Relation algebra operations on formal contexts.

This paper discusses the use of relation algebra operations on formal contexts. These operations are a generalisation of some of the context operations that are described in the standard FCA textbook (Ganter & Wille, 1999). This paper extends previous research in this area with respect to applications and implementations. It also describes a software tool (FcaFlint) which in combination with FcaStone facilitates the application of relation algebra operations to contexts stored in many formats.

Representations and evolutionary operators for the scheduling of pump operations in water distribution networks.

Reducing the energy consumption of water distribution networks has never had more significance. The greatest energy savings can be obtained by carefully scheduling the operations of pumps. Schedules can be defined either implicitly, in terms of other elements of the network such as tank levels, or explicitly by specifying the time during which each pump is on/off. The traditional representation of explicit schedules is a string of binary values with each bit representing pump on/off status during a particular time interval. In this paper, we formally define and analyze two new explicit representations based on time-controlled triggers, where the maximum number of pump switches is established beforehand and the schedule may contain less switches than the maximum. In these representations, a pump schedule is divided into a series of integers with each integer representing the number of hours for which a pump is active/inactive. This reduces the number of potential schedules compared to the binary representation, and allows the algorithm to operate on the feasible region of the search space. We propose evolutionary operators for these two new representations. The new representations and their corresponding operations are compared with the two most-used representations in pump scheduling, namely, binary representation and level-controlled triggers. A detailed statistical analysis of the results indicates which parameters have the greatest effect on the performance of evolutionary algorithms. The empirical results show that an evolutionary algorithm using the proposed representations improves over the results obtained by a recent state-of-the-art Hybrid Genetic Algorithm for pump scheduling using level-controlled triggers.

Enhancing the link between business and operations strategy.

This paper reprots on the use of banchmarking to improve the links between business and operations strategies. The use of benchmarking as a toll to facilitate improvements in these crucial links is examined. The existing literature on process benchmarking is used to from a structured questionnaire to apply to six case studies of major manuifacturing companies. Four of these case studies are presented in this paper to highlight the use of benchmarking in this application. Initial researh results are presented drawing upon the critical success factors indentified both in the literature and on the case results. Recommendations for further work are outlined

Benchmarking the business and operations strategy link.

This paper reports on the use of benchmarking to improve the links between business and operations strategies. The use of benchmarking as a tool to facilitate improvement in these crucial links is examined. The existing literature on process benchmarking is used to form a structured questionnaire to apply to six case studies of major maunfacturing companies. Four of these case studies are presented drawing upon the critical success factors identified both in the literature and on the case results. Recommendations for further work are outlined.