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179 results on '"Liu, Wei-Chung"'

13. Development of a strategically driven production facilities management (PFM) framework

Author

Liu, Wei-Chung, Kay, John M., and Groves, Gwyn

Subjects
658, Strategy, Companies, Corporate objectives
Abstract

This thesis presents the results of a programme of research into the development and evaluation of a strategically driven Production Facilities Management (PFM) framework. PFM is the activity of managing production facilities to fully realise the corporate strategic objectives of a manufacturing organisation. Companies with strategies tend to be more successful than companies without them. The concept of manufacturing strategy is an approach to enhance the consistency between the manufacturing function and the direction of the organisation. Consequentially, PFM is the means to ensure these strategic requirements can be fully realised from the facilities management viewpoint. Through the literature review, it was seen that there is a lack of a link between manufacturing strategy and the management of production facilities. From questionnaire surveys and interviews at companies in the manufacturing sector, it was found that the issue of linking facilities management with corporate strategy has been ignored. Therefore, this programme of research not only investigates the context and contents in formulating an appropriate manufacturing strategy in a manufacturing environment but also reviews the most popular methods in relation to maintenance management and performance assessment of the facilities. This programme describes the development of a strategically driven, step-by-step approach that helps a company to capture the strategic requirements of the manufacturing function, measure the performance of existing production facilities and supports the decision-making analysis tasks. The primary contribution of the work presented in this thesis was the development of an implementation framework and an associated implementation workbook which comprise a set of stages and implementation sections that a user can use to carry out the process of capturing the strategic requirements and realise them with support from an appropriate PFM framework and a systematic, step-by-step implementation process.

Published
2000

20. ESM2.docx from A network-based measure of functional diversity in food webs

Author

Lin, Wen-hsien, Lai, Shu-mei, Davis, Andrew J., Liu, Wei-chung, and Jordan, Ferenc

Subjects
respiratory system, human activities
Abstract

Biodiversity is measured from various perspectives. One of them, functional diversity, quantifies the heterogeneity in species traits and roles in an ecosystem. One important aspect of species roles is their interactions with other species, i.e. their network role. We therefore investigate here functional diversity from the network perspective. Species differ in their network positions in a food web, having different interaction patterns. We developed a measure for quantifying the diversity in species interaction patterns in a food web. We examined the relationship between interaction diversity and several global network properties for 92 food webs. Our results showed that high interaction diversity occurs in sparsely connected and less cohesive food webs. High interaction diversity also occurred in food webs with more clusters and high network modularity. We also quantified several conventional functional diversity indices and demonstrate that they show little or no correlation with interaction diversity. Our proposed diversity index therefore provides a measure complementary to current concepts of functional diversity.

Published
2022
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34. A network perspective on the topological importance of enzymes and their phylogenetic conservation

Author

Jordán Ferenc, Davis Andrew J, Lin Wen-hsien, Liu Wei-chung, Yang Hsih-te, and Hwang Ming-jing

Subjects
Computer applications to medicine. Medical informatics, R858-859.7, Biology (General), QH301-705.5
Abstract

Abstract Background A metabolic network is the sum of all chemical transformations or reactions in the cell, with the metabolites being interconnected by enzyme-catalyzed reactions. Many enzymes exist in numerous species while others occur only in a few. We ask if there are relationships between the phylogenetic profile of an enzyme, or the number of different bacterial species that contain it, and its topological importance in the metabolic network. Our null hypothesis is that phylogenetic profile is independent of topological importance. To test our null hypothesis we constructed an enzyme network from the KEGG (Kyoto Encyclopedia of Genes and Genomes) database. We calculated three network indices of topological importance: the degree or the number of connections of a network node; closeness centrality, which measures how close a node is to others; and betweenness centrality measuring how frequently a node appears on all shortest paths between two other nodes. Results Enzyme phylogenetic profile correlates best with betweenness centrality and also quite closely with degree, but poorly with closeness centrality. Both betweenness and closeness centralities are non-local measures of topological importance and it is intriguing that they have contrasting power of predicting phylogenetic profile in bacterial species. We speculate that redundancy in an enzyme network may be reflected by betweenness centrality but not by closeness centrality. We also discuss factors influencing the correlation between phylogenetic profile and topological importance. Conclusion Our analysis falsifies the hypothesis that phylogenetic profile of enzymes is independent of enzyme network importance. Our results show that phylogenetic profile correlates better with degree and betweenness centrality, but less so with closeness centrality. Enzymes that occur in many bacterial species tend to be those that have high network importance. We speculate that this phenomenon originates in mechanisms driving network evolution. Closeness centrality reflects phylogenetic profile poorly. This is because metabolic networks often consist of distinct functional modules and some are not in the centre of the network. Enzymes in these peripheral parts of a network might be important for cell survival and should therefore occur in many bacterial species. They are, however, distant from other enzymes in the same network.

Published
2007
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46. Howcare

Author

Huang, Liang-Cheng, primary, Liu, Wei-Chung, additional, and Chou, Seng-Cho T., additional

Published
2013
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