James W. Roberts

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In this paper we study the statistics of the realized throughput of elastic document transfers, accounting for the way network bandwidth is shared dynamically between the randomly varying number of concurrent flows. We first discuss the way TCP realizes statistical bandwidth sharing, illustrating essential properties by means of packet level simulations.(More)
Recently the Internet has witnessed the emergence of content distribution networks (CDNs). In this paper we study the problem of optimally replicating objects in CDN servers. In our model, each Internet Autonomous System (AS) is a node with nite storage capacity for replicating objects. The optimization problem is to replicate objects so that when clients(More)
It is proposed to apply an integrated admission control scheme to both streaming flows and elastic flows. It is assumed that streaming flow packets are served with priority in network queues so that admission control ensures minimal delay for audio and video applications while preserving the throughput of document transfers. An implicit measurementbased(More)
We derive recurrence relations enabling the direct calculation of the joint distribution of the number of busy channels in a circuit-switched network whose offered traffic streams require a variable number of channels on each link. Approximate congestion probability calculation methods are developed based on the estimation of marginal link occupancy(More)
We present a rate control algorithm adapted to MPEG video coders ensuring that output conforms to the parameters of a leaky-bucket network access controller. The algorithm avoids unpredictable rate variations without the rigidity and systematic coding delay of constant bit-rate (CBR) coders, and makes possible resource provision for guaranteed quality of(More)
This paper investigates consumer switching costs in the context of health insurance markets, where adverse selection is a potential concern. Switching costs contribute to poor choices when the market environment changes and consumers do not adjust appropriately. Though previous work has studied the problems of adverse selection and consumer choice(More)
We study the behavior, strategy, and performance of investors who purchase homes with the intention of quickly re-selling or ”flipping” them for a profit. Using detailed micro-level data on transactions in the Los Angeles metro area from 1988-2008 and a novel research design, we identify the presence of two very distinct types of flippers in the market. The(More)