Search For:

Displaying 1-31 out of 31 total
Real-Rate Scheduling
Found in: Real-Time and Embedded Technology and Applications Symposium, IEEE
By Ashvin Goel, Jonathan Walpole, Molly Shor
Issue Date:May 2004
pp. 434
Traditionally, real-time scheduling mechanisms have been used to provide predictable scheduling latency but these mechanisms are difficult to use in general-purpose operating systems (OSs) because they require precise specification of thread requirements i...
 
User-Level Implementations of Read-Copy Update
Found in: IEEE Transactions on Parallel and Distributed Systems
By Mathieu Desnoyers,Paul E. McKenney,Alan S. Stern,Michel R. Dagenais,Jonathan Walpole
Issue Date:February 2012
pp. 375-382
Read-copy update (RCU) is a synchronization technique that often replaces reader-writer locking because RCU's read-side primitives are both wait-free and an order of magnitude faster than uncontended locking. Although RCU updates are relatively heavy weigh...
 
Forensix: A Robust, High-Performance Reconstruction System
Found in: Distributed Computing Systems Workshops, International Conference on
By Ashvin Goel, Wu-chang Feng, David Maier, Wu-chi Feng, Jonathan Walpole
Issue Date:June 2005
pp. 155-162
<p>When computer intrusions occur, one of the most costly, time-consuming, and human-intensive tasks is the analysis and recovery of the compromised system. At a time when the cost of human resources dominates the cost of CPU, network, and storage re...
 
Infopipes: The ISL/ISG Implementation Evaluation
Found in: Network Computing and Applications, IEEE International Symposium on
By Galen Swint, Calton Pu, Younggyun Koh, Ling Liu, Wenchang Yan, Charles Consel, Koichi Moriyama, Jonathan Walpole
Issue Date:September 2004
pp. 293-296
We provide a performance comparison of generated Infopipes that have been translate the Spi/XIP variant of Infopipe specification into executable code. Infopipes are an abstraction to support information flow applications. These tools are evaluated through...
 
Storage System Support for Continuous-Media Applications, Part 1: Requirements and Single-Disk Issues
Found in: IEEE Distributed Systems Online
By Pål Halvorsen, Carsten Griwodz, Vera Goebel, Ketil Lund, Thomas Plagemann, Jonathan Walpole
Issue Date:February 2004
pp. 1
<p>To meet multimedia servers' increasing performance and scalability requirements, researchers must design multimedia storage system components that adapt to various workloads and requirements. They must also develop strategies for combining compone...
 
Storage System Support for Continuous-Media Applications, Part 1: Requirements and Single-Disk Issues
Found in: IEEE Distributed Systems Online
By Pål Halvorsen, Carsten Griwodz, Vera Goebel, Ketil Lund, Thomas Plagemann, Jonathan Walpole
Issue Date:January 2004
pp. 1
<p>A multimedia storage system plays a vital role for the performance and scalability of multimedia servers. To handle the server load imposed by increased user access to on-demand multimedia streaming applications, new storage system solutions are n...
 
Buffer Overflows: Attacks and Defenses for the Vulnerability of the Decade
Found in: Foundations of Intrusion Tolerant Systems
By Crispin Cowan, Perry Wagle, Calton Pu, Steve Beattie, Jonathan Walpole
Issue Date:December 2003
pp. 227
Buffer overflows have been the most common form of security vulnerability for the last ten years. More over, buffer overflow vulnerabilities dominate the area of remote network penetration vulnerabilities, where an anonymous Internet user seeks to gain par...
 
Analysis of a Reservation-Based Feedback Scheduler
Found in: Real-Time Systems Symposium, IEEE International
By Luca Abeni, Luigi Palopoli, Giuseppe Lipari, Jonathan Walpole
Issue Date:December 2002
pp. 71
When executing soft real-time tasks in a shared processor, it is important to properly allocate the computational resources such that the quality of service requirements of each task are satisfied. In this paper we propose Adaptive Reservations, based on a...
 
A Measurement-Based Analysis of the Real-Time Performance of Linux
Found in: Real-Time and Embedded Technology and Applications Symposium, IEEE
By Luca Abeni, Ashvin Goel, Charles Krasic, Jim Snow, Jonathan Walpole
Issue Date:September 2002
pp. 133
This paper presents an experimental study of the latency behavior of the Linux OS. We identify major sources of latency in the kernel with the goal of providing real-time performance in a widely used general-purpose operating system. We quantify each sourc...
 
Buffer Overflows: Attacks and Defenses for the Vulnerability of the Decade
Found in: DARPA Information Survivability Conference and Exposition,
By Crispin Cowan, Perry Wagle, Calton Pu, Steve Beattie, Jonathan Walpole
Issue Date:January 2000
pp. 1119
Buffer overflows have been the most common form of security vulnerability for the last ten years. More over, buffer overflow vulnerabilities dominate the area of remote network penetration vulnerabilities, where an anonymous Internet user seeks to gain par...
 
Constrained-Latency Storage Access
Found in: Computer
By Richard Staehli, Jonathan Walpole
Issue Date:March 1993
pp. 44-53
<p>A class of constrained-latency storage access (CLSA) applications that require both large amounts of storage and guarantees for short latencies are presented. A range of existing approaches to meeting the requirements of CLSA applications is surve...
 
Adaptive Live Video Streaming by Priority Drop
Found in: Advanced Video and Signal Based Surveillance, IEEE Conference on
By Jie Huang, Charles Krasic, Jonathan Walpole, Wu-chi Feng
Issue Date:July 2003
pp. 342
In this paper we explore the use of Priority-progress streaming (PPS) for video surveillance applications. PPS is an adaptive streaming technique for the delivery of continuous media over variable bit-rate channels. It is based on the simple idea of reorde...
 
Optimization of Adaptive Data-Flows for Competing Multimedia Presentational Database Sessions
Found in: Multimedia Computing and Systems, International Conference on
By Heiko Thimm, Wolfgang Klas, Crispin Cowan, Jonathan Walpole, Calton Pu
Issue Date:June 1997
pp. 328
Multimedia database systems must accommodate the capability to adapt the resource demand of executing presentations. This concerns adaptations across components of presentations as well as across concurrent sessions adhering to the individual needs of cont...
 
A case for relativistic programming
Found in: Proceedings of the 2012 ACM workshop on Relaxing synchronization for multicore and manycore scalability (RACES '12)
By Jonathan Walpole, Philip W. Howard
Issue Date:October 2012
pp. 33-38
Programmers traditionally assume we live and program in a sequentially consistent world. Hardware developers have long since abandoned sequential consistency in order to develop higher performance computers. In this paper, we argue that the natural world m...
     
Low-latency adaptive streaming over tcp
Found in: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)
By Ashvin Goel, Charles Krasic, Jonathan Walpole
Issue Date:August 2008
pp. 1-20
Media streaming over TCP has become increasingly popular because TCP's congestion control provides remarkable stability to the Internet. Streaming over TCP requires adapting to bandwidth availability, but unforunately, TCP can introduce significant latency...
     
Why the grass may not be greener on the other side: a comparison of locking vs. transactional memory
Found in: Proceedings of the 4th workshop on Programming languages and operating systems (PLOS '07)
By Jonathan Walpole, Maged M. Michael, Paul E. McKenney
Issue Date:October 2007
pp. 1-1
The advent of multi-core and multi-threaded processor architectures highlights the need to address the well-known shortcomings of the ubiquitous lock-based synchronization mechanisms. The emerging transactional-memory synchronization mechanism is viewed as...
     
Quality-adaptive media streaming by priority drop
Found in: Proceedings of the 13th international workshop on Network and operating systems support for digital audio and video (NOSSDAV '03)
By Charles Krasic, Jonathan Walpole, Wu-chi Feng
Issue Date:June 2003
pp. 112-121
This paper presents a general design strategy for streaming media applications in best effort computing and networking environments. Our target application is video on demand using personal computers and the Internet. In this scenario, where resource reser...
     
Provisioning on-line games: a traffic analysis of a busy counter-strike server
Found in: Proceedings of the second ACM SIGCOMM Workshop on Internet measurment workshop (IMW '02)
By Francis Chang, Jonathan Walpole, Wu-chang Feng, Wu-chi Feng
Issue Date:November 2002
pp. 151-156
This paper describes the results of a 500 million packet trace of a popular on-line, multi-player, game server. The results show that the traffic behavior of this heavily loaded game server is highly predictable and can be attributed to the fact that curre...
     
Priority-progress streaming for quality-adaptive multimedia
Found in: Proceedings of the ninth ACM international conference on Multimedia (MULTIMEDIA '01)
By Charles Krasic, Jonathan Walpole
Issue Date:September 2001
pp. 463-464
The Internet's ubiquity amply motivates us to harness it for video distribution, however, its best-effort service model is in direct conflict with video's inherent timeliness requirements. Today, the Internet is unrivaled in its rich composition, consistin...
     
Research challenges in environmental observation and forecasting systems
Found in: Proceedings of the sixth annual international conference on Mobile computing and networking (MobiCom '00)
By Antonio Baptista, Calton Pu, David C. Steere, Dylan McNamee, Jonathan Walpole
Issue Date:August 2000
pp. 292-299
We describe Environmental Observation and Forecasting Systems (EOFS), a new class of large-scale distributed system designed to monitor, model, and forecast wide-area physical processes such as river systems. EOFS have strong social relevance in areas such...
     
Operating systems specialization (invited talk) (abstract only): experiences, opportunities and challenges
Found in: Proceedings of the 2000 ACM SIGPLAN workshop on Partial evaluation and semantics-based program manipulation (PEPM '00)
By Jonathan Walpole
Issue Date:January 2000
pp. 253-263
This talk will present a systems-centric view of the opportunities, effectiveness, and challenges of applying specialization techniques to operating systems. The first part of the talk will focus on our experiences using manual and then tool-assisted speci...
     
Middleware for distributed multimedia (panel): need a new direction?
Found in: Proceedings of the fifth ACM international conference on Multimedia (MULTIMEDIA '97)
By David Hutchison, Guru Parulkar, Jonathan Walpole, Lawrence A. Rowe, Raj Yavatkar
Issue Date:November 1997
pp. 347
This paper addresses the problem of how to automatically generate visual representations of recorded histories of distributed multimedia collaborations. The work reported here focuses mainly on what we consider to be an innovative approach to this problem,...
     
Dynamic network reconfiguration support for mobile computers
Found in: Proceedings of the third annual ACM/IEEE international conference on Mobile computing and networking (MobiCom '97)
By Jim Binkley, Jon Inouye, Jonathan Walpole
Issue Date:September 1997
pp. 13-22
Post-hoc worknotes is a concept demonstration, an envisionment showing how workgroup communication could be supported using a combination of existing technologies in the field of nontextual information management. We have identified a number of use-driven ...
     
Demonstrating the effect of software feedback on a distributed real-time MPEG video audio player
Found in: Proceedings of the third ACM international conference on Multimedia (MULTIMEDIA '95)
By Calton Pu, Crispin Cowan, Jonathan Walpole, Richard Staehli, Shanwei Cen
Issue Date:November 1995
pp. 239-240
This paper addresses the problem of how to automatically generate visual representations of recorded histories of distributed multimedia collaborations. The work reported here focuses mainly on what we consider to be an innovative approach to this problem,...
     
Adaptive load migration systems for PVM
Found in: Proceedings of the 1994 ACM/IEEE conference on Supercomputing (Supercomputing '94)
By Jeremy Casas, Jonathan Walpole, Ravi Konuru, Robert Prouty, Steve W. Otto
Issue Date:November 1994
pp. 390-399
Adaptive load distribution is necessary for parallel applications to co-exist effectively with other jobs in a network of shared, heterogeneous workstations. We present three methods that provide such support for PVM applications. Two of these methods, MPV...
     
Objects to the rescue!: or httpd: the next generation operating system
Found in: Proceedings of the 6th workshop on ACM SIGOPS European workshop: Matching operating systems to application needs (EW 6)
By Andrew P. Black, Jonathan Walpole
Issue Date:September 1994
pp. 100-104
This position paper suggests that object-oriented operating systems may provide the means to meet the ever-growing demands of applications. As an example of a successful OOOS, we cite the http daemon. To support the contention that httpd is in fact an oper...
     
Incremental partial evaluation: the key to high performance, modularity and portability in operating systems
Found in: Proceedings of the 1993 ACM SIGPLAN symposium on Partial evaluation and semantics-based program manipulation (PEPM '93)
By Calton Pu, Charles Consel, Jonathan Walpole
Issue Date:June 1993
pp. 44-46
In general, a partial evaluator needs to keep track of the tasks that have already been completed or initiated, so that it can recognize when to stop unfolding. In the MIX-style polyvariant specialization algorithm, this is accomplished by a global log. Th...
     
Specialization tools and techniques for systematic optimization of system software
Found in: ACM Transactions on Computer Systems (TOCS)
By Ashvin Goel, Calton Pu, Charles Consel, Charles Krasic, Crispin Cowan, Dylan McNamee, Gilles Muller, Jonathan Walpole, Perry Wagle, Renauld Marlet
Issue Date:February 1992
pp. 217-251
Specialization has been recognized as a powerful technique for optimizing operating systems. However, specialization has not been broadly applied beyond the research community because current techniques based on manual specialization, are time-consuming an...
     
Design issues in the Cosmos distributed operating system
Found in: Proceedings of the 1988 workshop on ACM SIGOPS European workshop: Autonomy or interdependence in distributed systems? (EW 3)
By Gordon S. Blair, Javad Malik, John R. Nicol, Jonathan Walpole
Issue Date:September 1988
pp. 1-4
A hypercube multiprocessor is a MIMD distributed memory parallel computer in which 2**d nodes are connected in a d-dimensional hypercube topology. In this topology a d-dimensional cube is constructed out of two (d-1)-dimensional subcubes by connecting corr...
     
Device and physical data independence for multimedia presentations
Found in: ACM Computing Surveys (CSUR)
By David Maier, Jonathan Walpole, Richard Staehli
Issue Date:March 1988
pp. 640-642
Two-dimensional image motion is the projection of the three-dimensional motion of objects, relative to a visual sensor, onto its image plane. Sequences of time-orderedimages allow the estimation of projected two-dimensional image motion as either instantan...
     
Adaptive methods for distributed video presentation
Found in: ACM Computing Surveys (CSUR)
By Calton Pu, Crispin Cowan, Jonathan Walpole, Shanwei Cen
Issue Date:March 1988
pp. 580-583
Two-dimensional image motion is the projection of the three-dimensional motion of objects, relative to a visual sensor, onto its image plane. Sequences of time-orderedimages allow the estimation of projected two-dimensional image motion as either instantan...
     
 1