In previous work we showed that Collocated Wireless Access Points coupled with appropriate management of their non-overlapping channels could be used for building Scalable Wireless Video-On-Demand (SWVoD) systems with...
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ISBN:
(纸本)9781605587752
In previous work we showed that Collocated Wireless Access Points coupled with appropriate management of their non-overlapping channels could be used for building Scalable Wireless Video-On-Demand (SWVoD) systems within a limited covered area. In this paper, we introduce the Grid of collocated Access Points or simply GAPS, a novel approach that uses clusters of Collocated Access Points as the basic blocks to efficiently build SWVoD systems for a wider covered area. In GAPS, each basic block is responsible for a distinct part of the covered area and the amount of APs per block can be set either statically or dynamically depending on the client concentration pattern (CCP). We present in details the framework of GAPS and report simulated performance results that indicated that GAPS could significantly decrease the blocking rate of video requests in comparison with previous design based on fixed distribution of basic blocks. In addition, GAPS had the advantage of sustaining the lower blockage rate over larger covered areas. Also, we showed that the higher setup cost of dynamic grids was fully compensated by handling changes on CCP much better than the static scheme so that GAPS could generate a higher monthly net income according to our cost metric. Copyright 2009 ACM.
The last few years have seen considerable interest in the wireless networking research community in analyzing the connectivity of wireless ad-hoc networks formed by a set of nodes distributed in a two dimensional plan...
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ISBN:
(纸本)9781424458707
The last few years have seen considerable interest in the wireless networking research community in analyzing the connectivity of wireless ad-hoc networks formed by a set of nodes distributed in a two dimensional plane (deployment area) with a (i) uniform probability density function and (ii) uniform transmission range. Although several important and interesting results are known in this domain, most of the connectivity studies consider a fault-free scenario where all nodes are available for network formation and do not consider failures among nodes caused by one reason or another. In very few studies where faults are considered, they are usually considered to be random in nature, i.e., the probability of a node failing is independent of its location in the deployment area. However, such fault scenario is inadequate to capture many realistic situations where the faulty nodes are spatially correlated. This is particularly true in combat environment where an enemy bomb can destroy a subset of nodes confined to a region. In this paper we investigate the impact of region-based faults on the connectivity of wireless networks. Through analysis and simulation, we provide results relating the probability of a network being connected as transmission range and the size of fault-region are varied. If d min (G) denotes the minimum node degree of the network, we provide the analytical expression for P(d min (G) ¿ k), which represents the probability of the minimum node degree being at least k, for k = 1. Moreover, we compute P(¿(G) ¿ k), where ¿(G) represents the connectivity of the graph G formed by the distribution of nodes in the deployment area and examine the relationship between P(d min (G) ¿ k) and P(¿(G) ¿ k) when k = 1.
Background. Network and clustering analyses of microarray co-expression correlation data often require application of a threshold to discard small correlations, thus reducing computational demands and decreasing the n...
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The head direction (HD) cell system in the brain of mammals is thought to be part of the neural circuitry supporting their spatial navigation capabilities. In this paper we present a neuromorphic VLSI system that mimi...
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ISBN:
(纸本)9781424438273
The head direction (HD) cell system in the brain of mammals is thought to be part of the neural circuitry supporting their spatial navigation capabilities. In this paper we present a neuromorphic VLSI system that mimics the operation of the HD system. Relying on spiking neurons and attractor dynamics, this system can be used to represent and retain the current estimate of head orientation in the environment and integrate angular velocity to update this estimate. The presented system is a first step towards more general odometry systems that could be used for modeling biological navigation systems.
Parallel rendering algorithms usually suffer from high load imbalance during execution, due to the irregular nature of the datasets. In this paper, we propose a new load balancing scheme for tile-based parallel render...
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Parallel rendering algorithms usually suffer from high load imbalance during execution, due to the irregular nature of the datasets. In this paper, we propose a new load balancing scheme for tile-based parallel rendering that includes strategies for load estimation, tile decomposition and tile assignment. The load estimation strategy computes the rendering cost for each pixel, and uses it as a prediction for the next frame. The tile decomposition strategy adaptively divides the screen into tiles based on the computed costs, until an evenly tile partition is achieved. The tile assignment strategy distributes the tiles among rendering processors, based on a 2-optimal scheduling. Experimental results show that our scheme achieves significant performance gains by reducing the load imbalance when compared to the traditional tile subdivision and static random distribution schemes.
AAAI was pleased to present the AAAI-08 Workshop program, held Sunday and Monday, July 13-14, in Chicago, Illinois, USA. The program included the following 15 workshops: Advancements in POMDP Solvers;AI Education Work...
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In this paper, we propose an architecture, which we call GridRT, capable of dealing with the main features, such as shadows and reflections effects, of Ray Tracing used for rendering three-dimensional scenes. This arc...
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In this paper, we propose an architecture, which we call GridRT, capable of dealing with the main features, such as shadows and reflections effects, of Ray Tracing used for rendering three-dimensional scenes. This architecture achieves an efficient overall performance yet using a simple and compact massively parallel design. The design exploits the usage of Xilinx ® Floating Point Operator IP Core and the spatial data structure of Regular Grids.
Man as a social being, as a being in social relations, is in constant motion. Such mobility affects the social networks that Man builds throughout one's existence. Networks that can consist of dozens, hundreds or ...
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ISBN:
(纸本)9781424435340
Man as a social being, as a being in social relations, is in constant motion. Such mobility affects the social networks that Man builds throughout one's existence. Networks that can consist of dozens, hundreds or even thousands of other people, with various degrees of mobility. During the formation of such networks, problems can arise, such as elements that concentrate many relationships, very isolated individuals or peripheral members of a network, people who are the only link between two distinct groups, agglomerations of people in isolated points. This can cause a series of losses to the most important element that flows through social networks: knowledge. In scientific social networks, this assertion takes even more importance, mainly on account of the mobility of researchers and the excess of knowledge circulating in it, making it more vulnerable to the movements of Man. It is with the intent of solving this problem that our work seeks to achieve success, as it analyzes the scientific social networks based on the GCC tool detects the problems related to them, and suggests recommendations of relationships to users considered harmful to the flow of knowledge in the network. We call this process of social network balancing. For the evaluation of this work we conducted a comparison with several similar proposals, and developed a working prototype, which in turn was used to make our case studies.
Sources of alternative, clean and smart energies are a demand on our modern world. And as a design project, collaboration and knowledge management are elements that improve the work on multidisciplinary teams. This wo...
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ISBN:
(纸本)9781424435340
Sources of alternative, clean and smart energies are a demand on our modern world. And as a design project, collaboration and knowledge management are elements that improve the work on multidisciplinary teams. This work describes a collaborative project to construct a Brazilian solid oxide fuel cell, its problems and the solution created to enable a collaborative work on a national context.
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