Effective Cache based Policies in Wireless Sensor Networks: A Survey <s> INTRODUCTION <s> Advances in microelectronics, array processing, and wireless networking have motivated the analysis and design of low-cost integrated sensing, computing, and communicating nodes capable of performing various demanding collaborative space–time processing tasks. In this paper, we consider the problem of coherent acoustic sensor array processing and localization on distributed wireless sensor networks. We first introduce some basic concepts of beamforming and localization for wide-band acoustic sources. A review of various known localization algorithms based on time-delay followed by least-squares estimations as well as the maximum–likelihood method is given. Issues related to practical implementation of coherent array processing, including the need for fine-grain time synchronization, are discussed. Then we describe the implementation of a Linux-based wireless networked acoustic sensor array testbed, utilizing commercially available iPAQs with built-in microphones, codecs, and microprocessors, plus wireless Ethernet cards, to perform acoustic source localization. Various field-measured results using two localization algorithms show the effectiveness of the proposed testbed. An extensive list of references related to this work is also included. <s> BIB001 </s> Effective Cache based Policies in Wireless Sensor Networks: A Survey <s> INTRODUCTION <s> Estimating the number of people in a crowded environment is a central task in civilian surveillance. Most vision-based counting techniques depend on detecting individuals in order to count, an unrealistic proposition in crowded settings. We propose an alternative approach that directly estimates the number of people. In our system, groups of image sensors segment foreground objects from the background, aggregate the resulting silhouettes over a network, and compute a planar projection of the scene's visual hull. We introduce a geometric algorithm that calculates bounds on the number of persons in each region of the projection, after phantom regions have been eliminated. The computational requirements scale well with the number of sensors and the number of people, and only limited amounts of data are transmitted over the network. Because of these properties, our system runs in real-time and can be deployed as an untethered wireless sensor network. We describe the major components of our system, and report preliminary experiments with our first prototype implementation. <s> BIB002 </s> Effective Cache based Policies in Wireless Sensor Networks: A Survey <s> INTRODUCTION <s> One major duty for fire or law enforcement agencies is to respond rapidly to emergency services, crime scenes, and disasters. In many cases, they have to face life-threatening conditions for locating evidence, conducting investigation, or rescuing innocent civilians in an unfamiliar, unstable, and dangerous environment. We propose to develop a system based on the following considerations. 1) Sensors such as tracker and cameras are scattered along the area for capturing subjects' location and monitoring events. Those sensors being coordinated via wireless communication can make an intimate connection to the immediate environment and react to events in a remote area instantly. 2) Network and sensors act in a cooperative and adaptive manner to acquire information and send it back to centralized control center for data fusion and decision-making. Therefore, the sensor control can be updated and field of view (FOV) from each camera can be optimized. 3) Central control embedded with automated scene analysis and subject behavior detection interprets video camera signals constantly and informs agencies when certain events are detected. <s> BIB003 </s> Effective Cache based Policies in Wireless Sensor Networks: A Survey <s> INTRODUCTION <s> We present Telos, an ultra low power wireless sensor module ("mote") for research and experimentation. Telos is the latest in a line of motes developed by UC Berkeley to enable wireless sensor network (WSN) research. It is a new mote design built from scratch based on experiences with previous mote generations. Telos' new design consists of three major goals to enable experimentation: minimal power consumption, easy to use, and increased software and hardware robustness. We discuss how hardware components are selected and integrated in order to achieve these goals. Using a Texas Instruments MSP430 microcontroller, Chipcon IEEE 802.15.4-compliant radio, and USB, Telos' power profile is almost one-tenth the consumption of previous mote platforms while providing greater performance and throughput. It eliminates programming and support boards, while enabling experimentation with WSNs in both lab, testbed, and deployment settings. <s> BIB004 </s> Effective Cache based Policies in Wireless Sensor Networks: A Survey <s> INTRODUCTION <s> The Intel mote is a new sensor node platform motivated by several design goals: increased CPU performance, improved radio bandwidth and reliability, and the usage of commercial off-the-shelf components in order to maintain cost-effectiveness. This new platform is built around an integrated wireless microcontroller consisting of an ARM*7 core, a Bluetooth radio, SRAM and FLASH memory, as well as various I/O options. The Intel Mote software architecture is based on an ARM port of TinyOS. Networking and routing layers have been created on top of the TinyOS base to provide Bluetooth-based multi-hop functionality. The network is self-organizing on startup and has mechanisms to repair failed links and circumvent failed nodes. A reliable high bandwidth streaming transport layer has also been created. The Intel Mote was deployed in an equipment monitoring application using industrial vibration sensors. This application was chosen since it benefits from the increased platform capabilities and network bandwidth of the Intel Mote platform. The paper presents a detailed analysis of the observed network operation, packet transfer rates, and power consumption. <s> BIB005 </s> Effective Cache based Policies in Wireless Sensor Networks: A Survey <s> INTRODUCTION <s> With the advance of processor technology, critical device parameters are significantly affected by the process variation. Subsequently, these critical parameters result in high access latencies, significant leakage power and abnormal high temperature. Cache memory circuits are easily affected by the process variation than any other hardware components; due to the densely tied transistors. Moreover, the process variation decreases both the yield of the chip and the lifetime of cache memory used in resource limited devices. Cache memory used in resource limited devices may get affected easily by the process variation due to hostile environments.In this paper, we introduce a simple but very effective process variation tolerant technique using the conventional cache replacement policies. This technique selects the cache block replacement victims excluding the affected cache block by the process variation. Without additional hardware components, the proposed technique can handle the affected cache block minimizing the performance loss. Our experiments show that when we adopted our proposed idea, the performance penalty is less than 1% in case of 12.5% cache blocks cannot be used. Under the severe process variation, our proposed idea deteriorates the performance by only about 2%. By applying our technique in cache memory of resource limited devices, sensor nodes used in sensor networks will be more reliable. <s> BIB006 </s> Effective Cache based Policies in Wireless Sensor Networks: A Survey <s> INTRODUCTION <s> When ring components 4 of layers to assemble a laminated ring 3 are unloaded from a component storage facility 10, a computer 13 generates lamination combinatorial data representing a combination of ring components of layers. A target frequency distribution of circumferential length values of ring components 4 of each layer is established, and lamination combinatorial data including ring components of a class where an error of an actual inventory frequency with respect to a target frequency is large are selected in a layer where an error between the target frequency distribution and an actual inventory frequency distribution is maximum. Ring components 4 of all layers corresponding to the selected lamination combinatorial data are unloaded from the component storage facility 10. A distribution of size data of the ring components 4 of each layer in the component storage facility 10 is thus continuously maintained in a state capable of assembling more laminated rings 4, and the stable mass-productivity of laminated rings 3 is continuously achieved. <s> BIB007
The recent developments in making energy efficient Wireless Sensor Network BIB001 BIB004 is giving new direction to deploy these networks in applications like surveillance BIB003   , industrial monitoring BIB005 , traffic monitoring  , habitat monitoring  , cropping monitoring BIB007 , crowd counting BIB002 , etc . The growing use of these networks is making engineers to evolve innovative and efficient ideas in this field. A lot of research in data routing, data compression and in-network aggregation has been proposed in recent years. One of the major factors that could help in building an efficient Wireless Sensor Network is by the use of caching. To best of our knowledge, few research has been done in making an energy efficient Wireless Sensor Network utilizing the benefits of caching the data. Caching is a technique which provides faster data access in any computing system. With the discovery of cache the accessibility of data has been increased as it stores data to be needed in future and can be retrieved rapidly. Caching BIB006 has made its impact in the Wireless sensor networks also. A wireless sensor network consists of a large number of nodes  spread over a specific area where we want to look after at the changes going on there. A sensor node generally consists of sensors, actuators, memory, a processor and they do have communication ability. All the sensor nodes are allowed to communicate through a wireless medium. The wireless medium may either of radio frequencies, infrared or any other medium, of course, having no wired connection. These nodes are deployed in a random fashion and communicate within to make an ad-hoc network. If the node is not able to communicate with other through direct link, i.e. they are out of coverage range of each other, the data can be send to the other node by using the nodes in between them. This property refers to multi-hoping. Generally WSNs are not centralized one as there is peer-topeer communication between the nodes. So there is no requirement of prior established infrastructure to deploy the network. WSN gives flexibility of adding nodes and removing the nodes as required. But this gives rise to many drastic changes to deal with in the network topology such as updating the path, or the network tree, etc. In a WSN the node that gathers the data information refers to sink. The sink may be connected to the outside world through internet where the information can be utilized within time constraints.