bluuebunny/crossref_metadata_2025 huggingface dataset:
Introductory course in human computer interaction
Authors: Strong G. W.
Published: January 2007

This is a course outline of an undergraduate course in the Information Systems program at Drexel University. It is usually taken during the third term of the Freshman year after two introductory courses in information systems and two courses in computer programming. Since students at Drexel are required to own or have access to a Macintosh computer during their first term, they are familiar with the Macintosh interface before this course is taken.
Human factors in teaching
Authors: Sharpe D. , Willshire M. J.
Published: January 2007

In this paper we discuss the parallels between human factors in computer systems and human factors in the classroom. We look at some of the human factors guidelines for computer system design and discuss their analogs in course design and execution. Since many of us are called upon to share our expertise in a classroom setting, perhaps we can learn from our experience with software and thus try to maximize our teaching effectiveness.
Corporate contributions: Is the tail wagging the dog?
Authors: Draper M. , Lutz R. W. , Nicholson J.
Published: January 2007

Nicholson: Before I go directly to my argument that the tail is not wagging the dog, let me share with you a little information about Howard University and how computing fits into the overall organization.
3D scene on 2D screen: the VISUALCAD connection
Authors: Kodali N.
Published: January 2007

Working with 3D space through the 2D computer screen is a skill that has to be mastered by CAD users. Current user interface designs fail to address the basic issue of relating the users' mental space with the computer's construction space. VISUALCAD, a new technique developed to communicate 3D CAD concepts, combines the users' mental space and the computers construction space. Through the use of video tools it enables us to discuss and demonstrate the key concepts in CAD all in one real space. The use of video is found to be an indispensable part of CAD training.
Improving aviation accident research through the use of video
Authors: Armstrong Herbert B.
Published: January 2007

The investigation and analysis of aviation accidents is a critical aspect of aviation safety and a major tool for aviation system improvement. The National Transportation Safety Board is charged with the responsibility of determining the probable cause of aviation accidents, identifying contributing factors, and making recommendations for changes to equipment or procedures as a result of their investigations. The intent is to identify what went wrong and prevent its recurrence -- to learn from the errors of others and, thus, save lives and property.
VIDEO: a design medium
Authors: Harrison Steve , Minneman S. , Stults B. , Weber K.
Published: January 2007

We use video to support design. By design, we (the Design and Media Spaces Area at Xerox PARC) mean the creation of the new, whether it is architecture, painting, or engineering. We believe that design is a social activity---the interactions of individuals within a group and the relation of groups to one another. Another way we express this point of view is to say design is the social construction of a technical reality. We seek to improve design processes by enabling better communications within the design process.
Integrating motion into computational environments
Authors: Michon B.
Published: January 2007

Motion video in the computation environment is a major step in the evolution of expressive and effective computer systems. However, video is a difficult medium to integrate into a professional workstation or a personal computer. This true from the base video mixing architecture to the functional design of the user interface.
The use of video in organizational studies
Authors: Allen C.
Published: January 2007

In this paper I discuss the use of video in organizational studies, in particular, studies which are characterized by long term observation of a group or organization. These studies are different than many other types of investigation of human behavior in that they occur in uncontrolled circumstances. In the past I've used video for the study of designers at work on specific tasks, including graphic designers and typographers working for periods between an hour and six hours. In each of these cases, all of the activity occurred within the confines of a certain time and in a place where the video was continuously available and in use. In contrast, the work that occurs within an organization happens across a number of people and locations. Interaction happens not only in meeting rooms and at desks, but also in the hallways, at lunch, and in bathrooms, places where video may not always be appropriate or available.
Book review: Rule Based Programming with OPS5 by Thomas A. Cooper and Nancy Wogrin (Morgan Kaufmann Pubtishers)
Authors: Trowbridge Timothy L.
Published: January 2007

"Rule Based Programming with OPS5" is intended for beginning OPS5 programmers and, according to the foreword by John McDermott, presents "... the collective wisdom of experienced OPS5 programmers ..." to enable those beginners to avoid common mistakes and misuse of the language. The authors assume that the reader is familiar with software development fundamentals such as data structures and data abstraction, however, experience with production systems, rule-based programming, expert systems or even artificial intelligence is not needed. Nonetheless the methods presented in the text are flavored for expert system developers.
Use of structure-based models in the development of expert systems
Authors: Ramirez J. G.
Published: January 2007

The Knowledge representation method plays an important role in the way the knowledge is accessed and used; thats the reason why the Knowledge representation is the key factor in the expert systems or Knowledge based systems development.
Special function integration
Authors: Piquette J. C.
Published: January 2007

This article describes a method by which the integration capabilities of symbolic-mathematics computer programs can be extended to include integrals that contain special functions. A summary of the theory that forms the basis of the method is given in Appendix A. A few integrals that have been evaluated using the method are presented in Appendix B. A more thorough development and explanation of the method is given in Piquette, in review (b).
Microprogrammed Architectures Specified using PAISLey (A description of an ongoing project)
Authors: Habib Stanley
Published: January 2007

Operational specification is a method of documenting specifications for systems which separates the implementation details from the problem requirements details. Operational specification permits simulation of the specification enabling the specification creator to test the specification to see how well it satisfies prescribed functional requirements. The line between specification and description when applied to computer architecture design is rather thin in my opinion and the experience of this author indicates that a particular specification tool known as PAISLey (described in more detail below) can serve as a suitable hardware description tool.
AI factory scheduling: multiple problem formulations
Authors: Stokey R. J.
Published: January 2007

Included in this book is a review of research and applications as well as a presentation of new results. There is a mix of papers from industry, research laboratories and academia which gives a realistic perspective on the prospoects for AI technology in PMS applications. The majority of papers are concerned with the use of knowledge-based techniques to solve various scheduling problems. The introductory section includes two overview papers, each presenting the views and expectations of researchers in major industrial companies who have some experience of using AI technology to solve production management problems. There follows a series of technical papers which have been grouped into five categories: model based and simulation approaches; AI and scheduling; AI and production planning; the GRAI method; AI applications and FMS.
The RM-CELL vs. the earthquakes
Authors: de la Pena Casares B.
Published: January 2007

This paper describes an attempt to forecast earthquakes using the RM-CELL [1]. The paper relates in an abreviated form how the research was developed and the unexpected final result: It seems that large earthquakes can be detected during its growing stage.
Crafting Knowledge Based Systems Expert Systems Made Realistic by Waiters and Nielson (Wiley Interscience, 1988)
Authors: Singer Robin
Published: January 2007

When professional recruiters post sexy advertisements to lure engineers and computer scientists to their agencies, they often claim to know of exciting new jobs in Expert Systems. For several years, Artificial Intelligence and its subspeciality, Expert Systems, have been among the "hottest" of the "hot" computer fields. The cynical observer might suspect that Walters and Nielson, and Wiley Interscience, authors and publisher respectively of "Crafting Knowledge Based Systems, Expert Systems Made Realistic" were attempting to capitalize on this overwhelming Expert Systems craze.
Storing a tree structure by using decimal notation
Authors: Aoe J. I.
Published: January 2007

A decimal notation satisfies many simple mathematical properties, and it is a useful tool in the analysis of trees. A practical method is presented, that compresses the decimal codes while maintaining the fast determination of relations(e.g., ancestor, descendant, brother, etc.). A special node, called a

kernel node

, including many common subcodes of the other codes, is defined, and a compact data structure is presented using the kernel nodes. Let
n
(
m
) be the number of the total(kernel) nodes. It is theoretically proved that encoding a decimal code is a constant time, that the worst-case time complexity of compressing the decimal codes is O(

n
+
m
2

), and that the size of the data structure is proportional to
m.
From the experimental results of some hierarchical semantic primitives for natural language processing, it is shown that the ratio
m/n
becomes an extremely small value, ranging from 0.047 to 0.13.
Retrieving highly dynamic widely distributed information
Authors: Wyle M. F. , Frei h. P.
Published: January 2007

Wide area networks provide a variety of information sources which can be exploited only by appropriate information retrieval techniques such as repeated automatic query of remote databases and bulletin boards. Distinctive features of the content and access methods of information on wide area nets are discussed from an IR perspective. The development, algorithms, and analysis of a functioning system are also presented.
A new approach to text searching
Authors: Baeza-Yates R. A. , Gonnet G. H.
Published: January 2007

We introduce a family of simple and fast algorithms for solving the classical string matching problem, string matching with don't care symbols and complement symbols, and multiple patterns. In addition we solve the same problems allowing up to
k
mismatches. Among the features of these algorithms are that they are real time algorithms, they don't need to buffer the input, and they are suitable to be implemented in hardware.
Multikey access methods based on term discrimination and signature clustering
Authors: Chang J. W. , Lee J. H. , Lee Y. J.
Published: January 2007

In order to improve the two-level signature file method designed by Sacks-Davis et al. [20], we propose new multikey access methods based on term discrimination and signature clustering. By term discrimination, we create separate, efficient access methods for the terms frequently used in user queries. We in addition cluster similar signatures by means of these terms so that we may achieve good performance on retrieval. Meanwhile we provide the space-time analysis of the proposed methods and compare them with the two-level signature file method. We show that the proposed methods achieve 15-30% savings in retrieval time and require 3-9 % more storage overhead.
Settings and the setting structure: the description and automated propagation of networks for perusing videodisk image states
Authors: Parkes A.
Published: January 2007

This paper describes a system for formally representing spatial relationships between videodisc image states called
settings
. A number of
setting relations
are defined, these being based on the manipulations of the camera typically used in the production of the moving film:
zooming in or out, panning
etc.. An algorithm is presented which, given a limited level of initial specification by a describer, will constrain, where possible, the setting relations holding between all pairs of settings. The resulting network is called the
settings structure
. The paper begins by placing the
settings structure
into the context of its being one part of the
CLORIS
system.
A closed network with a discriminatory processor-sharing server
Authors: Mitra D. , Weiss A.
Published: January 2007

This paper gives a simple, accurate first order asymptotic analysis of the transient and steady state behavior of a network which is closed, not product-form and has multiple classes. One of the two nodes of the network is an infinite server and the discipline in the other node is discriminatory processor-sharing. Specifically, if there are

n
j

jobs of class
j
at the latter node, then each class
j
job receives a fraction

w
j
/

(Σ
w
i
n
i
) of the processor capacity. This work has applications to data networks. For the asymptotic regime of high loading of the processor and high processing capacity, we derive the explicit first order transient behavior of the means of queue lengths. We also give explicit expressions for the steady state mean values and a simple procedure for finding the time constants (eigenvalues) that govern the approach to steady state. The results are based on an extension of Kurtz's theorem concerning the fluid limit of Markov processes. Some numerical experiments show that the analysis is quite accurate.
DOAS: an object oriented architecture supporting secure languages
Authors: van de Goor A. J. , Corporaal H.
Published: January 2007

Current software engineering practice heavily relies on the reliability of software implementation languages and underlying architectures. However, both the currently used languages, as well as the traditional architectures suffer from a shortage of built-in security. In this paper, an architecture is presented, which is heavily influenced by two properties of secure languages: coercion and exception handling. It is shown that proper design decisions lead to an architecture having a compact data representation, allowing both generic and nongeneric instructions. The architecture is object oriented, and object addressing is under control of the operand stream, with optimalisation possibilities to bypass descriptor inspection.
Incremental foresighted local compaction
Authors: Wijaya P. , Allan V. H.
Published: January 2007

Under timing constraints, local compaction may fail because of poor scheduling decisions. Su [SDWX87] uses foresight to avoid some of the poor scheduling decisions. However, the foresight takes a considerable amount of time. In this paper the Incremental Foresight algorithm is introduced. Experiments using four different target architectures show that the Incremental Foresight algorithm works as well as foresight, and saves around 48 percent of the excess time.
Microarchitecture choices (implementation of the VAX)
Authors: Patt Yale N.
Published: January 2007

The VAX Architecture provides hardware implementors with an opportunity or a nightmare, depending on your point of view. Such characteristics as 304 opcodes, a large number of addressing modes, a large number of supported data types, and non-regularities in the ISA semantics all provide challenges to the microarchitect. The VAX architecture was introduced in 1977 with its first microarchitecture, the VAX 11/780, a TTL MSI implementation. Since then, there have been several distinct implementations, each reflecting (1) the technology in which it was implemented, (2) the performance/cost tradeoffs it was supposed to consider, and (3) the design methodology of its implementors. This paper is a first attempt at discussing several VAX implementations from the standpoint of the choices made in the microarchitecture as driven by the context of the device technology, the performance/cost tradeoffs, and other considerations.
A model for microarchitecture structure evaluation
Authors: Fernandes E. S. T.
Published: January 2007

This paper presents the specification and implementation of a model oriented primarily to the evaluation of the structure of microarchitectures. According to the model, target architectures are described as an oriented graph which is examined by search algorithms in order to find the minimum cost path required in the execution of a set of machine primitives.

The model is very useful to determine the role of each target machine component: through the model it is possible to assess the effect of both including and removing architecture components on the overall performance of a machine being conceived.

The paper shows the main aspects of the project, discusses the research potential of the model, and describes the current stage of the work.
ASIC microprocessors
Authors: Flynn M. J. , Winner R. I.
Published: January 2007

ASIC microprocessors are becoming an important technology for the control of complex (“embedded”) systems. The advantage of such microprocessors is that they can be tailored to the application. This tailoring is quite non-intuitive and optimization is a complex process. Tools such as the Architect's Workbench (AWB) have been developed to assist in this optimization. An example study shows a more than two to one advantage of such assisted analysis.
Going back in hypertext
Authors: Golovchinsky Gene
Published: January 2007

Hypertext interfaces typically involve navigation, the act (and interaction) of moving from one piece of information to another. Navigation can be exploratory, or it may involve backtracking to some previously-visited node. While backtracking interfaces are common, they may not reflect differences in readers' purposes and mental models. This paper draws on some empirical evidence regarding navigation within documents to suggest an improvement on traditional hypertext navigation, and proposes a time-based model of backtracking.
Rule-based extraction of experimental evidence in the biomedical domain
Authors: Regev Yizhar , Finkelstein-Landau Michal , Feldman Ronen , Gorodetsky Maya , Zheng Xin , Levy Samuel , Charlab Rosane , Lawrence Charles , Lippert Ross A. , Zhang Qing , Shatkay Hagit
Published: January 2007

Below we describe the winning system that we built for the KDD Cup 2002 Task 1 competition. Our system is a Rule-based Information Extraction (IE) system. It combines pattern matching, Natural Language Processing (NLP) tools, semantic constraints based on the domain and the specific task, and a post-processing stage for making the final curation decision based on the various evidence (positive and negative) found within the document. Development and implementation were made using the

DIAL

IE language and the

ClearLab

development environment. The results achieved were significantly superior than those achieved using categorization approaches.
The genomics of a signaling pathway
Authors: Craven Mark
Published: January 2007

This article describes Task 2 of the KDD Cup 2002 datamining competition. The task involved predicting whether deletions of individual genes in a yeast genome would affect a particular signaling pathway in the cell. With its rich data sources and abundance of missing information, the task is representative of data mining problems in genomics and proved to be quite challenging.
KDD-2002 workshop report fractals and self-similarity in data mining
Authors: Adibi Jafar , Faloutsos Christos
Published: January 2007

In this report we provide a summary of the first workshop on application of self-similarity and fractals in data mining: issues and approaches held in conjunction with ACM SIGKDD 2002, July 23 at Edmonton, Alberta, Canada.
GridG
Authors: Lu Dong , Dinda Peter A.
Published: January 2007

A realistic workload is essential in evaluating middleware for computational grids. One important component of that workload is the raw grid itself: an annotated graph representing the network topology and the hardware and software available on each node and link within it. GridG is an extensible synthetic generator of such graphs that is implemented as a series of transformations on a common graph format. The paper provides a definition of and requirements for grid generation. We then describe the GridG process in two steps: topology generation and annotation. For topology generation, we have both a model and a mechanism. We leverage Tiers, an existing tool commonly used in the networking community, but we extend it to produce graphs that conform to recently discovered power laws of Internet topology. We also contribute to the theory of network topology by pointing out a contradiction between two laws, and proposing a new version of one of them. For annotation, we have developed a mechanism, the
requirements
for a model, and identified the open problem of characterizing the distribution and correlation of hardware and software resources on the network.
Contemplations of a simulation navel or recognizing the seers among peers
Authors: Nance Richard E.
Published: January 2007

The Model Development Environment Project has the goal of defining the software utilities and the database support needed for creating, validating, and experimenting with complex simulation models. This project review, emphasizing the needs and explaining some of the guiding concepts and principles, serves to underscore key issues extending beyond discrete event simulation. An introspective summary presents an optimistic reaction to the fear that technically naive modelers might use the more sophisticated capabilities to produce catastrophic results.
Book Review: EXPERT DATABASE SYSTEMS Proceedings from the 2nd Intl. Conference. April 25-27, 1988 Vienna, VA. Edited by Larry Kerschberg (Benjamin/Cummings Publishing Company, 1988)
Authors: Saeed Faisel
Published: January 2007

Expert Database Systems (EDS) has emerged in the recent years as a powerful combination of disciplines like Artificial Intelligence, Database Management, Logic Programming, and Fuzzy System Theory. This new field incorporates the benefits of both data-based and knowledge-based systems and has generated a great interest among the research, industrial and government communities. An International Workshop on EDS was held in South Carolina in October, 1984, which became the initiative for starting a series of International Conferences on EDS. The first conference on EDS was held in April, 1986 in South Carolina. The second conference, EDS'88, was held in Virginia on April 25--27, 1988. This conference was attended by 350 participants from Australia, Belgium, Brazil, Canada, Denmark, Egypt, England, Federal Republic of Germany, France, Ireland, Italy, Japan, Mexico, Netherlands, Singapore, the Soviet Union, Switzerland, and USA.
Design comparisons for procurement systems
Authors: Thomas Charles J. , Wilson Bart J.
Published: January 2007

We use experimental techniques to compare first-price auctions to a common but previously unexamined exchange process that we term "multilateral negotiations." Initially, we find that transaction prices are statistically indistinguishable in the two institutions with four sellers, but that prices are higher in multilateral negotiations than in first-price auctions with two sellers. Surprisingly, we find in two-seller environments that a history of multilateral negotiations leads to higher auction prices, which suggests that buyers may see little price effect by moving from negotiations to auctions.
Efficiency and price discovery in multi-item auctions
Authors: Bansal Vipul , Garg Rahul
Published: January 2007

Distributed multi-item auctions offer great opportunities for integrating fragmented online auction markets into larger markets with more efficient outcomes. We extend the theory of multiitem ascending auctions in a multi-unit demand scenario. We show that a simple greedy bidding strategy results in efficient allocation and unique prices. We also show that the strategy constitutes a Nash Equilibrium of the system with single unit demand. We discuss the implications of our results for the design of auctions on the Internet.
On handling component and transaction failures in multi agent systems
Authors: Varakantham Pradeep Reddy , Gangwani Santosh Kumar , Karlapalem Kamalakar
Published: January 2007

Multi agent systems are being used for various practical applications like e-commerce, e-auctions and gathering information from the web. Thus there is a need for these systems to be robust. However, agents can fail due to component failures. The atomic tasks taken up by the agents might also fail. So, agents need to recover to a correct state after a failure. This paper deals with the logging required and hence forth the recovery protocol to recover the agent to a correct state. An agent is modeled as a colored Petrinet. By logging the state information of the agent (Petrinet) an agent recovers from failures. For atomicity of tasks in multi-agent systems, linear two-phase commit protocol with some enhancements is proposed
Specifying conflict of interest in web services endpoint language (WSEL)
Authors: Hung Patrick C. K.
Published: January 2007

A Web service is an autonomous unit of application logic that provides either some business functionalities or information to other applications through an Internet connection. A business process contains a set of activities, and service locators assign an appropriate Web service for each activity.Recently IBM proposed a new XML language called Web Services Endpoint Language (WSEL) for describing endpoint properties of Web services. Web services will be described through endpoint properties by the appropriate extensibility elements in WSEL in order to facilitate the processes of matchmaking and delegation.It is obvious that security issues are important endpoint properties at Web services.This paper extends the WSEL to specify the conflict of interest in the processes of matchmaking and delegation as one of the endpoint properties.In addition to this, this paper also introduces the concepts of separation of duties and security risk factor in the Web service assignments.
P2P M-commerce in pervasive environments
Authors: Avancha Sasikanth , D'Souza Peter , Perich Filip , Joshi Anupam , Yesha Yelena
Published: January 2007

Pervasive environments are characterized by the presence of wireless devices ranging from sensors to mobile PDA-phones to laptops. Peer-to-Peer (P2P) information sharing in such environments presents a tremendous opportunity for people and devices to exchange information such as music, pictures, documents and stock tickers with peers. Information that has a monetary value introduces a whole new set of problems for P2P interaction in pervasive environments. In this work, we present the design of a middleware that attempts to solve these problems using concepts of the Contract Net Protocol, Semantic Service Discovery and secure transaction protocols.
Abstractions, instantiations, and proofs of marking algorithms
Authors: Yelowitz Lawrence , Duncan Arthur G.
Published: January 2007

A detailed look is taken at the problem of factoring program proofs into a proof of the underlying algorithm, followed by a proof of correct implementation of abstract variables at the concrete level. We do this considering four different concrete “marking” algorithms and formulating a single abstract algorithm and set of abstract specifications that can be instantiated to each of the four concrete cases. An intermediate assertion, as well as sufficient conditions for correct initialization, invariance, and correctness at termination are given at the abstract level. Proofs at the concrete level are then given by exhibiting appropriate mapping functions (from the concrete state vector to the abstract variables), and showing that the sufficient conditions are true. Proofs of termination are given by instantiating “termination schemas”.
The automatic synthesis of recursive programs
Authors: Manna Zohar , Waldinger Richard
Published: January 2007

We describe a deductive technique for the automatic construction of recursive programs to meet given input-output specifications. These specifications express what conditions the output of the desired program is expected to satisfy. The deductive technique involves transforming the specifications by a collection of rules, summoned by pattern-directed function invocation. Some of these transformation rules express the semantics of the subject domain; others represent more general programming techniques. The rules that introduce conditional expressions and recursive calls into the program are discussed in some detail.

The deductive techniques described are embedded in a running system called SYNSYS. This system accepts specifications expressed in high-level descriptive language and attempts to transform them into a corresponding LISP program. The transformation rules are expressed in the QLISP programming language. The synthesis of two programs performed by the system are presented.

This research was supported in part by the Advanced Research Projects Agency of the Department of Defense under Contract MDA903-76-C-0206, by the National Science Foundation under Grant DCR72-03737 A01, by the Office of Naval Research under Contracts N00014-76-C-0687 and N00014-75-C-0816; and by a grant from the United States-Israel Binational Science Foundation (BSF), Jerusalem, Israel.

The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of Stanford University, Stanford Research Institute, or the U.S. Government.
The incremental garbage collection of processes
Authors: Baker Henry C. , Hewitt Carl
Published: January 2007

This paper investigates some problems associated with an argument evaluation order that we call “future” order, which is different from both call-by-name and call-by-value, In call-by-future, each formal parameter of a function is bound to a separate process (called a “future”) dedicated to the evaluation of the corresponding argument. This mechanism allows the fully parallel evaluation of arguments to a function, and has been shown to augment the expressive power of a language.

We discuss an approach to a problem that arises in this context: futures which were thought to be relevant when they were created become irrelevant through being ignored in the body of the expression where they were bound. The problem of irrelevant processes also appears in multiprocessing problem-solving systems which start several processors working on the same problem but with different methods, and return with the solution which finishes first. This
parallel method
strategy has the drawback that the processes which are investigating the losing methods must be identified, stopped, and re-assigned to more useful tasks.
Language facilities for programmable backtracking
Authors: Griswold Ralph E. , Hanson David R.
Published: January 2007

Most languages intended for artificial intelligence applications include a search and backtracking facility. While built-in backtracking facilities are convenient, they are often too inflexible for use beyond a limited range of applicability. Other mechanisms, such as those based on explicit manipulations of bindings or stack frames, tend to be very unstructured, and give the programmer little control over the backtracking process. This paper describes the SL5 programming language and its use for “programmable backtracking.” SL5 includes a general procedure mechanism that permits procedures to be used as recursive functions or as coroutines. Using this mechanism, the programmer can construct control hierarchies that are tailored to the specific application. A string pattern-matching facility is given as an example of the use of the SL5 facilities.
Prolog - the language and its implementation compared with Lisp
Authors: Warren David H D , Pereira Luis M. , Pereira Fernando
Published: January 2007

Prolog is a simple but powerful programming language founded on symbolic logic. The basic computational mechanism is a pattern matching process (“unification”) operating on general record structures (“terms” of logic). We briefly review the language and compare it especially with pure Lisp. The remainder of the paper discusses techniques for implementing Prolog efficiently; in particular we describe how to compile the patterns involved in the matching process. These techniques are as incorporated in our DECsystem-10 Prolog compiler (written in Prolog). The code it generates is comparable in speed with that produced by existing DEC10 Lisp compilers. We argue that pattern matching is a better method for expressing operations on structured data than conventional selectors and constructors - both for the user and for the implementor.
A knowledge-based code generator generator
Authors: Fraser Christopher W.
Published: January 2007

XGEN is a program that accepts a machine description and produces a good local code generator for an ALGOL-like language. It is organized as a production system of rules codifying previously acquired human skills for dealing with computer architecture and programming languages.
Self-redefinition as a program manipulation strategy
Authors: Chatelin Philippe
Published: January 2007

This is an exploration of a constructive strategy for program improvement and synthesis. A first part recalls unfolding-folding style of manipulations initiated by BURSTALL and DARLINGTON with an application to proofs of equivalence of certain function compositions. Second part, in a more abstract way, presents three basic “forms” and their associated “transforms” constructed with this strategy in a hierarchical order ; they may serve as goals of transformations. Last part associates self-redefinition to mixed strategies for program composition: symbolic macro replacement, logarithmic speed up, resolution of formal recurrences. Each situation, where technique and method apply, is depicted on examples and open problems are evoked.
MobiCom poster
Authors: Antoine Stephane , Wei Ming , Aghvami A. H.
Published: January 2007

Mobile Internet protocol version 6 (MIPv6) [1] is a proposal for handling routing of IPv6 packets to mobile nodes that have moved away from their home network. We have studied the impact of the basic functionalities of MIPv6 on the performance of TCP when a mobile node (MN) moves between networks. The experiments carried involve a real internetwork connected to the experimental wide area IPv6 backbone and the mobile IPv6 software provided by "Kame" [2].
MobiCom poster
Authors: Chakraborty Dipanjan , Joshi Anupam
Published: January 2007

Development of customized services by discovering, integrating and executing existing ones (refered to as service composition) has received a lot of attention in the last few years with respect to wired, infrastrutcure based web-services. With the advancement in the wireless technology and pervasive computing, we envison that in the near future, we will have such information or services embedded in various wireless devices in our vicinity. However, wired infrastructure-based service discovery and composition architectures do not take into consideration factors arising from the possible mobility of the service providers. In this paper, we present Anamika: a distributed, de-centralized and fault-tolerant design architecture for distributed service discovery and reactive service composition in pervasive environments.
MobiCom poster
Authors: Lauer Michael , Matthes Michael
Published: January 2007

The ELAN-Project is an ongoing research focusing on an awareness based E-Learning infrastructure supporting collaborative work by the technical means of multi-hop ad-hoc networks.
Modeling, simulation and measurements of queuing delay under long-tail internet traffic
Authors: Garetto Michele , Towsley Don
Published: January 2007

In this paper we describe an analytical approach for estimating the queuing delay distribution on an Internet link carrying realistic TCP traffic, such as that produced by a large number of finite-size connections transferring files whose sizes are taken from a long-tail distribution. The analytical predictions are validated against detailed simulation experiments and real network measurements. Despite its simplicity, our model proves to be accurate and robust under a variety of operating conditions, and offers novel insights into the impact on the network of long-tail flow length distributions. Our contribution is a performance evaluation methodology that could be usefully employed in network dimensioning and engineering.
Modeling the throughput of TCP Vegas
Authors: Samios Charalampos (Babis) , Vernon Mary K.
Published: January 2007

Previous analytic models of TCP Vegas throughput have been developed for loss-free (all-Vegas) networks. This work develops a simple and accurate analytic model for the throughput of a TCP Vegas bulk transfer in the presence of packet loss, as a function of average round trip time, minimum round trip time, and loss rate for the transfer. Similar models have previously been developed for TCP Reno. However, several aspects of TCP Vegas need to be treated differently than their counterparts in Reno. The proposed model captures the key innovative mechanisms that Vegas employs during slow start, congestion avoidance, and congestion recovery. The results include (1) a simple, validated model of TCP Vegas throughput that can be used for equation-based rate control of other flows such as UDP streams, (2) a simple formula to determine, from the measured packet loss rate, whether the network buffers are overcommitted and thus the TCP Vegas flow cannot reach the specified target lower threshold on throughput, (3) new insights into the design and performance of TCP Vegas, and (4) comparisons between TCP Vegas and TCP Reno including new insights regarding incremental deployment of TCP Vegas.
Run-time modeling and estimation of operating system power consumption
Authors: Li Tao , John Lizy Kurian
Published: January 2007

The increasing constraints on power consumption in many computing systems point to the need for power modeling and estimation for all components of a system. The Operating System (OS) constitutes a major software component and dissipates a significant portion of total power in many modern application executions. Therefore, modeling OS power is imperative for accurate software power evaluation, as well as power management (e.g. dynamic thermal control and equal energy scheduling) in the light of OS-intensive workloads. This paper characterizes the power behavior of a commercial OS across a wide spectrum of applications to understand OS energy profiles and then proposes various models to cost-effectively estimate its run-time energy dissipation. The proposed models rely on a few simple parameters and have various degrees of complexity and accuracy. Experiments show that compared with cycle-accurate full-system simulation, the model can predict cumulative OS energy to within 1% accuracy for a set of benchmark programs evaluated on a high-end superscalar microprocessor. When applied to track run-time OS energy profiles, the proposed routine level OS power model offers superior accuracy than a simpler, flat OS power model, yielding per-routine estimation error of less than 6%. The most striking observation is the strong correlation between power consumption and the instructions per cycle (IPC) during OS routine executions. Since tools and methodology to measure IPC exist on modern microprocessors, the proposed models can estimate OS power for run-time dynamic thermal and energy management.
Effects of clock resolution on the scheduling of interactive and soft real-time processes
Authors: Etsion Yoav , Tsafrir Dan , Feitelson Dror G.
Published: January 2007

It is commonly agreed that scheduling mechanisms in general purpose operating systems do not provide adequate support for modern interactive applications, notably multimedia applications. The common solution to this problem is to devise specialized scheduling mechanisms that take the specific needs of such applications into account. A much simpler alternative is to better tune existing systems. In particular, we show that conventional scheduling algorithms typically only have little and possibly misleading information regarding the CPU usage of processes, because increasing CPU rates have caused the common 100 Hz clock interrupt rate to be coarser than most application time quanta. We therefore conduct an experimental analysis of what happens if this rate is significantly increased. Results indicate that much higher clock interrupt rates are possible with acceptable overheads, and lead to much better information. In addition we show that increasing the clock rate can provide a measure of support for soft real time requirements, even when using a general-purpose operating system. For example, we achieve a sub-millisecond latency under heavily loaded conditions.
Fairness and efficiency in web server protocols
Authors: Friedman Eric J. , Henderson Shane G.
Published: January 2007

We consider the problem of designing a preemptive protocol that is both fair and efficient when one is only concerned with the sojourn time of the job and not intermediate results. Our Fair Sojourn Protocol (FSP) is both efficient, in a strong sense (similar to the shortest remaining processing time protocol: SRPT), and fair, in the sense of guaranteeing that it weakly outperforms processor sharing (PS) for every job on any sample path.Our primary motivation is web serving in which the standard protocol is PS, while recent work proposes using SRPT or variants. Our work suggests both a framework in which to evaluate proposed protocols and an attractive new protocol, FSP.
Estimating membership in a multicast session
Authors: Alouf Sara , Altman Eitan , Barakat Chadi , Nain Philippe
Published: January 2007

We propose two novel on-line estimation algorithms to determine the size of a dynamic multicast group. We first use a Wiener filter to derive an optimal estimator for the membership size of the session in case the join process is Poisson and the lifetime of participants is distributed exponentially. We next develop the best first-order linear filter from which we derive an estimator that holds for any lifetime distribution. We apply this approach to the case where the lifetime distribution is hyperexponential. Both estimators hold under any traffic regime. Applying both estimators on real traces corresponding to video sessions, we find that both schemes behave well, one of which performs slightly better than the other in some cases. We further provide guidelines on how to tune the parameters involved in both schemes in order to achieve high quality estimation while simultaneously avoiding feedback implosion.
Active documents in XML
Authors: Bompani Luca , Ciancarini Paolo , Vitali Fabio
Published: January 2007

XML is an extremely promising approach to the standardization of most data structures, but the rendering semantics proposed with XSL is not sufficiently general, lacking support for arbitrary graphic objects and sophisticated notations.In this paper we introduce XMLC, a generic, modular XML browser that can display any kind of notation required for XML documents, and we also discuss the use of XMLC for active documents.
Retrieval operations and data representations in a context-addressed disc system
Authors: Su Stanley Y. W. , Copeland George P. , Lipovski G. Jack
Published: January 2007

This paper attempts to demonstrate that simple expansion of the processing capabilities of fixed disc read and write heads can avoid the multilevel mappings from high-level retrieval language to machine language and from user oriented data representation (information structure) to machine oriented data representation (storage structure) which are found necessary in conventional von Neumann computers. The processing capabilities built in the disc read and write heads for each disc track allow information files to be segmented and data items stored on all segments to be searched, modified, inserted, deleted, rearranged and rewritten simultaneously as a set of discs are rotating. Information structures such as the network structure, the hierarchical or tree structure and the relational structure are discussed and their implementations and basic search operations in the disc system are described.
Experimental simulation of an optical character recognition, speech output reading machine for the blind
Authors: Savoie Rob , Erickson Pat
Published: January 2007

This paper describes a project to investigate an Optical Character Recognition Speech-Output Reading Machine for the blind. A standard minicomputer accepts optical images derived from the electronic camera of an Optacon Reading Aid and converts these images to character streams representing letters of recognized words. A second computer then converts the letter strings to spoken words.The system operates in real-time at reading rates over 150 words per minute with the electronic camera moved either manually or automatically.
Using a computer message system for promoting reading and writing in a school for the deaf
Authors: Rubinstein Richard , Goldenberg E. Paul
Published: January 2007

Deaf children usually have great difficulty with English. A significant problem in teaching written English to the deaf is providing students with opportunities to use it for their own purposes: for communicating with friends or teachers. As soon as the hearing child learns to speak, English becomes a source of power and control. Deaf children miss this strong early motivation to learn English. We have been using a computer-based message system to provide written communication for students, teachers, and staff in a school for the deaf. Our initial experience suggests that this is an effective way to motivate deaf children to write. Further, it is providing a good research vehicle for studying the development of written language in deaf children.
Use of personal computing technology by deaf-blind individuals
Authors: Zuckerman Dan
Published: January 2007

This paper describes a system that enables deaf-blind people to work with micro-computers. This system utilizes the International Morse Code as a general communication medium. The deaf-blind person "hears" Morse Code via a vibrotactile device to "see" the computer's screen. This technique enables deaf-blind individuals to receive immediate feedback of their typing and scan the screen, thus making it possible for them to use the keyboard and screen in much the normal manner of seeing persons. A side benefit is that it provides a means for deaf-blind people to communicate with the sighted through a common medium: the sighted person can see the screen while the deaf-blind feels it. Hardware cost to equip a standard personal computer with this interface is negligible. Vibrotactile Morse Code is particularly viable because it can be adapted fro the individual's particular tactile sensitivities. Morse encoded tactile communication fits well in a social facilitation context for learning. It is technologically simple and standard. This work can significantly improve the quality of life for dear-blind individuals because it provides new opportunities for communication and vocation.