distributed file-systems are a popular storage abstraction for cloud-computingapplications. they provide generic data access for different applications in order to pass information between computing nodes and to save...
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distributed file-systems are a popular storage abstraction for cloud-computingapplications. they provide generic data access for different applications in order to pass information between computing nodes and to save computation results persistently. the performance of distributedapplications depends on data-consistency protocols and meta-data management, but these factors of influence are often statically configured in distributed file-systems. In this paper, we describe EFS, an in-memory file-system that manages meta-data and consistency by flexibly adapting to file-access patterns.
Although there are several works on providing event-based services in pervasive environment or WSN, most of them have not considered composite event detection in an energy-efficient fashion. Composite events consist o...
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ISBN:
(纸本)9781457705137
Although there are several works on providing event-based services in pervasive environment or WSN, most of them have not considered composite event detection in an energy-efficient fashion. Composite events consist of multiple primitive events with temporal and spatial relations and are much more difficult to manage. Because of the resource constraints in WSN, existing event detection algorithms may not be suitable for WSN when energy efficiency is considered. In this paper, we propose TED (Type-based composite Event Detection), a distributed composite event detection algorithm. the essential idea of TED is type-based event fusion, where some sensor nodes are selected as fusion points. then lower-level events will be fused on these fusion points for detection of higher-level composite events. Each composite event type is assigned to certain fusion point for detection so that the composite events may be detected in-network instead of at the sink. Event fusion with minimum energy cost is an NP-complete problem. We propose a distributed randomized algorithm to solve the problem. We analyze the energy efficiency of TED to show both its effectiveness and efficiency. By carrying out both simulation and real world experiments on TED, we show that TED can reduce the energy cost by 10-20% in event-based WSN applications compared with naive event detection mechanism where the event relations are not considered.
parallelcomputing environment may be useful for faster and real time shape transformation generation. However, it is difficult to parallelised most of the existing shape transformation algorithms. In this paper, we d...
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ISBN:
(纸本)9789604742776
parallelcomputing environment may be useful for faster and real time shape transformation generation. However, it is difficult to parallelised most of the existing shape transformation algorithms. In this paper, we describe parallelisation of a particular shape transformation algorithm based on the basic shape transformation algorithm. "Master-Slave" model is adopted in parallelising the method with one master node and several slave nodes. Initially, one processor each is assigned to source and target data and slicing of both source and target data takes place until the desired number of steps has been reached. parallelisation is also incorporated in the next step which is the interpolation phase and then also in surface reconstruction phase. We have shown that the proposed parallel version of the shape transformation algorithm is 'embarrassingly parallel'. the ease of implementing this parallel approach has also been compared to similar efforts in other shape transformation algorithms.
A new secret-sharing-based e-auction scheme is proposed. distributed bid opening is employed to protect bid privacy. It can achieve all the desired properties for sealed-bid auctions at a reasonable cost. Moreover, at...
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A new secret-sharing-based e-auction scheme is proposed. distributed bid opening is employed to protect bid privacy. It can achieve all the desired properties for sealed-bid auctions at a reasonable cost. Moreover, attacks existing in the current secret-sharing-based sealed-bid e-auction schemes are prevented in the new scheme. In addition, it does not need any trust assumption.
Currently, there are a number of communication middleware technologiesthat are successful solutions to provide an abstraction for distributedcomputing in different domains. Although most current middlewares offer di...
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ISBN:
(纸本)9783642213380
Currently, there are a number of communication middleware technologiesthat are successful solutions to provide an abstraction for distributedcomputing in different domains. Although most current middlewares offer different interfaces for a number of programming languages, they are usually bound to use one specific communication paradigm. the usage of middleware decreases programming complexity, but it is not cost-free and fully transparent. Every distributed application using a communication middleware has some degree of dependence over the specific middleware it uses mainly related to the interaction paradigm of the communication. therefore, there is no fully transparent way to use middleware at present. this paper contributes to increase the transparency between applications and middlewares by presenting a common bridge that has been architected in an environment that requires using different middleware technologies interchangeably. this bridge is a software component to abstract the complexity of the middleware solutions requiring minimum porting efforts. Some results are presented to validate the transparency.
the two most recent PVSS (publicly verifiable secret sharing) schemes are illustrated to be vulnerable to a simple attack. Moreover, one of them has to deteriorate its efficiency greatly to meet practical security req...
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the two most recent PVSS (publicly verifiable secret sharing) schemes are illustrated to be vulnerable to a simple attack. Moreover, one of them has to deteriorate its efficiency greatly to meet practical security requirement. the attack makes the share holders to receive incorrect shares, which will lead secret reconstruction to mistake. the efficiency deterioration is so serious that no practical application can tolerate it. So the two most recent PVSS schemes actually cannot work reliably and efficiently as they claim.
the oil and gas industries have been great consumers of parallel and distributedcomputing systems, by frequently running technical applications with intensive processing of terabytes of data. By the emergence of clou...
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the oil and gas industries have been great consumers of parallel and distributedcomputing systems, by frequently running technical applications with intensive processing of terabytes of data. By the emergence of cloud computing which gives the opportunity to hire high-throughput computing resources with lower operational costs, such industries have started to adopt their technical applications to be executed on such high-performance commodity systems. In this paper, we first give an overview of forward/inverse Prestack Kirchhoff Time Migration (PKTM) algorithm, as one of the well-known seismic imaging algorithms. then we will explain our proposed approach to fit this algorithm for running on Google's MapReduce framework. Toward the end, we will analyse the relation between MapReduce-based PKTM completion time and the number of mappers/reducers on pseudo-distributed MapReduce mode.
Self organizing maps (also called Kohonen maps) are known for their capability of projecting high-dimensional space into lower dimensions. there are commonly discussed problems like rapidly increased computational com...
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ISBN:
(纸本)9783642272448
Self organizing maps (also called Kohonen maps) are known for their capability of projecting high-dimensional space into lower dimensions. there are commonly discussed problems like rapidly increased computational complexity or specific similarity representation in the high-dimensional space. In the paper there is proposed the effective clustering algorithm based on self organizing map withthe main purpose to reduce high dimension of the input dataset. the problem of computational complexity is solved using parallelization;the speed of proposed algorithm is accelerated using the algorithm version suitable for data collections with certain level of sparsity.
Position information is vital for wireless sensor networks in many applications. In this paper, based on the barycentric coordinate system, we incorporate a term constrains sensors to remain the intrinsic structure re...
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Position information is vital for wireless sensor networks in many applications. In this paper, based on the barycentric coordinate system, we incorporate a term constrains sensors to remain the intrinsic structure revealed by range measurements between neighboring nodes into the STRESS function, which is the cost function optimized by the distributed weighted-multidimensional scaling algorithm (dwMDS). By minimizing the modified cost function, we derive a distributed localization algorithm called the Multidimensional Scaling and Barycentric Coordinates based distributed Localization Algorithm (MDS_BC_DLA). Experimental results on four different types of WSNs show MDS_BC_DLA outperforms dwMDS.
In order to improve system performance, many modern processors support superpage technology, which is also called variable page. It improves TLB coverage greatly without increasing TLB size. But supporting superpage b...
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