Physical Sciences and Mathematics | Open Access Articles

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 7, April 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Go to article

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 6, March 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Go to article

Multicast Algorithms For Mobile Satellite Communication Networks, Ryan W. Thomas

Theses and Dissertations

With the rise of mobile computing and an increasing need for ubiquitous high speed data connections, Internet-in-the-sky solutions are becoming increasingly viable. To reduce the network overhead of one-to-many transmissions, the multicast protocol has been devised. The implementation of multicast in these Low Earth Orbit (LEO) constellations is a critical component to achieving an omnipresent network environment. This research examines the system performance associated with two terrestrial-based multicast mobility solutions, Distance Vector Multicast Routing Protocol (DVMRP) with mobile IP and On Demand Multicast Routing Protocol (ODMRP). These protocols are implemented and simulated in a six plane, 66 satellite LEO constellation. …

Go to article

Moving Towards Massively Scalable Video-Based Sensor Networks, Wu-Chi Feng, Jonathan Walpole, Calton Pu, Wu-Chang Feng

Computer Science Faculty Publications and Presentations

Networking and computing technologies are becoming advanced enough to enable a wealth of diverse applications that will drastically change our everyday lives. Some past examples of these developments include the World Wide Web and wireless data networking infrastructures. As is quite obvious, the World Wide Web has enabled a fundamental change in the way many people deal with day-to-day tasks. Through the web, one can now make on-line reservations for travel, pay bills through on-line banking services, and view personalized on-line newscasts. More recently, developments in wireless technologies have enabled anywhere, anytime access to information over wireless medium. As wireless …

Go to article

Infosphere Project: An Overview, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

We describe the Infosphere project, which is building the systems software support for information-driven applications such as digital libraries and electronic commerce. The main technical contribution is the Infopipe abstraction to support information flow with quality of service. Using building blocks such as program specialization, software feedback, domain-specific languages, and personalized information filtering, the Infopipe software generates code and manage resources to provide the specified quality of service with support for composition and restructuring.

Go to article

Modeling The Transient Rate Behavior Of Bandwidth Sharing As A Hybrid Control System, Kang Li, Molly H. Shor, Jonathan Walpole, Calton Pu

Computer Science Faculty Publications and Presentations

This paper uses hybrid control to model a problem of computer network systems, the dynamic behavior of bandwidth sharing among competing TCP traffic. It has been well known in the computer network community that well-behaved (TCP-friendly) congestion control mechanisms are crucial to the robustness of the Internet. Congestion control determines the transmission rate for each flow. Right now, most TCP-friendly research focuses only on the average throughput behavior without considering how the data is sent out in the short-term (e.g. bursty or smooth). However, recent experimental results show that short-term rate adjustments can change the bandwidth sharing result. Therefore, it …

Go to article

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 5, February 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Go to article

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 4, January 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Go to article

Fuzzycast: Media Broadcasting For Multiple Asynchronous Receivers, Marcel Waldvogel, Wei Deng, Ramaprabhu Janakiraman

All Computer Science and Engineering Research

When using an on-demand media streaming system on top of a network with Multicast support, it is sometimes more efficient to use broadcast to distribute popular content. There has been a lot of research in broadcasting on-demand content to multiple, asynchronous receivers. In this paper, we propose a family of novel, practical techniques for broadcasting on-demand media, which achieve lowest known server/network bandwidth usage and I/O efficient client buffer management, while retaining the simplicity of a frame-based single channel scheme.

Go to article

Local Search And Encoding Schemes For Soft Constraint Minimization Problems, Michael P. Moran, Weixiong Zhang

All Computer Science and Engineering Research

Soft constraint minimization problems (SCMPs) contain hard constraints that cannot be violated and soft constraints that may be violated but carry penalties if not satisfied. In this paper, we first extend local search, WalkSAT in particular, to SCMPs and study the existing SAT encoding schemes for SCMPs. We propose a general encoding method called k-encoding. We then investigate the effects of local search neiborhood structures introduced by encoding schemes and analyze the anytime performance of extended WalkSAT using different encoding methods. Our experimental results on various graph coloring problems show that a direct extension of WalkSAT is most effective, and …

Go to article

Formal Specification And Design Of Mobile Systems, Gruia-Catalin Roman, Christine Julien, Qingfeng Huang

All Computer Science and Engineering Research

Termination detection, a classical problem in distributed computing, is revisited in the new setting provided by the emerging mobile computing technology. A simple solution tailored for use in ad hoc networks is employed as a vehicle for demonstrating the applicability of formal requirements and design strategies to the new field of mobile computing. The approach is based on well understood techniquest in specification refinement, but the methodology is tailored to mobile applications and helps designers address novel concerns such as the mobility of hosts, transient interactions, and specific coordination constructs. The proof logic and programming notation of Mobile UNITY provide …

Go to article

Obiwan - An Internet Protocol Router In Reconfigurable Hardware, Florian Braun, Marcel Waldvogel, John Lockwood

All Computer Science and Engineering Research

The ongoing exponential increase of line speed in the Internet and combined with the uncountable requests for increased functionality of network devices presents a major challenge. These demands call for the use of reprogrammable hardware to provide the required flexible high-speed functionaltiy. The Field Programmable Port Extender (FPX) provides such an environment for development of networking components in reprogrammable hardware. We present the high-speed IP routing components in reprogrammable hardware. We present the high-speed IP routing module "OBIWAN" (Optimal Binary search IP lookup for Wide Area Networks) built on top of an IP processing framework.

Go to article

Phase Transitions And Backbones Of Constraint Minimization Problems, Weixiong Zhang

All Computer Science and Engineering Research

Many real-world problems involve constraints that cannot be all satisfied. The goal toward an overconstrained problem is to find solutions minimizing the total number of constraints violated. We call such a problem constraint minimization problem (CMP). We study the behavior of the phase transitions and backbones of CMP. We first investigate the relationship between the phase transitions of Boolean satisfiability, or precisely 3-SAT (a well-studied NP-complete decision problem), and the phase transitions of MAX 3-SAT (an NP-hard optimization problem). To bridge the gap between the easy-hard-easy phase transitions of 3-SAT, in which solutions of bounded quality, e.g., solutions with at …

Go to article

Synthesizable Design Of A Multi-Module Memory Controller, Sarang Dharmapurikar, John W. Lockwood

All Computer Science and Engineering Research

Random Access Memory (RAM) is a common resources needed by networking hardware modules. Synchronous Dynamic RAM (SDRAM) provides a cost effective solution for such data storage. As the packet processing speeds in the hardware increase memory throughput can be a bottleneck to achieve overall high performance. Typically there are multiple hardware modules which perform different operations on the packet payload and hence all try to access the common packet buffer simultaneously. This gives rise to a need for a memory controller which arbitrates between the memory requests made by different modules and maximizes the memory throughput. This paper discusses the …

Go to article

Embedding Images In Non-Flat Spaces, Robert Pless

All Computer Science and Engineering Research

Multi-dimensional scaling is an analysis tool which transforms pairwise distances between points to an embedding of points in space which are consistent with those distances. Two recent techniques in statistical patter recognition, locally linear embedding (LLE) and Isomap, give a mechanism for finding the structure underlying point sets for which comparisons or distances are only meaningful between nearby points. We give a direct method to extend the embedding algorithm to new topologies, finding the optimal embedding of points whose geodesic distance on a surface mathes the given pairwise distance measurements. Surfaces considered include spheres, cylinders, tori, and their higher dimensional …

Go to article

Indra: A Distributed Approach To Network Intrusion Detection And Prevention, Qi Zhang, Ramaprabhu Janakiraman

All Computer Science and Engineering Research

While advances in computer and communications technology have made the network ubiquitous, they ahve also rendered networked systems vulnerable to malicious attacks orchestrated from a distance. These attacks, usually called cracker attacks or intrusions, start with crackers infiltrating a network through a vulnerable host and then going on to launch further attacks. Crackers depend on increasingly sophisticated techniques like using distributed attack sources. On the other hand, software that guards against them remains rooted in traditional centralized techniques, presenting an easily-targetable single point of failure. Scalable, distributed network intrusion prevention software is sorely needed. We propose Indra - a distributed …

Go to article

The Smart Port Card: An Embedded Unix Processor Architecture For Network Management And Active Networking, John D. Dehart, William D. Richard, Edward W. Spitznagel, David E. Taylor

All Computer Science and Engineering Research

This paper describes the architecture of the Smart Port Card (SPC) designed for use with the Washington University Gigabit Switch. The SPC uses an embedded Intel Pentium processor running open-source NetBSD to support network management and active networking applications. The SPC physically connects between a switch port and a normal link adapter, allowing cell streams to be processed as they enter or leave the switch. In addition to the hardware architecture, this paper describes current and future applications for the SPC.

Go to article

The Fpx Kcpsm Module: An Embedded, Reconfigurable Active Processing Module For The Field Programmable Port Extender (Fpx), Henry Fu, John W. Lockwood

All Computer Science and Engineering Research

While hardware plugins are well suited for processing data with high throughput, software plugins are well suited for implementing complex control functions. A plugin module has been implemented for the FPX that executes software on an embedded soft-core processor. By including this module in an FPX design, it is possible to implement active networking functions on the FPX using both hardware and software. The KCPSM, an 8-bit microcontroller developed by Xilinx Corp., has been embedded into an FPX module. The module includes circuits to be reprogrammed over the network and to execute new programs between the processing of data packerts. …

Go to article

Scalable Ip Lookup For Programmable Routers, David E. Taylor, John W. Lockwood, Todd Sproull, David B. Parlour

All Computer Science and Engineering Research

Continuing growth in optical link speeds places increasing demands on the performance of Internet routers, while deployment of embedded and distributed network services imposes new demands for flexibility and programmability. IP adress lookup has become a significant performance bottleneck for the highest performance routers. New commercial products utilize dedicated Content Addressable Memory (CAM) devides to achieve high lookup speeds. This paper describes an efficient, scalable lookup engine design, able to achieve high-performance with the use of a small portion of a reconfigurable logic device and a commodity Random Access Memory (RAM) device. Based on Eatherton's Tree Bitmap algorithm [1] the …

Go to article

Efficient Queue Management For Tcp Flows, Anshul Kantawala, Jonathan Turner

All Computer Science and Engineering Research

Packets in the Internet can experience large queueing delays during busy periods. Backbone routers are generally engineered to have large buffers, in which packets may wait as long as half a second (assuming FIFO service, longer otherwise). During congestion periods, these bufferfs may stay close to full, subjecting packets to long delays, even when the intrinsic latency of the path is relatively small. This paper studies the performance improvements that can be obtained by using more sophisticated packet schedulers, than are typical of Internet routers. The results show that the large buffers found in WAN routers ocntribute only marginally to …

Go to article

Dres: Internet Resource Management Using Deferred Reservations, Samphel Norden

All Computer Science and Engineering Research

In this proposal, we consider the problem of resource reservation for Integrated Services (IntServ) and Differentiated Services (DiffServ) networks. Current approaches for resource reservation in INtegrated Service Networks adopt an all-or-nothing approach, where partially acquired resources must be released if resources are not available at all routers on the chosen path. Furthermore, under high load, end-systems must retry requests repeatedly leading to inefficient allocation and increased traffic. We propose a new approach called Deferred REServation (DERS) that substantially improves performance (reduces the overall cell rejection probability and increases link utilization) over the all-or-nothing reservation approach. Call admissibility is increased by …

Go to article

Fast Incremental Crc Updates For Ip Over Atm Networks, Florian Braun, Marcel Waldvogel

All Computer Science and Engineering Research

In response to the increasing network speeds, many operations in IP routers and similar devices are being made more efficient. With the advances in other areas of packet processing, the verification and regeneration of cyclic redundancy check (CRC) codes of the data link layer is likely to become a bottleneck in the near future. In this paper, we present a mechanism to defer CRC verification without compromising reliability. This opens the possibility of incremental updates of the CRC. We introduce a new high-speed technique and present efficient implementation, speeding up CRC processing by a factor of 15. Although the paper …

Go to article

A Distributed Annotation System, Robin Dowell

All Computer Science and Engineering Research

One goal of any genome project is the elucidation of hte primary sequence of DNA contained within a given species. While the availability ot the primary sequence itself is valuable, it does not reach its full potential until i has been annotated. Generally defined, annotation is descriptive information or commentary added to text, in this case genomic sequence. Without a mechanism for collecting, recording, and disseminating community-based annotation, a valuable source of information is severely diminshed. In this report I outline the design and implementation of a Distributed Annotation System (DAS). DAS allowes sequence annotations to be decentralized among multiple …

Go to article

Layered Protocol Wrappers For Internet Packet Processing In Reconfigurable Hardware, Florian Braun, John Lockwood, Marcel Waldvogel

All Computer Science and Engineering Research

The ongoing increases of line speed in the Internet backbone combined with the need for increased functionality of network devices presents a major challenge. These demands call for the use of reprogrammable hardware to provide the required flexible, high-speed functionality, at all network layers. The Field Programmable Port Extender (FPX) provides such an environment for development of networking components in reprogrammable hardware. We present a framework to streamline and simplify networking applications that process ATM cells, AAL5 frames, Internet Protocol (IP) packets and UDP datagrams directly in hardware.

Go to article

Implementation Of An Open Multi-Service Router, Fred Kuhns, John Dehart, Ralph Keller, John Lockwood, Prashanth Papu, Jyoti Parwatikar, Ed Spitznagel, David Richard, David Taylor, Jon Turner, Ken Wong

All Computer Science and Engineering Research

This paper describes the design, implementation, and performance of an open, high-performance, dynamically reconfigurable Multi-Service Router (MSR) being developed at Washington University in St. Louis. This router provides an experimentation platform for research on protocols, router software, and hardware design, network management, quality of service and advanced applications. The MSR has been designed to be flexible, without sacrificing performance. It support gigabit links and uses a scalable architecture suitable for supporting hundreds or even thousands of links. The MSR's flexibility makes it an ideal platform for experimental research on dynamically extensible networks that implement higher level functions in direct support …

Go to article

Routing In Overlay Multicast Networks, Sherlia Y. Shi, Jonathan S. Turner

All Computer Science and Engineering Research

Multicast servises can be provided either as a basic network service or as an application-layer service. Higher level multicast implementations often provide more sophisticated features, and since they don't require network supoprt for multicast, they can provide multicast services, where no network layer support is available. Overlay multicast networks offer an intermediate option, potentially combining the flexibility and advanced features of application layer multicast with the greater efficiency of network layer multicast. Overlay multicast networks play an important role in the Internet. Indeed, since Internet Service Providers have been slow to enable IP multicast in their networks, Internet multicast is …

Go to article

A Termination Detection Protocol For Use In Mobile Ad Hoc Networks, Gruia-Catalin Roman, Jamie Payton

All Computer Science and Engineering Research

As computing devices become smaller and wireless networking technologies improve, the popularity of mobile computing continues to rise. In today's business world, many consider devices such as cell phones, PDAs, and laptops as essential tools. As these and other devices become increasingly independent of the wired infrastructure, new kinds of applications that assume an ad hoc network infrastructure will need to be deployed. Such a setting poses new challenges for the software developer, e.g., the lack of an established network topology, bandwidth limitations, and frequent disconnections. In this paper, we begin to explore design strategies for developing applications over ad …

Go to article

Relying On Safe Distance To Ensure Consistent Group Membership In Ad Hoc Networks, Qingfeng Huang, Christine Julien, Gruia-Catalin Roman, Ali Hazemi

All Computer Science and Engineering Research

The design of ad hoc mobile applications often requires the availability of a consistent view of the application state among the participating hosts. Such views are important because they simplify both the programming and verification tasks. Essential to constructing a consitent view is the ability to know what hosts are within proximity of each other, i.e., form a group in support of the particular application. In this paper we propose a protocol that allows hosts within communication range to maintain a consistent view of the group membership despite movement and frequent disconnections. The novel features of this protocol are its …

Go to article

Scheduling Processing Resources In Programmable Routers, Prashanth Pappu, Tilman Wolf

All Computer Science and Engineering Research

To provide flexibility in deploying new protocols and services, general-purpose processing engines are being placed in the datapath of routers. Such network processors are typically simple RISC multiprocessors that perform forwarding and custom application processing of packets. The inherent unpredictability of execution time of arbitrary instruction code poses a significant challenge in providing QoS guarantees for data flows that compete for such processing resources in the network. However, we show that network processing workloads are highly regular and predictable. Using estimates of execution times of various applications on packets of given lengths, we provide a method for admission control and …

Go to article

Design Of Wavelength Converting Switches For Optical Burst Switching, Jeyashankher Ramamirtham, Jonathan Turner

All Computer Science and Engineering Research

Optical Burst Switching (OBS) is an experimental network technology that enables the construction of very high capacity routers, using optical data paths and electronic control. In this paper, we study two designs for wavelength converting switches that are suitable for use in optical burst switching systems and evaluate their performance. Both designs use tunable lasers to implement wavelength conversion. One is strictly nonblocking design, that also requires optical crossbars. The second substitutes Wavelength Grating Routers (WGR) for the optical crossbars, reducing cost, but introducing some potential for blocking. We show how the routing problem for the WGR-based switches can be …

Go to article

Full-Text Articles in Physical Sciences and Mathematics

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 7, April 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 6, March 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

Multicast Algorithms For Mobile Satellite Communication Networks, Ryan W. Thomas

Theses and Dissertations

Moving Towards Massively Scalable Video-Based Sensor Networks, Wu-Chi Feng, Jonathan Walpole, Calton Pu, Wu-Chang Feng

Computer Science Faculty Publications and Presentations

Infosphere Project: An Overview, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Modeling The Transient Rate Behavior Of Bandwidth Sharing As A Hybrid Control System, Kang Li, Molly H. Shor, Jonathan Walpole, Calton Pu

Computer Science Faculty Publications and Presentations

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 5, February 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 4, January 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

Fuzzycast: Media Broadcasting For Multiple Asynchronous Receivers, Marcel Waldvogel, Wei Deng, Ramaprabhu Janakiraman

All Computer Science and Engineering Research

Local Search And Encoding Schemes For Soft Constraint Minimization Problems, Michael P. Moran, Weixiong Zhang

All Computer Science and Engineering Research

Formal Specification And Design Of Mobile Systems, Gruia-Catalin Roman, Christine Julien, Qingfeng Huang

All Computer Science and Engineering Research

Obiwan - An Internet Protocol Router In Reconfigurable Hardware, Florian Braun, Marcel Waldvogel, John Lockwood

All Computer Science and Engineering Research

Phase Transitions And Backbones Of Constraint Minimization Problems, Weixiong Zhang

All Computer Science and Engineering Research

Synthesizable Design Of A Multi-Module Memory Controller, Sarang Dharmapurikar, John W. Lockwood

All Computer Science and Engineering Research

Embedding Images In Non-Flat Spaces, Robert Pless

All Computer Science and Engineering Research

Indra: A Distributed Approach To Network Intrusion Detection And Prevention, Qi Zhang, Ramaprabhu Janakiraman

All Computer Science and Engineering Research

The Smart Port Card: An Embedded Unix Processor Architecture For Network Management And Active Networking, John D. Dehart, William D. Richard, Edward W. Spitznagel, David E. Taylor

All Computer Science and Engineering Research

The Fpx Kcpsm Module: An Embedded, Reconfigurable Active Processing Module For The Field Programmable Port Extender (Fpx), Henry Fu, John W. Lockwood

All Computer Science and Engineering Research

Scalable Ip Lookup For Programmable Routers, David E. Taylor, John W. Lockwood, Todd Sproull, David B. Parlour

All Computer Science and Engineering Research

Efficient Queue Management For Tcp Flows, Anshul Kantawala, Jonathan Turner

All Computer Science and Engineering Research

Dres: Internet Resource Management Using Deferred Reservations, Samphel Norden

All Computer Science and Engineering Research

Fast Incremental Crc Updates For Ip Over Atm Networks, Florian Braun, Marcel Waldvogel

All Computer Science and Engineering Research

A Distributed Annotation System, Robin Dowell

All Computer Science and Engineering Research

Layered Protocol Wrappers For Internet Packet Processing In Reconfigurable Hardware, Florian Braun, John Lockwood, Marcel Waldvogel

All Computer Science and Engineering Research

Implementation Of An Open Multi-Service Router, Fred Kuhns, John Dehart, Ralph Keller, John Lockwood, Prashanth Papu, Jyoti Parwatikar, Ed Spitznagel, David Richard, David Taylor, Jon Turner, Ken Wong

All Computer Science and Engineering Research

Routing In Overlay Multicast Networks, Sherlia Y. Shi, Jonathan S. Turner

All Computer Science and Engineering Research

A Termination Detection Protocol For Use In Mobile Ad Hoc Networks, Gruia-Catalin Roman, Jamie Payton

All Computer Science and Engineering Research

Relying On Safe Distance To Ensure Consistent Group Membership In Ad Hoc Networks, Qingfeng Huang, Christine Julien, Gruia-Catalin Roman, Ali Hazemi

All Computer Science and Engineering Research

Scheduling Processing Resources In Programmable Routers, Prashanth Pappu, Tilman Wolf

All Computer Science and Engineering Research

Design Of Wavelength Converting Switches For Optical Burst Switching, Jeyashankher Ramamirtham, Jonathan Turner

All Computer Science and Engineering Research