Browsing by Author "Perera, H. N"

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Structural characteristics of complex supply chain networks
(IEEE, 2017-05-29) Perera, S; Perera, H. N; Kasthurirathna, D
There is a scarcity of analyses of topological properties of real world supply chain networks (SCNs), mainly due to lack of data. Most theoretical research has used the popular Barabasi-Albert (BA) growth model, in which new nodes (firms) entering the network attach preferentially to the existing nodes with more links (contractual relationships), to generate network topologies supposedly representative of real world SCNs. This paper looks at real world SCN topologies using data presented in Willems (2008) and establishes a general set of topological characteristics for the manufacturing sector. Based on observations from twenty six SCNs, it is found that, although manufacturing SCNs exhibit power law node degree distributions, they tend to be hub and spoke like, with hubs that are significantly larger than those predicted by the BA model. Also, the SCNs indicated the presence of closely knit, vertically integrated communities of firms, while highly connected firms were found to avoid connecting with each other. Since the above structural properties are not features of the networks generated by the BA model, it is concluded that a new mechanism is required to model the growth of SCNs.
Embargo
Value chain approach for modelling resilience of tiered supply chain networks
(IEEE, 2017-05-29) Perera, S; Perera, H. N; Kasthurirathna, D
Recent advances in network theory has encouraged the supply chain researchers to investigate the resilience of various supply chain network (SCN) topologies. In a typical SCN model, nodes and links represent the firms and their exchange relationships, respectively. A key requirement in such SCN models is accounting for node and link level heterogeneity, which can be used to more realistically represent the intricacies of real world SCNs. However, this requirement remains largely unaddressed in the contemporary literature. Accordingly, this work attempts to customize the standard network theoretic growth models and resilience metrics, to more closely represent the real world SCN characteristics. In particular, the model proposed in this paper accounts for: (1) the evolution of SCNs through fitness based attachment, (2) the tiered nature observed in real world SCNs, (3) the value added process, from upstream to the downstream of a typical supply chain, which captures heterogeneity of nodes at each tier, (4) the heterogeneity in link weights, and (5) the partial functionality, instead of complete omission, of nodes when simulating failures. The simulation results presented indicate that the proposed model, which closely represents the specific heterogeneous features between the individual network constituents, can be effectively utilized to gain valuable insights on resilience characteristics of real world SCNs.