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Sensors, Volume 13, Issue 1 (January 2013) , Pages 1-1384

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Open AccessReview Nucleic Acids for Ultra-Sensitive Protein Detection
Sensors 2013, 13(1), 1353-1384; https://doi.org/10.3390/s130101353
Received: 21 November 2012 / Revised: 26 December 2012 / Accepted: 28 December 2012 / Published: 21 January 2013
Cited by 21 | Viewed by 4224 | PDF Full-text (1435 KB) | HTML Full-text | XML Full-text
Abstract
Major advancements in molecular biology and clinical diagnostics cannot be brought about strictly through the use of genomics based methods. Improved methods for protein detection and proteomic screening are an absolute necessity to complement to wealth of information offered by novel, high-throughput sequencing [...] Read more.
Major advancements in molecular biology and clinical diagnostics cannot be brought about strictly through the use of genomics based methods. Improved methods for protein detection and proteomic screening are an absolute necessity to complement to wealth of information offered by novel, high-throughput sequencing technologies. Only then will it be possible to advance insights into clinical processes and to characterize the importance of specific protein biomarkers for disease detection or the realization of “personalized medicine”. Currently however, large-scale proteomic information is still not as easily obtained as its genomic counterpart, mainly because traditional antibody-based technologies struggle to meet the stringent sensitivity and throughput requirements that are required whereas mass-spectrometry based methods might be burdened by significant costs involved. However, recent years have seen the development of new biodetection strategies linking nucleic acids with existing antibody technology or replacing antibodies with oligonucleotide recognition elements altogether. These advancements have unlocked many new strategies to lower detection limits and dramatically increase throughput of protein detection assays. In this review, an overview of these new strategies will be given. Full article
(This article belongs to the Section Biosensors)
Open AccessArticle Fluorescent Ratiometric Indicators Based on Cu(II)-Induced Changes in Poly(NIPAM) Microparticle Volume
Sensors 2013, 13(1), 1341-1352; https://doi.org/10.3390/s130101341
Received: 1 December 2012 / Revised: 12 January 2013 / Accepted: 15 January 2013 / Published: 21 January 2013
Cited by 5 | Viewed by 3037 | PDF Full-text (864 KB) | HTML Full-text | XML Full-text
Abstract
Microparticles consisting of the thermal responsive polymer N-isopropyl acrylamide (polyNIPAM), a metal ion-binding ligand and a fluorophore pair that undergoes fluorescence resonance energy transfer (FRET) have been prepared and characterized. Upon the addition of Cu(II), the microparticles swell or contract depending on [...] Read more.
Microparticles consisting of the thermal responsive polymer N-isopropyl acrylamide (polyNIPAM), a metal ion-binding ligand and a fluorophore pair that undergoes fluorescence resonance energy transfer (FRET) have been prepared and characterized. Upon the addition of Cu(II), the microparticles swell or contract depending on whether charge is introduced or neutralized on the polymer backbone. The variation in microparticle morphology is translated into changes in emission of each fluorophore in the FRET pair. By measuring the emission intensity ratio between the FRET pair upon Cu(II) addition, the concentration of metal ion in solution can be quantified. This ratiometric fluorescent indicator is the newest technique in an ongoing effort to use emission spectroscopy to monitor Cu(II) thermodynamic activity in environmental water samples. Full article
(This article belongs to the Section Chemical Sensors)
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Open AccessArticle Low-Loss Hollow Waveguide Fibers for Mid-Infrared Quantum Cascade Laser Sensing Applications
Sensors 2013, 13(1), 1329-1340; https://doi.org/10.3390/s130101329
Received: 19 November 2012 / Revised: 8 January 2013 / Accepted: 9 January 2013 / Published: 21 January 2013
Cited by 30 | Viewed by 3593 | PDF Full-text (2594 KB) | HTML Full-text | XML Full-text
Abstract
We report on single mode optical transmission of hollow core glass waveguides (HWG) coupled with an external cavity mid-IR quantum cascade lasers (QCLs). The QCL mode results perfectly matched to the hybrid HE11 waveguide mode and the higher losses TE-like modes have [...] Read more.
We report on single mode optical transmission of hollow core glass waveguides (HWG) coupled with an external cavity mid-IR quantum cascade lasers (QCLs). The QCL mode results perfectly matched to the hybrid HE11 waveguide mode and the higher losses TE-like modes have efficiently suppressed by the deposited inner dielectric coating. Optical losses down to 0.44 dB/m and output beam divergence of ~5 mrad were measured. Using a HGW fiber with internal core size of 300 µm we obtained single mode laser transmission at 10.54 µm and successful employed it in a quartz enhanced photoacoustic gas sensor setup. Full article
(This article belongs to the Special Issue Laser Sensing and Imaging)
Open AccessArticle Design of the Dual Stone Locating System on an Extracorporeal Shock Wave Lithotriptor
Sensors 2013, 13(1), 1319-1328; https://doi.org/10.3390/s130101319
Received: 13 November 2012 / Revised: 4 January 2013 / Accepted: 17 January 2013 / Published: 21 January 2013
Cited by 9 | Viewed by 2929 | PDF Full-text (476 KB) | HTML Full-text | XML Full-text
Abstract
Extracorporeal Shock Wave Lithotriptors are very popular for the treatment of urinary stones all over the world. They depend basically upon either X-ray fluoroscopy or ultrasound scans to detect the stones before therapy begins. To increase the effectiveness of treatment this study took [...] Read more.
Extracorporeal Shock Wave Lithotriptors are very popular for the treatment of urinary stones all over the world. They depend basically upon either X-ray fluoroscopy or ultrasound scans to detect the stones before therapy begins. To increase the effectiveness of treatment this study took advantage of both X-ray and ultrasound to develop a dual stone locating system with image processing modules. Its functions include the initial stone locating mode with stone detection by fluorescent images and the follow-up automatic stone tracking mode made by constant ultrasound scanning. The authors have integrated both apparatus and present the operating principles for both modes. The system used two in vitro experiments to justify its abilities of stone location in all procedures. Full article
(This article belongs to the Special Issue Medical & Biological Imaging)
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Open AccessReview Low Frequency Electrical and Magnetic Methods for Non-Destructive Analysis of Fiber Dispersion in Fiber Reinforced Cementitious Composites: An Overview
Sensors 2013, 13(1), 1300-1318; https://doi.org/10.3390/s130101300
Received: 22 October 2012 / Revised: 16 January 2013 / Accepted: 19 January 2013 / Published: 21 January 2013
Cited by 10 | Viewed by 2870 | PDF Full-text (856 KB) | HTML Full-text | XML Full-text
Abstract
Non-destructive analysis of fiber dispersion in structural elements made of Fiber Reinforced Concrete (FRC) and Fiber Reinforced Cementitious Composites (FRCCs) plays a significant role in the framework of quality control and performance prediction. In this paper, the research activity of the authors in [...] Read more.
Non-destructive analysis of fiber dispersion in structural elements made of Fiber Reinforced Concrete (FRC) and Fiber Reinforced Cementitious Composites (FRCCs) plays a significant role in the framework of quality control and performance prediction. In this paper, the research activity of the authors in the aforementioned field all over the last lustrum will be reviewed. A method based on the measurement of the inductance of a probe to be placed on the specimen will be presented and its progressive development will be described. Obtained correlation with actual fiber dispersion, as checked by means of destructive methods, as well as with the mechanical performance of the composite will also be presented, in an attempt to address the significance of the method from an engineering application perspective. Full article
(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Italy 2012)
Open AccessArticle Robot Evolutionary Localization Based on Attentive Visual Short-Term Memory
Sensors 2013, 13(1), 1268-1299; https://doi.org/10.3390/s130101268
Received: 22 December 2012 / Revised: 14 January 2013 / Accepted: 14 January 2013 / Published: 21 January 2013
Cited by 3 | Viewed by 3102 | PDF Full-text (3110 KB) | HTML Full-text | XML Full-text
Abstract
Cameras are one of the most relevant sensors in autonomous robots. However, two of their challenges are to extract useful information from captured images, and to manage the small field of view of regular cameras. This paper proposes implementing a dynamic visual memory [...] Read more.
Cameras are one of the most relevant sensors in autonomous robots. However, two of their challenges are to extract useful information from captured images, and to manage the small field of view of regular cameras. This paper proposes implementing a dynamic visual memory to store the information gathered from a moving camera on board a robot, followed by an attention system to choose where to look with this mobile camera, and a visual localization algorithm that incorporates this visual memory. The visual memory is a collection of relevant task-oriented objects and 3D segments, and its scope is wider than the current camera field of view. The attention module takes into account the need to reobserve objects in the visual memory and the need to explore new areas. The visual memory is useful also in localization tasks, as it provides more information about robot surroundings than the current instantaneous image. This visual system is intended as underlying technology for service robot applications in real people’s homes. Several experiments have been carried out, both with simulated and real Pioneer and Nao robots, to validate the system and each of its components in office scenarios. Full article
(This article belongs to the Special Issue New Trends towards Automatic Vehicle Control and Perception Systems)
Open AccessArticle An Aerial-Ground Robotic System for Navigation and Obstacle Mapping in Large Outdoor Areas
Sensors 2013, 13(1), 1247-1267; https://doi.org/10.3390/s130101247
Received: 16 October 2012 / Revised: 24 December 2012 / Accepted: 14 January 2013 / Published: 21 January 2013
Cited by 32 | Viewed by 4418 | PDF Full-text (2769 KB) | HTML Full-text | XML Full-text
Abstract
There are many outdoor robotic applications where a robot must reach a goal position or explore an area without previous knowledge of the environment around it. Additionally, other applications (like path planning) require the use of known maps or previous information of the [...] Read more.
There are many outdoor robotic applications where a robot must reach a goal position or explore an area without previous knowledge of the environment around it. Additionally, other applications (like path planning) require the use of known maps or previous information of the environment. This work presents a system composed by a terrestrial and an aerial robot that cooperate and share sensor information in order to address those requirements. The ground robot is able to navigate in an unknown large environment aided by visual feedback from a camera on board the aerial robot. At the same time, the obstacles are mapped in real-time by putting together the information from the camera and the positioning system of the ground robot. A set of experiments were carried out with the purpose of verifying the system applicability. The experiments were performed in a simulation environment and outdoor with a medium-sized ground robot and a mini quad-rotor. The proposed robotic system shows outstanding results in simultaneous navigation and mapping applications in large outdoor environments. Full article
(This article belongs to the Special Issue New Trends towards Automatic Vehicle Control and Perception Systems)
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Open AccessArticle A Comparative Study on Three Different Transducers for the Measurement of Nonlinear Solitary Waves
Sensors 2013, 13(1), 1231-1246; https://doi.org/10.3390/s130101231
Received: 30 November 2012 / Revised: 28 December 2012 / Accepted: 11 January 2013 / Published: 18 January 2013
Cited by 6 | Viewed by 2695 | PDF Full-text (601 KB) | HTML Full-text | XML Full-text
Abstract
In the last decade there has been an increasing interest in the use of highly- and weakly- nonlinear solitary waves in engineering and physics. Nonlinear solitary waves can form and travel in nonlinear systems such as one-dimensional chains of particles, where they are [...] Read more.
In the last decade there has been an increasing interest in the use of highly- and weakly- nonlinear solitary waves in engineering and physics. Nonlinear solitary waves can form and travel in nonlinear systems such as one-dimensional chains of particles, where they are conventionally generated by the mechanical impact of a striker and are measured either by using thin transducers embedded in between two half-particles or by a force sensor placed at the chain’s base. These waves have a constant spatial wavelength and their speed, amplitude, and duration can be tuned by modifying the particles’ material or size, or the velocity of the striker. In this paper we propose two alternative sensing configurations for the measurements of solitary waves propagating in a chain of spherical particles. One configuration uses piezo rods placed in the chain while the other exploits the magnetostrictive property of ferromagnetic materials. The accuracy of these two sensing systems on the measurement of the solitary wave’s characteristics is assessed by comparing experimental data to the numerical prediction of a discrete particle model and to the experimental measurements obtained by means of a conventional transducer. The results show very good agreement and the advantages and limitations of the new sensors are discussed. Full article
(This article belongs to the Special Issue Piezoelectric Sensors and Actuators)
Open AccessArticle A Network Access Control Framework for 6LoWPAN Networks
Sensors 2013, 13(1), 1210-1230; https://doi.org/10.3390/s130101210
Received: 30 November 2012 / Revised: 8 January 2013 / Accepted: 16 January 2013 / Published: 18 January 2013
Cited by 14 | Viewed by 3376 | PDF Full-text (294 KB) | HTML Full-text | XML Full-text
Abstract
Low power over wireless personal area networks (LoWPAN), in particular wireless sensor networks, represent an emerging technology with high potential to be employed in critical situations like security surveillance, battlefields, smart-grids, and in e-health applications. The support of security services in LoWPAN is [...] Read more.
Low power over wireless personal area networks (LoWPAN), in particular wireless sensor networks, represent an emerging technology with high potential to be employed in critical situations like security surveillance, battlefields, smart-grids, and in e-health applications. The support of security services in LoWPAN is considered a challenge. First, this type of networks is usually deployed in unattended environments, making them vulnerable to security attacks. Second, the constraints inherent to LoWPAN, such as scarce resources and limited battery capacity, impose a careful planning on how and where the security services should be deployed. Besides protecting the network from some well-known threats, it is important that security mechanisms be able to withstand attacks that have not been identified before. One way of reaching this goal is to control, at the network access level, which nodes can be attached to the network and to enforce their security compliance. This paper presents a network access security framework that can be used to control the nodes that have access to the network, based on administrative approval, and to enforce security compliance to the authorized nodes. Full article
(This article belongs to the Special Issue Ubiquitous Sensing)
Open AccessArticle Customized Multiwavelets for Planetary Gearbox Fault Detection Based on Vibration Sensor Signals
Sensors 2013, 13(1), 1183-1209; https://doi.org/10.3390/s130101183
Received: 27 November 2012 / Revised: 22 December 2012 / Accepted: 8 January 2013 / Published: 18 January 2013
Cited by 23 | Viewed by 3645 | PDF Full-text (714 KB) | HTML Full-text | XML Full-text
Abstract
Planetary gearboxes exhibit complicated dynamic responses which are more difficult to detect in vibration signals than fixed-axis gear trains because of the special gear transmission structures. Diverse advanced methods have been developed for this challenging task to reduce or avoid unscheduled breakdown and [...] Read more.
Planetary gearboxes exhibit complicated dynamic responses which are more difficult to detect in vibration signals than fixed-axis gear trains because of the special gear transmission structures. Diverse advanced methods have been developed for this challenging task to reduce or avoid unscheduled breakdown and catastrophic accidents. It is feasible to make fault features distinct by using multiwavelet denoising which depends on the feature separation and the threshold denoising. However, standard and fixed multiwavelets are not suitable for accurate fault feature detections because they are usually independent of the measured signals. To overcome this drawback, a method to construct customized multiwavelets based on the redundant symmetric lifting scheme is proposed in this paper. A novel indicator which combines kurtosis and entropy is applied to select the optimal multiwavelets, because kurtosis is sensitive to sharp impulses and entropy is effective for periodic impulses. The improved neighboring coefficients method is introduced into multiwavelet denoising. The vibration signals of a planetary gearbox from a satellite communication antenna on a measurement ship are captured under various motor speeds. The results show the proposed method could accurately detect the incipient pitting faults on two neighboring teeth in the planetary gearbox. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle A Wireless Sensor Network-Based Portable Vehicle Detector Evaluation System
Sensors 2013, 13(1), 1160-1182; https://doi.org/10.3390/s130101160
Received: 16 August 2012 / Revised: 1 December 2012 / Accepted: 31 December 2012 / Published: 17 January 2013
Cited by 14 | Viewed by 4511 | PDF Full-text (1043 KB) | HTML Full-text | XML Full-text
Abstract
In an upcoming smart transportation environment, performance evaluations of existing Vehicle Detection Systems are crucial to maintain their accuracy. The existing evaluation method for Vehicle Detection Systems is based on a wired Vehicle Detection System reference and a video recorder, which must be [...] Read more.
In an upcoming smart transportation environment, performance evaluations of existing Vehicle Detection Systems are crucial to maintain their accuracy. The existing evaluation method for Vehicle Detection Systems is based on a wired Vehicle Detection System reference and a video recorder, which must be operated and analyzed by capable traffic experts. However, this conventional evaluation system has many disadvantages. It is inconvenient to deploy, the evaluation takes a long time, and it lacks scalability and objectivity. To improve the evaluation procedure, this paper proposes a Portable Vehicle Detector Evaluation System based on wireless sensor networks. We describe both the architecture and design of a Vehicle Detector Evaluation System and the implementation results, focusing on the wireless sensor networks and methods for traffic information measurement. With the help of wireless sensor networks and automated analysis, our Vehicle Detector Evaluation System can evaluate a Vehicle Detection System conveniently and objectively. The extensive evaluations of our Vehicle Detector Evaluation System show that it can measure the traffic information such as volume counts and speed with over 98% accuracy. Full article
(This article belongs to the Special Issue Ubiquitous Sensing)
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Open AccessNew Book Received Antenna Systems and Electronic Warfare Applications. Edited by Richard A. Poisel, Artech House, 2012; 1036 pages. Price: £129.00, ISBN 978-1-60807-484-6
Sensors 2013, 13(1), 1158-1159; https://doi.org/10.3390/s130101158
Received: 10 January 2013 / Accepted: 14 January 2013 / Published: 17 January 2013
PDF Full-text (112 KB) | HTML Full-text | XML Full-text
Abstract
This comprehensive book serves as a one-stop resource for practical EW antenna system know-how. Supported with over 700 illustrations and nearly 1,700 equations, this authoritative reference offers you detailed explanations of all the important foundations and aspects of this technology. Moreover, you get [...] Read more.
This comprehensive book serves as a one-stop resource for practical EW antenna system know-how. Supported with over 700 illustrations and nearly 1,700 equations, this authoritative reference offers you detailed explanations of all the important foundations and aspects of this technology. Moreover, you get an in-depth treatment of a wide range of antenna system applications. Full article
(This article belongs to the Section Chemical Sensors)
Open AccessNew Book Received Electronic Warfare Target Location Methods, Second Edition. Edited by Richard A. Poisel, Artech House, 2012; 422 pages. Price: £99.00, ISBN 978-1-60807-523-2
Sensors 2013, 13(1), 1151-1157; https://doi.org/10.3390/s130101151
Received: 10 January 2013 / Accepted: 14 January 2013 / Published: 17 January 2013
PDF Full-text (123 KB) | HTML Full-text | XML Full-text
Abstract
Describing the mathematical development underlying current and classical methods of geolocating electronic systems that are emitting, this newly revised and greatly expanded edition of a classic Artech House book offers practical guidance in electronic warfare target location. The Second Edition features a wealth [...] Read more.
Describing the mathematical development underlying current and classical methods of geolocating electronic systems that are emitting, this newly revised and greatly expanded edition of a classic Artech House book offers practical guidance in electronic warfare target location. The Second Edition features a wealth of additional material including new chapters on time delay estimation, direction finding techniques, and the MUSIC algorithm. This practical resource provides you with critical design information on geolocation algorithms, and establishes the fundamentals of existing algorithms as a launch point for further algorithm development. You gain an in-depth understanding of key target location methods that you can effectively apply to your work in the field. You discover triangulation algorithms that offer a highly efficient way to geolocate targets when the real estate on the sensor systems is adequate to support an antenna array. The book also presents quadratic geolocation techniques that can be implemented with extremely modest antennas — frequently a single dipole or monopole. Moreover, this authoritative volume details methods for geolocating the source of high frequency signals with a single sensor site. Full article
(This article belongs to the Section Chemical Sensors)
Open AccessNew Book Received Introduction to Modern EW Systems. Edited by Andrea De Martino, Artech House, 2012; 417 pages. Price: £119.00, ISBN 978-1-60807-207-1
Sensors 2013, 13(1), 1146-1150; https://doi.org/10.3390/s130101146
Received: 10 January 2013 / Accepted: 14 January 2013 / Published: 17 January 2013
PDF Full-text (121 KB) | HTML Full-text | XML Full-text
Abstract
Master the latest electronic warfare (EW) techniques and technologies related to on-board military platforms with this authoritative resource. You gain expert design guidance on technologies and equipment used to detect and identify emitter threats, giving you an advantage in the never-ending chess game [...] Read more.
Master the latest electronic warfare (EW) techniques and technologies related to on-board military platforms with this authoritative resource. You gain expert design guidance on technologies and equipment used to detect and identify emitter threats, giving you an advantage in the never-ending chess game between sensor guided weapons and EW systems. This unique book offers you deeper insight into EW systems principles of operation and their mathematical descriptions, arming you with better knowledge for your specific design applications. Full article
(This article belongs to the Section Chemical Sensors)
Open AccessArticle Characterization of a New Heat Dissipation Matric Potential Sensor
Sensors 2013, 13(1), 1137-1145; https://doi.org/10.3390/s130101137
Received: 15 October 2012 / Revised: 28 December 2012 / Accepted: 14 January 2013 / Published: 17 January 2013
Cited by 5 | Viewed by 2911 | PDF Full-text (713 KB) | HTML Full-text | XML Full-text
Abstract
Soil moisture sensors can help to reduce the amount of water needed for irrigation. In this paper we describe the PlantCare soil moisture sensor as a new type of heat dissipation sensor, its calibration and the correction for temperature changes. With the PlantCare [...] Read more.
Soil moisture sensors can help to reduce the amount of water needed for irrigation. In this paper we describe the PlantCare soil moisture sensor as a new type of heat dissipation sensor, its calibration and the correction for temperature changes. With the PlantCare sensor it is possible to measure the matric potential indirectly to monitor or control irrigation. This sensor is based on thermal properties of a synthetic felt. After a defined heating phase the cooling time to a threshold temperature is a function of the water content in the synthetic felt. The water content in this porous matrix is controlled by the matric potential in the surrounding soil. Calibration measurements have shown that the sensor is most sensitive to −400 hPa and allows lower sensitivity measurements to −800 hPa. The disturbing effect of the temperature change during the measurement on the cooling time can be corrected by a linear function and the differences among sensors are minimized by a two point calibration. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle Using an Automatic Resistivity Profiler Soil Sensor On-The-Go in Precision Viticulture
Sensors 2013, 13(1), 1121-1136; https://doi.org/10.3390/s130101121
Received: 12 December 2012 / Revised: 3 January 2013 / Accepted: 14 January 2013 / Published: 16 January 2013
Cited by 16 | Viewed by 4444 | PDF Full-text (801 KB) | HTML Full-text | XML Full-text
Abstract
Spatial information on vineyard soil properties can be useful in precision viticulture. In this paper a combination of high resolution soil spatial information of soil electrical resistivity (ER) and ancillary topographic attributes, such as elevation and slope, were integrated to assess the spatial [...] Read more.
Spatial information on vineyard soil properties can be useful in precision viticulture. In this paper a combination of high resolution soil spatial information of soil electrical resistivity (ER) and ancillary topographic attributes, such as elevation and slope, were integrated to assess the spatial variability patterns of vegetative growth and yield of a commercial vineyard (Vitis vinifera L. cv. Tempranillo) located in the wine-producing region of La Rioja, Spain. High resolution continuous geoelectrical mapping was accomplished by an Automatic Resistivity Profiler (ARP) on-the-go sensor with an on-board GPS system; rolling electrodes enabled ER to be measured for a depth of investigation approximately up to 0.5, 1 and 2 m. Regression analysis and cluster analysis algorithm were used to jointly process soil resistivity data, landscape attributes and grapevine variables. ER showed a structured variability that matched well with trunk circumference spatial pattern and yield. Based on resistivity and a simple terrain attribute uniform management units were delineated. Once a spatial relationship to target variables is found, the integration of point measurement with continuous soil resistivity mapping is a useful technique to identify within-plots areas of vineyard with similar status. Full article
(This article belongs to the Special Issue Sensor-Based Technologies and Processes in Agriculture and Forestry)
Open AccessArticle A New Curb Detection Method for Unmanned Ground Vehicles Using 2D Sequential Laser Data
Sensors 2013, 13(1), 1102-1120; https://doi.org/10.3390/s130101102
Received: 12 November 2012 / Revised: 26 December 2012 / Accepted: 9 January 2013 / Published: 16 January 2013
Cited by 25 | Viewed by 3082 | PDF Full-text (877 KB) | HTML Full-text | XML Full-text
Abstract
Curb detection is an important research topic in environment perception, which is an essential part of unmanned ground vehicle (UGV) operations. In this paper, a new curb detection method using a 2D laser range finder in a semi-structured environment is presented. In the [...] Read more.
Curb detection is an important research topic in environment perception, which is an essential part of unmanned ground vehicle (UGV) operations. In this paper, a new curb detection method using a 2D laser range finder in a semi-structured environment is presented. In the proposed method, firstly, a local Digital Elevation Map (DEM) is built using 2D sequential laser rangefinder data and vehicle state data in a dynamic environment and a probabilistic moving object deletion approach is proposed to cope with the effect of moving objects. Secondly, the curb candidate points are extracted based on the moving direction of the vehicle in the local DEM. Finally, the straight and curved curbs are detected by the Hough transform and the multi-model RANSAC algorithm, respectively. The proposed method can detect the curbs robustly in both static and typical dynamic environments. The proposed method has been verified in real vehicle experiments. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessArticle Monolithic Composite “Pressure + Acceleration + Temperature + Infrared” Sensor Using a Versatile Single-Sided “SiN/Poly-Si/Al” Process-Module
Sensors 2013, 13(1), 1085-1101; https://doi.org/10.3390/s130101085
Received: 26 November 2012 / Revised: 27 December 2012 / Accepted: 5 January 2013 / Published: 16 January 2013
Cited by 3 | Viewed by 3676 | PDF Full-text (1284 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
We report a newly developed design/fabrication module with low-cost single-sided “low-stress-silicon-nitride (LS-SiN)/polysilicon (poly-Si)/Al” process for monolithic integration of composite sensors for sensing-network-node applications. A front-side surface-/bulk-micromachining process on a conventional Si-substrate is developed, featuring a multifunctional SiN/poly-Si/Al layer design for diverse sensing functions. [...] Read more.
We report a newly developed design/fabrication module with low-cost single-sided “low-stress-silicon-nitride (LS-SiN)/polysilicon (poly-Si)/Al” process for monolithic integration of composite sensors for sensing-network-node applications. A front-side surface-/bulk-micromachining process on a conventional Si-substrate is developed, featuring a multifunctional SiN/poly-Si/Al layer design for diverse sensing functions. The first “pressure + acceleration + temperature + infrared” (PATIR) composite sensor with the chip size of 2.5 mm × 2.5 mm is demonstrated. Systematic theoretical design and analysis methods are developed. The diverse sensing components include a piezoresistive absolute-pressure sensor (up to 700 kPa, with a sensitivity of 49 mV/MPa under 3.3 V supplied voltage), a piezoresistive accelerometer (±10 g, with a sensitivity of 66 μV/g under 3.3 V and a −3 dB bandwidth of 780 Hz), a thermoelectric infrared detector (with a responsivity of 45 V/W and detectivity of 3.6 × 107 cm·Hz1/2/W) and a thermistor (−25–120 °C). This design/fabrication module concept enables a low-cost monolithically-integrated “multifunctional-library” technique. It can be utilized as a customizable tool for versatile application-specific requirements, which is very useful for small-size, low-cost, large-scale sensing-network node developments. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessArticle Development of a Portable Taste Sensor with a Lipid/Polymer Membrane
Sensors 2013, 13(1), 1076-1084; https://doi.org/10.3390/s130101076
Received: 14 December 2012 / Revised: 14 January 2013 / Accepted: 14 January 2013 / Published: 16 January 2013
Cited by 21 | Viewed by 3833 | PDF Full-text (303 KB) | HTML Full-text | XML Full-text
Abstract
We have developed a new portable taste sensor with a lipid/polymer membrane and conducted experiments to evaluate the sensor’s performance. The fabricated sensor consists of a taste sensor chip (40 mm × 26 mm × 2.2 mm) with working and reference electrodes and [...] Read more.
We have developed a new portable taste sensor with a lipid/polymer membrane and conducted experiments to evaluate the sensor’s performance. The fabricated sensor consists of a taste sensor chip (40 mm × 26 mm × 2.2 mm) with working and reference electrodes and a portable sensor device (80 mm × 25 mm × 20 mm). The working electrode consists of a taste-sensing site comprising a poly(hydroxyethyl)methacrylate (pHEMA) hydrogel layer with KCl as the electrolyte layer and a lipid/polymer membrane as the taste sensing element. The reference electrode comprises a polyvinyl chloride (PVC) membrane layer with a small hole and a pHEMA layer with KCl. The whole device is the size of a USB memory stick, making it suitable for portable use. The sensor’s response to tannic acid as the standard astringency substance showed good accuracy and reproducibility, and was comparable with the performance of a commercially available taste sensing system. Thus, it is possible for this sensor to be used for in-field evaluations and it can make a significant contribution to the food industry, as well as in various fields of research. Full article
(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2012)
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Open AccessArticle G-Quadruplex DNAzyme Molecular Beacon for Amplified Colorimetric Biosensing of Pseudostellaria heterophylla
Sensors 2013, 13(1), 1064-1075; https://doi.org/10.3390/s130101064
Received: 12 December 2012 / Revised: 4 January 2013 / Accepted: 9 January 2013 / Published: 16 January 2013
Cited by 11 | Viewed by 3207 | PDF Full-text (358 KB) | HTML Full-text | XML Full-text
Abstract
With an internal transcribed spacer of 18 S, 5.8 S and 26 S nuclear ribosomal DNA (nrDNA ITS) as DNA marker, we report a colorimetric approach for authentication of Pseudostellaria heterophylla (PH) and its counterfeit species based on the differentiation of the nrDNA [...] Read more.
With an internal transcribed spacer of 18 S, 5.8 S and 26 S nuclear ribosomal DNA (nrDNA ITS) as DNA marker, we report a colorimetric approach for authentication of Pseudostellaria heterophylla (PH) and its counterfeit species based on the differentiation of the nrDNA ITS sequence. The assay possesses an unlabelled G-quadruplex DNAzyme molecular beacon (MB) probe, employing complementary sequence as biorecognition element and 1:1:1:1 split G-quadruplex halves as reporter. In the absence of target DNA (T-DNA), the probe can shape intermolecular G-quadruplex structures capable of binding hemin to form G-quadruplex-hemin DNAzyme and catalyze the oxidation of ABTS2− to blue-green ABTS•− by H2O2. In the presence of T-DNA, T-DNA can hybridize with the complementary sequence to form a duplex structure, hindering the formation of the G-quadruplex structure and resulting in the loss of the catalytic activity. Consequently, a UV-Vis absorption signal decrease is observed in the ABTS2−-H2O2 system. The “turn-off” assay allows the detection of T-DNA from 1.0 × 10−9 to 3.0 × 10−7 mol·L−1 (R2 = 0.9906), with a low detection limit of 3.1 × 1010 mol·L−1. The present study provides a sensitive and selective method and may serve as a foundation of utilizing the DNAzyme MB sensor for identifying traditional Chinese medicines. Full article
(This article belongs to the Section Biosensors)
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Open AccessArticle A Novel Scheme for DVL-Aided SINS In-Motion Alignment Using UKF Techniques
Sensors 2013, 13(1), 1046-1063; https://doi.org/10.3390/s130101046
Received: 7 November 2012 / Revised: 25 December 2012 / Accepted: 5 January 2013 / Published: 15 January 2013
Cited by 52 | Viewed by 3395 | PDF Full-text (407 KB) | HTML Full-text | XML Full-text
Abstract
In-motion alignment of Strapdown Inertial Navigation Systems (SINS) without any geodetic-frame observations is one of the toughest challenges for Autonomous Underwater Vehicles (AUV). This paper presents a novel scheme for Doppler Velocity Log (DVL) aided SINS alignment using Unscented Kalman Filter (UKF) which [...] Read more.
In-motion alignment of Strapdown Inertial Navigation Systems (SINS) without any geodetic-frame observations is one of the toughest challenges for Autonomous Underwater Vehicles (AUV). This paper presents a novel scheme for Doppler Velocity Log (DVL) aided SINS alignment using Unscented Kalman Filter (UKF) which allows large initial misalignments. With the proposed mechanism, a nonlinear SINS error model is presented and the measurement model is derived under the assumption that large misalignments may exist. Since a priori knowledge of the measurement noise covariance is of great importance to robustness of the UKF, the covariance-matching methods widely used in the Adaptive KF (AKF) are extended for use in Adaptive UKF (AUKF). Experimental results show that the proposed DVL-aided alignment model is effective with any initial heading errors. The performances of the adaptive filtering methods are evaluated with regards to their parameter estimation stability. Furthermore, it is clearly shown that the measurement noise covariance can be estimated reliably by the adaptive UKF methods and hence improve the performance of the alignment. Full article
(This article belongs to the Special Issue New Trends towards Automatic Vehicle Control and Perception Systems)
Open AccessReview A Flexible Sensor Technology for the Distributed Measurement of Interaction Pressure
Sensors 2013, 13(1), 1021-1045; https://doi.org/10.3390/s130101021
Received: 1 November 2012 / Revised: 8 January 2013 / Accepted: 8 January 2013 / Published: 15 January 2013
Cited by 45 | Viewed by 6053 | PDF Full-text (2061 KB) | HTML Full-text | XML Full-text
Abstract
We present a sensor technology for the measure of the physical human-robot interaction pressure developed in the last years at Scuola Superiore Sant’Anna. The system is composed of flexible matrices of opto-electronic sensors covered by a soft silicone cover. This sensory system is [...] Read more.
We present a sensor technology for the measure of the physical human-robot interaction pressure developed in the last years at Scuola Superiore Sant’Anna. The system is composed of flexible matrices of opto-electronic sensors covered by a soft silicone cover. This sensory system is completely modular and scalable, allowing one to cover areas of any sizes and shapes, and to measure different pressure ranges. In this work we present the main application areas for this technology. A first generation of the system was used to monitor human-robot interaction in upper- (NEUROExos; Scuola Superiore Sant’Anna) and lower-limb (LOPES; University of Twente) exoskeletons for rehabilitation. A second generation, with increased resolution and wireless connection, was used to develop a pressure-sensitive foot insole and an improved human-robot interaction measurement systems. The experimental characterization of the latter system along with its validation on three healthy subjects is presented here for the first time. A perspective on future uses and development of the technology is finally drafted. Full article
(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Italy 2012)
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Open AccessArticle Registration of 3D and Multispectral Data for the Study of Cultural Heritage Surfaces
Sensors 2013, 13(1), 1004-1020; https://doi.org/10.3390/s130101004
Received: 13 November 2012 / Revised: 24 December 2012 / Accepted: 7 January 2013 / Published: 15 January 2013
Cited by 12 | Viewed by 2915 | PDF Full-text (11521 KB) | HTML Full-text | XML Full-text
Abstract
We present a technique for the multi-sensor registration of featureless datasets based on the photogrammetric tracking of the acquisition systems in use. This method is developed for the in situ study of cultural heritage objects and is tested by digitizing a small canvas [...] Read more.
We present a technique for the multi-sensor registration of featureless datasets based on the photogrammetric tracking of the acquisition systems in use. This method is developed for the in situ study of cultural heritage objects and is tested by digitizing a small canvas successively with a 3D digitization system and a multispectral camera while simultaneously tracking the acquisition systems with four cameras and using a cubic target frame with a side length of 500 mm. The achieved tracking accuracy is better than 0.03 mm spatially and 0.150 mrad angularly. This allows us to seamlessly register the 3D acquisitions and to project the multispectral acquisitions on the 3D model. Full article
(This article belongs to the Section Physical Sensors)
Open AccessReview Monitoring Ion Activities In and Around Cells Using Ion-Selective Liquid-Membrane Microelectrodes
Sensors 2013, 13(1), 984-1003; https://doi.org/10.3390/s130100984
Received: 3 December 2012 / Revised: 31 December 2012 / Accepted: 2 January 2013 / Published: 15 January 2013
Cited by 9 | Viewed by 3296 | PDF Full-text (460 KB) | HTML Full-text | XML Full-text
Abstract
Determining the effective concentration (i.e., activity) of ions in and around living cells is important to our understanding of the contribution of those ions to cellular function. Moreover, monitoring changes in ion activities in and around cells is informative about the [...] Read more.
Determining the effective concentration (i.e., activity) of ions in and around living cells is important to our understanding of the contribution of those ions to cellular function. Moreover, monitoring changes in ion activities in and around cells is informative about the actions of the transporters and/or channels operating in the cell membrane. The activity of an ion can be measured using a glass microelectrode that includes in its tip a liquid-membrane doped with an ion-selective ionophore. Because these electrodes can be fabricated with tip diameters that are less than 1 μm, they can be used to impale single cells in order to monitor the activities of intracellular ions. This review summarizes the history, theory, and practice of ion-selective microelectrode use and brings together a number of classic and recent examples of their usefulness in the realm of physiological study. Full article
(This article belongs to the Special Issue Ultramicroelectrode Electrochemistry - Theory and Applications)
Open AccessArticle Applications of Flexible Ultrasonic Transducer Array for Defect Detection at 150 °C
Sensors 2013, 13(1), 975-983; https://doi.org/10.3390/s130100975
Received: 22 November 2012 / Revised: 10 January 2013 / Accepted: 10 January 2013 / Published: 15 January 2013
Cited by 11 | Viewed by 3766 | PDF Full-text (810 KB) | HTML Full-text | XML Full-text
Abstract
In this study, the feasibility of using a one dimensional 16-element flexible ultrasonic transducer (FUT) array for nondestructive testing at 150 °C is demonstrated. The FUT arrays were made by a sol-gel sprayed piezoelectric film technology; a PZT composite film was sprayed on [...] Read more.
In this study, the feasibility of using a one dimensional 16-element flexible ultrasonic transducer (FUT) array for nondestructive testing at 150 °C is demonstrated. The FUT arrays were made by a sol-gel sprayed piezoelectric film technology; a PZT composite film was sprayed on a titanium foil of 75 µm thickness. Since the FUT array is flexible, it was attached to a steel pipe with an outer diameter of 89 mm and a wall thickness of 6.5 mm at 150 °C. Using the ultrasonic pulse-echo mode, pipe thickness measurements could be performed. Moreover, using the ultrasonic pulse-echo and pitch-catch modes of each element of FUT array, the defect detection was performed on an Al alloy block of 30 mm thickness with a side-drilled hole (SDH) of f3 mm at 150 °C. In addition, a post-processing algorithm based on the total focusing method was used to process the full matrix of these A-scan signals of each single transmitter and multi-receivers, and then the phase-array image was obtained to indicate this defect- SDH. Both results show the capability of FUT array being operated at 150 °C for the corrosion and defect detections. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessArticle C59N Peapods Sensing the Temperature
Sensors 2013, 13(1), 966-974; https://doi.org/10.3390/s130100966
Received: 29 November 2012 / Revised: 5 January 2013 / Accepted: 14 January 2013 / Published: 15 January 2013
Cited by 2 | Viewed by 2449 | PDF Full-text (576 KB) | HTML Full-text | XML Full-text
Abstract
We report the novel photoresponse of nanodevices made from azafullerene (C59N)-encapsulated single-walled carbon nanotubes (C59[email protected]), so called peapods. The photoconducting properties of a C59[email protected] are measured over a temperature range of 10 to 300 K under a [...] Read more.
We report the novel photoresponse of nanodevices made from azafullerene (C59N)-encapsulated single-walled carbon nanotubes (C59[email protected]), so called peapods. The photoconducting properties of a C59[email protected] are measured over a temperature range of 10 to 300 K under a field-effect transistor configuration. It is found that the photosensitivity of C59[email protected] depends very sensitively on the temperature, making them an attractive candidate as a component of nanothermometers covering a wide temperature range. Our results indicate that it is possible to read the temperature by monitoring the optoelectronics signal of C59[email protected] In particular, sensing low temperatures would become more convenient and easy by giving a simple light pulse. Full article
(This article belongs to the Special Issue Nanotube and Nanowire Sensors)
Open AccessArticle Surface Plasmon Resonance Sensor Based on Polymer Photonic Crystal Fibers with Metal Nanolayers
Sensors 2013, 13(1), 956-965; https://doi.org/10.3390/s130100956
Received: 3 December 2012 / Revised: 31 December 2012 / Accepted: 31 December 2012 / Published: 15 January 2013
Cited by 46 | Viewed by 3065 | PDF Full-text (550 KB) | HTML Full-text | XML Full-text
Abstract
A large-mode-area polymer photonic crystal fiber made of polymethyl methacrylate with the cladding having only one layer of air holes near the edge of the fiber is designed and proposed to be used in surface plasmon resonance sensors. In such sensor, a nanoscale [...] Read more.
A large-mode-area polymer photonic crystal fiber made of polymethyl methacrylate with the cladding having only one layer of air holes near the edge of the fiber is designed and proposed to be used in surface plasmon resonance sensors. In such sensor, a nanoscale metal film and analyte can be deposited on the outer side of the fiber instead of coating or filling in the holes of the conventional PCF, which make the real time detection with high sensitivity easily to realize. Moreover, it is relatively stable to changes of the amount and the diameter of air holes, which is very beneficial for sensor fabrication and sensing applications. Numerical simulation results show that under the conditions of the similar spectral and intensity sensitivity of 8.3 × 10−5–9.4 × 10−5 RIU, the confinement loss can be increased dramatically. Full article
(This article belongs to the Section Physical Sensors)
Open AccessReview Odor Sampling: Techniques and Strategies for the Estimation of Odor Emission Rates from Different Source Types
Sensors 2013, 13(1), 938-955; https://doi.org/10.3390/s130100938
Received: 13 December 2012 / Revised: 8 January 2013 / Accepted: 14 January 2013 / Published: 15 January 2013
Cited by 38 | Viewed by 3238 | PDF Full-text (322 KB) | HTML Full-text | XML Full-text
Abstract
Sampling is one of the main issues pertaining to odor characterization and measurement. The aim of sampling is to obtain representative information on the typical characteristics of an odor source by means of the collection of a suitable volume fraction of the effluent. [...] Read more.
Sampling is one of the main issues pertaining to odor characterization and measurement. The aim of sampling is to obtain representative information on the typical characteristics of an odor source by means of the collection of a suitable volume fraction of the effluent. The most important information about an emission source for odor impact assessment is the so-called Odor Emission Rate (OER), which represents the quantity of odor emitted per unit of time, and is expressed in odor units per second (ou∙s−1). This paper reviews the different odor sampling strategies adopted depending on source type. The review includes an overview of odor sampling regulations and a detailed discussion of the equipment to be used as well as the mathematical considerations to be applied to obtain the OER in relation to the sampled source typology. Full article
Open AccessArticle Quasi-Real Time Estimation of Angular Kinematics Using Single-Axis Accelerometers
Sensors 2013, 13(1), 918-937; https://doi.org/10.3390/s130100918
Received: 9 November 2012 / Revised: 28 December 2012 / Accepted: 5 January 2013 / Published: 15 January 2013
Cited by 9 | Viewed by 3628 | PDF Full-text (800 KB) | HTML Full-text | XML Full-text
Abstract
In human movement modeling, the problem of multi-link kinematics estimation by means of inertial measurement units has been investigated by several authors through efficient sensor fusion algorithms. In this perspective a single inertial measurement unit per link is required. This set-up is not [...] Read more.
In human movement modeling, the problem of multi-link kinematics estimation by means of inertial measurement units has been investigated by several authors through efficient sensor fusion algorithms. In this perspective a single inertial measurement unit per link is required. This set-up is not cost-effective compared with a solution in which a single-axis accelerometer per link is used. In this paper, a novel fast technique is presented for the estimation of the sway angle in a multi-link chain by using a single-axis accelerometer per segment and by setting the boundary conditions through an ad hoc algorithm. The technique, based on the windowing of the accelerometer output, was firstly tested on a mechanical arm equipped with a single-axis accelerometer and a reference encoder. The technique is then tested on a subject performing a squat task for the knee flexion-extension angle evaluation by using two single-axis accelerometers placed on the thigh and shank segments, respectively. A stereo-photogrammetric system was used for validation. RMSEs (mean ± std) are 0.40 ± 0.02° (mean peak-to-peak range of 147.2 ± 4.9°) for the mechanical inverted pendulum and 1.01 ± 0.11° (mean peak-to-peak range of 59.29 ± 2.02°) for the knee flexion-extension angle. Results obtained in terms of RMSE were successfully compared with an Extended Kalman Filter applied to an inertial measurement unit. These results suggest the usability of the proposed algorithm in several fields, from automatic control to biomechanics, and open new opportunities to increase the accuracy of the existing tools for orientation evaluation. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessArticle Evaluation of a 433 MHz Band Body Sensor Network for Biomedical Applications
Sensors 2013, 13(1), 898-917; https://doi.org/10.3390/s130100898
Received: 9 November 2012 / Revised: 13 December 2012 / Accepted: 14 December 2012 / Published: 14 January 2013
Cited by 20 | Viewed by 5992 | PDF Full-text (3867 KB) | HTML Full-text | XML Full-text
Abstract
Body sensor networks (BSN) are an important research topic due to various advantages over conventional measurement equipment. One main advantage is the feasibility to deploy a BSN system for 24/7 health monitoring applications. The requirements for such an application are miniaturization of the [...] Read more.
Body sensor networks (BSN) are an important research topic due to various advantages over conventional measurement equipment. One main advantage is the feasibility to deploy a BSN system for 24/7 health monitoring applications. The requirements for such an application are miniaturization of the network nodes and the use of wireless data transmission technologies to ensure wearability and ease of use. Therefore, the reliability of such a system depends on the quality of the wireless data transmission. At present, most BSNs use ZigBee or other IEEE 802.15.4 based transmission technologies. Here, we evaluated the performance of a wireless transmission system of a novel BSN for biomedical applications in the 433MHz ISM band, called Integrated Posture and Activity NEtwork by Medit Aachen (IPANEMA) BSN. The 433MHz ISM band is used mostly by implanted sensors and thus allows easy integration of such into the BSN. Multiple measurement scenarios have been assessed, including varying antenna orientations, transmission distances and the number of network participants. The mean packet loss rate (PLR) was 0.63% for a single slave, which is comparable to IEEE 802.15.4 BSNs in the proximity of Bluetooth orWiFi networks. Secondly, an enhanced version is evaluated during on-body measurements with five slaves. The mean PLR results show a comparable good performance for measurements on a treadmill (2.5%), an outdoor track (3.4%) and in a climate chamber (1.5%). Full article
(This article belongs to the Section Sensor Networks)
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