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Sensors, Volume 12, Issue 3 (March 2012) – 83 articles , Pages 2351-3788

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625 KiB  
Article
A Vocal-Based Analytical Method for Goose Behaviour Recognition
by Kim Arild Steen, Ole Roland Therkildsen, Henrik Karstoft and Ole Green
Sensors 2012, 12(3), 3773-3788; https://doi.org/10.3390/s120303773 - 21 Mar 2012
Cited by 22 | Viewed by 8727
Abstract
Since human-wildlife conflicts are increasing, the development of cost-effective methods for reducing damage or conflict levels is important in wildlife management. A wide range of devices to detect and deter animals causing conflict are used for this purpose, although their effectiveness is often [...] Read more.
Since human-wildlife conflicts are increasing, the development of cost-effective methods for reducing damage or conflict levels is important in wildlife management. A wide range of devices to detect and deter animals causing conflict are used for this purpose, although their effectiveness is often highly variable, due to habituation to disruptive or disturbing stimuli. Automated recognition of behaviours could form a critical component of a system capable of altering the disruptive stimuli to avoid this. In this paper we present a novel method to automatically recognise goose behaviour based on vocalisations from flocks of free-living barnacle geese (Branta leucopsis). The geese were observed and recorded in a natural environment, using a shielded shotgun microphone. The classification used Support Vector Machines (SVMs), which had been trained with labeled data. Greenwood Function Cepstral Coefficients (GFCC) were used as features for the pattern recognition algorithm, as they can be adjusted to the hearing capabilities of different species. Three behaviours are classified based in this approach, and the method achieves a good recognition of foraging behaviour (86–97% sensitivity, 89–98% precision) and a reasonable recognition of flushing (79–86%, 66–80%) and landing behaviour(73–91%, 79–92%). The Support Vector Machine has proven to be a robust classifier for this kind of classification, as generality and non-linearcapabilities are important. We conclude that vocalisations can be used to automatically detect behaviour of conflict wildlife species, and as such, may be used as an integrated part of awildlife management system. Full article
(This article belongs to the Section Physical Sensors)
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665 KiB  
Article
A Pro-Drug Approach for Selective Modulation of AI-2-Mediated Bacterial Cell-to-Cell Communication
by Min Guo, Sonja Gamby, Shizuka Nakayama, Jacqueline Smith and Herman O. Sintim
Sensors 2012, 12(3), 3762-3772; https://doi.org/10.3390/s120303762 - 21 Mar 2012
Cited by 15 | Viewed by 8278
Abstract
The universal quorum sensing autoinducer, AI-2, is utilized by several bacteria. Analogs of AI-2 have the potential to modulate bacterial behavior. Selectively quenching the communication of a few bacteria, in the presence of several others in an ecosystem, using analogs of AI-2 is [...] Read more.
The universal quorum sensing autoinducer, AI-2, is utilized by several bacteria. Analogs of AI-2 have the potential to modulate bacterial behavior. Selectively quenching the communication of a few bacteria, in the presence of several others in an ecosystem, using analogs of AI-2 is non-trivial due to the ubiquity of AI-2 processing receptors in many bacteria that co-exist. Herein, we demonstrate that when an AI-2 analog, isobutyl DPD (which has been previously shown to be a quorum sensing, QS, quencher in both Escherichia coli and Salmonella typhimurium) is modified with ester groups, which get hydrolyzed once inside the bacterial cells, only QS in E. coli, but not in S. typhimurium, is inhibited. The origin of this differential QS inhibition could be due to differences in analog permeation of the bacterial membranes or ester hydrolysis rates. Such differences could be utilized to selectively target QS in specific bacteria amongst a consortium of other species that also use AI-2 signaling. Full article
(This article belongs to the Special Issue Microbial Quorum Sensing: Linking the Outside World to Microbial Behaviour)
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562 KiB  
Article
Robust Facial Expression Recognition via Compressive Sensing
by Shiqing Zhang, Xiaoming Zhao and Bicheng Lei
Sensors 2012, 12(3), 3747-3761; https://doi.org/10.3390/s120303747 - 21 Mar 2012
Cited by 75 | Viewed by 12128
Abstract
Recently, compressive sensing (CS) has attracted increasing attention in the areas of signal processing, computer vision and pattern recognition. In this paper, a new method based on the CS theory is presented for robust facial expression recognition. The CS theory is used to [...] Read more.
Recently, compressive sensing (CS) has attracted increasing attention in the areas of signal processing, computer vision and pattern recognition. In this paper, a new method based on the CS theory is presented for robust facial expression recognition. The CS theory is used to construct a sparse representation classifier (SRC). The effectiveness and robustness of the SRC method is investigated on clean and occluded facial expression images. Three typical facial features, i.e., the raw pixels, Gabor wavelets representation and local binary patterns (LBP), are extracted to evaluate the performance of the SRC method. Compared with the nearest neighbor (NN), linear support vector machines (SVM) and the nearest subspace (NS), experimental results on the popular Cohn-Kanade facial expression database demonstrate that the SRC method obtains better performance and stronger robustness to corruption and occlusion on robust facial expression recognition tasks. Full article
(This article belongs to the Section Physical Sensors)
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497 KiB  
Article
An Acousto-Optical Sensor with High Angular Resolution
by Gennady Kaloshin and Igor Lukin
Sensors 2012, 12(3), 3739-3746; https://doi.org/10.3390/s120303739 - 20 Mar 2012
Cited by 3 | Viewed by 5601
Abstract
The paper introduces a new laser interferometry-based sensor for diagnosis of random media by means of high accuracy angle measurements and describes the results of its development and testing. Theoretical calculations of the dependence of the range of the laser interferometer on laser [...] Read more.
The paper introduces a new laser interferometry-based sensor for diagnosis of random media by means of high accuracy angle measurements and describes the results of its development and testing. Theoretical calculations of the dependence of the range of the laser interferometer on laser beam parameters, device geometry, and atmospheric turbulence characteristics are reported. It is demonstrated that at moderate turbulence intensities corresponding to those observed most frequently in turbulent atmosphere at moderate latitudes and with low interference contrast values, the performance range of the laser interferometer-based device exceeds 5 km. Full article
(This article belongs to the Section Physical Sensors)
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959 KiB  
Article
Design and Testing of a Multi-Sensor Pedestrian Location and Navigation Platform
by Aiden Morrison, Valérie Renaudin, Jared B. Bancroft and Gérard Lachapelle
Sensors 2012, 12(3), 3720-3738; https://doi.org/10.3390/s120303720 - 19 Mar 2012
Cited by 37 | Viewed by 10979
Abstract
avigation and location technologies are continually advancing, allowing ever higher accuracies and operation under ever more challenging conditions. The development of such technologies requires the rapid evaluation of a large number of sensors and related utilization strategies. The integration of Global Navigation Satellite [...] Read more.
avigation and location technologies are continually advancing, allowing ever higher accuracies and operation under ever more challenging conditions. The development of such technologies requires the rapid evaluation of a large number of sensors and related utilization strategies. The integration of Global Navigation Satellite Systems (GNSSs) such as the Global Positioning System (GPS) with accelerometers, gyros, barometers, magnetometers and other sensors is allowing for novel applications, but is hindered by the difficulties to test and compare integrated solutions using multiple sensor sets. In order to achieve compatibility and flexibility in terms of multiple sensors, an advanced adaptable platform is required. This paper describes the design and testing of the NavCube, a multi-sensor navigation, location and timing platform. The system provides a research tool for pedestrian navigation, location and body motion analysis in an unobtrusive form factor that enables in situ data collections with minimal gait and posture impact. Testing and examples of applications of the NavCube are provided. Full article
(This article belongs to the Section Physical Sensors)
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1647 KiB  
Article
Ocean Bottom Seismometer: Design and Test of a Measurement System for Marine Seismology
by Antoni Mànuel, Xavier Roset, Joaquin Del Rio, Daniel Mihai Toma, Normandino Carreras, Shahram Shariat Panahi, A. Garcia-Benadí, Tim Owen and Javier Cadena
Sensors 2012, 12(3), 3693-3719; https://doi.org/10.3390/s120303693 - 19 Mar 2012
Cited by 23 | Viewed by 17662
Abstract
The Ocean Bottom Seismometer (OBS) is a key instrument for the geophysical study of sea sub-bottom layers. At present, more reliable autonomous instruments capable of recording underwater for long periods of time and therefore handling large data storage are needed. This paper presents [...] Read more.
The Ocean Bottom Seismometer (OBS) is a key instrument for the geophysical study of sea sub-bottom layers. At present, more reliable autonomous instruments capable of recording underwater for long periods of time and therefore handling large data storage are needed. This paper presents a new Ocean Bottom Seismometer designed to be used in long duration seismic surveys. Power consumption and noise level of the acquisition system are the key points to optimize the autonomy and the data quality. To achieve our goals, a new low power data logger with high resolution and Signal–to-Noise Ratio (SNR) based on Compact Flash memory card is designed to enable continuous data acquisition. The equipment represents the achievement of joint work from different scientific and technological disciplines as electronics, mechanics, acoustics, communications, information technology, marine geophysics, etc. This easy to handle and sophisticated equipment allows the recording of useful controlled source and passive seismic data, as well as other time varying data, with multiple applications in marine environment research. We have been working on a series of prototypes for ten years to improve many of the aspects that make the equipment easy to handle and useful to work in deep-water areas. Ocean Bottom Seismometers (OBS) have received growing attention from the geoscience community during the last forty years. OBS sensors recording motion of the ocean floor hold key information in order to study offshore seismicity and to explore the Earth’s crust. In a seismic survey, a series of OBSs are placed on the seabed of the area under study, where they record either natural seismic activity or acoustic signals generated by compressed air-guns on the ocean surface. The resulting data sets are subsequently used to model both the earthquake locations and the crustal structure. Full article
(This article belongs to the Special Issue Underwater Sensor Nodes and Underwater Sensor Networks)
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1356 KiB  
Article
Vapochromic Behaviour of M[Au(CN)2]2-Based Coordination Polymers (M = Co, Ni)
by Julie Lefebvre, Jasmine L. Korčok, Michael J. Katz and Daniel B. Leznoff
Sensors 2012, 12(3), 3669-3692; https://doi.org/10.3390/s120303669 - 16 Mar 2012
Cited by 30 | Viewed by 10579
Abstract
A series of M[Au(CN)2]2(analyte)x coordination polymers (M = Co, Ni; analyte = dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), pyridine; x = 2 or 4) was prepared and characterized. Addition of analyte vapours to solid M(μ-OH2)[Au(CN)2]2 [...] Read more.
A series of M[Au(CN)2]2(analyte)x coordination polymers (M = Co, Ni; analyte = dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), pyridine; x = 2 or 4) was prepared and characterized. Addition of analyte vapours to solid M(μ-OH2)[Au(CN)2]2 yielded visible vapochromic responses for M = Co but not M = Ni; the IR νCN spectral region changed in every case. A single crystal structure of Zn[Au(CN)2]2(DMSO)2 revealed a corrugated 2-D layer structure with cis-DMSO units. Reacting a Ni(II) salt and K[Au(CN)2] in DMSO yielded the isostructural Ni[Au(CN)2]2(DMSO)2 product. Co[Au(CN)2]2(DMSO)2 and M[Au(CN)2]2(DMF)2 (M = Co, Ni) complexes have flat 2-D square-grid layer structures with trans-bound DMSO or DMF units; they are formed via vapour absorption by solid M(μ-OH2)[Au(CN)2]2 and from DMSO or DMF solution synthesis. Co[Au(CN)2]2(pyridine)4 is generated via vapour absorption by Co(μ-OH2)[Au(CN)2]2; the analogous Ni complex is synthesized by immersion of Ni(μ-OH2)[Au(CN)2]2 in 4% aqueous pyridine. Similar immersion of Co(μ-OH2)[Au(CN)2]2 yielded Co[Au(CN)2]2(pyridine)2, which has a flat 2-D square-grid structure with trans-pyridine units. Absorption of pyridine vapour by solid Ni(μ-OH2)[Au(CN)2]2 was incomplete, generating a mixture of pyridine-bound complexes. Analyte-free Co[Au(CN)2]2 was prepared by dehydration of Co(μ-OH2)[Au(CN)2]2 at 145 °C; it has a 3-D diamondoid-type structure and absorbs DMSO, DMF and pyridine to give the same materials as by vapour absorption from the hydrate. Full article
(This article belongs to the Special Issue Molecular Devices and Machines: Cooperativity and Multifunctionality)
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635 KiB  
Article
Durability Tests of a Fiber Optic Corrosion Sensor
by Kai Tai Wan and Christopher K.Y. Leung
Sensors 2012, 12(3), 3656-3668; https://doi.org/10.3390/s120303656 - 16 Mar 2012
Cited by 20 | Viewed by 8349
Abstract
Steel corrosion is a major cause of degradation in reinforced concrete structures, and there is a need to develop cost-effective methods to detect the initiation of corrosion in such structures. This paper presents a low cost, easy to use fiber optic corrosion sensor [...] Read more.
Steel corrosion is a major cause of degradation in reinforced concrete structures, and there is a need to develop cost-effective methods to detect the initiation of corrosion in such structures. This paper presents a low cost, easy to use fiber optic corrosion sensor for practical application. Thin iron film is deposited on the end surface of a cleaved optical fiber by sputtering. When light is sent into the fiber, most of it is reflected by the coating. If the surrounding environment is corrosive, the film is corroded and the intensity of the reflected signal drops significantly. In previous work, the sensing principle was verified by various experiments in laboratory and a packaging method was introduced. In this paper, the method of multiplexing several sensors by optical time domain reflectometer (OTDR) and optical splitter is introduced, together with the interpretation of OTDR results. The practical applicability of the proposed sensors is demonstrated in a three-year field trial with the sensors installed in an aggressive marine environment. The durability of the sensor against chemical degradation and physical degradation is also verified by accelerated life test and freeze-thaw cycling test, respectively. Full article
(This article belongs to the Special Issue Optical Fiber Sensors 2012)
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1632 KiB  
Article
Comparison of the Characteristics of Small Commercial NDIR CO2 Sensor Models and Development of a Portable CO2 Measurement Device
by Tomomi Yasuda, Seiichiro Yonemura and Akira Tani
Sensors 2012, 12(3), 3641-3655; https://doi.org/10.3390/s120303641 - 16 Mar 2012
Cited by 128 | Viewed by 17569
Abstract
Many sensors have to be used simultaneously for multipoint carbon dioxide (CO2) observation. All the sensors should be calibrated in advance, but this is a time-consuming process. To seek a simplified calibration method, we used four commercial CO2 sensor models [...] Read more.
Many sensors have to be used simultaneously for multipoint carbon dioxide (CO2) observation. All the sensors should be calibrated in advance, but this is a time-consuming process. To seek a simplified calibration method, we used four commercial CO2 sensor models and characterized their output tendencies against ambient temperature and length of use, in addition to offset characteristics. We used four samples of standard gas with different CO2 concentrations (0, 407, 1,110, and 1,810 ppm). The outputs of K30 and AN100 models showed linear relationships with temperature and length of use. Calibration coefficients for sensor models were determined using the data from three individual sensors of the same model to minimize the relative RMS error. When the correction was applied to the sensors, the accuracy of measurements improved significantly in the case of the K30 and AN100 units. In particular, in the case of K30 the relative RMS error decreased from 24% to 4%. Hence, we have chosen K30 for developing a portable CO2 measurement device (10 × 10 × 15 cm, 900 g). Data of CO2 concentration, measurement time and location, temperature, humidity, and atmospheric pressure can be recorded onto a Secure Digital (SD) memory card. The CO2 concentration in a high-school lecture room was monitored with this device. The CO2 data, when corrected for simultaneously measured temperature, water vapor partial pressure, and atmospheric pressure, showed a good agreement with the data measured by a highly accurate CO2 analyzer, LI-6262. This indicates that acceptable accuracy can be realized using the calibration method developed in this study. Full article
(This article belongs to the Section Chemical Sensors)
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2277 KiB  
Article
Scattering Removal for Finger-Vein Image Restoration
by Jinfeng Yang, Ben Zhang and Yihua Shi
Sensors 2012, 12(3), 3627-3640; https://doi.org/10.3390/s120303627 - 15 Mar 2012
Cited by 54 | Viewed by 10190
Abstract
Finger-vein recognition has received increased attention recently. However, the finger-vein images are always captured in poor quality. This certainly makes finger-vein feature representation unreliable, and further impairs the accuracy of finger-vein recognition. In this paper, we first give an analysis of the intrinsic [...] Read more.
Finger-vein recognition has received increased attention recently. However, the finger-vein images are always captured in poor quality. This certainly makes finger-vein feature representation unreliable, and further impairs the accuracy of finger-vein recognition. In this paper, we first give an analysis of the intrinsic factors causing finger-vein image degradation, and then propose a simple but effective image restoration method based on scattering removal. To give a proper description of finger-vein image degradation, a biological optical model (BOM) specific to finger-vein imaging is proposed according to the principle of light propagation in biological tissues. Based on BOM, the light scattering component is sensibly estimated and properly removed for finger-vein image restoration. Finally, experimental results demonstrate that the proposed method is powerful in enhancing the finger-vein image contrast and in improving the finger-vein image matching accuracy. Full article
(This article belongs to the Special Issue Hand-Based Biometrics Sensors and Systems)
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653 KiB  
Article
On the Statistical Errors of RADAR Location Sensor Networks with Built-In Wi-Fi Gaussian Linear Fingerprints
by Mu Zhou, Yu Bin Xu, Lin Ma and Shuo Tian
Sensors 2012, 12(3), 3605-3626; https://doi.org/10.3390/s120303605 - 15 Mar 2012
Cited by 20 | Viewed by 7255
Abstract
The expected errors of RADAR sensor networks with linear probabilistic location fingerprints inside buildings with varying Wi-Fi Gaussian strength are discussed. As far as we know, the statistical errors of equal and unequal-weighted RADAR networks have been suggested as a better way to [...] Read more.
The expected errors of RADAR sensor networks with linear probabilistic location fingerprints inside buildings with varying Wi-Fi Gaussian strength are discussed. As far as we know, the statistical errors of equal and unequal-weighted RADAR networks have been suggested as a better way to evaluate the behavior of different system parameters and the deployment of reference points (RPs). However, up to now, there is still not enough related work on the relations between the statistical errors, system parameters, number and interval of the RPs, let alone calculating the correlated analytical expressions of concern. Therefore, in response to this compelling problem, under a simple linear distribution model, much attention will be paid to the mathematical relations of the linear expected errors, number of neighbors, number and interval of RPs, parameters in logarithmic attenuation model and variations of radio signal strength (RSS) at the test point (TP) with the purpose of constructing more practical and reliable RADAR location sensor networks (RLSNs) and also guaranteeing the accuracy requirements for the location based services in future ubiquitous context-awareness environments. Moreover, the numerical results and some real experimental evaluations of the error theories addressed in this paper will also be presented for our future extended analysis. Full article
(This article belongs to the Section Sensor Networks)
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855 KiB  
Article
A Voltage Mode Memristor Bridge Synaptic Circuit with Memristor Emulators
by Maheshwar Pd. Sah, Changju Yang, Hyongsuk Kim and Leon Chua
Sensors 2012, 12(3), 3587-3604; https://doi.org/10.3390/s120303587 - 14 Mar 2012
Cited by 71 | Viewed by 15388
Abstract
A memristor bridge neural circuit which is able to perform signed synaptic weighting was proposed in our previous study, where the synaptic operation was verified via software simulation of the mathematical model of the HP memristor. This study is an extension of the [...] Read more.
A memristor bridge neural circuit which is able to perform signed synaptic weighting was proposed in our previous study, where the synaptic operation was verified via software simulation of the mathematical model of the HP memristor. This study is an extension of the previous work advancing toward the circuit implementation where the architecture of the memristor bridge synapse is built with memristor emulator circuits. In addition, a simple neural network which performs both synaptic weighting and summation is built by combining memristor emulators-based synapses and differential amplifier circuits. The feasibility of the memristor bridge neural circuit is verified via SPICE simulations. Full article
(This article belongs to the Section Physical Sensors)
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383 KiB  
Article
Electrical Characterization of Gold-DNA-Gold Structures in Presence of an External Magnetic Field by Means of I-V Curve Analysis
by Nadia Mahmoudi Khatir, Seyedeh Maryam Banihashemian, Vengadesh Periasamy, Richard Ritikos, Wan Haliza Abd Majid and Saadah Abdul Rahman
Sensors 2012, 12(3), 3578-3586; https://doi.org/10.3390/s120303578 - 14 Mar 2012
Cited by 18 | Viewed by 8157
Abstract
This work presents an experimental study of gold-DNA-gold structures in the presence and absence of external magnetic fields with strengths less than 1,200.00 mT. The DNA strands, extracted by standard method were used to fabricate a Metal-DNA-Metal (MDM) structure. Its electric behavior when [...] Read more.
This work presents an experimental study of gold-DNA-gold structures in the presence and absence of external magnetic fields with strengths less than 1,200.00 mT. The DNA strands, extracted by standard method were used to fabricate a Metal-DNA-Metal (MDM) structure. Its electric behavior when subjected to a magnetic field was studied through its current-voltage (I-V) curve. Acquisition of the I-V curve demonstrated that DNA as a semiconductor exhibits diode behavior in the MDM structure. The current versus magnetic field strength followed a decreasing trend because of a diminished mobility in the presence of a low magnetic field. This made clear that an externally imposed magnetic field would boost resistance of the MDM structure up to 1,000.00 mT and for higher magnetic field strengths we can observe an increase in potential barrier in MDM junction. The magnetic sensitivity indicates the promise of using MDM structures as potential magnetic sensors. Full article
(This article belongs to the Special Issue Nano-Biosensors)
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1901 KiB  
Article
Electrochemical Oxidation of Cysteine at a Film Gold Modified Carbon Fiber Microelectrode Its Application in a Flow—Through Voltammetric Sensor
by Lai-Hao Wang and Wen-Shiuan Huang
Sensors 2012, 12(3), 3562-3577; https://doi.org/10.3390/s120303562 - 14 Mar 2012
Cited by 31 | Viewed by 8444
Abstract
A flow-electrolytical cell containing a strand of micro Au modified carbon fiber electrodes (CFE) has been designedand characterized for use in a voltammatric detector for detecting cysteine using high-performance liquid chromatography. Cysteine is more efficiently electrochemical oxidized on a Au /CFE than a [...] Read more.
A flow-electrolytical cell containing a strand of micro Au modified carbon fiber electrodes (CFE) has been designedand characterized for use in a voltammatric detector for detecting cysteine using high-performance liquid chromatography. Cysteine is more efficiently electrochemical oxidized on a Au /CFE than a bare gold and carbon fiber electrode. The possible reaction mechanism of the oxidation process is described from the relations to scan rate, peak potentials and currents. For the pulse mode, and measurements with suitable experimental parameters, a linear concentration from 0.5 to 5.0 mg·L−1 was found. The limit of quantification for cysteine was below 60 ng·mL−1. Full article
(This article belongs to the Section Chemical Sensors)
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2091 KiB  
Article
Evaluation of a Change Detection Methodology by Means of Binary Thresholding Algorithms and Informational Fusion Processes
by Iñigo Molina, Estibaliz Martinez, Agueda Arquero, Gonzalo Pajares and Javier Sanchez
Sensors 2012, 12(3), 3528-3561; https://doi.org/10.3390/s120303528 - 13 Mar 2012
Cited by 19 | Viewed by 8810
Abstract
Landcover is subject to continuous changes on a wide variety of temporal and spatial scales. Those changes produce significant effects in human and natural activities. Maintaining an updated spatial database with the occurred changes allows a better monitoring of the Earth’s resources and [...] Read more.
Landcover is subject to continuous changes on a wide variety of temporal and spatial scales. Those changes produce significant effects in human and natural activities. Maintaining an updated spatial database with the occurred changes allows a better monitoring of the Earth’s resources and management of the environment. Change detection (CD) techniques using images from different sensors, such as satellite imagery, aerial photographs, etc., have proven to be suitable and secure data sources from which updated information can be extracted efficiently, so that changes can also be inventoried and monitored. In this paper, a multisource CD methodology for multiresolution datasets is applied. First, different change indices are processed, then different thresholding algorithms for change/no_change are applied to these indices in order to better estimate the statistical parameters of these categories, finally the indices are integrated into a change detection multisource fusion process, which allows generating a single CD result from several combination of indices. This methodology has been applied to datasets with different spectral and spatial resolution properties. Then, the obtained results are evaluated by means of a quality control analysis, as well as with complementary graphical representations. The suggested methodology has also been proved efficiently for identifying the change detection index with the higher contribution. Full article
(This article belongs to the Section Remote Sensors)
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722 KiB  
Article
Inertial Sensing to Determine Movement Disorder Motion Present before and after Treatment
by Wesley J. E. Teskey, Mohamed Elhabiby and Naser El-Sheimy
Sensors 2012, 12(3), 3512-3527; https://doi.org/10.3390/s120303512 - 12 Mar 2012
Cited by 23 | Viewed by 7134
Abstract
There has been a lot of interest in recent years in using inertial sensors (accelerometers and gyroscopes) to monitor movement disorder motion and monitor the efficacy of treatment options. Two of the most prominent movement disorders, which are under evaluation in this research [...] Read more.
There has been a lot of interest in recent years in using inertial sensors (accelerometers and gyroscopes) to monitor movement disorder motion and monitor the efficacy of treatment options. Two of the most prominent movement disorders, which are under evaluation in this research paper, are essential tremor (ET) and Parkinson’s disease (PD). These movement disorders are first evaluated to show that ET and PD motion often depict more (tremor) motion content in the 3–12 Hz frequency band of interest than control data and that such tremor motion can be characterized using inertial sensors. As well, coherence analysis is used to compare between pairs of many of the six degrees-of-freedom of motions under evaluation, to determine the similarity in tremor motion for the various degrees-of-freedom at different frequency bands of interest. It was quite surprising that this coherence analysis depicts that there is a statistically significant relationship using coherence analysis when differentiating between control and effectively medicated PD motion. The statistical analysis uncovers the novel finding that PD medication induced dyskinesia is depicted within coherence data from inertial signals. Dyskinesia is involuntary motion or the absence of intended motion, and it is a common side effect among medicated PD patients. The results show that inertial sensors can be used to differentiate between effectively medicated PD motion and control motion; such a differentiation can often be difficult to perform with the human eye because effectively medicated PD patients tend to not produce much tremor. As well, the finding that PD motion, when well medicated, does still differ significantly from control motion allows for researchers to quantify potential deficiencies in the use of medication. By using inertial sensors to spot such deficiencies, as outlined in this research paper, it is hoped that medications with even a larger degree of efficacy can be created in the future. Full article
(This article belongs to the Section Physical Sensors)
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748 KiB  
Article
A Non-Destructive Distinctive Method for Discrimination of Automobile Lubricant Variety by Visible and Short-Wave Infrared Spectroscopy
by Lulu Jiang, Fei Liu and Yong He
Sensors 2012, 12(3), 3498-3511; https://doi.org/10.3390/s120303498 - 12 Mar 2012
Cited by 15 | Viewed by 6871
Abstract
A novel method which is a combination of wavelet packet transform (WPT), uninformative variable elimination by partial least squares (UVE-PLS) and simulated annealing (SA) to extract best variance information among different varieties of lubricants is presented. A total of 180 samples (60 for [...] Read more.
A novel method which is a combination of wavelet packet transform (WPT), uninformative variable elimination by partial least squares (UVE-PLS) and simulated annealing (SA) to extract best variance information among different varieties of lubricants is presented. A total of 180 samples (60 for each variety) were characterized on the basis of visible and short-wave infrared spectroscopy (VIS-SWNIR), and 90 samples (30 for each variety) were randomly selected for the calibration set, whereas, the remaining 90 samples (30 for each variety) were used for the validation set. The spectral data was split into different frequency bands by WPT, and different frequency bands were obtained. SA was employed to look for the best variance band (BVB) among different varieties of lubricants. In order to improve prediction precision further, BVB was processed by UVE-PLS and the optimal cutoff threshold of UVE was found by SA. Finally, five variables were mined, and were set as inputs for a least square-support vector machine (LS-SVM) to build the recognition model. An optimal model with a correlation coefficient (R) of 0.9850 and root mean square error of prediction (RMSEP) of 0.0827 was obtained. The overall results indicated that the method of combining WPT, UVE-PLS and SA was a powerful way to select diagnostic information for discrimination among different varieties of lubricating oil, furthermore, a more parsimonious and efficient LS-SVM model could be obtained. Full article
(This article belongs to the Section Physical Sensors)
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473 KiB  
Article
N-Acyl Homoserine Lactones in Diverse Pectobacterium and Dickeya Plant Pathogens: Diversity, Abundance, and Involvement in Virulence
by Alexandre Crépin, Amélie Beury-Cirou, Corinne Barbey, Christine Farmer, Valérie Hélias, Jean-François Burini, Denis Faure and Xavier Latour
Sensors 2012, 12(3), 3484-3497; https://doi.org/10.3390/s120303484 - 12 Mar 2012
Cited by 40 | Viewed by 14961
Abstract
Soft-rot bacteria Pectobacterium and Dickeya use N-acyl homoserine lactones (NAHSLs) as diffusible signals for coordinating quorum sensing communication. The production of NAHSLs was investigated in a set of reference strains and recently-collected isolates, which belong to six species and share the ability [...] Read more.
Soft-rot bacteria Pectobacterium and Dickeya use N-acyl homoserine lactones (NAHSLs) as diffusible signals for coordinating quorum sensing communication. The production of NAHSLs was investigated in a set of reference strains and recently-collected isolates, which belong to six species and share the ability to infect the potato host plant. All the pathogens produced different NAHSLs, among which the 3-oxo-hexanoyl- and the 3-oxo-octanoyl-L-homoserine lactones represent at least 90% of total produced NAHSL-amounts. The level of NAHSLs varied from 0.6 to 2 pg/cfu. The involvement of NAHSLs in tuber maceration was investigated by electroporating a quorum quenching vector in each of the bacterial pathogen strains. All the NAHSL-lactonase expressing strains produced a lower amount of NAHSLs as compared to those harboring the empty vector. Moreover, all except Dickeya dadantii 3937 induced a lower level of symptoms in potato tuber assay. Noticeably, aggressiveness appeared to be independent of both nature and amount of produced signals. This work highlights that quorum sensing similarly contributed to virulence in most of the tested Pectobacterium and Dickeya, even the strains had been isolated recently or during the past decades. Thus, these key regulatory-molecules appear as credible targets for developing anti-virulence strategies against these plant pathogens. Full article
(This article belongs to the Special Issue Microbial Quorum Sensing: Linking the Outside World to Microbial Behaviour)
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Graphical abstract

538 KiB  
Article
N-Acyl Homoserine Lactone Production by Klebsiella pneumoniae Isolated from Human Tongue Surface
by Wai-Fong Yin, Kathiravan Purmal, Shenyang Chin, Xin-Yue Chan, Chong-Lek Koh, Choon-Kook Sam and Kok-Gan Chan
Sensors 2012, 12(3), 3472-3483; https://doi.org/10.3390/s120303472 - 12 Mar 2012
Cited by 47 | Viewed by 11809
Abstract
Bacteria communicate by producing quorum sensing molecules called autoinducers, which include autoinducer-1, an N-hexanoyl homoserine lactone (AHL), and autoinducer-2. Bacteria present in the human oral cavity have been shown to produce autoinducer-2, but not AHL. Here, we report the isolation of two [...] Read more.
Bacteria communicate by producing quorum sensing molecules called autoinducers, which include autoinducer-1, an N-hexanoyl homoserine lactone (AHL), and autoinducer-2. Bacteria present in the human oral cavity have been shown to produce autoinducer-2, but not AHL. Here, we report the isolation of two AHL-producing Klebsiella pneumoniae strains from the posterior dorsal surface of the tongue of a healthy individual. Spent culture supernatant extracts from K. pneumoniae activated the biosensors Agrobacterium tumefaciens NTL4(pZLR4) and Escherichia coli [pSB401], suggesting the presence of both long and short chain AHLs. High resolution mass spectrometry analyses of these extracts confirmed that both K. pneumoniae isolates produced N-octanoylhomoserine lactone and N-3-dodecanoyl-L-homoserine lactone. To the best of our knowledge, this is the first report of the isolation of K. pneumoniae from the posterior dorsal surface of the human tongue and the production of these AHLs by this bacterium. Full article
(This article belongs to the Section Biosensors)
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588 KiB  
Review
New Trends in Impedimetric Biosensors for the Detection of Foodborne Pathogenic Bacteria
by Yixian Wang, Zunzhong Ye and Yibin Ying
Sensors 2012, 12(3), 3449-3471; https://doi.org/10.3390/s120303449 - 12 Mar 2012
Cited by 228 | Viewed by 17610
Abstract
The development of a rapid, sensitive, specific method for the foodborne pathogenic bacteria detection is of great importance to ensure food safety and security. In recent years impedimetric biosensors which integrate biological recognition technology and impedance have gained widespread application in the field [...] Read more.
The development of a rapid, sensitive, specific method for the foodborne pathogenic bacteria detection is of great importance to ensure food safety and security. In recent years impedimetric biosensors which integrate biological recognition technology and impedance have gained widespread application in the field of bacteria detection. This paper presents an overview on the progress and application of impedimetric biosensors for detection of foodborne pathogenic bacteria, particularly the new trends in the past few years, including the new specific bio-recognition elements such as bacteriophage and lectin, the use of nanomaterials and microfluidics techniques. The applications of these new materials or techniques have provided unprecedented opportunities for the development of high-performance impedance bacteria biosensors. The significant developments of impedimetric biosensors for bacteria detection in the last five years have been reviewed according to the classification of with or without specific bio-recognition element. In addition, some microfluidics systems, which were used in the construction of impedimetric biosensors to improve analytical performance, are introduced in this review. Full article
(This article belongs to the Special Issue Sensing at the Nano-Scale: Chemical and Bio-Sensing)
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324 KiB  
Article
Amplified OTDR Systems for Multipoint Corrosion Monitoring
by Jehan F. Nascimento, Marcionilo J. Silva, Isnaldo J. S. Coêlho, Eliel Cipriano and Joaquim F. Martins-Filho
Sensors 2012, 12(3), 3438-3448; https://doi.org/10.3390/s120303438 - 12 Mar 2012
Cited by 13 | Viewed by 6993
Abstract
We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR) technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the [...] Read more.
We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR) technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment. The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration. The other amplified monitoring system uses an EDFA in booster configuration and we perform corrosion measurements and evaluations of system sensitivity to amplifier gain variations. Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations. Full article
(This article belongs to the Special Issue Optical Fiber Sensors 2012)
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878 KiB  
Article
Improving Fingerprint Verification Using Minutiae Triplets
by Miguel Angel Medina-Pérez, Milton García-Borroto, Andres Eduardo Gutierrez-Rodríguez and Leopoldo Altamirano-Robles
Sensors 2012, 12(3), 3418-3437; https://doi.org/10.3390/s120303418 - 8 Mar 2012
Cited by 59 | Viewed by 12146
Abstract
Improving fingerprint matching algorithms is an active and important research area in fingerprint recognition. Algorithms based on minutia triplets, an important matcher family, present some drawbacks that impact their accuracy, such as dependency to the order of minutiae in the feature, insensitivity to [...] Read more.
Improving fingerprint matching algorithms is an active and important research area in fingerprint recognition. Algorithms based on minutia triplets, an important matcher family, present some drawbacks that impact their accuracy, such as dependency to the order of minutiae in the feature, insensitivity to the reflection of minutiae triplets, and insensitivity to the directions of the minutiae relative to the sides of the triangle. To alleviate these drawbacks, we introduce in this paper a novel fingerprint matching algorithm, named M3gl. This algorithm contains three components: a new feature representation containing clockwise-arranged minutiae without a central minutia, a new similarity measure that shifts the triplets to find the best minutiae correspondence, and a global matching procedure that selects the alignment by maximizing the amount of global matching minutiae. To make M3gl faster, it includes some optimizations to discard non-matching minutia triplets without comparing the whole representation. In comparison with six verification algorithms, M3gl achieves the highest accuracy in the lowest matching time, using FVC2002 and FVC2004 databases. Full article
(This article belongs to the Special Issue Hand-Based Biometrics Sensors and Systems)
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467 KiB  
Article
Simultaneous Source Localization and Polarization Estimation via Non-Orthogonal Joint Diagonalization with Vector-Sensors
by Xiao-Feng Gong, Ke Wang, Qiu-Hua Lin, Zhi-Wen Liu and You-Gen Xu
Sensors 2012, 12(3), 3394-3417; https://doi.org/10.3390/s120303394 - 8 Mar 2012
Cited by 10 | Viewed by 7233
Abstract
Joint estimation of direction-of-arrival (DOA) and polarization with electromagnetic vector-sensors (EMVS) is considered in the framework of complex-valued non-orthogonal joint diagonalization (CNJD). Two new CNJD algorithms are presented, which propose to tackle the high dimensional optimization problem in CNJD via a sequence of [...] Read more.
Joint estimation of direction-of-arrival (DOA) and polarization with electromagnetic vector-sensors (EMVS) is considered in the framework of complex-valued non-orthogonal joint diagonalization (CNJD). Two new CNJD algorithms are presented, which propose to tackle the high dimensional optimization problem in CNJD via a sequence of simple sub-optimization problems, by using LU or LQ decompositions of the target matrices as well as the Jacobi-type scheme. Furthermore, based on the above CNJD algorithms we present a novel strategy to exploit the multi-dimensional structure present in the second-order statistics of EMVS outputs for simultaneous DOA and polarization estimation. Simulations are provided to compare the proposed strategy with existing tensorial or joint diagonalization based methods. Full article
(This article belongs to the Section Physical Sensors)
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5449 KiB  
Article
Cell-Based Sensor System Using L6 Cells for Broad Band Continuous Pollutant Monitoring in Aquatic Environments
by Rebekka Kubisch, Ulrich Bohrn, Maximilian Fleischer and Evamaria Stütz
Sensors 2012, 12(3), 3370-3393; https://doi.org/10.3390/s120303370 - 8 Mar 2012
Cited by 23 | Viewed by 10024
Abstract
Pollution of drinking water sources represents a continuously emerging problem in global environmental protection. Novel techniques for real-time monitoring of water quality, capable of the detection of unanticipated toxic and bioactive substances, are urgently needed. In this study, the applicability of a cell-based [...] Read more.
Pollution of drinking water sources represents a continuously emerging problem in global environmental protection. Novel techniques for real-time monitoring of water quality, capable of the detection of unanticipated toxic and bioactive substances, are urgently needed. In this study, the applicability of a cell-based sensor system using selected eukaryotic cell lines for the detection of aquatic pollutants is shown. Readout parameters of the cells were the acidification (metabolism), oxygen consumption (respiration) and impedance (morphology) of the cells. A variety of potential cytotoxic classes of substances (heavy metals, pharmaceuticals, neurotoxins, waste water) was tested with monolayers of L6 cells (rat myoblasts). The cytotoxicity or cellular effects induced by inorganic ions (Ni2+ and Cu2+) can be detected with the metabolic parameters acidification and respiration down to 0.5 mg/L, whereas the detection limit for other substances like nicotine and acetaminophen are rather high, in the range of 0.1 mg/L and 100 mg/L. In a close to application model a real waste water sample shows detectable signals, indicating the existence of cytotoxic substances. The results support the paradigm change from single substance detection to the monitoring of overall toxicity. Full article
(This article belongs to the Special Issue Live Cell-Based Sensors)
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166 KiB  
Review
Circulating microRNAs as Biomarkers, Therapeutic Targets, and Signaling Molecules
by Seena K. Ajit
Sensors 2012, 12(3), 3359-3369; https://doi.org/10.3390/s120303359 - 8 Mar 2012
Cited by 145 | Viewed by 12655
Abstract
Small noncoding microRNAs (miRNAs) are important regulators of post-transcriptional gene regulation and have altered the prevailing view of a linear relationship between gene and protein expression. Aberrant miRNA expression is an emerging theme for a wide variety of diseases, highlighting the fundamental role [...] Read more.
Small noncoding microRNAs (miRNAs) are important regulators of post-transcriptional gene regulation and have altered the prevailing view of a linear relationship between gene and protein expression. Aberrant miRNA expression is an emerging theme for a wide variety of diseases, highlighting the fundamental role played by miRNAs in both physiological and pathological states. The identification of stable miRNAs in bodily fluids paved the way for their use as novel biomarkers amenable to clinical diagnosis in translational medicine. Identification of miRNAs in exosomes that are functional upon delivery to the recipient cells has highlighted a novel method of intercellular communication. Delivery of miRNAs to recipient cells via blood, with functional gene regulatory consequences, opens up novel avenues for target intervention. Exosomes thus offer a novel strategy for delivering drugs or RNA therapeutic agents. Though much work lies ahead, circulating miRNAs are unequivocally ushering in a new era of novel biomarker discovery, intercellular communication mechanisms, and therapeutic intervention strategies. Full article
(This article belongs to the Special Issue Biomarkers and Nanosensors: New Approaches for Biology and Medicine)
462 KiB  
Article
Novel Principle of Contactless Gauge Block Calibration
by Zdeněk Buchta, Šimon Řeřucha, Břetislav Mikel, Martin Čížek, Josef Lazar and Ondřej Číp
Sensors 2012, 12(3), 3350-3358; https://doi.org/10.3390/s120303350 - 8 Mar 2012
Cited by 22 | Viewed by 8375
Abstract
In this paper, a novel principle of contactless gauge block calibration is presented. The principle of contactless gauge block calibration combines low-coherence interferometry and laser interferometry. An experimental setup combines Dowell interferometer and Michelson interferometer to ensure a gauge block length determination with [...] Read more.
In this paper, a novel principle of contactless gauge block calibration is presented. The principle of contactless gauge block calibration combines low-coherence interferometry and laser interferometry. An experimental setup combines Dowell interferometer and Michelson interferometer to ensure a gauge block length determination with direct traceability to the primary length standard. By monitoring both gauge block sides with a digital camera gauge block 3D surface measurements are possible too. The principle presented is protected by the Czech national patent No. 302948. Full article
(This article belongs to the Section Physical Sensors)
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285 KiB  
Review
Quorum Sensing and Expression of Virulence in Pectobacteria
by Lee Põllumaa, Tiina Alamäe and Andres Mäe
Sensors 2012, 12(3), 3327-3349; https://doi.org/10.3390/s120303327 - 8 Mar 2012
Cited by 74 | Viewed by 11407
Abstract
Quorum sensing (QS) is a population density-dependent regulatory mechanism in which gene expression is coupled to the accumulation of a chemical signaling molecule. QS systems are widespread among the plant soft-rotting bacteria. In Pectobacterium carotovorum, at least two QS systems exist being [...] Read more.
Quorum sensing (QS) is a population density-dependent regulatory mechanism in which gene expression is coupled to the accumulation of a chemical signaling molecule. QS systems are widespread among the plant soft-rotting bacteria. In Pectobacterium carotovorum, at least two QS systems exist being specified by the nature of chemical signals involved. QS in Pectobacterium carotovorum uses N-acylhomoserine lactone (AHL) based, as well as autoinducer-2 (AI-2) dependent signaling systems. This review will address the importance of the QS in production of virulence factors and interaction of QS with other regulatory systems in Pectobacterium carotovorum. Full article
(This article belongs to the Special Issue Microbial Quorum Sensing: Linking the Outside World to Microbial Behaviour)
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1015 KiB  
Article
Dynamic Strain Measured by Mach-Zehnder Interferometric Optical Fiber Sensors
by Shiuh-Chuan Her and Chih-Min Yang
Sensors 2012, 12(3), 3314-3326; https://doi.org/10.3390/s120303314 - 8 Mar 2012
Cited by 27 | Viewed by 9584
Abstract
Optical fibers possess many advantages such as small size, light weight and immunity to electro-magnetic interference that meet the sensing requirements to a large extent. In this investigation, a Mach-Zehnder interferometric optical fiber sensor is used to measure the dynamic strain of a [...] Read more.
Optical fibers possess many advantages such as small size, light weight and immunity to electro-magnetic interference that meet the sensing requirements to a large extent. In this investigation, a Mach-Zehnder interferometric optical fiber sensor is used to measure the dynamic strain of a vibrating cantilever beam. A 3 × 3 coupler is employed to demodulate the phase shift of the Mach-Zehnder interferometer. The dynamic strain of a cantilever beam subjected to base excitation is determined by the optical fiber sensor. The experimental results are validated with the strain gauge. Full article
(This article belongs to the Special Issue Optical Fiber Sensors 2012)
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384 KiB  
Article
TiO2 Nanotube Array Sensor for Detecting the SF6 Decomposition Product SO2
by Xiaoxing Zhang, Jinbin Zhang, Yichao Jia, Peng Xiao and Ju Tang
Sensors 2012, 12(3), 3302-3313; https://doi.org/10.3390/s120303302 - 7 Mar 2012
Cited by 117 | Viewed by 9665
Abstract
The detection of partial discharge through analysis of SF6 gas components in gas-insulated switchgear, is significant for the diagnosis and assessment of the operating state of power equipment. The present study proposes the use of a TiO2 nanotube array sensor for [...] Read more.
The detection of partial discharge through analysis of SF6 gas components in gas-insulated switchgear, is significant for the diagnosis and assessment of the operating state of power equipment. The present study proposes the use of a TiO2 nanotube array sensor for detecting the SF6 decomposition product SO2, and the application of the anodic oxidation method for the directional growth of highly ordered TiO2 nanotube arrays. The sensor response of 10–50 ppm SO2 gas is tested, and the sensitive response mechanism is discussed. The test results show that the TiO2 nanotube sensor array has good response to SO2 gas, and by ultraviolet radiation, the sensor can remove attached components very efficiently, shorten recovery time, reduce chemical poisoning, and prolong the life of the components. Full article
(This article belongs to the Special Issue Sensing at the Nano-Scale: Chemical and Bio-Sensing)
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473 KiB  
Article
Consolidation of a WSN and Minimax Method to Rapidly Neutralise Intruders in Strategic Installations
by Jesus Conesa-Muñoz and Angela Ribeiro
Sensors 2012, 12(3), 3281-3301; https://doi.org/10.3390/s120303281 - 7 Mar 2012
Cited by 3 | Viewed by 7196
Abstract
Due to the sensitive international situation caused by still-recent terrorist attacks, there is a common need to protect the safety of large spaces such as government buildings, airports and power stations. To address this problem, developments in several research fields, such as video [...] Read more.
Due to the sensitive international situation caused by still-recent terrorist attacks, there is a common need to protect the safety of large spaces such as government buildings, airports and power stations. To address this problem, developments in several research fields, such as video and cognitive audio, decision support systems, human interface, computer architecture, communications networks and communications security, should be integrated with the goal of achieving advanced security systems capable of checking all of the specified requirements and spanning the gap that presently exists in the current market. This paper describes the implementation of a decision system for crisis management in infrastructural building security. Specifically, it describes the implementation of a decision system in the management of building intrusions. The positions of the unidentified persons are reported with the help of a Wireless Sensor Network (WSN). The goal is to achieve an intelligent system capable of making the best decision in real time in order to quickly neutralise one or more intruders who threaten strategic installations. It is assumed that the intruders’ behaviour is inferred through sequences of sensors’ activations and their fusion. This article presents a general approach to selecting the optimum operation from the available neutralisation strategies based on a Minimax algorithm. The distances among different scenario elements will be used to measure the risk of the scene, so a path planning technique will be integrated in order to attain a good performance. Different actions to be executed over the elements of the scene such as moving a guard, blocking a door or turning on an alarm will be used to neutralise the crisis. This set of actions executed to stop the crisis is known as the neutralisation strategy. Finally, the system has been tested in simulations of real situations, and the results have been evaluated according to the final state of the intruders. In 86.5% of the cases, the system achieved the capture of the intruders, and in 59.25% of the cases, they were intercepted before they reached their objective. Full article
(This article belongs to the Special Issue Collaborative Sensors)
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