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Directional antenna offers various benefits for wireless sensor networks, such as increased spatial reuse ratio and reduced energy consumption. Numerous localization schemes using anchor nodes equipped with omni-directional antenna to transmit beacon information have been proposed. However, the radiated RF signal from an omni-directional antenna is easier(More)
Recently, with the explosive increase of automobiles in China, people park their cars on streets without following the rules and police has hard time to conduct law enforcement without introducing effective street parking system. To solve the problem, we propose a SPS (street parking system) based on wireless sensor networks. For accurately detecting a(More)
Many localization algorithms have been proposed for wireless sensor network. They focus on localization for static sensor network, but not for mobile one. With the development of sensor and network technology, a wireless sensor network with mobile sensor nodes becomes applicable. A mobile wireless sensor network (MWSN) consists of sensor nodes that may move(More)
Directed diffusion is a classic data-centric routing protocol in Wireless Sensor Networks (WSNs). In directed diffusion based WSNs, data generated by sensor nodes is named by attribute-value pairs. A sink requests data by sending interests. The data that match the interests are then "drawn" down towards the sink. Intermediate nodes cache or transform data,(More)
Although the possibility of attacking elliptic curve cryptosystems (ECC) by power analysis repeatedly appears in research papers, there were few electromagnetic analysis papers and conclusive experiments where actual elliptic curve cryptosystems were successfully attacked and prevented. In this paper we describe electromagnetic (EM) analysis experiments(More)
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(More)
Wireless sensor networks (WSNs) are a large ad hoc networks of distributed sensors that are equipped with low power supply modules. Location information is a basic requirement for many WSNs applications. Because localization accuracy is sufficient for many sensor network applications, range free localization schemes based on RSSI technique are being pursed(More)
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.(More)
—Two-way cooperative communications are considered to improve the throughput of conventional one-way cooperative communications. For fast Rayleigh fading channels, we propose optimal and suboptimal non-coherent detectors for on-off keying (OOK) and frequency-shift keying (FSK) modulated two-way amplify-and-forward (AF) cooperative communications in this(More)