The processing of a join query in a distributed environment exacts the usage of both the network and its computational facilities. A formulation that accounts for both, and felicitously constructed as an integer linea...
详细信息
The processing of a join query in a distributed environment exacts the usage of both the network and its computational facilities. A formulation that accounts for both, and felicitously constructed as an integer linear program, is proposed. Information disseminated among the sites of a distributed system is to be amalgamated and presented to a user, in response to his request. From all possible strategies by which this might be achieved, one necessitating the smallest usage of system resources is to be chosen. The data transferal resources of the network are usually presumed to be of greatest significance, and therefore, an optimal strategy is most often defined to be one which minimizes the total transmission cost. One model conforming to this philosophy, appearing in [1), expediently takes the form of a linear integer program, and so forms the basis for further refinement. In the omission of processing costs, the various processor elements of the network are treated homologously;dissimilarities in processing ability are also ignored. By analyzing the nature of join computations at a single processor, the minimal transmission cost model can be hybridized to incorporate the cost of such computations and differences in processing power.
The uncertainty inherent in the distributed environment poses new challenges to the efficient utilization of system resources in managing database transactions. In response to this realization, the execution of a join...
详细信息
The uncertainty inherent in the distributed environment poses new challenges to the efficient utilization of system resources in managing database transactions. In response to this realization, the execution of a join query in a system with probabilistic resource and cost parameters is contemplated, leading to the development of stochastic programming models. Information in the form of relational tables and scattered amongst the sites of a distributed database system is to be collated and presented to the appropriate user, in response to an issued request. Performing this task demands the usage of limited resources;the ultimate goal is the determination of an execution strategy incurring minimal cost to the system. The actual state of any network component at the moment of its exploitation cannot be exactly ascertained in advance. Any interrogation of a distant element must be communicated by the network, and this involves a delay, as perceived by the questioner, during which the state of the system may change. Indeed, the time at which a task assigned to any particular component cannot itself be precisely predicted, even if the future state of the component could be known definitively. By considering the uncertain nature of the distributed environment, the earlier model of join query evaluation presented in [1] can be modified in different ways to account for system parameters known only in a stochastic sense. This new level of subjectivity is a revelation of the many different attitudes that may be taken towards the chance of infeasibility in the solution, for the major issue in dealing with uncertainty is the choice of an appropriate measure of risk.
In a heterogeneous wireless network (HWN), traffic is distributed primarily by grouping and channelling identical traffic through a particular access point. In this paper, we introduce an effective traffic load balanc...
详细信息
A novel framework for parallel subgraph isomorphism on GPUs is proposed, named GPUSI, which consists of GPU region exploration and GPU subgraph matching. The GPUSI iteratively enumerates subgraph instances and solves ...
详细信息
A novel framework for parallel subgraph isomorphism on GPUs is proposed, named GPUSI, which consists of GPU region exploration and GPU subgraph matching. The GPUSI iteratively enumerates subgraph instances and solves the subgraph isomorphism in a divide-and-conquer fashion. The framework completely relies on the graph traversal, and avoids the explicit join operation. Moreover, in order to improve its performance, a task-queue based method and the virtual-CSR graph structure are used to balance the workload among warps, and warp-centric programming model is used to balance the workload among threads in a warp. The prototype of GPUSI is implemented, and comprehensive experiments of various graph isomorphism operations are carried on diverse large graphs. The experiments clearly demonstrate that GPUSI has good scalability and can achieve speed-up of 1.4–2.6 compared to the state-of-the-art solutions.
It is proposed that the execution of a chain query in a distributed system can be usefully and appropriately modeled as an integer linear program. In response to a user request, information in the form of relational t...
详细信息
It is proposed that the execution of a chain query in a distributed system can be usefully and appropriately modeled as an integer linear program. In response to a user request, information in the form of relational tables scattered across the network is to be combined and made available to the user. The formulation initially attained by considering the behavior of the distributed system in processing such a query is then reduced by removing redundant linear constraints, to produce a model of minimal transmission cost execution. In view of varying properties displayed by the possibly many optima of this problem, further attention is devoted to discriminating between them. By perturbing the objective function, those solutions requiring fewer network transmissions can be favored at the expense of equal-cost, but more complicated, strategies. This includes those strategies that may specify the transmission of a relation around a cycle;when the costs of transmission between sites forming the cycle are zero, such a solution might otherwise be optimal. Many different ways have been devised to solve programs having some number of variables restricted to taking only integer values in some interval, and virtually any of these might be used to solve the join query model. One possible method, using a tree-search approach, is discussed here.
This paper presents an approach to the specification of external interfaces of an electronic broker used in the Architecture for Electronic Brokerage Systems (AEBS). The external interface specified by the AEBS archit...
详细信息
The scale of global data center market has been explosive in recent years. As the market grows, the demand for fast provisioning of the virtual resources to support elas- tic, manageable, and economical computing over...
详细信息
The scale of global data center market has been explosive in recent years. As the market grows, the demand for fast provisioning of the virtual resources to support elas- tic, manageable, and economical computing over the cloud becomes high. Fast provisioning of large-scale virtual ma- chines （VMs）, in particular, is critical to guarantee quality of service （QoS）. In this paper, we systematically review the existing VM provisioning schemes and classify them in three main categories. We discuss the features and research status of each category, and introduce two recent solutions, VMThunder and VMThunder＋, both of which can provision hundreds of VMs in seconds.
Many real-world networks are found to be scale-free. However, graph partition technology, as a technology capable of parallel computing, performs poorly when scale-free graphs are provided. The reason for this is that...
详细信息
Many real-world networks are found to be scale-free. However, graph partition technology, as a technology capable of parallel computing, performs poorly when scale-free graphs are provided. The reason for this is that traditional partitioning algorithms are designed for random networks and regular networks, rather than for scale-free networks. Multilevel graph-partitioning algorithms are currently considered to be the state of the art and are used extensively. In this paper, we analyse the reasons why traditional multilevel graph-partitioning algorithms perform poorly and present a new multilevel graph-partitioning paradigm, top down partitioning, which derives its name from the comparison with the traditional bottom-up partitioning. A new multilevel partitioning algorithm, named betweenness-based partitioning algorithm, is also presented as an implementation of top-down partitioning paradigm. An experimental evaluation of seven different real-world scale-free networks shows that the betweenness-based partitioning algorithm significantly outperforms the existing state-of-the-art approaches.
Resource management for individual flows can significantly improve quality of service (QoS) in mobile cellular networks. However, its efficiency depends on the availability of information about the movement of mobile ...
详细信息
ISBN:
(纸本)0780382773
Resource management for individual flows can significantly improve quality of service (QoS) in mobile cellular networks. However, its efficiency depends on the availability of information about the movement of mobile terminals. Movement prediction can potentially provide this information, but is costly if performed by the network and usually assumes a certain movement model, which may not adequately reflect each individual user's behavior. Instead, we propose the concept of movement contracts, where a mobile terminal specifies its movement to the network, which in return provides a better QoS as long as the provided specification is sufficiently accurate. We describe approaches to specify the spatial and temporal aspects of movement with a parsimonious parameter set and evaluate these approaches through simulations. We find that movement contracts can significantly reduce both session blocking and handover dropping probability simultaneously, whereas existing approaches have to make a tradeoff between these.
Privacy is an essential topic in (social) robotics and becomes even more important when considering interactive and autonomous robots within the domestic environment. Robots will collect a lot of personal and sensitiv...
详细信息
暂无评论