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Sensors, Volume 13, Issue 2 (February 2013), Pages 1385-2699

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Open AccessArticle A Unified Framework for Activity Recognition-Based Behavior Analysis and Action Prediction in Smart Homes
Sensors 2013, 13(2), 2682-2699; https://doi.org/10.3390/s130202682
Received: 16 December 2012 / Revised: 12 February 2013 / Accepted: 15 February 2013 / Published: 22 February 2013
Cited by 24 | PDF Full-text (615 KB) | HTML Full-text | XML Full-text
Abstract
In recent years, activity recognition in smart homes is an active research area due to its applicability in many applications, such as assistive living and healthcare. Besides activity recognition, the information collected from smart homes has great potential for other application domains like
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In recent years, activity recognition in smart homes is an active research area due to its applicability in many applications, such as assistive living and healthcare. Besides activity recognition, the information collected from smart homes has great potential for other application domains like lifestyle analysis, security and surveillance, and interaction monitoring. Therefore, discovery of users common behaviors and prediction of future actions from past behaviors become an important step towards allowing an environment to provide personalized service. In this paper, we develop a unified framework for activity recognition-based behavior analysis and action prediction. For this purpose, first we propose kernel fusion method for accurate activity recognition and then identify the significant sequential behaviors of inhabitants from recognized activities of their daily routines. Moreover, behaviors patterns are further utilized to predict the future actions from past activities. To evaluate the proposed framework, we performed experiments on two real datasets. The results show a remarkable improvement of 13.82% in the accuracy on average of recognized activities along with the extraction of significant behavioral patterns and precise activity predictions with 6.76% increase in F-measure. All this collectively help in understanding the users” actions to gain knowledge about their habits and preferences. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle An Incremental Target-Adapted Strategy for Active Geometric Calibration of Projector-Camera Systems
Sensors 2013, 13(2), 2664-2681; https://doi.org/10.3390/s130202664
Received: 11 January 2013 / Revised: 11 February 2013 / Accepted: 15 February 2013 / Published: 22 February 2013
Cited by 13 | PDF Full-text (2169 KB) | HTML Full-text | XML Full-text
Abstract
The calibration of a projector-camera system is an essential step toward accurate 3-D measurement and environment-aware data projection applications, such as augmented reality. In this paper we present a two-stage easy-to-deploy strategy for robust calibration of both intrinsic and extrinsic parameters of a
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The calibration of a projector-camera system is an essential step toward accurate 3-D measurement and environment-aware data projection applications, such as augmented reality. In this paper we present a two-stage easy-to-deploy strategy for robust calibration of both intrinsic and extrinsic parameters of a projector. Two key components of the system are the automatic generation of projected light patterns and the incremental calibration process. Based on the incremental strategy, the calibration process first establishes a set of initial parameters, and then it upgrades these parameters incrementally using the projection and captured images of dynamically-generated calibration patterns. The scene-driven light patterns allow the system to adapt itself to the pose of the calibration target, such that the difficulty in feature detection is greatly lowered. The strategy forms a closed-loop system that performs self-correction as more and more observations become available. Compared to the conventional method, which requires a time-consuming process for the acquisition of dense pixel correspondences, the proposed method deploys a homography-based coordinate computation, allowing the calibration time to be dramatically reduced. The experimental results indicate that an improvement of 70% in reprojection errors is achievable and 95% of the calibration time can be saved. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle Autonomous Docking Based on Infrared System for Electric Vehicle Charging in Urban Areas
Sensors 2013, 13(2), 2645-2663; https://doi.org/10.3390/s130202645
Received: 11 December 2012 / Revised: 24 January 2013 / Accepted: 5 February 2013 / Published: 21 February 2013
Cited by 12 | PDF Full-text (1283 KB) | HTML Full-text | XML Full-text
Abstract
Electric vehicles are progressively introduced in urban areas, because of their ability to reduce air pollution, fuel consumption and noise nuisance. Nowadays, some big cities are launching the first electric car-sharing projects to clear traffic jams and enhance urban mobility, as an alternative
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Electric vehicles are progressively introduced in urban areas, because of their ability to reduce air pollution, fuel consumption and noise nuisance. Nowadays, some big cities are launching the first electric car-sharing projects to clear traffic jams and enhance urban mobility, as an alternative to the classic public transportation systems. However, there are still some problems to be solved related to energy storage, electric charging and autonomy. In this paper, we present an autonomous docking system for electric vehicles recharging based on an embarked infrared camera performing infrared beacons detection installed in the infrastructure. A visual servoing system coupled with an automatic controller allows the vehicle to dock accurately to the recharging booth in a street parking area. The results show good behavior of the implemented system, which is currently deployed as a real prototype system in the city of Paris. Full article
(This article belongs to the Special Issue New Trends towards Automatic Vehicle Control and Perception Systems)
Open AccessArticle On the Effects of the Lateral Strains on the Fiber Bragg Grating Response
Sensors 2013, 13(2), 2631-2644; https://doi.org/10.3390/s130202631
Received: 6 December 2012 / Revised: 6 February 2013 / Accepted: 13 February 2013 / Published: 21 February 2013
Cited by 16 | PDF Full-text (822 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, a combined experimental-numerical based work was undertaken to investigate the Bragg wavelength shift response of an embedded FBG sensor when subjected to different conditions of multi-axial loading (deformation). The following cases are examined: (a) when an isotropic host material with
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In this paper, a combined experimental-numerical based work was undertaken to investigate the Bragg wavelength shift response of an embedded FBG sensor when subjected to different conditions of multi-axial loading (deformation). The following cases are examined: (a) when an isotropic host material with no constrains on planes normal to the embedded sensor’s axis is biaxially loaded, (b) when the same isotropic host material is subjected to hydrostatic pressure and (c) when the hydrostatically loaded host material is an anisotropic one, as in the case of a composite material, where the optical fiber is embedded along the reinforcing fibers. The comparison of the experimental results and the finite element simulations shows that, when the axial strain on the FBG sensor is the dominant component, the standard wavelength-shift strain relation can be used even if large lateral strains apply on the sensor. However when this is not the case, large errors may be introduced in the conversion of the wavelength to axial strains on the fiber. This situation arises when the FBG is placed parallel to high modulus reinforcing fibers of a polymer composite. Full article
(This article belongs to the Special Issue Laser Sensing and Imaging)
Open AccessArticle A Neuro-Fuzzy System for Characterization of Arm Movements
Sensors 2013, 13(2), 2613-2630; https://doi.org/10.3390/s130202613
Received: 13 December 2012 / Revised: 15 February 2013 / Accepted: 16 February 2013 / Published: 21 February 2013
Cited by 12 | PDF Full-text (705 KB) | HTML Full-text | XML Full-text
Abstract
The myoelectric signal reflects the electrical activity of skeletal muscles and contains information about the structure and function of the muscles which make different parts of the body move. Advances in engineering have extended electromyography beyond the traditional diagnostic applications to also include
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The myoelectric signal reflects the electrical activity of skeletal muscles and contains information about the structure and function of the muscles which make different parts of the body move. Advances in engineering have extended electromyography beyond the traditional diagnostic applications to also include applications in diverse areas such as rehabilitation, movement analysis and myoelectric control of prosthesis. This paper aims to study and develop a system that uses myoelectric signals, acquired by surface electrodes, to characterize certain movements of the human arm. To recognize certain hand-arm segment movements, was developed an algorithm for pattern recognition technique based on neuro-fuzzy, representing the core of this research. This algorithm has as input the preprocessed myoelectric signal, to disclosed specific characteristics of the signal, and as output the performed movement. The average accuracy obtained was 86% to 7 distinct movements in tests of long duration (about three hours). Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle Virtual and Remote Robotic Laboratory Using EJS, MATLAB and LabVIEW
Sensors 2013, 13(2), 2595-2612; https://doi.org/10.3390/s130202595
Received: 28 December 2012 / Revised: 1 February 2013 / Accepted: 16 February 2013 / Published: 21 February 2013
Cited by 37 | PDF Full-text (1289 KB) | HTML Full-text | XML Full-text
Abstract
This paper describes the design and implementation of a virtual and remote laboratory based on Easy Java Simulations (EJS) and LabVIEW. The main application of this laboratory is to improve the study of sensors in Mobile Robotics, dealing with the problems that arise
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This paper describes the design and implementation of a virtual and remote laboratory based on Easy Java Simulations (EJS) and LabVIEW. The main application of this laboratory is to improve the study of sensors in Mobile Robotics, dealing with the problems that arise on the real world experiments. This laboratory allows the user to work from their homes, tele-operating a real robot that takes measurements from its sensors in order to obtain a map of its environment. In addition, the application allows interacting with a robot simulation (virtual laboratory) or with a real robot (remote laboratory), with the same simple and intuitive graphical user interface in EJS. Thus, students can develop signal processing and control algorithms for the robot in simulation and then deploy them on the real robot for testing purposes. Practical examples of application of the laboratory on the inter-University Master of Systems Engineering and Automatic Control are presented. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessArticle Wedge-Filtering of Geomorphologic Terrestrial Laser Scan Data
Sensors 2013, 13(2), 2579-2594; https://doi.org/10.3390/s130202579
Received: 4 January 2013 / Revised: 4 February 2013 / Accepted: 8 February 2013 / Published: 20 February 2013
Cited by 9 | PDF Full-text (1559 KB) | HTML Full-text | XML Full-text
Abstract
Terrestrial laser scanning is of increasing importance for surveying and hazard assessments. Digital terrain models are generated using the resultant data to analyze surface processes. In order to determine the terrain surface as precisely as possible, it is often necessary to filter out
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Terrestrial laser scanning is of increasing importance for surveying and hazard assessments. Digital terrain models are generated using the resultant data to analyze surface processes. In order to determine the terrain surface as precisely as possible, it is often necessary to filter out points that do not represent the terrain surface. Examples are vegetation, vehicles, and animals. Filtering in mountainous terrain is more difficult than in other topography types. Here, existing automatic filtering solutions are not acceptable, because they are usually designed for airborne scan data. The present article describes a method specifically suitable for filtering terrestrial laser scanning data. This method is based on the direct line of sight between the scanner and the measured point and the assumption that no other surface point can be located in the area above this connection line. This assumption is only true for terrestrial laser data, but not for airborne data. We present a comparison of the wedge filtering to a modified inverse distance filtering method (IDWMO) filtered point cloud data. Both methods use manually filtered surfaces as reference. The comparison shows that the mean error and root–mean-square-error (RSME) between the results and the manually filtered surface of the two methods are similar. A significantly higher number of points of the terrain surface could be preserved, however, using the wedge-filtering approach. Therefore, we suggest that wedge-filtering should be integrated as a further parameter into already existing filtering processes, but is not suited as a standalone solution so far. Full article
(This article belongs to the Special Issue Laser Sensing and Imaging)
Open AccessArticle Photonic Crystal Biosensor Based on Optical Surface Waves
Sensors 2013, 13(2), 2566-2578; https://doi.org/10.3390/s130202566
Received: 11 January 2013 / Revised: 7 February 2013 / Accepted: 8 February 2013 / Published: 19 February 2013
Cited by 34 | PDF Full-text (2703 KB) | HTML Full-text | XML Full-text
Abstract
A label-free biosensor device based on registration of photonic crystal surface waves is described. Angular interrogation of the optical surface wave resonance is used to detect changes in the thickness of an adsorbed layer, while an additional simultaneous detection of the critical angle
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A label-free biosensor device based on registration of photonic crystal surface waves is described. Angular interrogation of the optical surface wave resonance is used to detect changes in the thickness of an adsorbed layer, while an additional simultaneous detection of the critical angle of total internal reflection provides independent data of the liquid refractive index. The abilities of the device are demonstrated by measuring of biotin molecule binding to a streptavidin monolayer, and by measuring association and dissociation kinetics of immunoglobulin G proteins. Additionally, deposition of PSS / PAH polyelectrolytes is recorded in situ resulting calculation of PSS and PAH monolayer thicknesses separately. Full article
(This article belongs to the Special Issue Photonic Crystal Sensors)
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Open AccessArticle A Novel Two-Axis Load Sensor Designed for in Situ Scratch Testing inside Scanning Electron Microscopes
Sensors 2013, 13(2), 2552-2565; https://doi.org/10.3390/s130202552
Received: 16 December 2012 / Revised: 29 January 2013 / Accepted: 29 January 2013 / Published: 18 February 2013
Cited by 1 | PDF Full-text (799 KB) | HTML Full-text | XML Full-text
Abstract
Because of a lack of available miniaturized multiaxial load sensors to measure the normal load and the lateral load simultaneously, quantitative in situ scratch devices inside scanning electron microscopes and the transmission electron microscopes have barely been developed up to now. A novel
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Because of a lack of available miniaturized multiaxial load sensors to measure the normal load and the lateral load simultaneously, quantitative in situ scratch devices inside scanning electron microscopes and the transmission electron microscopes have barely been developed up to now. A novel two-axis load sensor was designed in this paper. With an I-shaped structure, the sensor has the function of measuring the lateral load and the normal load simultaneously, and at the same time it has compact dimensions. Finite element simulations were carried out to evaluate stiffness and modal characteristics. A decoupling algorithm was proposed to resolve the cross-coupling between the two-axis loads. Natural frequency of the sensor was tested. Linearity and decoupling parameters were obtained from the calibration experiments, which indicate that the sensor has good linearity and the cross-coupling between the two axes is not strong. Via the decoupling algorithm and the corresponding decoupling parameters, simultaneous measurement of the lateral load and the normal load can be realized via the developed two-axis load sensor. Preliminary applications of the load sensor for scratch testing indicate that the load sensor can work well during the scratch testing. Taking advantage of the compact structure, it has the potential ability for applications in quantitative in situ scratch testing inside SEMs. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle Heart Sound Biometric System Based on Marginal Spectrum Analysis
Sensors 2013, 13(2), 2530-2551; https://doi.org/10.3390/s130202530
Received: 14 November 2012 / Revised: 28 January 2013 / Accepted: 4 February 2013 / Published: 18 February 2013
Cited by 14 | PDF Full-text (673 KB) | HTML Full-text | XML Full-text
Abstract
This work presents a heart sound biometric system based on marginal spectrum analysis, which is a new feature extraction technique for identification purposes. This heart sound identification system is comprised of signal acquisition, pre-processing, feature extraction, training, and identification. Experiments on the selection
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This work presents a heart sound biometric system based on marginal spectrum analysis, which is a new feature extraction technique for identification purposes. This heart sound identification system is comprised of signal acquisition, pre-processing, feature extraction, training, and identification. Experiments on the selection of the optimal values for the system parameters are conducted. The results indicate that the new spectrum coefficients result in a significant increase in the recognition rate of 94.40% compared with that of the traditional Fourier spectrum (84.32%) based on a database of 280 heart sounds from 40 participants. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessArticle Forgery Detection and Value Identification of Euro Banknotes
Sensors 2013, 13(2), 2515-2529; https://doi.org/10.3390/s130202515
Received: 18 December 2012 / Revised: 29 January 2013 / Accepted: 4 February 2013 / Published: 18 February 2013
Cited by 13 | PDF Full-text (1532 KB) | HTML Full-text | XML Full-text
Abstract
This paper describes both hardware and software components to detect counterfeits of Euro banknotes. The proposed system is also able to recognize the banknote values. Differently than other state-of-the-art methods, the proposed approach makes use of banknote images acquired with a near infrared
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This paper describes both hardware and software components to detect counterfeits of Euro banknotes. The proposed system is also able to recognize the banknote values. Differently than other state-of-the-art methods, the proposed approach makes use of banknote images acquired with a near infrared camera to perform recognition and authentication. This allows one to build a system that can effectively deal with real forgeries, which are usually not detectable with visible light. The hardware does not use any mechanical parts, so the overall system is low-cost. The proposed solution is reliable for ambient light and banknote positioning. Users should simply lean the banknote to be analyzed on a flat glass, and the system detects forgery, as well as recognizes the banknote value. The effectiveness of the proposed solution has been properly tested on a dataset composed by genuine and fake Euro banknotes provided by Italy's central bank. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle High Throughput Molecular Confirmation of β-Thalassemia Mutations Using Novel TaqMan Probes
Sensors 2013, 13(2), 2506-2514; https://doi.org/10.3390/s130202506
Received: 22 November 2012 / Revised: 25 January 2013 / Accepted: 6 February 2013 / Published: 18 February 2013
Cited by 6 | PDF Full-text (906 KB) | HTML Full-text | XML Full-text
Abstract
β-Thalassemia is a public health problem where 4.5% of Malaysians are β-thalassemia carriers. The genetic disorder is caused by defects in the β-globin gene complex which lead to reduced or complete absence of β-globin chain synthesis. Five TaqMan genotyping assays were designed and
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β-Thalassemia is a public health problem where 4.5% of Malaysians are β-thalassemia carriers. The genetic disorder is caused by defects in the β-globin gene complex which lead to reduced or complete absence of β-globin chain synthesis. Five TaqMan genotyping assays were designed and developed to detect the common β-thalassemia mutations in Malaysian Malays. The assays were evaluated with 219 "blinded" DNA samples and the results showed 100% sensitivity and specificity. The in-house designed TaqMan genotyping assays were found to be cost- and time-effective for characterization of β-thalassemia mutations in the Malaysian population. Full article
(This article belongs to the Section Biosensors)
Open AccessArticle Hardware Implementation of Lorenz Circuit Systems for Secure Chaotic Communication Applications
Sensors 2013, 13(2), 2494-2505; https://doi.org/10.3390/s130202494
Received: 4 January 2013 / Revised: 7 February 2013 / Accepted: 8 February 2013 / Published: 18 February 2013
Cited by 8 | PDF Full-text (508 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents the synchronization between the master and slave Lorenz chaotic systems by slide mode controller (SMC)-based technique. A proportional-integral (PI) switching surface is proposed to simplify the task of assigning the performance of the closed-loop error system in sliding mode. Then,
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This paper presents the synchronization between the master and slave Lorenz chaotic systems by slide mode controller (SMC)-based technique. A proportional-integral (PI) switching surface is proposed to simplify the task of assigning the performance of the closed-loop error system in sliding mode. Then, extending the concept of equivalent control and using some basic electronic components, a secure communication system is constructed. Experimental results show the feasibility of synchronizing two Lorenz circuits via the proposed SMC. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle Detection of Micrococcus Luteus Biofilm Formation in Microfluidic Environments by pH Measurement Using an Ion-Sensitive Field-Effect Transistor
Sensors 2013, 13(2), 2484-2493; https://doi.org/10.3390/s130202484
Received: 26 December 2012 / Revised: 8 February 2013 / Accepted: 10 February 2013 / Published: 18 February 2013
Cited by 9 | PDF Full-text (653 KB) | HTML Full-text | XML Full-text
Abstract
Biofilm formation in microfluidic channels is difficult to detect because sampling volumes are too small for conventional turbidity measurements. To detect biofilm formation, we used an ion-sensitive field-effect transistor (ISFET) measurement system to measure pH changes in small volumes of bacterial suspension. Cells
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Biofilm formation in microfluidic channels is difficult to detect because sampling volumes are too small for conventional turbidity measurements. To detect biofilm formation, we used an ion-sensitive field-effect transistor (ISFET) measurement system to measure pH changes in small volumes of bacterial suspension. Cells of Micrococcus luteus (M. luteus) were cultured in polystyrene (PS) microtubes and polymethylmethacrylate (PMMA)-based microfluidic channels laminated with polyvinylidene chloride. In microtubes, concentrations of bacteria and pH in the suspension were analyzed by measuring turbidity and using an ISFET sensor, respectively. In microfluidic channels containing 20 μL of bacterial suspension, we measured pH changes using the ISFET sensor and monitored biofilm formation using a microscope. We detected acidification and alkalinization phases of M. luteus from the ISFET sensor signals in both microtubes and microfluidic channels. In the alkalinization phase, after 2 day culture, dense biofilm formation was observed at the bottom of the microfluidic channels. In this study, we used an ISFET sensor to detect biofilm formation in clinical and industrial microfluidic environments by detecting alkalinization of the culture medium. Full article
(This article belongs to the Special Issue Microfluidic Devices)
Open AccessArticle Performance Enhancement of a GaAs Detector with a Vertical Field and an Embedded Thin Low-Temperature Grown Layer
Sensors 2013, 13(2), 2475-2483; https://doi.org/10.3390/s130202475
Received: 17 December 2012 / Revised: 6 February 2013 / Accepted: 8 February 2013 / Published: 18 February 2013
Cited by 4 | PDF Full-text (432 KB) | HTML Full-text | XML Full-text
Abstract
Low temperature growth of GaAs (LT-GaAs) near 200 °C results in a recombination lifetime of nearly 1 ps, compared with approximately 1 ns for regular temperature ~600 °C grown GaAs (RT-GaAs), making it suitable for ultra high speed detection applications. However, LT-GaAs detectors
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Low temperature growth of GaAs (LT-GaAs) near 200 °C results in a recombination lifetime of nearly 1 ps, compared with approximately 1 ns for regular temperature ~600 °C grown GaAs (RT-GaAs), making it suitable for ultra high speed detection applications. However, LT-GaAs detectors usually suffer from low responsivity due to low carrier mobility. Here we report electro-optic sampling time response measurements of a detector that employs an AlGaAs heterojunction, a thin layer of LT-GaAs, a channel of RT-GaAs, and a vertical electric field that together facilitate collection of optically generated electrons while suppressing collection of lower mobility holes. Consequently, these devices have detection efficiency near that of RT-GaAs yet provide pulse widths nearly an order of magnitude faster—~6 ps for a cathode-anode separation of 1.3 μm and ~12 ps for distances more than 3 μm. Full article
(This article belongs to the Special Issue Photodetectors)
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