Journal of Sensors http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. A Standalone Vision Sensing System for Pseudodynamic Testing of Tuned Liquid Column Dampers Sun, 22 May 2016 08:18:19 +0000 http://www.hindawi.com/journals/js/2016/8152651/ Experimental investigation of the tuned liquid column damper (TLCD) is a primal factory task prior to its installation at a site and is mainly undertaken by a pseudodynamic test. In this study, a noncontact standalone vision sensing system is developed to replace a series of the conventional sensors installed at the TLCD tested. The fast vision sensing system is based on binary pixel counting of the portion of images steamed in a pseudodynamic test and achieves near real-time measurements of wave height, lateral motion, and control force of the TLCD. The versatile measurements of the system are theoretically and experimentally evaluated through a wide range of lab scale dynamic tests. Kyung-Won Min, Seok-Jung Jang, and Junhee Kim Copyright © 2016 Kyung-Won Min et al. All rights reserved. Radar Emission Sources Identification Based on Hierarchical Agglomerative Clustering for Large Data Sets Thu, 19 May 2016 16:25:12 +0000 http://www.hindawi.com/journals/js/2016/1879327/ More advanced recognition methods, which may recognize particular copies of radars of the same type, are called identification. The identification process of radar devices is a more specialized task which requires methods based on the analysis of distinctive features. These features are distinguished from the signals coming from the identified devices. Such a process is called Specific Emitter Identification (SEI). The identification of radar emission sources with the use of classic techniques based on the statistical analysis of basic measurable parameters of a signal such as Radio Frequency, Amplitude, Pulse Width, or Pulse Repetition Interval is not sufficient for SEI problems. This paper presents the method of hierarchical data clustering which is used in the process of radar identification. The Hierarchical Agglomerative Clustering Algorithm (HACA) based on Generalized Agglomerative Scheme (GAS) implemented and used in the research method is parameterized; therefore, it is possible to compare the results. The results of clustering are presented in dendrograms in this paper. The received results of grouping and identification based on HACA are compared with other SEI methods in order to assess the degree of their usefulness and effectiveness for systems of ESM/ELINT class. Janusz Dudczyk Copyright © 2016 Janusz Dudczyk. All rights reserved. Graphene-Based FET Detector for E. coli K12 Real-Time Monitoring and Its Theoretical Analysis Wed, 18 May 2016 11:26:33 +0000 http://www.hindawi.com/journals/js/2016/4641398/ This paper presents a theoretical analysis for a graphene-based FET real-time detector of the target bacteria E. coli K12. The motivation for this study is to design a sensor device for detection of bacteria in food and water in order to guarantee food safety. Graphene is chosen as our material for sensor design, which has outstanding electrical, physical, and optical performance. In our sensor structure, graphene-based solution gate field effect transistor (FET) is the device model; fabrication and functionalization protocol are presented together in this paper. What is more, a real-time signal display system is the accompanied equipment for our designed biosensor device. In this system, the sensor bias current signal would change obviously when the target bacteria are attached to the sensor surface. And the bias current increases when the E. coli concentration increases. In the latter part, a theoretical interpretation of the sensor signal is to explain the bias current increasing after the E. coli K12 attachment. Jieyi Zhu, Fuzhou Niu, Changan Zhu, Jie Yang, and Ning Xi Copyright © 2016 Jieyi Zhu et al. All rights reserved. Information Security of PHY Layer in Wireless Networks Wed, 18 May 2016 08:29:35 +0000 http://www.hindawi.com/journals/js/2016/1230387/ Since the characteristics of wireless channel are open and broadcasting, wireless networks are very vulnerable to be attacked via eavesdropping, jamming, and interference. As traditional secure technologies are not suitable for PHY layer of wireless networks, physical-layer security issues become a focus of attention. In this paper, we firstly identify and summarize the threats and vulnerabilities in PHY layer of wireless networks. Then, we give a holistic overview of PHY layer secure schemes, which are divided into three categories: spatial domain-based, time domain-based, and frequency domain-based. Along the way, we analyze the pros and cons of current secure technologies in each category. In addition, we also conclude the techniques and methods used in these categories and point out the open research issues and directions in this area. Weidong Fang, Fengrong Li, Yanzan Sun, Lianhai Shan, Shanji Chen, Chao Chen, and Meiju Li Copyright © 2016 Weidong Fang et al. All rights reserved. Modeling and Finite Element Analysis Simulation of MEMS Based Acetone Vapor Sensor for Noninvasive Screening of Diabetes Wed, 18 May 2016 06:50:09 +0000 http://www.hindawi.com/journals/js/2016/9563938/ Diabetes is currently screened invasively by measuring glucose concentration in blood, which is inconvenient. This paper reports a study on modeling and simulation of a CMOS-MEMS sensor for noninvasive screening of diabetes via detection of acetone vapor in exhaled breath (EB). The sensor has two structures: movable (rotor) and fixed (stator) plates. The rotor plate is suspended on top of the stator by support of four flexible beams and maintaining certain selected initial gaps of 5, 6, 7, 8, 9, 10, or 11 μm to form actuation and sensing parallel plate capacitors. A chitosan polymer of varied thicknesses (1–20 μm) is deposited on the rotor plate and modeled as a sensing element for the acetone vapor. The minimum polymer coating thickness required to detect the critical concentration (1.8 ppm) of acetone vapor in the EB of diabetic subjects is found to be 4–7 μm, depending on the initial gap between the rotor and stator plates. However, to achieve sub-ppm detection limit to sense the acetone vapor concentration (0.4–1.1 ppm) in the EB of healthy people, up to 20 μm polymer thickness is coated. The mathematically modeled results were verified using the 2008 CoventorWare simulation software and a good agreement within a 5.3% error was found between the modeled and the simulated frequencies giving more confidence in the predicted results. John Ojur Dennis, Almur Abdelkreem Saeed Rabih, Mohd Haris Md Khir, Mawahib Gafare Abdalrahman Ahmed, and Abdelazez Yousif Ahmed Copyright © 2016 John Ojur Dennis et al. All rights reserved. Precession Azimuth Sensing with Low-Noise Molecular Electronics Angular Sensors Tue, 17 May 2016 14:05:42 +0000 http://www.hindawi.com/journals/js/2016/6148019/ This paper describes the use of MET-based low-noise angular motion sensors to precisely determine azimuth direction in a dynamic-scheme method of measuring the Earth’s rotational velocity vector. The scheme includes sensor installation on a rotating platform so that it could scan the space and seek for the position of the highest Earth’s rotation vector projection on its axis. This method is very efficient provided a low-noise sensor is used. A low-cost angular sensor based on MET (molecular electronic transduction) technology has been used. The sensors of this kind were originally developed for seismic activity monitoring and are well known for very good noise performance and high sensitivity. This approach, combined with the use of special signal processing algorithms, allowed reaching the accuracy of 0.2°, while the measurement time was less than 100 seconds. Dmitry L. Zaitsev, Vadim M. Agafonov, Egor V. Egorov, Alexander N. Antonov, and Vladimir G. Krishtop Copyright © 2016 Dmitry L. Zaitsev et al. All rights reserved. Optimization-Based Artificial Bee Colony Algorithm for Data Collection in Large-Scale Mobile Wireless Sensor Networks Tue, 17 May 2016 13:59:41 +0000 http://www.hindawi.com/journals/js/2016/7057490/ Data collection is a fundamental operation in various mobile wireless sensor networks (MWSN) applications. The energy of nodes around the Sink can be untimely depleted owing to the fact that sensor nodes must transmit vast amounts of data, readily forming a bottleneck in energy consumption; mobile wireless sensor networks have been designed to address this issue. In this study, we focused on a large-scale and intensive MWSN which allows a certain amount of data latency by investigating mobile Sink balance from three aspects: data collection maximization, mobile path length minimization, and network reliability optimization. We also derived a corresponding formula to represent the MWSN and proved that it represents an NP-hard problem. Traditional data collection methods only focus on increasing the amount data collection or reducing the overall network energy consumption, which is why we designed the proposed heuristic algorithm to jointly consider cluster head selection, the routing path from ordinary nodes to the cluster head node, and mobile Sink path planning optimization. The proposed data collection algorithm for mobile Sinks is, in effect, based on artificial bee colony. Simulation results show that, in comparison with other algorithms, the proposed algorithm can effectively reduce data transmission, save energy, improve network data collection efficiency and reliability, and extend the network lifetime. Yinggao Yue, Jianqing Li, Hehong Fan, and Qin Qin Copyright © 2016 Yinggao Yue et al. All rights reserved. A Stream Processing System for Multisource Heterogeneous Sensor Data Tue, 17 May 2016 13:48:31 +0000 http://www.hindawi.com/journals/js/2016/4287834/ With the rapid development of the Internet of Things (IoT), a variety of sensor data are generated around everyone’s life. New research perspective regarding the streaming sensor data processing of the IoT has been raised as a hot research topic that is precisely the theme of this paper. Our study serves to provide guidance regarding the practical aspects of the IoT. Such guidance is rarely mentioned in the current research in which the focus has been more on theory and less on issues describing how to set up a practical system. In our study, we employ numerous open source projects to establish a distributed real time system to process streaming data of the IoT. Two urgent issues have been solved in our study that are (1) multisource heterogeneous sensor data integration and (2) processing streaming sensor data in real time manner with low latency. Furthermore, we set up a real time system to process streaming heterogeneous sensor data from multiple sources with low latency. Our tests are performed using field test data derived from environmental monitoring sensor data collected from indoor environment for system validation. The results show that our proposed system is valid and efficient for multisource heterogeneous sensor data integration and streaming data processing in real time manner. Liang Hu, Rui Sun, Feng Wang, Xiuhong Fei, and Kuo Zhao Copyright © 2016 Liang Hu et al. All rights reserved. Acceleration Characteristics of a Rock Slide Using the Particle Image Velocimetry Technique Tue, 17 May 2016 13:43:42 +0000 http://www.hindawi.com/journals/js/2016/2650871/ The Particle Image Velocimetry (PIV) technique with high precision and spatial resolution is a suitable sensor for flow field experiments. In this paper, the PIV technology was used to monitor the development of a displacement field, velocity field and acceleration field of a rock slide. It was found that the peak acceleration of the sliding surface appeared earlier than the peak acceleration of the sliding body. The characteristics of the rock slide including the short failure time, high velocities, and large accelerations indicate that the sliding forces and energy release rate of the slope are high. The deformation field showed that the sliding body was sliding outwards along the sliding surface while the sliding bed moved in an opposite direction. Moving upwards at the top of the sliding bed can be one of the warning signs for rock slide failure. Guoqing Chen, Le Li, Cong Zhao, Runqiu Huang, and Fan Guo Copyright © 2016 Guoqing Chen et al. All rights reserved. Water Soluble Cationic Porphyrin Sensor for Detection of Hg2+, Pb2+, Cd2+, and Cu2+ Mon, 16 May 2016 14:22:20 +0000 http://www.hindawi.com/journals/js/2016/1905454/ Here we report the sensing properties of the aqueous solution of meso-tetra(N-methyl-4-pyridyl)porphine tetrachloride (1) for simultaneous detection of toxic metal ions by using UV-vis spectroscopy. Cationic porphyrin 1 displayed different electronic absorptions in UV-vis region upon interacting with Hg2+, Pb2+, Cd2+, and Cu2+ ions in neutral water solution at room temperature. Quite interestingly, the porphyrin 1 showed that it can function as a single optical chemical sensor and/or metal ion receptor capable of detecting two or more toxic metal ions, particularly Hg2+, Pb2+, and Cd2+ ions coexisting in a water sample. Porphyrin 1 in an aqueous solution provides a unique UV-vis sensing system for the determination of Cd2+ in the presence of larger metal ions such as Hg2+, or Pb2+. Finally, the examination of the sensing properties of 1 demonstrated that it can operate as a Cu2+ ion selective sensor via metal displacement from the 1-Hg2+, 1-Pb2+, and 1-Cd2+. Matibur Zamadar, Christopher Orr, and Miranda Uherek Copyright © 2016 Matibur Zamadar et al. All rights reserved. Hyperspectral Image Denoising with Composite Regularization Models Mon, 16 May 2016 08:59:42 +0000 http://www.hindawi.com/journals/js/2016/6586032/ Denoising is a fundamental task in hyperspectral image (HSI) processing that can improve the performance of classification, unmixing, and other subsequent applications. In an HSI, there is a large amount of local and global redundancy in its spatial domain that can be used to preserve the details and texture. In addition, the correlation of the spectral domain is another valuable property that can be utilized to obtain good results. Therefore, in this paper, we proposed a novel HSI denoising scheme that exploits composite spatial-spectral information using a nonlocal technique (NLT). First, a specific way to extract patches is employed to mine the spatial-spectral knowledge effectively. Next, a framework with composite regularization models is used to implement the denoising. A number of HSI data sets are used in our evaluation experiments and the results demonstrate that the proposed algorithm outperforms other state-of-the-art HSI denoising methods. Ao Li, Deyun Chen, Kezheng Lin, and Guanglu Sun Copyright © 2016 Ao Li et al. All rights reserved. A Mobile Sensing System for Urban Monitoring with Adaptive Resolution Sun, 15 May 2016 12:19:35 +0000 http://www.hindawi.com/journals/js/2016/7901245/ This paper develops a mobile sensing system, the first system used in adaptive resolution urban air quality monitoring. In this system, we employ several taxis as sensor carries to collect original data and collect a variety of datasets, including meteorological data, traffic status data, and geographical data in the city. This paper also presents a novel method AG-PCEM (Adaptive Grid-Probabilistic Concentration Estimation Method) to infer the concentration for undetected grids using dynamic adaptive grids. We gradually collect the measurements throughout a year using a prototype system in Xiasha District of Hangzhou City, China. Experimental data has verified that the proposed system can achieve good performance in terms of computational cost and accuracy. The computational cost of AG-PCEM is reduced by about 40.2% compared with a static grid method PCEM under the condition of reaching the close accuracy, and the accuracy of AG-PCEM is far superior as widely used artificial neural network (ANN) and Gaussian process (GP), enhanced by 38.8% and 14.6%, respectively. The system can be expanded to wide-range air quality monitor by adjusting the initial grid resolution, and our findings can tell citizens actual air quality and help official management find pollution sources. Hongjie Guo, Guojun Dai, Jin Fan, Yifan Wu, Fangyao Shen, and Yidan Hu Copyright © 2016 Hongjie Guo et al. All rights reserved. Bayesian Train Localization with Particle Filter, Loosely Coupled GNSS, IMU, and a Track Map Thu, 12 May 2016 11:48:23 +0000 http://www.hindawi.com/journals/js/2016/2672640/ Train localization is safety-critical and therefore the approach requires a continuous availability and a track-selective accuracy. A probabilistic approach is followed up in order to cope with multiple sensors, measurement errors, imprecise information, and hidden variables as the topological position within the track network. The nonlinear estimation of the train localization posterior is addressed with a novel Rao-Blackwellized particle filter (RBPF) approach. There, embedded Kalman filters estimate certain linear state variables while the particle distribution can cope with the nonlinear cases of parallel tracks and switch scenarios. The train localization algorithm is further based on a track map and measurements from a Global Navigation Satellite System (GNSS) receiver and an inertial measurement unit (IMU). The GNSS integration is loosely coupled and the IMU integration is achieved without the common strapdown approach and suitable for low-cost IMUs. The implementation is evaluated with real measurements from a regional train at regular passenger service over 230 km of tracks with 107 split switches and parallel track scenarios of 58.5 km. The approach is analyzed with labeled data by means of ground truth of the traveled switch way. Track selectivity results reach 99.3% over parallel track scenarios and 97.2% of correctly resolved switch ways. Oliver Heirich Copyright © 2016 Oliver Heirich. All rights reserved. A Novel Seam Finding Method Using Downscaling and Cost for Image Stitching Tue, 10 May 2016 12:06:02 +0000 http://www.hindawi.com/journals/js/2016/5258473/ Seaming finding is an important step for creating panorama images because it smoothes away differences observed at boundaries between stitched images. We propose an improved seam finding method in which we define a cost function to measure the discrepancies that boundary pixels cause. We are also able to improve computing complexity by avoiding finding a seam over the whole area of overlapped region. Instead, we use a downscaled version of overlapped area to approximate a seam and then interpolate the seam to the original region. From experiments to generate panorama images, we compare our method with three other existing seam finding algorithms and observe that our method is able to produce better quality panorama image than the existing methods, while the processing time is comparable to those of the others. Jinwook Jeong and Kyungkoo Jun Copyright © 2016 Jinwook Jeong and Kyungkoo Jun. All rights reserved. Remote Sensing of Grassland Biophysical Parameters in the Context of the Sentinel-2 Satellite Mission Mon, 09 May 2016 14:20:15 +0000 http://www.hindawi.com/journals/js/2016/4612809/ This study investigates the potential of the Sentinel-2 satellite for monitoring the seasonal changes in grassland total canopy chlorophyll content (CCC), fraction of photosynthetically active radiation absorbed by the vegetation canopy (FAPAR), and fraction of photosynthetically active radiation absorbed only by its photosynthesizing components (GFAPAR). Reflectance observations were collected on a continuous basis during growing seasons by means of a newly developed ASD-WhiteRef system. Two models using Sentinel-2 simulated data (linear regression-vegetation indices (VIs) approach and multiple regression (MR) reflectance approach) were tested to estimate vegetation biophysical parameters. To assess whether the use of full solar spectrum reflectance data is able to provide an added value in CCC and GFAPAR estimation accuracy, a third model based on partial least squares regression (PLSR) and the ASD-WhiteRef reflectance data was tested. The results showed that FAPAR remained quite stable during the reproduction and senescence stages, and no significant relationships between FAPAR and VIs were found. On the other hand, GFAPAR showed clearer seasonal trends. The comparison of the three models revealed no significant differences in the accuracies of CCC and GFAPAR predictions and demonstrated a strong contribution of SWIR bands to the explained variability of investigated parameters. The promising results highlight the potential of the Sentinel-2 satellite for retrieving biophysical parameters from space. Karolina Sakowska, Radoslaw Juszczak, and Damiano Gianelle Copyright © 2016 Karolina Sakowska et al. All rights reserved. A Novel Encryption Algorithm Based on DWT and Multichaos Mapping Mon, 09 May 2016 12:34:28 +0000 http://www.hindawi.com/journals/js/2016/2646205/ Encryption of a digital image is very important especially in applications of body area networks (BANs) since the image may include a number of privacy. Past encryption methods have disadvantages of the small key space and low ability of resistance to attack. In this paper, we propose a new encryption algorithm based on discrete wavelet transform (DWT) and multichaos which has characteristics of the deterministic, pseudorandomness, and sensitivity of initial values. The image is first decomposed and spatial reconstructed by two-dimensional DWT and then is performed by multichaos matrices for space encryption. The experimental results indicate that the proposed algorithm has a large key space, high key sensitivity, and excellent ability of resistance to attack. Wei Wang, Haiyan Tan, Yu Pang, Zhangyong Li, Peng Ran, and Jun Wu Copyright © 2016 Wei Wang et al. All rights reserved. Context-Aware Mobile Sensors for Sensing Discrete Events in Smart Environment Mon, 09 May 2016 12:10:04 +0000 http://www.hindawi.com/journals/js/2016/7283831/ Over the last few decades, several advancements in the field of smart environment gained importance, so the experts can analyze ideas for smart building based on embedded systems to minimize the expense and energy conservation. Therefore, propelling the concept of smart home toward smart building, several challenges of power, communication, and sensors’ connectivity can be seen. Such challenges distort the interconnectivity between different technologies, such as Bluetooth and ZigBee, making it possible to provide the continuous connectivity among different objects such as sensors, actuators, home appliances, and cell phones. Therefore, this paper presents the concept of smart building based on embedded systems that enhance low power mobile sensors for sensing discrete events in embedded systems. The proposed scheme comprises system architecture that welcomes all the mobile sensors to communicate with each other using a single platform service. The proposed system enhances the concept of smart building in three stages (i.e., visualization, data analysis, and application). For low power mobile sensors, we propose a communication model, which provides a common medium for communication. Finally, the results show that the proposed system architecture efficiently processes, analyzes, and integrates different datasets efficiently and triggers actions to provide safety measurements for the elderly, patients, and others. Awais Ahmad, M. Mazhar Rathore, Anand Paul, Won-Hwa Hong, and HyunCheol Seo Copyright © 2016 Awais Ahmad et al. All rights reserved. Noise Estimation and Suppression Using Nonlinear Function with A Priori Speech Absence Probability in Speech Enhancement Mon, 09 May 2016 11:44:12 +0000 http://www.hindawi.com/journals/js/2016/5352437/ This paper proposes a noise-biased compensation of minimum statistics (MS) method using a nonlinear function and a priori speech absence probability (SAP) for speech enhancement in highly nonstationary noisy environments. The MS method is a well-known technique for noise power estimation in nonstationary noisy environments; however, it tends to bias noise estimation below that of the true noise level. The proposed method is combined with an adaptive parameter based on a sigmoid function and a priori SAP for residual noise reduction. Additionally, our method uses an autoparameter to control the trade-off between speech distortion and residual noise. We evaluate the estimation of noise power in highly nonstationary and varying noise environments. The improvement can be confirmed in terms of signal-to-noise ratio (SNR) and the Itakura-Saito Distortion Measure (ISDM). Soojeong Lee and Gangseong Lee Copyright © 2016 Soojeong Lee and Gangseong Lee. All rights reserved. Nanogravimetric and Optical Characterizations of Thrombin Interaction with a Self-Assembled Thiolated Aptamer Mon, 09 May 2016 11:21:06 +0000 http://www.hindawi.com/journals/js/2016/3561863/ Efficient biorecognition of thrombin (TB), a serine protease with crucial role in physiological and pathological blood coagulation, is a hot topic in medical diagnostics. In this work, we investigate the ability of synthetic thrombin aptamer (TBA), immobilized on a gold substrate, to bind thrombin by two different label-free techniques: the quartz crystal microbalance (QCM) and the spectroscopic ellipsometry (SE). By QCM characterization in the range from 20 to 110 nM, we demonstrate high specificity of TBA-TB interaction and determine affinity constant () of  nM, system sensitivity of  Hz nM−1, and limit of detection (LOD) of  pM. The interaction between TBA and TB is also investigated by SE, an all-optical method, by quantifying the thickness increase of the TBA film assembled on gold substrate. AFM characterization of TBA and TB molecules deposited on flat silicon surface is also supplied. Jane Politi, Ilaria Rea, Fabrizia Nici, Principia Dardano, Monica Terracciano, Giorgia Oliviero, Nicola Borbone, Gennaro Piccialli, and Luca De Stefano Copyright © 2016 Jane Politi et al. All rights reserved. Sensor Module Based on the Wireless Sensor Network for the Dynamic Stress on the Flexible Object with Large Deformation Mon, 09 May 2016 10:52:34 +0000 http://www.hindawi.com/journals/js/2016/1368309/ When we are measuring the dynamic stress on flexible objects with large deformation, for example, the parachute, the morphologic structure of the tested objects changes rapidly and sharply, and the measurement is conducted in a poor and variable environment. Traditional measuring methods cannot ensure credibility, repeatability, and high precision of the test. This paper introduces stress sensor module based on the wireless sensor network for the flexible objects with large deformation. In this paper, the wireless sensor network works as the signal transmitting carrier and the Ω sensor is improved. In addition, the paper further studies the effect of module deployment on the flexible objects with large deformation and the effect of experiment environment on the sensor test. Finally, the compensation method is proposed and measurement reliability is improved. The performance experiments of the sensor verify the availability and repeatability of the dynamic sensor module. The drop experiment of the small parachute and the wind tunnel experiment prove that the sensor module can effectively measure the stress on the flexible object with large deformation and the results accord with the parachute canopy stress rule. Jinhui Zhao, Yi Zhuang, Jingjing Gu, Yan Xu, and Jian Sun Copyright © 2016 Jinhui Zhao et al. All rights reserved. Citizen Sensing for Improved Urban Environmental Monitoring Thu, 05 May 2016 16:27:22 +0000 http://www.hindawi.com/journals/js/2016/5656245/ Citizen science is increasingly being used in diverse research domains. With the emergence and rapid development of sensor technologies, citizens potentially have more powerful tools to collect data and generate information to understand their living environment. Although sensor technologies are developing fast, citizen sensing has not been widely implemented yet and published studies are only a few. In this paper, we analyse the practical experiences from an implementation of citizen sensing for urban environment monitoring. A bottom-up model in which citizens develop and use sensors for environmental monitoring is described and assessed. The paper focuses on a case study of Amsterdam Smart Citizens Lab using NO2 sensors for air quality monitoring. We found that the bottom-up citizen sensing is still challenging but can be successful with open cooperation and effective use of online and offline facilities. Based on the assessment, suggestions are proposed for further implementations and research. Qijun Jiang, Frank Kresin, Arnold K. Bregt, Lammert Kooistra, Emma Pareschi, Edith van Putten, Hester Volten, and Joost Wesseling Copyright © 2016 Qijun Jiang et al. 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.