Buffer overflow is a serious problem when the software is run as a server on the internet. Especially when the return addresses are overwritten intentionally, the control flow may be changed as the attacker intends. Although there have been proposed several ways to protect attacks that utilize the buffer overflow, the number of the errors owing to the buffer overflow have been increasing gradua...

This paper introduces and analyzes the notion of throughput suboptimality for many-server queueing systems in heavy traffic. The queueing model under consideration has multiple customer classes, indexed by a finite set I, and heterogenous, exponential servers. Servers are dynamically chosen to serve customers, and buffers are available for customers waiting to be served. The arrival rates and t...

One of the main challenges in video transmission is understanding and adapting to the varying network bandwidth. The traditional approach of bandwidth estimation is not accurate as there are many factors like congestion that can delay the arrival rate of the ping packet which may lead to a misconception that the bandwidth was low. Thus, the better approach to this problem will be to estimate th...

We report on an observational study of user response following the OpenSSL remote buffer overflows of July 2002 and the worm that exploited it in September 2002. Immediately after the publication of the bug and its subsequent fix we identified a set of vulnerable servers. In the weeks that followed we regularly probed each server to determine whether its administrator had applied one of the rel...

A great deal of research has been devoted to solving the problem of network congestion posed against the context of increasing Internet traffic. However, there has been little concern regarding improvements of the performance of Internet servers such as Web/Web proxy servers in spite of the projections that the performance bottleneck will shift from networks to endhosts. For example, Web server...

Most existing commercial video servers are designed for a single server. Consequently, the capacity of the system in terms of maximum sustainable concurrent sessions is limited by the performance of the video server hardware. This paper proposes and analyzes the performance of a novel parallel video server architecture where video data are striped across an array of autonomous servers. The arch...

Many embedded devices used to control critical infrastructure assets are based on the Harvard architecture. This architecture separates data and program memory into independent address spaces, unlike the von Neumann architecture, which uses a single address space for data and program code. Buffer overflow attacks in desktop and server platforms based on the von Neumann model have been studied e...

Supervisory control for deadlock-free resource allocation has been an active area of manufacturing systems research. Most work, however, assumes that allocated resources do not fail. Little research has addressed allocating resources that may fail. Automated manufacturing systems have many types of components that may fail unexpectedly. We develop robust controllers for single unit resource all...

We define a class of rate-based service disciplines called Lower-Bounded Rate (LBR) that provides upper bounds on end-to-end delay, end-to-end delay probability distribution, per-server buffer space requirements, and the probability distribution of per-server buffer space. This class includes VirtualClock, PGPS, and Leave-in-Time. We prove these upper bounds, and we also prove that for an impor...

A VOD server handles various types of media such as continuous media (CM) and non-continuous media (NM). Conventional VOD server buffer scheduling algorithms like Round Robin (RR) and Earliest Deadline First (EDF) have tradeoffs between guaranteeing the deadline of CM and getting a fast response time of NM. The former performs well in a NM environment while the latter is suitable for CM. In thi...