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One critical issue in wireless sensor networks is how to gather sensed information in an energy-efficient way since the energy is a scarce resource in a sensor node. Cluster-based architecture is an effective architecture for data-gathering in wireless sensor networks. However, in a mobile environment, the dynamic topology poses the challenge to design an(More)
A smart-card based authentication scheme for telecare medicine information systems enables patients, doctors, nurses, health visitors and the medicine information systems to establish a secure communication platform through public networks. Zhu recently presented an improved authentication scheme in order to solve the weakness of the authentication scheme(More)
— Wireless sensor networks have attracted much research attention in recent years. One critical issue in wireless sensor networks is how to gather sensed information in an energy efficient way since the energy is limited in a sensor node. Many protocols have been proposed for data-gathering or communication between wireless sensor nodes. However, most of(More)
A wireless sensor network is a resource constraint network, in which all sensor nodes have limited resources. In order to save resources and energy, data must be aggregated, and avoid amounts of traffic in the network. The aim of data aggregation is that eliminates redundant data transmission and enhances the life time of energy in wireless sensor network.(More)
One important issue in wireless sensor networks is how to gather sensed information in an energy efficient way since the energy is a scarce resource in a sensor node. Many protocols have been proposed for data-gathering between wireless sensor nodes. However, most of these protocols work on static wireless sensor networks. In this paper, we provide(More)
— This paper aims to determine the optimal number of clusters in an observation area for a wireless sensor network. We demonstrate that this goal can be achieved by a cross-layer approach from both perspectives of the power efficiency in the medium access control (MAC) layer and the coverage performance in the physical (PHY) layer.
This study proposes a vision-based intelligent nighttime driver assistance and surveillance system (VIDASS system) implemented by a set of embedded software components and modules, and integrates these modules to accomplish a component-based system framework on an embedded heterogamous dual-core platform. Therefore, this study develops and implements(More)
The communication of a wireless sensor network can be eaves dropped quite easily due to its properties, thereby requiring a security mechanism. Adding a key management scheme on the wireless sensor network is a kind of solution. This paper proposes a method to enhance the security of the existing random key pre-distribution scheme, that is considered to be(More)
For the cognitive radio (CR) network, a fundamental issue is how to identify the spectrum opportunities. First, each CR node determines whether there exists transmission opportunities on unlicensed bands. If not, this node will find other opportunity on licensed bands. Thus, increasing the opportunities of concurrent transmissions in unlicensed bands can(More)