Journal of Sensors The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Strain Monitoring of Widening Cement Concrete Pavement Subjected to Differential Settlement of Foundation Sun, 04 Oct 2015 07:03:54 +0000 This paper describes the use of a sensor based on a fiber Bragg grating (FBG), which is capable of reducing strain transfer errors, to measure the strain features within the top and bottom layers of a cement concrete pavement subject to different degrees of foundation settlement. Based on measured data, the characteristics of the distribution and the variation in the structure strain were analyzed in detail. By comparing the measured results with those obtained by means of finite element analysis, the proposed FBG-based sensor assembly was found to be capable of effectively monitoring the strain distribution in a cement concrete pavement, thus proving that the improved optical fiber grating strain sensor is a very promising solution for road pavement structural health monitoring. Xiaolin Weng, Yongtao Nie, and Junyuan Lu Copyright © 2015 Xiaolin Weng et al. All rights reserved. A Wearable Contactless Sensor Suitable for Continuous Simultaneous Monitoring of Respiration and Cardiac Activity Mon, 28 Sep 2015 08:37:09 +0000 A reliable system that can simultaneously and accurately monitor respiration and cardiac output would have great utility in healthcare applications. In this paper we present a novel approach to creating such a system. This noninvasive, low power, low cost, contactless sensor is suitable for continuous monitoring of respiration (tidal volume) and cardiac stroke volume. Furthermore, it is capable of delivering this data in true volume (i.e., mL). The current embodiment, specifically designed for sleep monitoring applications, requires only 100 mW when powered by a 4.8 V battery pack and is based on the use of a single electroresistive band embedded in a T-shirt. Here, we describe the implementation of the device, explaining the rational and design choices for the electronic circuit and the physical garment together with the preliminary tests performed using one volunteer subject. Comparison of the device with a commercially available spirometer demonstrates that tidal volume can be monitored over extended periods with a precision of ±10%. We further demonstrate the utility of the device to measure cardiac output and respiration effort. Gaetano D. Gargiulo, Upul Gunawardana, Aiden O’Loughlin, Mohammad Sadozai, Elham Shabani Varaki, and Paul P. Breen Copyright © 2015 Gaetano D. Gargiulo et al. All rights reserved. An In-Vehicle Application Providing System Based on Driver’s Biodata Sun, 27 Sep 2015 07:14:11 +0000 The recent technologies for vehicular networks including wireless communication have allowed vehicles to provide biosensor based various applications to a driver. This paper proposes a system to provide a driver with the application which the driver wants in a vehicle using driver’s biodata. The proposed system is composed of four components including a sensing unit, an inference unit, an application providing unit, and vehicular network unit. In this paper, the experiments were performed for correlation investigation between the number of biodata and the reliability of driver’s characteristics extraction. We found that the number of the data used had a significant influence on improving the driver’s satisfaction level, playing an important role in reflecting driver’s status. Experiments using actual vehicles are conducted to examine the effectiveness of the proposed system, and the results are analyzed and discussed. The results on the investigation of detection of biodata in gasoline and diesel vehicles by the experiments are also given. We confirmed that the proposed sensing method was capable of accurate detection irrespective of vehicle mode and vehicle type. Kwang-Ho Seok and Yoon Sang Kim Copyright © 2015 Kwang-Ho Seok and Yoon Sang Kim. All rights reserved. Trends in Biosensors for HPV: Identification and Diagnosis Sun, 20 Sep 2015 07:36:11 +0000 The conventional methodologies used for the detection of human papillomavirus (HPV) present actually robust and reproducible advantages. However, at the same time, they involve complex protocols that sometimes are difficult to popularize. Over the first half of XX century, the adequate treatment of complex and delicate processes from a simple instrumental base seemed a fundamental and intrinsic contradiction. However, interdisciplinary trends have allowed the manipulation of tissues, proteins, and nucleic acids through innovative increasingly smaller devices. The proper diagnosis of HPV has seen great advances since biosensor researchers are employing its virus strains as models to study the interactions between the biorecognition element and the transducer. Additionally, all recent improvements and trends that material sciences, biotechnology, and data processing scientists excel for biosensors can be applied for the HPV detection platforms. In this review, we highlight the recent trends on materials, nanomaterials, and transducers for the specific detection and differentiation of HPV strains. The most influential methods for the detection and identification of these papillomaviruses include optical, electrochemical, and piezoelectric transducers; we will visit their sensibility and advantages. Additionally, we highlight the factors that contributed to the increasing importance of these biodevices as potential substitutes to conventional diagnostic methods. Isaac A. M. Frías, Karen Y. P. S. Avelino, Rafael R. Silva, César A. S. Andrade, and Maria D. L. Oliveira Copyright © 2015 Isaac A. M. Frías et al. All rights reserved. Interdigital Piezopolymer Transducers for Time of Flight Measurements with Ultrasonic Lamb Waves on Carbon-Epoxy Composites under Pure Bending Stress Sun, 20 Sep 2015 07:26:20 +0000 Interdigital transducers fabricated with piezopolymer film have been realized to excite ultrasonic Lamb waves in a composite laminate subjected to pure bending stresses. Lamb waves were generated and detected in a cross-ply [0°/90°] 4 mm thick carbon-fiber composite, by using two interdigital transducers in pitch-catch configuration. We demonstrate that the choice of the piezopolymer transducer technology is suitable for this type of investigation and the advantages of the proposed transducer assembly and bonding are described. A full set-up is described to determine the relationship between the time of flight of the recorded signals and the applied bending moment. Interdigital transducers were designed according to simulations of the dispersion curves, in order to operate at a central frequency of 450 kHz. This frequency corresponds to a central wavelength of 16 mm and to a group velocity of about 6000 m/s for the first symmetric guided wave mode. The variations in the time of flight of ultrasonic recorded signals were measured as a function of the variations in the bending moment. The static and dynamic load tests were in good agreement with strain gage measurements performed in the micro deformation range (0–1400 µm/m). Andrea Bulletti and Lorenzo Capineri Copyright © 2015 Andrea Bulletti and Lorenzo Capineri. All rights reserved. Highly Sensitive Electrochemical Sensor for the Determination of 8-Hydroxy-2′-deoxyguanosine Incorporating SWCNTs-Nafion Composite Film Sun, 13 Sep 2015 13:30:39 +0000 8-Hydroxy-2′-deoxyguanosine (8-OHdG) is a typical biomarker of oxidative DNA damage and has attracted much attention in recent years since the level of 8-OHdG in body fluids is typically associated with various diseases. In this work, a simple and highly sensitive electrochemical sensor for the determination of 8-OHdG was fabricated incorporating single wall carbon nanotubes- (SWCNTs-) Nafion composite film coated on glassy carbon electrode. Nafion was chosen as an optimal adhesive agent from a series of adhesive agents and acted as a binder, enrichment, and exclusion film. Due to the strong cation-exchange ability of Nafion and the outstanding electronic properties of SWCNTs, the prepared SWCNTs-Nafion film can strongly enhance the electrochemical response to oxidation of 8-OHdG and efficiently alleviate the interferences from uric acid and ascorbic acid. The oxidation peak currents are linear with the concentration of 8-OHdG in the range of 0.03 to 1.25 μM with a detection limit of 8.0 nM (S/N = 3). This work demonstrates that SWCNTs-Nafion film can improve the sensitivity, selectivity, reproducibility, and stability, making it an ideal candidate for electrochemical detection of 8-OHdG. Lingfei Yang, Bing Wang, Honglan Qi, Qiang Gao, Chen-zhong Li, and Chengxiao Zhang Copyright © 2015 Lingfei Yang et al. All rights reserved. Design and Optimization of a Low Power Pressure Sensor for Wireless Biomedical Applications Sun, 13 Sep 2015 13:29:18 +0000 A blood pressure sensor suitable for wireless biomedical applications is designed and optimized. State-of-the-art blood pressure sensors based on piezoresistive transducers in a full Wheatstone bridge configuration use low ohmic values because of relatively high sensitivity and low noise approach resulting in high power consumption. In this paper, the piezoresistance values are increased in order to reduce by one order of magnitude the power consumption in comparison with literature approaches. The microelectromechanical system (MEMS) pressure sensor, the mixed signal circuits signal conditioning circuitry, and the successive approximation register (SAR) analog-to-digital converter (ADC) are designed, optimized, and integrated in the same substrate using a commercial 1 μm CMOS technology. As result of the optimization, we obtained a digital sensor with high sensitivity, low noise (0.002 μV/Hz), and low power consumption (358 μW). Finally, the piezoresistance noise does not affect the pressure sensor application since its value is lower than half least significant bit (LSB) of the ADC. J. Sosa, Juan A. Montiel-Nelson, R. Pulido, and Jose C. Garcia-Montesdeoca Copyright © 2015 J. Sosa et al. All rights reserved. Optical Fiber Sensors Based on Nanoparticle-Embedded Coatings Sun, 06 Sep 2015 11:41:56 +0000 The use of nanoparticles (NPs) in scientific applications has attracted the attention of many researchers in the last few years. The use of NPs can help researchers to tune the physical characteristics of the sensing coating (thickness, roughness, specific area, refractive index, etc.) leading to enhanced sensors with response time or sensitivity better than traditional sensing coatings. Additionally, NPs also offer other special properties that depend on their nanometric size, and this is also a source of new sensing applications. This review focuses on the current status of research in the use of NPs within coatings in optical fiber sensing. Most used sensing principles in fiber optics are briefly described and classified into several groups: absorbance-based sensors, interferometric sensors, fluorescence-based sensors, fiber grating sensors, and resonance-based sensors, among others. For each sensor group, specific examples of the utilization of NP-embedded coatings in their sensing structure are reported. Aitor Urrutia, Javier Goicoechea, and Francisco J. Arregui Copyright © 2015 Aitor Urrutia et al. All rights reserved. Low-Cost and Energy-Saving Wireless Sensor Network for Real-Time Urban Mobility Monitoring System Sun, 06 Sep 2015 11:41:46 +0000 This paper presents a low-cost and energy-saving urban mobility monitoring system based on wireless sensor networks (WSNs). The primary components of the proposed sensor unit are a Bluetooth sensor and a Zigbee transceiver. Within the WSN, the Bluetooth sensor captures the MAC addresses of Bluetooth units equipped in mobile devices and car navigation systems. The Zigbee transceiver transmits the collected MAC addresses to a data center without any major communications infrastructures (e.g., fiber optics and 3G/4G network). A total of seven prototype sensor units have been deployed on roadway segments in Newark, New Jersey, for a proof of concept (POC) test. The results of the POC test show that the performance of the proposed sensor unit appears promising, resulting in 2% of data drop rates and an improved Bluetooth capturing rate. Joyoung Lee, Zijia Zhong, Bo Du, Slobodan Gutesa, and Kitae Kim Copyright © 2015 Joyoung Lee et al. All rights reserved. Low-Cost Open-Source Voltage and Current Monitor for Gas Metal Arc Weld 3D Printing Sun, 30 Aug 2015 09:36:26 +0000 Arduino open-source microcontrollers are well known in sensor applications for scientific equipment and for controlling RepRap 3D printers. Recently low-cost open-source gas metal arc weld (GMAW) RepRap 3D printers have been developed. The entry-level welders used have minimal controls and therefore lack any real-time measurement of welder voltage or current. The preliminary work on process optimization of GMAW 3D printers requires a low-cost sensor and data logger system to measure welder current and voltage. This paper reports on the development of a low-cost open-source power measurement sensor system based on Arduino architecture. The sensor system was designed, built, and tested with two entry-level MIG welders. The full bill of materials and open source designs are provided. Voltage and current were measured while making stepwise adjustments to the manual voltage setting on the welder. Three conditions were tested while welding with steel and aluminum wire on steel substrates to assess the role of electrode material, shield gas, and welding velocity. The results showed that the open source sensor circuit performed as designed and could be constructed for <$100 in components representing a significant potential value through lateral scaling and replication in the 3D printing community. A. Pinar, B. Wijnen, G. C. Anzalone, T. C. Havens, P. G. Sanders, and J. M. Pearce Copyright © 2015 A. Pinar et al. All rights reserved. Feedforward Neural Network for Force Coding of an MRI-Compatible Tactile Sensor Array Based on Fiber Bragg Grating Sun, 30 Aug 2015 08:38:48 +0000 This work shows the development and characterization of a fiber optic tactile sensor based on Fiber Bragg Grating (FBG) technology. The sensor is a 3 3 array of FBGs encapsulated in a PDMS compliant polymer. The strain experienced by each FBG is transduced into a Bragg wavelength shift and the inverse characteristics of the sensor were computed by means of a feedforward neural network. A 21 mN RMSE error was achieved in estimating the force over the 8 N experimented load range while including all probing sites in the neural network training procedure, whereas the median force RMSE was 199 mN across the 200 instances of a Monte Carlo randomized selection of experimental sessions to evaluate the calibration under generalized probing conditions. The static metrological properties and the possibility to fabricate sensors with relatively high spatial resolution make the proposed design attractive for the sensorization of robotic hands. Furthermore, the proved MRI-compatibility of the sensor opens other application scenarios, such as the possibility to employ the array for force measurement during functional MRI-measured brain activation. Paola Saccomandi, Calogero Maria Oddo, Loredana Zollo, Domenico Formica, Rocco Antonio Romeo, Carlo Massaroni, Michele Arturo Caponero, Nicola Vitiello, Eugenio Guglielmelli, Sergio Silvestri, and Emiliano Schena Copyright © 2015 Paola Saccomandi et al. All rights reserved. GAECH: Genetic Algorithm Based Energy Efficient Clustering Hierarchy in Wireless Sensor Networks Mon, 17 Aug 2015 14:10:06 +0000 Clustering the Wireless Sensor Networks (WSNs) is the major issue which determines the lifetime of the network. The parameters chosen for clustering should be appropriate to form the clusters according to the need of the applications. Some of the well-known clustering techniques in WSN are designed only to reduce overall energy consumption in the network and increase the network lifetime. These algorithms achieve increased lifetime, but at the cost of overloading individual sensor nodes. Load balancing among the nodes in the network is also equally important in achieving increased lifetime. First Node Die (FND), Half Node Die (HND), and Last Node Die (LND) are the different metrics for analysing lifetime of the network. In this paper, a new clustering algorithm, Genetic Algorithm based Energy efficient Clustering Hierarchy (GAECH) algorithm, is proposed to increase FND, HND, and LND with a novel fitness function. The fitness function in GAECH forms well-balanced clusters considering the core parameters of a cluster, which again increases both the stability period and lifetime of the network. The experimental results also clearly indicate better performance of GAECH over other algorithms in all the necessary aspects. B. Baranidharan and B. Santhi Copyright © 2015 B. Baranidharan and B. Santhi. All rights reserved. Mobile Device Based Dynamic Key Management Protocols for Wireless Sensor Networks Sun, 16 Aug 2015 13:14:16 +0000 In recent years, wireless sensor network (WSN) applications have tended to transmit data hop by hop, from sensor nodes through cluster nodes to the base station. As a result, users must collect data from the base station. This study considers two different applications: hop by hop transmission of data from cluster nodes to the base station and the direct access to cluster nodes data by mobile users via mobile devices. Due to the hardware limitations of WSNs, some low-cost operations such as symmetric cryptographic algorithms and hash functions are used to implement a dynamic key management. The session key can be updated to prevent threats of attack from each communication. With these methods, the data gathered in wireless sensor networks can be more securely communicated. Moreover, the proposed scheme is analyzed and compared with related schemes. In addition, an NS2 simulation is developed in which the experimental results show that the designed communication protocol is workable. Chin-Ling Chen, Chih-Cheng Chen, and De-Kui Li Copyright © 2015 Chin-Ling Chen et al. All rights reserved. Binding Quantum Dots to Silk Biomaterials for Optical Sensing Sun, 16 Aug 2015 13:10:03 +0000 Quantum dots (QDs), have great potential for fabricating optical sensing devices and imaging biomaterial degradation in vivo. In the present study, 2-mercaptoethylamine- (MEA-) and mercaptopropionic acid- (MPA-) capped CdTe-QDs were physically incorporated in silk films that contained a high content (>30%) of crystalline beta-sheet structure. The beta-sheets were induced by the addition of glycerol, water annealing, glycerol/annealing, or treatment with methanol. Incorporation of QDs did not influence the formation of beta-sheets. When the films were extracted with water, most QDs remained associated with the silk, based on the retention of photoluminescence in the silk films and negligible photoluminescence in the extracts. Compared to the solution state, photoluminescence intensity significantly decreased for MEA-QDs but not for MPA-QDs in the silk films, while the emission maximum blue shifted (≈4 nm) slightly for both. Further film digestion using protease XIV, alpha-chymotrypsin, and the combination of the two proteases suggested that QDs may be bound to the silk beta-sheet regions but not the amorphous regions. QDs photoluminescence in silk films was quenched when the concentration of hydrogen peroxide (H2O2) was above 0.2-0.3 mM, indicating the QDs-incorporated silk films can be used to report oxidation potential in solution. Disi Lu, Zhaozhu Zheng, Shaozhe Guo, Cheng Wang, David L. Kaplan, and Xiaoqin Wang Copyright © 2015 Disi Lu et al. All rights reserved. A Low-Power Microcontroller with Accuracy-Controlled Event-Driven Signal Processing Unit for Rare-Event Activity-Sensing IoT Devices Sun, 16 Aug 2015 13:04:27 +0000 A specially designed microcontroller with event-driven sensor data processing unit (EPU) is proposed to provide energy-efficient sensor data acquisition for Internet of Things (IoT) devices in rare-event human activity sensing applications. Rare-event sensing applications using a remotely installed IoT sensor device have a property of very long event-to-event distance, so that the inaccurate sensor data processing in a certain range of accuracy error is enough to extract appropriate events from the collected sensing data. The proposed signal-to-event converter (S2E) as a preprocessor of the conventional sensor interface extracts a set of atomic events with the specific features of interest and performs an early evaluation for the featured points of the incoming sensor signal. The conventional sensor data processing such as DSPs or software-driven algorithm to classify the meaningful event from the collected sensor data could be accomplished by the proposed event processing unit (EPU). The proposed microcontroller architecture enables an energy efficient signal processing for rare-event sensing applications. The implemented system-on-chip (SoC) including the proposed building blocks is fabricated with additional 7500 NAND gates and 1-KB SRAM tracer in 0.18 um CMOS process, consuming only 20% compared to the conventional sensor data processing method for human hand-gesture detection. Daejin Park, Jonghee M. Youn, and Jeonghun Cho Copyright © 2015 Daejin Park et al. All rights reserved. Automated Space Classification for Network Robots in Ubiquitous Environments Sun, 16 Aug 2015 12:35:45 +0000 Network robots provide services to users in smart spaces while being connected to ubiquitous instruments through wireless networks in ubiquitous environments. For more effective behavior planning of network robots, it is necessary to reduce the state space by recognizing a smart space as a set of spaces. This paper proposes a space classification algorithm based on automatic graph generation and naive Bayes classification. The proposed algorithm first filters spaces in order of priority using automatically generated graphs, thereby minimizing the number of tasks that need to be predefined by a human. The filtered spaces then induce the final space classification result using naive Bayes space classification. The results of experiments conducted using virtual agents in virtual environments indicate that the performance of the proposed algorithm is better than that of conventional naive Bayes space classification. Jiwon Choi, Seoungjae Cho, Phuong Chu, Hoang Vu, Kyhyun Um, and Kyungeun Cho Copyright © 2015 Jiwon Choi et al. All rights reserved. A Study on High Secure and Efficient MANET Routing Scheme Sun, 16 Aug 2015 12:00:56 +0000 In mobile ad hoc networks (MANETs), the more applications we use, the more security is required. In this paper, we propose a high secure and efficient routing scheme that not only satisfies the properties of anonymity, security, authentication, nonrepudiation, and unforgeability that the previous paper achieved for ad hoc networks, but also satisfies other necessary properties such as confidentiality, traceability, and flexibility for multipaths in order to make the ad hoc environment more secure and practicable. Wei-Chen Wu and Horng-Twu Liaw Copyright © 2015 Wei-Chen Wu and Horng-Twu Liaw. All rights reserved. Electrodes Modification Based on Metal-Free Phthalocyanine: Example of Electrochemical Sensors for the Detection of Acetic Acid Sun, 16 Aug 2015 07:04:35 +0000 Electroanalytical properties of tetra-tert-butyl phthalocyanine (PcH2-tBu) modified electrodes are studied by cyclic voltammetry (CV). The modified electrodes are obtained by CV deposition techniques on gold (Au) and glassy carbon (C) screen-printed electrodes (SPEs) and used for the electrochemical detection of acetic acid (AA). Based on the CV experiments, the electrodeposition mechanism is detailed. The modified PcH2-tBu electrodes reveal one oxidation and one reduction peak within the potential window of the working electrodes. In the presence of the analyte (acetic acid), the modified electrodes show sensitivity in the range of 10 mM to 400 mM. For the PcH2-tBu modified Au electrode, a limit of detection (LOD) of 5.89 mM (based on the +0.06 V peak) was obtained while for the PcH2-tBu modified C electrode a LOD of 17.76 mM (based on the +0.07 V peak) was achieved. A signal decay of 17%, based on 20 experiments, is obtained when gold is used as working electrode. If carbon is used as working electrode a value of 7% is attained. A signal decay is observed after more than 50 cycles of experiments and is more pronounced when higher concentrations of acetic acid are used. A mechanism of sensing is proposed at the end. Amadou L. Ndiaye, Alain Pauly, Sebastien Delile, Jérôme Brunet, Christelle Varenne, and Abhishek Kumar Copyright © 2015 Amadou L. Ndiaye et al. All rights reserved. Performance Improvement of Inertial Navigation System by Using Magnetometer with Vehicle Dynamic Constraints Mon, 10 Aug 2015 13:34:21 +0000 A navigation algorithm is proposed to increase the inertial navigation performance of a ground vehicle using magnetic measurements and dynamic constraints. The navigation solutions are estimated based on inertial measurements such as acceleration and angular velocity measurements. To improve the inertial navigation performance, a three-axis magnetometer is used to provide the heading angle, and nonholonomic constraints (NHCs) are introduced to increase the correlation between the velocity and the attitude equation. The NHCs provide a velocity feedback to the attitude, which makes the navigation solution more robust. Additionally, an acceleration-based roll and pitch estimation is applied to decrease the drift when the acceleration is within certain boundaries. The magnetometer and NHCs are combined with an extended Kalman filter. An experimental test was conducted to verify the proposed method, and a comprehensive analysis of the performance in terms of the position, velocity, and attitude showed that the navigation performance could be improved by using the magnetometer and NHCs. Moreover, the proposed method could improve the estimation performance for the position, velocity, and attitude without any additional hardware except an inertial sensor and magnetometer. Therefore, this method would be effective for ground vehicles, indoor navigation, mobile robots, vehicle navigation in urban canyons, or navigation in any global navigation satellite system-denied environment. Daehee Won, Jongsun Ahn, Sangkyung Sung, Moonbeom Heo, Sung-Hyuck Im, and Young Jae Lee Copyright © 2015 Daehee Won et al. All rights reserved. Correcting Air-Pressure Data Collected by MEMS Sensors in Smartphones Thu, 06 Aug 2015 11:19:55 +0000 We present a novel correction method for air-pressure data collected by microelectromechanical pressure sensors embedded in Android-based smartphones, in order to render them usable as meteorological data. The first step of the proposed correction method involves removing the mechanically derived outliers existing beyond the physical limits and those existing outside 3σ, as well as a reduction to the mean sea level pressure using the altitude data from digital elevation models. The second correction step involves classifying data by location and linear-regression analysis utilizing the temperature and humidity sensed by the smartphone to reduce correction errors by performing the analysis according to personalized settings. Air-pressure data obtained from smartphones is subject to several influential factors, depending on the users’ external environment. However, once corrected for spatial location, temperature, and humidity and for individual users after a comprehensive quality control, the corrected air-pressure data was highly reliable as an auxiliary resource for automatic weather stations. Na-Young Kim, Yong-Hyuk Kim, Yourim Yoon, Hyo-Hyuc Im, Reno K. Y. Choi, and Yong Hee Lee Copyright © 2015 Na-Young Kim et al. All rights reserved. The Binding of EGFR to GM1(3) Hosted in Lipid Raft-Like Biomembranes Insighted by Plasmonic Resonance Techniques Thu, 06 Aug 2015 09:47:50 +0000 We exploit Au/SiO2 plasmonic structures to check the effective binding activity of GM1(3) gangliosides hosted in physiological-like biomembranes, in presence of the Epidermal Growth Factor Receptor (EGFR). To this aim, we used bilayers that support the propagation of optical surface plasmon modes (plasmonic transducers, PTs) or guided modes (Plasmon Waveguide Resonators, PWRs). First, we measured the binding of EGFR to GM1(3) by using PTs. Indeed, effective interactions were evidenced, but with faint signals that prevented resolving dissociation kinetics. In order to enhance the optical responses, we turned our attention to PWRs. We first refined the design of a previously adopted Au/SiO2 PWR, finding that the nominal sensitivity is independent on SiO2 thickness but strongly dependent on its residual losses, due typically to a nonoptimal deposition process. We fabricated an improved Au/SiO2 resonator and tested the predicted signal enhancement by monitoring the binding of EGFR to GM3-enriched biomembranes. The measured signal was ~12-fold higher than that one measured using a PT, close to the maximum theoretical enhancement. The higher PWR response enabled us to detect the dissociation of EGFR from GM3, and the value of the apparent dissociation constant of the GM3-EGFR complex could be obtained. Giancarlo Margheri, Silvana Trigari, Stefano Sottini, Riccardo D’Agostino, Tommaso Del Rosso, and Mario Del Rosso Copyright © 2015 Giancarlo Margheri et al. All rights reserved. Bicriteria Optimization in Wireless Sensor Networks: Link Scheduling and Energy Consumption Tue, 04 Aug 2015 11:33:58 +0000 Link scheduling is important for reliable data communication in wireless sensor networks. Previous works mainly focus on how to find the minimum scheduling length but ignore the impact of energy consumption. In this paper, we integrate them together and solve them by multiobjective genetic algorithms. As a contribution, by jointly modeling the route selection and interference-free link scheduling problem, we give a systematical analysis on the relationship between link scheduling and energy consumption. Considering the specific many-to-one communication nature of WSNs, we propose a novel link scheduling scheme based on NSGA-II (Non-dominated Sorting Genetic Algorithm II). Our approach aims to search the optimal routing tree which satisfies the minimum scheduling length and energy consumption for wireless sensor networks. To achieve this goal, the solution representation based on the routing tree, the genetic operations including tree based recombination and mutation, and the fitness evaluation based on heuristic link scheduling algorithm are well designed. Extensive simulations demonstrate that our algorithm can quickly converge to the Pareto optimal solution between the two performance metrics. Jian Chen, Jie Jia, Enliang Dai, Yingyou Wen, and Dazhe Zhao Copyright © 2015 Jian Chen et al. All rights reserved. An Asynchronous Periodic Sequential Pattern Mining Algorithm with Multiple Minimum Item Supports for Ad Hoc Networking Tue, 04 Aug 2015 11:27:56 +0000 The original sequential pattern mining model only considers occurrence frequencies of sequential patterns, disregarding their occurrence periodicity. We propose an asynchronous periodic sequential pattern mining model to discover the sequential patterns that not only occur frequently but also appear periodically. For this mining model, we propose a pattern-growth mining algorithm to mine asynchronous periodic sequential patterns with multiple minimum item supports. This algorithm employs a divide-and-conquer strategy to mine asynchronous periodic sequential patterns in a depth-first manner recursively. We describe the process of algorithm realization and demonstrate the efficiency and stability of the algorithm through experimental results. Xiangzhan Yu, Zhaoxin Zhang, Haining Yu, Feng Jiang, and Wen Ji Copyright © 2015 Xiangzhan Yu et al. All rights reserved. Recent Advances in Security and Privacy for Wireless Sensor Networks Tue, 04 Aug 2015 11:17:04 +0000 Fei Yu, Chin-Chen Chang, Jian Shu, Iftikhar Ahmad, Jun Zhang, and Jose Maria de Fuentes Copyright © 2015 Fei Yu et al. All rights reserved. Heuristic Approach to Select Opportunistic Routing Forwarders (HASORF) to Enhance Throughput for Wireless Sensor Networks Tue, 04 Aug 2015 11:11:30 +0000 Biological schemes provide useful resources for designing adaptive routing protocols for wireless sensor networks (WSNs). The key idea behind using bioinspired routing is to find the optimal path to the destination. Similarly, the idea of opportunistic routing (OR) is to find the least number of hops to deliver the data to the destination. Numerous routing schemes have been proposed in WSNs while targeting various performance goals, such as throughput, delay, and link quality. Recently, OR schemes have come onto the scene in comparison with the traditional routing algorithms. The performance of OR schemes, however, highly depends on the selection of forwarder nodes. In this paper, we consider a chain network topology, where nodes are separated by an equal distance. The throughput of the chain network is analyzed mathematically, and based on the analysis results, a heuristic algorithm is proposed to choose the forwarder nodes. We evaluate the performance of the proposed Heuristic Approach to Select Opportunistic Routing Forwarders (HASORF) by using the ns-2 simulator and compare it with previous schemes, such as random routing, Extremely Opportunistic Routing (ExOR), and Simple Opportunistic Adaptive Routing (SOAR). The empirical results show that our proposed scheme achieves the best performance among them. Yousaf Bin Zikria, Summera Nosheen, Jin-Ghoo Choi, and Sung Won Kim Copyright © 2015 Yousaf Bin Zikria et al. All rights reserved. An ID/Locator Separation Based Group Mobility Management in Wireless Body Area Network Tue, 04 Aug 2015 11:05:49 +0000 Mobility management in wireless sensor network is the most important factor to be considered for applications such as healthcare system. Recently, Identifier (ID)/Locator (LOC) separation based mobility management scheme has been proposed for wireless sensor network. However, it does not perform well in group-based mobility management in wireless body area network, and thus it tends to induce large registration, packet delivery, and handover delays. To overcome these limitations, we propose a group-based mobility management scheme based on ID/LOC separation concept for ID-based communications with location-based routing to reduce the number of control messages. In the proposed scheme, each sensor device has a globally unique device identifier (GDID) which contains the information of its home network domain. For handover support, each access gateway maintains its home GDID register (HGR) and visiting GDID register (VGR) which are used to keep the GDID-locator (LOC) mappings for primary mobile devices in the distributed manner. Besides, in the proposed scheme, only the coordinator will send Router Solicitation and Router Advertisement messages to reduce the control messages further. By numerical analysis, we show that the proposed scheme can significantly reduce the registration, packet delivery, and handover delays, compared to the existing schemes. Moneeb Gohar, Jin-Ghoo Choi, and Seok-Joo Koh Copyright © 2015 Moneeb Gohar et al. All rights reserved. A Novel Bioinspired Multiobjective Optimization Algorithm for Designing Wireless Sensor Networks in the Internet of Things Tue, 04 Aug 2015 10:33:45 +0000 The design of wireless sensor networks (WSNs) in the Internet of Things (IoT) faces many new challenges that must be addressed through an optimization of multiple design objectives. Therefore, multiobjective optimization is an important research topic in this field. In this paper, we develop a new efficient multiobjective optimization algorithm based on the chaotic ant swarm (CAS). Unlike the ant colony optimization (ACO) algorithm, CAS takes advantage of both the chaotic behavior of a single ant and the self-organization behavior of the ant colony. We first describe the CAS and its nonlinear dynamic model and then extend it to a multiobjective optimizer. Specifically, we first adopt the concepts of “nondominated sorting” and “crowding distance” to allow the algorithm to obtain the true or near optimum. Next, we redefine the rule of “neighbor” selection for each individual (ant) to enable the algorithm to converge and to distribute the solutions evenly. Also, we collect the current best individuals within each generation and employ the “archive-based” approach to expedite the convergence of the algorithm. The numerical experiments show that the proposed algorithm outperforms two leading algorithms on most well-known test instances in terms of Generational Distance, Error Ratio, and Spacing. Jun Huang, Liqian Xu, Cong-cong Xing, and Qiang Duan Copyright © 2015 Jun Huang et al. All rights reserved. A Self-Adaptive Wireless Sensor Network Coverage Method for Intrusion Tolerance Based on Trust Value Mon, 03 Aug 2015 13:19:40 +0000 The sensor is quite easily attacked or invaded during the process of the node coverage optimization. It is a great challenge to make sure that the wireless sensor network could still carry out a secure communication and reliable coverage under the condition of being attacked. Therefore, this paper proposes a network coverage method for intrusion tolerance based on trust value of nodes by combining the trust value model with the reliable coverage optimization. It first estimates trust value of nodes through which to regulate the perception radius and decision-making radius. Furthermore, this algorithm also combines the classical methods of wireless network coverage, such as GSO and PSO, to realize the networks coverage of invasive tolerant sensor. After comparing with the conventional single cover mechanism, it can improve the security and coverage rate of network under the condition of invasion. The simulation results verify the effectiveness of the algorithm. Zuo Chen, Xue Li, Bing Yang, and Qian Zhang Copyright © 2015 Zuo Chen et al. All rights reserved. Survey of Security Technologies on Wireless Sensor Networks Mon, 03 Aug 2015 12:13:20 +0000 Because of their low cost and adaptability, wireless sensor networks are widely used in civil, military, and commercial fields and other fields. However, since the sensor node in the calculation of the capacity, battery capacity, and storage capacity are restricted by the limitations and inherent characteristics of the sensor networks, compared to traditional networks, which makes wireless sensor networks face more security threats. This paper summarized research progress of sensor network security issues as three aspects, key management, authentication, and secure routing, analyzed and commented on these results advantages and disadvantages and pointed out the future direction of the hot research field. Qiuwei Yang, Xiaogang Zhu, Hongjuan Fu, and Xiqiang Che Copyright © 2015 Qiuwei Yang et al. All rights reserved. Accurately Identifying New QoS Violation Driven by High-Distributed Low-Rate Denial of Service Attacks Based on Multiple Observed Features Mon, 03 Aug 2015 12:09:44 +0000 We propose using multiple observed features of network traffic to identify new high-distributed low-rate quality of services (QoS) violation so that detection accuracy may be further improved. For the multiple observed features, we choose F feature in TCP packet header as a microscopic feature and, P feature and D feature of network traffic as macroscopic features. Based on these features, we establish multistream fused hidden Markov model (MF-HMM) to detect stealthy low-rate denial of service (LDoS) attacks hidden in legitimate network background traffic. In addition, the threshold value is dynamically adjusted by using Kaufman algorithm. Our experiments show that the additive effect of combining multiple features effectively reduces the false-positive rate. The average detection rate of MF-HMM results in a significant 23.39% and 44.64% improvement over typical power spectrum density (PSD) algorithm and nonparametric cumulative sum (CUSUM) algorithm. Jian Kang, Mei Yang, and Junyao Zhang Copyright © 2015 Jian Kang et al. All rights reserved.