A notable requirement of clusters is to maximize its processing performance. Lots of work in this area has been done to optimize the system performance by improving certain metric such as reliability, availability, security and so on. However, most of them assumes that the system is running without interruption and seldom considers the system’s intrinsic characteristics, such as failure rate, r...

In mobile ad hoc peer-to-peer (M-P2P) networks, economic models become a necessity for enticing non-cooperative mobile peers to provide service. M-P2P users may issue queries with varying constraints on query response time, data quality of results and trustworthiness of the data source. Hence, we propose ConQuer, which is an economic incentive model for the efficient processing of constraint qu...

Integrity is usually considered to be at odds with security in multilevel databases. Integrity constraints enforce conditions on relations between data, while security constraints enforce separation between data. If an integrity constraint is defined over data at different security levels, a direct conflict results. However, the solution is not to sacrifice the integrity constraint altogether. ...

Most production scheduling problems, including the standard flexible job-shop scheduling problem (FJSP), assume that machines are continuously available. However, in most realistic situations, machines may become unavailable during certain periods due to preventive maintenance (PM). In this paper, a flexible job-shop scheduling problem with machine availability constraints is considered. Each m...

Laboratory workloads increased substantially between 1966 and 1974, the total number of laboratories was reduced, and productivity improved. The trends are likely to continue, but in the present economic situation the availability of accommodation will be an important constraint in determining the pattern of future development.

Up to now distribution is barely considered during the design phase. This complicates finding a reasonable trade off between ‘availability’ and ‘load balance’ in a distributed component-based system. Therefore, the Distribution Constraint Language ‘DCL’ is introduced in this paper for expressing distribution requirements during design. This visual language facilitates designing, running and mai...

This paper studies the two-machine permutation flowshop scheduling problem with anticipatory setup times and an availability constraint imposed only on the first machine. The objective is to minimize the makespan. Under the assumption that interrupted jobs can resume their operations, we present a polynomial-time approximation scheme (PTAS) for this problem.

In this paper we study the two-machine owshop scheduling problem with an availability constraint on the rst machine. We rst show that the worst-case error bound 2 of the heuristic provided by Lee [4] is tight. We then develop an improved heuristic with a worst-case error bound of 3 . c © 2000 Elsevier Science B.V. All rights reserved.