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ABSTRACT: One of the most important issues in large-scale Wireless Sensor Networks (WSNs) is how to balance the energy consumption of sensor nodes. In this paper, we propose a novel approach for load balance using compressive sensing. Our approach offers accurate recovery of sampled data from a small number compressed data. Its performance is evaluated in TinyOS. Simulation results show that it achieves a good performance in terms of energy balancing among all nodes in a network. It outperforms the tree collection protocol stack.
Computational Science and Engineering (CSE), 2011 IEEE 14th International Conference on; 09/2011
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13th IEEE International Conference on High Performance Computing & Communication, HPCC 2011, Banff, Alberta, Canada, September 2-4, 2011; 01/2011
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ABSTRACT: In this paper, the accuracy of location estimation of ad hoc deployed sensor nodes for a wireless sensor network in the presence of noisy environment and obstacle is discussed. Considering estimation accuracy, energy efficiency, and range independency, we propose a localization scheme using a mobile anchor node equipped with a directional antenna based on the geometry technique, called LSWD: Localization Scheme for Wireless Sensor Networks using Directional Antenna, this scheme make use of directional antenna concentrates energy on a particularly direction with high gain and narrow covering area. Without increasing hardware and computational complexity, sensor nodes estimate their positions using the minimum number of beacon information. Our localization scheme is verified by network simulation software. The result shows that the proposed localization algorithm has higher accuracy and energy efficiency than other localization schemes.
IEEE Transactions on Consumer Electronics 12/2010; · 0.94 Impact Factor
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ABSTRACT: To make a SAW radio frequency identification (RFID) tag carry more information, it should consist of several reflectors. It is important to exactly know the related parameters of the tag in selected frequency band, such as propagation loss when it propagates on free surface of a SAW device, transduction coefficient of the IDT (interdigital transducer), and reflection and transmission coefficients of reflectors with different numbers of electrodes, widths of electrodes, or both. In this report, we propose a novel method which can obtain these parameters through experiments and data processing. We develop a new test-device structure with different numbers and widths of electrodes of reflectors fabricated in one device. All related tag parameters can be obtained simultaneously, which can greatly reduce the tag design cost.
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control 07/2010; · 1.69 Impact Factor
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ABSTRACT: This paper presents the thermal design and analysis of uncooled infrared sensor fabricated in SMIC standard 0.18μm CMOS technology. The steady-state and transient thermal simulations have been done by finite-element methods (FEM). The effects of membrane parameters on the thermal performance of the infrared sensor are investigated. The simulation results show that the thermal time constant and temperature rise of pixel are increasing with the size of absorbing layer increment, and the increment of width of polysilicon leads to the decrement of thermal time constant and temperature rise. In addition, to counterpoise these two thermal parameters, a group of the optimized thermally isolated membrane parameters is given.
Nano/Micro Engineered and Molecular Systems (NEMS), 2010 5th IEEE International Conference on; 02/2010
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2010 International Conference on Parallel and Distributed Computing, Applications and Technologies, PDCAT 2010, Wuhan, China, 8-11 December, 2010; 01/2010
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ABSTRACT: Based on finite element analysis, we propose a simulation model for radio frequency identification (RFID) SAW tag devices. Electric properties of metal electrode on substrate greatly affect the characteristics of the device and are discussed in the paper. Then the right and left boundary conditions for the device are applied to remove large unwanted waves generated by wave propagation near the boundaries. To save computation time, a 2-D model is proposed, where some mesh skills are applied. The tag device is simulated in 2 steps. First, we use modal analysis to get the device phase velocity and harmonic frequency. Second, a tag with multireflectors is simulated. Based on the simulations, we have designed and fabricated a SAW tag. A comparison is made between simulation and experimental results and shows our simulation model agrees with the experiment very well.
IEEE transactions on ultrasonics, ferroelectrics, and frequency control 09/2009; 56(8):1753-60. · 1.80 Impact Factor
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ABSTRACT: An improved ANSYS simulation model for SAW device is discussed. The electric properties of metal fingers which affect the characteristics of a device are simulated. The right and left boundary conditions for the device, which greatly affect the wanted signals, are proposed. To save simulation time, a 2D model is created, where some mesh skills are applied.
Industrial Electronics and Applications, 2009. ICIEA 2009. 4th IEEE Conference on; 06/2009
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ABSTRACT: It is always difficult to optimize parameters of capacitive micromachined ultrasonic transducers (CMUT) because of high computational cost of Finite Element Method (FEM) analysis and prototype manufacturing cost. Thus a theoretical model is required in designing a CMUT. This paper presents such a 1-D theoretical model for CMUT reception, which makes it easier to optimize the parameters of the CMUT with respect to output voltage and bandwidth. It also helps in understanding the influence of each parameter. A typical example is given for model verification. The results obtained from the proposed 1-D lumped model are compared to those from 3-D FEM simulation. Our 1-D theoretical model can be used to study the behavior of a CMUT reception at much lower computational cost without losing accuracy.
Intelligent Computation Technology and Automation (ICICTA), 2008 International Conference on; 11/2008
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ABSTRACT: It is always difficult to optimize parameters of capacitive micromachined ultrasonic transducers (CMUT) because of high computational time cost of finite element method (FEM) analysis and economic cost of prototype manufacturing. Thus a theoretical model is required in designing a CMUT. This paper presents such a 1-D lumped model. A transfer function between output sound pressure and input AC voltage has been deduced based on control theory. This model makes it easier to optimize the parameters of a CMUT with respect to output sound pressure and bandwidth and to understand the influence of each parameter. To derive the proposed 1-D model, transition from a 3-D CMUT device to 1-D lumped model is performed by FEM analysis. Finally a typical example is given for verification. The result obtained by the proposed 1-D lumped model is compared to that by 3-D FEM simulation. It shows that our proposed 1-D lumped model can be used to study the behavior of CMUT at much lower computational cost without losing accuracy.
Advanced Intelligent Mechatronics, 2008. AIM 2008. IEEE/ASME International Conference on; 08/2008
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ABSTRACT: In this paper, we present an energy efficient localization algorithm for wireless sensor networks using a mobile anchor node. It is based on the distance measurement with extra hardware. The mobile node is equipped with a GPS receiver, RF (radio frequency) and ultrasonic transmitter. Each stationary sensor node is equipped with a RF and ultrasonic receiver. The mobile node periodically broadcasts its location information, and stationary sensor nodes take the positions as virtual anchor points. A sensor nodepsilas location is computed by measuring the distance to the virtual anchor point using TDOA (time difference of arrival) method. After the first round localization is done, the un-localized sensor nodes can compute their locations with the help of localized stationary sensor nodes. Simulation results show that our proposed localization scheme outperforms the other localization schemes using mobile anchor nodes in energy efficiency and cost.
Information and Automation, 2008. ICIA 2008. International Conference on; 07/2008
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ABSTRACT: Sensor network reprogramming is a challenging problem and code dissemination is one of the important part in this subject. This paper proposes a novel TDMA-based code dissemination protocol which can greatly reduce the redundant message receptions and collisions in the dissemination process. We divide a program image into pages and page dissemination is in pipeline to reduce latency and achieve easy recovery. Since senders in the network frequently change their status, the static TDMA schedule is not efficient. On the other hand, the building of TDMA schedule before each page transmission is too complicated to use because of the high overhead. To overcome the problem, we propose a code dissemination protocol for nodes to learn local contending condition by overhearing normal messages or exchanging small amount of auxiliary messages when collision happens. Therefore the node can avoid receiving unwanted messages or making collisions with its neighbors. If no collision happens, auxiliary message exchange is unnecessary, otherwise the exchanged messages can help reduce future collisions. We implement our protocol in TinyOS-1.x with mica2 platform. The proposed protocol is simulated in TOSSIM and the simulation results show that our code dissemination protocol has better performance than Deluge.
Information and Automation, 2008. ICIA 2008. International Conference on; 07/2008
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ABSTRACT: Energy efficiency has been known as the most important problem in designing a data query system in wireless sensor networks (WSNs). In this paper, we propose a novel query method in which the clusters are constructed only in the query area as needed and destroyed after the query ends. To achieve this goal, we design and implement a Tree-Based Clustering (TBC) protocol to support upper layer applications. In TBC, clustering is combined with tree routing and all nodes in WSN use the same communication power. In addition, we adopt a simple approach to solve time synchronization problem among sensor nodes. Simulations show that our methods can save significant amount of energy comparing to HEED and MHRA protocols. The proposed query system is implemented on TinyOS and tested on the sensor nodes developed at Shenzhen Institute of Advanced Technology.
Information and Automation, 2008. ICIA 2008. International Conference on; 07/2008
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ABSTRACT: Localization is one of the crucial issues in wireless sensor networks. In range-based mechanisms, the nodes obtain pairwise distances or angles with extra hardware for high localization accuracy. On the other hand, the range-free schemes obtain lower localization accuracy at low hardware cost. To improve location accuracy, we present a three dimensional range-free localization scheme by using a mobile anchor node equipped with a GPS. The mobile anchor node carried in an aero plane flies over the sensor node area and broadcasts its current position periodically. A sensor node in the area computes its own location using the position of the mobile anchor node where the maximum RSSI is received by the sensor node. In our scheme, neither extra hardware on each sensor node nor communications between sensor nodes is needed. Our proposed scheme is simulated in Opnet and simulation results show that our scheme performs better than other range-free localization algorithms using mobile beacon nodes.
Neural Networks, 2008. IJCNN 2008. (IEEE World Congress on Computational Intelligence). IEEE International Joint Conference on; 07/2008
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ABSTRACT: Wireless sensor networks with many inexpensive sensor nodes allow users to accurately monitor a remote environment. Usually one or several mobile nodes are used to collect and combine sensor data from each individual stationary node. These networks require robust wireless communication protocols that are energy efficient and provide low latency. Motivated by these applications, we develop a novel medium access control (MAC) protocol for this kind of applications. The sensor nodes are expected to remain inactive for most of time, but become active when a mobile node is nearby. A few techniques for energy saving are developed in our protocol, e.g., true-sleep and pseudo-sleep modes are introduced to reduce energy consumption. They are implemented by radio-triggered circuit which wakes up the stationary nodes as a mobile node moves into the stationary nodespsila reception range. The proposed protocol is simulated in OPNET Modeler 10.5. The simulation results show that the proposed protocol has better performance than S-MAC and EAR (Eavesdrop-And-Register) in terms of latency, energy efficiency, and throughput.
Neural Networks, 2008. IJCNN 2008. (IEEE World Congress on Computational Intelligence). IEEE International Joint Conference on; 07/2008
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ABSTRACT: Wireless sensor networks (WSNs) are vulnerable to various attacks since they are distributed in unattended environments and have limited energy, storage and computation abilities. Preventive approaches can be applied to protect WSNs from some kinds of attacks. However, preventive methods are not efficient on specific attacks. So it is necessary to develop some mechanisms for intrusion detection. Intrusion detection system (IDS) not only prevents adversaries from attacking the network, but also provides attackspsila features for improving the preventive algorithms. The traditional intrusion detection algorithms canpsilat be applied directly to WSNs due to their constraints of resources. According to the problems in the current intrusion detection systems, based on immunology, we propose a novel IDS which is distributed, robust, and adaptive. The simulation results indicate that the proposed IDS has high accuracy in attack detections.
Neural Networks, 2008. IJCNN 2008. (IEEE World Congress on Computational Intelligence). IEEE International Joint Conference on; 07/2008
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ABSTRACT: A novel SON (silicon-on-nothing)-LDMOS (laterally diffused MOS) with heavily doped buried layer (HDBL) beneath air layer is proposed for RF base-station power amplifier application. The characteristics of the proposed device are analyzed in terms of breakdown voltage, kink effect, and high frequency performance. With the device and circuit simulator Atlas, two-dimensional simulations are presented to investigate the vertical and lateral breakdown voltages and parasitic capacitance characteristics of the proposed device. The simulation results show that high breakdown voltage and low parasitic output capacitance can be attained. The breakdown voltage of the proposed device is four times that of the conventional SOI (silicon-on-insulator) device. In addition, the kink effect and self-heating effect is suppressed dramatically. Our proposed device is fully compatible with commercial SON process, without complex field plate process. It can be used in the future design of high voltage RF power amplifiers.
Circuits and Systems for Communications, 2008. ICCSC 2008. 4th IEEE International Conference on; 06/2008
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ABSTRACT: Wireless sensor networks (WSN) are composed of a large number of sensor nodes which are normally battery powered. Since these nodes are often deployed in hazard environments, it is very difficult to change or recharge batteries. Some nodes' batteries may deplete faster than others because they undertake more transmission and reception tasks. Some of the depleted nodes may play a critical role in network connectivity, whose removal will separate the network into two or more pieces. Sub-networks disconnected to sink nodes can't send data to a base station any more. In this paper, we propose a distributed algorithm to prevent this crisis happening. In our algorithm, each node has the information of its neighbors and can predict whether it is a critical node. Once it identifies itself as a critical node, it triggers the network reconnection algorithm. S-MAC is a contention-based MAC protocol explicitly designed for sensor networks and we integrate our algorithm onto S-MAC. Our algorithm is simulated and the simulation results show that it works well for connectivity maintenance in wireless sensor networks.
Robotics and Biomimetics, 2007. ROBIO 2007. IEEE International Conference on; 01/2008
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ABSTRACT: Radiofrequency identification (RFID) raises significant privacy concerns as it allows automated identification possibly without knowledge or permission of the tag bearer. Traditional cryptographic operations, such as authentication and encryption, to prevent unauthorized read are too costly for RFID tags to be deployed into cost-sensitive applications, e.g., into item-level applications in supply chains. This paper addresses the privacy issues and demonstrates a solution which achieves high security while maintains low manufacturing and management cost. The RFID tags carry only ID numbers which are disguised in response through randomization and a hash function to avoid clandestine tracking. The response of ID numbers is divided into segments to reduce database computational complexity. The database stores and maintains the inventory information to avoid clandestine inventorying. Also, the burden of cryptographic operations shifts from tags to database, tags will thus be cheap to manufacture and manage.
Integration Technology, 2007. ICIT '07. IEEE International Conference on; 04/2007
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ABSTRACT: Silicon-on-Nothing (SON) device is expected to be obtained by double He<sup>+</sup> implantation. The leakage currents of the SON MOSFET using twice energy implants are lower for 1~2 order of magnitude than that of using single energy implant simulated by ATLAS Simulator on electrical characteristic of SON MOSFETs. The self-heating effect in SON device can be suppressed by etch-back sidewall of shallow trench insulation (STI). A theoretical simulation is proposed to calculate the ion implantation distribution precisely.
Integration Technology, 2007. ICIT '07. IEEE International Conference on; 04/2007
