William C. Cheng

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Hot spots are a major obstacle to achieving scalability in the Internet. At the application layer, hot spots are usually caused by either (a) high demand for some data or (b) high demand for a certain service. This high demand for data or services, is typically the result of a <i>real-life event</i> involving availability of new data or approaching(More)
Many tools and techniques exist for the modeling and analysis of computer and communication systems. These tools are often complex and tailored to a narrow range of problems. The system analysis task often requires coordinated use of multiple tools and techniques which is not supported by currently available systems. The Tangram project goal is to develop(More)
Total Recall is a system that records an individual perspective of the world using personal sensors such as a microphone in a pair of glasses or a camera in a necklace. There are many applications of Total Recall -- patients accurately recording what they've recently eaten, students replaying any part of a class, and so on--that can significantly improve(More)
In a recent paper, we introduced a framework termed Bistro to facilitate the building of scalable widearea upload applications. An example of an important upload application is the submission of personal and business income tax forms over the Internet. Our intent for deploying the Bistro platform is not to rely on adding resources (such as hosts) to the(More)
The primary caregivers (mean age = 63 yr.) of 28 terminally ill veterans (mean age = 67 yr.) who were living at home were surveyed for their concrete and psychosocial needs. The caregivers also completed the Beck Depression Inventory, the Life Satisfaction Index, the Provision of Social Relations scale, and the Burden Inventory. The rank order of concrete(More)
Product-form queuing network models have been widely used to model systems with shared resources such as computer systems (both centralized and distributed), communication networks, and flexible manufacturing systems. Closed multichain product-form networks are inherently more difficult to analyze than open networks, due to the effect of normalization.(More)
Government at all levels is a major collector and provider of data.Our project focuses on the collection of data over wide-area networks (WANs) and addresses the scalability issues that arise in the context of Internet-based massive data collection applications. Furthermore, security, due to the need for privacy and integrity of the data, is a central issue(More)