiB

Open AccessArticle

Hand Motion Classification Using a Multi-Channel Surface Electromyography Sensor

by Xueyan Tang^1,*, Yunhui Liu¹, Congyi Lv¹ and Dong Sun²

¹ Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong

² Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong

Sensors 2012, 12(2), 1130-1147; https://doi.org/10.3390/s120201130 - 30 Jan 2012

Cited by 81 | Viewed by 11406

Abstract

The human hand has multiple degrees of freedom (DOF) for achieving high-dexterity motions. Identifying and replicating human hand motions are necessary to perform precise and delicate operations in many applications, such as haptic applications. Surface electromyography (sEMG) sensors are a low-cost method for [...] Read more.

The human hand has multiple degrees of freedom (DOF) for achieving high-dexterity motions. Identifying and replicating human hand motions are necessary to perform precise and delicate operations in many applications, such as haptic applications. Surface electromyography (sEMG) sensors are a low-cost method for identifying hand motions, in addition to the conventional methods that use data gloves and vision detection. The identification of multiple hand motions is challenging because the error rate typically increases significantly with the addition of more hand motions. Thus, the current study proposes two new methods for feature extraction to solve the problem above. The first method is the extraction of the energy ratio features in the time-domain, which are robust and invariant to motion forces and speeds for the same gesture. The second method is the extraction of the concordance correlation features that describe the relationship between every two channels of the multi-channel sEMG sensor system. The concordance correlation features of a multi-channel sEMG sensor system were shown to provide a vast amount of useful information for identification. Furthermore, a new cascaded-structure classifier is also proposed, in which 11 types of hand gestures can be identified accurately using the newly defined features. Experimental results show that the success rate for the identification of the 11 gestures is significantly high. Full article

(This article belongs to the Special Issue Control Systems and Robotics in Bioengineering)

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22 pages, 5037 KiB

Open AccessArticle

Complete Vision-Based Traffic Sign Recognition Supported by an I2V Communication System

by Miguel A. García-Garrido^1,*, Manuel Ocaña¹

, David F. Llorca², Estefanía Arroyo¹, Jorge Pozuelo¹ and Miguel Gavilán²

¹ Electronics Department, Polytechnic School, University of Alcalá, Madrid 28871, Spain

² Computer Engineering Department, Polytechnic School, University of Alcalá, Madrid 28871, Spain

Sensors 2012, 12(2), 1148-1169; https://doi.org/10.3390/s120201148 - 30 Jan 2012

Cited by 31 | Viewed by 15711

Abstract

This paper presents a complete traffic sign recognition system based on vision sensor onboard a moving vehicle which detects and recognizes up to one hundred of the most important road signs, including circular and triangular signs. A restricted Hough transform is used as [...] Read more.

This paper presents a complete traffic sign recognition system based on vision sensor onboard a moving vehicle which detects and recognizes up to one hundred of the most important road signs, including circular and triangular signs. A restricted Hough transform is used as detection method from the information extracted in contour images, while the proposed recognition system is based on Support Vector Machines (SVM). A novel solution to the problem of discarding detected signs that do not pertain to the host road is proposed. For that purpose infrastructure-to-vehicle (I2V) communication and a stereo vision sensor are used. Furthermore, the outputs provided by the vision sensor and the data supplied by the CAN Bus and a GPS sensor are combined to obtain the global position of the detected traffic signs, which is used to identify a traffic sign in the I2V communication. This paper presents plenty of tests in real driving conditions, both day and night, in which an average detection rate over 95% and an average recognition rate around 93% were obtained with an average runtime of 35 ms that allows real-time performance. Full article

(This article belongs to the Section Physical Sensors)

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Graphical abstract

11 pages, 318 KiB

Open AccessArticle

The Electromechanical Behavior of a Micro-Ring Driven by Traveling Electrostatic Force

by Xiuqian Ye¹, Yibao Chen¹, Da-Chih Chen², Kuo-Yi Huang³ and Yuh-Chung Hu^2,*

¹ School of Electromechanical Automobile Engineering, Yantai University, 32 Qingquan Road, Yantai 264005, China

² Department of Mechanical and Electromechanical Engineering, National ILan University, 1 Section, Shen-Lung Road, ILan 260, Taiwan

³ Department of Bio-Industrial Mechatronics Engineering, National Chung Hsing University, 150 Kuo Kuang Road, Taichung 402, Taiwan

Sensors 2012, 12(2), 1170-1180; https://doi.org/10.3390/s120201170 - 30 Jan 2012

Cited by 14 | Viewed by 6670

Abstract

There is no literature mentioning the electromechanical behavior of micro structures driven by traveling electrostatic forces. This article is thus the first to present the dynamics and stabilities of a micro-ring subjected to a traveling electrostatic force. The traveling electrostatic force may be [...] Read more.

There is no literature mentioning the electromechanical behavior of micro structures driven by traveling electrostatic forces. This article is thus the first to present the dynamics and stabilities of a micro-ring subjected to a traveling electrostatic force. The traveling electrostatic force may be induced by sequentially actuated electrodes which are arranged around the flexible micro-ring. The analysis is based on a linearized distributed model considering the electromechanical coupling effects between electrostatic force and structure. The micro-ring will resonate when the traveling speeds of the electrostatic force approach some critical speeds. The critical speeds are equal to the ratio of the natural frequencies to the wave number of the correlative natural mode of the ring. Apart from resonance, the ring may be unstable at some unstable traveling speeds. The unstable regions appear not only near the critical speeds, but also near some fractions of some critical speeds differences. Furthermore the unstable regions expand with increasing driving voltage. This article may lead to a new research branch on electrostatic-driven micro devices. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 366 KiB

Open AccessReview

Applications of Aptasensors in Clinical Diagnostics

by Ping Hong^1,2, Wenli Li^1,2 and Jinming Li^1,2,*

¹ National Center for Clinical Laboratories, Beijing Hospital, Beijing 100730, China

² Graduate School, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China

Sensors 2012, 12(2), 1181-1193; https://doi.org/10.3390/s120201181 - 30 Jan 2012

Cited by 154 | Viewed by 12849

Abstract

Aptamers are artificial oligonucleotides (DNA or RNA) selected in vitro that bind a broad range of targets with high affinity and specificity; a sensitive yet simple method to utilize aptamers as recognition elements for the development of biosensors (aptasensors) is to transduce the [...] Read more.

Aptamers are artificial oligonucleotides (DNA or RNA) selected in vitro that bind a broad range of targets with high affinity and specificity; a sensitive yet simple method to utilize aptamers as recognition elements for the development of biosensors (aptasensors) is to transduce the signal electrochemically. So far, aptasensors have been applied to clinical diagnostics and several technologies are in development. Aptasensors will extend the limits of current clinical diagnostics. Although the potential diagnostic applications are unlimited, the most current applications are foreseen in the areas of biomarker detection, cancer clinical testing, detection of infectious microorganisms and viruses. This review attempts to list examples of the research progresses of aptamers in biosensor platforms that have been published in recent years; in particular, we display cases of aptasensors that are already incorporated in clinical diagnostics or have potential applications in clinical diagnostics. Full article

(This article belongs to the Special Issue Aptamer-Based Sensors)

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17 pages, 628 KiB

Open AccessArticle

Enhancing the Reliability of Head Nodes in Underwater Sensor Networks

by Hong Min¹, Yookun Cho¹ and Junyoung Heo^2,*

¹ School of Computer Science and Engineering, Seoul National University, Seoul 151-742, Korea

² Department of Computer Engineering, Hansung University, Seoul 151-742, Korea

Sensors 2012, 12(2), 1194-1210; https://doi.org/10.3390/s120201194 - 31 Jan 2012

Cited by 16 | Viewed by 8556

Abstract

Underwater environments are quite different from terrestrial environments in terms of the communication media and operating conditions associated with those environments. In underwater sensor networks, the probability of node failure is high because sensor nodes are deployed in harsher environments than ground-based networks. [...] Read more.

Underwater environments are quite different from terrestrial environments in terms of the communication media and operating conditions associated with those environments. In underwater sensor networks, the probability of node failure is high because sensor nodes are deployed in harsher environments than ground-based networks. The sensor nodes are surrounded by salt water and moved around by waves and currents. Many studies have focused on underwater communication environments in an effort to improve the data transmission throughput. In this paper, we present a checkpointing scheme for the head nodes to quickly recover from a head node failure. Experimental results show that the proposed scheme enhances the reliability of the networks and makes them more efficient in terms of energy consumption and the recovery latency compared to the previous scheme without checkpointing. Full article

(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks)

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69 pages, 1186 KiB

Open AccessReview

Brain Computer Interfaces, a Review

by Luis Fernando Nicolas-Alonso^* and Jaime Gomez-Gil

Department of Signal Theory, Communications and Telematics Engineering, University of Valladolid, Valladolid 47011, Spain

Sensors 2012, 12(2), 1211-1279; https://doi.org/10.3390/s120201211 - 31 Jan 2012

Cited by 1762 | Viewed by 76656

Abstract

A brain-computer interface (BCI) is a hardware and software communications system that permits cerebral activity alone to control computers or external devices. The immediate goal of BCI research is to provide communications capabilities to severely disabled people who are totally paralyzed or ‘locked [...] Read more.

A brain-computer interface (BCI) is a hardware and software communications system that permits cerebral activity alone to control computers or external devices. The immediate goal of BCI research is to provide communications capabilities to severely disabled people who are totally paralyzed or ‘locked in’ by neurological neuromuscular disorders, such as amyotrophic lateral sclerosis, brain stem stroke, or spinal cord injury. Here, we review the state-of-the-art of BCIs, looking at the different steps that form a standard BCI: signal acquisition, preprocessing or signal enhancement, feature extraction, classification and the control interface. We discuss their advantages, drawbacks, and latest advances, and we survey the numerous technologies reported in the scientific literature to design each step of a BCI. First, the review examines the neuroimaging modalities used in the signal acquisition step, each of which monitors a different functional brain activity such as electrical, magnetic or metabolic activity. Second, the review discusses different electrophysiological control signals that determine user intentions, which can be detected in brain activity. Third, the review includes some techniques used in the signal enhancement step to deal with the artifacts in the control signals and improve the performance. Fourth, the review studies some mathematic algorithms used in the feature extraction and classification steps which translate the information in the control signals into commands that operate a computer or other device. Finally, the review provides an overview of various BCI applications that control a range of devices. Full article

(This article belongs to the Special Issue Collaborative Sensors)

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8 pages, 427 KiB

Open AccessArticle

Enhanced Responsivity of Photodetectors Realized via Impact Ionization

by Ji Yu^1,2, Chong-Xin Shan^1,*, Qian Qiao^1,2, Xiu-Hua Xie^1,2, Shuang-Peng Wang¹, Zhen-Zhong Zhang¹ and De-Zhen Shen¹

¹ State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China

² Graduate University of the Chinese Academy of Sciences, Beijing 100049, China

Sensors 2012, 12(2), 1280-1287; https://doi.org/10.3390/s120201280 - 31 Jan 2012

Cited by 28 | Viewed by 9097

Abstract

To increase the responsivity is one of the vital issues for a photodetector. By employing ZnO as a representative material of ultraviolet photodetectors and Si as a representative material of visible photodetectors, an impact ionization process, in which additional carriers can be generated [...] Read more.

To increase the responsivity is one of the vital issues for a photodetector. By employing ZnO as a representative material of ultraviolet photodetectors and Si as a representative material of visible photodetectors, an impact ionization process, in which additional carriers can be generated in an insulating layer at a relatively large electric field, has been employed to increase the responsivity of a semiconductor photodetector. It is found that the responsivity of the photodetectors can be enhanced by tens of times via this impact ionization process. The results reported in this paper provide a general route to enhance the responsivity of a photodetector, thus may represent a step towards high-performance photodetectors. Full article

(This article belongs to the Section Physical Sensors)

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11 pages, 859 KiB

Open AccessArticle

A Compact Inductive Position Sensor Made by Inkjet Printing Technology on a Flexible Substrate

by Nikola Jeranče, Dragana Vasiljević, Nataša Samardžić and Goran Stojanović^*

Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovića 6, Novi Sad 21000, Serbia

Sensors 2012, 12(2), 1288-1298; https://doi.org/10.3390/s120201288 - 31 Jan 2012

Cited by 28 | Viewed by 7763

Abstract

This paper describes the design, simulation and fabrication of an inductive angular position sensor on a flexible substrate. The sensor is composed of meandering silver coils printed on a flexible substrate (Kapton film) using inkjet technology. The flexibility enables that after printing in [...] Read more.

This paper describes the design, simulation and fabrication of an inductive angular position sensor on a flexible substrate. The sensor is composed of meandering silver coils printed on a flexible substrate (Kapton film) using inkjet technology. The flexibility enables that after printing in the plane, the coils could be rolled and put inside each other. By changing the angular position of the internal coil (rotor) related to the external one (stator), the mutual inductance is changed and consequently the impedance. It is possible to determine the angular position from the measured real and imaginary part of the impedance, in our case in the frequency range from 1 MHz to 10 MHz. Experimental results were compared with simulation results obtained by in-house developed software tool, and very good agreement has been achieved. Thanks to the simple design and fabrication, smaller package space requirements and weight, the presented sensor represents a cost-effective alternative to the other sensors currently used in series production applications. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 1626 KiB

Open AccessArticle

Development of a Low-Cost Airborne Ultrasound Sensor for the Detection of Brick Joints behind a Wall Painting

by Fernando-Juan García-Diego^1,2,*

, José María Bravo^1,2, Juan Pérez-Miralles^3,4, Héctor Estrada^2,5 and Angel Fernández-Navajas¹

¹ Departamento de Física Aplicada, Universidad Politécnica de Valencia, Av. de los Naranjos s/n, Valencia 46022, Spain

² Centro de Tecnologías Físicas, Unidad Asociada ICMM-CSIC/UPV, Universidad Politécnica de Valencia, Av. de los Naranjos s/n, Valencia 46022, Spain

³ Servicio de Conservación y Restauración de la Exma, Diputación de Castellón (SCRC), Complejo Socio-Educativo de Penyeta Roja s/n, Castellón 12080, Spain

⁴ Instituto Valenciano de Conservación y Restauración de Bienes Culturales (IVC+R), Complejo Socio-Educativo de Penyeta Roja s/n, Castellón 12080, Spain

⁵ Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, Madrid 28049, Spain

Sensors 2012, 12(2), 1299-1311; https://doi.org/10.3390/s120201299 - 31 Jan 2012

Cited by 14 | Viewed by 8529

Abstract

Non-destructive methods are of great interest for the analysis of cultural heritage. Among the different possible techniques, this paper presents a low cost prototype based on the emission and reception of airborne ultrasound without direct contact with the test specimen. We successfully performed [...] Read more.

Non-destructive methods are of great interest for the analysis of cultural heritage. Among the different possible techniques, this paper presents a low cost prototype based on the emission and reception of airborne ultrasound without direct contact with the test specimen. We successfully performed a method test for the detection of brick joints under a XVth century Renaissance fresco of the Metropolitan Cathedral of the city of Valencia (Spain). Both laboratory and in situ results are in agreement. Using this prototype system, an early moisture detection system has been installed in the dome that supports the fresco. The result is encouraging and opens interesting prospects for future research. Full article

(This article belongs to the Section Physical Sensors)

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24 pages, 1373 KiB

Open AccessArticle

Underwater Wireless Sensor Networks: How Do Acoustic Propagation Models Impact the Performance of Higher-Level Protocols?

by Jesús Llor^* and Manuel P. Malumbres

Physics and Computer Engineering Department, Miguel Hernandez University, Ave. Universidad S/N, Ed. Alcudia, 03202 Elche (Alicante), Spain

Sensors 2012, 12(2), 1312-1335; https://doi.org/10.3390/s120201312 - 31 Jan 2012

Cited by 42 | Viewed by 9893

Abstract

Several Medium Access Control (MAC) and routing protocols have been developed in the last years for Underwater Wireless Sensor Networks (UWSNs). One of the main difficulties to compare and validate the performance of different proposals is the lack of a common standard to [...] Read more.

Several Medium Access Control (MAC) and routing protocols have been developed in the last years for Underwater Wireless Sensor Networks (UWSNs). One of the main difficulties to compare and validate the performance of different proposals is the lack of a common standard to model the acoustic propagation in the underwater environment. In this paper we analyze the evolution of underwater acoustic prediction models from a simple approach to more detailed and accurate models. Then, different high layer network protocols are tested with different acoustic propagation models in order to determine the influence of environmental parameters on the obtained results. After several experiments, we can conclude that higher-level protocols are sensitive to both: (a) physical layer parameters related to the network scenario and (b) the acoustic propagation model. Conditions like ocean surface activity, scenario location, bathymetry or floor sediment composition, may change the signal propagation behavior. So, when designing network architectures for UWSNs, the role of the physical layer should be seriously taken into account in order to assert that the obtained simulation results will be close to the ones obtained in real network scenarios. Full article

(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks)

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16 pages, 2883 KiB

Open AccessArticle

A Radar-Enabled Collaborative Sensor Network Integrating COTS Technology for Surveillance and Tracking

by Robert Kozma^1,*, Lan Wang¹, Khan Iftekharuddin², Ernest McCracken¹, Muhammad Khan¹, Khandakar Islam¹, Sushil R. Bhurtel¹ and R. Murat Demirer³

¹ Center for Large-Scale Integrated Optimization & Networks (CLION), FedEx Institute of Technology, University of Memphis, 365 Innovation Drive, Memphis, TN 38152, USA

² Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23529, USA

³ Computer Engineering Department, Istanbul Kultur University, E5 Atakoy Campus E5 Otoyolu Londra Asfalt, Bakrkoy, 34156 Istanbul, Turkey

Sensors 2012, 12(2), 1336-1351; https://doi.org/10.3390/s120201336 - 31 Jan 2012

Cited by 12 | Viewed by 9787

Abstract

The feasibility of using Commercial Off-The-Shelf (COTS) sensor nodes is studied in a distributed network, aiming at dynamic surveillance and tracking of ground targets. Data acquisition by low-cost ( [...] Read more.

The feasibility of using Commercial Off-The-Shelf (COTS) sensor nodes is studied in a distributed network, aiming at dynamic surveillance and tracking of ground targets. Data acquisition by low-cost ( < $50 US) miniature low-power radar through a wireless mote is described. We demonstrate the detection, ranging and velocity estimation, classification and tracking capabilities of the mini-radar, and compare results to simulations and manual measurements. Furthermore, we supplement the radar output with other sensor modalities, such as acoustic and vibration sensors. This method provides innovative solutions for detecting, identifying, and tracking vehicles and dismounts over a wide area in noisy conditions. This study presents a step towards distributed intelligent decision support and demonstrates effectiveness of small cheap sensors, which can complement advanced technologies in certain real-life scenarios. Full article

(This article belongs to the Special Issue Collaborative Sensors)

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31 pages, 1136 KiB

Open AccessArticle

On the Feasibility of Interoperable Schemes in Hand Biometrics

by Aythami Morales^*, Ester González and Miguel A. Ferrer

Instituto Universitario para el Desarrollo Tecnológico y la Innovación en Comunicaciones (IDeTIC), Universidad de Las Palmas de Gran Canaria, Campus de Tafira s/n, E-35017 Las Palmas de Gran Canaria, Spain

Sensors 2012, 12(2), 1352-1382; https://doi.org/10.3390/s120201352 - 1 Feb 2012

Cited by 11 | Viewed by 9083

Abstract

Personal recognition through hand-based biometrics has attracted the interest of many researchers in the last twenty years. A significant number of proposals based on different procedures and acquisition devices have been published in the literature. However, comparisons between devices and their interoperability have [...] Read more.

Personal recognition through hand-based biometrics has attracted the interest of many researchers in the last twenty years. A significant number of proposals based on different procedures and acquisition devices have been published in the literature. However, comparisons between devices and their interoperability have not been thoroughly studied. This paper tries to fill this gap by proposing procedures to improve the interoperability among different hand biometric schemes. The experiments were conducted on a database made up of 8,320 hand images acquired from six different hand biometric schemes, including a flat scanner, webcams at different wavelengths, high quality cameras, and contactless devices. Acquisitions on both sides of the hand were included. Our experiment includes four feature extraction methods which determine the best performance among the different scenarios for two of the most popular hand biometrics: hand shape and palm print. We propose smoothing techniques at the image and feature levels to reduce interdevice variability. Results suggest that comparative hand shape offers better performance in terms of interoperability than palm prints, but palm prints can be more effective when using similar sensors. Full article

(This article belongs to the Special Issue Hand-Based Biometrics Sensors and Systems)

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15 pages, 1072 KiB

Open AccessArticle

Multi-Sensor Arrays for Online Monitoring of Cell Dynamics in in vitro Studies with Choroid Plexus Epithelial Cells

by Pedro Mestres-Ventura^1,2,*, Andrea Morguet¹ and Soledad García Gómez de las Heras²

¹ Department of Anatomy and Cell Biology, Saarland University, University Hospital, Bldg. 61, 66421 Homburg, Saar, Germany

² Department of Human Histology and Pathology, Faculty for Health Sciences, University Rey Juan Carlos I, Av. de Atenas s/n, E-28922 Alcorcón, Madrid, Spain

Sensors 2012, 12(2), 1383-1397; https://doi.org/10.3390/s120201383 - 1 Feb 2012

Cited by 3 | Viewed by 9173

Abstract

Sensors and multi-sensor arrays are the basis of new technologies for the non-label monitoring of cell activity. In this paper we show that choroid plexus cells can be cultured on silicon chips and that sensors register in real time changes in their activity, [...] Read more.

Sensors and multi-sensor arrays are the basis of new technologies for the non-label monitoring of cell activity. In this paper we show that choroid plexus cells can be cultured on silicon chips and that sensors register in real time changes in their activity, constituting an interesting experimental paradigm for cell biology and medical research. To validate the signals recorded (metabolism = peri-cellular acidification, oxygen consumption = respiration; impedance = adhesion, cell shape and motility) we performed experiments with compounds that act in a well-known way on cells, influencing these parameters. Our in vitro model demonstrates the advantages of multi-sensor arrays in assessment and experimental characterization of dynamic cellular events—in this case in choroid plexus functions, however with applicability to other cell types as well. Full article

(This article belongs to the Special Issue Live Cell-Based Sensors)

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24 pages, 2030 KiB

Open AccessArticle

Use of a Real-Time Remote Monitoring Network (RTRM) to Characterize the Guadalquivir Estuary (Spain)

by Gabriel Navarro^1,*

, Isabel Emma Huertas¹, Eduardo Costas², Susana Flecha¹, Manuel Díez-Minguito³, Isabel Caballero¹

, Victoria López-Rodas², Laura Prieto¹ and Javier Ruiz¹

¹ Departamento de Ecología y Gestión Costera, Instituto de Ciencias Marinas de Andalucía, ICMAN-CSIC, Puerto Real, 11519, Cadiz, Spain

² Departamento de Producción Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, 28040, Spain

³ Grupo de Dinámica de Flujos Ambientales, Centro Andaluz de Medio Ambiente, Universidad de Granada, Avda. del Mediterráneo, Granada 18006, Spain

Sensors 2012, 12(2), 1398-1421; https://doi.org/10.3390/s120201398 - 1 Feb 2012

Cited by 50 | Viewed by 11370

Abstract

The temporal variability of hydrological variables in the Guadalquivir estuary was examined during three years through a real-time remote monitoring network (RTRM). The network was developed with the aim of studying the influence of hydrodynamical and hydrological features within the estuary on the [...] Read more.

The temporal variability of hydrological variables in the Guadalquivir estuary was examined during three years through a real-time remote monitoring network (RTRM). The network was developed with the aim of studying the influence of hydrodynamical and hydrological features within the estuary on the functioning of the pelagic ecosystem. Completing this data-gathering network, monthly cruises were performed in order to measure biogeochemical variables that are indicative of the trophic status of the aquatic environment. The results showed that several sources of physical forcing, such as wind, tide-associated currents and river discharge were responsible for the spatio-temporal patterns of dissolved oxygen, salinity and turbidity in the estuary. The analysis was conducted under tidal and flood regime, which allowed us to identify river discharge as the main forcing agent of the hydrology inside the estuary. In particular, episodes of elevated turbidity detected by the network, together with episodes of low salinity and dissolved oxygen were closely related to the increase in water supply from a dam located upstream. The network installed provided accurate data that can be rapidly used for research or educational applications and by policy-makers or agencies in charge of the management of the coastal area. Full article

(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks)

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15 pages, 621 KiB

Open AccessArticle

An Electronic Nose Based on Coated Piezoelectric Quartz Crystals to Certify Ewes’ Cheese and to Discriminate between Cheese Varieties

by Vânia F. Pais, João A. B. P. Oliveira

and Maria Teresa S. R. Gomes^*

CESAM & Department of Chemistry, University of Aveiro, Aveiro 3810-193, Portugal

Sensors 2012, 12(2), 1422-1436; https://doi.org/10.3390/s120201422 - 1 Feb 2012

Cited by 22 | Viewed by 9252

Abstract

An electronic nose based on coated piezoelectric quartz crystals was used to distinguish cheese made from ewes’ milk, and to distinguish cheese varieties. Two sensors coated with Nafion and Carbowax could certify half the ewes’ cheese samples, exclude 32 cheeses made from cow’s [...] Read more.

An electronic nose based on coated piezoelectric quartz crystals was used to distinguish cheese made from ewes’ milk, and to distinguish cheese varieties. Two sensors coated with Nafion and Carbowax could certify half the ewes’ cheese samples, exclude 32 cheeses made from cow’s milk and to classify half of the ewes’ cheese samples as possibly authentic. Two other sensors, coated with polyvinylpyrrolidone and triethanolamine clearly distinguished between Flamengo, Brie, Gruyère and Mozzarella cheeses. Brie cheeses were further separated according to their origin, and Mozzarella grated cheese also appeared clearly separated from non-grated Mozzarella. Full article

(This article belongs to the Section Chemical Sensors)

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18 pages, 1241 KiB

Open AccessArticle

Accuracy and Resolution of Kinect Depth Data for Indoor Mapping Applications

by Kourosh Khoshelham^* and Sander Oude Elberink

Faculty of Geo-Information Science and Earth Observation, University of Twente, P.O. Box 217, Enschede 7514 AE, The Netherlands

Sensors 2012, 12(2), 1437-1454; https://doi.org/10.3390/s120201437 - 1 Feb 2012

Cited by 1422 | Viewed by 69624

Abstract

Consumer-grade range cameras such as the Kinect sensor have the potential to be used in mapping applications where accuracy requirements are less strict. To realize this potential insight into the geometric quality of the data acquired by the sensor is essential. In this [...] Read more.

Consumer-grade range cameras such as the Kinect sensor have the potential to be used in mapping applications where accuracy requirements are less strict. To realize this potential insight into the geometric quality of the data acquired by the sensor is essential. In this paper we discuss the calibration of the Kinect sensor, and provide an analysis of the accuracy and resolution of its depth data. Based on a mathematical model of depth measurement from disparity a theoretical error analysis is presented, which provides an insight into the factors influencing the accuracy of the data. Experimental results show that the random error of depth measurement increases with increasing distance to the sensor, and ranges from a few millimeters up to about 4 cm at the maximum range of the sensor. The quality of the data is also found to be influenced by the low resolution of the depth measurements. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 2126 KiB

Open AccessArticle

An Aluminum Microfluidic Chip Fabrication Using a Convenient Micromilling Process for Fluorescent Poly(DL-lactide-co-glycolide) Microparticle Generation

by Yung-Sheng Lin^1,2, Chih-Hui Yang¹, Chih-Yu Wang³, Fang-Rong Chang⁴

, Keng-Shiang Huang^5,* and Wan-Chen Hsieh¹

¹ Department of Biological Science & Technology, I-Shou University, Kaohsiung 84001, Taiwan

² Department of Applied Cosmetology and Master Program of Cosmetic Science, Hung-Kuang University, Taichung 43302, Taiwan

³ Department of Biomedical Engineering, I-Shou University, Kaohsiung 82445, Taiwan

⁴ Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan

⁵ The School of Chinese Medicine for Post-Baccalaureate, I-Shou University, Kaohsiung 82445, Taiwan

Sensors 2012, 12(2), 1455-1467; https://doi.org/10.3390/s120201455 - 1 Feb 2012

Cited by 41 | Viewed by 11657

Abstract

This study presents the development of a robust aluminum-based microfluidic chip fabricated by conventional mechanical micromachining (computer numerical control-based micro-milling process). It applied the aluminum-based microfluidic chip to form poly(lactic-co-glycolic acid) (PLGA) microparticles encapsulating CdSe/ZnS quantum dots (QDs). A cross-flow design [...] Read more.

This study presents the development of a robust aluminum-based microfluidic chip fabricated by conventional mechanical micromachining (computer numerical control-based micro-milling process). It applied the aluminum-based microfluidic chip to form poly(lactic-co-glycolic acid) (PLGA) microparticles encapsulating CdSe/ZnS quantum dots (QDs). A cross-flow design and flow-focusing system were employed to control the oil-in-water (o/w) emulsification to ensure the generation of uniformly-sized droplets. The size of the droplets could be tuned by adjusting the flow rates of the water and oil phases. The proposed microfluidic platform is easy to fabricate, set up, organize as well as program, and is valuable for further applications under harsh reaction conditions (high temperature and/or strong organic solvent systems). The proposed method has the advantages of actively controlling the droplet diameter, with a narrow size distribution, good sphericity, as well as being a simple process with a high throughput. In addition to the fluorescent PLGA microparticles in this study, this approach can also be applied to many applications in the pharmaceutical and biomedical area. Full article

(This article belongs to the Special Issue Biochips)

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14 pages, 222 KiB

Open AccessArticle

Performance Study of the Application of Artificial Neural Networks to the Completion and Prediction of Data Retrieved by Underwater Sensors

by Carlos Baladrón^1,*, Javier M. Aguiar¹, Lorena Calavia¹, Belén Carro¹, Antonio Sánchez-Esguevillas¹ and Luis Hernández²

¹ Universidad de Valladolid, Dpto. TSyCeIT, ETSIT, Paseo de Belén 15, 47011 Valladolid, Spain

² CIEMAT, Autovía de Navarra A15, salida 56, Lubia, 42290 Soria, Spain

Sensors 2012, 12(2), 1468-1481; https://doi.org/10.3390/s120201468 - 2 Feb 2012

Cited by 21 | Viewed by 8634

Abstract

This paper presents a proposal for an Artificial Neural Network (ANN)-based architecture for completion and prediction of data retrieved by underwater sensors. Due to the specific conditions under which these sensors operate, it is not uncommon for them to fail, and maintenance operations [...] Read more.

This paper presents a proposal for an Artificial Neural Network (ANN)-based architecture for completion and prediction of data retrieved by underwater sensors. Due to the specific conditions under which these sensors operate, it is not uncommon for them to fail, and maintenance operations are difficult and costly. Therefore, completion and prediction of the missing data can greatly improve the quality of the underwater datasets. A performance study using real data is presented to validate the approach, concluding that the proposed architecture is able to provide very low errors. The numbers show as well that the solution is especially suitable for cases where large portions of data are missing, while in situations where the missing values are isolated the improvement over other simple interpolation methods is limited. Full article

(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks)

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12 pages, 438 KiB

Open AccessArticle

Embedded Palmprint Recognition System Using OMAP 3530

by Linlin Shen^*

, Shipei Wu, Songhao Zheng and Zhen Ji

Shenzhen Key Laboratory of Embedded System Design, School of Computer Science and Software Engineering, Shenzhen University, Shenzhen 518060, China

Sensors 2012, 12(2), 1482-1493; https://doi.org/10.3390/s120201482 - 2 Feb 2012

Cited by 18 | Viewed by 9708

Abstract

We have proposed in this paper an embedded palmprint recognition system using the dual-core OMAP 3530 platform. An improved algorithm based on palm code was proposed first. In this method, a Gabor wavelet is first convolved with the palmprint image to produce a [...] Read more.

We have proposed in this paper an embedded palmprint recognition system using the dual-core OMAP 3530 platform. An improved algorithm based on palm code was proposed first. In this method, a Gabor wavelet is first convolved with the palmprint image to produce a response image, where local binary patterns are then applied to code the relation among the magnitude of wavelet response at the ccentral pixel with that of its neighbors. The method is fully tested using the public PolyU palmprint database. While palm code achieves only about 89% accuracy, over 96% accuracy is achieved by the proposed G-LBP approach. The proposed algorithm was then deployed to the DSP processor of OMAP 3530 and work together with the ARM processor for feature extraction. When complicated algorithms run on the DSP processor, the ARM processor can focus on image capture, user interface and peripheral control. Integrated with an image sensing module and central processing board, the designed device can achieve accurate and real time performance. Full article

(This article belongs to the Special Issue Hand-Based Biometrics Sensors and Systems)

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15 pages, 490 KiB

Open AccessArticle

Miniaturized Protein Microarray with Internal Calibration as Point-of-Care Device for Diagnosis of Neonatal Sepsis

by Patricia Buchegger, Ursula Sauer

, Hedvig Toth-Székély and Claudia Preininger^*

Health & Environment Department, AIT Austrian Institute of Technology, Bioresources, Konrad Lorenz Straße 24, 3430 Tulln, Austria

Sensors 2012, 12(2), 1494-1508; https://doi.org/10.3390/s120201494 - 3 Feb 2012

Cited by 40 | Viewed by 9711

Abstract

Neonatal sepsis is still a leading cause of death among newborns. Therefore a protein-microarray for point-of-care testing that simultaneously quantifies the sepsis associated serum proteins IL-6, IL-8, IL-10, TNF alpha, S-100, PCT, E-Selectin, CRP and Neopterin has been developed. The chip works with [...] Read more.

Neonatal sepsis is still a leading cause of death among newborns. Therefore a protein-microarray for point-of-care testing that simultaneously quantifies the sepsis associated serum proteins IL-6, IL-8, IL-10, TNF alpha, S-100, PCT, E-Selectin, CRP and Neopterin has been developed. The chip works with only a 4 µL patient serum sample and hence minimizes excessive blood withdrawal from newborns. The 4 µL patient samples are diluted with 36 µL assay buffer and distributed to four slides for repetitive measurements. Streptavidin coated magnetic particles that act as distinct stirring detection components are added, not only to stir the sample, but also to detect antibody antigen binding events. We demonstrate that the test is complete within 2.5 h using a single step assay. S-100 conjugated to BSA is spotted in increasing concentrations to create an internal calibration. The presented low volume protein-chip fulfills the requirements of point-of-care testing for accurate and repeatable (CV < 14%) quantification of serum proteins for the diagnosis of neonatal sepsis. Full article

(This article belongs to the Special Issue Biochips)

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20 pages, 660 KiB

Open AccessArticle

Video Sensor Architecture for Surveillance Applications

by Jordi Sánchez, Ginés Benet^* and José E. Simó

Instituto de Automática e Informática Industrial (ai2), Universidad Politecnica de Valencia, C/. de Vera, s/n, E-46022 Valencia, Spain

Sensors 2012, 12(2), 1509-1528; https://doi.org/10.3390/s120201509 - 3 Feb 2012

Cited by 16 | Viewed by 8692

Abstract

This paper introduces a flexible hardware and software architecture for a smart video sensor. This sensor has been applied in a video surveillance application where some of these video sensors are deployed, constituting the sensory nodes of a distributed surveillance system. In this [...] Read more.

This paper introduces a flexible hardware and software architecture for a smart video sensor. This sensor has been applied in a video surveillance application where some of these video sensors are deployed, constituting the sensory nodes of a distributed surveillance system. In this system, a video sensor node processes images locally in order to extract objects of interest, and classify them. The sensor node reports the processing results to other nodes in the cloud (a user or higher level software) in the form of an XML description. The hardware architecture of each sensor node has been developed using two DSP processors and an FPGA that controls, in a flexible way, the interconnection among processors and the image data flow. The developed node software is based on pluggable components and runs on a provided execution run-time. Some basic and application-specific software components have been developed, in particular: acquisition, segmentation, labeling, tracking, classification and feature extraction. Preliminary results demonstrate that the system can achieve up to 7.5 frames per second in the worst case, and the true positive rates in the classification of objects are better than 80%. Full article

(This article belongs to the Section Physical Sensors)

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15 pages, 217 KiB

Open AccessArticle

An LDPC Decoder Architecture for Wireless Sensor Network Applications

by Andrea Dario Giancarlo Biroli, Maurizio Martina^* and Guido Masera

Dipartimento di Elettronica e Telecomunicazioni, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino 10129, Italy

Sensors 2012, 12(2), 1529-1543; https://doi.org/10.3390/s120201529 - 6 Feb 2012

Cited by 18 | Viewed by 8619

Abstract

The pervasive use of wireless sensors in a growing spectrum of human activities reinforces the need for devices with low energy dissipation. In this work, coded communication between a couple of wireless sensor devices is considered as a method to reduce the dissipated [...] Read more.

The pervasive use of wireless sensors in a growing spectrum of human activities reinforces the need for devices with low energy dissipation. In this work, coded communication between a couple of wireless sensor devices is considered as a method to reduce the dissipated energy per transmitted bit with respect to uncoded communication. Different Low Density Parity Check (LDPC) codes are considered to this purpose and post layout results are shown for a low-area low-energy decoder, which offers percentage energy savings with respect to the uncoded solution in the range of 40%–80%, depending on considered environment, distance and bit error rate. Full article

(This article belongs to the Special Issue Microprocessors and System-on-Chip)

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28 pages, 676 KiB

Open AccessReview

Pseudomonas fluorescens HK44: Lessons Learned from a Model Whole-Cell Bioreporter with a Broad Application History

by Josef Trögl^1,*

, Archana Chauhan², Steven Ripp², Alice C. Layton², Gabriela Kuncová³ and Gary S. Sayler²

¹ Faculty of the Environment, Jan Evangelista Purkyně University in Ústí nad Labem, Králova Výšina 3132/7, 400 96 Ústí nad Labem, Czech Republic

² The Center for Environmental Biotechnology, The University of Tennessee, 676 Dabney Hall, Knoxville, TN 37996, USA

³ Institute of Chemical Process Fundamentals of ASCR, v.v.i., Rozvojová 135, 165 02, Prague 6-Suchdol, Czech Republic

Sensors 2012, 12(2), 1544-1571; https://doi.org/10.3390/s120201544 - 6 Feb 2012

Cited by 32 | Viewed by 12503

Abstract

Initially described in 1990, Pseudomonas fluorescens HK44 served as the first whole-cell bioreporter genetically endowed with a bioluminescent (luxCDABE) phenotype directly linked to a catabolic (naphthalene degradative) pathway. HK44 was the first genetically engineered microorganism to be released in the field [...] Read more.

Initially described in 1990, Pseudomonas fluorescens HK44 served as the first whole-cell bioreporter genetically endowed with a bioluminescent (luxCDABE) phenotype directly linked to a catabolic (naphthalene degradative) pathway. HK44 was the first genetically engineered microorganism to be released in the field to monitor bioremediation potential. Subsequent to that release, strain HK44 had been introduced into other solids (soils, sands), liquid (water, wastewater), and volatile environments. In these matrices, it has functioned as one of the best characterized chemically-responsive environmental bioreporters and as a model organism for understanding bacterial colonization and transport, cell immobilization strategies, and the kinetics of cellular bioluminescent emission. This review summarizes the characteristics of P. fluorescens HK44 and the extensive range of its applications with special focus on the monitoring of bioremediation processes and biosensing of environmental pollution. Full article

(This article belongs to the Special Issue Live Cell-Based Sensors)

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22 pages, 3212 KiB

Open AccessArticle

Method for Reading Sensors and Controlling Actuators Using Audio Interfaces of Mobile Devices

by Rafael V. Aroca^*, Aquiles F. Burlamaqui and Luiz M. G. Gonçalves

NatalNet Laboratory, Technology Center, Computing Engineering and Automation Department, Federal University of Rio Grande do Norte, Natal, RN 59078-900, Brazil

Sensors 2012, 12(2), 1572-1593; https://doi.org/10.3390/s120201572 - 6 Feb 2012

Cited by 8 | Viewed by 13404

Abstract

This article presents a novel closed loop control architecture based on audio channels of several types of computing devices, such as mobile phones and tablet computers, but not restricted to them. The communication is based on an audio interface that relies on the [...] Read more.

This article presents a novel closed loop control architecture based on audio channels of several types of computing devices, such as mobile phones and tablet computers, but not restricted to them. The communication is based on an audio interface that relies on the exchange of audio tones, allowing sensors to be read and actuators to be controlled. As an application example, the presented technique is used to build a low cost mobile robot, but the system can also be used in a variety of mechatronics applications and sensor networks, where smartphones are the basic building blocks. Full article

(This article belongs to the Special Issue Ubiquitous Sensing)

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18 pages, 1651 KiB

Open AccessArticle

Gait Analysis Using Floor Markers and Inertial Sensors

by Tri Nhut Do and Young Soo Suh^*

School of Electrical Engineering, University of Ulsan, Mugeo 2-Dong, Nam gu, Ulsan City 680-749, Korea

Sensors 2012, 12(2), 1594-1611; https://doi.org/10.3390/s120201594 - 7 Feb 2012

Cited by 38 | Viewed by 9228

Abstract

In this paper, a gait analysis system which estimates step length and foot angles is proposed. A measurement unit, which consists of a camera and inertial sensors, is installed on a shoe. When the foot touches the floor, markers are recognized by the [...] Read more.

In this paper, a gait analysis system which estimates step length and foot angles is proposed. A measurement unit, which consists of a camera and inertial sensors, is installed on a shoe. When the foot touches the floor, markers are recognized by the camera to obtain the current position and attitude. A simple planar marker with 4,096 different codes is used. These markers printed on paper are placed on the floor. When the foot is moving off the floor, the position and attitude are estimated using an inertial navigation algorithm. For accurate estimation, a smoother is proposed, where vision information and inertial sensor data are combined. Through experiments, it is shown that the proposed system can both track foot motion and estimate step length. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 806 KiB

Open AccessArticle

Fast Decision Algorithms in Low-Power Embedded Processors for Quality-of-Service Based Connectivity of Mobile Sensors in Heterogeneous Wireless Sensor Networks

by María D. Jaraíz-Simón, Juan A. Gómez-Pulido^*

, Miguel A. Vega-Rodríguez and Juan M. Sánchez-Pérez

Department of Technologies of Computers and Communications, Polytechnic School, University of Extremadura, Campus Universitario s/n, 10003 Cáceres, Spain

Sensors 2012, 12(2), 1612-1624; https://doi.org/10.3390/s120201612 - 7 Feb 2012

Cited by 6 | Viewed by 7678

Abstract

When a mobile wireless sensor is moving along heterogeneous wireless sensor networks, it can be under the coverage of more than one network many times. In these situations, the Vertical Handoff process can happen, where the mobile sensor decides to change its connection [...] Read more.

When a mobile wireless sensor is moving along heterogeneous wireless sensor networks, it can be under the coverage of more than one network many times. In these situations, the Vertical Handoff process can happen, where the mobile sensor decides to change its connection from a network to the best network among the available ones according to their quality of service characteristics. A fitness function is used for the handoff decision, being desirable to minimize it. This is an optimization problem which consists of the adjustment of a set of weights for the quality of service. Solving this problem efficiently is relevant to heterogeneous wireless sensor networks in many advanced applications. Numerous works can be found in the literature dealing with the vertical handoff decision, although they all suffer from the same shortfall: a non-comparable efficiency. Therefore, the aim of this work is twofold: first, to develop a fast decision algorithm that explores the entire space of possible combinations of weights, searching that one that minimizes the fitness function; and second, to design and implement a system on chip architecture based on reconfigurable hardware and embedded processors to achieve several goals necessary for competitive mobile terminals: good performance, low power consumption, low economic cost, and small area integration. Full article

(This article belongs to the Special Issue Microprocessors and System-on-Chip)

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23 pages, 540 KiB

Open AccessArticle

E-SAP: Efficient-Strong Authentication Protocol for Healthcare Applications Using Wireless Medical Sensor Networks

by Pardeep Kumar¹, Sang-Gon Lee² and Hoon-Jae Lee^2,*

¹ Department of Ubiquitous-IT, Graduate School of Design & IT, Dongseo University, Sasang-Gu, Busan 617-716, Korea

² Division of Computer & Information Engineering, Dongseo University, San 69-1, Jurye-2-Dong, Sasang-Gu, Busan 617-716, Korea

Sensors 2012, 12(2), 1625-1647; https://doi.org/10.3390/s120201625 - 7 Feb 2012

Cited by 199 | Viewed by 14827

Abstract

A wireless medical sensor network (WMSN) can sense humans’ physiological signs without sacrificing patient comfort and transmit patient vital signs to health professionals’ hand-held devices. The patient physiological data are highly sensitive and WMSNs are extremely vulnerable to many attacks. Therefore, it must [...] Read more.

A wireless medical sensor network (WMSN) can sense humans’ physiological signs without sacrificing patient comfort and transmit patient vital signs to health professionals’ hand-held devices. The patient physiological data are highly sensitive and WMSNs are extremely vulnerable to many attacks. Therefore, it must be ensured that patients’ medical signs are not exposed to unauthorized users. Consequently, strong user authentication is the main concern for the success and large scale deployment of WMSNs. In this regard, this paper presents an efficient, strong authentication protocol, named E-SAP, for healthcare application using WMSNs. The proposed E-SAP includes: (1) a two-factor (i.e., password and smartcard) professional authentication; (2) mutual authentication between the professional and the medical sensor; (3) symmetric encryption/decryption for providing message confidentiality; (4) establishment of a secure session key at the end of authentication; and (5) professionals can change their password. Further, the proposed protocol requires three message exchanges between the professional, medical sensor node and gateway node, and achieves efficiency (i.e., low computation and communication cost). Through the formal analysis, security analysis and performance analysis, we demonstrate that E-SAP is more secure against many practical attacks, and allows a tradeoff between the security and the performance cost for healthcare application using WMSNs. Full article

(This article belongs to the Section Sensor Networks)

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9 pages, 168 KiB

Open AccessReview

Protein Reporter Bioassay Systems for the Phenotypic Screening of Candidate Drugs: A Mouse Platform for Anti-Aging Drug Screening

by Takuya Chiba^1,*, Tomoshi Tsuchiya², Ryoichi Mori¹ and Isao Shimokawa¹

¹ Department of Investigative Pathology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan

² Division of Surgical Oncology, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan

Sensors 2012, 12(2), 1648-1656; https://doi.org/10.3390/s120201648 - 7 Feb 2012

Cited by 13 | Viewed by 8497

Abstract

Recent drug discovery efforts have utilized high throughput screening (HTS) of large chemical libraries to identify compounds that modify the activity of discrete molecular targets. The molecular target approach to drug screening is widely used in the pharmaceutical and biotechnology industries, because of [...] Read more.

Recent drug discovery efforts have utilized high throughput screening (HTS) of large chemical libraries to identify compounds that modify the activity of discrete molecular targets. The molecular target approach to drug screening is widely used in the pharmaceutical and biotechnology industries, because of the amount of knowledge now available regarding protein structure that has been obtained by computer simulation. The molecular target approach requires that the structure of target molecules, and an understanding of their physiological functions, is known. This approach to drug discovery may, however, limit the identification of novel drugs. As an alternative, the phenotypic- or pathway-screening approach to drug discovery is gaining popularity, particularly in the academic sector. This approach not only provides the opportunity to identify promising drug candidates, but also enables novel information regarding biological pathways to be unveiled. Reporter assays are a powerful tool for the phenotypic screening of compound libraries. Of the various reporter genes that can be used in such assays, those encoding secreted proteins enable the screening of hit molecules in both living cells and animals. Cell- and animal-based screens enable simultaneous evaluation of drug metabolism or toxicity with biological activity. Therefore, drug candidates identified in these screens may have increased biological efficacy and a lower risk of side effects in humans. In this article, we review the reporter bioassay systems available for phenotypic drug discovery. Full article

(This article belongs to the Special Issue Bioassays)

31 pages, 619 KiB

Open AccessReview

Noble Metal Nanoparticles for Biosensing Applications

by Gonçalo Doria¹, João Conde^1,2, Bruno Veigas^1,3, Leticia Giestas¹, Carina Almeida¹, Maria Assunção¹, João Rosa^1,4 and Pedro V. Baptista^1,*

¹ CIGMH, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal

² Instituto de Nanociencia de Aragón, Universidad de Zaragoza, Campus Río Ebro, Edifício I+D, Mariano Esquillor, s/n, 50018 Zaragoza, Spain

³ CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal

⁴ REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal

Sensors 2012, 12(2), 1657-1687; https://doi.org/10.3390/s120201657 - 7 Feb 2012

Cited by 637 | Viewed by 29675

Abstract

In the last decade the use of nanomaterials has been having a great impact in biosensing. In particular, the unique properties of noble metal nanoparticles have allowed for the development of new biosensing platforms with enhanced capabilities in the specific detection of bioanalytes. [...] Read more.

In the last decade the use of nanomaterials has been having a great impact in biosensing. In particular, the unique properties of noble metal nanoparticles have allowed for the development of new biosensing platforms with enhanced capabilities in the specific detection of bioanalytes. Noble metal nanoparticles show unique physicochemical properties (such as ease of functionalization via simple chemistry and high surface-to-volume ratios) that allied with their unique spectral and optical properties have prompted the development of a plethora of biosensing platforms. Additionally, they also provide an additional or enhanced layer of application for commonly used techniques, such as fluorescence, infrared and Raman spectroscopy. Herein we review the use of noble metal nanoparticles for biosensing strategies—from synthesis and functionalization to integration in molecular diagnostics platforms, with special focus on those that have made their way into the diagnostics laboratory. Full article

(This article belongs to the Special Issue Nano-Biosensors)

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14 pages, 511 KiB

Open AccessArticle

A Web Service-Based Framework Model for People-Centric Sensing Applications Applied to Social Networking

by David Nunes^*, Thanh-Dien Tran, Duarte Raposo

, André Pinto, André Gomes and Jorge Sá Silva

Department of Informatics Engineering, University of Coimbra, Pólo II, Pinhal de Marrocos, Coimbra 3030-290, Portugal

Sensors 2012, 12(2), 1688-1701; https://doi.org/10.3390/s120201688 - 7 Feb 2012

Cited by 6 | Viewed by 9157

Abstract

As the Internet evolved, social networks (such as Facebook) have bloomed and brought together an astonishing number of users. Mashing up mobile phones and sensors with these social environments enables the creation of people-centric sensing systems which have great potential for expanding our [...] Read more.

As the Internet evolved, social networks (such as Facebook) have bloomed and brought together an astonishing number of users. Mashing up mobile phones and sensors with these social environments enables the creation of people-centric sensing systems which have great potential for expanding our current social networking usage. However, such systems also have many associated technical challenges, such as privacy concerns, activity detection mechanisms or intermittent connectivity, as well as limitations due to the heterogeneity of sensor nodes and networks. Considering the openness of the Web 2.0, good technical solutions for these cases consist of frameworks that expose sensing data and functionalities as common Web-Services. This paper presents our RESTful Web Service-based model for people-centric sensing frameworks, which uses sensors and mobile phones to detect users’ activities and locations, sharing this information amongst the user’s friends within a social networking site. We also present some screenshot results of our experimental prototype. Full article

(This article belongs to the Special Issue Microprocessors and System-on-Chip)

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18 pages, 1526 KiB

Open AccessArticle

Social Network Extraction and Analysis Based on Multimodal Dyadic Interaction

by Sergio Escalera^1,2,*, Xavier Baró^1,3, Jordi Vitrià^1,2, Petia Radeva^1,2 and Bogdan Raducanu¹

¹ Centre de Visió per Computador, Campus UAB, Edifici O, Bellaterra, 08193 Barcelona, Spain

² Department Matemàtica Aplicada i Anàlisi, Universitat de Barcelona, Gran Via 585, 08007 Barcelona, Spain

³ Estudis d’Informàtica, Multimèdia i Telecomunicació, Universitat Oberta de Catalunya, Rambla del Poblenou 156, 08018 Barcelona, Spain

Sensors 2012, 12(2), 1702-1719; https://doi.org/10.3390/s120201702 - 7 Feb 2012

Cited by 11 | Viewed by 9076

Abstract

Social interactions are a very important component in people’s lives. Social network analysis has become a common technique used to model and quantify the properties of social interactions. In this paper, we propose an integrated framework to explore the characteristics of a social [...] Read more.

Social interactions are a very important component in people’s lives. Social network analysis has become a common technique used to model and quantify the properties of social interactions. In this paper, we propose an integrated framework to explore the characteristics of a social network extracted from multimodal dyadic interactions. For our study, we used a set of videos belonging to New York Times’ Blogging Heads opinion blog. The Social Network is represented as an oriented graph, whose directed links are determined by the Influence Model. The links’ weights are a measure of the “influence” a person has over the other. The states of the Influence Model encode automatically extracted audio/visual features from our videos using state-of-the art algorithms. Our results are reported in terms of accuracy of audio/visual data fusion for speaker segmentation and centrality measures used to characterize the extracted social network. Full article

(This article belongs to the Section Physical Sensors)

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18 pages, 675 KiB

Open AccessArticle

Signal Processing of MEMS Gyroscope Arrays to Improve Accuracy Using a 1st Order Markov for Rate Signal Modeling

by Chengyu Jiang^*, Liang Xue, Honglong Chang, Guangmin Yuan and Weizheng Yuan

Micro and Nano Electromechanical System Laboratory, Northwestern Polytechnical University, 127 Youyi West Road, Xi’an 710072, Shaanxi, China

Sensors 2012, 12(2), 1720-1737; https://doi.org/10.3390/s120201720 - 7 Feb 2012

Cited by 46 | Viewed by 13508

Abstract

This paper presents a signal processing technique to improve angular rate accuracy of the gyroscope by combining the outputs of an array of MEMS gyroscope. A mathematical model for the accuracy improvement was described and a Kalman filter (KF) was designed to obtain [...] Read more.

This paper presents a signal processing technique to improve angular rate accuracy of the gyroscope by combining the outputs of an array of MEMS gyroscope. A mathematical model for the accuracy improvement was described and a Kalman filter (KF) was designed to obtain optimal rate estimates. Especially, the rate signal was modeled by a first-order Markov process instead of a random walk to improve overall performance. The accuracy of the combined rate signal and affecting factors were analyzed using a steady-state covariance. A system comprising a six-gyroscope array was developed to test the presented KF. Experimental tests proved that the presented model was effective at improving the gyroscope accuracy. The experimental results indicated that six identical gyroscopes with an ARW noise of 6.2 °/√h and a bias drift of 54.14 °/h could be combined into a rate signal with an ARW noise of 1.8 °/√h and a bias drift of 16.3 °/h, while the estimated rate signal by the random walk model has an ARW noise of 2.4 °/√h and a bias drift of 20.6 °/h. It revealed that both models could improve the angular rate accuracy and have a similar performance in static condition. In dynamic condition, the test results showed that the first-order Markov process model could reduce the dynamic errors 20% more than the random walk model. Full article

(This article belongs to the Special Issue Modeling, Testing and Reliability Issues in MEMS Engineering 2011)

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20 pages, 1038 KiB

Open AccessArticle

Finger Vein Recognition Based on a Personalized Best Bit Map

by Gongping Yang, Xiaoming Xi and Yilong Yin^*

School of Computer Science and Technology, Shandong University, Jinan 250101, China

Sensors 2012, 12(2), 1738-1757; https://doi.org/10.3390/s120201738 - 9 Feb 2012

Cited by 113 | Viewed by 13840

Abstract

Finger vein patterns have recently been recognized as an effective biometric identifier. In this paper, we propose a finger vein recognition method based on a personalized best bit map (PBBM). Our method is rooted in a local binary pattern based method and then [...] Read more.

Finger vein patterns have recently been recognized as an effective biometric identifier. In this paper, we propose a finger vein recognition method based on a personalized best bit map (PBBM). Our method is rooted in a local binary pattern based method and then inclined to use the best bits only for matching. We first present the concept of PBBM and the generating algorithm. Then we propose the finger vein recognition framework, which consists of preprocessing, feature extraction, and matching. Finally, we design extensive experiments to evaluate the effectiveness of our proposal. Experimental results show that PBBM achieves not only better performance, but also high robustness and reliability. In addition, PBBM can be used as a general framework for binary pattern based recognition. Full article

(This article belongs to the Special Issue Hand-Based Biometrics Sensors and Systems)

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13 pages, 683 KiB

Open AccessArticle

Comparison between Conduction and Convection Effects on Self-Heating in Doped Microcantilevers

by Mohd Zahid Ansari and Chongdu Cho^*

Department of Mechanical Engineering, Inha University, 253 Yonghyun-dong, Nam-Ku, Incheon 402-751, Korea

Sensors 2012, 12(2), 1758-1770; https://doi.org/10.3390/s120201758 - 9 Feb 2012

Cited by 3 | Viewed by 5700

Abstract

The present study investigates the effects of thermal conduction and convection on self-heating temperatures and bimetallic deflections produced in doped microcantilever sensors. These cantilevers are commonly used as sensors and actuators in microsystems. The cantilever is a monolith, multi-layer structure with a thin [...] Read more.

The present study investigates the effects of thermal conduction and convection on self-heating temperatures and bimetallic deflections produced in doped microcantilever sensors. These cantilevers are commonly used as sensors and actuators in microsystems. The cantilever is a monolith, multi-layer structure with a thin U-shaped element inside. The cantilever substrate is made of silicon and silicon dioxide, respectively, and the element is p-doped silicon. A numerical analysis package (ANSYS) is used to study the effect of cantilever substrate material, element width, applied voltage and the operating environments on cantilever characteristics. The numerical results for temperature are compared against their analytical models. Results indicate the numerical results are accurate within 6% of analytical, and Si/Si cantilevers are more suitable for biosensors and AFM, whereas, Si/SiO₂ are for hotplates and actuators applications. Full article

(This article belongs to the Section Biosensors)

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29 pages, 2970 KiB

Open AccessArticle

Vector Disparity Sensor with Vergence Control for Active Vision Systems

by Francisco Barranco^1,*

, Javier Diaz¹, Agostino Gibaldi², Silvio P. Sabatini² and Eduardo Ros¹

¹ Department of Computer Architecture and Technology, CITIC, ETSIIT, University of Granada, C/Daniel Saucedo Aranda s/n, E18071, Granada, Spain

² PSPC Group, Department of Biophysical and Electronic Engineering (DIBE), University of Genoa, Via Opera Pia 11A, I-16145, Genoa, Italy

Sensors 2012, 12(2), 1771-1799; https://doi.org/10.3390/s120201771 - 9 Feb 2012

Cited by 6 | Viewed by 8515

Abstract

This paper presents an architecture for computing vector disparity for active vision systems as used on robotics applications. The control of the vergence angle of a binocular system allows us to efficiently explore dynamic environments, but requires a generalization of the disparity computation [...] Read more.

This paper presents an architecture for computing vector disparity for active vision systems as used on robotics applications. The control of the vergence angle of a binocular system allows us to efficiently explore dynamic environments, but requires a generalization of the disparity computation with respect to a static camera setup, where the disparity is strictly 1-D after the image rectification. The interaction between vision and motor control allows us to develop an active sensor that achieves high accuracy of the disparity computation around the fixation point, and fast reaction time for the vergence control. In this contribution, we address the development of a real-time architecture for vector disparity computation using an FPGA device. We implement the disparity unit and the control module for vergence, version, and tilt to determine the fixation point. In addition, two on-chip different alternatives for the vector disparity engines are discussed based on the luminance (gradient-based) and phase information of the binocular images. The multiscale versions of these engines are able to estimate the vector disparity up to 32 fps on VGA resolution images with very good accuracy as shown using benchmark sequences with known ground-truth. The performances in terms of frame-rate, resource utilization, and accuracy of the presented approaches are discussed. On the basis of these results, our study indicates that the gradient-based approach leads to the best trade-off choice for the integration with the active vision system. Full article

(This article belongs to the Section Physical Sensors)

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16 pages, 566 KiB

Open AccessArticle

A Platform for Combined DNA and Protein Microarrays Based on Total Internal Reflection Fluorescence

by Alexander Asanov^1,*, Angélica Zepeda^2,* and Luis Vaca³

¹ TIRF Technologies, 951 Aviation Parkway, Suite 700, Morrisville, NC 27560, USA

² Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, DF 04510, México

³ Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, DF 04510, México

Sensors 2012, 12(2), 1800-1815; https://doi.org/10.3390/s120201800 - 9 Feb 2012

Cited by 22 | Viewed by 10063

Abstract

We have developed a novel microarray technology based on total internal reflection fluorescence (TIRF) in combination with DNA and protein bioassays immobilized at the TIRF surface. Unlike conventional microarrays that exhibit reduced signal-to-background ratio, require several stages of incubation, rinsing and stringency control, [...] Read more.

We have developed a novel microarray technology based on total internal reflection fluorescence (TIRF) in combination with DNA and protein bioassays immobilized at the TIRF surface. Unlike conventional microarrays that exhibit reduced signal-to-background ratio, require several stages of incubation, rinsing and stringency control, and measure only end-point results, our TIRF microarray technology provides several orders of magnitude better signal-to-background ratio, performs analysis rapidly in one step, and measures the entire course of association and dissociation kinetics between target DNA and protein molecules and the bioassays. In many practical cases detection of only DNA or protein markers alone does not provide the necessary accuracy for diagnosing a disease or detecting a pathogen. Here we describe TIRF microarrays that detect DNA and protein markers simultaneously, which reduces the probabilities of false responses. Supersensitive and multiplexed TIRF DNA and protein microarray technology may provide a platform for accurate diagnosis or enhanced research studies. Our TIRF microarray system can be mounted on upright or inverted microscopes or interfaced directly with CCD cameras equipped with a single objective, facilitating the development of portable devices. As proof-of-concept we applied TIRF microarrays for detecting molecular markers from Bacillus anthracis, the pathogen responsible for anthrax. Full article

(This article belongs to the Special Issue Synthetic Fluorescent Indicators for Low Molecular Weight Organic Metabolites)

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11 pages, 924 KiB

Open AccessArticle

Evaluation of Electrical and Optical Plethysmography Sensors for Noninvasive Monitoring of Hemoglobin Concentration

by Justin P. Phillips^*, Michelle Hickey and Panayiotis A. Kyriacou

School of Engineering and Mathematical Sciences, City University London, Northampton Square, London EC1V 0HB, UK

Sensors 2012, 12(2), 1816-1826; https://doi.org/10.3390/s120201816 - 9 Feb 2012

Cited by 21 | Viewed by 11172

Abstract

Completely noninvasive monitoring of hemoglobin concentration has not yet been fully realized in the clinical setting. This study investigates the viability of measuring hemoglobin concentration noninvasively by evaluating the performance of two types of sensor using a tissue phantom perfused with a blood [...] Read more.

Completely noninvasive monitoring of hemoglobin concentration has not yet been fully realized in the clinical setting. This study investigates the viability of measuring hemoglobin concentration noninvasively by evaluating the performance of two types of sensor using a tissue phantom perfused with a blood substitute. An electrical sensor designed to measure blood volume changes during the cardiac cycle was used together with an infrared optical sensor for detection of erythrocyte-bound hemoglobin. Both sensors demonstrated sensitivity to changes in pulse volume (plethysmography). The electrical sensor produced a signal referred to as capacitance plethysmograph (CPG) a quantity which was invariant to the concentration of an infrared absorbing dye present in the blood substitute. The optical sensor signal (photoplethysmograph) increased in amplitude with increasing absorber concentration. The ratio PPG:CPG is invariant to pulse pressure. This quantity is discussed as a possible index of in vivo hemoglobin concentration. Full article

(This article belongs to the Special Issue Optical Sensors in Medicine)

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19 pages, 383 KiB

Open AccessArticle

AURP: An AUV-Aided Underwater Routing Protocol for Underwater Acoustic Sensor Networks

by Seokhoon Yoon^*, Abul K. Azad, Hoon Oh and Sunghwan Kim^*

School of Electrical Engineering, University of Ulsan, Ulsan 680-749, Korea

Sensors 2012, 12(2), 1827-1845; https://doi.org/10.3390/s120201827 - 9 Feb 2012

Cited by 137 | Viewed by 13133

Abstract

Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address [...] Read more.

Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol), which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs). In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy consumption can be achieved. Full article

(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks)

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17 pages, 1234 KiB

Open AccessArticle

Extraction and Analysis of Impervious Surfaces Based on a Spectral Un-Mixing Method Using Pearl River Delta of China Landsat TM/ETM+ Imagery from 1998 to 2008

by Yingbin Deng, Fenglei Fan^*

and Renrong Chen

School of Geography, South China Normal University, Guangzhou, Guangdong 510631, China

Sensors 2012, 12(2), 1846-1862; https://doi.org/10.3390/s120201846 - 9 Feb 2012

Cited by 46 | Viewed by 9103

Abstract

Impervious surface area (ISA) is considered as an indicator of environment change and is regarded as an important input parameter for hydrological cycle simulation, water management and area pollution assessment. The Pearl River Delta (PRD), the 3rd most important economic district of China, [...] Read more.

Impervious surface area (ISA) is considered as an indicator of environment change and is regarded as an important input parameter for hydrological cycle simulation, water management and area pollution assessment. The Pearl River Delta (PRD), the 3rd most important economic district of China, is chosen in this paper to extract the ISA information based on Landsat images of 1998, 2003 and 2008 by using a linear spectral un-mixing method and to monitor impervious surface change by analyzing the multi-temporal Landsat-derived fractional impervious surface. Results of this study were as follows: (1) the area of ISA in the PRD increased 79.09% from 1998 to 2003 and 26.88% from 2003 to 2008 separately; (2) the spatial distribution of ISA was described according to the 1998/2003 percentage respectively. Most of middle and high percentage ISA was located in northwestern and southeastern of the whole delta, and middle percentage ISA was mainly located in the city interior, high percentage ISA was mainly located in the suburban around the city accordingly; (3) the expanding direction and trend of high percentage ISA was discussed in order to understand the change of urban in this delta; High percentage ISA moved from inner city to edge of urban area during 1998–2003 and moved to the suburban area that far from the urban area mixed with jumpily and gradually during 2003–2008. According to the discussion of high percentage ISA spatial expanded direction, it could be found out that high percentage ISA moved outward from the centre line of Pearl River of the whole delta while a high ISA percentage in both shores of the Pearl River Estuary moved toward the Pearl River; (4) combining the change of ISA with social conditions, the driving relationship was analyzed in detail. It was evident that ISA percentage change had a deep relationship with the economic development of this region in the past ten years. Contemporaneous major sport events (16th Asia Games of Guangzhou, 26th Summer Universidad of Shenzhen) and the government policies also promoted the development of the ISA. Meanwhile, topographical features like the National Nature Reserve of China restricted and affected the expansion of the ISA. Above all, this paper attempted to extract ISA in a major region of the PRD; the temporal and spatial analyses to PRD ISA demonstrated the drastic changes in developed areas of China. These results were important and valuable for land use management, ecological protection and policy establishment. Full article

(This article belongs to the Section Remote Sensors)

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22 pages, 1008 KiB

Open AccessArticle

Parametric Dense Stereovision Implementation on a System-on Chip (SoC)

by Alfredo Gardel^1,*

, Pablo Montejo², Jorge García¹, Ignacio Bravo¹

and José L. Lázaro¹

¹ Electronics Department, University of Alcala, Alcalá de Henares, Madrid 28871, Spain

² Higher Polytechnic Institute José Antonio Echeverría (CUJAE), La Habana, 19390, Cuba

Sensors 2012, 12(2), 1863-1884; https://doi.org/10.3390/s120201863 - 10 Feb 2012

Cited by 8 | Viewed by 8400

Abstract

This paper proposes a novel hardware implementation of a dense recovery of stereovision 3D measurements. Traditionally 3D stereo systems have imposed the maximum number of stereo correspondences, introducing a large restriction on artificial vision algorithms. The proposed system-on-chip (SoC) provides great performance and [...] Read more.

This paper proposes a novel hardware implementation of a dense recovery of stereovision 3D measurements. Traditionally 3D stereo systems have imposed the maximum number of stereo correspondences, introducing a large restriction on artificial vision algorithms. The proposed system-on-chip (SoC) provides great performance and efficiency, with a scalable architecture available for many different situations, addressing real time processing of stereo image flow. Using double buffering techniques properly combined with pipelined processing, the use of reconfigurable hardware achieves a parametrisable SoC which gives the designer the opportunity to decide its right dimension and features. The proposed architecture does not need any external memory because the processing is done as image flow arrives. Our SoC provides 3D data directly without the storage of whole stereo images. Our goal is to obtain high processing speed while maintaining the accuracy of 3D data using minimum resources. Configurable parameters may be controlled by later/parallel stages of the vision algorithm executed on an embedded processor. Considering hardware FPGA clock of 100 MHz, image flows up to 50 frames per second (fps) of dense stereo maps of more than 30,000 depth points could be obtained considering 2 Mpix images, with a minimum initial latency. The implementation of computer vision algorithms on reconfigurable hardware, explicitly low level processing, opens up the prospect of its use in autonomous systems, and they can act as a coprocessor to reconstruct 3D images with high density information in real time. Full article

(This article belongs to the Special Issue Microprocessors and System-on-Chip)

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13 pages, 755 KiB

Open AccessArticle

Gen-2 Hand-Held Optical Imager towards Cancer Imaging: Reflectance and Transillumination Phantom Studies

by Jean Gonzalez, Manuela Roman, Michael Hall and Anuradha Godavarty^*

Optical Imaging Laboratory, Department of Biomedical Engineering, Florida International University, 10555 W. Flagler St., Miami, FL 33174, USA

Sensors 2012, 12(2), 1885-1897; https://doi.org/10.3390/s120201885 - 10 Feb 2012

Cited by 15 | Viewed by 8063

Abstract

Hand-held near-infrared (NIR) optical imagers are developed by various researchers towards non-invasive clinical breast imaging. Unlike these existing imagers that can perform only reflectance imaging, a generation-2 (Gen-2) hand-held optical imager has been recently developed to perform both reflectance and transillumination imaging. The [...] Read more.

Hand-held near-infrared (NIR) optical imagers are developed by various researchers towards non-invasive clinical breast imaging. Unlike these existing imagers that can perform only reflectance imaging, a generation-2 (Gen-2) hand-held optical imager has been recently developed to perform both reflectance and transillumination imaging. The unique forked design of the hand-held probe head(s) allows for reflectance imaging (as in ultrasound) and transillumination or compressed imaging (as in X-ray mammography). Phantom studies were performed to demonstrate two-dimensional (2D) target detection via reflectance and transillumination imaging at various target depths (1–5 cm deep) and using simultaneous multiple point illumination approach. It was observed that 0.45 cc targets were detected up to 5 cm deep during transillumination, but limited to 2.5 cm deep during reflectance imaging. Additionally, implementing appropriate data post-processing techniques along with a polynomial fitting approach, to plot 2D surface contours of the detected signal, yields distinct target detectability and localization. The ability of the gen-2 imager to perform both reflectance and transillumination imaging allows its direct comparison to ultrasound and X-ray mammography results, respectively, in future clinical breast imaging studies. Full article

(This article belongs to the Special Issue Optical Sensors in Medicine)

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21 pages, 867 KiB

Open AccessReview

Fiber Bragg Grating Sensors for Harsh Environments

by Stephen J. Mihailov

Communications Research Centre Canada, 3701 Carling Avenue, P.O. Box 11490, Station H, Ottawa, ON K2H 8S2, Canada

Sensors 2012, 12(2), 1898-1918; https://doi.org/10.3390/s120201898 - 10 Feb 2012

Cited by 796 | Viewed by 32610

Abstract

Because of their small size, passive nature, immunity to electromagnetic interference, and capability to directly measure physical parameters such as temperature and strain, fiber Bragg grating sensors have developed beyond a laboratory curiosity and are becoming a mainstream sensing technology. Recently, high temperature [...] Read more.

Because of their small size, passive nature, immunity to electromagnetic interference, and capability to directly measure physical parameters such as temperature and strain, fiber Bragg grating sensors have developed beyond a laboratory curiosity and are becoming a mainstream sensing technology. Recently, high temperature stable gratings based on regeneration techniques and femtosecond infrared laser processing have shown promise for use in extreme environments such as high temperature, pressure or ionizing radiation. Such gratings are ideally suited for energy production applications where there is a requirement for advanced energy system instrumentation and controls that are operable in harsh environments. This paper will present a review of some of the more recent developments. Full article

(This article belongs to the Special Issue Optical Fiber Sensors 2012)

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11 pages, 351 KiB

Open AccessArticle

The Effect of Direction on Cursor Moving Kinematics

by Ling-Fu Meng¹, Hsin-Yung Chen^1,*, Chiu-Ping Lu¹, Ming-Chung Chen² and Chi-Nung Chu³

¹ Department of Occupational Therapy, Institute of Clinical Behavioral Science, Chang Gung University, No. 259, Wen-Hwa 1st Road, Kwei-Shan, Taoyuan 333, Taiwan

² Department of Special Education, National Chiayi University, No. 300, Syuefu Road, Chiayi 600, Taiwan

³ Department of Information Management, China University of Technology, No. 56, Section 3, Xinglong Road, Wunshan District, Taipei 116, Taiwan

Sensors 2012, 12(2), 1919-1929; https://doi.org/10.3390/s120201919 - 10 Feb 2012

Cited by 1 | Viewed by 6779

Abstract

There have been only few studies to substantiate the kinematic characteristics of cursor movement. In this study, a quantitative experimental research method was used to explore the effect of moving direction on the kinematics of cursor movement in 24 typical young persons using [...] Read more.

There have been only few studies to substantiate the kinematic characteristics of cursor movement. In this study, a quantitative experimental research method was used to explore the effect of moving direction on the kinematics of cursor movement in 24 typical young persons using our previously developed computerized measuring program. The results of multiple one way repeated measures ANOVAs and post hoc LSD tests demonstrated that the moving direction had effects on average velocity, movement time, movement unit and peak velocity. Moving leftward showed better efficiency than moving rightward, upward and downward from the kinematic evidences such as velocity, movement unit and time. Moreover, the unique pattern of the power spectral density (PSD) of velocity (strategy for power application) explained why the smoothness was still maintained while moving leftward even under an unstable situation with larger momentum. Moreover, the information from this cursor moving study can guide us to relocate the toolbars and icons in the window interface, especially for individuals with physical disabilities whose performances are easily interrupted while controlling the cursor in specific directions. Full article

(This article belongs to the Section Physical Sensors)

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20 pages, 1452 KiB

Open AccessArticle

Sunlight Intensity Based Global Positioning System for Near-Surface Underwater Sensors

by Javier V. Gómez¹, Frode E. Sandnes^2,* and Borja Fernández³

¹ Department of Systems and Automation, Carlos III University of Madrid, Avda. de la Universidad 30, 28911 Leganés, Madrid, Spain

² Institute of Information Technology, Faculty of Technology, Art and Design, Oslo and Akershus University College of Applied Sciences, P.O. Box 4, St. Olavs plass, N-0130 Oslo, Norway

³ Department of Computer Science, Rey Juan Carlos University of Madrid, Calle Tulipán s/n, 28933 Móstoles, Madrid, Spain

Sensors 2012, 12(2), 1930-1949; https://doi.org/10.3390/s120201930 - 10 Feb 2012

Cited by 9 | Viewed by 11951

Abstract

Water monitoring is important in domains including documenting climate change, weather prediction and fishing. This paper presents a simple and energy efficient localization strategy for near surface buoy based sensors. Sensors can be dropped randomly in the ocean and thus self-calibrate in terms [...] Read more.

Water monitoring is important in domains including documenting climate change, weather prediction and fishing. This paper presents a simple and energy efficient localization strategy for near surface buoy based sensors. Sensors can be dropped randomly in the ocean and thus self-calibrate in terms of geographic location such that geo-tagged observations of water quality can be made without the need for costly and energy consuming GPS-hardware. The strategy is based on nodes with an accurate clock and light sensors that can regularly sample the level of light intensity. The measurements are fitted into a celestial model of the earth motion around the sun. By identifying the trajectory of the sun across the skies one can accurately determine sunrise and sunset times, and thus extract the longitude and latitude of the sensor. Unlike previous localization techniques for underwater sensors, the current approach does not rely on stationary or mobile reference points. Full article

(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks)

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17 pages, 2070 KiB

Open AccessArticle

Electrical Model of a Carbon-Polymer Composite (CPC) Collision Detector

by Karl Kruusamäe^*

, Andres Punning and Alvo Aabloo

IMS Lab, Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia

Sensors 2012, 12(2), 1950-1966; https://doi.org/10.3390/s120201950 - 10 Feb 2012

Cited by 11 | Viewed by 8410

Abstract

We present a study of an electrical model of electromechanically active carbon-polymer composite (CPC) with carbide-derived carbon (CDC) electrodes. The major focus is on investigation of surface electrode behavior upon external bending of the material. We show that electrical impedance measured from the [...] Read more.

We present a study of an electrical model of electromechanically active carbon-polymer composite (CPC) with carbide-derived carbon (CDC) electrodes. The major focus is on investigation of surface electrode behavior upon external bending of the material. We show that electrical impedance measured from the surface of the CDC-based CPC can be used to determine the curvature of the material and, hence, the tip displacement of a CPC laminate in a cantilever configuration. It is also shown that by measuring surface signals in the process of an actuator’s work-cycle, we obtain a self-sensing collision-detecting CPC actuator that can be considered as a counterpart of biomimetic vibrissae. Full article

(This article belongs to the Special Issue Biomimetic Sensors, Actuators and Integrated Systems)

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23 pages, 1178 KiB

Open AccessArticle

Secure Cooperation of Autonomous Mobile Sensors Using an Underwater Acoustic Network

by Andrea Caiti¹, Vincenzo Calabrò¹, Gianluca Dini², Angelica Lo Duca² and Andrea Munafò^1,*

¹ Department of Energy and Systems Engineering, Inter-University Center on Integrated System for the Marine Environment, Interdepartmental Research Center ”E.Piaggio”, University of Pisa, Largo L. Lazzarino, 1, Pisa 56126, Italy

² Department of Information Engineering, Inter-university center on Integrated System for the Marine Environment, Interdepartmental Research Center ”E.Piaggio”, University of Pisa, Largo L. Lazzarino, 1, Pisa 56126, Italy

Sensors 2012, 12(2), 1967-1989; https://doi.org/10.3390/s120201967 - 10 Feb 2012

Cited by 50 | Viewed by 10642

Abstract

Methodologies and algorithms are presented for the secure cooperation of a team of autonomous mobile underwater sensors, connected through an acoustic communication network, within surveillance and patrolling applications. In particular, the work proposes a cooperative algorithm in which the mobile underwater sensors (installed [...] Read more.

Methodologies and algorithms are presented for the secure cooperation of a team of autonomous mobile underwater sensors, connected through an acoustic communication network, within surveillance and patrolling applications. In particular, the work proposes a cooperative algorithm in which the mobile underwater sensors (installed on Autonomous Underwater Vehicles—AUVs) respond to simple local rules based on the available information to perform the mission and maintain the communication link with the network (behavioral approach). The algorithm is intrinsically robust: with loss of communication among the vehicles the coverage performance (i.e., the mission goal) is degraded but not lost. The ensuing form of graceful degradation provides also a reactive measure against Denial of Service. The cooperative algorithm relies on the fact that the available information from the other sensors, though not necessarily complete, is trustworthy. To ensure trustworthiness, a security suite has been designed, specifically oriented to the underwater scenario, and in particular with the goal of reducing the communication overhead introduced by security in terms of number and size of messages. The paper gives implementation details on the integration between the security suite and the cooperative algorithm and provides statistics on the performance of the system as collected during the UAN project sea trial held in Trondheim, Norway, in May 2011. Full article

(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks)

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15 pages, 1973 KiB

Open AccessArticle

Robust Kernel-Based Tracking with Multiple Subtemplates in Vision Guidance System

by Yuzhuang Yan^*, Xinsheng Huang, Wanying Xu and Lurong Shen

College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha 410073, China

Sensors 2012, 12(2), 1990-2004; https://doi.org/10.3390/s120201990 - 10 Feb 2012

Cited by 7 | Viewed by 6493

Abstract

The mean shift algorithm has achieved considerable success in target tracking due to its simplicity and robustness. However, the lack of spatial information may result in its failure to get high tracking precision. This might be even worse when the target is scale [...] Read more.

The mean shift algorithm has achieved considerable success in target tracking due to its simplicity and robustness. However, the lack of spatial information may result in its failure to get high tracking precision. This might be even worse when the target is scale variant and the sequences are gray-levels. This paper presents a novel multiple subtemplates based tracking algorithm for the terminal guidance application. By applying a separate tracker to each subtemplate, it can handle more complicated situations such as rotation, scaling, and partial coverage of the target. The innovations include: (1) an optimal subtemplates selection algorithm is designed, which ensures that the selected subtemplates maximally represent the information of the entire template while having the least mutual redundancy; (2) based on the serial tracking results and the spatial constraint prior to those subtemplates, a Gaussian weighted voting method is proposed to locate the target center; (3) the optimal scale factor is determined by maximizing the voting results among the scale searching layers, which avoids the complicated threshold setting problem. Experiments on some videos with static scenes show that the proposed method greatly improves the tracking accuracy compared to the original mean shift algorithm. Full article

(This article belongs to the Section Physical Sensors)

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13 pages, 1148 KiB

Open AccessArticle

A Method Based on Multi-Sensor Data Fusion for Fault Detection of Planetary Gearboxes

by Yaguo Lei^1,2,*, Jing Lin¹, Zhengjia He¹ and Detong Kong¹

¹ State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, No. 28 Xianning West Road, Xi’an 710049, China

² State Key Laboratory of Mechanical Transmission, Chongqing University, No. 174 Shazhengjie, Chongqing 400044, China

Sensors 2012, 12(2), 2005-2017; https://doi.org/10.3390/s120202005 - 10 Feb 2012

Cited by 104 | Viewed by 11872

Abstract

Studies on fault detection and diagnosis of planetary gearboxes are quite limited compared with those of fixed-axis gearboxes. Different from fixed-axis gearboxes, planetary gearboxes exhibit unique behaviors, which invalidate fault diagnosis methods that work well for fixed-axis gearboxes. It is a fact that [...] Read more.

Studies on fault detection and diagnosis of planetary gearboxes are quite limited compared with those of fixed-axis gearboxes. Different from fixed-axis gearboxes, planetary gearboxes exhibit unique behaviors, which invalidate fault diagnosis methods that work well for fixed-axis gearboxes. It is a fact that for systems as complex as planetary gearboxes, multiple sensors mounted on different locations provide complementary information on the health condition of the systems. On this basis, a fault detection method based on multi-sensor data fusion is introduced in this paper. In this method, two features developed for planetary gearboxes are used to characterize the gear health conditions, and an adaptive neuro-fuzzy inference system (ANFIS) is utilized to fuse all features from different sensors. In order to demonstrate the effectiveness of the proposed method, experiments are carried out on a planetary gearbox test rig, on which multiple accelerometers are mounted for data collection. The comparisons between the proposed method and the methods based on individual sensors show that the former achieves much higher accuracies in detecting planetary gearbox faults. Full article

(This article belongs to the Section Physical Sensors)

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8 pages, 159 KiB

Open AccessArticle

Highly Sensitive Detection of Naphthalene in Solvent Vapor Using a Functionalized PBG Refractive Index Sensor

by Maiko Girschikofsky^1,*, Manuel Rosenberger¹, Stefan Belle¹, Malte Brutschy², Siegfried R. Waldvogel² and Ralf Hellmann¹

¹ University of Applied Sciences Aschaffenburg, Würzburger Straße 45, D-63743 Aschaffenburg, Germany

² Institute of Organic Chemistry, Johannes Gutenberg-University Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany

Sensors 2012, 12(2), 2018-2025; https://doi.org/10.3390/s120202018 - 13 Feb 2012

Cited by 24 | Viewed by 8844

Abstract

We report an optical refractive index sensor system based on a planar Bragg grating which is functionalized by substituted γ-cyclodextrin to determine low concentrations of naphthalene in solvent vapor. The sensor system exhibits a quasi-instantaneous shift of the Bragg wavelength and is therefore [...] Read more.

We report an optical refractive index sensor system based on a planar Bragg grating which is functionalized by substituted γ-cyclodextrin to determine low concentrations of naphthalene in solvent vapor. The sensor system exhibits a quasi-instantaneous shift of the Bragg wavelength and is therefore capable for online detection. The overall shift of the Bragg wavelength reveals a linear relationship to the analyte concentration with a gradient of 12.5 ± 1.5 pm/ppm. Due to the spectral resolution and repeatability of the interrogation system, this corresponds to acquisition steps of 80 ppb. Taking into account the experimentally detected signal noise a minimum detection limit of 0.48 ± 0.05 ppm is deduced. Full article

(This article belongs to the Section Chemical Sensors)

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36 pages, 680 KiB

Open AccessReview

Localization Algorithms of Underwater Wireless Sensor Networks: A Survey

by Guangjie Han^1,2,*

, Jinfang Jiang^1,2, Lei Shu³, Yongjun Xu⁴ and Feng Wang⁵

¹ Department of Information and Communication Systems, Hohai University, 200 North Jinling Road, Changzhou 213022, China

² Changzhou Key Laboratory of Sensor Networks and Environmental Sensing, Changzhou 213022, China

³ Department of Multimedia Engineering, Graduate School of Information Science and Technology, Osaka University, 1-1 Yamadaoka, Suita, Osaka 565-0871, Japan

⁴ Institute of Computing Technology, Chinese Academy of Sciences, No. 6 Kexueyuan South Road Zhongguancun, Beijing 100190, China

⁵ Naval Academy of Armament, Beijing 100161, China

Sensors 2012, 12(2), 2026-2061; https://doi.org/10.3390/s120202026 - 13 Feb 2012

Cited by 178 | Viewed by 17729

Abstract

In Underwater Wireless Sensor Networks (UWSNs), localization is one of most important technologies since it plays a critical role in many applications. Motivated by widespread adoption of localization, in this paper, we present a comprehensive survey of localization algorithms. First, we classify localization [...] Read more.

In Underwater Wireless Sensor Networks (UWSNs), localization is one of most important technologies since it plays a critical role in many applications. Motivated by widespread adoption of localization, in this paper, we present a comprehensive survey of localization algorithms. First, we classify localization algorithms into three categories based on sensor nodes’ mobility: stationary localization algorithms, mobile localization algorithms and hybrid localization algorithms. Moreover, we compare the localization algorithms in detail and analyze future research directions of localization algorithms in UWSNs. Full article

(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks)

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26 pages, 420 KiB

Open AccessArticle

Architecture and Protocol of a Semantic System Designed for Video Tagging with Sensor Data in Mobile Devices

by Elsa Macias¹, Jaime Lloret^2,*

, Alvaro Suarez¹ and Miguel Garcia²

¹ Grupo de Arquitectura y Concurrencia (GAC), Departamento de Ingeniería Telemática, Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira, 35017, Las Palmas de Gran Canaria (Gran Canaria), Spain

² Instituto de Investigación Para la Gestión Integrada de Zonas Costeras, Universidad Politécnica de Valencia, Camino Vera, s/n, 46022, Valencia, Spain

Sensors 2012, 12(2), 2062-2087; https://doi.org/10.3390/s120202062 - 14 Feb 2012

Cited by 8 | Viewed by 10756

Abstract

Current mobile phones come with several sensors and powerful video cameras. These video cameras can be used to capture good quality scenes, which can be complemented with the information gathered by the sensors also embedded in the phones. For example, the surroundings of [...] Read more.

Current mobile phones come with several sensors and powerful video cameras. These video cameras can be used to capture good quality scenes, which can be complemented with the information gathered by the sensors also embedded in the phones. For example, the surroundings of a beach recorded by the camera of the mobile phone, jointly with the temperature of the site can let users know via the Internet if the weather is nice enough to swim. In this paper, we present a system that tags the video frames of the video recorded from mobile phones with the data collected by the embedded sensors. The tagged video is uploaded to a video server, which is placed on the Internet and is accessible by any user. The proposed system uses a semantic approach with the stored information in order to make easy and efficient video searches. Our experimental results show that it is possible to tag video frames in real time and send the tagged video to the server with very low packet delay variations. As far as we know there is not any other application developed as the one presented in this paper. Full article

(This article belongs to the Special Issue Ubiquitous Sensing)

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30 pages, 4988 KiB

Open AccessArticle

Investigation of the Transient Behavior of a Cantilever Beam Using PVDF Sensors

by Chien-Ching Ma^1,*, Yu-Hsi Huang² and Shan-Ying Pan¹

¹ Department of Mechanical Engineering, National Taiwan University, Taipei 106, Taiwan

² Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan

Sensors 2012, 12(2), 2088-2117; https://doi.org/10.3390/s120202088 - 14 Feb 2012

Cited by 33 | Viewed by 10258

Abstract

In this paper, a PVDF film sensor was used to measure the transient responses of a cantilever beam subjected to an impact loading. The measurement capability of a PVDF sensor is affected by the area of the PVDF film sensor and the signal [...] Read more.

In this paper, a PVDF film sensor was used to measure the transient responses of a cantilever beam subjected to an impact loading. The measurement capability of a PVDF sensor is affected by the area of the PVDF film sensor and the signal conditioner (charge amplifier). The influences of these effects on the experimental measurements were investigated. The transient responses for the dynamic strain of the beam were measured simultaneously by the PVDF sensor and a conventional strain gauge. The resonant frequencies of the beam were determined by applying the Fast Fourier Transform on transient results in the time domain of the PVDF sensor and the strain gauge. The experimentally measured resonant frequencies from the PVDF sensor and the strain gauge were compared with those predicted from theoretical and FEM numerical calculations. Based on the comparison of the results measured for these two sensors, the PVDF film sensor proved capable of measuring transient responses for dynamic strain, and its sensitivity is better than that of the strain gauge. Furthermore, almost all the resonant frequencies can be obtained from the results of transient responses for PVDF film. Full article

(This article belongs to the Section Physical Sensors)

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18 pages, 1803 KiB

Open AccessArticle

Experimental Assessment of Different Receiver Structures for Underwater Acoustic Communications over Multipath Channels

by Guosong Zhang^*, Jens M. Hovem and Hefeng Dong

Department of Electronics and Telecommunications, Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway

Sensors 2012, 12(2), 2118-2135; https://doi.org/10.3390/s120202118 - 14 Feb 2012

Cited by 6 | Viewed by 8462

Abstract

Underwater communication channels are often complicated, and in particular multipath propagation may cause intersymbol interference (ISI). This paper addresses how to remove ISI, and evaluates the performance of three different receiver structures and their implementations. Using real data collected in a high-frequency (10–14 [...] Read more.

Underwater communication channels are often complicated, and in particular multipath propagation may cause intersymbol interference (ISI). This paper addresses how to remove ISI, and evaluates the performance of three different receiver structures and their implementations. Using real data collected in a high-frequency (10–14 kHz) field experiment, the receiver structures are evaluated by off-line data processing. The three structures are multichannel decision feedback equalizer (DFE), passive time reversal receiver (passive-phase conjugation (PPC) with a single channel DFE), and the joint PPC with multichannel DFE. In sparse channels, dominant arrivals represent the channel information, and the matching pursuit (MP) algorithm which exploits the channel sparseness has been investigated for PPC processing. In the assessment, it is found that: (1) it is advantageous to obtain spatial gain using the adaptive multichannel combining scheme; and (2) the MP algorithm improves the performance of communications using PPC processing. Full article

(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks)

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16 pages, 960 KiB

Open AccessReview

Waveguide-Mode Sensors as Aptasensors

by Subash C. B. Gopinath^*, Koichi Awazu and Makoto Fujimaki^*

Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan

Sensors 2012, 12(2), 2136-2151; https://doi.org/10.3390/s120202136 - 15 Feb 2012

Cited by 45 | Viewed by 9622

Abstract

Aptamers are artificial nucleic acid ligands that can be generated by in vitro selection through partition and amplification. Aptamers can be generated against a wide range of biomolecules through the formation of versatile stem-loop structures. Because aptamers are potential substitutes for antibodies and [...] Read more.

Aptamers are artificial nucleic acid ligands that can be generated by in vitro selection through partition and amplification. Aptamers can be generated against a wide range of biomolecules through the formation of versatile stem-loop structures. Because aptamers are potential substitutes for antibodies and drugs, the development of an aptamer-based sensor (aptasensor) is mandatory for diagnosis. We previously reported that waveguide-mode sensors are useful in the analysis of a wide range of biomolecular interactions, including aptamers. The advantages of the waveguide-mode sensor that we developed include physical and chemical stability and that higher sensitivity can be achieved with ease by perforating the waveguide layer or using colored materials such as dyes or metal nanoparticles as labels. Herein, we provide an overview of the strategies and applications for aptamer-based analyses using waveguide-mode sensors. Full article

(This article belongs to the Special Issue Aptamer-Based Sensors)

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10 pages, 1319 KiB

Open AccessCommunication

Objective Display and Discrimination of Floral Odors from Amorphophallus titanum, Bloomed on Different Dates and at Different Locations, Using an Electronic Nose

by Kouki Fujioka¹

, Mika Shirasu², Yoshinobu Manome^1,3,*, Nobuo Ito⁴, Satoshi Kakishima⁵, Tomohiro Minami⁴, Tadashi Tominaga⁴, Fumio Shimozono⁶, Takeo Iwamoto³, Keiichi Ikeda¹, Kenji Yamamoto⁷, Jin Murata⁵ and Yasuko Tomizawa⁸

¹ Department of Molecular Cell Biology, Institute of DNA Medicine, Jikei University School of Medicine, Tokyo 105-8461, Japan

² Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan

³ Core Research Facilities, Jikei University School of Medicine, Tokyo 105-8461, Japan

⁴ Flower Park Kagoshima, Kagoshima 891-0513, Japan

⁵ Botanical Gardens, the University of Tokyo, Tokyo 112-0001, Japan

⁶ Independent Researcher, Ibusuki, Kagoshima 891-0304, Japan

⁷ National Center for Global Health and Medicine, Tokyo 162-8655, Japan

⁸ Department of Cardiovascular Surgery, Tokyo Women’s Medical University, Tokyo 162-8666, Japan

Sensors 2012, 12(2), 2152-2161; https://doi.org/10.3390/s120202152 - 15 Feb 2012

Cited by 24 | Viewed by 14099

Abstract

As olfactory perceptions vary from person to person, it is difficult to describe smells objectively. In contrast, electronic noses also detect smells with their sensors, but in addition describe those using electronic signals. Here we showed a virtual connection method between a human [...] Read more.

As olfactory perceptions vary from person to person, it is difficult to describe smells objectively. In contrast, electronic noses also detect smells with their sensors, but in addition describe those using electronic signals. Here we showed a virtual connection method between a human nose perceptions and electronic nose responses with the smell of standard gases. In this method, Amorphophallus titanum flowers, which emit a strong carrion smell, could objectively be described using an electronic nose, in a way resembling the skill of sommeliers. We could describe the flower smell to be close to that of a mixture of methyl mercaptan and propionic acid, by calculation of the dilution index from electronic resistances. In other words, the smell resembled that of “decayed cabbage, garlic and pungent sour” with possible descriptors. Additionally, we compared the smells of flowers which bloomed on different dates and at different locations and showed the similarity of odor intensities visually, in standard gas categories. We anticipate our assay to be a starting point for a perceptive connection between our noses and electronic noses. Full article

(This article belongs to the Special Issue Odor Detection: Electronic Nose, Olfactometer, and Advanced Instrumentation)

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13 pages, 366 KiB

Open AccessArticle

A Highly Sensitive CMOS Digital Hall Sensor for Low Magnetic Field Applications

by Yue Xu^1,2, Hong-Bin Pan^1,*, Shu-Zhuan He¹ and Li Li¹

¹ School of Electronic Science & Engineering, Nanjing University, Nanjing 210093, China

² College of Electronic Science & Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210003, China

Sensors 2012, 12(2), 2162-2174; https://doi.org/10.3390/s120202162 - 15 Feb 2012

Cited by 35 | Viewed by 10807

Abstract

Integrated CMOS Hall sensors have been widely used to measure magnetic fields. However, they are difficult to work with in a low magnetic field environment due to their low sensitivity and large offset. This paper describes a highly sensitive digital Hall sensor fabricated [...] Read more.

Integrated CMOS Hall sensors have been widely used to measure magnetic fields. However, they are difficult to work with in a low magnetic field environment due to their low sensitivity and large offset. This paper describes a highly sensitive digital Hall sensor fabricated in 0.18 μm high voltage CMOS technology for low field applications. The sensor consists of a switched cross-shaped Hall plate and a novel signal conditioner. It effectively eliminates offset and low frequency 1/f noise by applying a dynamic quadrature offset cancellation technique. The measured results show the optimal Hall plate achieves a high current related sensitivity of about 310 V/AT. The whole sensor has a remarkable ability to measure a minimum ±2 mT magnetic field and output a digital Hall signal in a wide temperature range from −40 °C to 120 °C. Full article

(This article belongs to the Section Physical Sensors)

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33 pages, 814 KiB

Open AccessArticle

A Survey on Virtualization of Wireless Sensor Networks

by Md. Motaharul Islam¹, Mohammad Mehedi Hassan²

, Ga-Won Lee¹

and Eui-Nam Huh^1,*

¹ Internet Computing and Network Security (ICNS) Laboratory, Department of Computer Engineering, College of Electronics and Information, Kyung Hee University, Yongin-si 446-701, Korea

² Research Chair of Pervasive and Mobile Computing, College of Computer and Information Sciences, King Saud University, P.O. Box 51178, Riyadh 11543, Saudi Arabia

Sensors 2012, 12(2), 2175-2207; https://doi.org/10.3390/s120202175 - 15 Feb 2012

Cited by 92 | Viewed by 15831

Abstract

Wireless Sensor Networks (WSNs) are gaining tremendous importance thanks to their broad range of commercial applications such as in smart home automation, health-care and industrial automation. In these applications multi-vendor and heterogeneous sensor nodes are deployed. Due to strict administrative control over the [...] Read more.

Wireless Sensor Networks (WSNs) are gaining tremendous importance thanks to their broad range of commercial applications such as in smart home automation, health-care and industrial automation. In these applications multi-vendor and heterogeneous sensor nodes are deployed. Due to strict administrative control over the specific WSN domains, communication barriers, conflicting goals and the economic interests of different WSN sensor node vendors, it is difficult to introduce a large scale federated WSN. By allowing heterogeneous sensor nodes in WSNs to coexist on a shared physical sensor substrate, virtualization in sensor network may provide flexibility, cost effective solutions, promote diversity, ensure security and increase manageability. This paper surveys the novel approach of using the large scale federated WSN resources in a sensor virtualization environment. Our focus in this paper is to introduce a few design goals, the challenges and opportunities of research in the field of sensor network virtualization as well as to illustrate a current status of research in this field. This paper also presents a wide array of state-of-the art projects related to sensor network virtualization. Full article

(This article belongs to the Section Sensor Networks)

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11 pages, 648 KiB

Open AccessArticle

Near Infrared Characterization of Hetero-Core Optical Fiber SPR Sensors Coated with Ta₂O₅ Film and Their Applications

by Keiju Takagi^* and Kazuhiro Watanabe

Department of Information Systems Science, Faculty of Engineering, Soka University, 1-236, Tangi-machi, Hachioji-shi, Tokyo 192-8577, Japan

Sensors 2012, 12(2), 2208-2218; https://doi.org/10.3390/s120202208 - 15 Feb 2012

Cited by 28 | Viewed by 9514

Abstract

This paper describes the characteristics of optical fiber sensors with surface plasmon resonance (SPR) at 1,310 nm in which the scattering loss of silica optical fiber is low. SPR operation in the infrared wavelength range is achieved by coating a thin tantalum pentaoxide [...] Read more.

This paper describes the characteristics of optical fiber sensors with surface plasmon resonance (SPR) at 1,310 nm in which the scattering loss of silica optical fiber is low. SPR operation in the infrared wavelength range is achieved by coating a thin tantalum pentaoxide (Ta₂O₅) film. The novelty of this paper lies in the verification of how the hetero-core scheme could be operated as a commercial base candidate in the sense of easy fabrication, sufficient mechanical strength, and significant sensitivity as a liquid detector under the basis of a low loss transmission network in the near infrared wavelength region. The effect of Ta₂O₅ layer thickness has been experimentally revealed in the wavelength region extending to 1,800 nm by using the hetero-core structured optical fiber. SPR characterizations have been made in the wavelength region 1,000–1,300 nm, showing the feasible operation at the near infrared wavelength and the possible practical applications. In addition, the technique developed in this work has been interestingly applied to a multi-point water-detection and a water-level gauge in which tandem-connected SPR sensors system using hetero-core structured fibers were incorporated. The detailed performance characteristics are also shown on these applications. Full article

(This article belongs to the Special Issue Optical Fiber Sensors 2012)

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17 pages, 2109 KiB

Open AccessArticle

Improving Planetary Rover Attitude Estimation via MEMS Sensor Characterization

by Javier Hidalgo^1,*, Pantelis Poulakis², Johan Köhler^2,†, Jaime Del-Cerro¹

and Antonio Barrientos¹

¹ Centro de Automática y Robótica, UPM-CSIC, José Gutiérrez Abascal 2, Madrid 28006, Spain

² Automation and Robotics Section, ESA/ESTEC, Noordwijk 2200 AG, The Netherlands

^† Current address: The Swedish National Space Board, Solna SE-171 04, Sweden

Sensors 2012, 12(2), 2219-2235; https://doi.org/10.3390/s120202219 - 15 Feb 2012

Cited by 17 | Viewed by 10518

Abstract

Micro Electro-Mechanical Systems (MEMS) are currently being considered in the space sector due to its suitable level of performance for spacecrafts in terms of mechanical robustness with low power consumption, small mass and size, and significant advantage in system design and accommodation. However, [...] Read more.

Micro Electro-Mechanical Systems (MEMS) are currently being considered in the space sector due to its suitable level of performance for spacecrafts in terms of mechanical robustness with low power consumption, small mass and size, and significant advantage in system design and accommodation. However, there is still a lack of understanding regarding the performance and testing of these new sensors, especially in planetary robotics. This paper presents what is missing in the field: a complete methodology regarding the characterization and modeling of MEMS sensors with direct application. A reproducible and complete approach including all the intermediate steps, tools and laboratory equipment is described. The process of sensor error characterization and modeling through to the final integration in the sensor fusion scheme is explained with detail. Although the concept of fusion is relatively easy to comprehend, carefully characterizing and filtering sensor information is not an easy task and is essential for good performance. The strength of the approach has been verified with representative tests of novel high-grade MEMS inertia sensors and exemplary planetary rover platforms with promising results. Full article

(This article belongs to the Special Issue Modeling, Testing and Reliability Issues in MEMS Engineering 2011)

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19 pages, 3524 KiB

Open AccessReview

Respiratory Physiology and the Impact of Different Modes of Ventilation on the Photoplethysmographic Waveform

by Aymen A. Alian and Kirk H. Shelley^*

Department of Anesthesiology, Yale University School of Medicine, 333 Cedar Street, P.O. Box 208051, New Haven, CT 06520, USA

Sensors 2012, 12(2), 2236-2254; https://doi.org/10.3390/s120202236 - 16 Feb 2012

Cited by 16 | Viewed by 12461

Abstract

The photoplethysmographic waveform sits at the core of the most used, and arguably the most important, clinical monitor, the pulse oximeter. Interestingly, the pulse oximeter was discovered while examining an artifact during the development of a noninvasive cardiac output monitor. This article will [...] Read more.

The photoplethysmographic waveform sits at the core of the most used, and arguably the most important, clinical monitor, the pulse oximeter. Interestingly, the pulse oximeter was discovered while examining an artifact during the development of a noninvasive cardiac output monitor. This article will explore the response of the pulse oximeter waveform to various modes of ventilation. Modern digital signal processing is allowing for a re-examination of this ubiquitous signal. The effect of ventilation on the photoplethysmographic waveform has long been thought of as a source of artifact. The primary goal of this article is to improve the understanding of the underlying physiology responsible for the observed phenomena, thereby encouraging the utilization of this understanding to develop new methods of patient monitoring. The reader will be presented with a review of respiratory physiology followed by numerous examples of the impact of ventilation on the photoplethysmographic waveform. Full article

(This article belongs to the Special Issue Optical Sensors in Medicine)

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29 pages, 595 KiB

Open AccessReview

Gait Analysis Using Wearable Sensors

by Weijun Tao¹, Tao Liu^2,*, Rencheng Zheng³ and Hutian Feng¹

¹ School of Mechanical Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing 210094, China

² Department of Intelligent Mechanical Systems Engineering, Kochi University of Technology, 185 MIyanokuchi, Tosayamada-Cho, Kami-City, Kochi 782-8502, Japan

³ Nakano Lab, Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan

Sensors 2012, 12(2), 2255-2283; https://doi.org/10.3390/s120202255 - 16 Feb 2012

Cited by 956 | Viewed by 70624

Abstract

Gait analysis using wearable sensors is an inexpensive, convenient, and efficient manner of providing useful information for multiple health-related applications. As a clinical tool applied in the rehabilitation and diagnosis of medical conditions and sport activities, gait analysis using wearable sensors shows great [...] Read more.

Gait analysis using wearable sensors is an inexpensive, convenient, and efficient manner of providing useful information for multiple health-related applications. As a clinical tool applied in the rehabilitation and diagnosis of medical conditions and sport activities, gait analysis using wearable sensors shows great prospects. The current paper reviews available wearable sensors and ambulatory gait analysis methods based on the various wearable sensors. After an introduction of the gait phases, the principles and features of wearable sensors used in gait analysis are provided. The gait analysis methods based on wearable sensors is divided into gait kinematics, gait kinetics, and electromyography. Studies on the current methods are reviewed, and applications in sports, rehabilitation, and clinical diagnosis are summarized separately. With the development of sensor technology and the analysis method, gait analysis using wearable sensors is expected to play an increasingly important role in clinical applications. Full article

(This article belongs to the Section Physical Sensors)

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25 pages, 611 KiB

Open AccessReview

Biomarker Discovery by Novel Sensors Based on Nanoproteomics Approaches

by Noelia Dasilva^1,†, Paula Díez^1,†, Sergio Matarraz¹, María González-González¹, Sara Paradinas², Alberto Orfao¹ and Manuel Fuentes^1,*

¹ Centro de Investigación del Cáncer/IBMCC (USAL/CSIC), Departamento de Medicina and Servicio General de Citometría, University of Salamanca, Salamanca 37007, Spain

² Departamento de Química Analítica, Facultad de Ciencias Químicas, University of Salamanca, Salamanca 37008, Spain

^† These authors contributed equally to this work.

Sensors 2012, 12(2), 2284-2308; https://doi.org/10.3390/s120202284 - 16 Feb 2012

Cited by 54 | Viewed by 11389

Abstract

During the last years, proteomics has facilitated biomarker discovery by coupling high-throughput techniques with novel nanosensors. In the present review, we focus on the study of label-based and label-free detection systems, as well as nanotechnology approaches, indicating their advantages and applications in biomarker [...] Read more.

During the last years, proteomics has facilitated biomarker discovery by coupling high-throughput techniques with novel nanosensors. In the present review, we focus on the study of label-based and label-free detection systems, as well as nanotechnology approaches, indicating their advantages and applications in biomarker discovery. In addition, several disease biomarkers are shown in order to display the clinical importance of the improvement of sensitivity and selectivity by using nanoproteomics approaches as novel sensors. Full article

(This article belongs to the Special Issue Biomarkers and Nanosensors: New Approaches for Biology and Medicine)

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15 pages, 939 KiB

Open AccessArticle

Design and Implementation of an Omni-Directional Underwater Acoustic Micro-Modem Based on a Low-Power Micro-Controller Unit

by Tae-Hee Won and Sung-Joon Park^*

Digital Communications Laboratory, Electronic Engineering, Gangneung-Wonju National University, Gangneung, Gangwon 201-702, Korea

Sensors 2012, 12(2), 2309-2323; https://doi.org/10.3390/s120202309 - 20 Feb 2012

Cited by 29 | Viewed by 12695

Abstract

For decades, underwater acoustic communication has been restricted to the point-to-point long distance applications such as deep sea probes and offshore oil fields. For this reason, previous acoustic modems were typically characterized by high data rates and long working ranges at the expense [...] Read more.

For decades, underwater acoustic communication has been restricted to the point-to-point long distance applications such as deep sea probes and offshore oil fields. For this reason, previous acoustic modems were typically characterized by high data rates and long working ranges at the expense of large size and high power consumption. Recently, as the need for underwater wireless sensor networks (UWSNs) has increased, the research and development of compact and low-power consuming communication devices has become the focus. From the consideration that the requisites of acoustic modems for UWSNs are low power consumption, omni-directional beam pattern, low cost and so on, in this paper, we design and implement an omni-directional underwater acoustic micro-modem satisfying these requirements. In order to execute fast digital domain signal processing and support flexible interfaces with other peripherals, an ARM Cortex-M3 is embedded in the micro-modem. Also, for the realization of small and omni-directional properties, a spherical transducer having a resonant frequency of 70 kHz and a diameter of 34 mm is utilized for the implementation. Physical layer frame format and symbol structure for efficient packet-based underwater communication systems are also investigated. The developed acoustic micro-modem is verified analytically and experimentally in indoor and outdoor environments in terms of functionality and performance. Since the modem satisfies the requirements for use in UWSNs, it could be deployed in a wide range of applications requiring underwater acoustic communication. Full article

(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks)

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16 pages, 548 KiB

Open AccessArticle

A Bioanalytical Platform for Simultaneous Detection and Quantification of Biological Toxins

by Oliver G. Weingart^1,2,*, Hui Gao³, François Crevoisier³, Friedrich Heitger³, Marc-André Avondet² and Hans Sigrist³

¹ Laboratory of Food Microbiology, Institute of Food, Nutrition and Health (IFNH), ETH Zurich, Schmelzbergstrasse 7, 8092 Zurich, Switzerland

² Toxinology Group, SPIEZ LABORATORY, 3700 Spiez, Switzerland

³ Arrayon Biotechnology SA, Jaquet-Droz 1, 2002 Neuchâtel, Switzerland

Sensors 2012, 12(2), 2324-2339; https://doi.org/10.3390/s120202324 - 21 Feb 2012

Cited by 30 | Viewed by 11700

Abstract

Prevalent incidents support the notion that toxins, produced by bacteria, fungi, plants or animals are increasingly responsible for food poisoning or intoxication. Owing to their high toxicity some toxins are also regarded as potential biological warfare agents. Accordingly, control, detection and neutralization of [...] Read more.

Prevalent incidents support the notion that toxins, produced by bacteria, fungi, plants or animals are increasingly responsible for food poisoning or intoxication. Owing to their high toxicity some toxins are also regarded as potential biological warfare agents. Accordingly, control, detection and neutralization of toxic substances are a considerable economic burden to food safety, health care and military biodefense. The present contribution describes a new versatile instrument and related procedures for array-based simultaneous detection of bacterial and plant toxins using a bioanalytical platform which combines the specificity of covalently immobilized capture probes with a dedicated instrumentation and immuno-based microarray analytics. The bioanalytical platform consists of a microstructured polymer slide serving both as support of printed arrays and as incubation chamber. The platform further includes an easy-to-operate instrument for simultaneous slide processing at selectable assay temperature. Cy5 coupled streptavidin is used as unifying fluorescent tracer. Fluorescence image analysis and signal quantitation allow determination of the toxin’s identity and concentration. The system’s performance has been investigated by immunological detection of Botulinum Neurotoxin type A (BoNT/A), Staphylococcal enterotoxin B (SEB), and the plant toxin ricin. Toxins were detectable at levels as low as 0.5–1 ng·mL⁻¹ in buffer or in raw milk. Full article

(This article belongs to the Special Issue Bioassays)

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Sensors, Volume 12, Issue 2 (February 2012) – 65 articles , Pages 1130-2350

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