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Articles 12181 - 12210 of 12790

Full-Text Articles in Physical Sciences and Mathematics

Programming Active Networks Using Active Pipes, Ralph Keller, Jeyashankher Ramamirtham, Tilman Wolf, Bernhard Plattner Jan 2000

Programming Active Networks Using Active Pipes, Ralph Keller, Jeyashankher Ramamirtham, Tilman Wolf, Bernhard Plattner

All Computer Science and Engineering Research

Active networks allow customized processing of data traffic within the network which can be used by applications to improve the quality of their sessions. To simplify development of active applications in a heterogeneous environment, we propose active network pipes as a programming abstraction to specify transmission and processing requirements. We describe a routing algorithm that maps application session requirements onto network resources and determines an optimal route through the network transiting all required processing sites. Additionally, we propose a network software architecture to implement the functionality required to support active pipes.


Hello, World: A Simple Application For The Field Programmable Port Extender (Fpx), John Lockwood, David Lim Jan 2000

Hello, World: A Simple Application For The Field Programmable Port Extender (Fpx), John Lockwood, David Lim

All Computer Science and Engineering Research

The FPX provides simple and fast mechanisms to process cells or packets. By performing all computations in FPGA hardware, cells and packets can be processing at the full line speed of the card [currently 2.4 Gbits/sec]. A sample application, called 'Hello World' has been developed that illustrates how easily an application can be implemented on the FPX. This application uses the FPGA hardware to search for a string on a particular flow and selectively replace contents of the payload. The resulting circuit operates at 119 MHz on a Xilinx XCV 1000E-FG680-7, and occupies less than 1% of the available gates …


Network Security Versus Network Connectivity: A Framework For Addressing The Issues Facing The Air Force Medical Community, Franklin E. Cunningham Jr. Dec 1999

Network Security Versus Network Connectivity: A Framework For Addressing The Issues Facing The Air Force Medical Community, Franklin E. Cunningham Jr.

Theses and Dissertations

The Air Force has instituted Barrier Reef to protect its networks. The Air Force medical community operates network connections that are incompatible with Barrier Reef. To overcome this problem, OASD(HA) directed the Tri-Service Management Program Office (TIMPO) to develop an architecture that protects all military health systems and allows them to link with all three services and outside partners. This research studied the underlying networking issues and formed a framework based on data from network experts from the Air Force's medical centers and their base network organizations. The findings were compared TIMPO and a composite framework was developed that more …


Work In Progress: Automating Proportion/Period Scheduling, David Steere, Jonathan Walpole, Calton Pu Dec 1999

Work In Progress: Automating Proportion/Period Scheduling, David Steere, Jonathan Walpole, Calton Pu

Computer Science Faculty Publications and Presentations

The recent effort to define middleware capable of supporting real-time applications creates the opportunity to raise the level of abstraction presented to the programmer. We propose that proportion/period is a better abstraction for specifying resource needs and allocation than priorities. We are currently investigating techniques to address some issues that are restricting use of proportion/period scheduling to research real-time prototypes. In particular, we are investigating techniques to automate the task of selecting proportion and period, and that allow proportion/period to incorporate job importance under overload conditions.


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 9, November 1999, College Of Engineering And Computer Science, Wright State University Nov 1999

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 9, November 1999, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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


Investigation Of Image Feature Extraction By A Genetic Algorithm, Steven P. Brumby, James P. Theiler, Simon J. Perkins, Neal R. Harvey, John J. Szymanski, Jeffrey J. Bloch, Melanie Mitchell Nov 1999

Investigation Of Image Feature Extraction By A Genetic Algorithm, Steven P. Brumby, James P. Theiler, Simon J. Perkins, Neal R. Harvey, John J. Szymanski, Jeffrey J. Bloch, Melanie Mitchell

Computer Science Faculty Publications and Presentations

We describe the implementation and performance of a genetic algorithm which generates image feature extraction algorithms for remote sensing applications. We describe our basis set of primitive image operators and present our chromosomal representation of a complete algorithm. Our initial application has been geospatial feature extraction using publicly available multi-spectral aerial-photography data sets. We present the preliminary results of our analysis of the efficiency of the classic genetic operations of crossover and mutation for our application, and discuss our choice of evolutionary control parameters. We exhibit some of our evolved algorithms, and discuss possible avenues for future progress.


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 8, October 1999, College Of Engineering And Computer Science, Wright State University Oct 1999

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 8, October 1999, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 7, September 1999, College Of Engineering And Computer Science, Wright State University Sep 1999

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 7, September 1999, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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


Fine-Grain Period Adaptation In Soft Real-Time Environments, David Steere, Joshua Gruenberg, Dylan Mcnamee, Calton Pu, Jonathan Walpole Sep 1999

Fine-Grain Period Adaptation In Soft Real-Time Environments, David Steere, Joshua Gruenberg, Dylan Mcnamee, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Reservation-based scheduling delivers a proportion of the CPU to jobs over a period of time. In this paper we argue that automatically determining and assigning this period is both possible and useful in general purpose soft real-time environments such as personal computers and information appliances. The goal of period adaptation is to select the period over which a job is guaranteed to receive its portion of the CPU dynamically and automatically. The choice of period represents a trade-off between the amount of jitter observed by the job and the overall efficiency of the system. Secondary effects of period include quantization …


Qos Scalability For Streamed Media Delivery, Charles Krasic, Jonathan Walpole Sep 1999

Qos Scalability For Streamed Media Delivery, Charles Krasic, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Applications with real-rate progress requirements, such as mediastreaming systems, are difficult to deploy in shared heterogenous environments such as the Internet. On the Internet, mediastreaming systems must be capable of trading off resource requirements against the quality of the media streams they deliver, in order to match wide-ranging dynamic variations in bandwidth between servers and clients. Since quality requirements tend to be user- and task-specific, mechanisms for capturing quality of service requirements and mapping them to appropriate resource-level adaptation policies are required. In this paper, we describe a general approach for automatically mapping user-level quality of service specifications onto resource …


Guest Editorial: Special Section On Acousto-Optic Devices And Optical Information Processing: Research And Developments, Partha P. Banerjee, Ting-Chung Poon Jul 1999

Guest Editorial: Special Section On Acousto-Optic Devices And Optical Information Processing: Research And Developments, Partha P. Banerjee, Ting-Chung Poon

Electrical and Computer Engineering Faculty Publications

This guest editorial provides an overview of the topical area and an introduction to the articles featured in the special section.


Examination Of Beam Propagation In Misaligned Holographic Gratings And Comparison With The Acousto-Optic Transfer Function Model For Profiled Beams, Monish Ranjan Chatterjee, David D. Reagan Jul 1999

Examination Of Beam Propagation In Misaligned Holographic Gratings And Comparison With The Acousto-Optic Transfer Function Model For Profiled Beams, Monish Ranjan Chatterjee, David D. Reagan

Electrical and Computer Engineering Faculty Publications

A transfer function formalism developed earlier for the propagation of profiled optical beams through acousto-optic Bragg cells is revisited and applied to a thick holographic grating. The results based on the holographic coupled wave model and the acousto-optic multiple scattering model are shown to be compatible, and equivalent parameters such as the Q and grating strength are defined for the two systems. Results for a Gaussian spatial profile are numerically computed and compared. For the holographic grating, a profiled beam may be interpreted as an angular misalignment or Bragg-angle mismatch problem. The case of Bragg-wavelength mismatch is also investigated for …


Laser Beam Profile Deformation Effect During Bragg Acousto-Optic Interaction: A Non-Paraxial Approximation, Ray S. Huang, Chen-Wen Tarn, Partha P. Banerjee, Doungchin Cao Jul 1999

Laser Beam Profile Deformation Effect During Bragg Acousto-Optic Interaction: A Non-Paraxial Approximation, Ray S. Huang, Chen-Wen Tarn, Partha P. Banerjee, Doungchin Cao

Electrical and Computer Engineering Faculty Publications

It is commonly known that the spatial profiles of the diffracted light beams during Bragg acousto-optic interaction are distorted due to the Bragg angle selection mechanism. All the conventional studies on this effect use the paraxial approximation. But this approximation should be amended when the incident angle of the light is large enough that the diffracted light waves do not propagate closely along the optic axis of the acousto-optic diffraction system. By using a spatial Fourier transform approach, we rigorously study the light beam profile deformation effect of the diffracted light during the Bragg acousto-optic interaction beyond the paraxial approximation. …


Dynamic And Interactive 3d Simulation Over The World Wide Web, Rajesh Vennam Jul 1999

Dynamic And Interactive 3d Simulation Over The World Wide Web, Rajesh Vennam

Electrical & Computer Engineering Theses & Dissertations

The thesis presents the development of a new and novel three-dimensional simulation tool over the WWW using Virtual Reality Modeling Language (VRML). VRML is a 3D analog to HTML and serves as a simple, multiplatform language for publishing 3D Web pages. In general, most people use VRML for developing three-dimensional models or worlds that provide little or no interaction for the users. This tool combines interaction and dynamic object creation. A thorough study of VRML is done to explore the features of VRML that could be combined to develop methodologies for creation of dynamic and interactive 3D objects over the …


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 6, June 1999, College Of Engineering And Computer Science, Wright State University Jun 1999

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 6, June 1999, 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.


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 5, May 1999, College Of Engineering And Computer Science, Wright State University May 1999

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 5, May 1999, 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.


Two Approaches To Critical Path Scheduling For A Heterogeneous Environment, Guangxia Liu May 1999

Two Approaches To Critical Path Scheduling For A Heterogeneous Environment, Guangxia Liu

Computer Science Theses & Dissertations

Advances in computing and networking technologies are making large scale distributed heterogeneous computing a reality. Multi-Disciplinary Optimization (MDO) is a class of applications that is being addressed under this paradigm. It consists of multiple heterogeneous modules interacting with each other to solve an overall design problem. An efficient implementation of such an application requires scheduling heterogeneous modules (with different computing and disk 1/0 requirements) on a heterogeneous set of resources (with different CPU, memory, disk IO specifications).

Given a set of tasks and a set of resources, an optimal schedule of the tasks on the resources is very hard to …


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 4, April 1999, College Of Engineering And Computer Science, Wright State University Apr 1999

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 4, April 1999, 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.


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 3, March 1999, College Of Engineering And Computer Science, Wright State University Mar 1999

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 3, March 1999, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 2, February 1999, College Of Engineering And Computer Science, Wright State University Feb 1999

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 2, February 1999, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 1, January 1999, College Of Engineering And Computer Science, Wright State University Jan 1999

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 1, January 1999, 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.


Bargaining With Deadlines, Tuomas Sandholm, Nir Vulkan Jan 1999

Bargaining With Deadlines, Tuomas Sandholm, Nir Vulkan

All Computer Science and Engineering Research

This paper analyzes automated distributive negotiation where agents have firm deadlines that are private information. The agents are allowed to make and accept offers in any order in continuous time. We show that the only sequential equilibrum outcome is the one where the agents wait until the first deadline, at which point that agent concedes everything to the other. This holds for pure and mixed strategies. So, interestingly, rational agents can never agree to a nontrivial split because offers signal enough weakness of bargaining power (early deadline) so that the recipient should never accept. Similarly, the offerer knows that it …


Constructing Speculative Demand Functions In Equilibrium Markets, Tuomas Sandholm, Fredrik Ygge Jan 1999

Constructing Speculative Demand Functions In Equilibrium Markets, Tuomas Sandholm, Fredrik Ygge

All Computer Science and Engineering Research

In computational markets utilizing algorithms that establish a general equilibrium, competitive behavior is usually assumed: each agent makes its demand (supply) decisions so as to maximize its utility (profit) assuming that it has no impact on market prices. However, there is a potential gain from strategic behavior via speculating about others because an agent does affect the market prices, which affect the supply/demand decisions of others, which again affect the market prices that the agent faces. Determining the optimal strategy when the speculator has perfect knowledge about the other agents is a well known problem which has been studied in …


A Rapid Development Of Dependable Applications In Ad Hoc Mobility, Amy L. Murphy Jan 1999

A Rapid Development Of Dependable Applications In Ad Hoc Mobility, Amy L. Murphy

All Computer Science and Engineering Research

Advances in wireless communication and network computing technologies make possible new kinds of applications involving transient interactions among physical components that move across a wide range of spaces, from the confines of a room to the airspace across an ocean, and require no fixed networking infrastructure to communicate with one another. Such components may come together to form ad hoc networks for the purpose of exchanging information or in order to engage in cooperative task-oriented behaviors. Ad hoc networks are assembled, reshaped and taken apart as components move in and out of communication range; all interactions are transient; computations become …


Reliable Communication For Highly Mobile Agents, Amy L. Murphy, Gian Pietro Picco Jan 1999

Reliable Communication For Highly Mobile Agents, Amy L. Murphy, Gian Pietro Picco

All Computer Science and Engineering Research

The provision of a reliable communication infrastructure for mobile agents is still an open research issue. The challenge to reliability we address in this work does not come from the possibility of faults, but rather from the mere presence of mobility, which slightly complicates the problem of ensuring the delivery of information even in a fault-free network. For instance, the asynchronous nature of message passing and agent migration may cause situations where messages forever chase a mobile agent that moves frequently from one host to another. Current solutions rely on conventional technologies that either do not provide a solution for …


An Algorithm For Optimal Winner Determination In Combinatorial Auctions, Tuomas Sandholm Jan 1999

An Algorithm For Optimal Winner Determination In Combinatorial Auctions, Tuomas Sandholm

All Computer Science and Engineering Research

Combinatorial auctions, i.e. auctions where bidders can bid on combinations of items, tend to lead to more efficient allocations than traditional auctions in multi-item auctions where the agents' valuations of the items are not additive. However, determining the winners so as to maximize revenue is NP-complete. First, existing approaches for tackling this problem are reviewed: exhaustive enumeration, dynamic programming, approximation algorithms, and restricting the alloable combinations. Then we present our search algorithm for optimal winner determination. Experiments are shown on several bid distributions. The algorithm allows combinatorial auctions to scale up to significantly larger numbers of items and bids than …


Revenue Equivalence Of Leveled Commitment Contracts, Tuomas Sandholm, Yunhong Zhou Jan 1999

Revenue Equivalence Of Leveled Commitment Contracts, Tuomas Sandholm, Yunhong Zhou

All Computer Science and Engineering Research

In automated negotiation systems consisting of self-interested agents, contracts have traditionally been binding. Leveled commitment contracts - i.e. contracts where each party can decommit by paying a predetermined penalty - were recently shown to improve expected social welfare even if agents decommit insincerely in Nash equilibrium. Such contracts differ based on whether agents have to declare their decommitting decisions sequentially or simultaneously, and whether or not agents have to pay the penalties if both decommit. For a given contract, these protocols lead to different decommitting thresholds and probabilities. However, this paper shows that, surprisingly, each protocol leads to the same …


A Proposal For A High-Performance Active Hardware Architecture, Tilman Wolf Jan 1999

A Proposal For A High-Performance Active Hardware Architecture, Tilman Wolf

All Computer Science and Engineering Research

Current research in Active Networking is focused on developing software architectures and defining funtionality of Execution Environments. While active network systems show superior functionality compared to traditional networks, they only operate at substantially lower link speeds. To increase the acceptance of Active Network in environments where link speeds of several Gb/s are common, we propose a hardware architecture that performs high-speed packet handling while providing the same flexibility as a common software system. The design exploits the independence between data streams for parallel processing. To measure the impact of different design decisions on the performance of the system, we also …


The Design And Performance Of A Pluggable Protocols Framework For Object Request Broker Middleware, Fred Kuhns, Carlos O'Ryan, Douglas C. Schmidt, Jeff Parsons Jan 1999

The Design And Performance Of A Pluggable Protocols Framework For Object Request Broker Middleware, Fred Kuhns, Carlos O'Ryan, Douglas C. Schmidt, Jeff Parsons

All Computer Science and Engineering Research

To be an effective platform for performance-sensitive real-time and embedded applications, off-the-shelf OO middleware like CORBA, DCOM, and Java RMI must preserve communication-layer quality of service (QoS) properties to applications end-to-end. However, conventional OO middleware interoperability protocols, such as CORBA's GIOP/IIOP or DCOM's MS-RPC, are not well suited for applications that cannot tolerate the message footprint size, latency, and jitter associated with general-purpose messaging and transport protocols. It is essential, therefore, to develop standard plugable protocols frameworks that allow custom messaging and transport protocols to be configured flexibly and used transparently by applications. This paper provides three contributions to research …


Anmac: A Novel Architectural Framework For Network Management And Control Using Active Networks, Samphel Norden Jan 1999

Anmac: A Novel Architectural Framework For Network Management And Control Using Active Networks, Samphel Norden

All Computer Science and Engineering Research

In this paper, we propose a new framework called Active Network Management and Control (ANMAC) for the management and control of high speed networks. The software architecture in ANMAC allows routers to execute dynamically loadable kernel plug-in modules which perform diagnostic functions for network management. ANMAC uses mobile probe packets to perform efficient resource reservation (using our novel reservation scheme), facilitate feedback-based congestion control, and to provide "distributed debugging" of complex anomalous network behavior. ANMAC also provides security measures against IP spoofing, and other security attacks. The network manager has the flexibility to install custom scripts in routers for tracking …