Modeling and Generating TCP Application Workloads INVITED PAPER (2009)
Félix Hernández-campos, Kevin Jeffay, F. Donelson Smith
Abstract — In order to perform valid experiments, traffic generators used in network simulators and testbeds require contemporary models of traffic as it exists on real network links. Ideally one...
Long Le, Jay Aikat, Kevin Jeffay, F. Donelson Smith
Abstract — We present an empirical study of the effects of active queue management (AQM) and explicit congestion notification (ECN) on the distribution of response times experienced by users...
Sync-TCP: Using GPS Synchronized Clocks for Early Congestion Detection in TCP (2008)
Michele Clark Weigle, Kevin Jeffay, F. Donelson Smith
TCP, packet loss is the sole indicator of network congestion. Even so, TCP hosts are not explicitly notified of lost packets, but must rely on timeouts and duplicate acknowledgements (ACKs) to...
Aksj Jay Aikat, Jasleen Kaur, F. Donelson Smith, Ally Sanjeewa Athuraliya, Victor H. Li, ...
Recommendations on queue management and congestion avoidance in the Internet.
Multi-Resolution Anomaly Detection for the Internet (2008)
Lingsong Zhang, Zhengyuan Zhu, Kevin Jeffay
Abstract—In the context of Internet traffic anomaly detection, we will show that some outliers in a time series can be difficult to detect at one scale while they are easy to find at another scale....
Long Le, Jay Aikat, Kevin Jeffay, Don Smith, Long Le, Jay Aikat, ...
An AQM goal was minimizing delays for interactive applications such as web browsing [RFC 2309] – This is achieved by minimizing the average queue size in routers
HTTP SOURCE TRAFFIC MODELING 1 Stochastic Models for Generating Synthetic HTTP Source Traffic (2008)
Jin Cao, William S. Clevel, Yuan Gao, Kevin Jeffay, F. Donelson Smith, Michele Weigle
Abstract — New source-level models for aggregated HTTP traffic and a design for their integration with the TCP transport layer are built and validated using two large-scale collections of TCP/IP...
A Two-Dimensional Audio Scaling Enhancement to an Internet (2008)
Videoconferencing System, Peter Nee, Kevin Jeffay, Michele Clark, Gunner Danneels
ABSTRACT: Without widely deployed mechanisms for resource reservation, adaptive, best-effort techniques are the only methods of congestion control available to interactive, real-time applications....
Mark Parris, Kevin Jeffay, Don Smith
Abstract: In the best-effort Internet, there is a fundamental tension between responsive and unresponsive flows. During periods of congestion, responsive flows reduce the load they generate while...
On the Partitioning of Function in Distributed Synchronous Collaboration Systems (2008)
: A large number of experimental (and a few commercial) distributed synchronous collaboration support systems have been developed to date for the UNIX 1 /X environment. These systems typically fall...
Why Using the Request Abstraction in Proportional Share Allocation Systems is Useful ? (2008)
Ion Stoica, Hui Zhang, Kevin Jeffay
ion in Proportional Share Allocation Systems is Useful ? Ion Stoica Hui Zhang y Kevin Jeffay z Abstract In the recent years, the proportional share schedulers have emerged as a viable alternative for...
Sanjoy Baruah, Steve Goddard, Kevin Jeffay
The Processing Graph Method (PGM)--- a dataflow model widely used in the design and analysis of embedded signal-processing applications--- is studied from a real-time scheduling perspective. It is...
A Patterned Injury Digital Library for Collaborative Forensic Medicine (2007)
Contact Information For, David Stotts, David Stotts, John Smith, Prasun Dewan, Kevin Jeffay, ...
this report to adequately outline our investigations in the user functions area.
Beyond Window Sharing Hacks: Support for First-Class Window Sharing (2007)
John Menges Kevin, Kevin Jeffay
Over the past 8 years there have been numerous attempts to develop add-ons to the X Window System that enable basic sharing of arbitrary X applications. These systems have never been much more than...
Early Experience with a Repository for Patterned Injury Data (2007)
David Stotts, John Smith, Kevin Jeffay, William Oliver, Prasun Dewan, Dana Smith
We have constructed a proof-of-principle system called the Repository for Patterned Injury Data (RPID) for supporting collaborative forensic medicine. The early RPID prototype is built on ABC/DGS, a...
A Patterned Injury Digital Library for Collaborative Forensic Medicine (2007)
David Stotts, David Stotts, John Smith, Prasun Dewan, Kevin Jeffay, F. Donalson Smith, ...
this report to adequately outline our investigations in the user functions area. The problem of different data types and formats being non-uniformly mixable in current hypermedia systems is being...
Efficient Object Sharing in Real-Time Systems (2007)
James H. Anderson, Srikanth Ramamurthy, Mark Moir, Kevin Jeffay
We show that, by rejecting a number of conventional assumptions about real-time object sharing, it is possible to develop and implement efficient object-sharing mechanisms on uniprocessors that do...
The Design, Implementation, and Use of a Sporadic Tasking Model (2007)
Kevin Jeffay, David Becker, David Bennett, Shaun Bharrat, Timothy Gramling, Mark Housel
: This paper describes the design, implementation, and use of a model of sporadic tasks in the Real-Time Mach kernel (MK83). This provides a programming model in real-Time Mach (RT-Mach) that is...
On the Partitioning of Function in Distributed Synchronous Collaboration Systems (2007)
A large number of experimental (and a few commercial) distributed synchronous collaboration support systems have been developed to date for the UNIX 1 /X environment. These systems typically fall...
Hussein Abdel-wahab, Kevin Jeffay, Sanjoy K. Baruah, Johannes E. Gehrke, C. Greg Plaxton
We propose and analyze a proportional share resource allocation algorithm for realizing real-time performance in time-shared operating systems. In a proportional share system, processes are assigned...
Responsive vs. Unresponsive Traffic: Active Queue Management for a Better-Than-BestEffort (2007)
Mark Parris, Kevin Jeffay, Don Smith
Abstract: In the best-effort Internet, there is a fundamental tension between responsive and unresponsive flows. During periods of congestion, responsive flows reduce the load they generate while...
Multimedia Networking Support for Distributed, Immersive Virtual Environments (2007)
Kevin Jeffay, Thomas Hudson, Mark Parris
Abstract: Like interactive audio/video applications, distributed virtual environments (DVEs) require continuous, lowlatency delivery of media. While end-system media adaptations and network-based...
On Inferring the Geographic Properties of the Internet (2007)
Lakshminarayanan Subramanian, Arvind Arasu, B. R. Badrinath, Mary Baker, Paul Barford, John Byers, ...
this paper to be affected by such failures since our measurements were spread over a 2-month time period. We use traceroute to determine the network path between 20 traceroute sources and thousands...
Multivariate SVD Analyses For Network Anomaly Detection (2005)
Jeff Terrell, Kevin Jeffay, F. Donelson Smith, Lingsong Zhang, Haipeng Shen, Zhengyuan Zhu, ...
We are investigating the use of signals analysis methods for near real-time anomaly and intrusion detection. Recently, methods such as wavelet analysis [1], and principle component analysis [2-4]...
Long Le, Jay Kikat, Kevin Jeffay, Don Smith, Feng Li
� The case for differential congestion notification (DCN). � A DCN prototype and its empirical evaluation. 2005-2-15 CS577(Spring 2005) 2 Router-Based Congestion Control The Case against...
Multivariate SVD Analyses For Network Anomaly Detection (2005)
Jeff Terrell, Kevin Jeffay, F. Donelson Smith, Lingsong Zhang, Haipeng Shen, Zhengyuan Zhu, ...
We are investigating the use of signal analysis methods for near real-time anomaly and intrusion detection. Recently, methods such as wavelet analysis [1] and principle component analysis [2-4] have...
Extremal dependence: Internet traffic applications. Stochastic Models (2005)
Felix Hernandez-campos, Kevin Jeffay
� For bivariate heavy tailed data, the extremes may carry distinctive dependence information not seen from moderate values. For example, a large value in one component may help cause a large value...
Long Le, Jay Aikat, Kevin Jeffay, F. Donelson Smith
We present an empirical study of the effects of active queue management (AQM) and explicit congestion notification (ECN) on the distribution of response times experienced by a population of users...
Stochastic Models for Generating Synthetic HTTP Source Traffic (2004)
Jin Cao, William S. Cleveland, Yuan Gao, Kevin Jeffay, F. Donelson Smith, Michele Weigle
New source-level models for aggregated HTTP traffic and a design for their integration with the TCP transport layer are built and validated using two large-scale collections of TCP/IP packet header...
Differential congestion notification: Taming the elephants (2004)
Long Le, Jay Aikat, Kevin Jeffay, F. Donelson Smith
Abstract — Active queue management (AQM) in routers has been proposed as a solution to some of the scalability issues associated with TCP’s pure end-to-end approach to congestion control. A...
Extremal dependence: Internet Traffic Applications (2004)
Felix Hernandez Campos, J. S. Marron, Sidney I. Resnick, Kevin Jeffay
For bivariate heavy tailed data, the extremes may carry distinctive dependence information not seen from moderate values. For example a large value in one component may help cause a large value in...
Extremal dependence: Internet Traffic Applications (2004)
Felix Hernandez Campos, J. S. Marron, Sidney I. Resnick, Cheolwoo Park, Kevin Jeffay
For bivariate heavy tailed data, the extremes may carry distinctive dependence information not seen from moderate values. For example a large value in one component may help cause a large value in...
Long Le, Jay Aikat, Kevin Jeffay, Don Smith
• State of the art in active queue management (AQM) – Control theoretic v.. traditional randomized dropping AQM • Do AQM schemes work? – An empirical study of the effect of AQM on web...
Quantifying the effects of recent protocol improvements to standards-track TCP (2003)
Michele C. Weigle, Kevin Jeffay, F. Donelson Smith
We assess the state of Internet congestion control and error recovery through a controlled study that considers the integration of standards-track TCP error recovery and both TCP and router-based...
Anand Srinivasan, James H. Anderson, Sanjoy K. Baruah, Kevin Jeffay, Reader Giorgio Buttazzo, Prasun Dewan, ...
Multiprocessors (Under the direction of James H. Anderson) Proportionate fair (Pfair) scheduling is the only known way to optimally schedule periodic real-time task systems on multiprocessors in an...
Quantifying the effects of recent protocol improvements to standards-track TCP (2003)
Michele C. Weigle, Kevin Jeffay, F. Donelson Smith
We assess the state-of-the-art in Internet congestion control and error recovery through a controlled study that considers the integration of standards-track TCP error recovery and both TCP and...
Tracking the evolution of Web traffic: 1995-2003 (2003)
Félix Hernández-campos, Kevin Jeffay, F. Donelson Smith
Understanding the nature and structure of web traffic is essential for valid simulations of networking technologies that affect the end-to-end performance of HTTP connections. We provide data...
The Effects of Active Queue Management on Web Performance (2003)
Long Le, Jay Aikat, Kevin Jeffay, F. Donelson Smith
We present an empirical study of the effects of active queue management (AQM) on the distribution of response times experienced by a population of web users. Three prominent AQM schemes are...
The Effects of AQM on Web Performance Outline (2003)
Long Le, Jay Aikat, Kevin Jeffay, Don Smith
•We We’ve ve conducted an empirical evaluation of the effects of three prominent AQM schemes … schemes –PI, PI, REM, and Adaptive/Gentle RED …on on the response time of web-like...
Tracking the evolution of Web traffic: 1995-2003 (2003)
Félix Hernández-campos, Kevin Jeffay, F. Donelson Smith
Understanding the nature and structure of web traffic is essential for valid simulations of networking technologies that affect the end-to-end performance of HTTP connections. We provide data...
Tracking the evolution of Web traffic: 1995-2003 (2003)
Félix Hernández-campos, Kevin Jeffay, F. Donelson Smith
Understanding the nature and structure of web traffic is essential for valid simulations of networking technologies that affect the end-to-end performance of HTTP connections. We provide data...
Tracking the evolution of Web traffic: 1995-2003 (2003)
Félix Hernández-campos, Kevin Jeffay, F. Donelson Smith
Understanding the nature and structure of web traffic is essential for valid simulations of networking technologies that affect the end-to-end performance of HTTP connections. We provide data...
Statistical clustering of internet communication patterns (2003)
Félix Hernández-campos, F. Donelson Smith, Kevin Jeffay, Andrew B. Nobel
We describe a new methodology for analyzing Internet traffic based on an abstract model of application-level communication and statistical cluster analysis, and argue that this method of analysis can...
Statistical clustering of internet communication patterns (2003)
Félix Hernández-campos, F. Donelson Smith, Kevin Jeffay, Andrew B. Nobel
We describe a new methodology for analyzing Internet traffic based on an abstract model of application-level communication and statistical cluster analysis, and argue that this method of analysis can...
Long Le, Jay Aikat, Kevin Jeffay, Don Smith
• State of the art in active queue management (AQM) – Control theoretic v.. traditional randomized dropping AQM • Do AQM schemes work? – An empirical study of the effect of AQM on web...
Quantifying the effects of recent protocol improvements to standards-track TCP (2003)
Michele C. Weigle, Kevin Jeffay, F. Donelson Smith
We assess the state-of-the-art in Internet congestion control and error recovery through a controlled study that considers the integration of standards-track TCP error recovery and both TCP and...
RATE r Sender Receiver Sender (2003)
Long Le, Jay Aikat, Kevin Jeffay, Don Smith
• State of the art in active queue management (AQM) – Control theoretic v.. traditional randomized dropping AQM • Do AQM schemes work? – An empirical study of the effect of AQM on web...
What TCP/IP protocol headers can tell us about the web (2001)
F. Donelson Smith, Félix Hernández Campos, Kevin Jeffay, David Ott
We report the results of a large-scale empirical study of web traffic. Our study is based on over 500 GB of TCP/IP protocolheader traces collected in 1999 and 2000 (approximately one year apart) from...
What TCP/IP protocol headers can tell us about the web (2001)
F. Donelson Smith, Félix Hernández Campos, Kevin Jeffay, David Ott
We report the results of a large-scale empirical study of web traffic. Our study is based on over 500 GB of TCP/IP protocolheader traces collected in 1999 and 2000 (approximately one year apart) from...
Rate-based resource allocation models for embedded systems (2001)
Abstract: Run-time executives and operating system kernels for embedded systems have long relied exclusively on static priority scheduling of tasks to ensure timing constraints and other correctness...
What Tcp Ip, F. Donelson Smith, Félix Hernández Campos, Kevin Jeffay, David Ott
We report the results of a large-scale empirical study of web traffic. Our study is based on over 500 GB of TCP/IP protocolheader traces collected in 1999 and 2000 (approximately one year apart) from...
Rate-based resource allocation models for embedded systems (2001)
Abstract: Run-time executives and operating system kernels for embedded systems have long relied exclusively on static priority scheduling of tasks to ensure timing constraints and other correctness...
Kevin Jeffay, Thomas Hudson, Mark Parris
Abstract: Like interactive audio/video applications, distributed virtual environments (DVEs) require continuous, lowlatency delivery of media. While end-system media adaptations and network-based...
Rate-based resource allocation models for embedded systems (2001)
Abstract. Run-time executives and operating system kernels for embedded systems have long relied exclusively on static priority scheduling of tasks to ensure timing constraints and other correctness...
Managing Latency and Buffer Requirements in Processing Graph Chains (2001)
Real-time signal-processing applications for high assurance systems are commonly designed using a processing-graph software architecture. Here we demonstrate the management of latency and buffer...
Tuning RED for Web Traffic (2000)
Mikkel Christiansen, Kevin Jeffay, David Ott, F. Donelson Smith
We study the effects of RED on the performance of Web browsing with a novel aspect of our work being the use of a usercentric measure of performance — response time for HTTP request-response pairs....
Tuning RED for Web Traffic (2000)
Mikkel Christiansen, Kevin Jeffay, David Ott, F. Donelson Smith
Abstract * ** We study the effects of RED on the performance of Web browsing with a novel aspect of our work being the use of a usercentric measure of performance — response time for HTTP...
Tuning RED for Web Traffic (2000)
Mikkel Christiansen, Kevin Jeffay, David Ott, F. Donelson Smith
We study the effects of RED on the performance of Web browsing with a novel aspect of our work being the use of a usercentric measure of performance--- response time for HTTP request-response pairs....
Tuning RED for Web Traffic (2000)
Mikkel Christiansen, Kevin Jeffay, David Ott, F. Donelson Smith
We study the effects of RED on the performance of Web browsing with a novel aspect of our work being the use of a usercentric measure of performance--- response time for HTTP request-response pairs....
Kevin Jeffay, Gerardo Lamastra
: Scheduling architectures that support a rate abstraction are becoming increasingly popular for realizing real-time services in general-purpose operating systems. While many rate-based schemes have...
Tuning RED for Web Traffic (2000)
Mikkel Christiansen, Kevin Jeffay, David Ott, F. Donelson Smith
We study the effects of RED on the performance of Web browsing with a novel aspect of our work being the use of a usercentric measure of performance — response time for HTTP request-response pairs....
Tuning RED for Web Traffic (2000)
Mikkel Christiansen, Kevin Jeffay, David Ott, F. Donelson Smith
We study the effects of RED on the performance of Web browsing with a novel aspect of our work being the use of a usercentric measure of performance — response time for HTTP request-response pairs....
Tuning RED for Web Traffic (2000)
Mikkel Christiansen, Kevin Jeffay, David Ott, F. Donelson Smith
Abstract * ** We study the effects of RED on the performance of Web browsing with a novel aspect of our work being the use of a usercentric measure of performance — response time for HTTP...
Abstract: Scheduling architectures that support a rate abstraction are becoming increasingly popular for realizing real-time services in general-purpose operating systems. While many rate-based...
Tuning RED for Web Traffic (2000)
Mikkel Christiansen, Kevin Jeffay, David Ott, F. Donelson Smith
We study the effects of RED on the performance of Web browsing with a novel aspect of our work being the use of a usercentric measure of performance — response time for HTTP request-response pairs....
The Synthesis of Real-Time Systems from Processing Graphs (2000)
Directed graphs, called processing graphs, are a standard design aid for complex real-time systems. The primary problem in developing real-time systems with processing graphs is transforming the...
The Rate-Based Execution Model (1999)
We present a new task model for the real-time execution of event-driven tasks in which no a priori characterization of the actual arrival rates of events is known; only the expected arrival rates of...
Analyzing the real-time properties of a U.S. navy signal processing system (1999)
The state of the art in verifying the real-time requirements of applications developed using general processing graph models relies on simulation or off-line scheduling. We extend the state of the...
Towards a Better-Than-Best-Effort Forwarding Service for Multimedia Flows (1999)
Our research at UNC concerns the management of multimedia and more general continuous-media flows across the Internet. We focus on network support for (highly) interactive applications where...
Analyzing the real-time properties of a U.S. navy signal processing system (1999)
The state of the art in verifying the real-time requirements of applications developed using general processing graph models relies on simulation or off-line scheduling. We extend the state of the...
Lightweight Active Router-Queue Management for Multimedia Networking (1999)
Mark Parris, Kevin Jeffay, F. Donelson Smith
The Internet research community is promoting active queue management in routers as a proactive means of addressing congestion in the Internet. Active queue management mechanisms such as Random Early...
The Rate-Based Execution Model (1999)
We present a new task model for the real-time execution of event-driven tasks in which no a priori characterization of the actual arrival rates of events is known; only the expected arrival rates of...
A Theory of Rate-Based Execution (1999)
* We present a task model for the real-time execution of eventdriven tasks in which no a priori characterization of the actual arrival rates of events is known; only the expected arrival rates of...
Parallel Switching in Connection-Oriented Networks (1999)
James Anderson, Sanjoy Baruah, Kevin Jeffay
Packet switching in connection-oriented networks that may have multiple parallel links between pairs of switches is considered. An efficient packet-scheduling algorithm that guarantees a...
Lightweight Active Router-Queue Management for Multimedia Networking (1999)
Mark Parris, Kevin Jeffay, F. Donelson Smith
The Internet research community is promoting active queue management in routers as a proactive means of addressing congestion in the Internet. Active queue management mechanisms such as Random Early...
Application-Level Measurements of Performance on the vBNS (1999)
* We examine the performance of high-bandwidth multimedia applications over high-speed wide-area networks, such as the vBNS (Internet2). We simulate a teleimmersion application that sends 30 Mbps...
Lightweight Active Router-Queue Management for Multimedia Networking (1999)
Mark Parris, Kevin Jeffay, F. Donelson Smith
The Internet research community is promoting active queue management in routers as a proactive means of addressing congestion in the Internet. Active queue management mechanisms such as Random Early...
Scheduling Sporadic Tasks with Shared Resources in Hard-Real-Time Systems. (1998)
We consider a characterization of a real time system consisting as a set of sporadic tasks that share a set of serially reusable, single unit resources. Sporadic tasks are a generalization of...
One component of this project is the construction of a distributed, real time, video conferencing system on a network of high performance workstations. This note concerns the technological issues...
Efficient object sharing in quantum-based real-time systems (1998)
James H. Anderson, Rohit Jain, Kevin Jeffay
The authors present a new scheme for implementing shared objects on a real-time system [1]. They assume that the system allocates processor time in discrete quanta, and that the quantum is large...
Proportional share scheduling of operating system services for real-time applications (1998)
Kevin Jeffay, F. Donelson Smith, Arun Moorthy, James Anderson
Abstract * While there is currently great interest in the problem of providing real-time services in general purpose operating systems, the issue of real-time scheduling of internal operating system...
Proportional share scheduling of operating system services for real-time applications (1998)
Kevin Jeffay, F. Donelson Smith, Arun Moorthy, James Anderson
Abstract * While there is currently great interest in the problem of providing real-time services in general purpose operating systems, the issue of real-time scheduling of internal operating system...
A betterthan-best-effort service for continuous media udp flows (1998)
Mark Parris, Kevin Jeffay, F. Donelson, Smith Jan Borgersen
The Internet community is very interested in addressing congestion with active queue management mechanisms like Random Early Detection (RED). Recent proposals extend these mechanisms to actively...
A Software Synthesis Method for Building Real-Time Systems from Processing Graphs (1998)
Embedded signal processing applications are commonly designed using a processing graph software architecture. Unfortunately, existing technology does not support mapping general processing graphs to...
A Better-Than-Best-Effort Service for Continuous Media UDP Flows (1998)
Mark Parris, Kevin Jeffay, F. Donelson, Smith Jan Borgersen
The Internet community is very interested in addressing congestion with active queue management mechanisms like Random Early Detection (RED). Recent proposals extend these mechanisms to actively...
Efficient Object Sharing in Quantum-Based Real-Time Systems (1998)
James Anderson, Rohit Jain, Kevin Jeffay
We consider the problem of implementing shared objects in uniprocessor and multiprocessor real-time systems in which tasks are executed using a scheduling quantum. In most quantum-based systems, the...
Proportional Share Scheduling of Operating System Services for Real-Time Applications (1998)
Kevin Jeffay, F. Donelson Smith, Arun Moorthy, James Anderson
* While there is currently great interest in the problem of providing real-time services in general purpose operating systems, the issue of real-time scheduling of internal operating system...
Efficient Object Sharing in Quantum-Based Real-Time Systems (1998)
James H. Anderson, Rohit Jain, Kevin Jeffay
We consider the problem of implementing shared objects in uniprocessor and multiprocessor real-time systems in which tasks are executed using a scheduling quantum. In most quantum-based systems, the...
Managing Memory Requirements in the Synthesis of Real-Time Systems from Processing Graphs (1998)
In the past, environmental restrictions on size, weight, and power consumption have severely limited both the processing and storage capacity of embedded signal processing systems. Today, however, as...
A Better-Than-Best-Effort Service for Continuous Media UDP (1998)
Flows Mark, Mark Parris, Kevin Jeffay, F. Donelson, Smith Jan Borgersen
The Internet community is very interested in addressing congestion with active queue management mechanisms like Random Early Detection (RED). Recent proposals extend these mechanisms to actively...
Proportional Share Scheduling of Operating System Services for Real-Time Applications (1998)
Kevin Jeffay, F. Donelson Smith, Arun Moorthy, James Anderson
While there is currently great interest in the problem of providing real-time services in general purpose operating systems, the issue of real-time scheduling of internal operating system activities...
A Software Synthesis Method for Building Real-Time Systems from Processing Graphs (1998)
In this paper, we present software synthesis techniques that create a real-time uniprocessor system from processing graphs. To achieve the synthesis, new rate theorems have been developed to derive...
A betterthan-best-effort service for continuous media udp flows (1998)
Mark Parris, Kevin Jeffay, F. Donelson, Smith Jan Borgersen
The Internet community is very interested in addressing congestion with active queue management mechanisms like Random Early Detection (RED). Recent proposals extend these mechanisms to actively...
Proportional share scheduling of operating system services for real-time applications (1998)
Kevin Jeffay, F. Donelson Smith, Arun Moorthy, James Anderson
Abstract * While there is currently great interest in the problem of providing real-time services in general purpose operating systems, the issue of real-time scheduling of internal operating system...
Proportional share scheduling of operating system services for real-time applications (1998)
Kevin Jeffay, F. Donelson Smith, Arun Moorthy, James Anderson
Abstract * While there is currently great interest in the problem of providing real-time services in general purpose operating systems, the issue of real-time scheduling of internal operating system...
On the Duality between Resource Reservation and Proportional Share Resource Allocation (1997)
Hussein Abdel-wahab, Kevin Jeffay
We describe a new framework for resource allocation that unifies the well-known proportional share and resource reservation policies. Each client is characterized by two parameters: a weight that...
The Performance of Two-Dimensional Media Scaling for Internet Videoconferencing (1997)
Peter Nee Kevin, Kevin Jeffay, Gunner Danneels
: Until mechanisms for true real-time network communications are deployed and pervasive, one must rely on adaptive, best-effort congestion control methods to provide acceptable levels of service for...
Lock-Free Transactions for Real-Time Systems (1997)
James H. Anderson, Srikanth Ramamurthy, Mark Moir, Kevin Jeffay, Kevin Je Ay
We show that previous algorithmic and scheduling work concerning the use of lock-free objects in hard real-time systems can be extended to support real-time transactions on memory-resident data....
Real-time signal processing applications arecommonly designed using a data#ow softwarearchitecture. Here we attempt to understand fundamental real-time properties of such an architecture --- the...
Lock-Free Transactions for Real-Time Systems (1997)
James Anderson, Srikanth Ramamurthy, Mark Moir, Kevin Jeffay
INTRODUCTION Lock-free objects are an alternative to lock-based object sharing protocols such as the priority ceiling protocol [17, 21] in preemptive real-time uniprocessor systems. An object...
Real-Time Computing with Lock-Free Shared Objects (1997)
James Anderson, Srikanth Ramamurthy, Kevin Jeffay
This paper considers the use of lock-free shared objects within hard real-time systems. As the name suggests,...
Real-Time Computing with Lock-Free Shared Objects (1997)
James Anderson, Srikanth Ramamurthy, Kevin Jeffay
ing with credit is permitted. To copy otherwise, to republish, to post on servers, to redistribute to lists, or to use any component of this work in other works, requires prior speci#c permission...
Lock-Free Transactions for Real-Time Systems (1997)
James H. Anderson, Srikanth Ramamurthy, Mark Moir, Kevin Jeffay
We show that previous algorithmic and scheduling work concerning the use of lock-free objects in hard real-time systems can be extended to support real-time transactions on memory-resident data....
On the Duality between Resource Reservation and Proportional Share Resource Allocation (1997)
Ion Stoica, Hussein Abdel-wahab, Kevin Jeffay
We describe a new framework for resource allocation that unifies the well-known proportional share and resource reservation policies. Each client is characterized by two parameters: a weight that...
A Two-Dimensional Audio Scaling Enhancement to an Internet Videoconferencing System (1997)
Peter Nee, Kevin Jeffay, Michele Clark, Gunnar Danneels
: Without widely deployed mechanisms for resource reservation, adaptive, best-effort techniques are the only methods of congestion control available to interactive, real-time applications. Here we...
The Performance of Two-Dimensional Media Scaling for Internet Videoconferencing (1997)
Peter Nee, Kevin Jeffay, Gunnar Danneels
: Until mechanisms for true real-time network communications are deployed and pervasive, one must rely on adaptive, best-effort congestion control methods to provide acceptable levels of service for...
Real-time signal processing applications are commonly designed using a dataflow software architecture. Here we attempt to understand fundamental real-time properties of such an architecture --- the...
Real-time signal processing applications are commonly designed using a dataflow software architecture. Here we attempt to understand fundamental real-time properties of such an architecture --- the...
Feasibility concerns in PGM graphs with bounded buffers (1997)
Sanjoy Baruah, Steve Goddard, Kevin Jeffay
The Processing Graph Method (PGM) --- a dataflow model widely used in the design and analysis of embedded signal-processing applications --- is studied from a real-time scheduling perspective. It is...
Design Principles for Distributed, Interactive, Virtual Environments (1997)
Kevin Jeffay, Gary Bishop, James H. Anderson, Richard Superfine, ...
this document we often use the terms interchangeably.
Lock-Free Transactions for Real-Time Systems (1997)
James H. Anderson, Srikanth Ramamurthy, Mark Moir, Kevin Jeffay
We show that previous algorithmic and scheduling work concerning the use of lock-free objects in hard real-time systems can be extended to support real-time transactions on memory-resident data....
Lock-Free Transactions for Real-Time Systems (1997)
James H. Anderson, Srikanth Ramamurthy, Mark Moir, Kevin Jeffay
We show that previous algorithmic and scheduling work concerning the use of lock-free objects in hard real-time systems can be extended to support real-time transactions on memory-resident data....
Feasibility concerns in PGM graphs with bounded buffers (1997)
Sanjoy Baruah, Steve Goddard, Kevin Jeffay
The Processing Graph Method (PGM) -- a dataflow model widely used in the design and analysis of embedded signal-processing applications -- is studied from a real-time scheduling perspective. It is...
Real-time computing with lock-free shared objects (1997)
James H. Anderson, Srikanth Ramamurthy, Kevin Jeffay
This paper considers the use of lock-free shared objects within hard real-time systems. As the name suggests, lock-free shared objects are distinguished by the fact that they are accessed without...
On the Duality between Resource Reservation and Proportional Share Resource Allocation (1997)
Ion Stoica, Hussein Abdel-wahab, Kevin Jeffay
We describe a new framework for resource allocation that unifies the well-known proportional share and resource reservation policies. Each client is characterized by two parameters: a weight that...
Srikanth Ramamurthy, Prof James Anderson, Adviser Prof, Prasun Dewan, Reader Prof, Kevin Jeffay
This work aims to establish the viability of lock-free object sharing in uniprocessor real-time systems. Naive usage of conventional lock-based object-sharing schemes in realtime systems leads to...
A Proportional Share Resource Allocation Algorithm For Real-Time, Time-Shared Systems (1996)
Ion Stoica, Hussein Abdel-wahab, Kevin Jeffay, Sanjoy K. Baruah, Johannes E. Gehrke, C. Greg Plaxton
We propose and analyze a proportional share resource allocation algorithm for realizing real-time performance in time-shared operating systems. In a proportional share system, processes are assigned...
A Proportional Share Resource Allocation Algorithm for Real-Time, Time-Shared Systems (1996)
Ion Stoica, Hussein Abdel-wahab, Kevin Jeffay, Sanjoy K. Baruah, Johannes E. Gehrke, C. Greg Plaxton
We propose and analyze a proportional share resource allocation algorithm for realizing real-time performance in time-shared operating systems. Processes are assigned a weight which determines a...
Fair On-Line Scheduling of a Dynamic Set of Tasks on a Single Resource (1996)
Sanjoy K. Baruah, Johannes E. Gehrke, C. Greg Plaxton, Ion Stoica, Hussein Abdel-wahab, Kevin Jeffay
Consider a set of "tasks" competing for the use of a single "resource", where: (i) only one task is allowed to use the resource at a time, (ii) the resource is scheduled in...
A Router-Based Congestion Control Scheme for Real-Time Continuous Media (1996)
Kevin Jeffay, Mark Parris, F. Donelson, Smith Terry, M. Talley
: Many distributed multimedia applications require real-time network communication services to be effective. Although architectural models for real-time communication on the Internet are evolving...
Fair On-Line Scheduling of a Dynamic Set of Tasks on a Single Resource (1996)
Sanjoy K. Baruah, Johannes E. Gehrke, C. Greg Plaxton, Ion Stoica, Hussein Abdel-wahab, ...
Consider a set of "tasks" competing for the use of a single "resource", where: (i) only one task is allowed to use the resource at a time, (ii) the resource is scheduled in...
A Proportional Share Resource Allocation Algorithm for Real-Time, Time-Shared Systems (1996)
Ion Stoica, Hussein Abdel-wahab, Kevin Jeffay, Sanjoy K. Baruah, Johannes E. Gehrke, C. Greg Plaxton
We propose and analyze a proportional share resource allocation algorithm for realizing real-time performance in time-shared operating systems. Processes are assigned a weight which determines a...
A General Framework for Continuous Media Transmission Control (1996)
: One of the major problems experienced with LAN-based video conferencing systems is the degradation of conference latency and fidelity due to network congestion. In this paper, we present a...
A Proportional Share Resource Allocation Algorithm For Real-Time, Time-Shared Systems (1996)
Ion Stoica, Hussein Abdel-wahab, Kevin Jeffay, Sanjoy K. Baruah, Johannes E. Gehrke, C. Greg Plaxton
We propose and analyze a proportional share resource allocation algorithm for realizing real-time performance in time-shared operating systems. In a proportional share system, processes are assigned...
A Router-Based Congestion Control Scheme For Real-Time Continuous (1996)
Kevin Jeffay, Mark Parris, F. Donelson, Smith Terry, M. Talley
Abstract: Many distributed multimedia applications require real-time network communication services to be effective. Although architectural models for real-time communication on the Internet are...
A rate-based execution abstraction for multimedia computing (1995)
{jeffay, bennettd} @ cs. unc. edu Abstract: Process models for multimedia computing must allow applications to adapt their pattern of execution as resources become scarce or abundant. As processes...
A rate-based execution abstraction for multimedia computing (1995)
{jeffay, bennettd} @ cs. unc. edu Abstract: Process models for multimedia computing must allow applications to adapt their pattern of execution as resources become scarce or abundant. As processes...
Predicting Worst Case Execution Times on a Pipelined RISC Processor (1995)
Shaun J. Bharrat, Kevin Jeffay
: A key step in analyzing and reasoning about the performance of realtime systems is the derivation of the worst case execution time of a program or program fragment. Modern computer systems with...
Real-Time Computing with Lock-Free Shared Objects (1995)
James H. Anderson, Srikanth Ramamurthy, Kevin Jeffay
This paper considers the use of lock-free shared objects within hard real-time systems. As the name suggests, lock-free shared objects are distinguished by the fact that they are not locked. As such,...
Real-Time Computing with Lock-Free Shared Objects (1995)
James H. Anderson, Srikanth Ramamurthy, Kevin Jeffay
This paper considers the use of lock-free shared objects within hard real-time systems. As the name suggests, lock-free shared objects are distinguished by the fact that they are not locked. As such,...
Real-Time Computing with Lock-Free Shared Objects (1995)
James Anderson Srikanth, James H. Anderson, Srikanth Ramamurthy, Kevin Jeffay
This paper considers the use of lock-free shared objects within hard real-time systems. As the name suggests, lock-free shared objects are distinguished by the fact that they are not locked. As such,...
Early Prototypes of the Repository for Patterned Injury Data (1995)
Prasun Dewan Kevin, Kevin Jeffay, William Oliver
We have constructed a proof-of-principle system for supporting collaborative forensic medicine. The early prototype is built on ABC/DGS, a graph-server and collaborative hypermedia system built in...
Real-Time Computing with Lock-Free Shared Objects (1995)
James Anderson, Srikanth Ramamurthy, Kevin Jeffay
This paper considers the use of lock-free shared objects within hard real-time systems. As the name suggests, lock-free shared objects are distinguished by the fact that they are not locked. As such,...
An Empirical Study of Delay Jitter Management Policies (1995)
: This paper presents an empirical study of several policies for managing the effect of delay jitter on the playout of audio and video in computer-based conferences. The problem addressed is that of...
Early Prototypes of the Repository for Patterned Injury Data (1995)
Prasun Dewan, Kevin Jeffay, John Smith, David Stotts, William Oliver
We have constructed a proof-of-principle system for supporting collaborative forensic medicine. The early prototype is built on ABC/DGS, a graph-server and collaborative hypermedia system built in...
Real-Time Computing with Lock-Free Shared Objects (1995)
James Anderson, Srikanth Ramamurthy, Kevin Jeffay
ing with credit is permitted. To copy otherwise, to republish, to post on servers, to redistribute to lists, or to use any component of this work in other works, requires prior specific permission...
Gregory Bollella, Kevin Jeffay
: Distributed multimedia applications are typical of a new class of workstation applications that require realtime communication and computation services to be effective. Unfortunately, there remains...
Real-Time Computing with Lock-Free Shared Objects (1995)
James Anderson, Srikanth Ramamurthy, Kevin Jeffay
This paper considers the use of lock-free shared objects within hard real-time systems. As the name suggests, lock-free shared objects are distinguished by the fact that they are not locked. As such,...
Early Prototypes of the Repository for Patterned Injury Data (1995)
Prasun Dewan, Kevin Jeffay, John Smith, David Stotts, William Oliver
We have constructed a proof-of-principle system for supporting collaborative forensic medicine. The early prototype is built on ABC/DGS, a graph-server and collaborative hypermedia system built in...
A rate-based execution abstraction for multimedia computing (1995)
Abstract: Process models for multimedia computing must allow applications to adapt their pattern of execution as resources become scarce or abundant. As processes adapt, it is natural to express...
An Empirical Study of Delay Jitter Management Policies (1995)
Abstract: This paper presents an empirical study of several policies for managing the effect of delay jitter on the playout of audio and video in computer-based conferences. The problem addressed is...
On Latency Management in Time-Shared Operating Systems (1994)
: The design of general purpose operating systems impose constraints on the way one can structure real-time applications. This paper addresses the problem of minimizing the end-to-end latency of...
A Patterned Injury Digital Library for Collaborative Forensic Medicine (1994)
David Stotts, John Smith, Prasun Dewan, Kevin Jeffay, F. Donalson Smith, Dana Smith, ...
The UNC CS Collaboratory, in conjunction with the Armed Forces Institute of Pathology and the Office of the North Carolina Chief Medical Examiner, is constructing a digital library to augment the...
Queue Monitoring - A Delay Jitter Management Policy (1994)
: This paper describes queue monitoring, a policy for managing the effect of delay jitter on audio and video in computer-based conferences. By observing delay jitter over time, this policy...
Inverting X: An Architecture for a Shared Distributed Window System (1994)
: Shared window systems have become a popular vehicle for supporting distributed, synchronous collaboration. At present they are difficult to build and they support limited paradigms of multi-user...
Adaptive, Best-Effort Delivery Of Audio And Video Across Packet-Switched Networks (1994)
Kevin Jeffay Donald L. Stone University of North Carolina at Chapel Hill Department of Computer Science Chapel Hill, NC 27599-3175 {jeffay,stone}@cs.unc.edu INTRODUCTION This videotape is a...
A Patterned Injury Digital Library for Collaborative Forensic Medicine (1994)
David Stotts, John Smith, Prasun Dewan, Kevin Jeffay, F. Donalson Smith, Dana Smith, ...
The UNC CS Collaboratory, in conjunction with the Armed Forces Institute of Pathology and the Office of the North Carolina Chief Medical Examiner, is constructing a digital library to augment the...
Issues, Problems and Solutions in Sharing X Clients on Multiple Displays (1994)
Hussein Abdel-wahab, Kevin Jeffay
This paper describes the salient problems that face the designers of X-based shared window systems and provides solutions and implementation principles for addressing the problems. The enumeration of...
Issues, Problems and Solutions in Sharing X Clients on Multiple Displays (1994)
Hussein Abdel-wahab, Kevin Jeffay
Many computer conferencing systems based on the X Window System have recently emerged. While these systems hold the promise for fostering collaboration among groups of geographically separated...
A Delay Jitter Management Policy (1993)
Donald Stone Kevin, Kevin Jeffay
: This paper describes queue monitoring, a policy for managing the effect of delay jitter on audio and video in computer-based conferences. By observing delay jitter over time, this policy...
: A concurrent programming system for constructing hard-real-time applications is described. The system is based on a novel semantics of inter-process communication called the real-time...
Accounting for Interrupt Handling Costs in Dynamic Priority Task Systems (1993)
: In order to apply the results of formal studies of real-time task models, a practitioner must account for the effects of phenomena present in the implementation but not present in the formal model....
Accommodating Latecomers in Shared Window Systems (1993)
Goopeel Chung, Goopeel Chung, Kevin Jeffay, Kevin Jeffay, Hussein Abdel-wahab, Hussein Abdel-wahab
A viable concurrent engineering environment should support synchronous collaboration among distributed users. Shared window systems provide this support by allowing multiple users to create...
Scheduling Sporadic Tasks with Shared Resources in Hard-Real-Time Systems (1992)
The problem of scheduling a set of sporadic tasks that share a set of serially reusable, single unit software resources on a single processor is considered. The correctness conditions are that (1)...
YARTOS Kernel support for efficient, predictable real-time systems (1992)
Kevin Jeffay, Donald L. Stone, Daniel E. Poirier
. YARTOS is an experimental real-time operating system kernel that provides guaranteed response times to tasks. It is currently used as a vehicle for research in the design, analysis, and...
On Kernel Support for Real-Time Multimedia Applications (1992)
: Real-time operating system services are required to support multimedia systems that rely heavily of the workstation processor for control of the audio and video processors and movement of audio and...
Kernel support for live digital audio and video (1992)
Kevin Jeffay, Donald L. Stone, F. Donelson Smith
Abstract: We have developed a real-time operating system kernel which has been used to support the transmission and reception of streams of live digital audio and video in real-time as part of a...
Yartos: Kernel support for efficient, predictable real-time systems (1992)
Kevin Jeffay, Donald L. Stone, Daniel E. Poirier
Abstract. YARTOS is an experimental real-time operating system kernel that provides guaranteed response times to tasks. It is currently used as a vehicle for research in the design, analysis, and...
On kernel support for real-time multimedia applications (1992)
Abstract: Real-time operating system services are required to support multimedia systems that rely heavily of the workstation processor for control of the audio and video processors and movement of...
On non-preemptive scheduling of periodic and sporadic tasks (1991)
Kevin Jeffay, Donald F. Stanat
Abstract: This paper examines a fundamental problem in the theory of real-time scheduling, that of scheduling a set of periodic or sporadic tasks on a uniprocessor without preemption and without...
On Non-Preemptive Scheduling of Periodic and Sporadic Tasks (1991)
Kevin Jeffay, Donald F. Stanat, Charles U. Martel
: This paper examines a fundamental problem in the theory of real-time scheduling, that of scheduling a set of periodic or sporadic tasks on a uniprocessor without preemption and without inserted...
An Implementation and Application of the RealTime Producer/Consumer Paradigm (1990)
: We have created an efficient prototype implementation of the RealTime Producer/Consumer Paradigm, allowing us to build multiprograms within a Unix 1 process. We present a brief introduction to the...
An implementation and application of the real-time producer/consumer paradigm (1990)
Abstract: We have created an efficient prototype implementation of the Real-Time Producer/Consumer Paradigm, allowing us to build multiprograms within a Unix 1 process. We present a brief...
Abstract: This paper examines the problem of guaranteeing response times, on a uniprocessor, to sporadic tasks with preemption constraints. The preemption constraints arise from the fact that tasks...