Washington University in St. Louis

Latest Content From Washington University in St. Louis

Whitepaper: Robust TCP Stream Reassembly in the Presence of Adversaries

by Washington University in St. LouisJan 01, 2008

TCP packet reassembly is a fundamental building block for analyzing network traffic at higher semantic levels. However, engineering packet reassembly hardware becomes highly challenging when it must resist attempts by adversaries to subvert it. This paper presents a hardware based reassembly system designed for both efficiency and robust performance in the face of such attacks.

Whitepaper: Intelligent Packet Discard Policies for Improved TCP Queue Management

by Washington University in St. LouisJan 01, 2008

Studies have shown that suitably-designed packet discard policies can improve the performance of fair queuing mechanisms in internet routers. The Queue State Deficit Round Robin algorithm (QSDRR) preferentially discards from long queues introduces hysteresis into the discard policy to minimize synchronization among TCP flows. QSDRR discards packets that give higher throughput than simpler queuing mechanisms, such as Tail-Drop, RED and Blue. However, because previously been queued, it can significantly increase the memory bandwidth requirements of high performance routers. This paper highlights alternatives to QSDRR that gives comparable performance, while allowing packets to be discarded on arrival, saving memory bandwidth.

Whitepaper: Context-Sensitive Access Control for Open Mobile Agent Systems

by Washington University in St. LouisJan 01, 2008

Ubiquitous computing devices communicate wirelessly, opportunistically forming ad hoc networks not connected to a wired infrastructure. These networks can include a handful of devices or thousands of heterogeneous components, making coordinating and mediating their competing needs a massive task. This research paper focuses on systems that use tuple spaces as a basis for coordination among mobile application agents. The original Linda model provides a centralized tuple space where application agents exchange information using content-based matching of patterns against data.

Whitepaper: Context-Sensitive Data Structures Supporting Software Development in Ad Hoc Mobile Settings

by Washington University in St. LouisJan 01, 2008

Context-aware computing has been advocated as a solution to dealing with the programming complexity associated with such development efforts. Context-awareness refers to the ability of an application to adapt its behavior in response to environmental changes. Typically, in context-aware systems, sensors gather information about the environment, and the collected information is delivered to the application. Context-aware office applications such as Active Badge and PARCTab, as well as tour guide applications such as Cyberguide and GUIDE, for example, rely on events generated by a location sensor to trigger the update of a person’s display to reflect the current physical location.

Whitepaper: Service Oriented Computing Imperatives in Ad Hoc Wireless Settings

by Washington University in St. LouisJan 01, 2008

This research paper discusses about Service Oriented Computing Imperatives in Ad Hoc Wireless Settings. Service oriented computing offers a solution soc imperative in ad hoc wireless settings 2 to this problem. Service oriented computing is designed to facilitate sharing of capabilities while minimizing the amount of functionality a single host needs to possess. Such a design is effective in ad hoc networks where storage space on individual hosts is at a premium, yet a large number of hosts can contribute small code fragments resulting in a rich set of capabilities being available in the network as a whole.

Whitepaper: A Component Deployment Mechanism Supporting Service Oriented Computing in Ad Hoc Networks

by Washington University in St. LouisJan 01, 2008

The continually improving performance of mobile computing devices has stimulated a migration from traditional desktop systems to mobile devices. Reliable deployment of components in such demanding settings requires a different design approach for the mechanisms that perform these functions. This research paper from Washington University in St. Louis proposes a mechanism for component deployment that is adapted for use in ad hoc networks, and, as such, can cope with the effects of disconnection and transient connectivity. It presents the general architecture for the mechanism and follows it with a discussion of a Java-based implementation of the model.

Whitepaper: The Power Of Negative Thinking: Government Regulation And Economic Performance

by Washington University in St. LouisJan 01, 2008

This paper from Washington University in St. Louis describes to sum up the response of the economy to supply-oriented tax policy will be greatly enhanced by reducing the numerous regulatory obstacles to economic activity. Failure to eliminate or at least substantially cut back the regulatory inhibitions to work, invest, and produce will result in disappointing returns from tax policy changes. Government policymakers must come to realize the lack of symmetry in the two different policy mechanisms: tax changes can provide strong incentives to undertake private economic activity, but regulation can provide a simple but effective veto.