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Active period Sleep period Active period Sleep period SYNC usage DATA usage time Fig. 1. Sleep-awake cycles of SMAC. Abstract— SMAC is a popular duty-cycled MAC protocol, designed for wireless sensor networks to save energy and prolong the network lifetime. However, existing work evaluates the performance of SMAC solely through simulations or field(More)
— IEEE 802.16 networks are going to provide broadband wireless access with quality of service (QoS) guarantee. In all of services, real-time video traffic plays an impeditive role because of its varying bit-rate and stringent delay constraint. To the best of our knowledge, no call admission control (CAC) and scheduling schemes cover throughput expectation,(More)
Wireless sensor networks are often battery-powered, and hence extending the network lifetime is one of the primary concerns in the ubiquitous deployment of wireless sensor networks. One approach to efficiently utilize the limited energy supplies of the sensors is to have the medium access control (MAC) protocol duty-cycle the sensors, periodically putting(More)
—In wireless sensor networks, multipath routing is used to alleviate reliability degradation due to multihop transmissions over error-prone wireless channels. However, multipath routing is not energy-efficient, as it requires all the nodes in the network to always be awake. To prolong the network lifetime while maintaining a certain reliability performance,(More)
Various applications of wireless sensor networks require multihop data transmission over error-prone wireless links, hence multipath routing can be used to meet the application's reliability requirement. On the other hand, wireless sensors are usually battery powered, and thus it is very important to save energy in order to prolong the network lifetime. In(More)
Sensor sleeping is a widely-used and cost-effective technique to save energy in wireless sensor networks. Protocols at different stack levels can, either individually or simultaneously, make the sensor sleep so as to extend the application lifetime. To determine the best choice for sensor sleeping under different network conditions and application(More)
The functional integrity of endothelial cells is a marker and a prerequisite for vascular health. It is well established that the endothelium not only modulates, but also mediates vascular disease processes. Certain diseases such as diabetes, dyslipidaemia, obesity, and arterial hypertension advance endothelial injury. The disease process induces cellular(More)
Single-hop centralized wireless sensor networks are widely used for applications ranging from security and surveillance to medical monitoring. Often the goal of these networks is to provide satisfactory quality of service (QoS) to the application under different system states, but it is difficult to determine how the appropriate sensor sets should be(More)
I. INTRODUCTION As wireless sensor networks gain increasing prominence for a variety of practical applications, design challenges arise due to the sensors' limited energy supplies and due to the application-specific quality of service (QoS) requirements. Since sensors are usually battery-operated, and may not be rechargeable, protocol designers must look(More)