Browsing by Author "Cheng, Chiaying"

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Bridge and brick network motifs
(2006)
Cheng, Chiaying
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Huang, Chungyuan
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Sun, Chuentsal
;
Hsieh, Jilung
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資訊工程學系
Researchers are increasingly acknowledging the important role of complex networks in numerous scientific contexts. In this paper we define two kinds of motifs-bridge and brick-for exploring and predicting network behaviors and functions and for identifying differences among network structures. Based on an analysis of these motifs in genetic, social, ecological, and engineering networks, we found significant differences in motif functionality and topology. After initially observing similarities between social networks and their genetic, ecological, and engineering counterparts, we eventually noted greater amounts of brick motif in social networks and greater amounts of bridge motif in the other three types. Our conclusion is that bridge and brick motif content analyses can assist researchers in understanding the small-world and clustering properties of network structures and in investigating network functions and behaviors.
Resources, Costs and Epidemic Thresholds in Scale-Free Social Networks
(2008)
Huang, Chungyuan
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Sun, Chuentsai
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Cheng, Chiaying
;
Tsai, Yushiuan
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資訊工程學系
Whether or not a critical threshold exists when epidemic diseases are spread in complex networks is a problem attracting attention from researchers in several disciplines. In 2001, Pastor-Satorras and Vespignani used a computational simulations approach to show that epidemic diseases which spread through scale-free social networks do not have positive critical thresholds. In other words, even if a disease has almost no chance of being transmitted from one person to another, it can still spread throughout a scale-free network. However, they ignored two key factors that have a large impact on epidemic dynamics: economic resource limitations and transmission costs. Every infection event entails tangible or intangible costs in terms of time, energy, or money to the carrier, recipient, or both. Here we apply an agent-based modeling and network-oriented computer simulation approach to analyze the influences of resource limitations and transmission costs on epidemic dynamics and critical thresholds in scale-free networks. Our results indicate that when those resources and costs are taken into consideration, the epidemic dynamics of scale-free networks are very similar to those of homogeneous networks, including the presence of significant critical thresholds. It is hoped that our data Will help epidemiologists, public health professionals, and computer scientists working with core questions of epidemic diseases, estimates of epidemic dynamics and spreading, and effective public health policies and immunization strategies.