bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploiting Resonant Behavior to Reduce Inductive Noise
Authors: Powell Michael D. , Vijaykumar T. N.
Published: January 2005

Inductive noise in high-performance microprocessors is a reliabilityissue caused by variations in processor current (di/dt)which are converted to supply-voltage glitches by impedances inthe power-supply network. Inductive noise has been addressed byusing decoupling capacitors to maintain low impedance in thepower supply over a wide range of frequencies. However, evenwell-designed power supplies exhibit (a few) peaks of high impedanceat resonant frequencies caused by RLC resonant loops. Previousarchitectural proposals adjust current variations bycontrolling instruction fetch and issue, trading off performanceand energy for noise reduction. However, the proposals do notconsider some conceptual issues and have implementation challenges.The issues include requiring fast response, responding tovariations that do not threaten the noise margins, or respondingto variations only at the resonant frequency while the range ofhigh impedance extends to a resonance band around the resonantfrequency. While previous schemes reduce the magnitude of variations,our proposal, called resonance tuning, changes the frequencyof current variations away from the resonance band to anon-resonant frequency to be absorbed by the power supply.Because inductive noise is a resonance problem, resonance tuningreacts only to repeated variations in the resonance band, andnot to isolated variations. Reacting after a few repetitions allowsmore time for the response and reduces unnecessary responses,decreasing performance and energy loss.
The Vector-Thread Architecture
Authors: Krashinsky Ronny , Batten Christopher , Hampton Mark , Gerding Steve , Pharris Brian , Casper Jared , Asanovic Krste
Published: January 2005

The vector-thread (VT) architectural paradigm unifies the vectorand multithreaded compute models. The VT abstraction providesthe programmer with a control processor and a vector of virtualprocessors (VPs). The control processor can use vector-fetch commandsto broadcast instructions to all the VPs or each VP can usethread-fetches to direct its own control flow. A seamless intermixingof the vector and threaded control mechanisms allows a VT architectureto flexibly and compactly encode application parallelismand locality, and a VT machine exploits these to improve performanceand efficiency. We present SCALE, an instantiation of theVT architecture designed for low-power and high-performance embeddedsystems. We evaluate the SCALE prototype design usingdetailed simulation of a broad range of embedded applications andshow that its performance is competitive with larger and more complexprocessors.
Vote Early, Vote Often
Authors: Kelly-Bootle Stan
Published: January 2005

I usually shun clichés like the plague, but could not resist this oft-quoted slogan that sums up what I like to call Psephological Cynicism. Psephology is the huge and growing branch of mathematics (with frequent distractions from sociologists, psychologists, political scientists, and allied layabouts) that studies the structure and effectiveness of polling and electoral strategies. Related domains include probability and games theory, although, as well see, the subject has many far-from-playful implications. Indeed, there are depressing but valid proofs that no voting system fully guarantees “fair play.” Such non-existence theorems are common in most fields of mathematics: Gödel’s on the consistency proofs for certain arithmetical axioms, and Turing’s Halting Problem.
The blind men and the elephant
Authors: Go Kentaro , Carroll John M.
Published: January 2005

Six blind men encounter an elephant. Each of them touches a different part of the elephant and expresses what the elephant is. Although they are touching the same elephant, each man's description is completely different from that of the others. We have been using this story as a metaphor for understanding different views of scenario-based system design.
The race of the web sites
Authors: Gill Kathy E.
Published: January 2005

Four years ago the usability nod, like the popular vote, went to Democratic candidate Al Gore, and the review revealed common flaws as well as notable differences. In the intervening four years, surveys from organizations like the Pew Research Center show that more Americans are on line, and Democratic presidential candidate Howard Dean legitimized the Internet as a medium for political activism and fundraising. So how well are today's candidates communicating with this medium?
CSCW 2004
Authors: Campbell Marisa E.
Published: January 2005

CSCW 2004

November 6-10, 2004

Chicago, USA
Adopting ontology to facilitate knowledge sharing
Authors: Edgington Theresa , Choi Beomjin , Henson Katherine , Raghu T.S. , Vinze Ajay
Published: January 2005

Ontology-enabled knowledge management experiences derived from a domain ontology development project at Intel Corporation are described and assessed.
PetaFLOPS computing
Authors: Ebisuzaki Toshikazu , Germain Robert , Taiji Makoto
Published: January 2005

PetaFLOPS computers---capable of performing a thousand trillion mathematical operations per second, 25 times faster than the largest supercomputers today---will open new doors to understanding the functions of biological molecules.
The feasibility of supporting large-scale live streaming applications with dynamic application end-points
Authors: Sripanidkulchai Kunwadee , Ganjam Aditya , Maggs Bruce , Zhang Hui
Published: January 2005

While application end-point architectures have proven to be viable solutions for large-scale distributed applications such as distributed computing and file-sharing, there is little known about its feasibility for more bandwidth-demanding applications such as live streaming. Heterogeneity in bandwidth resources and dynamic group membership, inherent properties of application end-points, may adversely affect the construction of a usable and efficient overlay. At large scales, the problems become even more challenging. In this paper, we study one of the most prominent architectural issues in overlay multicast: the feasibility of supporting large-scale groups using an application end-point architecture. We look at three key requirements for feasibility: (i) are there enough resources to construct an overlay, (ii) can a stable and connected overlay be maintained in the presence of group dynamics, and (iii) can an efficient overlay be constructed? Using traces from a large content delivery network, we characterize the behavior of users watching live audio and video streams. We show that in many common real-world scenarios, all three requirements are satisfied. In addition, we evaluate the performance of several design alternatives and show that simple algorithms have the potential to meet these requirements in practice. Overall, our results argue for the feasibility of supporting large-scale live streaming using an application end-point architecture.
Turning the postal system into a generic digital communication mechanism
Authors: Wang Randolph Y. , Sobti Sumeet , Garg Nitin , Ziskind Elisha , Lai Junwen , Krishnamurthy Arvind
Published: January 2005

The phenomenon that rural residents and people with low incomes lag behind in Internet access is known as the "digital divide." This problem is particularly acute in developing countries, where most of the world's population lives. Bridging this digital divide, especially by attempting to increase the accessibility of broadband connectivity, can be challenging. The improvement of wide-area connectivity is constrained by factors such as how quickly we can dig ditches to bury fibers in the ground; and the cost of furnishing "last-mile" wiring can be prohibitively high.In this paper, we explore the use of digital storage media transported by the postal system as a general digital communication mechanism. While some companies have used the postal system to deliver software and movies, none of them has turned the postal system into a truly generic digital communication medium supporting a wide variety of applications. We call such a generic system a
Postmanet
. Compared to traditional wide-area connectivity options, the Postmanet has several important advantages, including wide global reach, great bandwidth potential and low cost.Manually preparing mobile storage devices for shipment may appear deceptively simple, but with many applications, communicating parties and messages, manual management becomes infeasible, and systems support at several levels becomes necessary. We explore the simultaneous exploitation of the Internet and the Postmanet, so we can combine their latency and bandwidth advantages to enable sophisticated bandwidth-intensive applications.
The design and implementation of a next generation name service for the internet
Authors: Ramasubramanian Venugopalan , Sirer Emin Gün
Published: January 2005

Name services are critical for mapping logical resource names to physical resources in large-scale distributed systems. The Domain Name System (DNS) used on the Internet, however, is slow, vulnerable to denial of service attacks, and does not support fast updates. These problems stem fundamentally from the structure of the legacy DNS.This paper describes the design and implementation of the Cooperative Domain Name System (CoDoNS), a novel name service, which provides high lookup performance through proactive caching, resilience to denial of service attacks through automatic load-balancing, and fast propagation of updates. CoDoNS derives its scalability, decentralization, self-organization, and failure resilience from peer-to-peer overlays, while it achieves high performance using the Beehive replication framework. Cryptographic delegation, instead of host-based physical delegation, limits potential malfeasance by namespace operators and creates a competitive market for namespace management. Backwards compatibility with existing protocols and wire formats enables CoDoNS to serve as a backup for legacy DNS, as well as a complete replacement. Performance measurements from a real-life deployment of the system in PlanetLab shows that CoDoNS provides fast lookups, automatically reconfigures around faults without manual involvement and thwarts distributed denial of service attacks by promptly redistributing load across nodes.
Mercury
Authors: Bharambe Ashwin R. , Agrawal Mukesh , Seshan Srinivasan
Published: January 2005

This paper presents the design of Mercury, a scalable protocol for supporting multi-attribute range-based searches. Mercury differs from previous range-based query systems in that it supports
multiple attributes
as well as performs
explicit load balancing
. To guarantee efficient routing and load balancing, Mercury uses novel light-weight sampling mechanisms for uniformly sampling random nodes in a highly dynamic overlay network. Our evaluation shows that Mercury is able to achieve its goals of logarithmic-hop routing and near-uniform load balancing.We also show that Mercury can be used to solve a key problem for an important class of distributed applications: distributed state maintenance for distributed games. We show that the Mercury-based solution is easy to use, and that it reduces the game's messaging overheard significantly compared to a naïve approach.
Collaborative recommendation
Authors: O'Mahony Michael , Hurley Neil , Kushmerick Nicholas , Silvestre Guénolé
Published: January 2005

Collaborative recommendation has emerged as an effective technique for personalized information access. However, there has been relatively little theoretical analysis of the conditions under which the technique is effective. To explore this issue, we analyse the robustness of collaborative recommendation: the ability to make recommendations despite (possibly intentional) noisy product ratings. There are two aspects to robustness: recommendation accuracy and stability. We formalize recommendation accuracy in machine learning terms and develop theoretically justified models of accuracy. In addition, we present a framework to examine recommendation stability in the context of a widely-used collaborative filtering algorithm. For each case, we evaluate our analysis using several real-world data-sets. Our investigation is both practically relevant for enterprises wondering whether collaborative recommendation leaves their marketing operations open to attack, and theoretically interesting for the light it sheds on a comprehensive theory of collaborative recommendation.
A review of vessel extraction techniques and algorithms
Authors: Kirbas Cemil , Quek Francis
Published: January 2005

Vessel segmentation algorithms are the critical components of circulatory blood vessel analysis systems. We present a survey of vessel extraction techniques and algorithms. We put the various vessel extraction approaches and techniques in perspective by means of a classification of the existing research. While we have mainly targeted the extraction of blood vessels, neurosvascular structure in particular, we have also reviewed some of the segmentation methods for the tubular objects that show similar characteristics to vessels. We have divided vessel segmentation algorithms and techniques into six main categories: (1) pattern recognition techniques, (2) model-based approaches, (3) tracking-based approaches, (4) artificial intelligence-based approaches, (5) neural network-based approaches, and (6) tube-like object detection approaches. Some of these categories are further divided into subcategories. We have also created tables to compare the papers in each category against such criteria as dimensionality, input type, preprocessing, user interaction, and result type.
Bioinformatics—an introduction for computer scientists
Authors: Cohen Jacques
Published: January 2005

The article aims to introduce computer scientists to the new field of bioinformatics. This area has arisen from the needs of biologists to utilize and help interpret the vast amounts of data that are constantly being gathered in genomic research---and its more recent counterparts, proteomics and functional genomics. The ultimate goal of bioinformatics is to develop in silico models that will complement in vitro and in vivo biological experiments. The article provides a bird's eye view of the basic concepts in molecular cell biology, outlines the nature of the existing data, and describes the kind of computer algorithms and techniques that are necessary to understand cell behavior. The underlying motivation for many of the bioinformatics approaches is the evolution of organisms and the complexity of working with incomplete and noisy data. The topics covered include: descriptions of the current software especially developed for biologists, computer and mathematical cell models, and areas of computer science that play an important role in bioinformatics.
Safe compositional specification of networking systems
Authors: Bestavros Azer , Bradley Adam , Kfoury Assaf , Matta Ibrahim
Published: January 2005

The science of network service composition has emerged as one of the grand themes of networking research [17] as a direct result of the complexity and sophistication of emerging networked systems and applications. By "service composition" we mean that the performance and correctness properties local to the various constituent components of a service can be readily composed into global (end-to-end) properties without re-analyzing any of the constituent components in isolation, or as part of the whole composite service. The set of laws that govern such composition is what will constitute that new science of composition.

The heterogeneity and open nature of network systems make composition quite challenging, and thus programming network services has been largely inaccessible to the average user. We identify (and outline) a research agenda in which we aim to develop a specification language that is expressive enough to describe different components of a network service, and that will include type hierarchies inspired by type systems in general programming languages that enable the safe composition of software components. We envision this new science of composition to be built upon several theories, possibly including control theory, network calculus, scheduling theory, and game theory. In essence, different theories may provide different languages by which certain properties of system components can be expressed and composed into larger systems. We then seek to lift these lower-level specifications to a higher level by abstracting away details that are irrelevant for safe composition at the higher level, thus making theories scalable and useful to the average user. In this paper we focus on services built upon an overlay traffic management architecture, and we use control theory and QoS theory as example theories from which we lift up compositional specifications.
Consistency models for distributed interactive multimedia applications
Authors: Bouillot Nicolas , Gressier-Soudan Eric
Published: January 2005

Distributed Interactive Multimedia Applications (DIMA) are "human in the loop" applications. Their aim is to support real-world like interactions through a virtual world in a broader sense. However, propagation delays, jitter and losses due to network communications naturally lead to inconsistencies, when local and remote actions performed by users/clients are played out. This constraint makes the management of replicated multimedia shared data a real challenge. In the literature, various consistency models are proposed and each of them brings their own complexity and distortion among interactions. In this paper, we provide hints to help DIMA designers to choose appropriate consistency models by first presenting meaningful psycho-perceptive characteristics of the real-world interactions and then discussing various consistency models according to them.
Introduction
Authors: Rosenbloom Andrew
Published: January 2005

Weblogs are a relatively new form of mainstream personal communication, like instant messaging, email, cell phones, and Web pages. They're also a new voice for traditional mass-market newspapers, magazines, and broadcasters.
Using confidence scores to improve hands-free speech based navigation in continuous dictation systems
Authors: Feng Jinjuan , Sears Andrew
Published: January 2005

Speech recognition systems have improved dramatically, but recent studies confirm that error correction activities still account for 66--75% of the users' time, and 50% of that time is spent just getting to the errors that need to be corrected. While researchers have suggested that confidence scores could prove useful during the error correction process, the focus is typically on error detection. More importantly, empirical studies have failed to confirm any measurable benefits when confidence scores are used in this way within dictation-oriented applications. In this article, we provide data that explains why confidence scores are unlikely to be useful for error detection. We propose a new navigation technique for use when speech-only interactions are strongly preferred and common, desktop-sized displays are available. The results of an empirical study that highlights the potential of this new technique are reported. An informal comparison between the current study and previous research suggests the new technique reduces time spent on navigation by 18%. Future research should include additional studies that compare the proposed technique to previous non-speech and speech-based navigation solutions.
Differences in pointing task performance between preschool children and adults using mice
Authors: Hourcade Juan Pablo , Bederson Benjamin B. , Druin Allison , Guimbretière François
Published: January 2005

Several experiments by psychologists and human factors researchers have shown that when young children execute pointing tasks, they perform at levels below older children and adults. However, these experiments have not provided user interface designers with an understanding of the severity or the nature of the difficulties young children have when using input devices. To address this need, we conducted a study to gain a better understanding of 4 and 5 year-old children's use of mice. We compared the performance of thirteen 4 year-olds, thirteen 5 year-olds and thirteen young adults in point-and-click tasks. Plots of the paths taken by the participants show severe differences between adults' and preschool children's ability to control the mouse. We were not surprised then to find age had a significant effect on accuracy, target reentry, and efficiency. We also found that target size had a significant effect on accuracy and target reentry. Measuring movement time at four different times (first entering target, last entering target, pressing button, releasing button) yielded the result that Fitts' law models children well only up to the time they first enter the target. Overall, we found that the difference between the performance of children and adults was large enough to warrant user interface interactions designed specifically for preschool children. The results additionally suggest that children need the most help once they get close to targets.
A study of web usability for older adults seeking online health resources
Authors: Becker Shirley Ann
Published: January 2005

The Web offers older adult users immediate access to health resources that might not otherwise be available. Older adult users, however, may encounter Web barriers associated with normal aging and lower education. The National Institute on Aging Web guidelines were used to assess the usability of 125 Web sites offering health resources. Performance, translation, and reading complexity were also assessed. Results showed that many of the sampled sites were not senior-friendly. Only 12% of the sites offered a Spanish version, many containing nontranslated text. Approximately a third of sampled sites required a college education to comprehend extracted health information.
Letters
Authors: Grossman Edward
Published: January 2005

Being German, I love the unsurpassed combinatorial possibilities of our language. Stan Kelly-Bootle’s “From this Moment On” (June 2004), however, contains a construction, “Entunternehhmangenausstreckenisierung,” that defies my linguistic capabilities. Ent... what?
Review of “Immunity-based systems by Yoshiteru Ishida”. Springer-Verlag, 2004, ISBN 3-540-00896-9.
Authors: Ayesh Alladin
Published: January 2005

Review of “Immunity-based systems by Yoshiteru Ishida”. Springer-Verlag, 2004, ISBN 3-540-00896-9.
An improvement of security enhancement for the timestamp-based password authentication scheme using smart cards
Authors: yang Chou-Chen , Wang Ren-Ching
Published: January 2005

Recently, Yang and Shieh proposed a timestamp-based and a nonce-based password authentication schemes. In 2002, Chan and Cheng pointed out that Yang and Shieh's timestamp-based password authentication scheme was vulnerable to the forgery attack. However, in 2003, Sun and Yeh pointed out that Chan and Cheng's attack was unreasonable. At the same time, Sun and Yeh pointed out that Yang and Shieh's password authentication schemes were still vulnerable to the forgery attack. Later Shen et al. proposed a modified scheme to resist Chan and Cheng's attack. In this paper, we shall point out that Shen et al.'s improvement is vulnerable to the forgery attack and find their scheme still cannot resist Sun and Yeh's attack. At the same time, we shall propose a solution to resist the above attacks.
What’s on Your Hard Drive?
Authors: Grossman Edward
Published: January 2005

Clean, fast, multi-platform, and somewhat terse, it writes client and server code anywhere. It’s powerful enough to not get in the way of expressing complex designs... and rapidly scrapping them.
Scenario-based comparison of source-tracing and dynamic source routing protocols for ad hoc networks
Authors: Raju Jyoti , Garcia-Luna-Aceves J. J.
Published: January 2005

We present source tracing as a new viable approach to routing in ad hoc networks in which routers communicate the second-to-last hop and distance in preferred paths to destinations. We introduce a table-driven protocol (BEST) in which routers maintain routing information for all destinations, and an on-demand routing protocol (DST) in which routers maintain routing information for only those destinations to whom they need to forward data. Simulation experiments are used to compare these protocols with DSR, which has been shown to incur less control overhead that other on-demand routing protocols. The simulations show that DST requires far less control packets to achieve comparable or better average delays and percentage of packet delivered than DSR, and that BEST achieves comparable results to DSR while maintaining routing information for all destinations.
Network security, off the racks
Authors: Weiss Aaron
Published: January 2005

Quite a few years ago I wrote a book about protecting yourself on the Internet. The book was aimed at the first wave of mainstream users to hit the global network, as traffic spread beyond the scientific and academic communities. In it, I argued a "reasonable precautions" thesis of home---in essence, the Internet was like a house, and so long as you locked your windows and doors, you'd probably be fine. There was a lot of hyped paranoia at the time, much of it sensational. Stronger defenses, I felt, were only necessary if you had reason to become a target, because of who you were, where you were, or what you had.
Coherence decoupling
Authors: Huh Jaehyuk , Chang Jichuan , Burger Doug , Sohi Gurindar S.
Published: January 2005

This paper explores a new technique called
coherence decoupling
, which breaks a traditional cache coherence protocol into two protocols: a Speculative Cache Lookup (SCL) protocol and a safe, backing coherence protocol. The SCL protocol produces a speculative load value, typically from an invalid cache line, permitting the processor to compute with incoherent data. In parallel, the coherence protocol obtains the necessary coherence permissions and the correct value. Eventually, the speculative use of the incoherent data can be verified against the coherent data. Thus, coherence decoupling can greatly reduce --- if not eliminate --- the effects of false sharing. Furthermore, coherence decoupling can also reduce latencies incurred by true sharing. SCL protocols reduce those latencies by speculatively writing updates into invalid lines, thereby increasing the accuracy of speculation, without complicating the simple, underlying coherence protocol that guarantees correctness.The performance benefits of coherence decoupling are evaluated using a full-system simulator and a mix of commercial and scientific benchmarks. Our results show that 40% to 90% of all coherence misses can be speculated correctly, and therefore their latencies partially or fully hidden. This capability results in performance improvements ranging from 3% to over 16%, in most cases where the latencies of coherence misses have an effect on performance.
Devirtualizable virtual machines enabling general, single-node, online maintenance
Authors: Lowell David E. , Saito Yasushi , Samberg Eileen J.
Published: January 2005

Maintenance is the dominant source of downtime at high availability sites. Unfortunately, the dominant mechanism for reducing this downtime, cluster rolling upgrade, has two shortcomings that have prevented its broad acceptance. First, cluster-style maintenance over many nodes is typically performed a few nodes at a time, mak-ing maintenance slow and often impractical. Second, cluster-style maintenance does not work on single-node systems, despite the fact that their unavailability during maintenance can be painful for organizations. In this paper, we propose a novel technique for online maintenance that uses virtual machines to provide maintenance on single nodes, allowing parallel maintenance over multiple nodes, and online maintenance for standalone servers. We present the Microvisor, our prototype virtual machine system that is custom tailored to the needs of online maintenance. Unlike general purpose virtual machine environments that induce continual 10-20% over-head, the Microvisor virtualizes the hardware only during periods of active maintenance, letting the guest OS run at full speed most of the time. Unlike past attempts at virtual machine optimization, we do not compromise OS transparency. We instead give up generality and tailor our virtual machine system to the minimum needs of online maintenance, eschewing features, such as I/O and memory virtualization, that it does not strictly require. The result is a very thin virtual machine system that induces only 5.6% CPU overhead when virtualizing the hardware, and zero CPU overhead when
devirtualized
. Using the Microvisor, we demonstrate an online OS upgrade on a live, single-node web server, reducing downtime from one hour to less than one minute.
Performance directed energy management for main memory and disks
Authors: Li Xiaodong , Li Zhenmin , David Francis , Zhou Pin , Zhou Yuanyuan , Adve Sarita , Kumar Sanjeev
Published: January 2005

Much research has been conducted on energy management for memory and disks. Most studies use control algorithms that dynamically transition devices to low power modes after they are idle for a certain threshold period of time. The control algorithms used in the past have two major limitations. First, they require painstaking, application-dependent manual tuning of their thresholds to achieve energy savings without significantly degrading performance. Second, they do not provide performance guarantees. In one case, they slowed down an application by 835.This paper addresses these two limitations for both memory and disks, making memory/disk energy-saving schemes practical enough to use in real systems. Specifically, we make three contributions: (1) We propose a technique that provides a performance guarantee for control algorithms. We show that our method works well for all tested cases, even with previously proposed algorithms that are not performance-aware. (2) We propose a new control algorithm,
Performance-directed Dynamic
(PD), that dynamically adjusts its thresholds periodically, based on available slack and recent workload characteristics. For memory, PD consumes the least energy, when compared to previous hand-tuned algorithms combined with a performance guarantee. However, for disks, PD is too complex and its self-tuning is unable to beat previous hand-tuned algorithms. (3) To improve on PD, we propose a simple, optimization-based, threshold-free control algorithm,
Performance-directed Static
(PS). PS periodically assigns a static configuration by solving an optimization problem that incorporates information about the available slack and recent traffic variability to different chips/disks. We find that PS is the best or close to the best across all performanceguaranteed disk algorithms, including hand-tuned versions.
D-SPTF
Authors: Lumb Christopher R. , Golding Richard
Published: January 2005

Distributed Shortest-Positioning Time First (D-SPTF) is a request distribution protocol for decentralized systems of storage servers. D-SPTF exploits high-speed interconnects to dynamically select which server, among those with a replica, should service each read request. In doing so, it simultaneously balances load, exploits the aggregate cache capacity, and reduces positioning times for cache misses. For network latencies expected in storage clusters (e.g., 10--200μs), D-SPTF performs as well as would a hypothetical centralized system with the same collection of CPU, cache, and disk resources. Compared to popular decentralized approaches, D-SPTF achieves up to 65% higher throughput and adapts more cleanly to heterogenous server capabilities.
FAB
Authors: Saito Yasushi , Frølund Svend , Veitch Alistair , Merchant Arif , Spence Susan
Published: January 2005

This paper describes the design, implementation, and evaluation of a Federated Array of Bricks (FAB), a distributed disk array that provides the reliability of traditional enterprise arrays with lower cost and better scalability. FAB is built from a collection of
bricks
, small storage appliances containing commodity disks, CPU, NVRAM, and network interface cards. FAB deploys a new majority-voting-based algorithm to replicate or erasure-code logical blocks across bricks and a reconfiguration algorithm to move data in the background when bricks are added or decommissioned. We argue that voting is practical and necessary for reliable, high-throughput storage systems such as FAB. We have implemented a FAB prototype on a 22-node Linux cluster. This prototype sustains 85MB/second of throughput for a database workload, and 270MB/second for a bulk-read workload. In addition, it can outperform traditional master-slave replication through performance decoupling and can handle brick failures and recoveries smoothly without disturbing client requests.
Low-overhead memory leak detection using adaptive statistical profiling
Authors: Hauswirth Matthias , Chilimbi Trishul M.
Published: January 2005

Sampling has been successfully used to identify performance optimization opportunities. We would like to apply similar techniques to check program correctness. Unfortunately, sampling provides poor coverage of infrequently executed code, where bugs often lurk. We describe an adaptive profiling scheme that addresses this by sampling executions of code segments at a rate inversely proportional to their execution frequency. To validate our ideas, we have implemented SWAT, a novel memory leak detection tool. SWAT traces program allocations/ frees to construct a heap model and uses our adaptive profiling infrastructure to monitor loads/stores to these objects with low overhead. SWAT reports 'stale' objects that have not been accessed for a 'long' time as leaks. This allows it to find all leaks that manifest during the current program execution. Since SWAT has low runtime overhead (‹5%), and low space overhead (‹10% in most cases and often less than 5%), it can be used to track leaks in production code that take days to manifest. In addition to identifying the allocations that leak memory, SWAT exposes where the program last accessed the leaked data, which facilitates debugging and fixing the leak. SWAT has been used by several product groups at Microsoft for the past 18 months and has proved effective at detecting leaks with a low false positive rate (‹10%).
Application-level checkpointing for shared memory programs
Authors: Bronevetsky Greg , Marques Daniel , Pingali Keshav , Szwed Peter , Schulz Martin
Published: January 2005

Trends in high-performance computing are making it necessary for long-running applications to tolerate hardware faults. The most commonly used approach is checkpoint and restart (CPR) - the state of the computation is saved periodically on disk, and when a failure occurs, the computation is restarted from the last saved state. At present, it is the responsibility of the programmer to instrument applications for CPR.Our group is investigating the use of compiler technology to instrument codes to make them self-checkpointing and self-restarting, thereby providing an automatic solution to the problem of making long-running scientific applications resilient to hardware faults. Our previous work focused on message-passing programs.In this paper, we describe such a system for shared-memory programs running on symmetric multiprocessors. This system has two components: (i) a pre-compiler for source-to-source modification of applications, and (ii) a runtime system that implements a protocol for coordinating CPR among the threads of the parallel application. For the sake of concreteness, we focus on a non-trivial subset of OpenMP that includes barriers and locks.One of the advantages of this approach is that the ability to tolerate faults becomes embedded within the application itself, so applications become self-checkpointing and self-restarting on any platform. We demonstrate this by showing that our transformed benchmarks can checkpoint and restart on three different platforms (Windows/x86, Linux/x86, and Tru64/Alpha). Our experiments show that the overhead introduced by this approach is usually quite small; they also suggest ways in which the current implementation can be tuned to reduced overheads further.
Adaptation of performed ballistic motion
Authors: Sulejmanpašić Adnan , Popović Jovan
Published: January 2005

Adaptation of ballistic motion demands a technique that can make required adjustments in anticipation of flight periods when only some physically consistent changes are possible. This article describes a numerical procedure that adjusts a physically consistent motion to fulfill new adaptation requirements expressed in kinematic and dynamic constraints. This iterative procedure refines the original motion with a sequence of minimal adjustments, implicitly favoring motions that are similar to the original performance, and transforming any input motion, including those that are difficult to characterize with an objective function. In total, over twenty adaptations were generated from two recorded performances, a run and a jump, by varying foot placement, restricting muscle use, adding new environment constraints, and changing the length and mass of specific limbs.
QoS-aware multicasting in DiffServ domains
Authors: Li Zhi , Mohapatra Prasant
Published: January 2005

QoS-aware multicasting is becoming more and more desirable with the expanding usage of group-based applications, especially those involving multimedia objects. Until now, most of the proposed QoS-aware multicasting routing protocols adopt per-flow based resource reservation. Although these schemes can be adopted in integrated services (IntServ) Internet, they are not suitable for more scalable Differentiated Services (DiffServ) Internet. A new QoS-aware multicast routing protocol called QMD is proposed for DiffServ environments in this paper. Based on the design philosophy of DiffServ, the complex multicasting control plane functionalities are removed from the core routers. In addition, for each multicast group, only a limited set of on-tree routers (termed as key nodes) maintain multicast routing states and forward multicast data traffic. The key nodes of a multicast group uniquely identify a QoS-satisfied multicast tree connecting the group members. Although the other on-tree routers between any two key nodes do not maintain any multicast routing states and QoS reservation information, the group members' QoS requirements can still be satisfied. Through simulation experiments based on both random and real intra-domain topologies, we have also demonstrated that QMD can provide higher QoS-satisfaction rate while maintaining the simplicity of core routers.
New techniques for making transport protocols robust to corruption-based loss
Authors: Eddy Wesley M. , Ostermann Shawn , Allman Mark
Published: January 2005

Current congestion control algorithms treat packet loss as an indication of network congestion, under the assumption that most losses are caused by router queues overflowing. In response to losses (congestion), a sender reduces its sending rate in an effort to reduce contention for shared network resources. In network paths where a non-negligible portion of loss is caused by packet corruption, performance can suffer due to needless reductions of the sending rate (in response to "perceived congestion" that is not really happening). This paper explores a technique, called Cumulative Explicit Transport Error Notification (CETEN), that uses information provided by the network to bring the transport's long-term average sending rate closer to that dictated by only congestion-based losses. We discuss several ways that information about the cumulative rates of packet loss due to congestion and corruption might be obtained from the network or through fairly generic transport layer instrumentation. We then explore two ways to use this information to develop a more appropriate congestion control response (CETEN). The work in this paper is done in terms of TCP. Since numerous transport protocols use TCP-like congestion control schemes, the CETEN techniques we present are applicable to other transports as well. In this paper, we present early simulation results that show CETEN to be a promising technique. In addition, this paper discusses a number of practical and thorny implementation issues associated with CETEN.
WICSA Wiki WAN Party
Authors: Cheng Shang-Wen , Nord Robert L. , Stafford Judith A.
Published: January 2005

Researchers, practitioners, educators, and students of software architecture would benefit from having online access to quality information about the state of research and practice of software architecture. In recent years, Wiki technology has enabled distributed and collaborative editing of content using only a Web browser. To explore whether Wiki technology would be effective in facilitating the ongoing discussion and evolution of ideas on software architecture, we hosted the WICSA Wiki WAN Party (WWWP) during the 4th Working IEEE/IFIP Conference on Software Architecture (WICSA 2004). We used a history tool developed at IBM Research to monitor site activity and provide daily feedback to conference participants. This report recounts experience hosting this Wiki site and summarizes the site activity.
A summary of the ICSE 2004 workshop on "scenarios and state machines
Authors: Giese Holger , Krüger Ingolf
Published: January 2005

This summary reports on the third workshop in the SCESM (SCEnarios and State Machines) series held at the International Conference on Software Engineering (ICSE) in 2004 in Edinburgh, Scotland. SCESM'04 continues the very successful preceding workshops on this topic, which include a workshop on scenariobased round-trip engineering at OOPSLA 2000, two SCESM workshops at ICSE 2002 [1] and ICSE 2003 [2], and a Dagstuhl Seminar in September 2003 [3]. SCESM'04 has followed this tradition and brought together researchers and practitioners interested in advancing models, algorithms and tools for scenario- and state-oriented approaches to software and systems engineering.
Software safety
Authors: Bhansali P. V.
Published: January 2005

This paper describes the current status of software safety in terms of research and existing standards. It highlights the differences between various standards set up by government agencies to accomplish the same safety objectives. For example, European standards tend to place more emphasis on static analysis whereas American standards prefer dynamic testing to verify the software. An optimal verification approach is still a debatable issue in the software safety community. As for future direction, the author believes that the key to making safer and cheaper software is to have better requirements validation that ensure that the requirements are correct and complete before the design and coding phases begin.
Software agents using simulation for decision-making
Authors: Kuehne Ralph , Wille Cornelius , Dumke Reiner
Published: January 2005

Though autonomy is one of the major concepts of agent technology, the question how to implement this autonomy is mainly up to the agent developer. To show autonomous behaviour the agent has to make decisions regarding which actions to take next in order to meet its design objectives. This article suggests the use of simulation by an agent in its decision-making process. While simulation-based planning has already been proposed, we take it one step further and also use it for the control of the system the agent is reasoning about and for enabling the agent to take measures proactively. To explore this idea's potential we have implemented an agent test-bed to experimentally compare simulation-based decision-making with a rule-based implementation in a manufacturing control scenario. Both the implementation and the simulation study are presented in this article. Based on how the corresponding agents performed in reducing the production cycle time and in reasoning about the probability of meeting the delivery due date, we conclude that the use of simulation for such planning and control purposes is a promising, intuitive and competitive approach that is well suited to supplement other approaches that are already in use.
Towards a rule model for self-adaptive software
Authors: Wang Qianxiang
Published: January 2005

Most self-adaptive software use rules explicitly or implicitly to decide how to react to monitored events. Meanwhile, rules are usually scattered in different procedures, which makes procedures more complex. This paper proposes a Rule Model, which is used to extract scattered rules from different procedures, so as to enhance the self-adaptive ability of software. The paper presents what is Rule Model, including: three key concepts (event, parameter, and rule), hierarchical organization, role in application, and XML-based representation. The paper also introduces how to map declarative rules inside one deployable application to executable rules inside one rule engine, based on one J2EE-compliant application server.
New lattice-based cryptographic constructions
Authors: Regev Oded
Published: January 2005

We introduce the use of Fourier analysis on lattices as an integral part of a lattice-based construction. The tools we develop provide an elegant description of certain Gaussian distributions around lattice points. Our results include two cryptographic constructions that are based on the worst-case hardness of the unique shortest vector problem. The main result is a new public key cryptosystem whose security guarantee is considerably stronger than previous results (
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)). This provides the first alternative to Ajtai and Dwork's original 1996 cryptosystem. Our second result is a family of collision resistant hash functions with an improved security guarantee in terms of the unique shortest vector problem. Surprisingly, both results are derived from one theorem that presents two indistinguishable distributions on the segment [0, 1). It seems that this theorem can have further applications; as an example, we use it to solve an open problem in quantum computation related to the dihedral hidden subgroup problem.
Review: Spoken Dialogue Technology
Authors: Portele T.
Published: January 2005

Review: Spoken Dialogue Technology
Extensible Programming for the 21st Century
Authors: Wilson Gregory V.
Published: January 2005

In his keynote address at OOPSLA ’98, Sun Microsystems Fellow Guy L. Steele Jr. said, “From now on, a main goal in designing a language should be to plan for growth.” Functions, user-defined types, operator overloading, and generics (such as C++ templates) are no longer enough: tomorrow’s languages must allow programmers to add entirely new kinds of information to programs, and control how it is processed. This article argues that next-generation programming systems can accomplish this by combining three specific technologies.
Locality in a web of streams
Authors: Fonseca Rodrigo , Almeida Virgílio , Crovella Mark
Published: January 2005

Identifying a framework for addressing the challenges inherent in the complexity of contemporary Web architecture.
A framework for evaluating third-party logistics
Authors: Vaidyanathan Ganesh
Published: January 2005

3PL providers with advanced IT are expected to lower logistics costs and integrate the supply chain with increased productivity and growth. Here, a set of criteria for choosing the most suitable provider.
Using the DEA methodology to rank software technical efficiency
Authors: Herrero Ines , Salmeron Jose L.
Published: January 2005

The use of Data Envelopment Analysis to evaluate software efficiency offers a more formal and effective option.
The unconscious art of software testing
Authors: Armour Phillip G.
Published: January 2005

The subtle psychology of testing.
The challenges of IDC
Authors: Kestenbaum David
Published: January 2005

A conversation with Seymour Papert, Marvin Minsky, and Alan Kay.
Children's intuitive gestures in vision-based action games
Authors: Höysniemi Johanna , Hämäläinen Perttu , Turkki Laura , Rouvi Teppo
Published: January 2005

Novel computer vision-based game technologies aim to give players more immersive and physically challenging gaming experiences.
The material side of educational technology
Authors: Eisenberg Michael
Published: January 2005

Materials science presents an amazing array of unique substances offering a rich, and challenging, dimension to future educational tools and technologies.