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Sensors, Volume 11, Issue 9 (September 2011), Pages 8203-9120

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Open AccessArticle Impact of the Excitation Source and Plasmonic Material on Cylindrical Active Coated Nano-Particles
Sensors 2011, 11(9), 9109-9120; https://doi.org/10.3390/s110909109
Received: 23 July 2011 / Revised: 23 August 2011 / Accepted: 20 September 2011 / Published: 21 September 2011
Cited by 16 | PDF Full-text (1202 KB) | HTML Full-text | XML Full-text
Abstract
Electromagnetic properties of cylindrical active coated nano-particles comprised of a silica nano-cylinder core layered with a plasmonic concentric nano-shell are investigated for potential nano-sensor applications. Particular attention is devoted to the near-field properties of these particles, as well as to their far-field radiation
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Electromagnetic properties of cylindrical active coated nano-particles comprised of a silica nano-cylinder core layered with a plasmonic concentric nano-shell are investigated for potential nano-sensor applications. Particular attention is devoted to the near-field properties of these particles, as well as to their far-field radiation characteristics, in the presence of an electric or a magnetic line source. A constant frequency canonical gain model is used to account for the gain introduced in the dielectric part of the nano-particle, whereas three different plasmonic materials (silver, gold, and copper) are employed and compared for the nano-shell layers. Full article
(This article belongs to the Special Issue Metamaterials for Sensing)
Open AccessArticle Direction-of-Arrival Estimation Based on Joint Sparsity
Sensors 2011, 11(9), 9098-9108; https://doi.org/10.3390/s110909098
Received: 16 August 2011 / Revised: 17 September 2011 / Accepted: 18 September 2011 / Published: 21 September 2011
Cited by 6 | PDF Full-text (311 KB) | HTML Full-text | XML Full-text
Abstract
We present a DOA estimation algorithm, called Joint-Sparse DOA to address the problem of Direction-of-Arrival (DOA) estimation using sensor arrays. Firstly, DOA estimation is cast as the joint-sparse recovery problem. Then, norm is approximated by an arctan function to represent joint sparsity and
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We present a DOA estimation algorithm, called Joint-Sparse DOA to address the problem of Direction-of-Arrival (DOA) estimation using sensor arrays. Firstly, DOA estimation is cast as the joint-sparse recovery problem. Then, norm is approximated by an arctan function to represent joint sparsity and DOA estimation can be obtained by minimizing the approximate norm. Finally, the minimization problem is solved by a quasi-Newton method to estimate DOA. Simulation results show that our algorithm has some advantages over most existing methods: it needs a small number of snapshots to estimate DOA, while the number of sources need not be known a priori. Besides, it improves the resolution, and it can also handle the coherent sources well. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle Geometric Calibration and Radiometric Correction of LiDAR Data and Their Impact on the Quality of Derived Products
Sensors 2011, 11(9), 9069-9097; https://doi.org/10.3390/s110909069
Received: 22 June 2011 / Revised: 1 September 2011 / Accepted: 3 September 2011 / Published: 21 September 2011
Cited by 21 | PDF Full-text (1136 KB) | HTML Full-text | XML Full-text
Abstract
LiDAR (Light Detection And Ranging) systems are capable of providing 3D positional and spectral information (in the utilized spectrum range) of the mapped surface. Due to systematic errors in the system parameters and measurements, LiDAR systems require geometric calibration and radiometric correction of
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LiDAR (Light Detection And Ranging) systems are capable of providing 3D positional and spectral information (in the utilized spectrum range) of the mapped surface. Due to systematic errors in the system parameters and measurements, LiDAR systems require geometric calibration and radiometric correction of the intensity data in order to maximize the benefit from the collected positional and spectral information. This paper presents a practical approach for the geometric calibration of LiDAR systems and radiometric correction of collected intensity data while investigating their impact on the quality of the derived products. The proposed approach includes the use of a quasi-rigorous geometric calibration and the radar equation for the radiometric correction of intensity data. The proposed quasi-rigorous calibration procedure requires time-tagged point cloud and trajectory position data, which are available to most of the data users. The paper presents a methodology for evaluating the impact of the geometric calibration on the relative and absolute accuracy of the LiDAR point cloud. Furthermore, the impact of the geometric calibration and radiometric correction on land cover classification accuracy is investigated. The feasibility of the proposed methods and their impact on the derived products are demonstrated through experimental results using real data. Full article
(This article belongs to the Section Remote Sensors)
Open AccessArticle A Framework for UWB-Based Communication and Location Tracking Systems for Wireless Sensor Networks
Sensors 2011, 11(9), 9045-9068; https://doi.org/10.3390/s110909045
Received: 10 August 2011 / Revised: 10 September 2011 / Accepted: 20 September 2011 / Published: 21 September 2011
Cited by 11 | PDF Full-text (559 KB) | HTML Full-text | XML Full-text
Abstract
Ultra wideband (UWB) radio technology is nowadays one of the most promising technologies for medium-short range communications. It has a wide range of applications including Wireless Sensor Networks (WSN) with simultaneous data transmission and location tracking. The combination of location and data transmission
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Ultra wideband (UWB) radio technology is nowadays one of the most promising technologies for medium-short range communications. It has a wide range of applications including Wireless Sensor Networks (WSN) with simultaneous data transmission and location tracking. The combination of location and data transmission is important in order to increase flexibility and reduce the cost and complexity of the system deployment. In this scenario, accuracy is not the only evaluation criteria, but also the amount of resources associated to the location service, as it has an impact not only on the location capacity of the system but also on the sensor data transmission capacity. Although several studies can be found in the literature addressing UWB-based localization, these studies mainly focus on distance estimation and position calculation algorithms. Practical aspects such as the design of the functional architecture, the procedure for the transmission of the associated information between the different elements of the system, and the need of tracking multiple terminals simultaneously in various application scenarios, are generally omitted. This paper provides a complete system level evaluation of a UWB-based communication and location system for Wireless Sensor Networks, including aspects such as UWB-based ranging, tracking algorithms, latency, target mobility and MAC layer design. With this purpose, a custom simulator has been developed, and results with real UWB equipment are presented too. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessArticle The Design of RFID Conveyor Belt Gate Systems Using an Antenna Control Unit
Sensors 2011, 11(9), 9033-9044; https://doi.org/10.3390/s110909033
Received: 21 August 2011 / Revised: 13 September 2011 / Accepted: 20 September 2011 / Published: 21 September 2011
Cited by 2 | PDF Full-text (466 KB) | HTML Full-text | XML Full-text
Abstract
This paper proposes an efficient management system utilizing a Radio Frequency Identification (RFID) antenna control unit which is moving along with the path of boxes of materials on the conveyor belt by manipulating a motor. The proposed antenna control unit, which is driven
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This paper proposes an efficient management system utilizing a Radio Frequency Identification (RFID) antenna control unit which is moving along with the path of boxes of materials on the conveyor belt by manipulating a motor. The proposed antenna control unit, which is driven by a motor and is located on top of the gate, has an array structure of two antennas with parallel connection. The array structure helps improve the directivity of antenna beam pattern and the readable RFID distance due to its configuration. In the experiments, as the control unit follows moving materials, the reading time has been improved by almost three-fold compared to an RFID system employing conventional fixed antennas. The proposed system also has a recognition rate of over 99% without additional antennas for detecting the sides of a box of materials. The recognition rate meets the conditions recommended by the Electronic Product Code glbal network (EPC)global for commercializing the system, with three antennas at a 20 dBm power of reader and a conveyor belt speed of 3.17 m/s. This will enable a host of new RFID conveyor belt gate systems with increased performance. Full article
(This article belongs to the Special Issue Selected Papers from FGIT 2010)
Open AccessArticle A Programmable Plug & Play Sensor Interface for WSN Applications
Sensors 2011, 11(9), 9009-9032; https://doi.org/10.3390/s110909009
Received: 4 August 2011 / Revised: 6 September 2011 / Accepted: 15 September 2011 / Published: 21 September 2011
Cited by 1 | PDF Full-text (1218 KB) | HTML Full-text | XML Full-text
Abstract
Cost reduction in wireless sensor networks (WSN) becomes a priority when extending their application to fields where a great number of sensors is needed, such as habitat monitoring, precision agriculture or diffuse greenhouse emission measurement. In these cases, the use of smart sensors
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Cost reduction in wireless sensor networks (WSN) becomes a priority when extending their application to fields where a great number of sensors is needed, such as habitat monitoring, precision agriculture or diffuse greenhouse emission measurement. In these cases, the use of smart sensors is expensive, consequently requiring the use of low-cost sensors. The solution to convert such generic low-cost sensors into intelligent ones leads to the implementation of a versatile system with enhanced processing and storage capabilities to attain a plug and play electronic interface able to adapt to all the sensors used. This paper focuses on this issue and presents a low-voltage plug & play reprogrammable interface capable of adapting to different sensor types and achieving an optimum reading performance for every sensor. The proposed interface, which includes both electronic and software elements so that it can be easily integrated in WSN nodes, is described and experimental test results to validate its performance are given. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessArticle Integrating Millimeter Wave Radar with a Monocular Vision Sensor for On-Road Obstacle Detection Applications
Sensors 2011, 11(9), 8992-9008; https://doi.org/10.3390/s110908992
Received: 19 August 2011 / Revised: 15 September 2011 / Accepted: 15 September 2011 / Published: 21 September 2011
Cited by 31 | PDF Full-text (2218 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a systematic scheme for fusing millimeter wave (MMW) radar and a monocular vision sensor for on-road obstacle detection. As a whole, a three-level fusion strategy based on visual attention mechanism and driver’s visual consciousness is provided for MMW radar and
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This paper presents a systematic scheme for fusing millimeter wave (MMW) radar and a monocular vision sensor for on-road obstacle detection. As a whole, a three-level fusion strategy based on visual attention mechanism and driver’s visual consciousness is provided for MMW radar and monocular vision fusion so as to obtain better comprehensive performance. Then an experimental method for radar-vision point alignment for easy operation with no reflection intensity of radar and special tool requirements is put forward. Furthermore, a region searching approach for potential target detection is derived in order to decrease the image processing time. An adaptive thresholding algorithm based on a new understanding of shadows in the image is adopted for obstacle detection, and edge detection is used to assist in determining the boundary of obstacles. The proposed fusion approach is verified through real experimental examples of on-road vehicle/pedestrian detection. In the end, the experimental results show that the proposed method is simple and feasible. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessArticle A Real-Time Capable Software-Defined Receiver Using GPU for Adaptive Anti-Jam GPS Sensors
Sensors 2011, 11(9), 8966-8991; https://doi.org/10.3390/s110908966
Received: 22 July 2011 / Revised: 14 September 2011 / Accepted: 16 September 2011 / Published: 19 September 2011
Cited by 19 | PDF Full-text (995 KB) | HTML Full-text | XML Full-text
Abstract
Due to their weak received signal power, Global Positioning System (GPS) signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference
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Due to their weak received signal power, Global Positioning System (GPS) signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs). However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR) with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU) coupled with a new generation Graphics Processing Unit (GPU) having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle A Guided Mode Resonance Aptasensor for Thrombin Detection
Sensors 2011, 11(9), 8953-8965; https://doi.org/10.3390/s110908953
Received: 21 July 2011 / Revised: 27 August 2011 / Accepted: 15 September 2011 / Published: 19 September 2011
Cited by 17 | PDF Full-text (791 KB) | HTML Full-text | XML Full-text
Abstract
Recent developments in aptamers have led to their widespread use in analytical and diagnostic applications, particularly for biosensing. Previous studies have combined aptamers as ligands with various sensors for numerous applications. However, merging the aptamer developments with guided mode resonance (GMR) devices has
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Recent developments in aptamers have led to their widespread use in analytical and diagnostic applications, particularly for biosensing. Previous studies have combined aptamers as ligands with various sensors for numerous applications. However, merging the aptamer developments with guided mode resonance (GMR) devices has not been attempted. This study reports an aptasensor based home built GMR device. The 29-mer thrombin aptamer was immobilized on the surface of a GMR device as a recognizing ligand for thrombin detection. The sensitivity reported in this first trial study is 0.04 nm/μM for thrombin detection in the concentration range from 0.25 to 1 μM and the limit of detection (LOD) is 0.19 μM. Furthermore, the binding affinity constant (Ka) measured is in the range of 106 M−1. The investigation has demonstrated that such a GMR aptasensor has the required sensitivity for the real time, label-free, in situ detection of thrombin and provides kinetic information related to the binding. Full article
(This article belongs to the Special Issue Aptamer-Based Sensors)
Open AccessArticle A Novel Design of an Automatic Lighting Control System for a Wireless Sensor Network with Increased Sensor Lifetime and Reduced Sensor Numbers
Sensors 2011, 11(9), 8933-8952; https://doi.org/10.3390/s110908933
Received: 2 August 2011 / Revised: 26 August 2011 / Accepted: 26 August 2011 / Published: 16 September 2011
Cited by 10 | PDF Full-text (2946 KB) | HTML Full-text | XML Full-text
Abstract
Wireless sensor networks (WSN) are currently being applied to energy conservation applications such as light control. We propose a design for such a system called a Lighting Automatic Control System (LACS). The LACS system contains a centralized or distributed architecture determined by application
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Wireless sensor networks (WSN) are currently being applied to energy conservation applications such as light control. We propose a design for such a system called a Lighting Automatic Control System (LACS). The LACS system contains a centralized or distributed architecture determined by application requirements and space usage. The system optimizes the calculations and communications for lighting intensity, incorporates user illumination requirements according to their activities and performs adjustments based on external lighting effects in external sensor and external sensor-less architectures. Methods are proposed for reducing the number of sensors required and increasing the lifetime of those used, for considerably reduced energy consumption. Additionally we suggest methods for improving uniformity of illuminance distribution on a workplane’s surface, which improves user satisfaction. Finally simulation results are presented to verify the effectiveness of our design. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessEditorial Advances in Sensors Applied to Agriculture and Forestry
Sensors 2011, 11(9), 8930-8932; https://doi.org/10.3390/s110908930
Received: 14 September 2011 / Accepted: 15 September 2011 / Published: 15 September 2011
Cited by 9 | PDF Full-text (119 KB) | HTML Full-text | XML Full-text
Abstract
In agriculture and forestry, the need to increase production and the simultaneous efforts to minimize the environmental impact of agricultural production processes and save costs find in sensor systems the best allied tool. The use of sensors helps exploit all available resources appropriately
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In agriculture and forestry, the need to increase production and the simultaneous efforts to minimize the environmental impact of agricultural production processes and save costs find in sensor systems the best allied tool. The use of sensors helps exploit all available resources appropriately and to apply hazardous products moderately. When nutrients in the soil, humidity, solar radiation, density of weeds and a broad set of factors and data affecting the production are known, this situation improves and the use of chemical products such as fertilizers, herbicides and other pollutants can be reduced considerably. Part of this knowledge allows also monitoring photosynthetic parameters of high relevance for photosynthesis. Most of the associated activities fall within the scope of what it is called Precision Agriculture, an emerging area receiving special attention in recent years. [...] Full article
(This article belongs to the Special Issue Sensors in Agriculture and Forestry)
Open AccessArticle Organic Pollution in Surface Waters from the Fuglebekken Basin in Svalbard, Norwegian Arctic
Sensors 2011, 11(9), 8910-8929; https://doi.org/10.3390/s110908910
Received: 8 August 2011 / Revised: 4 September 2011 / Accepted: 8 September 2011 / Published: 15 September 2011
Cited by 20 | PDF Full-text (631 KB) | HTML Full-text | XML Full-text
Abstract
The Fuglebekken basin is situated in the southern part of the island of Spitsbergen (Norwegian Arctic), on the Hornsund fjord (Wedel Jarlsberg Land). Surface water was collected from 24 tributaries (B1–B24) and from the main stream water in the Fuglebekken basin (25) between
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The Fuglebekken basin is situated in the southern part of the island of Spitsbergen (Norwegian Arctic), on the Hornsund fjord (Wedel Jarlsberg Land). Surface water was collected from 24 tributaries (B1–B24) and from the main stream water in the Fuglebekken basin (25) between 10 July 2009 and 30 July 2009. The present investigation reveals the results of the analysis of these samples for their PAH and PCB content. Twelve of 16 PAHs and seven PCBs were determined in the surface waters from 24 tributaries and the main stream. Total PAH and PCB concentrations in the surface waters ranged from 4 to 600 ng/L and from 2 to 400 ng/L respectively. The highest concentrations of an individual PCB (138–308 ng/L and 123 ng/L) were found in samples from tributaries B9 and B5. The presence in the basin (thousands of kilometres distant from industrial centres) of PAHs and PCBs is testimony to the fact that these compounds are transported over vast distances with air masses and deposited in regions devoid of any human pressure. Full article
(This article belongs to the Special Issue Sensing of Organic Pollution in Soil, Air, Water and Food)
Open AccessArticle Reconstruction of Self-Sparse 2D NMR Spectra from Undersampled Data in the Indirect Dimension
Sensors 2011, 11(9), 8888-8909; https://doi.org/10.3390/s110908888
Received: 31 July 2011 / Revised: 31 August 2011 / Accepted: 5 September 2011 / Published: 15 September 2011
Cited by 18 | PDF Full-text (2868 KB) | HTML Full-text | XML Full-text
Abstract
Reducing the acquisition time for two-dimensional nuclear magnetic resonance (2D NMR) spectra is important. One way to achieve this goal is reducing the acquired data. In this paper, within the framework of compressed sensing, we proposed to undersample the data in the indirect
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Reducing the acquisition time for two-dimensional nuclear magnetic resonance (2D NMR) spectra is important. One way to achieve this goal is reducing the acquired data. In this paper, within the framework of compressed sensing, we proposed to undersample the data in the indirect dimension for a type of self-sparse 2D NMR spectra, that is, only a few meaningful spectral peaks occupy partial locations, while the rest of locations have very small or even no peaks. The spectrum is reconstructed by enforcing its sparsity in an identity matrix domain with p (p = 0.5) norm optimization algorithm. Both theoretical analysis and simulation results show that the proposed method can reduce the reconstruction errors compared with the wavelet-based 1 norm optimization. Full article
(This article belongs to the Section Chemical Sensors)
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Open AccessArticle A Semantic Sensor Web for Environmental Decision Support Applications
Sensors 2011, 11(9), 8855-8887; https://doi.org/10.3390/s110908855
Received: 26 July 2011 / Revised: 29 August 2011 / Accepted: 29 August 2011 / Published: 14 September 2011
Cited by 21 | PDF Full-text (2275 KB) | HTML Full-text | XML Full-text
Abstract
Sensing devices are increasingly being deployed to monitor the physical world around us. One class of application for which sensor data is pertinent is environmental decision support systems, e.g., flood emergency response. For these applications, the sensor readings need to be put in
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Sensing devices are increasingly being deployed to monitor the physical world around us. One class of application for which sensor data is pertinent is environmental decision support systems, e.g., flood emergency response. For these applications, the sensor readings need to be put in context by integrating them with other sources of data about the surrounding environment. Traditional systems for predicting and detecting floods rely on methods that need significant human resources. In this paper we describe a semantic sensor web architecture for integrating multiple heterogeneous datasets, including live and historic sensor data, databases, and map layers. The architecture provides mechanisms for discovering datasets, defining integrated views over them, continuously receiving data in real-time, and visualising on screen and interacting with the data. Our approach makes extensive use of web service standards for querying and accessing data, and semantic technologies to discover and integrate datasets. We demonstrate the use of our semantic sensor web architecture in the context of a flood response planning web application that uses data from sensor networks monitoring the sea-state around the coast of England. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle Detailed Study of Amplitude Nonlinearity in Piezoresistive Force Sensors
Sensors 2011, 11(9), 8836-8854; https://doi.org/10.3390/s110908836
Received: 28 July 2011 / Revised: 8 September 2011 / Accepted: 9 September 2011 / Published: 14 September 2011
Cited by 10 | PDF Full-text (1507 KB) | HTML Full-text | XML Full-text
Abstract
This article upgrades the RC linear model presented for piezoresistive force sensors. Amplitude nonlinearity is found in sensor conductance, and a characteristic equation is formulated for modeling its response under DC-driving voltages below 1 V. The feasibility of such equation is tested on
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This article upgrades the RC linear model presented for piezoresistive force sensors. Amplitude nonlinearity is found in sensor conductance, and a characteristic equation is formulated for modeling its response under DC-driving voltages below 1 V. The feasibility of such equation is tested on four FlexiForce model A201-100 piezoresistive sensors by varying the sourcing voltage and the applied forces. Since the characteristic equation proves to be valid, a method is presented for obtaining a specific sensitivity in sensor response by calculating the appropriate sourcing voltage and feedback resistor in the driving circuit; this provides plug-and-play capabilities to the device and reduces the start-up time of new applications where piezoresistive devices are to be used. Finally, a method for bypassing the amplitude nonlinearity is presented with the aim of reading sensor capacitance. Full article
(This article belongs to the Section Physical Sensors)
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