Journal of Sensors http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Investigation on a Novel Capacitive Electrode for Geophysical Surveys Wed, 29 Jun 2016 12:51:04 +0000 http://www.hindawi.com/journals/js/2016/4209850/ Nonpolarizable electrodes are applied widely in the electric field measurement for geophysical surveys. However, there are two major problems: (1) systematic errors caused by poor electrical contact in the high resistive terrains and (2) environmental damage associated with using nonpolarizable electrodes. A new alternative structure of capacitive electrode, which is capable of sensing surface potential through weak capacitive coupling, is presented to solve the above problems. A technique is introduced to neutralize distributed capacitance and input capacitance of the detection circuit. With the capacitance neutralization technique, the transmission coefficient of capacitive electrode remains stable when environmental conditions change. The simulation and field test results indicate that the new capacitive electrode has an operating bandwidth range from 0.1 Hz to 1 kHz. The capacitive electrodes have a good prospect of the applications in geophysical prospecting, especially in resistive terrains. Zhiyu Wang, Shun Wang, Guangyou Fang, and Qunying Zhang Copyright © 2016 Zhiyu Wang et al. All rights reserved. An Algorithmic Approach to Wireless Sensor Networks Localization Using Rigid Graphs Wed, 29 Jun 2016 11:11:46 +0000 http://www.hindawi.com/journals/js/2016/3986321/ In this work estimating the position coordinates of Wireless Sensor Network nodes using the concept of rigid graphs is carried out in detail. The range based localization approaches use the distance information measured by the RSSI, which is prone to noise, due to effects of path loss, shadowing, and so forth. In this work, both the distance and the bearing information are used for localization using the trilateration technique. Rigid graph theory is employed to analyze the localizability, that is, whether the nodes of the WSN are uniquely localized. The WSN graph is divided into rigid patches by varying appropriately the communication power range of the WSN nodes and then localizing the patches by trilateration. The main advantage of localizing the network using rigid graph approach is that it overcomes the effect of noisy perturbed distance. Our approach gives a better performance compared to robust quads in terms of percentage of localizable nodes and computational complexity. Shamantha Rai B and Shirshu Varma Copyright © 2016 Shamantha Rai B and Shirshu Varma. All rights reserved. Handwriting Recognition in Free Space Using WIMU-Based Hand Motion Analysis Wed, 29 Jun 2016 11:05:14 +0000 http://www.hindawi.com/journals/js/2016/3692876/ We present a wireless-inertial-measurement-unit- (WIMU-) based hand motion analysis technique for handwriting recognition in three-dimensional (3D) space. The proposed handwriting recognition system is not bounded by any limitations or constraints; users have the freedom and flexibility to write characters in free space. It uses hand motion analysis to segment hand motion data from a WIMU device that incorporates magnetic, angular rate, and gravity sensors (MARG) and a sensor fusion algorithm to automatically distinguish segments that represent handwriting from nonhandwriting data in continuous hand motion data. Dynamic time warping (DTW) recognition algorithm is used to recognize handwriting in real-time. We demonstrate that a user can freely write in air using an intuitive WIMU as an input and hand motion analysis device to recognize the handwriting in 3D space. The experimental results for recognizing handwriting in free space show that the proposed method is effective and efficient for other natural interaction techniques, such as in computer games and real-time hand gesture recognition applications. Shashidhar Patil, Dubeom Kim, Seongsill Park, and Youngho Chai Copyright © 2016 Shashidhar Patil et al. All rights reserved. Computer Vision-Based Portable System for Nitroaromatics Discrimination Wed, 29 Jun 2016 09:49:31 +0000 http://www.hindawi.com/journals/js/2016/7087013/ A computer vision-based portable measurement system is presented in this report. The system is based on a compact reader unit composed of a microcamera and a Raspberry Pi board as control unit. This reader can acquire and process images of a sensor array formed by four nonselective sensing chemistries. Processing these array images it is possible to identify and quantify eight different nitroaromatic compounds (both explosives and related compounds) by using chromatic coordinates of a color space. The system is also capable of sending the obtained information after the processing by a WiFi link to a smartphone in order to present the analysis result to the final user. The identification and quantification algorithm programmed in the Raspberry board is easy and quick enough to allow real time analysis. Nitroaromatic compounds analyzed in the range of mg/L were picric acid, 2,4-dinitrotoluene (2,4-DNT), 1,3-dinitrobenzene (1,3-DNB), 3,5-dinitrobenzonitrile (3,5-DNBN), 2-chloro-3,5-dinitrobenzotrifluoride (2-C-3,5-DNBF), 1,3,5-trinitrobenzene (TNB), 2,4,6-trinitrotoluene (TNT), and tetryl (TT). Nuria López-Ruiz, Miguel M. Erenas, Ignacio de Orbe-Payá, Luis F. Capitán-Vallvey, Alberto J. Palma, and Antonio Martínez-Olmos Copyright © 2016 Nuria López-Ruiz et al. All rights reserved. Test Verification and Application of a Longitudinal Temperature Force Testing Method for Long Seamless Rails Using FBG Strain Sensor Wed, 29 Jun 2016 09:21:41 +0000 http://www.hindawi.com/journals/js/2016/3917604/ In order to evaluate the health status of continuous welded rail accurately, a deduction on the FBG sensing principle has been made with regard to the temperature variation of test specimens under different constraint conditions. A long seamless rail testing solution and its on-site application are designed based on this deduction. According to the verification experiments of sensing principle inside, the effect of the reference temperature on the FBG temperature and strain sensitivity coefficient within −30°C~30°C is not higher than 0.05%; the maximum relative error of single point between the tested and theoretical results of test specimen under constrained condition is 3.2%; and the maximum relative error of slopes of fitted straight lines based on the tested and theoretical results within the entire test temperature range is 2.3%, verifying the deduced FBG sensing principle with regard to the test specimen under constrained condition. The maximum error of the longitudinal temperature force between the on-site tested results and calculated results in long seamless rails is only 6.1 kN, the corresponding rail temperature variation is 0.3°C, and the accumulated error is controllable within 5%. Ping Wang, Kaize Xie, Rong Chen, Liyang Shao, Lianshan Yan, Hao Liu, and Meng Zhang Copyright © 2016 Ping Wang et al. All rights reserved. RESH: A Secure Authentication Algorithm Based on Regeneration Encoding Self-Healing Technology in WSN Wed, 29 Jun 2016 09:21:34 +0000 http://www.hindawi.com/journals/js/2016/2098680/ In the real application environment of wireless sensor networks (WSNs), the uncertain factor of data storage makes the authentication information be easily forged and destroyed by illegal attackers. As a result, it is hard for secure managers to conduct forensics on transmitted information in WSN. This work considers the regeneration encoding self-healing and secret sharing techniques and proposes an effective scheme to authenticate data in WSN. The data is encoded by regeneration codes and then distributed to other redundant nodes in the form of fragments. When the network is attacked, the scheme has the ability against tampering attack or collusion attack. Furthermore, the damaged fragments can be restored as well. Parts of fragments, encoded by regeneration code, are required for secure authentication of the original distributed data. Experimental results show that the proposed scheme reduces hardware communication overhead by five percent in comparison. Additionally, the performance of local recovery achieves ninety percent. Wei Liang, Zhiqiang Ruan, Yuntao Wang, and Xiaoyan Chen Copyright © 2016 Wei Liang et al. All rights reserved. Numerical Study on Mass Sensitivity of Magnetoelastic Biosensors with Concentrated Mass Load under Different Resonance Modes Tue, 28 Jun 2016 06:18:56 +0000 http://www.hindawi.com/journals/js/2016/8341656/ Magnetoelastic biosensors are an important type of resonant mode based mass-sensing device, for which mass sensitivity is a critical parameter to evaluate their performance. In this work, the effect of concentrated mass position on mass sensitivity () of a magnetoelastic sensor under different resonance modes was theoretically studied. The effect of magnitude of loading mass on mass sensitivity for the first resonance mode was also studied. The results indicated that mass sensitivity as the function of loading position for all resonance modes was consistent with the law of function . By comparing the mass sensitivity for the sensor attached with concentrated mass and uniform mass, it was found that mass sensitivity was linearly proportional to the sum of the squares of the displacement of each loading point. For the first resonance mode, when the loading position satisfied or , mass sensitivity decreased with loading mass increasing. The opposite trend was observed when or . When the concentrated mass was loaded at the nodal point (i.e., ), mass sensitivity was always zero no matter how the loading mass changed. Kewei Zhang and Yuesheng Chai Copyright © 2016 Kewei Zhang and Yuesheng Chai. All rights reserved. Study of Wireless Authentication Center with Mixed Encryption in WSN Mon, 27 Jun 2016 14:27:04 +0000 http://www.hindawi.com/journals/js/2016/9297562/ WSN (wireless sensor network) has been used in a wide range of applications nowadays. Sensor networks may often relay critical data; thus, security must be a high priority. However, due to their limited computational, energy, and storage resources, sensor nodes are vulnerable to attack. So how to protect sensor nodes from attacks without raising computational capability and energy consumption is a worthwhile issue. A WAC (wireless authentication center) with mixed encryption named “MEWAC” is proposed. MEWAC is based on MCU (Microcontroller Unit) and WiFi (Wireless Fidelity) module and uses RSA, AES (Advanced Encryption Standard), and SHA-1 (Secure Hash Algorithm 1) to provide high performance authentication and data encryption services for sensor nodes. The experimental results show that MEWAC has the advantages of low cost, low power consumption, good performance, and stability; moreover, the authentication protocol improves the security of WSN and reduces the overhead in node authentication. Yiqin Lu, Jing Zhai, Ronghuan Zhu, and Jiancheng Qin Copyright © 2016 Yiqin Lu et al. All rights reserved. Multilevel Modeling of Distributed Denial of Service Attacks in Wireless Sensor Networks Mon, 27 Jun 2016 14:19:31 +0000 http://www.hindawi.com/journals/js/2016/5017248/ The growing popularity of wireless sensor networks increases the risk of security attacks. One of the most common and dangerous types of attack that takes place these days in any electronic society is a distributed denial of service attack. Due to the resource constraint nature of mobile sensors, DDoS attacks have become a major threat to its stability. In this paper, we established a model of a structural health monitoring network, being disturbed by one of the most common types of DDoS attacks, the flooding attack. Through a set of simulations, we explore the scope of flood-based DDoS attack problem, assessing the performance and the lifetime of the network under the attack condition. To conduct our research, we utilized the Quality of Protection Modeling Language. With the proposed approach, it was possible to examine numerous network configurations, parameters, attack options, and scenarios. The results of the carefully performed multilevel analysis allowed us to identify a new kind of DDoS attack, the delayed distributed denial of service, by the authors, referred to as DDDoS attack. Multilevel approach to DDoS attack analysis confirmed that, examining endangered environments, it is significant to take into account many characteristics at once, just to not overlook any important aspect. Katarzyna Mazur, Bogdan Ksiezopolski, and Radoslaw Nielek Copyright © 2016 Katarzyna Mazur et al. All rights reserved. Enhancing Energy Efficiency of Wireless Sensor Network through the Design of Energy Efficient Routing Protocol Sun, 26 Jun 2016 09:04:40 +0000 http://www.hindawi.com/journals/js/2016/9278701/ Wireless Sensor Network (WSN) is known to be a highly resource constrained class of network where energy consumption is one of the prime concerns. In this research, a cross layer design methodology was adopted to design an energy efficient routing protocol entitled “Position Responsive Routing Protocol” (PRRP). PRRP is designed to minimize energy consumed in each node by (1) reducing the amount of time in which a sensor node is in an idle listening state and (2) reducing the average communication distance over the network. The performance of the proposed PRRP was critically evaluated in the context of network lifetime, throughput, and energy consumption of the network per individual basis and per data packet basis. The research results were analyzed and benchmarked against the well-known LEACH and CELRP protocols. The outcomes show a significant improvement in the WSN in terms of energy efficiency and the overall performance of WSN. Noor Zaman, Low Tang Jung, and Muhammad Mehboob Yasin Copyright © 2016 Noor Zaman et al. All rights reserved. Research on the Calibration Method of Micro Inertial Measurement Unit for Engineering Application Thu, 23 Jun 2016 14:58:40 +0000 http://www.hindawi.com/journals/js/2016/9108197/ With rapid development of micro fabrication technology, the production level of micro inertial devices has increased, which promoted the performance improvement of Micro Inertial Measurement Unit (MIMU). Measurement precision of MIMU is one of the most significant indexes, especially for the application of the guided spinning projectiles. In order to improve the measurement precision of MIMU, this paper presents a novel calibration method. The calibration model is established and the derivation for parameters estimation has been introduced. By the multirate tests and multiposition tests, all the parameters in the calibration model can be well estimated. Verification experiment shows that the proposed method has the same compensation effect as the traditional method, but it can alleviate the computing burden for the system. Thus the proposed method will have a wide application prospect for the future engineering calibration. Yun Xu, Yu Wang, Yan Su, and Xinhua Zhu Copyright © 2016 Yun Xu et al. All rights reserved. Exploiting Performance of Different Low-Cost Sensors for Small Amplitude Oscillatory Motion Monitoring: Preliminary Comparisons in View of Possible Integration Tue, 21 Jun 2016 15:06:05 +0000 http://www.hindawi.com/journals/js/2016/7490870/ We address the problem of low amplitude oscillatory motion detection through different low-cost sensors: a LIS3LV02DQ MEMS accelerometer, a Microsoft Kinect v2 range camera, and a uBlox 6 GPS receiver. Several tests were performed using a one-direction vibrating table with different oscillation frequencies (in the range 1.5–3 Hz) and small challenging amplitudes (0.02 m and 0.03 m). A Mikrotron EoSens high-resolution camera was used to give reference data. A dedicated software tool was developed to retrieve Kinect v2 results. The capabilities of the VADASE algorithm were employed to process uBlox 6 GPS receiver observations. In the investigated time interval (in the order of tens of seconds) the results obtained indicate that displacements were detected with the resolution of fractions of millimeters with MEMS accelerometer and Kinect v2 and few millimeters with uBlox 6. MEMS accelerometer displays the lowest noise but a significant bias, whereas Kinect v2 and uBlox 6 appear more stable. The results suggest the possibility of sensor integration both for indoor (MEMS accelerometer + Kinect v2) and for outdoor (MEMS accelerometer + uBlox 6) applications and seem promising for structural monitoring applications. Elisa Benedetti, Roberta Ravanelli, Monica Moroni, Andrea Nascetti, and Mattia Crespi Copyright © 2016 Elisa Benedetti et al. All rights reserved. Design and Fabrication of Air-Based 1-3 Piezoelectric Composite Transducer for Air-Coupled Ultrasonic Applications Mon, 20 Jun 2016 15:07:22 +0000 http://www.hindawi.com/journals/js/2016/4982616/ The air-based 1-3 piezoelectric composite transducers are designed and fabricated in order to solve the acoustic impedance matching problem. Firstly, a finite element model using honeycomb structure as the piezoelectric composite matrix is built to reduce the acoustic impedance of the sensitive element. Three important factors, volume fraction of piezoelectric materials , the thickness , and the size of the square cross section of piezoelectric column, are examined and verified in simulation. Then, according to the result of simulation, the piezoelectric composites and the air-coupled transducers are fabricated. The honeycomb structures of resin are produced by the method of 3D printing technology, with the volume fraction of air being 30%. The impedance characteristics and the excitation/reception performance of the air-coupled transducers are measured and optimized. Meanwhile, a scanning experiment is carried out to demonstrate the crack detection process in monocrystalline silicon. mode of Lamb waves is excited and collected. The location and size of the defect will be determined by calculating the correlation coefficients of the received signals and reference signals. Finally, a 15 mm × 0.5 mm × 0.5 mm scratch is clearly distinguished. Cunfu He, Yaoyao Wang, Yan Lu, Yuepeng Liu, and Bin Wu Copyright © 2016 Cunfu He et al. All rights reserved. Hybrid Wireless Sensor Network Coverage Holes Restoring Algorithm Mon, 20 Jun 2016 10:48:18 +0000 http://www.hindawi.com/journals/js/2016/8064509/ Aiming at the perception hole caused by the necessary movement or failure of nodes in the wireless sensor actuator network, this paper proposed a kind of coverage restoring scheme based on hybrid particle swarm optimization algorithm. The scheme first introduced network coverage based on grids, transformed the coverage restoring problem into unconstrained optimization problem taking the network coverage as the optimization target, and then solved the optimization problem in the use of the hybrid particle swarm optimization algorithm with the idea of simulated annealing. Simulation results show that the probabilistic jumping property of simulated annealing algorithm could make up for the defect that particle swarm optimization algorithm is easy to fall into premature convergence, and the hybrid algorithm can effectively solve the coverage restoring problem. Liu Zhouzhou and Yanhong She Copyright © 2016 Liu Zhouzhou and Yanhong She. All rights reserved. Indoor Positioning System Using Depth Maps and Wireless Networks Wed, 15 Jun 2016 08:55:41 +0000 http://www.hindawi.com/journals/js/2016/2107872/ This work presents a new Indoor Positioning System (IPS) based on the combination of WiFi Positioning System (WPS) and depth maps, for estimating the location of people. The combination of both technologies improves the efficiency of existing methods, based uniquely on wireless positioning techniques. While other positioning systems force users to wear special devices, the system proposed in this paper just requires the use of smartphones, besides the installation of RGB-D sensors in the sensing area. Furthermore, the system is not intrusive, being not necessary to know people’s identity. The paper exposes the method developed for putting together and exploiting both types of sensory information with positioning purposes: the measurements of the level of the signal received from different access points (APs) of the wireless network and the depth maps provided by the RGB-D cameras. The obtained results show a significant improvement in terms of positioning with respect to common WiFi-based systems. Jaime Duque Domingo, Carlos Cerrada, Enrique Valero, and J. A. Cerrada Copyright © 2016 Jaime Duque Domingo et al. All rights reserved. Pipeline Bending Strain Measurement and Compensation Technology Based on Wavelet Neural Network Tue, 14 Jun 2016 12:16:40 +0000 http://www.hindawi.com/journals/js/2016/8363242/ The bending strain of long distance oil and gas pipelines may lead to instability of the pipeline and failure of materials, which seriously deteriorates the transportation security of oil and gas. To locate the position of the bending strain for maintenance, an Inertial Measurement Unit (IMU) is usually adopted in a Pipeline Inspection Gauge (PIG). The attitude data of the IMU is usually acquired to calculate the bending strain in the pipe. However, because of the vibrations in the pipeline and other system noises, the resulting bending strain calculations may be incorrect. To improve the measurement precision, a method, based on wavelet neural network, was proposed. To test the proposed method experimentally, a PIG with the proposed method is used to detect a straight pipeline. It can be obtained that the proposed method has a better repeatability and convergence than the original method. Furthermore, the new method is more accurate than the original method and the accuracy of bending strain is raised by about 23% compared to original method. This paper provides a novel method for precisely inspecting bending strain of long distance oil and gas pipelines and lays a foundation for improving the precision of inspection of bending strain of long distance oil and gas pipelines. Rui Li, Maolin Cai, Yan Shi, Qingshan Feng, Shucong Liu, and Xiaoming Zhao Copyright © 2016 Rui Li et al. All rights reserved. An Energy-Efficient Secure Scheme in Wireless Sensor Networks Tue, 14 Jun 2016 06:34:40 +0000 http://www.hindawi.com/journals/js/2016/1321079/ We propose an energy-efficient security scheme in wireless sensor networks. The proposed scheme converts sensing data using TinyMD5, which is a variation of MD5, a one-way hash function, and can solve the collision problem of hash value that occurs when MD5 is modified. In addition, it strengthens security capabilities by transmitting data through multiple paths after conversion with TinyMD5 and divides the data to make decryption of the original data difficult. To show the superiority of the proposed algorithm, we compare it with the existing schemes through simulations. The performance evaluation results show that the proposed scheme maintains security better than the existing scheme, improving the communication cost and the network lifetime. Kyoungsoo Bok, Yunjeong Lee, Junho Park, and Jaesoo Yoo Copyright © 2016 Kyoungsoo Bok et al. All rights reserved. ECG Sensor Verification System with Mean-Interval Algorithm for Handling Sport Issue Sun, 12 Jun 2016 12:23:38 +0000 http://www.hindawi.com/journals/js/2016/1814264/ With the development of biometric verification, we proposed a new algorithm and personal mobile sensor card system for ECG verification. The proposed new mean-interval approach can identify the user quickly with high accuracy and consumes a small amount of flash memory in the microprocessor. The new framework of the mobile card system makes ECG verification become a feasible application to overcome the issues of a centralized database. For a fair and comprehensive evaluation, the experimental results have been tested on public MIT-BIH ECG databases and our circuit system; they confirm that the proposed scheme is able to provide excellent accuracy and low complexity. Moreover, we also proposed a multiple-state solution to handle the heat rate changes of sports problem. It should be the first to address the issue of sports in ECG verification. Kuo-Kun Tseng, Fufu Zeng, W. H. Ip, and C. H. Wu Copyright © 2016 Kuo-Kun Tseng et al. All rights reserved. An Optimized Method Based on Digitalized Lissajous Curve to Determine Lifetime of Luminescent Materials on Optical Fiber Sensors Sun, 12 Jun 2016 07:42:44 +0000 http://www.hindawi.com/journals/js/2016/6019439/ A method is proposed to determine lifetime of luminescent emissions based on the phase shift measurement employing the digitalized Lissajous representation: this diagram has been typically used with analogical algorithms, whereas the proposed method is performed in digital domain, showing an improved accuracy and repeatability. The procedure is studied and tested with two different oxygen sensors that show different sensitivities and signal levels in order to confirm the no influence of the signals intensity on the calibration process. The computational cost of the proposed method is low, which makes it possible to monitor in real time luminescence sensors based on reversible quenching with a potential low cost system based on a digital signal processor (DSP). Adrián Ridruejo, Nerea De Acha, César Elosúa, Ignacio R. Matías, and Francisco J. Arregui Copyright © 2016 Adrián Ridruejo et al. All rights reserved. Cost-Effective Brillouin Optical Time-Domain Analysis Sensor Using a Single Optical Source and Passive Optical Filtering Thu, 09 Jun 2016 08:48:09 +0000 http://www.hindawi.com/journals/js/2016/8243269/ We present a simplified configuration for distributed Brillouin optical time-domain analysis sensors that aims to reduce the cost of the sensor by reducing the number of components required for the generation of the two optical waves involved in the sensing process. The technique is based on obtaining the pump and probe waves by passive optical filtering of the spectral components generated in a single optical source that is driven by a pulsed RF signal. The optical source is a compact laser with integrated electroabsorption modulator and the optical filters are based on fiber Bragg gratings. Proof-of-concept experiments demonstrate 1 m spatial resolution over a 20 km sensing fiber with a 0.9 MHz precision in the measurement of the Brillouin frequency shift, a performance similar to that of much more complex setups. Furthermore, we discuss the factors limiting the sensor performance, which are basically related to residual spectral components in the filtering process. H. Iribas, J. Urricelqui, J. Mariñelarena, M. Sagues, and A. Loayssa Copyright © 2016 H. Iribas et al. All rights reserved. A New Technique for Integrating MEMS-Based Low-Cost IMU and GPS in Vehicular Navigation Wed, 08 Jun 2016 06:10:57 +0000 http://www.hindawi.com/journals/js/2016/5365983/ In providing acceptable navigational solutions, Location-Based Services (LBS) in land navigation rely mostly on integration of Global Positioning System (GPS) and Inertial Navigation System (INS) measurements for accuracy and robustness. The GPS/INS integrated system can provide better land-navigation solutions than the ones any standalone system can provide. Low-cost Inertial Measurement Units (IMUs), based on Microelectromechanical Systems (MEMS) technology, revolutionized the land-navigation system by virtue of their low-cost miniaturization and widespread availability. However, their accuracy is strongly affected by their inherent systematic and stochastic errors, which depend mainly on environmental conditions. The environmental noise and nonlinearities prevent obtaining optimal localization estimates in Land Vehicular Navigation (LVN) while using traditional Kalman Filters (KF). The main goal of this paper is to effectively eliminate stochastic errors of MEMS-based IMUs. The proposed solution is divided into two main components: (1) improving noise cancellation, using advanced stochastic error models in MEMS-based IMUs based on combined Autoregressive Processes (ARP) and first-order Gauss-Markov Process (1GMP), and (2) modeling the low-cost GPS/INS integration, using a hybrid Fuzzy Inference System (FIS) and Second-Order Extended Kalman Filter (SOEKF). The results obtained show that the proposed methods perform better than the traditional techniques do in different stochastic and dynamic situations. Neda Navidi, René Jr. Landry, Jianhua Cheng, and Denis Gingras Copyright © 2016 Neda Navidi et al. All rights reserved. A WSN-Based Intrusion Alarm System to Improve Safety in Road Work Zones Tue, 07 Jun 2016 11:29:02 +0000 http://www.hindawi.com/journals/js/2016/7048141/ Road traffic accidents are one of the main causes of death and disability worldwide. Workers responsible for maintaining and repairing roadways are especially prone to suffer these events, given their exceptional exposure to traffic. Since these actuations usually coexist with regular traffic, an errant driver can easily intrude the work area and provoke a collision. Some authors have proposed mechanisms aimed at detecting breaches in the work zone perimeter and alerting workers, which are collectively called intrusion alarm systems. However, they have several limitations and have not yet fulfilled the necessities of these scenarios. In this paper, we propose a new intrusion alarm system based on a Wireless Sensor Network (WSN). Our system is comprised of two main elements: vehicle detectors that form a virtual barrier and detect perimeter breaches by means of an ultrasonic beam and individual warning devices that transmit alerts to the workers. All these elements have a wireless communication interface and form a network that covers the whole work area. This network is in charge of transmitting and routing the alarms and coordinates the behavior of the system. We have tested our solution under real conditions with satisfactory results. Jose Martin, Alba Rozas, and Alvaro Araujo Copyright © 2016 Jose Martin et al. All rights reserved. Self-Monitoring Strengthening System Based on Carbon Fiber Laminate Thu, 02 Jun 2016 11:39:57 +0000 http://www.hindawi.com/journals/js/2016/3947513/ Externally bonded composites reinforced with high-strength fibers are increasingly popular in construction, especially in structures’ strengthening, where the best possible mechanical properties are required. At the same time the ability to autodetect threats is one of the most desirable features of contemporary structures. The authors of the paper have developed an intelligent fabric, wherein the carbon fibers play the role of not only tensile reinforcement but also strain sensor. The idea is based on the construction of the strain gauge, where the thread of carbon fibers arranged in zig-zag pattern works as electrical conductor and is insulated by parallel thread of glass or acrylic fibers. Preliminary laboratory tests were designed to create effective measurement techniques and assess the effectiveness of the strengthening of selected building structures, as reinforced concrete and timber beams. Presented in the paper, selected results of these studies are very promising, although there were some noted problems to be considered in next steps. The main problem here is the control of the cross section of the fibers tow, affecting the total resistance of the fabric. One of the main deficiencies of the proposed solution is also sensitivity to moisture. Rafal Krzywon, Marcin Gorski, Szymon Dawczynski, Leszek Szojda, Joao Castro Gomes, and Rita Salvado Copyright © 2016 Rafal Krzywon et al. All rights reserved. Research on Algorithm of Three-Dimensional Wireless Sensor Networks Node Localization Thu, 02 Jun 2016 07:57:38 +0000 http://www.hindawi.com/journals/js/2016/2745109/ This paper proposes a three-dimensional wireless sensor networks node localization algorithm based on multidimensional scaling anchor nodes, which is used to realize the absolute positioning of unknown nodes by using the distance between the anchor nodes and the nodes. The core of the proposed localization algorithm is a kind of repeated optimization method based on anchor nodes which is derived from STRESS formula. The algorithm employs the Tunneling Method to solve the local minimum problem in repeated optimization, which improves the accuracy of the optimization results. The simulation results validate the effectiveness of the algorithm. Random distribution of three-dimensional wireless sensor network nodes can be accurately positioned. The results satisfy the high precision and stability requirements in three-dimensional space node location. Jiang Minlan, Luo Jingyuan, and Zou Xiaokang Copyright © 2016 Jiang Minlan et al. All rights reserved. Temperature Optimized Ammonia and Ethanol Sensing Using Ce Doped Tin Oxide Thin Films in a Novel Flow Metric Gas Sensing Chamber Wed, 01 Jun 2016 13:50:31 +0000 http://www.hindawi.com/journals/js/2016/7652450/ A simple process of gas sensing is represented here using Ce doped tin oxide nanomaterial based thin film sensor. A novel flow metric gas chamber has been designed and utilized for gas sensing. Doping plays a vital role in enhancing the sensing properties of nanomaterials. Ce doped tin oxide was prepared by hydrothermal method and the same has been used to fabricate a thin film for sensing. The microstructure and morphology of the prepared materials were analysed by SEM, XRD, and FTIR analysis. The SEM images clearly show that doping can clamp down the growth of the large crystallites and can lead to large agglomeration spheres. Thin film gas sensors were formed from undoped pure SnO2 and Ce doped SnO2. The sensors were exposed to ammonia and ethanol gases. The responses of the sensors to different concentrations (50–500 ppm) of ammonia and ethanol at different operating temperatures (225°C–500°C) were studied. Results show that a good sensitivity towards ammonia was obtained with Ce doped SnO2 thin film sensor at an optimal operating temperature of 325°C. The Ce doped sensor also showed good selectivity towards ammonia when compared with ethanol. Pure SnO2 showed good sensitivity with ethanol when compared with Ce doped SnO2 thin film sensor. Response time of the sensor and its stability were also studied. K. Govardhan and Andrews Nirmala Grace Copyright © 2016 K. Govardhan and Andrews Nirmala Grace. All rights reserved. Carrier Current Line Systems Technologies in M2M Architecture for Wireless Communication Wed, 01 Jun 2016 11:53:09 +0000 http://www.hindawi.com/journals/js/2016/2652310/ This paper investigates the Carrier Current Line Systems (CCLS) technologies of Machine to Machine (M2M) architecture which applied for mobile station coverage working with metro, high speed railway, and subway such as analysis for public transport of an indoor transition system. It is based on the theory and practical engineering principle which provide guidelines and formulas for link budget design to help designers fully control and analyze the single output power of uplink and downlink between Fiber Repeaters (FR) and mobile station as well as base station. Finally, the results of this leakage cable system are successfully applied to indoor coverage design for metro rapid transit system which are easily installed cellular over fiber solutions for WCDMA/LTE access is becoming Ubiquitous Network to Internet of Thing (IOT) real case hierarchy of telecommunication. Hua-Ching Chen, Chia-Lun Wu, Jwo-Shiun Sun, and Hsuan-Ming Feng Copyright © 2016 Hua-Ching Chen et al. All rights reserved. Research on Coal Exploration Technology Based on Satellite Remote Sensing Wed, 01 Jun 2016 08:40:27 +0000 http://www.hindawi.com/journals/js/2016/8214801/ Coal is the main source of energy. In China and Vietnam, coal resources are very rich, but the exploration level is relatively low. This is mainly caused by the complicated geological structure, the low efficiency, the related damage, and other bad situations. To this end, we need to make use of some advanced technologies to guarantee the resource exploration is implemented smoothly and orderly. Numerous studies show that remote sensing technology is an effective way in coal exploration and measurement. In this paper, we try to measure the distribution and reserves of open-air coal area through satellite imagery. The satellite picture of open-air coal mining region in Quang Ninh Province of Vietnam was collected as the experimental data. Firstly, the ENVI software is used to eliminate satellite imagery spectral interference. Then, the image classification model is established by the improved ELM algorithm. Finally, the effectiveness of the improved ELM algorithm is verified by using MATLAB simulations. The results show that the accuracies of the testing set reach 96.5%. And it reaches 83% of the image discernment precision compared with the same image from Google. Dong Xiao, Ba Tuan Le, Yachun Mao, Jinhong Jiang, Liang Song, and Shanjun Liu Copyright © 2016 Dong Xiao et al. All rights reserved. A Wavelet Based Multiscale Weighted Permutation Entropy Method for Sensor Fault Feature Extraction and Identification Mon, 30 May 2016 14:48:50 +0000 http://www.hindawi.com/journals/js/2016/9693651/ Sensor is the core module in signal perception and measurement applications. Due to the harsh external environment, aging, and so forth, sensor easily causes failure and unreliability. In this paper, three kinds of common faults of single sensor, bias, drift, and stuck-at, are investigated. And a fault diagnosis method based on wavelet permutation entropy is proposed. It takes advantage of the multiresolution ability of wavelet and the internal structure complexity measure of permutation entropy to extract fault feature. Multicluster feature selection (MCFS) is used to reduce the dimension of feature vector, and a three-layer back-propagation neural network classifier is designed for fault recognition. The experimental results show that the proposed method can effectively identify the different sensor faults and has good classification and recognition performance. Qiaoning Yang and Jianlin Wang Copyright © 2016 Qiaoning Yang and Jianlin Wang. 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.