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The energy efficiency is a substantial key design issues in such networks. An efficient routing protocol is critical to prolong the life of sensor nodes. This work presents a hierarchical multiple-choice routing path protocol (HMRP) for wireless sensor networks. According to HMRP, the wireless sensor network is initially constructed as a layered network. Based on the layered network, sensor nodes...
Sensing coverage is viewed as one of the critical measures of the performance offered by a sensor network. In previous studies, the sensing range of a node is generally assumed to be a determinate value in all directions. For most types of sensing signals emitted from a far field, the obstructions in the propagation path will induce an extra loss in the received signal power, and cause a large variation,...
Knowing available energy in each part of a wireless sensor networks (WSN) is undoubtedly essential information. A simple approach to achieve this would be for sensor nodes to periodically report to the sink node on their available energy. This approach is expensive however in terms of energy consumption. In this work we apply several sampling techniques for obtaining such information in WSNs. The...
Wireless sensor networks provide an alternative way of improving our environments, such as environment surveillance, hazard monitoring, and other customized environmental applications. Good coverage of service in a sensor network is an essential issue to ensure the service of quality. This paper studies the deployment of new sensor nodes so that the improvement of coverage is optimized. We propose...
With 250,000 NTD invested, 6 man power allocated, and 9 month time elapsed, we present BL-Live. The seemingly dumb, senseless BL Hall at National Taiwan University is transformed to an intelligent office building by a 30+ node sensor network. Two everyday services, Elevator Report and Smart Office, are implemented to better utilize the resources of the building and of the building residents. Our experience...
We propose a novel approach to design an asynchronous wakeup schedule (AWS) for the radio of the nodes in wireless sensor networks, in order to reduce the end-to-end latency with energy efficient data transmission. Each node is assigned a particular color and the process is repeated for grouping the nodes based on graph coloring of vertices. The wakeup schedule of a node's radio is fixed based on...
Energy assessment of MAC protocols for wireless sensor networks is generally based on the times of transmit, receive and sleep modes. The switching energy between two consecutive states is generally considered negligible with respect to them. Although such an assumption is valid for traditional wireless ad hoc networks, is this assumption valid also for low duty cycle wireless sensor networks? The...
A commonly desired feature of large-scale, multi-hop, wireless sensor networks (WSNs) is the ability to reconfigure them after deployment. This reconfiguration could be as simple as changing a single parameter or as complex as replacing the entire application. Several protocols have been proposed to enable reconfiguration in WSNs, most of which use version numbers to distinguish new configurations...
Sensor networks have attracted intensive interests due to its extendable capability. In this paper, we attempt to answer a fundamental but practical question: "how should we deploy these nodes?" In most current designs, sensors are randomly or uniformly distributed because of their simplicity. However, the node deployment has a great impact to the wireless systems. It in essential highlights...
In wireless sensor networks (WSNs), congestion occurs, for example, when nodes are densely distributed, and/or the application produces high flow rate near the sink due to the convergent nature of upstream traffic. Congestion may cause packet loss, which in turn lowers throughput and wastes energy. Therefore congestion in WSNs needs to be controlled for high energy-efficiency, to prolong system lifetime,...
A wireless sensor network has been designed and deployed to gather data from nodes deployed inside glaciers. This paper describes the solutions to power management, radio communications and other challenges faced in the system together with a discussion of the performance of the final system. 18 months of data have now been received, which provide an insight not only into the glacier's behaviour but...
In this paper, we consider user authentication (UA) for wireless sensor networks. UA is a fundamental issue in designing dependable and secure systems. Imagine that a wireless sensor network is deployed in an intelligent building, a hospital, or even a university campus, to allow legitimate users to send queries and retrieve the respective result at any of the sensor nodes. Importantly, the system...
As more and more innovative applications of wireless sensor networks emerge, the need for deploying heterogeneous sensors with different functionalities and capabilities rise rapidly. In this study, we consider a heterogeneous sensor network containing at least two types of sensors: powerful sensors and normal sensors. Powerful sensors have higher energy and computing capacities, and can communicate...
The location estimation is a fundamental and essential issue for wireless sensor networks( WSNs). In this paper, we assume that only a few sensor nodes (named as beacon nodes) get their locations by Global Positioning System (GPS) and the remaining nodes without GPS (named as normal nodes) need to estimate their own locations by gathering the nearby neighboring information. Existing works are either...
Wireless sensor networks (WSN) have affected various military and civilian applications. Target tracking is one of the top applications of WSNs. Efficient computation and energy dissipation are critical requirements for a WSN when used in target tracking. The goals are to maximize the network's lifetime while ensuring accuracy. Existing methods such as the LEACH-based algorithms suffer either complex...
An approach combining distributed detection with error-correcting codes has recently been proposed to design a fault-tolerant classification system in wireless sensor networks. The detection result of each sensor must be transmitted to a fusion center for making a final decision. The mis-classification probability using this approach is high when the transmission channel is highly noisy. This work...
Wireless communications and digital electronics have enabled the development of low-power, low-cost, multifunctional sensors. The functionality of sensor network mainly is the measurement collection. The previous proposed protocols mainly focus on broadcasting tree structure, but it may not be efficient in data gathering. In this paper, we propose novel tree architecture that is a dynamic, adjustable,...
Most applications of wireless sensor networks (WSNs) the sensors are deployed on unfavorable environment such as chemical reactor or battlefield that with high temperature, noise, and interference, could probably incur sensor nodes sense, compute, or communicate improperly. Those also raise error responds to the data collectors. In this paper, a fault estimation model is proposed and can be used to...
In wireless sensor networks, storage policy of sensed event affects the number of required control messages. If the number of control message can be reduced, the network lifetime can be increased because transmitting unnecessary control message requires extra energy consumption. In this paper, a local storage method with small control overhead is proposed for object tracking application in wireless...
Wireless sensor networks introduce a new way for us to interact with the physical environment. Since wireless sensor networks use radio frequency as the communication medium, chances for the information retrieved by unexpected people are becoming easier and easier. In wireless sensor networks the resources are limited; it seems that AES is a good solution for this communication problem. Beside, a...
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