In global computing applications the availability of a mechanism for some form of committed choice can be useful, and sometimes necessary. It can conveniently handle, e.g., distributed agreements and negotiations with nested choice points. We propose a linguistic extension of the Join calculus for programming nested commits, called Committed Join (cJoin). It provides primitives for explicit abo...

Every peer-to-peer system is based on some overlay network connecting its peers. Many of the overlay network concepts proposed in the scientific community are based on the concept of virtual space. These designs are usually highly scalable, but they do not guarantee robustness against adversarial attacks, especially when considering open peer-to-peer systems. In these systems, determined advers...

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In this chapter, we demonstrate through simple queueing models some of the methods that have been developed for the diffusion approximation. Specifically, we first show how the sandwich method is used to establish the diffusion approximation for a multi-server queue, and next show how the uniform attraction and the state-space collapse method is used to establish the diffusion approximation for...

This paper considers a 3nite capacity fork–join queueing model for open assembly systems with arrival and departure synchronizations and presents an approach for enumerating the state space and obtaining the steady state probabilities of the same for such a model under exponential assumptions. Several performance measures like the throughput of the system, fraction of arrivals that actually ent...

Graph has great expressive power to describe the complex relationships among data objects, and there are large graph datasets available. In this paper, we focus ourselves on processing a primitive graph query. We call it reachability query. The reachability query, denoted A D, is to find all elements of a type D that are reachable from some elements in another type A. The problem is challenging...

The index selection problem (ISP) concerns the selection of an appropriate indexes set to minimize the total cost for a given workload under storage constraint. Since the ISP has been proven to be an NP-hard problem, most studies focus on heuristic algorithms to obtain approximate solutions. The problem becomes more difficult for indexes defined on multiple tables such as bitmap join indexes, s...