oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
An Approach to Ad hoc Cloud Computing  [PDF]
Graham Kirby,Alan Dearle,Angus Macdonald,Alvaro Fernandes
Computer Science , 2010,
Abstract: We consider how underused computing resources within an enterprise may be harnessed to improve utilization and create an elastic computing infrastructure. Most current cloud provision involves a data center model, in which clusters of machines are dedicated to running cloud infrastructure software. We propose an additional model, the ad hoc cloud, in which infrastructure software is distributed over resources harvested from machines already in existence within an enterprise. In contrast to the data center cloud model, resource levels are not established a priori, nor are resources dedicated exclusively to the cloud while in use. A participating machine is not dedicated to the cloud, but has some other primary purpose such as running interactive processes for a particular user. We outline the major implementation challenges and one approach to tackling them.
Cognitive radio ad hoc networks (CRAHNs): Cognitive radio ad hoc networks (CRAHNs): Resource allocation techniques based on Bio-inspired computing  [PDF]
Santosh Kumar Singh
Computer Science , 2010,
Abstract: Spectrum is a scarce commodity, and considering the spectrum scarcity faced by the wireless-based service providers led to high congestion levels. Technical inefficiencies from pooled spectrum (this is nothing but the "common carrier principle" adopted in oil/gas/electricity pipelines/networks.), since all ad hoc networks share a common pool of channels, exhausting the available channels will force ad hoc networks to block the services. Researchers found that cognitive radio (CR) technology may resolve the spectrum scarcity. CR network proved to next generation wireless communication system that proposed as a way to reuse under-utilised spectrum of licensee user (primary network) in an opportunistic and non-interfering basis. A CR is a self-configuring entity in a wireless networking that senses its environment, tracks changes, and frequently exchanges information with their networks. Adding this layer of such intelligence to the ad hoc network by looking at the overall geography of the network known as cognitive radio ad hoc networks (CRAHNs). However, CRAHN facing challenges and condition become worst while tracks changes i.e. reallocation of another under-utilised channels while primary network user arrives. In this paper, channels or resource reallocation technique based on bio-inspired computing algorithm for CRAHN has been proposed.
A simple, adaptable and efficient heterogeneous multi-tenant database architecture for ad hoc cloud
Sanjeev Kumar Pippal and Dharmender Singh Kushwaha
Journal of Cloud Computing: Advances, Systems and Applications , 2013, DOI: 10.1186/2192-113X-2-5
Abstract: Data management and sharing is the challenge being faced by all the IT majors today. Adds over it, is the challenge faced by the cloud service providers in terms of multi-tenancy of data and its efficient retrieval. It becomes more complex in a heterogeneous computing environment to provide cloud services. A simple, robust, query efficient, scalable and space saving multi-tenant database architecture is proposed along with an ad hoc cloud architecture where organizations can collaborate to create a cloud, that doesnt harm their existence or profitability. An ad hoc cloud fits very well to the scenario where one wants to venture into remote areas for providing education services using a cloud. The results of the proposed multi-tenant database show 20% to 230% improvement for insertion, deletion and updation-queries. The response of the proposed approach is stable as compared to other system which degrades in terms of response time by 384% for increased number of attributes up to 50. The proposed approach is also space efficient by almost 86%. Dynamically changing cloud configurations requires adaptable database and mechanism to persist and manage data and exploit heterogeneous resources. The proposed ad hoc cloud handles heterogeneity of the involved nodes and deals with node specific granularity while decomposing workloads for efficient utilization of resources.
Approximation and Heuristic Algorithms for Computing Backbones in Asymmetric Ad-Hoc Networks  [PDF]
Faisal N. Abu-Khzam,Christine Markarian,Friedhelm Meyer auf der Heide,Michael Schubert
Computer Science , 2015,
Abstract: We consider the problem of dominating set-based virtual backbone used for routing in asymmetric wireless ad-hoc networks. These networks have non-uniform transmission ranges and are modeled using the well-established disk graphs. The corresponding graph theoretic problem seeks a strongly connected dominating-absorbent set of minimum cardinality in a digraph. A subset of nodes in a digraph is a strongly connected dominating-absorbent set if the subgraph induced by these nodes is strongly connected and each node in the graph is either in the set or has both an in-neighbor and an out-neighbor in it. Distributed algorithms for this problem are of practical significance due to the dynamic nature of ad-hoc networks. We present a first distributed approximation algorithm, with a constant approximation factor and O(Diam) running time, where Diam is the diameter of the graph. Moreover we present a simple heuristic algorithm and conduct an extensive simulation study showing that our heuristic outperforms previously known approaches for the problem.
Realization of Ad hoc network and analysis of performance
Linux环境下Ad hoc网络的实现及性能分析

WANG Hao,WEI Ming-lei,LI Yun,CHEN Qian-bin,LONG Ke-ping,
王浩
,魏明磊,李云,陈前斌,隆克平

重庆邮电大学学报(自然科学版) , 2005,
Abstract: 主要提出在Linux操作系统下实现Ad hoc网络的方案。在现有的可以用于Ad hoc网络的路由协议中选择动态源路由(DSR)作为实现协议,建成了由多个节点组成的运行DSR路由协议的试验网,在试验网上对Ad hoc网中的数据传输和语音会议进行了测试。最后对测得的数据进行了分析,并提出了改进方案。
A Distributed Secure Outsourcing Scheme for Solving Linear Algebraic Equations in Ad Hoc Clouds  [PDF]
Wenlong Shen,Bo Yin,Xianghui Cao,Yu Cheng
Computer Science , 2015,
Abstract: The emerging ad hoc clouds form a new cloud computing paradigm by leveraging untapped local computation and storage resources. An important application application over ad hoc clouds is outsourcing computationally intensive problems to nearby cloud agents to solve in a distributed manner. A risk with ad hoc clouds is however the potential cyber attacks, with the security and privacy in distributed outsourcing a significant challenging issue. In this paper, we consider distributed secure outsourcing of linear algebraic equations (LAE), one of the most frequently used mathematical tools, in ad hoc clouds. The outsourcing client assigns each agent a subproblem : all involved agents then apply a consensus based algorithm to obtain the correct solution in a distributed and iterative manner. We identify a number of security risks in this process, and propose a secure outsourcing scheme which can not only preserve privacy to shield the original LAE parameters and the final solution from the computing agents, but also detect misbehavior based on mutual verifications in a real-time manner. We rigorously prove that the proposed scheme converges to the correct solution of the LAE exponentially fast, has low computation complexity at each agent, and is robust against the identified security attacks. Extensive numerical results are presented to demonstrate the effectiveness of the proposed method.
Routing in Ad Hoc Wireless Networks using Soft Computing techniques and performance evaluation using Hypernet simulator  [PDF]
Siddesh.G.K,K.N.Muralidhar,Manjula.N.Harihar
International Journal of Soft Computing & Engineering , 2011,
Abstract: An ad-hoc network is a collection of wireless mobile hosts forming a temporary network without the aid of any established infrastructure or centralized administration. In such an environment, it may be necessary for one mobile host to enlist the aid of other hosts in forwarding a packet to its destination, due to the limited range of each mobile host’s wireless transmissions. Much effort has gone into mobile ad-hoc network (MANET) research over the past decade. Yet, even to day, mobile ad-hoc networking is seen as a relatively new area of research. The reason for this can be traced to the fact that the maturity in truly understanding these networks is still alarmingly low and actual deployment of these networks rare. This paper presents a protocol for routing in ad hoc networks that uses soft computing techniques like neural networks, fuzzy logic and genetic algorithm. The simulation has been performed using hyper net simulator for various existing protocols like proactive routing , reactive routing, power aware routing protocol, hybrid routing . Our protocol uses soft computing techniques protocol for establishing the link between the nodes in minimum time. The results of our experimentation have been very satisfactory and we have achieved the goal of optimal route finding to a large extent. The simulation results are obtained using hypernet simulator and are also compared with the results obtained using NS-2 .
A Non-anchored Unified Naming System for Ad Hoc Computing Environments  [PDF]
Yoo Chul Chung,Dongman Lee
Computer Science , 2006,
Abstract: A ubiquitous computing environment consists of many resources that need to be identified by users and applications. Users and developers require some way to identify resources by human readable names. In addition, ubiquitous computing environments impose additional requirements such as the ability to work well with ad hoc situations and the provision of names that depend on context. The Non-anchored Unified Naming (NUN) system was designed to satisfy these requirements. It is based on relative naming among resources and provides the ability to name arbitrary types of resources. By having resources themselves take part in naming, resources are able to able contribute their specialized knowledge into the name resolution process, making context-dependent mapping of names to resources possible. The ease of which new resource types can be added makes it simple to incorporate new types of contextual information within names. In this paper, we describe the naming system and evaluate its use.
Realization of different diversity technique for mimo based mobile ad-hoc network using space time block codes  [cached]
Swati Chowdhuri,Nilanjan Byabartal,Dr. S.S. Choudhury,Dr. P.K. Banerjee
International Journal of Computers & Technology , 2013,
Abstract: With the fast progress of MIMO technology and its growing applications in the mobile ad hoc networks, it is important to develop a technique to enable more efficient MIMO implemented mobile ad hoc network. The simple, yet powerful concept of an bit error rate (BER) performance calculation with respect to bit energy to noise spectral density ratio (Eb/N0) of a typical transmit diversity scheme with various number of transmit and receiving antennas. Different diversity technique for mimo based mobile ad hoc network using space time block codes are demonstrated to show the superiority in performance of MIMO over single-antenna routing schemes, particularly at high SNR.
Are Clouds Ready to Accelerate Ad hoc Financial Simulations?  [PDF]
Blesson Varghese,Adam Barker
Computer Science , 2014,
Abstract: Applications employed in the financial services industry to capture and estimate a variety of risk metrics are underpinned by stochastic simulations which are data, memory and computationally intensive. Many of these simulations are routinely performed on production-based computing systems. Ad hoc simulations in addition to routine simulations are required to obtain up-to-date views of risk metrics. Such simulations are currently not performed as they cannot be accommodated on production clusters, which are typically over committed resources. Scalable, on-demand and pay-as-you go Virtual Machines (VMs) offered by the cloud are a potential platform to satisfy the data, memory and computational constraints of the simulation. However, "Are clouds ready to accelerate ad hoc financial simulations?" The research reported in this paper aims to experimentally verify this question by developing and deploying an important financial simulation, referred to as 'Aggregate Risk Analysis' on the cloud. Parallel techniques to improve efficiency and performance of the simulations are explored. Challenges such as accommodating large input data on limited memory VMs and rapidly processing data for real-time use are surmounted. The key result of this investigation is that Aggregate Risk Analysis can be accommodated on cloud VMs. Acceleration of up to 24x using multiple hardware accelerators over the implementation on a single accelerator, 6x over a multiple core implementation and approximately 60x over a baseline implementation was achieved on the cloud. However, computational time is wasted for every dollar spent on the cloud due to poor acceleration over multiple virtual cores. Interestingly, private VMs can offer better performance than public VMs on comparable underlying hardware.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.