Journal of Sensors http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. QoS and QoE Aware N-Screen Multicast Service Thu, 05 May 2016 10:52:11 +0000 http://www.hindawi.com/journals/js/2016/8040138/ The paper focuses on ensuring the quality-of-service (QoS) and quality-of-experience (QoE) requirements of users having heterogeneous devices in a multicast session. QoS parameters such as bit rate, delays, and packet losses are good indicators for optimizing network services but fall short in characterizing user perception (QoE). In N-Screen service, the users have different devices with heterogeneous attributes like screen size, resolution, and access network interface, and the users have different QoE on N-Screen devices with the same QoS parameters. We formulate the objective function of the N-Screen multicast grouping to ensure the minimum user’s QoE with smaller bandwidth requirement. We propose a dynamic user reassignment scheme to maintain and satisfy the QoE by adapting the user’s membership to the varying network conditions. The proposed schemes combine the available bandwidth and multimedia visual quality to ensure the QoS and QoE. In the network architecture, we introduce the functions of the QoS and QoE aware multicast group management and the estimation schemes for the QoS and QoE parameters. The simulation results show that the proposed multicast service ensures the network QoS and guarantees the QoE of users in the varying network conditions. Ghulam Sarwar, Farman Ullah, and Sungchang Lee Copyright © 2016 Ghulam Sarwar et al. All rights reserved. Energy Optimization for Outdoor Activity Recognition Thu, 05 May 2016 07:16:47 +0000 http://www.hindawi.com/journals/js/2016/6156914/ The mobile phone is no longer only a communication device, but also a powerful environmental sensing unit that can monitor a user’s ambient context. Mobile users take their devices with them everywhere which increases the availability of persons’ traces. Extracting and analyzing knowledge from these traces represent a strong support for several applications domains, ranging from traffic management to advertisement and social studies. However, the limited battery capacity of mobile devices represents a big hurdle for context detection, no matter how useful the service may be. We present a novel approach to online recognizing users’ outdoor activities without depleting the mobile resources. We associate the places visited by individuals during their movements with meaningful human activities using a novel algorithm that clusters incrementally user’s moves into different types of activities. To optimize the battery consumption, the algorithm behaves variably on the basis of users’ behaviors and the remaining battery level. Studies using real GPS records from two big datasets demonstrate that the proposal is effective and is capable of inferring human activities without draining the phone resources. Mehdi Boukhechba, Abdenour Bouzouane, Bruno Bouchard, Charles Gouin-Vallerand, and Sylvain Giroux Copyright © 2016 Mehdi Boukhechba et al. All rights reserved. Development of a Wireless Temperature Sensor Using Polymer-Derived Ceramics Wed, 04 May 2016 08:35:22 +0000 http://www.hindawi.com/journals/js/2016/8624817/ A temperature sensor has been developed using an embedded system and a sensor head made of polymer-derived SiAlCN ceramics (PDCs). PDC is a promising material for measuring high temperature and the embedded system features low-power consumption, compact size, and wireless transmission. The developed temperature sensor has been experimentally tested to demonstrate the possibility of using such sensors for real world applications. Ran Zhao, Gang Shao, Ni Li, Chengying Xu, and Linan An Copyright © 2016 Ran Zhao et al. All rights reserved. Experimental Method of Temperature and Strain Discrimination in Polymer Composite Material by Embedded Fiber-Optic Sensors Based on Femtosecond-Inscribed FBGs Thu, 28 Apr 2016 17:06:36 +0000 http://www.hindawi.com/journals/js/2016/3230968/ Experimental method of temperature and strain discrimination with fiber Bragg gratings (FBGs) sensors embedded in carbon fiber-reinforced plastic is proposed. The method is based on two-fiber technique, when two FBGs inscribed in different fibers with different sensitivities to strain and/or temperature are placed close to each other and act as a single sensing element. The nonlinear polynomial approximation of Bragg wavelength shift as a function of temperature and strain is presented for this method. The FBGs were inscribed with femtosecond laser by point-by-point inscription technique through polymer cladding of the fiber. The comparison of linear and nonlinear approximation accuracies for array of embedded sensors is performed. It is shown that the use of nonlinear approximation gives 1.5–2 times better accuracy. The obtained accuracies of temperature and strain measurements are 2.6–3.8°C and 50–83 με in temperature and strain range of 30–120°C and 0–400 με, respectively. Victor V. Shishkin, Vadim S. Terentyev, Denis S. Kharenko, Alexandr V. Dostovalov, Alexey A. Wolf, Victor A. Simonov, Mikhail Yu. Fedotov, Anton M. Shienok, Ivan S. Shelemba, and Sergey A. Babin Copyright © 2016 Victor V. Shishkin et al. All rights reserved. Experimental Study on Piezoelectric Energy Harvesting from Vortex-Induced Vibrations and Wake-Induced Vibrations Wed, 27 Apr 2016 14:17:46 +0000 http://www.hindawi.com/journals/js/2016/2673292/ A rigid circular cylinder with two piezoelectric beams attached on has been tested through vortex-induced vibrations (VIV) and wake-induced vibrations (WIV) by installing a big cylinder fixed upstream, in order to study the influence of the different flow-induced vibrations (FIV) types. The VIV test shows that the output voltage increases with the increases of load resistance; an optimal load resistance exists for the maximum output power. The WIV test shows that the vibration of the small cylinder is controlled by the vortex frequency of the large one. There is an optimal gap of the cylinders that can obtain the maximum output voltage and power. For a same energy harvesting device, WIV has higher power generation capacity; then the piezoelectric output characteristics can be effectively improved. Min Zhang and Junlei Wang Copyright © 2016 Min Zhang and Junlei Wang. All rights reserved. On Event/Time Triggered and Distributed Analysis of a WSN System for Event Detection, Using Fuzzy Logic Wed, 27 Apr 2016 08:43:06 +0000 http://www.hindawi.com/journals/js/2016/9350928/ Event detection in realistic WSN environments is a critical research domain, while the environmental monitoring comprises one of its most pronounced applications. Although efforts related to the environmental applications have been presented in the current literature, there is a significant lack of investigation on the performance of such systems, when applied in wireless environments. Aiming at addressing this shortage, in this paper an advanced multimodal approach is followed based on fuzzy logic. The proposed fuzzy inference system (FIS) is implemented on TelosB motes and evaluates the probability of fire detection while aiming towards power conservation. Additionally to a straightforward centralized approach, a distributed implementation of the above FIS is also proposed, aiming towards network congestion reduction while optimally distributing the energy consumption among network nodes so as to maximize network lifetime. Moreover this work proposes an event based execution of the aforementioned FIS aiming to further reduce the computational as well as the communication cost, compared to a periodical time triggered FIS execution. As a final contribution, performance metrics acquired from all the proposed FIS implementation techniques are thoroughly compared and analyzed with respect to critical network conditions aiming to offer realistic evaluation and thus objective conclusions’ extraction. Sofia Maria Dima, Christos Antonopoulos, and Stavros Koubias Copyright © 2016 Sofia Maria Dima et al. All rights reserved. A Method of Removing Reflected Highlight on Images Based on Polarimetric Imaging Tue, 26 Apr 2016 16:41:42 +0000 http://www.hindawi.com/journals/js/2016/9537320/ A method of removing reflected highlight is proposed on polarimetric imaging. Polarization images (0°, 45°, 90°, and 135°) and the reflection angle are required in this reflected light removal algorithm. This method is based on the physical model of reflection and refraction, and no additional image processing algorithm is necessary in this algorithm. Compared to traditional polarization method with single polarizer, restricted observation angle of Brewster is not demanded and multiple reflection areas of different polarization orientations can be removed simultaneously. Experimental results, respectively, demonstrate the features of this reflected light removal algorithm, and it can be considered very suitable in polarization remote sensing. Fanchao Yang, Xingjia Tang, Bingliang Hu, Ruyi Wei, Liang Kong, and Yong Li Copyright © 2016 Fanchao Yang et al. All rights reserved. Deployment of Wireless Sensor Networks for Oilfield Monitoring by Multiobjective Discrete Binary Particle Swarm Optimization Sun, 24 Apr 2016 15:38:11 +0000 http://www.hindawi.com/journals/js/2016/9358358/ The deployment problem of wireless sensor networks for real time oilfield monitoring is studied. As a characteristic of oilfield monitoring system, all sensor nodes have to be installed on designated spots. For the energy efficiency, some relay nodes and sink nodes are deployed as a delivery subsystem. The major concern of the construction of the monitoring system is the optimum placement of data delivery subsystem to ensure the full connectivity of the sensor nodes while keeping the construction cost as low as possible, with least construction and maintenance complexity. Due to the complicated landform of oilfields, in general, it is rather difficult to satisfy these requirements simultaneously. The deployment problem is formulated as a constrained multiobjective optimization problem and solved through a novel scheme based on multiobjective discrete binary particle swarm optimization to produce optimal solutions from the minimum financial cost to the minimum complexity of construction and maintenance. Simulation results validated that comparing to the three existing state-of-the-art algorithms, that is, NSGA-II, JGGA, and SPEA2, the proposed scheme is superior in locating the Pareto-optimal front and maintaining the diversity of the solutions, thus providing superior candidate solutions for the design of real time monitoring systems in oilfields. Zhen-Lun Yang, Angus Wu, and Hua-Qing Min Copyright © 2016 Zhen-Lun Yang et al. All rights reserved. Characteristics of Relocated Quiet Zones Using Virtual Microphone Algorithm in an Active Headrest System Mon, 18 Apr 2016 11:57:49 +0000 http://www.hindawi.com/journals/js/2016/5185242/ This study displays theoretical and experimental investigation on the characteristics of the relocated zone of quiet by a virtual microphone (VM) based filtered-x LMS (FxLMS) algorithm which can be embedded in a real-time digital controller for an active headrest system. The attenuation changes at the relocated zones of quiet by the variation of the distance between the ear and the error microphone are mainly examined. An active headrest system was implemented for the control experiment at a chair and consists of two (left and right) secondary loudspeakers, two error microphones, two observer microphones at ear positions in a HATS, and other electronics including a dSPACE 1401 controller. The VM based FxLMS algorithm achieved an attenuation of about 22 dB in the control experiment against a narrowband primary noise by the variation of the distance between the ear and the error microphone. The important factors for the algorithm are discussed as well. Seokhoon Ryu and Young-Sup Lee Copyright © 2016 Seokhoon Ryu and Young-Sup Lee. All rights reserved. Identifying and Correcting Step Losses in Single-Ended Fiber-Optic Distributed Temperature Sensing Data Mon, 18 Apr 2016 08:37:28 +0000 http://www.hindawi.com/journals/js/2016/7073619/ Fiber-optic distributed temperature sensing (DTS) makes it possible to observe temperatures on spatial scales as fine as centimeters and at frequencies up to 1 Hz. Over the past decade, fiber-optic DTS instruments have increasingly been employed to monitor environmental temperatures, from oceans to atmospheric monitoring. Because of the nature of environmental deployments, optical fibers deployed for research purposes often encounter step losses in the Raman spectra signal. Whether these phenomena occur due to cable damage or impingements, sharp bends in the deployed cable, or connections and splices, the step losses are usually not adequately addressed by the calibration routines provided by instrument manufacturers and can be overlooked in postprocessing calibration routines as well. Here we provide a method to identify and correct for the effects of step losses in raw Raman spectra data. The utility of the correction is demonstrated with case studies, including synthetic and laboratory data sets. Mark B. Hausner and Scott Kobs Copyright © 2016 Mark B. Hausner and Scott Kobs. All rights reserved. Dynamic Performance Analysis of the Towers of a Long-Span Bridge Based on GPS Monitoring Technique Mon, 18 Apr 2016 07:25:40 +0000 http://www.hindawi.com/journals/js/2016/7494817/ The present study investigates the parameter identification and the dynamic performance of a long-span bridge tower based on the output of a global positioning system (GPS) health monitoring system. The random decrement (RD) algorithm is used to estimate the tower displacement impulse response. Three methods are applied to extract the dynamic performance including least squares complex exponential (LSCE) method, Hilbert envelope method (HEM), and eigensystem realization algorithm (ERA). Results reveal that the HEM and LSCE method are more suitable to extract fundamental frequency and modal and damping ratios of the tower. Furthermore, the dynamic properties and statistical time series analysis of the GPS measurements illustrate that the traffic loads have a high significant impact on the semistatic and dynamic performances. Mosbeh R. Kaloop and Jong Wan Hu Copyright © 2016 Mosbeh R. Kaloop and Jong Wan Hu. All rights reserved. Lithography-Free, Low-Cost Method for Improving Photodiode Performance by Etching Silicon Nanocones as Antireflection Layer Mon, 18 Apr 2016 06:51:49 +0000 http://www.hindawi.com/journals/js/2016/4019864/ A three-step process has been demonstrated to improve the performance of photodiode by creating nanocone forest on the surface of photodiode as an antireflection layer. This high-throughput, low-cost process has been shown to decrease the reflectivity by 66.1%, enhance the quantum efficiency by 27%, and increase the responsivity by 25.7%. This low-cost manufacture process can be applied to increase the responsivity of silicon based photonic devices. Jing Jiang, Zhida Xu, Jiahao Lin, and Gang Logan Liu Copyright © 2016 Jing Jiang et al. All rights reserved. An Architecture Offering Mobile Pollution Sensing with High Spatial Resolution Thu, 14 Apr 2016 15:39:48 +0000 http://www.hindawi.com/journals/js/2016/1458147/ Mobile sensing is becoming the best option to monitor our environment due to its ease of use, high flexibility, and low price. In this paper, we present a mobile sensing architecture able to monitor different pollutants using low-end sensors. Although the proposed solution can be deployed everywhere, it becomes especially meaningful in crowded cities where pollution values are often high, being of great concern to both population and authorities. Our architecture is composed of three different modules: a mobile sensor for monitoring environment pollutants, an Android-based device for transferring the gathered data to a central server, and a central processing server for analyzing the pollution distribution. Moreover, we analyze different issues related to the monitoring process: (i) filtering captured data to reduce the variability of consecutive measurements; (ii) converting the sensor output to actual pollution levels; (iii) reducing the temporal variations produced by mobile sensing process; and (iv) applying interpolation techniques for creating detailed pollution maps. In addition, we study the best strategy to use mobile sensors by first determining the influence of sensor orientation on the captured values and then analyzing the influence of time and space sampling in the interpolation process. Oscar Alvear, Willian Zamora, Carlos Calafate, Juan-Carlos Cano, and Pietro Manzoni Copyright © 2016 Oscar Alvear et al. All rights reserved. Study on Relationship between Dielectric Constant and Water Content of Rock-Soil Mixture by Time Domain Reflectometry Thu, 14 Apr 2016 14:27:05 +0000 http://www.hindawi.com/journals/js/2016/2827890/ It is important to test water content of rock-soil mixtures efficiently and accurately to ensure both the quality control of compaction and assessment of the geotechnical engineering properties. To overcome time and energy wastage and probe insertion problems when using the traditional calibration method, a TDR coaxial test tube calibration arrangement using an upward infiltration method was designed. This arrangement was then used to study the influence of dry density, pore fluid conductivity, and soil/rock ratio on the relationship between water content and the dielectric constant of rock-soil mixtures. The results show that the empirical calibration equation forms for rock-soil mixtures can be the same as for soil materials. The effect of dry density on the calibration equation has the most significance and the influence of pore fluid conductivity can be ignored. The impact of variation of the soil/rock ratio can be neutralized by considering the effect of dry density in the calibration equation for the same kind of soil and rock. The empirical equations proposed by Zhao et al. show a good accuracy for rock-soil mixtures, indicating that the TDR method can be used to test gravimetric water content conveniently and efficiently without calibration in the field. Daosheng Ling, Yun Zhao, Yunlong Wang, and Bo Huang Copyright © 2016 Daosheng Ling et al. All rights reserved. An Efficient Image Enlargement Method for Image Sensors of Mobile in Embedded Systems Thu, 14 Apr 2016 13:11:36 +0000 http://www.hindawi.com/journals/js/2016/6370845/ Main challenges for image enlargement methods in embedded systems come from the requirements of good performance, low computational cost, and low memory usage. This paper proposes an efficient image enlargement method which can meet these requirements in embedded system. Firstly, to improve the performance of enlargement methods, this method extracts different kind of features for different morphologies with different approaches. Then, various dictionaries based on different kind of features are learned, which represent the image in a more efficient manner. Secondly, to accelerate the enlargement speed and reduce the memory usage, this method divides the atoms of each dictionary into several clusters. For each cluster, separate projection matrix is calculated. This method reformulates the problem as a least squares regression. The high-resolution (HR) images can be reconstructed based on a few projection matrixes. Numerous experiment results show that this method has advantages such as being efficient and real-time and having less memory cost. These advantages make this method easy to implement in mobile embedded system. Hua Hua, Xiaomin Yang, Binyu Yan, Kai Zhou, and Wei Lu Copyright © 2016 Hua Hua et al. All rights reserved. Ru-Based Thin Film Temperature Sensor for Space Environments: Microfabrication and Characterization under Total Ionizing Dose Thu, 14 Apr 2016 13:00:27 +0000 http://www.hindawi.com/journals/js/2016/6086752/ The paper shows the microfabrication processes of a Ruthenium-based resistance temperature detector and its behavior in response to irradiation at ambient temperature. The radiation test was done in a public hospital facility and followed the procedures based on the ESA specification ESCC 22900. The instrumentation system used for the test is detailed in the work describing the sensors resistance evolution before, during, and after the exposure. A total irradiation dose of 43 krad with 36 krad/h dose rate was applied and a subsequent characterization was performed once the Ru sensors were submitted to an 80°C annealing process during a period of 168 h. The experimental measurements have shown the stability of this sensor against total ionizing dose (TID) tests, not only in their resistance absolute values during the irradiation phase but also in the relative deviation from their values before irradiation. S. I. Ravelo Arias, D. Ramírez Muñoz, Susana Cardoso, and Paulo P. Freitas Copyright © 2016 S. I. Ravelo Arias et al. All rights reserved. A Centralized Energy Efficient Distance Based Routing Protocol for Wireless Sensor Networks Thu, 14 Apr 2016 11:48:03 +0000 http://www.hindawi.com/journals/js/2016/8313986/ Wireless sensor network (WSN) typically consists of a large number of low cost wireless sensor nodes which collect and send various messages to a base station (BS). WSN nodes are small battery powered devices having limited energy resources. Replacement of such energy resources is not easy for thousands of nodes as they are inaccessible to users after their deployment. This generates a requirement of energy efficient routing protocol for increasing network lifetime while minimizing energy consumption. Low Energy Adaptive Clustering Hierarchy (LEACH) is a widely used classic clustering algorithm in WSNs. In this paper, we propose a Centralized Energy Efficient Distance (CEED) based routing protocol to evenly distribute energy dissipation among all sensor nodes. We calculate optimum number of cluster heads based on LEACH’s energy dissipation model. We propose a distributed cluster head selection algorithm based on dissipated energy of a node and its distance to BS. Moreover, we extend our protocol by multihop routing scheme to reduce energy dissipated by nodes located far away from base station. The performance of CEED is compared with other protocols such as LEACH and LEACH with Distance Based Thresholds (LEACH-DT). Simulation results show that CEED is more energy efficient as compared to other protocols. Also it improves the network lifetime and stability period over the other protocols. Rohit D. Gawade and S. L. Nalbalwar Copyright © 2016 Rohit D. Gawade and S. L. Nalbalwar. All rights reserved. A Two-Dimensional CMUT Linear Array for Underwater Applications: Directivity Analysis and Design Optimization Wed, 13 Apr 2016 07:44:55 +0000 http://www.hindawi.com/journals/js/2016/5298197/ Capacitive micromachined ultrasonic transducers (CMUTs) are one of the promising MEMS devices. This paper proposed an integrated vibration membrane structure to design a two-dimensional CMUT linear array for underwater applications. The operation frequencies for different medium have been calculated and simulated, which are 2.5 MHz in air and 0.7 MHz in water. The directivity analyses for the CMUT cell, subarray, and linear array have been provided. According to the product theorems, the directivity function of the complex array is obtained using a combination of the directivity functions of certain simple structures. Results show that the directivity of a CMUT cell is weak due to the small size, but the directivity of the designed linear array is very strong. Influential parameters of the linear array have been discussed, including the cell numbers, the adjacent distance, and the operation medium. In order to further suppress the side lobe interference and improve the resolution and the imaging quality of the imaging system, several weighting methods are used for optimization and comparison. Satisfactory side lobe suppression results are obtained, which can meet the actual requirements. Wen Zhang, Hui Zhang, Shijiu Jin, and Zhoumo Zeng Copyright © 2016 Wen Zhang et al. All rights reserved. Prediction Approach of Critical Node Based on Multiple Attribute Decision Making for Opportunistic Sensor Networks Tue, 12 Apr 2016 17:21:09 +0000 http://www.hindawi.com/journals/js/2016/8246030/ Predicting critical nodes of Opportunistic Sensor Network (OSN) can help us not only to improve network performance but also to decrease the cost in network maintenance. However, existing ways of predicting critical nodes in static network are not suitable for OSN. In this paper, the conceptions of critical nodes, region contribution, and cut-vertex in multiregion OSN are defined. We propose an approach to predict critical node for OSN, which is based on multiple attribute decision making (MADM). It takes RC to present the dependence of regions on Ferry nodes. TOPSIS algorithm is employed to find out Ferry node with maximum comprehensive contribution, which is a critical node. The experimental results show that, in different scenarios, this approach can predict the critical nodes of OSN better. Qifan Chen, Linlan Liu, Zhiyong Yang, and Kai Guo Copyright © 2016 Qifan Chen et al. All rights reserved. Indoor Operations by FMCW Millimeter Wave SAR Onboard Small UAS: A Simulation Approach Mon, 11 Apr 2016 12:58:09 +0000 http://www.hindawi.com/journals/js/2016/4968476/ A dedicated system simulator is presented in this paper for indoor operations onboard small Unmanned Aerial Systems (UAS) by a novel millimeter wave radar sensor. The sensor relies on the principle of Synthetic Aperture Radar (SAR) applied to a Frequency Modulated Continuous Wave (FMCW) radar system. Input to the simulator are both design parameters for Synthetic Aperture Radar (SAR), which should be able to cope with the stringent requirements set by indoor operations, and information about platform navigation and observed scene. The scene generation task is described in detail. This is based on models for point target response on either a completely absorbing background or fluctuating background and ray tracing (RT) techniques. Results obtained from scene processing are finally discussed, giving further insights on expected results from high-resolution observation of an assigned control volume by this novel SAR sensor. Antonio Fulvio Scannapieco, Alfredo Renga, and Antonio Moccia Copyright © 2016 Antonio Fulvio Scannapieco et al. All rights reserved. A Novel Improved Probability-Guided RANSAC Algorithm for Robot 3D Map Building Mon, 11 Apr 2016 11:13:02 +0000 http://www.hindawi.com/journals/js/2016/3243842/ This paper presents a novel improved RANSAC algorithm based on probability and DS evidence theory to deal with the robust pose estimation in robot 3D map building. In this proposed RANSAC algorithm, a parameter model is estimated by using a random sampling test set. Based on this estimated model, all points are tested to evaluate the fitness of current parameter model and their probabilities are updated by using a total probability formula during the iterations. The maximum size of inlier set containing the test point is taken into account to get a more reliable evaluation for test points by using DS evidence theory. Furthermore, the theories of forgetting are utilized to filter out the unstable inliers and improve the stability of the proposed algorithm. In order to boost a high performance, an inverse mapping sampling strategy is adopted based on the updated probabilities of points. Both the simulations and real experimental results demonstrate the feasibility and effectiveness of the proposed algorithm. Songmin Jia, Ke Wang, Xiuzhi Li, and Tao Xu Copyright © 2016 Songmin Jia et al. All rights reserved. Geometry Optimization Approaches of Inductively Coupled Printed Spiral Coils for Remote Powering of Implantable Biomedical Sensors Sun, 10 Apr 2016 13:16:20 +0000 http://www.hindawi.com/journals/js/2016/4869571/ Electronic biomedical implantable sensors need power to perform. Among the main reported approaches, inductive link is the most commonly used method for remote powering of such devices. Power efficiency is the most important characteristic to be considered when designing inductive links to transfer energy to implantable biomedical sensors. The maximum power efficiency is obtained for maximum coupling and quality factors of the coils and is generally limited as the coupling between the inductors is usually very small. This paper is dealing with geometry optimization of inductively coupled printed spiral coils for powering a given implantable sensor system. For this aim, Iterative Procedure (IP) and Genetic Algorithm (GA) analytic based optimization approaches are proposed. Both of these approaches implement simple mathematical models that approximate the coil parameters and the link efficiency values. Using numerical simulations based on Finite Element Method (FEM) and with experimental validation, the proposed analytic approaches are shown to have improved accurate performance results in comparison with the obtained performance of a reference design case. The analytical GA and IP optimization methods are also compared to a purely Finite Element Method based on numerical optimization approach (GA-FEM). Numerical and experimental validations confirmed the accuracy and the effectiveness of the analytical optimization approaches to design the optimal coil geometries for the best values of efficiency. Sondos Mehri, Ahmed Chiheb Ammari, Jaleleddine Ben Hadj Slama, and Hatem Rmili Copyright © 2016 Sondos Mehri et al. All rights reserved. Trust Dynamics in WSNs: An Evolutionary Game-Theoretic Approach Sun, 10 Apr 2016 13:16:03 +0000 http://www.hindawi.com/journals/js/2016/4254701/ A sensor node (SN) in Wireless Sensor Networks (WSNs) can decide whether to collaborate with others based on a trust management system (TMS) by making a trust decision. In this paper, we study the trust decision and its dynamics that play a key role to stabilize the whole network using evolutionary game theory. When SNs are making their decisions to select action Trust or Mistrust, a WSNs trust game is created to reflect their utilities. An incentive mechanism bound with one SN’s trust degree is incorporated into this trust game and effectively promotes SNs to select action Trust. The replicator dynamics of SNs’ trust evolution, illustrating the evolutionary process of SNs selecting their actions, are given. We then propose and prove the theorems indicating that evolutionarily stable strategies can be attained under different parameter values, which supply theoretical foundations to devise a TMS for WSNs. Moreover, we can find out the conditions that will lead SNs to choose action Trust as their final behavior. In this manner, we can assure WSNs’ security and stability by introducing a trust mechanism to satisfy these conditions. Experimental results have confirmed the proposed theorems and the effects of the incentive mechanism. Shigen Shen, Longjun Huang, En Fan, Keli Hu, Jianhua Liu, and Qiying Cao Copyright © 2016 Shigen Shen et al. All rights reserved. Hall Effect Devices with Three Terminals: Their Magnetic Sensitivity and Offset Cancellation Scheme Tue, 05 Apr 2016 09:04:45 +0000 http://www.hindawi.com/journals/js/2016/5625607/ This paper discusses properties of Hall effect sensors with only three terminals and compares them to conventional four-terminal devices. It covers both Horizontal and Vertical Hall effect devices. Their Hall-geometry factor is computed analytically. Several modes of operation are proposed and their signal-to-noise ratio is compared. A six-phase offset cancellation scheme is developed. All theoretical results are checked by measurements. The residual offset of Vertical Hall effect devices with three contacts is found to be smaller than the offset of conventional Vertical Hall effect devices with five contacts. Udo Ausserlechner Copyright © 2016 Udo Ausserlechner. All rights reserved. CRAM: A Conditioned Reflex Action Inspired Adaptive Model for Context Addition in Wireless Sensor Networks Sun, 03 Apr 2016 16:52:11 +0000 http://www.hindawi.com/journals/js/2016/6319830/ In Wireless Sensor Networks (WSNs), Context Awareness is typically realized through Context Aware Systems (CASs). Although almost each CAS follows sense-decide-adapt cycle, the notion of context is hardwired into the applications; that is, when an event is triggered, the sense-decide-actuate cycle runs and performs required actuation. In situations, for instance, whenever the same event is triggered, the cycle produces the same actuation through mechanical use of the same resources, posing the same processing and time. In this paper, we propose CRAM, a context added system in which actuations once performed by the system help it to internally evolve by serving as new contexts. As the system is exposed to more situations overtime, its context repository is enriched through such retrospective contexts, gradually letting it perform internal actuation through improved introspective contexts. This internal actuation leads the system towards the evolution of intelligent processing by reducing the independent function of decision in sense-decide-actuate cycle and merging it with new context. Finally, the system reaches a juncture where recurrence of each event proves to be a stimulus for the system to respond impulsively, through priming memory of introspective contexts, to achieve an imitation of learned reflex action resulting into reduced time and energy expenditure. Majid Hussain, Muhammad Farrukh Shafeeq, Sana Jabbar, Ali Hammad Akbar, and Shahzad Khalid Copyright © 2016 Majid Hussain et al. All rights reserved. Sensors for Coastal Monitoring Sun, 03 Apr 2016 08:23:47 +0000 http://www.hindawi.com/journals/js/2016/1720563/ Francesco Serafino, Jochen Horstmann, José Carlos Nieto Borge, Claudio Lugni, and Maurizio Brocchini Copyright © 2016 Francesco Serafino et al. All rights reserved. In2O3- and SnO2-Based Thin Film Ozone Sensors: Fundamentals Thu, 31 Mar 2016 07:39:35 +0000 http://www.hindawi.com/journals/js/2016/3816094/ The paper considers SnO2 and In2O3 thin films as materials for the design of solid-state conductometric ozone sensors in depth. In particular, the present review covers the analysis of the fundamentals of SnO2- and In2O3-based conductometric ozone sensor operation. The main focus is on the description of mechanisms of ozone interaction with metal oxides, the influence of air humidity on sensor response, and processes that control the kinetics of sensor response to ozone. G. Korotcenkov, V. Brinzari, and B. K. Cho Copyright © 2016 G. Korotcenkov et al. All rights reserved. Adjacent Infrared Multitarget Detection Using Robust Background Estimation Wed, 30 Mar 2016 11:38:13 +0000 http://www.hindawi.com/journals/js/2016/7279081/ Small target detection is very important for infrared search and track (IRST) problems. Grouped targets are difficult to detect using the conventional constant false alarm rate (CFAR) detection method. In this study, a novel multitarget detection method was developed to identify adjacent or closely spaced small infrared targets. The neighboring targets decrease the signal-to-clutter ratio in hysteresis threshold-based constant false alarm rate (H-CFAR) detection, which leads to poor detection performance in cluttered environments. The proposed adjacent target rejection-based robust background estimation can reduce the effects of the neighboring targets and enhance the small multitarget detection performance in infrared images by increasing the signal-to-clutter ratio. The experimental results of the synthetic and real adjacent target sequences showed that the proposed method produces an upgraded detection rate with the same false alarm rate compared to the recent target detection methods (H-CFAR, Top-hat, and TDLMS). Sungho Kim and Kyung-Tae Kim Copyright © 2016 Sungho Kim and Kyung-Tae Kim. All rights reserved. Hexanal Gas Detection Using Chitosan Biopolymer as Sensing Material at Room Temperature Mon, 28 Mar 2016 11:58:55 +0000 http://www.hindawi.com/journals/js/2016/8539169/ Hexanal was identified as one of the major volatile gases which are produced in degraded dairy products and wood industries. Therefore, preliminary study on hexanal gas detection with the laboratory scale was carried out in this paper. Electrical testing with chitosan as a sensing material to sense hexanal gas in low concentration was carried out at room temperature. Chitosan sensor was fabricated by using electrochemical deposition technique to form active sensing layer. The response of the chitosan film sensor (CFS) towards hexanal was tested via electrical testing by exposing different hexanal concentrations ranging between 20 ppm, 100 ppm, 200 ppm, and 300 ppm using air as a carrier gas. Sensing properties of the CFS toward hexanal exposure including responsibility, recovery, repeatability, stability, and selectively were studied. Overall, our result suggested that hexanal sensor based on chitosan was able to perform well at room temperature demonstrated by good response, good recovery, good repeatability, good stability, and good selectively. This simple and low cost sensor has high potential to be utilized in early quality degradation detection in dairy products and can be used to monitor the level of hexanal exposure in wood industries. Devi Shantini, Irwana Nainggolan, Tulus Ikhsan Nasution, Mohd Nazree Derman, Roshida Mustaffa, and Nur Zuraihan Abd Wahab Copyright © 2016 Devi Shantini et al. All rights reserved. Development of Ammonia Gas Sensor Using Optimized Organometallic Reagent Sun, 27 Mar 2016 11:26:30 +0000 http://www.hindawi.com/journals/js/2016/8425758/ Reliable, continuous, and spatially distributed monitoring of dangerous or irritating chemical substances belongs to standard functions of contemporary industrial and public security systems. Fiber-optic-based detection provides feasible platform to fulfill such aims. This paper deals with characterization of ammonia sensing elements based on multimode polysiloxane-clad silica-core optical fibers sensitized with 5-(4′-dioctylamino phenylimino) quinoline-8-1 cobalt bromide complex reagent immobilized into the cross-linked polymer matrix from a proper mixture of organic solvents and a radical scavenger contributing to the desired long-term stability of optical properties. The applied sensing mechanism combines optical detection principle with chemical reaction of the reagent and ammonia resulting in changes in the visible near-infrared optical absorption spectrum of the cladding layer, influencing via evanescent optical field interactions the spectral distribution of the guided light intensity. Reaction kinetics of short fiber sections exposed to ammonia/nitrogen mixture of various ammonia concentrations is tested and evaluated. The obtained sensitivity, limit of detection, and forward response time of the prepared sensors amount to  ppm−1, 31 ppm, and 25 s, respectively. The obtained results are promising for fabrication of distributed fiber-optic sensors applicable to detection and location of ammonia gas leaks in industrial as well as general public premises. J. Aubrecht and L. Kalvoda Copyright © 2016 J. Aubrecht and L. Kalvoda. All rights reserved.