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Sensors, Volume 12, Issue 11 (November 2012) – 84 articles , Pages 14232-16007

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25 pages, 3756 KiB  
Article
Performance Analysis of Constrained Loosely Coupled GPS/INS Integration Solutions
by Gianluca Falco 1,*, Garry A. Einicke 2, John T. Malos 2 and Fabio Dovis 3
1 Istituto Superiore Mario Boella, Via P.C. Boggio 61, 10138 Torino, Italy
2 Exploration and Mining, Pullenvale, QLD 4069, Australia
3 Politecnico di Torino, Department of Electronics and Telecommunications, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy
Sensors 2012, 12(11), 15983-16007; https://doi.org/10.3390/s121115983 - 20 Nov 2012
Cited by 60 | Viewed by 10010
Abstract
The paper investigates approaches for loosely coupled GPS/INS integration. Error performance is calculated using a reference trajectory. A performance improvement can be obtained by exploiting additional map information (for example, a road boundary). A constrained solution has been developed and its performance compared [...] Read more.
The paper investigates approaches for loosely coupled GPS/INS integration. Error performance is calculated using a reference trajectory. A performance improvement can be obtained by exploiting additional map information (for example, a road boundary). A constrained solution has been developed and its performance compared with an unconstrained one. The case of GPS outages is also investigated showing how a Kalman filter that operates on the last received GPS position and velocity measurements provides a performance benefit. Results are obtained by means of simulation studies and real data. Full article
(This article belongs to the Section Physical Sensors)
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36 pages, 1158 KiB  
Review
Overview of Micro- and Nano-Technology Tools for Stem Cell Applications: Micropatterned and Microelectronic Devices
by Stefano Cagnin 1,†, Elisa Cimetta 2,†, Carlotta Guiducci 3, Paolo Martini 1 and Gerolamo Lanfranchi 1,*
1 Department of Biology and CRIBI Biotechnology Centre, University of Padova, via U. Bassi 58/B, 35121 Padova, Italy
2 Department of Biomedical Engineering, Columbia University, Vanderbilt Clinic Room 12-234, 630 West 168th Street, New York, NY 10032, USA
3 CLSE IBI-EPFL, Swiss Up Chair on Engineering, Laboratory of Life Sciences Electronics, Institute of Bioengineering, Ecole polytechnique Fédérale de Lausanne BM 2106, Station 17, CH-1015 Lausanne, Switzerland
† These authors contributed equally to this work.
Sensors 2012, 12(11), 15947-15982; https://doi.org/10.3390/s121115947 - 19 Nov 2012
Cited by 19 | Viewed by 13250
Abstract
In the past few decades the scientific community has been recognizing the paramount role of the cell microenvironment in determining cell behavior. In parallel, the study of human stem cells for their potential therapeutic applications has been progressing constantly. The use of advanced [...] Read more.
In the past few decades the scientific community has been recognizing the paramount role of the cell microenvironment in determining cell behavior. In parallel, the study of human stem cells for their potential therapeutic applications has been progressing constantly. The use of advanced technologies, enabling one to mimic the in vivo stem cell microenviroment and to study stem cell physiology and physio-pathology, in settings that better predict human cell biology, is becoming the object of much research effort. In this review we will detail the most relevant and recent advances in the field of biosensors and micro- and nano-technologies in general, highlighting advantages and disadvantages. Particular attention will be devoted to those applications employing stem cells as a sensing element. Full article
(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Italy 2012)
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40 pages, 1451 KiB  
Review
Thiol Reactive Probes and Chemosensors
by Hanjing Peng 1, Weixuan Chen 1, Yunfeng Cheng 1, Lovemore Hakuna 2, Robert Strongin 2 and Binghe Wang 1,*
1 Department of Chemistry and the Center for Diagnostics and Therapeutics, Center for Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30302, USA
2 Department of Chemistry, Portland State University, Portland, OR 97207, USA
Sensors 2012, 12(11), 15907-15946; https://doi.org/10.3390/s121115907 - 19 Nov 2012
Cited by 248 | Viewed by 22002
Abstract
Thiols are important molecules in the environment and in biological processes. Cysteine (Cys), homocysteine (Hcy), glutathione (GSH) and hydrogen sulfide (H2S) play critical roles in a variety of physiological and pathological processes. The selective detection of thiols using reaction-based probes and [...] Read more.
Thiols are important molecules in the environment and in biological processes. Cysteine (Cys), homocysteine (Hcy), glutathione (GSH) and hydrogen sulfide (H2S) play critical roles in a variety of physiological and pathological processes. The selective detection of thiols using reaction-based probes and sensors is very important in basic research and in disease diagnosis. This review focuses on the design of fluorescent and colorimetric probes and sensors for thiol detection. Thiol detection methods include probes and labeling agents based on nucleophilic addition and substitution, Michael addition, disulfide bond or Se-N bond cleavage, metal-sulfur interactions and more. Probes for H2S are based on nucleophilic cyclization, reduction and metal sulfide formation. Thiol probe and chemosensor design strategies and mechanism of action are discussed in this review. Full article
(This article belongs to the Special Issue Synthetic Fluorescent Indicators for Low Molecular Weight Organic Metabolites)
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19 pages, 728 KiB  
Article
A Presence-Based Context-Aware Chronic Stress Recognition System
by Klemen Peternel 1,*, Matevž Pogačnik 1, Rudi Tavčar 2 and Andrej Kos 1
1 Laboratory for Telecommunications, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, 1000 Ljubljana, Slovenia
2 Mirabi Institute, Hrastje 223, 4000 Kranj, Slovenia
Sensors 2012, 12(11), 15888-15906; https://doi.org/10.3390/s121115888 - 16 Nov 2012
Cited by 31 | Viewed by 10480
Abstract
Stressors encountered in daily life may play an important role in personal well-being. Chronic stress can have a serious long-term impact on our physical as well as our psychological health, due to ongoing increased levels of the chemicals released in the ‘fight or [...] Read more.
Stressors encountered in daily life may play an important role in personal well-being. Chronic stress can have a serious long-term impact on our physical as well as our psychological health, due to ongoing increased levels of the chemicals released in the ‘fight or flight’ response. The currently available stress assessment methods are usually not suitable for daily chronic stress measurement. The paper presents a context-aware chronic stress recognition system that addresses this problem. The proposed system obtains contextual data from various mobile sensors and other external sources in order to calculate the impact of ongoing stress. By identifying and visualizing ongoing stress situations of an individual user, he/she is able to modify his/her behavior in order to successfully avoid them. Clinical evaluation of the proposed methodology has been made in parallel by using electrodermal activity sensor. To the best of our knowledge, the system presented herein is the first one that enables recognition of chronic stress situations on the basis of user context. Full article
(This article belongs to the Special Issue Ubiquitous Sensing)
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15 pages, 1154 KiB  
Article
Two Dimensional Array of Piezoresistive Nanomechanical Membrane-Type Surface Stress Sensor (MSS) with Improved Sensitivity
by Genki Yoshikawa 1,*, Terunobu Akiyama 2, Frederic Loizeau 2, Kota Shiba 1, Sebastian Gautsch 2, Tomonobu Nakayama 1, Peter Vettiger 2, Nico F. de Rooij 2 and Masakazu Aono 1
1 International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan
2 Institute of Microengineering (IMT), Ecole Polytechnique Fédérale de Lausanne (EPFL), Neuchâtel CH-2002, Switzerland
Sensors 2012, 12(11), 15873-15887; https://doi.org/10.3390/s121115873 - 16 Nov 2012
Cited by 71 | Viewed by 11760
Abstract
We present a new generation of piezoresistive nanomechanical Membrane-type Surface stress Sensor (MSS) chips, which consist of a two dimensional array of MSS on a single chip. The implementation of several optimization techniques in the design and microfabrication improved the piezoresistive sensitivity by [...] Read more.
We present a new generation of piezoresistive nanomechanical Membrane-type Surface stress Sensor (MSS) chips, which consist of a two dimensional array of MSS on a single chip. The implementation of several optimization techniques in the design and microfabrication improved the piezoresistive sensitivity by 3~4 times compared to the first generation MSS chip, resulting in a sensitivity about ~100 times better than a standard cantilever-type sensor and a few times better than optical read-out methods in terms of experimental signal-to-noise ratio. Since the integrated piezoresistive read-out of the MSS can meet practical requirements, such as compactness and not requiring bulky and expensive peripheral devices, the MSS is a promising transducer for nanomechanical sensing in the rapidly growing application fields in medicine, biology, security, and the environment. Specifically, its system compactness due to the integrated piezoresistive sensing makes the MSS concept attractive for the instruments used in mobile applications. In addition, the MSS can operate in opaque liquids, such as blood, where optical read-out techniques cannot be applied. Full article
(This article belongs to the Special Issue Transducer Systems)
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15 pages, 284 KiB  
Article
Development of Immunoassay Based on Monoclonal Antibody Reacted with the Neonicotinoid Insecticides Clothianidin and Dinotefuran
by Mikiko Uchigashima 1, Eiki Watanabe 2, Shigekazu Ito 1, Seiji Iwasa 3 and Shiro Miyake 1,4,*
1 Research & Development Division, HORIBA, Ltd., Minami-ku, Kyoto 601-8510, Japan
2 National Institute for Agro-Environmental Sciences, Tsukuba, Ibaraki 305-8604, Japan
3 Department of Materials Science, Toyohashi University of Technology, Toyohashi, Aichi 441-8580, Japan
4 Advanced Scientific Technology & Management Research Institute of Kyoto, Shimogyo-ku, Kyoto 600-8813, Japan
Sensors 2012, 12(11), 15858-15872; https://doi.org/10.3390/s121115858 - 15 Nov 2012
Cited by 25 | Viewed by 9169
Abstract
Enzyme-linked immunosorbent assay (ELISA) based on a monoclonal antibody (MoAb) was developed for the neonicotinoid insecticide clothianidin. A new clothianidin hapten (3-[5-(3-methyl-2-nitroguanidinomethyl)-1,3-thiazol-2-ylthio] propionic acid) was synthesized and conjugated to keyhole limpet hemocyanin, and was used for monoclonal antibody preparation. The resulting MoAb CTN-16A3-13 [...] Read more.
Enzyme-linked immunosorbent assay (ELISA) based on a monoclonal antibody (MoAb) was developed for the neonicotinoid insecticide clothianidin. A new clothianidin hapten (3-[5-(3-methyl-2-nitroguanidinomethyl)-1,3-thiazol-2-ylthio] propionic acid) was synthesized and conjugated to keyhole limpet hemocyanin, and was used for monoclonal antibody preparation. The resulting MoAb CTN-16A3-13 was characterized by a direct competitive ELISA (dc-ELISA). The 50% of inhibition concentration value with clothianidin was 4.4 ng/mL, and the working range was 1.5–15 ng/mL. The antibody showed high cross-reactivity (64%) to dinotefuran among the structurally related neonicotinoid insecticides. The recovery examinations of clothianidin for cucumber, tomato and apple showed highly agreement with the spiked concentrations; the recovery rate was between 104% and 124% and the coefficient of variation value was between 1.8% and 15%. Although the recovery rate of the dc-ELISA was slightly higher than that of HPLC analysis, the difference was small enough to accept the dc-ELISA as a useful method for residue analysis of clothianidin in garden crops. Full article
(This article belongs to the Special Issue Bioassays)
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17 pages, 355 KiB  
Review
Textile Materials for the Design of Wearable Antennas: A Survey
by Rita Salvado 1,*, Caroline Loss 1, Ricardo Gonçalves 2 and Pedro Pinho 2
1 Unidade de Investigação Materiais Têxteis e Papeleiros, Universidade da Beira Interior, 6201-001 Covilhã, Portugal
2 Instituto de Telecomunicações, Campus Universitário de Santiago, 3810-135 Aveiro, Portugal
Sensors 2012, 12(11), 15841-15857; https://doi.org/10.3390/s121115841 - 15 Nov 2012
Cited by 359 | Viewed by 20380
Abstract
In the broad context of Wireless Body Sensor Networks for healthcare and pervasive applications, the design of wearable antennas offers the possibility of ubiquitous monitoring, communication and energy harvesting and storage. Specific requirements for wearable antennas are a planar structure and flexible construction [...] Read more.
In the broad context of Wireless Body Sensor Networks for healthcare and pervasive applications, the design of wearable antennas offers the possibility of ubiquitous monitoring, communication and energy harvesting and storage. Specific requirements for wearable antennas are a planar structure and flexible construction materials. Several properties of the materials influence the behaviour of the antenna. For instance, the bandwidth and the efficiency of a planar microstrip antenna are mainly determined by the permittivity and the thickness of the substrate. The use of textiles in wearable antennas requires the characterization of their properties. Specific electrical conductive textiles are available on the market and have been successfully used. Ordinary textile fabrics have been used as substrates. However, little information can be found on the electromagnetic properties of regular textiles. Therefore this paper is mainly focused on the analysis of the dielectric properties of normal fabrics. In general, textiles present a very low dielectric constant that reduces the surface wave losses and increases the impedance bandwidth of the antenna. However, textile materials are constantly exchanging water molecules with the surroundings, which affects their electromagnetic properties. In addition, textile fabrics are porous, anisotropic and compressible materials whose thickness and density might change with low pressures. Therefore it is important to know how these characteristics influence the behaviour of the antenna in order to minimize unwanted effects. This paper presents a survey of the key points for the design and development of textile antennas, from the choice of the textile materials to the framing of the antenna. An analysis of the textile materials that have been used is also presented. Full article
(This article belongs to the Section Sensor Networks)
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14 pages, 824 KiB  
Article
Assessment of Fluorescent Particles for Surface Flow Analysis
by Flavia Tauro 1,2,3, Gabriele Mocio 4, Emiliano Rapiti 1, Salvatore Grimaldi 1,3,4 and Maurizio Porfiri 1,*
1 Department of Mechanical and Aerospace Engineering, Polytechnic Institute of New York University, Brooklyn, NY 11201, USA
2 Dipartimento di Ingegneria Civile, Edile e Ambientale, Sapienza University of Rome, Rome 00184, Italy
3 Honors Center of Italian Universities, Sapienza University of Rome, Rome 00184, Italy
4 Dipartimento per l'Innovazione nei Sistemi Biologici, Agroalimentari e Forestali, University of Tuscia, Viterbo 01100, Italy
Sensors 2012, 12(11), 15827-15840; https://doi.org/10.3390/s121115827 - 14 Nov 2012
Cited by 12 | Viewed by 8134
Abstract
In this paper, a systematic performance assessment of the measurement system for surface flow analysis developed by our group in (Tauro et al., Sensors, 2010) is presented. The system is based on the detection of buoyant fluorescent microspheres through alow-cost apparatus, which incorporates [...] Read more.
In this paper, a systematic performance assessment of the measurement system for surface flow analysis developed by our group in (Tauro et al., Sensors, 2010) is presented. The system is based on the detection of buoyant fluorescent microspheres through alow-cost apparatus, which incorporates light sources to elicit fluorescence response and a digital camera to identify the particles' transit. Experiments are conducted using green fluorescent particles and further tests are executed to evaluate the system performance forred and orange particles varying in emission wavelength, degree of biocompatibility, and cost. The influence of the following parameters on surface flow sensing using fluorescent beads is investigated: (i) distance of the light sources from the water surface, (ii) presence of an ad-hoc filter tuned at the particle emission wavelength, (iii) camera resolution and frame rate, (iv) flow regime, and (v) ambient light. Experimental results are used to inform implementation guidelines for surface flow analysis in natural environments. Full article
(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Italy 2012)
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7 pages, 634 KiB  
Communication
Optical-Based Sensors for Monitoring Corrosion of Reinforcement Rebar via an Etched Cladding Bragg Grating
by Muhammad Rosdi Abu Hassan 1,*, Muhammad Hafiz Abu Bakar 2, Katrina Dambul 1 and Faisal Rafiq Mahamd Adikan 1
1 Department of Electrical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia
2 Wireless and Photonics Networks Research Centre, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
Sensors 2012, 12(11), 15820-15826; https://doi.org/10.3390/s121115820 - 14 Nov 2012
Cited by 62 | Viewed by 7195
Abstract
In this paper, we present the development and testing of an optical-based sensor for monitoring the corrosion of reinforcement rebar. The testing was carried out using an 80% etched-cladding Fibre Bragg grating sensor to monitor the production of corrosion waste in a localized [...] Read more.
In this paper, we present the development and testing of an optical-based sensor for monitoring the corrosion of reinforcement rebar. The testing was carried out using an 80% etched-cladding Fibre Bragg grating sensor to monitor the production of corrosion waste in a localized region of the rebar. Progression of corrosion can be sensed by observing the reflected wavelength shift of the FBG sensor. With the presence of corrosion, the etched-FBG reflected spectrum was shifted by 1.0 nm. In addition, with an increase in fringe pattern and continuously, step-like drop in power of the Bragg reflected spectrum was also displayed. Full article
(This article belongs to the Section Physical Sensors)
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19 pages, 522 KiB  
Article
Monitoring Pest Insect Traps by Means of Low-Power Image Sensor Technologies
by Otoniel López 1, Miguel Martinez Rach 1, Hector Migallon 1, Manuel P. Malumbres 1,*, Alberto Bonastre 2 and Juan J. Serrano 2
1 Department of Physics and Computer Architecturer, Miguel Hernandez University, Ave. Universidad s/n-Ed. Alcudia, 03202 Elche, Spain
2 Department of Computer Engineering, Technical University of Valencia, Camino de Vera s/n, 46021 Valencia, Spain
Sensors 2012, 12(11), 15801-15819; https://doi.org/10.3390/s121115801 - 13 Nov 2012
Cited by 65 | Viewed by 16268
Abstract
Monitoring pest insect populations is currently a key issue in agriculture and forestry protection. At the farm level, human operators typically must perform periodical surveys of the traps disseminated through the field. This is a labor-, time- and cost-consuming activity, in particular for [...] Read more.
Monitoring pest insect populations is currently a key issue in agriculture and forestry protection. At the farm level, human operators typically must perform periodical surveys of the traps disseminated through the field. This is a labor-, time- and cost-consuming activity, in particular for large plantations or large forestry areas, so it would be of great advantage to have an affordable system capable of doing this task automatically in an accurate and a more efficient way. This paper proposes an autonomous monitoring system based on a low-cost image sensor that it is able to capture and send images of the trap contents to a remote control station with the periodicity demanded by the trapping application. Our autonomous monitoring system will be able to cover large areas with very low energy consumption. This issue would be the main key point in our study; since the operational live of the overall monitoring system should be extended to months of continuous operation without any kind of maintenance (i.e., battery replacement). The images delivered by image sensors would be time-stamped and processed in the control station to get the number of individuals found at each trap. All the information would be conveniently stored at the control station, and accessible via Internet by means of available network services at control station (WiFi, WiMax, 3G/4G, etc.). Full article
(This article belongs to the Special Issue Sensor-Based Technologies and Processes in Agriculture and Forestry)
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23 pages, 1424 KiB  
Article
Vehicle Dynamic Prediction Systems with On-Line Identification of Vehicle Parameters and Road Conditions
by Ling-Yuan Hsu and Tsung-Lin Chen *
Department of Mechanical Engineering, National Chiao Tung University, University Road 1001, Hsinchu, Taiwan
Sensors 2012, 12(11), 15778-15800; https://doi.org/10.3390/s121115778 - 13 Nov 2012
Cited by 20 | Viewed by 9948
Abstract
This paper presents a vehicle dynamics prediction system, which consists of a sensor fusion system and a vehicle parameter identification system. This sensor fusion system can obtain the six degree-of-freedom vehicle dynamics and two road angles withoutusing a vehicle model. The vehicle parameter [...] Read more.
This paper presents a vehicle dynamics prediction system, which consists of a sensor fusion system and a vehicle parameter identification system. This sensor fusion system can obtain the six degree-of-freedom vehicle dynamics and two road angles withoutusing a vehicle model. The vehicle parameter identification system uses the vehicle dynamics from the sensor fusion system to identify ten vehicle parameters in real time, includingvehicle mass, moment of inertial, and road friction coefficients. With above two systems, the future vehicle dynamics is predicted by using a vehicle dynamics model, obtained from the parameter identification system, to propagate with time the current vehicle state values, obtained from the sensor fusion system. Comparing with most existing literatures in this field, the proposed approach improves the prediction accuracy both by incorporating more vehicle dynamics to the prediction system and by on-line identification to minimize the vehicle modeling errors. Simulation results show that the proposed method successfully predicts the vehicle dynamics in a left-hand turn event and a rollover event. The prediction inaccuracy is 0.51% in a left-hand turn event and 27.3% in a rollover event. Full article
(This article belongs to the Special Issue New Trends towards Automatic Vehicle Control and Perception Systems)
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28 pages, 4047 KiB  
Article
A Neural Network Based Intelligent Predictive Sensor for Cloudiness, Solar Radiation and Air Temperature
by Pedro M. Ferreira 1,2,*,†, João M. Gomes 3, Igor A. C. Martins 3 and António E. Ruano 2,3
1 Algarve Science and Technology Park, Campus de Gambelas, Pav. A5, 8005-139 Faro, Portugal
2 Centre for Intelligent Systems, IDMEC-IST, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal
3 Department of Electronic and Informatics Engineering, University of Algarve, 8005-139, Faro, Portugal
† Current address: Department of Informatics, Faculty of Sciences of the University of Lisbon, Edifício C6 Piso 3, Campo Grande, 1749-016 Lisboa, Portugal
Sensors 2012, 12(11), 15750-15777; https://doi.org/10.3390/s121115750 - 12 Nov 2012
Cited by 28 | Viewed by 7934 | Correction
Abstract
Accurate measurements of global solar radiation and atmospheric temperature,as well as the availability of the predictions of their evolution over time, are importantfor different areas of applications, such as agriculture, renewable energy and energymanagement, or thermal comfort in buildings. For this reason, an [...] Read more.
Accurate measurements of global solar radiation and atmospheric temperature,as well as the availability of the predictions of their evolution over time, are importantfor different areas of applications, such as agriculture, renewable energy and energymanagement, or thermal comfort in buildings. For this reason, an intelligent, light-weightand portable sensor was developed, using artificial neural network models as the time-seriespredictor mechanisms. These have been identified with the aid of a procedure based on themulti-objective genetic algorithm. As cloudiness is the most significant factor affecting thesolar radiation reaching a particular location on the Earth surface, it has great impact on theperformance of predictive solar radiation models for that location. This work also representsone step towards the improvement of such models by using ground-to-sky hemisphericalcolour digital images as a means to estimate cloudiness by the fraction of visible skycorresponding to clouds and to clear sky. The implementation of predictive models inthe prototype has been validated and the system is able to function reliably, providingmeasurements and four-hour forecasts of cloudiness, solar radiation and air temperature. Full article
(This article belongs to the Section Physical Sensors)
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41 pages, 932 KiB  
Review
The Swipe Card Model of Odorant Recognition
by Jennifer C. Brookes 1,*, Andrew P. Horsfield 2,* and A. Marshall Stoneham 3
1 Department of Chemistry and Chemical Biology, Harvard University, Oxford Street, Cambridge, MA 02138, USA
2 Department of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
3 London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH, UK
Sensors 2012, 12(11), 15709-15749; https://doi.org/10.3390/s121115709 - 12 Nov 2012
Cited by 44 | Viewed by 11062
Abstract
Just how we discriminate between the different odours we encounter is notcompletely understood yet. While obviously a matter involving biology, the core issue isa matter for physics: what microscopic interactions enable the receptors in our noses-smallprotein switches—to distinguish scent molecules? We survey what [...] Read more.
Just how we discriminate between the different odours we encounter is notcompletely understood yet. While obviously a matter involving biology, the core issue isa matter for physics: what microscopic interactions enable the receptors in our noses-smallprotein switches—to distinguish scent molecules? We survey what is and is not known aboutthe physical processes that take place when we smell things, highlighting the difficultiesin developing a full understanding of the mechanics of odorant recognition. The maincurrent theories, discussed here, fall into two major groups. One class emphasises thescent molecule's shape, and is described informally as a "lock and key" mechanism. Butthere is another category, which we focus on and which we call "swipe card" theories:the molecular shape must be good enough, but the information that identifies the smellinvolves other factors. One clearly-defined "swipe card" mechanism that we discuss hereis Turin's theory, in which inelastic electron tunnelling is used to discern olfactant vibrationfrequencies. This theory is explicitly quantal, since it requires the molecular vibrations totake in or give out energy only in discrete quanta. These ideas lead to obvious experimentaltests and challenges. We describe the current theory in a form that takes into accountmolecular shape as well as olfactant vibrations. It emerges that this theory can explainmany observations hard to reconcile in other ways. There are still some important gapsin a comprehensive physics-based description of the central steps in odorant recognition. We also discuss how far these ideas carry over to analogous processes involving other smallbiomolecules, like hormones, steroids and neurotransmitters. We conclude with a discussionof possible quantum behaviours in biology more generally, the case of olfaction being justone example. This paper is presented in honour of Prof. Marshall Stoneham who passedaway unexpectedly during its writing. Full article
(This article belongs to the Special Issue Odor Detection: Electronic Nose, Olfactometer, and Advanced Instrumentation)
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20 pages, 1084 KiB  
Article
Impact of High Power Interference Sources in Planning and Deployment of Wireless Sensor Networks and Devices in the 2.4 GHz Frequency Band in Heterogeneous Environments
by Peio López Iturri, Juan Antonio Nazábal, Leire Azpilicueta, Pablo Rodriguez, Miguel Beruete, Carlos Fernández-Valdivielso and Francisco Falcone *
Electrical and Electronic Engineering Department, Universidad Pública de Navarra, 31006 Pamplona, Spain
Sensors 2012, 12(11), 15689-15708; https://doi.org/10.3390/s121115689 - 12 Nov 2012
Cited by 38 | Viewed by 9962
Abstract
In this work, the impact of radiofrequency radiation leakage from microwave ovens and its effect on 802.15.4 ZigBee-compliant wireless sensor networks operating in the 2.4 GHz Industrial Scientific Medical (ISM) band is analyzed. By means of a novel radioplanning approach, based on electromagnetic [...] Read more.
In this work, the impact of radiofrequency radiation leakage from microwave ovens and its effect on 802.15.4 ZigBee-compliant wireless sensor networks operating in the 2.4 GHz Industrial Scientific Medical (ISM) band is analyzed. By means of a novel radioplanning approach, based on electromagnetic field simulation of a microwave oven and determination of equivalent radiation sources applied to an in-house developed 3D ray launching algorithm, estimation of the microwave oven’s power leakage is obtained for the complete volume of an indoor scenario. The magnitude and the variable nature of the interference is analyzed and the impact in the radio link quality in operating wireless sensors is estimated and compared with radio channel measurements as well as packet measurements. The measurement results reveal the importance of selecting an adequate 802.15.4 channel, as well as the Wireless Sensor Network deployment strategy within this type of environment, in order to optimize energy consumption and increase the overall network performance. The proposed method enables one to estimate potential interference effects in devices operating within the 2.4 GHz band in the complete scenario, prior to wireless sensor network deployment, which can aid in achieving the most optimal network topology. Full article
(This article belongs to the Special Issue Ubiquitous Sensing)
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18 pages, 1128 KiB  
Article
A Development Architecture for Serious Games Using BCI (Brain Computer Interface) Sensors
by Yunsick Sung 1, Kyungeun Cho 2,* and Kyhyun Um 2
1 The Department of Computer & Information Science & Engineering, University of Florida, Gainesville, FL 32601, USA
2 Department of Multimedia Engineering, Dongguk University-Seoul, 26 Pildong, 3 Ga, Jung-gu, Seoul 100-715, Korea
Sensors 2012, 12(11), 15671-15688; https://doi.org/10.3390/s121115671 - 12 Nov 2012
Cited by 27 | Viewed by 10149
Abstract
Games that use brainwaves via brain–computer interface (BCI) devices, to improve brain functions are known as BCI serious games. Due to the difficulty of developing BCI serious games, various BCI engines and authoring tools are required, and these reduce the development time and [...] Read more.
Games that use brainwaves via brain–computer interface (BCI) devices, to improve brain functions are known as BCI serious games. Due to the difficulty of developing BCI serious games, various BCI engines and authoring tools are required, and these reduce the development time and cost. However, it is desirable to reduce the amount of technical knowledge of brain functions and BCI devices needed by game developers. Moreover, a systematic BCI serious game development process is required. In this paper, we present a methodology for the development of BCI serious games. We describe an architecture, authoring tools, and development process of the proposed methodology, and apply it to a game development approach for patients with mild cognitive impairment as an example. This application demonstrates that BCI serious games can be developed on the basis of expert-verified theories. Full article
(This article belongs to the Special Issue Ubiquitous Sensing)
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33 pages, 547 KiB  
Article
Robust Observation Detection for Single Object Tracking: Deterministic and Probabilistic Patch-Based Approaches
by Mohd Asyraf Zulkifley 1,*, David Rawlinson 2 and Bill Moran 2
1 Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Malaysia
2 Department of Electrical and Electronic Engineering, The University of Melbourne, VIC 3010, Australia
Sensors 2012, 12(11), 15638-15670; https://doi.org/10.3390/s121115638 - 12 Nov 2012
Cited by 23 | Viewed by 6693
Abstract
In video analytics, robust observation detection is very important as thecontent of the videos varies a lot, especially for tracking implementation. Contraryto the image processing field, the problems of blurring, moderate deformation, lowillumination surroundings, illumination change and homogenous texture are normallyencountered in video [...] Read more.
In video analytics, robust observation detection is very important as thecontent of the videos varies a lot, especially for tracking implementation. Contraryto the image processing field, the problems of blurring, moderate deformation, lowillumination surroundings, illumination change and homogenous texture are normallyencountered in video analytics. Patch-Based Observation Detection (PBOD) is developed toimprove detection robustness to complex scenes by fusing both feature- and template-basedrecognition methods. While we believe that feature-based detectors are more distinctive,however, for finding the matching between the frames are best achieved by a collectionof points as in template-based detectors. Two methods of PBOD—the deterministic andprobabilistic approaches—have been tested to find the best mode of detection. Bothalgorithms start by building comparison vectors at each detected points of interest. Thevectors are matched to build candidate patches based on their respective coordination. Forthe deterministic method, patch matching is done in 2-level test where threshold-basedposition and size smoothing are applied to the patch with the highest correlation value. Forthe second approach, patch matching is done probabilistically by modelling the histogramsof the patches by Poisson distributions for both RGB and HSV colour models. Then,maximum likelihood is applied for position smoothing while a Bayesian approach is appliedfor size smoothing. The result showed that probabilistic PBOD outperforms the deterministicapproach with average distance error of 10.03% compared with 21.03%. This algorithm is best implemented as a complement to other simpler detection methods due to heavyprocessing requirement. Full article
(This article belongs to the Section Physical Sensors)
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10 pages, 375 KiB  
Article
Intracellular ATP Assay of Live Cells Using PTD-Conjugated Luciferase
by Mi-Sook Lee 1,2, Wan-Soon Park 1, Young Han Kim 1, Won Gyeong Ahn 1, Seung-Hae Kwon 1 and Song Her 1,*
1 Division of Bio-Imaging, Chuncheon Center, Korea Basic Science Institute, Chuncheon 200-701, Korea
2 Acupuncture & Meridian Science Research Center, College of Oriental Medicine, Kyung Hee University, Seoul 130-701, Korea
Sensors 2012, 12(11), 15628-15637; https://doi.org/10.3390/s121115628 - 12 Nov 2012
Cited by 23 | Viewed by 17113
Abstract
Luciferase is a sensitive, reliable biological sensor used for measuring ATP. However, its widespread application in drug discovery and toxicology studies has been limited due to unavoidable cell extraction processes, which cause inaccurate measurements of intracellular ATP and obstruct the application of homogenous [...] Read more.
Luciferase is a sensitive, reliable biological sensor used for measuring ATP. However, its widespread application in drug discovery and toxicology studies has been limited due to unavoidable cell extraction processes, which cause inaccurate measurements of intracellular ATP and obstruct the application of homogenous high-throughput screening. Recently, we developed a protein transduction domain-conjugated luciferase (PTD-Luc) for measuring cellular uptake efficacy. In this study, we evaluated the applicability of PTD-Luc to an intracellular ATP assay of live cells. The predominant fluorescence of Alexa 647-PTD-Luc was in the cytosol, whereas the fluorescence of Alexa 647-Luc was visualized surrounding the cell membrane, as confirmed by Western blot analysis. In vitro, PTD-Luc could detect less than 10–9 M ATP, and the correlation between the luciferase activity of PTD-Luc and the ATP content was strong (R = 0.999, p < 0.001). In vivo, luminescence signals of PTD-Luc detected intracellular ATP in as few as 50 HeLa cells, with a strong correlation between luminescence and cell number, suggesting high sensitivity and reliability. Furthermore, two blockers of the glycolytic pathway (2-deoxyglucose and iodoacetic acid) inhibited the signal in a dose-dependent manner, whereas potassium cyanide, an inhibitor of oxidative phosphorylation, had no effect on intracellular ATP in vivo, as seen with the PTD-Luc sensor. These data show that PTD-Luc can directly measure the intracellular ATP content in live cells, allowing real-time kinetic studies, suggesting that it is a promising tool for high-throughput drug screening and cytotoxicity assays. Full article
(This article belongs to the Special Issue Live Cell-Based Sensors)
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29 pages, 677 KiB  
Article
McMAC: Towards a MAC Protocol with Multi-Constrained QoS Provisioning for Diverse Traffic in Wireless Body Area Networks
by Muhammad Mostafa Monowar 1,*, Mohammad Mehedi Hassan 2, Fuad Bajaber 1, Musaed Al-Hussein 2 and Atif Alamri 2
1 Department of Information Technology, Faculty of Computing and Information Technology, King AbdulAziz University, 21589 Jeddah, Saudi Arabia
2 College of Computer and Information Sciences, King Saud University, 11543 Riyadh, Saudi Arabia
Sensors 2012, 12(11), 15599-15627; https://doi.org/10.3390/s121115599 - 12 Nov 2012
Cited by 33 | Viewed by 8204
Abstract
The emergence of heterogeneous applications with diverse requirements forresource-constrained Wireless Body Area Networks (WBANs) poses significant challengesfor provisioning Quality of Service (QoS) with multi-constraints (delay and reliability) while preserving energy efficiency. To address such challenges, this paper proposes McMAC,a MAC protocol with multi-constrained [...] Read more.
The emergence of heterogeneous applications with diverse requirements forresource-constrained Wireless Body Area Networks (WBANs) poses significant challengesfor provisioning Quality of Service (QoS) with multi-constraints (delay and reliability) while preserving energy efficiency. To address such challenges, this paper proposes McMAC,a MAC protocol with multi-constrained QoS provisioning for diverse traffic classes in WBANs. McMAC classifies traffic based on their multi-constrained QoS demands andintroduces a novel superframe structure based on the "transmit-whenever-appropriate" principle, which allows diverse periods for diverse traffic classes according to their respective QoS requirements. Furthermore, a novel emergency packet handling mechanism is proposedto ensure packet delivery with the least possible delay and the highest reliability. McMAC is also modeled analytically, and extensive simulations were performed to evaluate itsperformance. The results reveal that McMAC achieves the desired delay and reliability guarantee according to the requirements of a particular traffic class while achieving energy efficiency. Full article
(This article belongs to the Special Issue Body Sensor Networks for Healthcare and Pervasive Applications)
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41 pages, 817 KiB  
Review
Recent Advances in Integrated Photonic Sensors
by Vittorio M. N. Passaro *, Corrado De Tullio, Benedetto Troia, Mario La Notte, Giovanni Giannoccaro and Francesco De Leonardis
Photonics Research Group, Dipartimento di Elettrotecnica ed Elettronica, Politecnico di Bari, Via Edoardo Orabona 4, 70125 Bari, Italy
Sensors 2012, 12(11), 15558-15598; https://doi.org/10.3390/s121115558 - 9 Nov 2012
Cited by 152 | Viewed by 19013
Abstract
Nowadays, optical devices and circuits are becoming fundamental components in several application fields such as medicine, biotechnology, automotive, aerospace, food quality control, chemistry, to name a few. In this context, we propose a complete review on integrated photonic sensors, with specific attention to [...] Read more.
Nowadays, optical devices and circuits are becoming fundamental components in several application fields such as medicine, biotechnology, automotive, aerospace, food quality control, chemistry, to name a few. In this context, we propose a complete review on integrated photonic sensors, with specific attention to materials, technologies, architectures and optical sensing principles. To this aim, sensing principles commonly used in optical detection are presented, focusing on sensor performance features such as sensitivity, selectivity and rangeability. Since photonic sensors provide substantial benefits regarding compatibility with CMOS technology and integration on chips characterized by micrometric footprints, design and optimization strategies of photonic devices are widely discussed for sensing applications. In addition, several numerical methods employed in photonic circuits and devices, simulations and design are presented, focusing on their advantages and drawbacks. Finally, recent developments in the field of photonic sensing are reviewed, considering advanced photonic sensor architectures based on linear and non-linear optical effects and to be employed in chemical/biochemical sensing, angular velocity and electric field detection. Full article
(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Italy 2012)
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16 pages, 347 KiB  
Article
Meat and Fish Freshness Inspection System Based on Odor Sensing
by Najam Ul Hasan 1, Naveed Ejaz 2, Waleed Ejaz 1 and Hyung Seok Kim 1,*
1 Department of Information and Communication Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143747, Korea
2 Department of Digital Content, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143747, Korea
Sensors 2012, 12(11), 15542-15557; https://doi.org/10.3390/s121115542 - 9 Nov 2012
Cited by 72 | Viewed by 14572
Abstract
We propose a method for building a simple electronic nose based on commercially available sensors used to sniff in the market and identify spoiled/contaminated meat stocked for sale in butcher shops. Using a metal oxide semiconductor-based electronic nose, we measured the smell signature [...] Read more.
We propose a method for building a simple electronic nose based on commercially available sensors used to sniff in the market and identify spoiled/contaminated meat stocked for sale in butcher shops. Using a metal oxide semiconductor-based electronic nose, we measured the smell signature from two of the most common meat foods (beef and fish) stored at room temperature. Food samples were divided into two groups: fresh beef with decayed fish and fresh fish with decayed beef. The prime objective was to identify the decayed item using the developed electronic nose. Additionally, we tested the electronic nose using three pattern classification algorithms (artificial neural network, support vector machine and k-nearest neighbor), and compared them based on accuracy, sensitivity, and specificity. The results demonstrate that the k-nearest neighbor algorithm has the highest accuracy. Full article
(This article belongs to the Special Issue Odor Detection: Electronic Nose, Olfactometer, and Advanced Instrumentation)
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22 pages, 3004 KiB  
Article
A Current Sensor Based on the Giant Magnetoresistance Effect: Design and Potential Smart Grid Applications
by Yong Ouyang 1, Jinliang He 1,*, Jun Hu 1 and Shan X. Wang 1,2
1 State Key Lab of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084, China
2 Center for Magnetic Nanotechnology, Stanford University, 450 Serra Mall, Stanford, CA 94305, USA
Sensors 2012, 12(11), 15520-15541; https://doi.org/10.3390/s121115520 - 9 Nov 2012
Cited by 146 | Viewed by 15673
Abstract
Advanced sensing and measurement techniques are key technologies to realize a smart grid. The giant magnetoresistance (GMR) effect has revolutionized the fields of data storage and magnetic measurement. In this work, a design of a GMR current sensor based on a commercial analog [...] Read more.
Advanced sensing and measurement techniques are key technologies to realize a smart grid. The giant magnetoresistance (GMR) effect has revolutionized the fields of data storage and magnetic measurement. In this work, a design of a GMR current sensor based on a commercial analog GMR chip for applications in a smart grid is presented and discussed. Static, dynamic and thermal properties of the sensor were characterized. The characterizations showed that in the operation range from 0 to ±5 A, the sensor had a sensitivity of 28 mV·A−1, linearity of 99.97%, maximum deviation of 2.717%, frequency response of −1.5 dB at 10 kHz current measurement, and maximum change of the amplitude response of 0.0335%·°C−1 with thermal compensation. In the distributed real-time measurement and monitoring of a smart grid system, the GMR current sensor shows excellent performance and is cost effective, making it suitable for applications such as steady-state and transient-state monitoring. With the advantages of having a high sensitivity, high linearity, small volume, low cost, and simple structure, the GMR current sensor is promising for the measurement and monitoring of smart grids. Full article
(This article belongs to the Section Physical Sensors)
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20 pages, 890 KiB  
Article
Programmable Ultrasonic Sensing System for Targeted Spraying in Orchards
by Denis Stajnko 1,*, Peter Berk 1, Mario Lešnik 1, Viktor Jejčič 2, Miran Lakota 1, Andrej Štrancar 3, Marko Hočevar 4 and Jurij Rakun 1
1 Faculty of Agriculture and Life Sciences, University of Maribor, 2000 Maribor, Slovenia
2 Agricultural Institute of Slovenia, 1000 Ljubljana, Slovenia
3 Faculty of Computer and Information Science, University of Ljubljana, 1000 Ljubljana, Slovenia
4 Faculty of Mechanical Engineering, University of Ljubljana, 1000 Ljubljana, Slovenia
Sensors 2012, 12(11), 15500-15519; https://doi.org/10.3390/s121115500 - 9 Nov 2012
Cited by 47 | Viewed by 11042
Abstract
This research demonstrates the basic elements of a prototype automated orchard sprayer which delivers pesticide spray selectively with respect to the characteristics of the targets. The density of an apple tree canopy was detected by PROWAVE 400EP250 ultrasound sensors controlled by a Cypress [...] Read more.
This research demonstrates the basic elements of a prototype automated orchard sprayer which delivers pesticide spray selectively with respect to the characteristics of the targets. The density of an apple tree canopy was detected by PROWAVE 400EP250 ultrasound sensors controlled by a Cypress PSOC CY8C29466 microcontroller. The ultrasound signal was processed with an embedded computer built around a LPC1343 microcontroller and fed in real time to electro-magnetic valves which open/close spraying nozzles in relation to the canopy structure. The analysis focuses on the detection of appropriate thresholds on 15 cm ultrasound bands, which correspond to maximal response to tree density, and this was selected for accurate spraying guidance. Evaluation of the system was performed in an apple orchard by detecting deposits of tartrazine dye (TD) on apple leaves. The employment of programmable microcontrollers and electro-magnetic valves decreased the amount of spray delivered by up to 48.15%. In contrast, the reduction of TD was only up to 37.7% at some positions within the tree crown and 65.1% in the gaps between trees. For all these reasons, this concept of precise orchard spraying can contribute to a reduction of costs and environmental pollution, while obtaining similar or even better leaf deposits. Full article
(This article belongs to the Section Physical Sensors)
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33 pages, 4379 KiB  
Review
Porous Bead-Based Diagnostic Platforms: Bridging the Gaps in Healthcare
by Jie Chou 1, Jorge Wong 2, Nicolaos Christodoulides 1,3, Pierre N. Floriano 1,3, Ximena Sanchez 1,3 and John McDevitt 1,3,*
1 Department of Bioengineering, Rice University, 6100 Main St MS-142, Houston, TX 77005, USA
2 Department of Chemistry, University of Texas at Austin, 1 University Station A5300, Austin, TX 78712, USA
3 Department of Chemistry, Rice University, 6100 Main St MS-142, Houston, TX 77005, USA
Sensors 2012, 12(11), 15467-15499; https://doi.org/10.3390/s121115467 - 9 Nov 2012
Cited by 30 | Viewed by 13455
Abstract
Advances in lab-on-a-chip systems have strong potential for multiplexed detection of a wide range of analytes with reduced sample and reagent volume; lower costs and shorter analysis times. The completion of high-fidelity multiplexed and multiclass assays remains a challenge for the medical microdevice [...] Read more.
Advances in lab-on-a-chip systems have strong potential for multiplexed detection of a wide range of analytes with reduced sample and reagent volume; lower costs and shorter analysis times. The completion of high-fidelity multiplexed and multiclass assays remains a challenge for the medical microdevice field; as it struggles to achieve and expand upon at the point-of-care the quality of results that are achieved now routinely in remote laboratory settings. This review article serves to explore for the first time the key intersection of multiplexed bead-based detection systems with integrated microfluidic structures alongside porous capture elements together with biomarker validation studies. These strategically important elements are evaluated here in the context of platform generation as suitable for near-patient testing. Essential issues related to the scalability of these modular sensor ensembles are explored as are attempts to move such multiplexed and multiclass platforms into large-scale clinical trials. Recent efforts in these bead sensors have shown advantages over planar microarrays in terms of their capacity to generate multiplexed test results with shorter analysis times. Through high surface-to-volume ratios and encoding capabilities; porous bead-based ensembles; when combined with microfluidic elements; allow for high-throughput testing for enzymatic assays; general chemistries; protein; antibody and oligonucleotide applications. Full article
(This article belongs to the Special Issue Micro and Nano Technologies for Point-of-Care Diagnosis)
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29 pages, 460 KiB  
Article
An Energy-Efficient Strategy for Accurate Distance Estimation in Wireless Sensor Networks
by Paula Tarrío *, Ana M. Bernardos and José R. Casar
Data Processing and Simulation Group, Universidad Politécnica de Madrid, ETSI. Telecomunicación, Avda. Complutense 30, 28040, Madrid, Spain
Sensors 2012, 12(11), 15438-15466; https://doi.org/10.3390/s121115438 - 9 Nov 2012
Cited by 19 | Viewed by 6138
Abstract
In line with recent research efforts made to conceive energy saving protocols and algorithms and power sensitive network architectures, in this paper we propose a transmission strategy to minimize the energy consumption in a sensor network when using a localization technique based on [...] Read more.
In line with recent research efforts made to conceive energy saving protocols and algorithms and power sensitive network architectures, in this paper we propose a transmission strategy to minimize the energy consumption in a sensor network when using a localization technique based on the measurement of the strength (RSS) or the time of arrival (TOA) of the received signal. In particular, we find the transmission power and the packet transmission rate that jointly minimize the total consumed energy, while ensuring at the same time a desired accuracy in the RSS or TOA measurements. We also propose some corrections to these theoretical results to take into account the effects of shadowing and packet loss in the propagation channel. The proposed strategy is shown to be effective in realistic scenarios providing energy savings with respect to other transmission strategies, and also guaranteeing a given accuracy in the distance estimations, which will serve to guarantee a desired accuracy in the localization result. Full article
(This article belongs to the Section Sensor Networks)
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14 pages, 1050 KiB  
Article
Potentiometric Zinc Ion Sensor Based on Honeycomb-Like NiO Nanostructures
by Mazhar Ali Abbasi 1,*, Zafar Hussain Ibupoto 1, Mushtaque Hussain 1, Yaqoob Khan 2, Azam Khan 1, Omer Nur 1 and Magnus Willander 1
1 Physical Electronic and Nanotechnology Division, Department of Science and Technology, Campus Norrköping, Linköping University, SE-60174 Norrköping, Sweden
2 Nanosciences and Catalysis Division, National Centre for Physics, Quaid-e-Azam University Campus, 45320 Islamabad, Pakistan
Sensors 2012, 12(11), 15424-15437; https://doi.org/10.3390/s121115424 - 9 Nov 2012
Cited by 38 | Viewed by 9711
Abstract
In this study honeycomb-like NiO nanostructures were grown on nickel foam by a simple hydrothermal growth method. The NiO nanostructures were characterized by field emission electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) techniques. The characterized NiO nanostructures [...] Read more.
In this study honeycomb-like NiO nanostructures were grown on nickel foam by a simple hydrothermal growth method. The NiO nanostructures were characterized by field emission electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) techniques. The characterized NiO nanostructures were uniform, dense and polycrystalline in the crystal phase. In addition to this, the NiO nanostructures were used in the development of a zinc ion sensor electrode by functionalization with the highly selective zinc ion ionophore 12-crown-4. The developed zinc ion sensor electrode has shown a good linear potentiometric response for a wide range of zinc ion concentrations, ranging from 0.001 mM to 100 mM, with sensitivity of 36 mV/decade. The detection limit of the present zinc ion sensor was found to be 0.0005 mM and it also displays a fast response time of less than 10 s. The proposed zinc ion sensor electrode has also shown good reproducibility, repeatability, storage stability and selectivity. The zinc ion sensor based on the functionalized NiO nanostructures was also used as indicator electrode in potentiometric titrations and it has demonstrated an acceptable stoichiometric relationship for the determination of zinc ion in unknown samples. The NiO nanostructures-based zinc ion sensor has potential for analysing zinc ion in various industrial, clinical and other real samples. Full article
(This article belongs to the Section Chemical Sensors)
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30 pages, 2187 KiB  
Article
Estimation of PSD Shifts for High-Resolution Metrology of Thickness Micro-Changes with Possible Applications in Vessel Walls and Biological Membrane Characterization
by Antonio Ramos 1,*, Ivonne Bazán 2, Carlos Negreira 3, Javier Brum 3, Tomás Gómez 1, Héctor Calás 1, Abelardo Ruiz 1 and José Manuel de la Rosa 2
1 Laboratorio Señales, Sistemas y Tecnologías Ultrasónicas, Consejo Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
2 ESIME, Instituto Politécnico Nacional (IPN), 07738 México DF, Mexico
3 Departamento de Materiales, Facultad de Ciencias, Universidad de la Republica, 11400 Montevideo, Uruguay
Sensors 2012, 12(11), 15394-15423; https://doi.org/10.3390/s121115394 - 9 Nov 2012
Cited by 16 | Viewed by 8781
Abstract
Achieving accurate measurements of inflammation levels in tissues or thickness changes in biological membranes (e.g., amniotic sac, parietal pleura) and thin biological walls (e.g., blood vessels) from outside the human body, is a promising research line in the medical area. It would provide [...] Read more.
Achieving accurate measurements of inflammation levels in tissues or thickness changes in biological membranes (e.g., amniotic sac, parietal pleura) and thin biological walls (e.g., blood vessels) from outside the human body, is a promising research line in the medical area. It would provide a technical basis to study the options for early diagnosis of some serious diseases such as hypertension, atherosclerosis or tuberculosis. Nevertheless, achieving the aim of non-invasive measurement of those scarcely-accessible parameters on patient internal tissues, currently presents many difficulties. The use of high-frequency ultrasonic transducer systems appears to offer a possible solution. Previous studies using conventional ultrasonic imaging have shown this, but the spatial resolution was not sufficient so as to permit a thickness evaluation with clinical significance, which requires an accuracy of a few microns. In this paper a broadband ultrasonic technique, that was recently developed by the authors to address other non-invasive medical detection problems (by integrating a piezoelectric transducer into a spectral measuring system), is extended to our new objective; the aim is its application to the thickness measurement of sub-millimeter membranes or layers made of materials similar to some biological tissues (phantoms). The modeling and design rules of such a transducer system are described, and various methods of estimating overtones location in the power spectral density (PSD) are quantitatively assessed with transducer signals acquired using piezoelectric systems and also generated from a multi-echo model. Their effects on the potential resolution of the proposed thickness measuring tool, and their capability to provide accuracies around the micron are studied in detail. Comparisons are made with typical tools for extracting spatial parameters in laminar samples from echo-waveforms acquired with ultrasonic transducers. Results of this advanced measurement spectral tool are found to improve the performance of typical cross-correlation methods and provide reliable and high-resolution estimations. Full article
(This article belongs to the Special Issue Transducer Systems)
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18 pages, 1519 KiB  
Article
GrabCut-Based Human Segmentation in Video Sequences
by Antonio Hernández-Vela 1,2,*, Miguel Reyes 1,2, Víctor Ponce 1,2 and Sergio Escalera 1,2
1 Departamento MAIA, Universitat de Barcelona, Gran Via 585, 08007 Barcelona, Spain
2 Centre de Visió per Computador, Campus UAB, Edifici O, 08193 Bellaterra, Barcelona, Spain
Sensors 2012, 12(11), 15376-15393; https://doi.org/10.3390/s121115376 - 9 Nov 2012
Cited by 33 | Viewed by 12146
Abstract
In this paper, we present a fully-automatic Spatio-Temporal GrabCut human segmentation methodology that combines tracking and segmentation. GrabCut initialization is performed by a HOG-based subject detection, face detection, and skin color model. Spatial information is included by Mean Shift clustering whereas temporal coherence [...] Read more.
In this paper, we present a fully-automatic Spatio-Temporal GrabCut human segmentation methodology that combines tracking and segmentation. GrabCut initialization is performed by a HOG-based subject detection, face detection, and skin color model. Spatial information is included by Mean Shift clustering whereas temporal coherence is considered by the historical of Gaussian Mixture Models. Moreover, full face and pose recovery is obtained by combining human segmentation with Active Appearance Models and Conditional Random Fields. Results over public datasets and in a new Human Limb dataset show a robust segmentation and recovery of both face and pose using the presented methodology. Full article
(This article belongs to the Section Physical Sensors)
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20 pages, 1836 KiB  
Article
Development of a Configurable Growth Chamber with a Computer Vision System to Study Circadian Rhythm in Plants
by Pedro J. Navarro 1, Carlos Fernández 1, Julia Weiss 2 and Marcos Egea-Cortines 2,*
1 Universidad Politécnica de Cartagena, Campus Muralla del Mar, s/n. Cartagena 30202, Spain
2 Genética, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena, Cartagena 30202, Spain
Sensors 2012, 12(11), 15356-15375; https://doi.org/10.3390/s121115356 - 9 Nov 2012
Cited by 14 | Viewed by 9293
Abstract
Plant development is the result of an endogenous morphogenetic program that integrates environmental signals. The so-called circadian clock is a set of genes that integrates environmental inputs into an internal pacing system that gates growth and other outputs. Study of circadian growth responses [...] Read more.
Plant development is the result of an endogenous morphogenetic program that integrates environmental signals. The so-called circadian clock is a set of genes that integrates environmental inputs into an internal pacing system that gates growth and other outputs. Study of circadian growth responses requires high sampling rates to detect changes in growth and avoid aliasing. We have developed a flexible configurable growth chamber comprising a computer vision system that allows sampling rates ranging between one image per 30 s to hours/days. The vision system has a controlled illumination system, which allows the user to set up different configurations. The illumination system used emits a combination of wavelengths ensuring the optimal growth of species under analysis. In order to obtain high contrast of captured images, the capture system is composed of two CCD cameras, for day and night periods. Depending on the sample type, a flexible image processing software calculates different parameters based on geometric calculations. As a proof of concept we tested the system in three different plant tissues, growth of petunia- and snapdragon (Antirrhinum majus) flowers and of cladodes from the cactus Opuntia ficus-indica. We found that petunia flowers grow at a steady pace and display a strong growth increase in the early morning, whereas Opuntia cladode growth turned out not to follow a circadian growth pattern under the growth conditions imposed. Furthermore we were able to identify a decoupling of increase in area and length indicating that two independent growth processes are responsible for the final size and shape of the cladode. Full article
(This article belongs to the Special Issue Sensor-Based Technologies and Processes in Agriculture and Forestry)
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18 pages, 1124 KiB  
Article
Exploration and Implementation of a Pre-Impact Fall Recognition Method Based on an Inertial Body Sensor Network
by Guoru Zhao †, Zhanyong Mei †, Ding Liang, Kamen Ivanov, Yanwei Guo, Yongfeng Wang and Lei Wang *
1 Shenzhen Key Laboratory for Low-cost Healthcare, and Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Road, Shenzhen 518055, China
† These authors contributed equally to this work.
Sensors 2012, 12(11), 15338-15355; https://doi.org/10.3390/s121115338 - 8 Nov 2012
Cited by 60 | Viewed by 9698
Abstract
The unintentional injuries due to falls in elderly people give rise to a multitude of health and economic problems due to the growing aging population. The use of early pre-impact fall alarm and self-protective control could greatly reduce fall injuries. This paper aimed [...] Read more.
The unintentional injuries due to falls in elderly people give rise to a multitude of health and economic problems due to the growing aging population. The use of early pre-impact fall alarm and self-protective control could greatly reduce fall injuries. This paper aimed to explore and implement a pre-impact fall recognition/alarm method for free-direction fall activities based on understanding of the pre-impact lead time of falls and the angle of body postural stability using an inertial body sensor network. Eight healthy Asian adult subjects were arranged to perform three kinds of daily living activities and three kinds of fall activities. Nine MTx sensor modules were used to measure the body segmental kinematic characteristics of each subject for pre-impact fall recognition/alarm. Our analysis of the kinematic features of human body segments showed that the chest was the optimal sensor placement for an early pre-impact recognition/alarm (i.e., prediction/alarm of a fall event before it happens) and post-fall detection (i.e., detection of a fall event after it already happened). Furthermore, by comparative analysis of threshold levels for acceleration and angular rate, two acceleration thresholds were determined for early pre-impact alarm (7 m/s/s) and post-fall detection (20 m/s/s) under experimental conditions. The critical angles of postural stability of torso segment in three kinds of fall activities (forward, sideway and backward fall) were determined as 23.9 ± 3.3, 49.9 ± 4.1 and 9.9 ± 2.5 degrees, respectively, and the relative average pre-impact lead times were 329 ± 21, 265 ± 35 and 257 ± 36 ms. The results implied that among the three fall activities the sideway fall was associated with the largest postural stability angle and the forward fall was associated with the longest time to adjust body angle to avoid the fall; the backward fall was the most difficult to avoid among the three kinds of fall events due to the toughest combination of shortest lead time and smallest angle of postural stability which made it difficult for the self-protective control mechanism to adjust the body in time to avoid falling down. Full article
(This article belongs to the Special Issue Body Sensor Networks for Healthcare and Pervasive Applications)
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30 pages, 2074 KiB  
Article
Decentralized Cooperative TOA/AOA Target Tracking for Hierarchical Wireless Sensor Networks
by Ying-Chih Chen and Chih-Yu Wen *
Department of Electrical Engineering, Graduate Institute of Communication Engineering, National Chung Hsing University, Taichung 402, Taiwan
Sensors 2012, 12(11), 15308-15337; https://doi.org/10.3390/s121115308 - 8 Nov 2012
Cited by 13 | Viewed by 7308
Abstract
This paper proposes a distributed method for cooperative target tracking in hierarchical wireless sensor networks. The concept of leader-based information processingis conducted to achieve object positioning, considering a cluster-based network topology. Random timers and local information are applied to adaptively select a sub-cluster [...] Read more.
This paper proposes a distributed method for cooperative target tracking in hierarchical wireless sensor networks. The concept of leader-based information processingis conducted to achieve object positioning, considering a cluster-based network topology. Random timers and local information are applied to adaptively select a sub-cluster for thelocalization task. The proposed energy-efficient tracking algorithm allows each sub-clustermember to locally estimate the target position with a Bayesian filtering framework and a neural networking model, and further performs estimation fusion in the leader node with the covariance intersection algorithm. This paper evaluates the merits and trade-offs of the protocol design towards developing more efficient and practical algorithms for objectposition estimation. Full article
(This article belongs to the Special Issue Ubiquitous Sensing)
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