bluuebunny/crossref_metadata_2025 huggingface dataset:
Experience with "link-up notification" over a mobile satellite link
Authors: Duke Martin , Henderson Thomas R. , Meegan Jeff
Published: January 2005

Over paths characterized by extended outage periods, a TCP connection can suffer a severe performance penalty due to its Retransmission Timeout (RTO) backoff mechanism. If outages are long enough, the RTO can grow large enough to cause unacceptably long pauses when the link is eventually restored. One proposed solution is "Link-Up Notification" (LUN), which involves an intermediate device that can detect the link state. When the link is restored, the device immediately sends a packet that causes traffic to resume, terminating the TCP timeout.

We have implemented a version of LUN that we call "kickstart." A kickstart gateway buffers a packet from each connection and uses them to restart the connections when the channel is restored. Based on empirical data, we have built a mobile satellite channel emulator and demonstrated how the technique can effectively eliminate the pause in restarting a TCP flow once a blocked channel is reestablished. When conducting experiments with shorter channel outages and shorter TCP flows, a different picture emerges; in this case, while connection transfer times are not noticeably reduced by a kickstart gateway, the overall completion ratio of TCP connections is increased, as fewer connections are dropped due to exceeding the maximum number of retransmissions. Our experiments also exposed some problems in the Linux and FreeBSD end host TCP implementations that impair performance in such an environment. Correcting these problems improves success ratios still more, while having little positive effect on transfer times.
A global stability result for primal-dual congestion control algorithms with routing
Authors: Voice Thomas
Published: January 2005

We prove a global stability result for a fluid approximation of a class of Internet-like communications networks operating a form of congestion control with routing. The network consists of an arbitrary interconnection of sources and links with negligible propagation delays. The model here allows for arbitrary strictly concave utility functions and the presence of dynamics at both sources and links.
Building the blocks of protocol design and analysis
Authors: Bai Fan , Bhaskara Ganesha , Helmy Ahmed
Published: January 2005

With the emergence of new application-specific sensor and Ad-hoc networks, increasingly complex and custom protocols will be designed and deployed. We propose a framework to systematically design and evaluate networking protocols based on a 'building block' approach. In this approach, each protocol is broken down into a set of parameterized modules called "building blocks", each having its own specific functionality. The properties of these building blocks and their interaction define the overall behavior of the protocol. In this paper, we aim to identify the major research challenges and questions in the building block approach. By addressing some of those questions, we point out potential directions to analyze and understand the behavior of networking protocols systematically. We discuss two case studies on utilizing the building block approach for analyzing Ad-hoc routing protocols and IP mobility protocols in a systematic manner.
An intrusion-tolerant authorization and authentication scheme in distributed environments
Authors: Yuan-bo Guo , Jian-feng Ma
Published: January 2005

In this paper, we introduce an intrusion-tolerant authorization and authentication scheme in distributed environments, by the utilization of a secure multi-party computation scheme by virtue of Feldman's (t + 1, n) VSS to perform the warrant authorization. In this way, a warrant can be obtained in a distributed fashion in which any k of registration severs are required to perform the computation. The n segments of the private key of the registration severs set---which are spread across n registration severs---do not have to be recombined on a single machine to perform a warrant authorization. Since k << n, the requirement that only k segments are needed inherently provides system reliability.
An improvement of delegated multisignature scheme with document decomposition
Authors: Chang Chin-Chen , Lin Iuon-Chang
Published: January 2005

Delegate multisignature scheme with document decomposition, introduced by Wu, Hung, and Guan, allow each signatory only signs a part of the document according to the signatory's knowledge domain. In some applications, it is indeed more efficient than the traditional multisignature schemes that each signatory must sign the whole document. However, there is a disadvantage of this scheme. An adversary can make the signature collector (SC) to verify individual signatures successfully, although the result in generating a multisugnature that cannot pass the multisignature verification. This is inefficient because SC cannot identify which partial signature is wrong. If the multisignature cannot pass the verification, then all participant signatories have to resend their partial signature. In this paper, we will show this disadvantage and then improve the Wu-Hung-Guan's delegated multisignature scheme to remedy this disadvantage.
A convertible group signature scheme
Authors: Chang Chin-Chen , Lai Yeu-Pong
Published: January 2005

The digital signature technique is a popular research branch in the field of contemporary cryptography because of its popularity in both economic and official applications. As more and more information gets processed digitally, digital signatures come to play a more and more important role. The prevention of the signature repudiation is therefore a basic requirement for digital signature techniques living up to. However, in some signature schemes, the validity of the signature is confirmed through some extra parameters or by certain trusted third parties. In 1999, Araki et al. proposed a scheme known for being convertible. In their scheme, certain verifiers can examine the signature without the help of the signers. Since then, many researchers have been devoted to the research and development of schemes with such a property. In this paper, we shall propose a new convertible group signature scheme. Our new scheme is based on two assumptions: the complexity of the discrete logarithm problem and the un-reversibility of the one-way hash function. In our discussion section later, we shall consider some possible attacks and prove that our new scheme is able to survive them. In addition, the special strength of our scheme is its efficient verification mechanism.
Comments on multiparty key exchange scheme
Authors: Lee Narn-Yih , Lee Ming-Feng
Published: January 2005

Recently, Chang and Chan proposed a new key exchange scheme based on the hyperspherical equation. However, we find that the Chang-Chan multiparty key exchange scheme is vulnerable to the malicious participant attack and the modification attack. This paper will show the security flaws in the Chang-Chan scheme.
Remarks on fingerprint-based remote user authentication scheme using smart cards
Authors: Chang Chin-Chen , Lin Iuon-Chang
Published: January 2005

In 2002, Lee, Ryu, and Yoo proposed a fingerprint-based remote user authentication scheme using smart cards. The scheme makes it possible for authenticating the legitimacy of each login user without any password table. In addition, the authors claimed that the scheme can withstand message replay attack and impersonation. In this paper, we shall point out a security flaw in this scheme, that is, n legitimate users can conspire to forge 2n-n-1 valid IDs and PWs for successfully passing the system authentication. Furthermore, we also show that the authentication equation is incorrect. Thus, the scheme is unworkable.
Introduction to Stephe's Ada library
Authors: Leake Stephen
Published: January 2005

Stephe's Ada Library (SAL) containers are designed to support the widest possible range of item and container types (limited/non-limited, indefinite/definite, etc). SAL containers are defined by the operations required to implement algorithms. Issues that arise in the implementation of this design are discussed.
A fast, memory-efficient register allocation framework for embedded systems
Authors: Thammanur Sathyanarayanan , Pande Santosh
Published: January 2005

In this work, we describe a "just-in-time," usage density-based register allocator geared toward embedded systems with a limited general-purpose register set wherein speed, code size, and memory requirements are of equal concern. The main attraction of the allocator is that it does not make use of the traditional live range and interval analysis nor does it perform advanced optimizations based on range splitting but results in very good code quality. We circumvent the need for traditional analysis by using a measure of usage density of a variable. The usage density of a variable at a program point represents both the frequency and the density of the uses. We contend that by using this measure we can capture both range and frequency information which is essentially used by the good allocators based on splitting. We describe a framework based on this measure which has a linear complexity in terms of the program size. We perform comparisons with the static allocators based on graph coloring and the ones targeted toward just-in-time compilation systems like linear scan of live ranges. Through comparisons with graph coloring (Brigg's style) and live range-based (linear scan) allocators, we show that the memory footprint and the size of our allocator are smaller by 20% to 30%. The speed of allocation is comparable and the speed of the generated code is better and its size smaller. These attributes make the allocator an attractive candidate for performing a fast, memory-efficient register allocation for embedded devices with a small number of registers.
Automatic tiling of iterative stencil loops
Authors: Li Zhiyuan , Song Yonghong
Published: January 2005

Iterative stencil loops are used in scientific programs to implement relaxation methods for numerical simulation and signal processing. Such loops iteratively modify the same array elements over different time steps, which presents opportunities for the compiler to improve the temporal data locality through loop tiling. This article presents a compiler framework for automatic tiling of iterative stencil loops, with the objective of improving the cache performance. The article first presents a technique which allows loop tiling to satisfy data dependences in spite of the difficulty created by imperfectly nested inner loops. It does so by skewing the inner loops over the time steps and by applying a uniform skew factor to all loops at the same nesting level. Based on a memory cost analysis, the article shows that the skew factor must be minimized at every loop level in order to minimize cache misses. A graph-theoretical algorithm, which takes polynomial time, is presented to determine the minimum skew factor. Furthermore, the memory-cost analysis derives the tile size which minimizes capacity misses. Given the tile size, an efficient and general array-padding scheme is applied to remove conflict misses. Experiments were conducted on 16 test programs and preliminary results showed an average speedup of 1.58 and a maximum speedup of 5.06 across those test programs.
A discriminative HMM/N-gram-based retrieval approach for mandarin spoken documents
Authors: Chen Berlin , Wang Hsin-Min , Lee Lin-Shan
Published: January 2005

In recent years, statistical modeling approaches have steadily gained in popularity in the field of information retrieval. This article presents an HMM/N-gram-based retrieval approach for Mandarin spoken documents. The underlying characteristics and the various structures of this approach were extensively investigated and analyzed. The retrieval capabilities were verified by tests with word- and syllable-level indexing features and comparisons to the conventional vector-space model approach. To further improve the discrimination capabilities of the HMMs, both the expectation-maximization (EM) and minimum classification error (MCE) training algorithms were introduced in training. Fusion of information via indexing word- and syllable-level features was also investigated. The spoken document retrieval experiments were performed on the Topic Detection and Tracking Corpora (TDT-2 and TDT-3). Very encouraging retrieval performance was obtained.
Example-based sentence reduction using the hidden markov model
Authors: Nguyen Minh Le , Horiguchi Susumu , Shimazu Akira , Ho Bao Tu
Published: January 2005

Sentence reduction is the removal of redundant words or phrases from an input sentence by creating a new sentence in which the gist of the original meaning of the sentence remains unchanged. All previous methods required a syntax parser before sentences could be reduced; hence it was difficult to apply them to a language with no reliable parser. In this article we propose two new sentence-reduction algorithms that do not use syntactic parsing for the input sentence. The first algorithm, based on the template-translation learning algorithm, one of example-based machine-translation methods, works quite well in reducing sentences, but its computational complexity can be exponential in certain cases. The second algorithm, an extension of the template--translation algorithm via innovative employment of the Hidden Markov model, which uses the set of template rules learned from examples, can overcome this computation problem. Experiments show that the proposed algorithms achieve acceptable results in comparison to sentence reduction done by humans.
The obstacles and myths of usability and software engineering
Authors: Seffah Ahmed , Metzker Eduard
Published: January 2005

Avoiding the usability pitfalls involved in managing the software development life cycle.
Software development teams
Authors: Sawyer Steve
Published: January 2005

Considering three software development team archetypes and their implications.
E-commerce and tourism
Authors: Werthner Hannes , Ricci Francesco
Published: January 2005

Travel and tourism are illustrating how e-commerce can change the structure of an industry---and in the process create new business opportunities.
Wireless infidelity II
Authors: Berghel Hal , Uecker Jacob
Published: January 2005

Assessing the extent of the security risks involved in wireless networking technology by considering three possible scenarios demonstrating vulnerabilities.
Like it or not, web services are distributed objects
Authors: Birman Kenneth P.
Published: January 2005

Despite the push to adopt Web services as the universal OO architecture, the Web services reliability model ignores many real-world issues routinely encountered by users.
Structure and evolution of blogspace
Authors: Kumar Ravi , Novak Jasmine , Raghavan Prabhakar , Tomkins Andrew
Published: January 2005

A critical look at more than one million bloggers and the individual entries of some 25,000 blogs reveals blogger demographics, friendships, and activity patterns over time.
Why we blog
Authors: Nardi Bonnie A. , Schiano Diane J. , Gumbrecht Michelle , Swartz Luke
Published: January 2005

Bloggers are driven to document their lives, provide commentary and opinions, express deeply felt emotions, articulate ideas through writing, and form and maintain community forums.
How blogging software reshapes the online community
Authors: Blood Rebecca
Published: January 2005

Spurred by easy-to-use commercial software, blogging is less about creating links and references to sites and sources, and increasingly about bloggers' own comments and personal interests.
Democracy and filtering
Authors: Sunstein Cass R.
Published: January 2005

The Web gives us the ability to filter out unwanted noise and to create our own personal echo chambers---but democracy itself means each of us should be exposed to new topics and contrary opinions.
From the chair
Authors: Sipior Janice C. , Schatzberg Laurie , Leidner Dorothy , Lending Diane , Vowels Susan
Published: January 2005

I would like to extend a warm invitation to you and your invited guests to attend "The Fourth Annual ACM-SIGMIS Reception," to be held as an ACM-SIGMIS event prior to the International Conference on Information Systems (ICIS2004) in Washington, D.C. USA, December 12--15, 2004. Light refreshments will be served.

What: Fourth Annual ACM-SIGMIS Reception

Where: International Conference on Information Systems (ICIS2004) Washington, D.C. USA Grand Hyatt Washington Room to be announced

When: 6:00 to 8:00 pm Saturday, December 11, 2004

Who: All ACM-SIGMIS members and their invited guests are welcome

Please consider hosting a future SIGMIS CPR (Computer Personnel Research) Conference. We are currently accepting Calls For Proposals for the SIGMIS CPR'06 Conference. Let's make the SIGMIS CPR Conference a continuing success! If you are interested, please email me (janice.sipior@villanova.edu) to briefly provide insight about your interest, potential locations, potential conference committee members, potential themes if you have any, and any other relevant information. For your reference, the website for CPR'04 held April 22-24, 2004 in Tucson, AZ USA was: http://monet.ecom.arizona.edu/~misweb/cgi-bin/transition/web/sigmis2004

The Call For Papers for SIGMIS CPR'05, to be held April 14-16, 2005 in Atlanta, GA USA can be found at: http://www.acm.org/sigmis/CFP2005.html

Finally, I would like to encourage you to become an officer of SIGMIS. The slate of candidates for Chair, Vice Chair, and Secretary/Treasurer is to be sent to ACM headquarters by December 1, 2004. If you would like to run for office, please email the following information to George Kasper (gmkasper@vcu.edu), Chair of the Nominating Committee:
The office for which you are a candidate

Name

Address (current and future if an address change is expected before elections are completed)

Phone

Email address

ACM Membership Number
 Candidate's name as it appears on the ACM Membership Roster

Thank you for your continued support of SIGMIS. Your comments and suggestions are encouraged. Please feel free to contact any one of us.

We look forward to seeing you at ICIS'04!
Approaches to fault-tolerant and transactional mobile agent execution---an algorithmic view
Authors: Pleisch Stefan , Schiper André
Published: January 2005

Over the past years, mobile agent technology has attracted considerable attention, and a significant body of literature has been published. To further develop mobile agent technology, reliability mechanisms such as fault tolerance and transaction support are required. This article aims at structuring the field of fault-tolerant and transactional mobile agent execution and thus at guiding the reader to understand the basic strengths and weaknesses of existing approaches. It starts with a discussion on providing fault tolerance in a system in which processes simply fail. For this purpose, we first identify two basic requirements for fault-tolerant mobile agent execution: (1) non-blocking (i.e., a single failure does not prevent progress of the mobile agent execution) and (2) exactly-once (i.e., multiple executions of the agent are prevented). This leads us to introduce the notion of a local transaction as the basic building block for fault-tolerant mobile agent execution and to classify existing approaches according to when and by whom the local transactions are committed. In a second part, we show that transactional mobile agent execution additionally ensures execution atomicity and present a survey of existing approaches. In the last part of the survey, we extend the notion of fault tolerance to arbitrary Byzantine failures and security-related issues of the mobile agent execution.
Replication for web hosting systems
Authors: Sivasubramanian Swaminathan , Szymaniak Michal , Pierre Guillaume , Steen Maarten van
Published: January 2005

Replication is a well-known technique to improve the accessibility of Web sites. It generally offers reduced client latencies and increases a site's availability. However, applying replication techniques is not trivial, and various Content Delivery Networks (CDNs) have been created to facilitate replication for digital content providers. The success of these CDNs has triggered further research efforts into developing advanced Web replica hosting systems. These are systems that host the documents of a website and manage replication automatically. To identify the key issues in designing a wide-area replica hosting system, we present an architectural framework. The framework assists in characterizing different systems in a systematic manner. We categorize different research efforts and review their relative merits and demerits. As an important side-effect, this review and characterization shows that there a number of interesting research questions that have not received much attention yet, but which deserve exploration by the research community.
What’s on Your Hard Drive?
Authors: Grossman Edward
Published: January 2005

Most of my work is prototyping. Perl allows me to quickly put together a prototype of a sophisticated system and pass the design on to someone else to refine. I can quickly accomplish a lot in a few lines of code.
There’s Still Some Life Left in Ada
Authors: Wolfe Alexander
Published: January 2005

Ada remains the Rodney Dangerfield of computer programming languages, getting little respect despite a solid technical rationale for its existence. Originally pressed into service by the U.S. Department of Defense in the late 1970s, these days Ada is just considered a remnant of bloated military engineering practices.
A Conversation with Mike Deliman
Authors: Neville-Neil George
Published: January 2005

Mike Deliman was pretty busy last January when the Mars rover Spirit developed memory and communications problems shortly after landing on the Red Planet. He is a member of the team at Wind River Systems who created the operating system at the heart of the Mars rovers, and he was among those working nearly around the clock to discover and solve the problem that had mysteriously halted the mission on Mars.
Calendar
Authors: Grossman Edward
Published: January 2005

WebSphere Technical Exchange
The Burning Bag of Dung and Other Environmental Antipatterns
Authors: Laplante Phillip
Published: January 2005

In my youth a favorite prank of the local delinquents was to place a paper bag full of doggy doo on a neighbor’s porch, light it on fire, ring the doorbell, and then flee. The home-owner, upon answering the door, had no choice but to stomp out the incendiary feces, getting their shoes dirty in the process. Why this scatological anecdote? Because it is a metaphor for work situations in which things have gotten so bad that the only way to “put the fire out” is to step into it. I call this the “burning bag of dung” antipattern.
The Magic of RFID
Authors: Want Roy
Published: January 2005

Many modern technologies give the impression they work by magic, particularly when they operate automatically and their mechanisms are invisible. A technology called RFID (radio frequency identification), which is relatively new to the mass market, has exactly this characteristic and for many people seems a lot like magic. RFID is an electronic tagging technology that allows an object, place, or person to be automatically identified at a distance without a direct line-of-sight, using an electromagnetic challenge/response exchange. Typical applications include labeling products for rapid checkout at a point-of-sale terminal, inventory tracking, animal tagging, timing marathon runners, secure automobile keys, and access control for secure facilities.
Integrating RFID
Authors: Sarma Sanjay
Published: January 2005

RFID (radio frequency identification) has received a great deal of attention in the commercial world over the past couple of years. The excitement stems from a confluence of events. First, through the efforts of the former Auto-ID Center and its sponsor companies, the prospects of low-cost RFID tags and a networked supply chain have come within reach of a number of companies. Second, several commercial companies and government bodies, such as Wal-Mart and Target in the United States, Tesco in Europe, and the U.S. Department of Defense, have announced RFID initiatives in response to technology improvements.
Thread Scheduling in FreeBSD 5.2
Authors: McKusick Marshall Kirk , Neville-Neil George V.
Published: January 2005

A busy system makes thousands of scheduling decisions per second, so the speed with which scheduling decisions are made is critical to the performance of the system as a whole. This article - excerpted from the forthcoming book, “The Design and Implementation of the FreeBSD Operating System“ - uses the example of the open source FreeBSD system to help us understand thread scheduling. The original FreeBSD scheduler was designed in the 1980s for large uniprocessor systems. Although it continues to work well in that environment today, the new ULE scheduler was designed specifically to optimize multiprocessor and multithread environments. This article first studies the original FreeBSD scheduler, then describes the new ULE scheduler. The article does not describe the realtime scheduler that is also available in FreeBSD.
Trials and Tribulations of Debugging Concurrency
Authors: Gatlin Kang Su
Published: January 2005

We now sit firmly in the 21st century where the grand challenge to the modern-day programmer is neither memory leaks nor type issues (both of those problems are now effectively solved), but rather issues of concurrency. How does one write increasingly complex programs where concurrency is a first-class concern. Or even more treacherous, how does one debug such a beast? These questions bring fear into the hearts of even the best programmers.
A Linux networking study
Authors: Serral René , Gil Marisa
Published: January 2005

The fast evolution and increase in use of nowadays networks forces researchers to look for efficient ways of managing all the information that travels through those networks. Added to that, the growing use of Linux as main operating system for servers and big grid computing farms, has developed many research lines for increasing the networking capabilities and efficiency of the kernel code.

Having that in mind, this document shows the basic internals of the networking code of Linux kernel and discusses the efficiency of the existing implementation in the 2.6 version. Besides, various tests are done for detecting existing bottlenecks in the networking core. Finally are also exposed guidelines for improving certain aspects of the kernel networking behaviour.
A dynamic distributed replica management mechanism based on accessing frequency detecting
Authors: Xu Zhou , Xianliang Lu , Mengshu Hou , Jin Wu
Published: January 2005

This paper presents a novel decentralized dynamic replication management mechanism based on accessing frequency detecting (FDRM).In FDRM, in order to provide better system performance and reduce network traffic, system node scans the local replica of a certain file to detect its access pattern, and makes decision independently to add, delete or migrate a replica for that file. In addition, the scanning interval of a replica is variable according to the accessing frequency to that replica, which makes FDRM more sensitive to the change of system behavior, and we can get better performance with less system overhead. In the end, the paper evaluates the efficiency of FSRM by experimental result and shows the performance enhancement.
Improved conference key distribution protocol based on a symmetric balanced incomplete block design
Authors: Lee Tian-Fu , Hwang Tzonelih
Published: January 2005

An identity-based conference key distribution protocol based on SBIBD was proposed by Chung et al. in 2002 [1]. However, this protocol suffers several problems. Consequently, participants cannot correctly authenticate one another and cannot calculate the same conference key. This study investigates these problems and proposes an improved protocol also based on SBIBD.
An improvement on a deniable authentication protocol
Authors: Chang Ya-Fan , Chang Chin-Chen , Kao Chia-Lin
Published: January 2005

In 2002, Fan et al. proposed a deniable authentication protocol based on the Deffie-Hellman key agreement protocol. They guaranteed that the proposed protocol, which is deniable, can authenticate the source of the message and resist the person-in-the-middle(PIM) attack. However, the receiver is not authenticated in the proposed deniable authentication protocol, which will result in some security flaws. As a result, we propose an improvement to overcome these drawbacks in this paper.
A key authentication scheme with non-repudiation
Authors: Hwang Min-Shiang , Li Li-Hua , Lee Cheng-Chi
Published: January 2005

In 1996, Horng and Yang proposed a key authentication scheme that requires no authorities. However, it is vulnerable to the guessing attack. An intruder can try out a password and forge the public key. To amend this problem, an improved authentication scheme intended to prevent the guessing attack and the forging problem was proposed by Zhan et al. in 1999. However, their scheme did not achieve non-repudiation of public key. In order to achieve non-repudiation of public key, two improvements of key authentication scheme for non-repudiation are discussed in this paper.
A secure and efficient strong-password authentication protocol
Authors: Chang Ya-Fen , Chang Chin-Chen
Published: January 2005

Password authentication protocols are divided into two types. One employs the easy-to-remember password while the other requires the strong password. In 2001, Lin et al. proposed an optimal strong-password authentication protocol (OSPA) to resist the replay attack and the denial-of-service attack. However, Chen and Ku pointed out that the OSPA protocol is vulnerable to the stolen-verifier attack. Hence, Lin et al. presented an enhancement in 2003. Nevertheless, mutual authentication is not ensured in Lin et al.'s protocol such that it suffers from the server spoofing attack. Moreover, Lin et al.'s protocol is also vulnerable to the denial-of-service attack. As a result, we present a secure strong-password authentication protocol in this paper to overcome their disadvantages.
The Guru Code
Authors: Grossman Edward
Published: January 2005

No, this is not my attempt at a Da Vinci Code parody. The guru code isn’t fiction, it’s real. The guru code permeates everything—OK, maybe not everything, but at least the cable TV network in Connecticut.
Letters
Authors: Grossman Edward
Published: January 2005

Here’s my favorite definition of class: “A class is a module AND a blueprint for modules. The modules constructed according to such a blueprint are usually called ‘objects of the class’.”
News 2.0
Authors: Stanik John
Published: January 2005

You’ve probably been reading a lot about the PlanetLab Consortium (150-universities-and-research-labs-large, and growing) and all the bells and whistles that will be included in the new, planetary-scale Internet, such as a new overlay network with intelligent routers and servers, decentralized and self-organizing applications, higher-level functionalities, and more. Sounds like something that most of earth’s 6 billion mortals could get used to.
Kode Vicious Strikes Again
Authors: Neville-Neil George
Published: January 2005

Dear Kode Vicious, I have this problem. I can never seem to find bits of code I know I wrote. This isn’t so much work code--that’s on our source server--but you know, those bits of test code I wrote last month, I can never find them. How do you deal with this?
Review: Wi-Foo: The Secrets of Wireless Hacking
Authors: Puzmanova Rita
Published: January 2005

Review: Wi-Foo: The Secrets of Wireless Hacking
Review: Network Distributed Computing: Fitscapes and Fallacies
Authors: Kohlhepp Bayard
Published: January 2005

Review: Network Distributed Computing: Fitscapes and Fallacies
Calendar
Authors: Grossman Edward
Published: January 2005

Supercomputing. November 6-12, 2004. Pittsburgh, Pennsylvania. RFID Developer Conference. November 9-10, 2004. San Francisco, California
Careers
Authors: Grossman Edward
Published: January 2005

NextNet,the industry’s most widely deployed provider of non-line-of-sight (NLOS) plug-and-play broadband wireless access systems has an immediate opening for a Software Engineer. This position will be responsible for the design, development and support of RISC based embedded software for interfacing to proprietary signal processing devices and microprocessor support chips.
Programming in Franglais
Authors: Bates Rodney
Published: January 2005

When I was studying French in high school, we students often spoke “Franglais”: French grammar and words where we knew them, English inserted where our command of French failed us. It was pretty awful, and the teacher did not think highly of it. But we could communicate haltingly because we all had about the same levels of knowledge of the respective languages. Today, there is a kind of programmer’s Franglais that is all too pervasive. Those who are old enough will remember the pitched controversy in the late 1960s and early 1970s over whether compilers, operating systems, and other systems programs should be written in assembly code or a high-level language. The prime argument for the languages was that their higher-level computational model allowed far more function to be coded in the same amount of development time.
Automating Software Failure Reporting
Authors: Murphy Brendan
Published: January 2005

There are many ways to measure quality before and after software is released. For commercial and internal-use-only products, the most important measurement is the user’s perception of product quality. Unfortunately, perception is difficult to measure, so companies attempt to quantify it through customer satisfaction surveys and failure/behavioral data collected from its customer base. This article focuses on the problems of capturing failure data from customer sites. To explore the pertinent issues I rely on experience gained from collecting failure data from Windows XP systems, but the problems you are likely to face when developing internal (noncommercial) software should not be dissimilar.
Error Messages
Authors: Maglio Paul P. , Kandogan Eser
Published: January 2005

Computer users spend a lot of time chasing down errors - following the trail of clues that starts with an error message and that sometimes leads to a solution and sometimes to frustration. Problems with error messages are particularly acute for system administrators (sysadmins) - those who configure, install, manage, and maintain the computational infrastructure of the modern world - as they spend a lot of effort to keep computers running amid errors and failures.
Outsourcing: Devising a Game Plan
Authors: Kolawa Adam
Published: January 2005

Your CIO just summoned you to duty by handing off the decision-making power about whether to outsource next years big development project to rewrite the internal billing system. That’s quite a daunting task! How can you possibly begin to decide if outsourcing is the right option for your company? There are a few strategies that you can follow to help you avoid the pitfalls of outsourcing and make informed decisions. Outsourcing is not exclusively a technical issue, but it is a decision that architects or development managers are often best qualified to make because they are in the best position to know what technologies make sense to keep in-house. Deciding what should and should not be outsourced is key to a successful game plan.
Lack of Priority Queuing Considered Harmful
Authors: Gill Vijay
Published: January 2005

Most modern routers consist of several line cards that perform packet lookup and forwarding, all controlled by a control plane that acts as the brain of the router, performing essential tasks such as management functions, error reporting, control functions including route calculations, and adjacency maintenance. This control plane has many names; in this article it is the route processor, or RP. The route processor calculates the forwarding table and downloads it to the line cards using a control-plane bus. The line cards perform the actual packet lookup and forwarding. Although individual vendors or models may differ slightly in implementation, the salient points remain the same.
TCP-friendly marking for scalable best-effort services on the internet
Authors: Monaco Giampiero Lo , Feroz Azeem , Kalyanaraman Shivkumar , Xia Yong
Published: January 2005

This paper proposes the use of TCP-aware network-based packet marking, which in conjunction with differential packet dropping, is a powerful way to improve the performance of buffer management for best-effort services on the Internet. We extend the notion of "TCP-Friendly" packet marking, proposed recently by us [6], and apply it to improve the performance of traditional best-effort services. The TCP-aware use of deterministic packet marking at the network edge allows us to protect selected TCP packets from suffering loss. This significantly reduces the total number of timeouts and avoids the resulting service degradation. In particular, we protect TCP sessions with very small windows, disperse packet loss across a given window, and protect retransmitted packets from encountering loss. We show baseline results which illustrate that the performance gains are considerable (orders of magnitude) when compared to stateful packet dropping algorithms like FRED [15], and even when TCP SACK [18] implementations are employed. The scheme has been implemented in Linux 2.2.10, and all the results are based upon experimental data.
An adaptive per-host IP paging architecture
Authors: Castelluccia Claude , Mutaf Pars
Published: January 2005

IP Paging has received considerable attention recently. The IETF has decided to develop an IP Paging protocol and some IP Paging protocols have been proposed by researchers [13, 12]. However all of these proposals use static and manually configured paging areas. We argue that the size and the shape of paging areas are very critical for the performance of a paging system. A system that allows each host to use a paging area that adapts to its mobility and communication patterns will perform better. This paper proposes to extend the IETF IP Paging functional architecture to support adaptive and per-host paging areas. We introduce a new functional module, the Paging Area Configuration Agent (PACA), that automatically configures the paging area relative to each cell of a cellular domain.
Analysis and modeling of F0 contours for cantonese text-to-speech
Authors: Li Yujia , Lee Tan , Qian Yao
Published: January 2005

For the generation of highly natural synthetic speech, the control of prosody is of primary importance. The fundamental frequency (F0) is one of the most important components of speech prosody. This research investigates the variation of F0 in continuous Cantonese speech, with the goal of establishing an effective mechanism of prosody control in Cantonese text-to-speech (TTS) applications. Cantonese is a commonly used Chinese dialect that is well known for being rich in tones. This article describes a simple yet effective approach to the analysis and modeling of F0. The surface F0 contour of a continuous Cantonese utterance is considered to be the combination of a global component--phrase-level intonation curve, and local components--syllable-level tone contoursA novel method of F0 normalization is proposed to separate the local components from the global one. As a result, the variation in tone contours is greatly reduced. Statistical analysis is performed for the phrase curves and context-dependent tone contours that are extracted from a large corpus of 1,200 utterances. Specifically, the analysis is focused on co-articulated tone contours for disyllabic words, cross-word contours, and phrase-initial tone contours. Based on the results of the analysis, a template-based model for F0 generation is established and integrated with a Cantonese TTS system. Subjective listening tests show that the proposed model significantly improves the naturalness of the output speech.
Trends for 2005
Authors: Weiss Aaron
Published: January 2005

A fractured landscape of technological innovations reveals that now, more than ever, we're all connected
Search party
Authors: Schindler Esther
Published: January 2005

Innovations abound as the traditional Web-based "search" moves into uncharted territory
How to build a supercomputer
Authors: Treese Win
Published: January 2005

For many people, the word "supercomputer" conjures an image of a giant machine in a special room, feverishly computing solutions to the esoteric problems of scientific research, weather prediction, or perhaps even the secrets of spy agencies. At one time, about 20 years ago, that was indeed what it meant. Today, however, what makes a supercomputer has changed, and one of the key changes is using a network.
Programming with transactional coherence and consistency (TCC)
Authors: Hammond Lance , Carlstrom Brian D. , Wong Vicky , Hertzberg Ben , Chen Mike , Kozyrakis Christos , Olukotun Kunle
Published: January 2005

Transactional Coherence and Consistency (TCC) offers a way to simplify parallel programming by executing all code within transactions. In TCC systems, transactions serve as the fundamental unit of parallel work, communication and coherence. As each transaction completes, it writes all of its newly produced state to shared memory atomically, while restarting other processors that have speculatively read stale data. With this mechanism, a TCC-based system automatically handles data synchronization correctly, without programmer intervention. To gain the benefits of TCC, programs must be decomposed into transactions. We describe two basic programming language constructs for decomposing programs into transactions, a loop conversion syntax and a general transaction-forking mechanism. With these constructs, writing correct parallel programs requires only small, incremental changes to correct sequential programs. The performance of these programs may then easily be optimized, based on feedback from real program execution, using a few simple techniques.
Deconstructing storage arrays
Authors: Denehy Timothy E. , Bent John , Popovici Florentina I. , Arpaci-Dusseau Andrea C. , Arpaci-Dusseau Remzi H.
Published: January 2005

We introduce Shear, a user-level software tool that characterizes RAID storage arrays. Shear employs a set of controlled algorithms combined with statistical techniques to automatically determine the important properties of a RAID system, including the number of disks, chunk size, level of redundancy, and layout scheme. We illustrate the correctness of Shear by running it upon numerous simulated configurations, and then verify its real-world applicability by running Shear on both software-based and hardware-based RAID systems. Finally, we demonstrate the utility of Shear through three case studies. First, we show how Shear can be used in a storage management environment to verify RAID construction and detect failures. Second, we demonstrate how Shear can be used to extract detailed characteristics about the individual disks within an array. Third, we show how an operating system can use Shear to automatically tune its storage subsystems to specific RAID configurations.
HIDE
Authors: Zhuang Xiaotong , Zhang Tao , Pande Santosh
Published: January 2005

XOM-based secure processor has recently been introduced as a mechanism to provide copy and tamper resistant execution. XOM provides support for encryption/decryption and integrity checking. However, neither XOM nor any other current approach adequately addresses the problem of information leakage via the address bus. This paper shows that without address bus protection, the XOM model is severely crippled. Two realistic attacks are shown and experiments show that 70% of the code might be cracked and sensitive data might be exposed leading to serious security breaches.Although the problem of address bus leakage has been widely acknowledged both in industry and academia, no practical solution has ever been proposed that can provide an adequate security guarantee. The main reason is that the problem is very difficult to solve in practice due to severe performance degradation which accompanies most of the solutions. This paper presents an infrastructure called HIDE (Hardware-support for leakage-Immune Dynamic Execution) which provides a solution consisting of chunk-level protection with hardware support and a flexible interface which can be orchestrated through the proposed compiler optimization and user specifications that allow utilizing underlying hardware solution more efficiently to provide better security guarantees.Our results show that protecting both data and code with a high level of security guarantee is possible with negligible performance penalty (1.3% slowdown).
HOIST
Authors: Regehr John , Reid Alastair
Published: January 2005

Embedded software must meet conflicting requirements such as be-ing highly reliable, running on resource-constrained platforms, and being developed rapidly. Static program analysis can help meet all of these goals. People developing analyzers for embedded object code face a difficult problem: writing an abstract version of each instruction in the target architecture(s). This is currently done by hand, resulting in abstract operations that are both buggy and im-precise. We have developed Hoist: a novel system that solves these problems by automatically constructing abstract operations using a microprocessor (or simulator) as its own specification. With almost no input from a human, Hoist generates a collection of C func-tions that are ready to be linked into an abstract interpreter. We demonstrate that Hoist generates abstract operations that are cor-rect, having been extensively tested, sufficiently fast, and substan-tially more precise than manually written abstract operations. Hoist is currently limited to eight-bit machines due to costs exponential in the word size of the target architecture. It is essential to be able to analyze software running on these small processors: they are important and ubiquitous, with many embedded and safety-critical systems being based on them.
Helper threads via virtual multithreading on an experimental itanium
®
2 processor-based platform
Authors: Wang Perry H. , Collins Jamison D. , Wang Hong , Kim Dongkeun , Greene Bill , Chan Kai-Ming , Yunus Aamir B. , Sych Terry , Moore Stephen F. , Shen John P.
Published: January 2005

Helper threading is a technology to accelerate a program by exploiting a processor's multithreading capability to run ``assist'' threads. Previous experiments on hyper-threaded processors have demonstrated significant speedups by using helper threads to prefetch hard-to-predict delinquent data accesses. In order to apply this technique to processors that do not have built-in hardware support for multithreading, we introduce virtual multithreading (VMT), a novel form of switch-on-event user-level multithreading, capable of fly-weight multiplexing of event-driven thread executions on a single processor without additional operating system support. The compiler plays a key role in minimizing synchronization cost by judiciously partitioning register usage among the user-level threads. The VMT approach makes it possible to launch dynamic helper thread instances in response to long-latency cache miss events, and to run helper threads in the shadow of cache misses when the main thread would be otherwise stalled.The concept of VMT is prototyped on an Itanium
®
2 processor using features provided by the Processor Abstraction Layer (PAL) firmware mechanism already present in currently shipping processors. On a 4-way MP physical system equipped with VMT-enabled Itanium 2 processors, helper threading via the VMT mechanism can achieve significant performance gains for a diverse set of real-world workloads, ranging from single-threaded workstation benchmarks to heavily multithreaded large scale decision support systems (DSS) using the IBM DB2 Universal Database. We measure a wall-clock speedup of 5.8% to 38.5% for the workstation benchmarks, and 5.0% to 12.7% on various queries in the DSS workload.