bluuebunny/crossref_metadata_2025 huggingface dataset:
Computational aspects of Hensel-type univariate polynomial greatest common divisor algorithms
Authors: Miola Alfonso , Yun David Y. Y.
Published: January 2007

Two Hensel-type univariate polynomial Greatest Common Divisor (GCD) algorithms are presented and compared. The regular linear Hensel construction is shown to be generally more efficient than the Zassenhaus quadratic construction. The UNIGCD algorithm for UNIvariate polynomial GCD computations, based on the regular Hensel construction is then presented and compared with the Modular algorithm based on the Chinese Remainder Algorithm. From both an analytical and an experimental point of view, the UNIGCD algorithm is shown to be preferable for many common univariate GCD computations. This is true even for dense polynomials, which was considered to be the most suitable case for the application of the Modular algorithm.
Presentation of the SCHOONSCHIP system
Authors: Strubbe H.
Published: January 2007

SCHOONSCHIP is the major algebra system in use at CERN. It was designed ten years ago by M. Veltman. It is set up to do long -- but in principle straightforward -- analytic calculations. It is very fast in execution and very economical in storage. It can easily deal with expressions of the size of 10
4
to 10
5
terms. This is achieved by writing it almost entirely in (CDC 6000/7000) machine code.
Experience with truncated power series
Authors: Gentleman W. Morven
Published: January 2007

The truncated power series package in ALTRAN has been available for over a year now, and it has proved itself to be a useful and exciting addition to the armoury of symbolic algebra. A wide variety of problems have been attacked with this tool: moreover, through use in the classroom, we have had the opportunity to observe how a large number of people react to the availability of this tool.
An interactive facility for symbolic mathematics
Authors: Blair F. W. , Griesmer J. H. , Jenks R. D.
Published: January 2007

This paper describes a system designed to provide an interactive symbolic computational facility for the mathematician user. To carry out this objective, an experimental LISP system has been implemented for IBM System/360 computers. Using this LISP system as a base, portions of several systems have been combined and augmented to provide the following facilities to a user:(1) rational function manipulation and simplification; symbolic differentiation (Anthony Hearn's REDUCE)(2) symbolic integration (Joel Moses' SIN)(3) polynomial factorization, solution of linear differential equations, direct and inverse symbolic Laplace transforms (Carl Engelman's MATHLAB, including Knut Korsvold's simplification system)(4) unlimited precision integer arithmetic(5) manipulation of arrays containing symbolic entries(6) two-dimensional output on IBM 2741 terminals or IBM 2250 displays (William Martin's Symbolic Mathematical Laboratory, and Jonathan Millen's CHARYBDIS program from MATHLAB)(7) self-extending language facility (META/LISP).The user language created for the system incorporates a subset of "customary" mathematical notation. Data objects include sequences (both finite and infinite) and arrays of arbitrary rank. Assignment statements are the fundamental commands in the user language; they may contain "for"-clauses which restrict the domain for which the assignment is valid and permit "piecewise" and recursive definition of new operators and functions. The user may also enter syntax definition statements in order to introduce new notations into the system.Expressions appearing in assignment statements may include "where"-clauses which allow user control over the "environment" used in evaluation. Otherwise, evaluation of expressions occurs in the current environment created by the successive user commands, with certain operations such as integration, differentiation, and simplification performed automatically.Translators for the user language and for a resident higher-level procedural language facility are written in META/LISP, a new self-compiling translator-writing system. As a result, all input language facilities as well as the underlying manipulation routines may be interactively extended by an experienced user.
Using minicomputers for algebraic computations
Authors: Cioni Gianna , Miola Alfonso
Published: January 2007

This paper deals with the use of minicomputers for doing algebraic computations.The current algebraic manipulation systems have generally unsuitable sizes for minicomputers. At present, the use of an algebraic system requires access to expensive computers that are often not immediately available. On the other hand, the success of minicomputers provides the very attractive possibility of bringing algebraic computation to more users than in the past. Actually, the work done checks this possibility having in mind, of course, particular types of applications.The main goal of our project has been to investigate whether or not it makes sense to use minicomputers in algebraic manipulation. Our conclusion is that for particular types of applications, it definitely does.
LISP/370
Authors: White Jon L
Published: January 2007

This description is written for the person having some experience with a LISP programming system, who wishes a brief description of some of the highlights of LISP/370. For details and more information, a
LISP/370 Program Description and Operations Manual
is available.
The SCRATCHPAD power series package
Authors: Norman Arthur C.
Published: January 2007

The power series package recently added to SCRATCHPAD differs in a number of important ways from the truncated power series facilities provided by various other algebra systems. This note is intended to highlight and attempt to justify some of these differences, and suggest how the existing system could be extended. A more formal description of the algorithms is in preparation.
Problem #9
Authors: Kahan W.
Published: January 2007

The problem concerns four variables a,b,c,d to be interpreted as centre (c,d) and principal semiaxes a,b of an ellipse [EQUATION] We wish to know when E lies inside the unit disk D: x
2
+ y
2
≤ 1. More precisely, we seek a set of polynomials {P
j
(a
2
, b
2
, c
2
, d
2
,)} for j=1,2,...,n with the property that E≤Dif and only if all P
j
(a
2
, b
2
, c
2
, d
2
,) ≤0. It is known that n> 1, but n should be minimal.
Automatic analysis of real algebraic curves
Authors: Arnon Dennis S.
Published: January 2007

We describe a computer program for the automatic analysis of a real plane affine algebraic curve. The input to the program is a bivariate integral polynomial
F
(
x, y
); the outputs are a report on the real curve defined by
F
(
x, y
) = 0, and a picture of the curve. The report contains the following information: whether the curve is irreducible, whether singular, and whether bounded; the number of its connected components and the dimension of each; the number of singular, turning, and level points of the curve. Approximations to these special points can be obtained to any desired precision; the more precision, the more time required. The exact form of the picture is controlled by the user; a topologically correct but "linearized" picture can be produced relatively quickly, while a more accurate drawing can be generated but requires more time. The program makes essential use of the clustering cylindrical algebraic decomposition algorithm [Arnon DS: Algorithms for the geometry of semi-algebraic sets (Dissertation). Technical Report #436, Computer Science Department, University of Wisconsin-Madison, 1981].
P-adic reconstruction of rational numbers
Authors: Wang Paul S. , Guy M. J. T. , Davenport J. H.
Published: January 2007

In a recent paper, Wang [1981] introduces a p-adic algorithm for the construction of partial fraction decompositions. This differs from the usual p-adic algorithms for factorisation or the computation of greatest common divisors ([Wang, 1978], [Wang, 1980], [Moore & Norman, 1981]) in that the p-adic image is used to reconstruct rational numbers, rather than integers.
SYPAC
Authors: di Scala R-M
Published: January 2007

The motivations for developping a computer algebra system based on Pascal and running on a micro-computer are manyfold. A first one is to develop an experimental system capable of manipulating infinite precision integers and integer polynomials in the persperctive of pedagogical use at high school level. A second one is to have a laboratory for implementing in Pascal some of the ideas developed a few years ago by Loos for ALDES (1, 2). A third one is to have an easely portable system; to achieve this goal we use a common subset of two different versions of Pascal: UCSD (University of California at San Diego) Pascal and Wirth's standard one. This subset will be called minimal Pascal. The choice of UCSD Pascal is due to its segmentation capability which makes the portability on different computers easier. Furthermore this Pascal is easely available on many machines.
The maple symbolic computation system
Authors: Char Bruce , Geddes Keith , Gonnet Gaston
Published: January 2007

The Maple system for algebraic computation is introduced. Samples of user/system interaction and of Maple programming are presented.
Problem section (rotating fluids)
Authors: Rimey Ken
Published: January 2007

A system of three third order polynomial equations with parameters is presented, along with its solution by the construction of a single carefully chosen determinant. This system displays some characteristics which may be common in practice, but are not dealt with effectively by most automatic solvers.
CAMP
Authors: Buchberger B.
Published: January 2007

After some years of preparatory experiments, in 1982 a curriculum has been installed at the University of Linz that gives graduate students of computer science and mathematics the possibility to specialize in the field of symbolic compuation (as an essential part of Computer-Aided Mathematical Problem Solving = CAMP). Students of computer science are supposed to have most of the necessary software / hardware / system background and are offered a series of courses on the formal / logical / mathematical / linguistic aspects of the field. Students of mathematics are supposed to catch up with the students of computer science with respect to the software / hardware / system aspects by forcing them to pass at least those courses of computer science that are an indispensible prerequisite for the field of symbolic computation. Then the students of mathematics are exposed to the series of courses on the formal / logical / mathematical / linguistic aspects of symbolic computation. The three main subareas of symbolic computation taught are: computer algebra, computational logic and automatic programming.
Self-explanatory symbolic computation for math education
Authors: Lichtenberger F.
Published: January 2007

In this position paper we will try to state some new ideas concerning the design of software systems for symbolic computation which are to be used in math education. Up to the late seventies computer algebra systems were running only on big mainframe computers. The muMATH-80 system was the first to be used on microcomputers running under the CP/M operating system. Since the first hand-held computers that can run CP/M are on the market, it seems obvious that in a few years we will have computer algebra systems on cheap hand-held or even pocket computers. The use of such computer algebra systems will probably have more influence on high school math than the appearence of electronic pocket calculators did have. If we now take a closer look at muMATH, one can see that most topics of mathematics that are relevant in high school, can de treated by the system. Some parts that had not been covered in the muMATH-80 version are covered by the muMATH-83 version, like for example vector algebra and simple differential equations. This shows the direction where things probably will go. Sooner or later all topics of high school math or even undergraduate math will be covered, at least in principle, by systems running on microcomputers. Further developments in the hardware field will accelerate this process, e.g. if the standard size for RAM storage in micros and hand-held computers increases from now 64 KB to, say, 256 KB.
Mining knowledge from text using information extraction
Authors: Mooney Raymond J. , Bunescu Razvan
Published: January 2007

An important approach to text mining involves the use of natural-language information extraction. Information extraction (IE) distills structured data or knowledge from unstructured text by identifying references to named entities as well as stated relationships between such entities. IE systems can be used to directly extricate abstract knowledge from a text corpus, or to extract concrete data from a set of documents which can then be further analyzed with traditional data-mining techniques to discover more general patterns. We discuss methods and implemented systems for both of these approaches and summarize results on mining real text corpora of biomedical abstracts, job announcements, and product descriptions. We also discuss challenges that arise when employing current information extraction technology to discover knowledge in text.
Using text mining and natural language processing for health care claims processing
Authors: Popowich Fred
Published: January 2007

A health care claims processing application is introduced which processes both structured and unstructured information associated with medical insurance claims. The application makes use of a natural language processing (NLP) engine, together with application-specific knowledge, written in a concept specification language. Using NLP techniques, the entities and relationships that act as indicators of recoverable claims are mined from management notes, call centre logs and patient records to identify medical claims that require further investigation. Text mining techniques can then be applied to find dependencies between different entities, and to combine indicators to provide scores to individual claims. Claims are scored to determine whether they involve potential fraud or abuse, or to determine whether claims should be paid by or in conjunction with other insurers or organizations. Dependencies between claims and other records can then be combined to create cases. Issues related to the design of the application are discussed, specifically the use of rule-based techniques which provide a capability for deeper analysis than traditionally found in statistical techniques.
Extracting statistical data frames from text
Authors: Liang Jisheng , Koperski Krzysztof , Nguyen Thien , Marchisio Giovanni
Published: January 2007

We present a framework that bridges the gap between natural language processing (NLP) and text mining. Central to this is a new approach to text parameterization that captures many interesting attributes of text usually ignored by standard indices, like the term-document matrix. By storing NLP tags, the new index supports a higher degree of knowledge discovery and pattern finding from text. The index is relatively compact, enabling dynamic search of arbitrary relationships and events in large document collections. We can export search results in formats and data structures that are transparent to statistical analysis tools like S-PLUSID®. In a number of experiments, we demonstrate how this framework can turn mountains of unstructured information into informative statistical graphs.
Symbolic mathematical computation
Authors: Griesmer James H.
Published: January 2007

The impact of high-speed computers on the scientific community over the past 25 years has been well documented. Their successful use for numerical computations in a number of areas of engineering and the sciences was followed by an interest in their being employed for 'literal' or symbolic computations. Problems in celestial mechanics, mathematics, and theoretical physics already pointed to the desirability of having such a capability. A number of systems for symbolic computation began to appear in the early 1960's. By 1965, sufficient interest in this area had developed to warrant the formation by the Association for Computing Machinery of the ACM Special Interest Group on Symbolic and Algebraic Manipulation (SIGSAM). During the next ten years, the field exhibited considerable growth as some of these early systems were revised, additional systems were introduced, and new symbolic capabilities were implemented. This has led to an ever-increasing use of symbolic computation on a wide variety of applications.
META/LISP
Authors: Jenks R. D.
Published: January 2007

META/LISP is a general purpose translator writing system for IBM System/360 currently running on TSS, CP/CMS, and OS/360. The input to the system is a source program which simultaneously describes 1) the syntax of some input data to be translated and 2) algorithms which operate on the input data and a pushdown stack to accomplish a desired translation; the output of the system is a compiled program for translating that input data. In particular when the input data are statements of a higher-level language to be translated into assembly language, META/LISP serves as a compiler-compiler. META/LISP uses the top-down syntax-directed approach which makes the system extremely attractive for the design and implementation of experimental languages; using META/LISP such compilers are easy to write, easy to check out, and - most importantly - easy to modify interactively. The appendices which follow a rather complete description of the system include a self-description of the META/LISP compiler.
Proactive context transfer and forced handover in IEEE 802.11 wireless LAN based access networks
Authors: Duong Ha , Dadej Arek , Gordon Steven
Published: January 2007

In recent years, many protocols have been developed to support user mobility in wireless networks, e.g. Mobile IP suite of protocols designed to support IP routing to mobile nodes. However, support for truly seamless mobility requires more than just routing: every service associated with the mobile user needs to be transferred smoothly to the new access network. In this paper, we will concentrate on the problem of transferring service state (context) at both the link and the IP layers. We propose a method to estimate the best moment in time for transferring context information associated with the mobile user. As one of key issues in the proactive context transfer scheme is accuracy of handover prediction, we suggest and describe a new concept of Forced Handover that can provide very low handover latency. The simulation results and the following discussions show that our scheme is helpful in ensuring seamless mobility, while keeping the number of unnecessary handovers resulting from the proactive nature of the scheme at a controllable level.
The entity-relationship model
Authors: Chen Peter Pin-Shan
Published: January 2007

A data model, called the entity-relationship model, is proposed. This model incorporates some of the important semantic information in the real world. A special diagramatic technique is introduced as a tool for data base design. An example of data base design and description using the model and the diagramatic technique is given. Some implications on data integrity, information retrieval, and data manipulation are discussed.The entity-relationship model can be used as a basis for unification of different views of data: the network model, the relational model, and the entity set model. Semantic ambiguities in these models are analyzed. Possible ways to derive their views of data from the entity-relationship model are presented.
Data base machines
Authors: Berra P. Bruce
Published: January 2007

In the past few years there has been increased emphasis in the use of new and different hardware in the data base management field. This has given rise to an interesting area of research called data base machines. The objectives are to implement many of the traditional software data base management functions in hardware in order to increase performance and capability.The reasons for increased research activity in data base machines are many fold. The modern digital computer with all its power still executes only a single instruction at a time al beit with a few exceptions. Since the digital computer was primarily designed for numeric applications, the ratio of useful instructions to overhead instructions tends to be very low in non-numeric applications such as data base management. There is an increasing body of knowledge that indicates that parallelism and addressing by content can be used to advantage in such data base management functions as retrieval and update. The above reasons coupled with the fact that software and personnel costs continued to rise while hardware costs continue to decrease makes it imperative that researchers find new solutions to the data base management problem that take maximum advantage of hardware architecture and technology.In this paper a brief review of current efforts in data base machines is presented. A review of the more important functions performed in data base management is given first. This is followed by a brief discussion of mini computer implementations. Then a review of some of the current efforts in data base machines is given. Finally, a few thoughts are presented on future trends.
The impact of personal computers on library-based information systems
Authors: Korfhage R. R.
Published: January 2007

With the size and price of computer hardware shrinking so rapidly, it is clear that we will shortly enter an era when computers are common both in the home and as portable personal tools. This wide availability of an information processing tool will impact the informational needs of each individual, and hence will impact any information service, including the news media, bookstores, and libraries.
WEIRD
Authors: Koll Matthew B.
Published: January 2007

WEIRD is an automatic document retrieval system designed and implemented at Syracuse University, which attempts to advance the art of computerized retrieval from word-matching to judging conceptual similarity. WEIRD uses a vector space model to represent the relations among terms and documents. Items in the space are located according to their "meaning", which is their proximity to all other items in the data base as measured by co-occurrence frequencies. This is done without manipulating large matrices. The dimensions of the space are not used to define relations; items are defined solely by their position relative to the other items. Retrieval is determined by Euclidean distance from the plotted query. In the first section of the paper the basic characteristics of WEIRD are described. Second, the results of a preliminary evaluation are reported. Alternatives for further development of WEIRD are then considered.
Sufficient conditions for flow admission control in wireless ad-hoc networks
Authors: Hamdaoui Bechir , Ramanathan Parameswaran
Published: January 2007

Wireless nodes within the same vicinity contend with each other for accessing the shared wireless medium. The contention constraints for sharing the medium depend on the medium access control (MAC) protocol that administers the accessibility of the network. In a previous work, we derived a set of sufficient conditions under which rates of all the flows are feasible given a MAC protocol. In this paper, we derive a new set of sufficient conditions that are better than those developed earlier. We show that these conditions are useful in solving many problems such as linear programming-based routing and admission control for QoS routing. We also evaluate, compare and discuss the performance of the derived sufficient conditions through simulation studies.
MANET simulation studies
Authors: Kurkowski Stuart , Camp Tracy , Colagrosso Michael
Published: January 2007

Simulation is the research tool of choice for a majority of the mobile ad hoc network (MANET) community. However, while the use of simulation has increased, the credibility of the simulation results has decreased. To determine the state of MANET simulation studies, we surveyed the 2000-2005 proceedings of the ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc). From our survey, we found significant shortfalls. We present the results of our survey in this paper. We then summarize common simulation study pitfalls found in our survey. Finally, we discuss the tools available that aid the development of rigorous simulation studies. We offer these results to the community with the hope of improving the credibility of MANET simulation-based studies.
SRDAG compaction
Authors: Linn Joseph L.
Published: January 2007

Microcode compaction is the process of converting essentially vertical microcode into horizontal microcode for a given architecture. The conventional plan calls for a microcode compiler to generate vertical code for a given architecture and then use a compaction system to produce horizontal code, thereby greatly reducing the complexity of horizontal code generation.This paper attempts to extend the existing techniques used to perform the compaction process. Specifically, the procedure presented generalizes the "trace scheduling" method of [Fisher81] by using more global context information in compaction decisions. A number of definitions from classical compaction are generalized to encompass this expanded scope.Further, the paper presents two example classes of problem for which the new method outperforms the trace scheduling technique in terms of the execution time efficiency of the generated code. A number of unresolved questions are noted involving the class of global compaction procedures.
Tree compaction of microprograms
Authors: Lah Jehkwan , Atkins Daniel E.
Published: January 2007

Although Fisher's
trace scheduling
procedure for global compaction may produce significant reduction in execution time of compacted microcode, the growth of memory size by extensive copying of blocks can be enormous. In the worst case, the memory size can grow exponentially [FIS81a] and the complex bookkeeping stage of the trace scheduling is an obstacle to implementation.A technique called
tree compaction
, which is based on the trace scheduling, is proposed to mitigate these drawbacks. Basically, it partitions a given set of microprogram blocks into tree-shaped subsets and applies the idea of trace scheduling on each tree-shaped subset separately. It achieves almost all of the compaction of the Fisher's trace scheduling procedure except that which causes copying of blocks. Preliminary tests indicate that tree compaction gives almost as short execution time as trace scheduling but with much less memory. The paper includes such an example.
An E-Machine workbench
Authors: Wagnon Gylver , Maine Dennis J. W.
Published: January 2007

The development environment for microprogramming an implementation (E-Machine) of the Burroughs stack architecture (E-Mode) is discussed with an overview of a supporting hardware organization (the Alpha machine). The set of information-sharing tools in the E-Machine workbench, especially the structured language Ohne, is described and a sample E-Mode operator is used to illustrate several of these tools.
Identification of microprogrammable loops for problem oriented architecture synthesis
Authors: Shin H. , Malek M.
Published: January 2007

The performance of a microprogrammable computer with the writable control memory can be improved by embedding a loop as a single microprogrammed instruction. This paper presents an algorithm for the identification of microprogrammable loops based on the construction of an interval. Also, implementation strategies are discussed with respect to such implementation phases as synthesis of a new instruction and its loading into the control memory. Finally, from the performance point of view, the problem oriented architecture synthesis is compared with the CPU operation overlap.
Flow graph machine models in microcode synthesis
Authors: Mueller Robert A. , Varghese Joseph
Published: January 2007

Retargetability of microcode compilers is currently a major issue in microprogramming. We address the issue of local code generation from machine-independent specifications using weakest precondition semantics. The micromachine model used is a flow graph which is an abstract representation of the data paths of the machine. Examples of code generated by a prototype implementation are provided as an illustration of the method.
Experience developing microcode using a high level language
Authors: Gurd R. Preston
Published: January 2007

This paper describes a project in which every line of microcode developed was written in a high level language.
High level microprogramming
Authors: Davidson Scott
Published: January 2007

High level microprogramming languages have been studied extensively, but no widely accepted HLML exists to date. We examine the classes of HLMLs, giving examples. We then give some reasons as to the current lack of an accepted HLML, and give some suggestions how to solve this problem. The existence of a HLML would allow work on higher level microprogramming and firware engineering to proceed more rapidly. A possible microprogramming environment, based on a HLML, is presented.
Mailnet
Authors: Heller Paul
Published: January 2007

During the past year there has been rapid growth in the use of computer-based electronic mail systems. Electronic mail is used for communication among colleagues on a given campus and, more recently, among peers on different campuses. Campus-based electronic mail systems have proven convenient and effective for local users. Distant users find such systems useful but relatively expensive and inconvenient. The Mailnet service currently being developed by EDUNET and EDUCOM will provide a means for electronic mail communication with distant colleagues by linking numerous local systems together. Each user will have the convenience and low cost of a local system even when communicating with persons elsewhere in the world. Operators of local (e.g., campus) mail systems will be able to connect to Mailnet without having to acquire any new equipment or to modify existing equipment or operating systems.
An optimization problem in adaptive virtual environments
Authors: Sundararaj Ananth I. , Sanghi Manan , Lange John R. , Dinda Peter A.
Published: January 2007

A virtual execution environment consisting of virtual machines (VMs) interconnected with virtual networks provides opportunities to dynamically optimize, at run-time, the performance of existing,
unmodified
distributed applications without any user or programmer intervention. Along with resource monitoring and inference and application-independent adaptation mechanisms, efficient adaptation algorithms are key to the success of such an effort. In previous work we have described our measurement and inference framework, explained our adaptation mechanisms, and proposed simple heuristics as adaptation algorithms. Though we were successful in improving performance as compared to the case with no adaptation, none of our algorithms were characterized by theoretically proven bounds. In this paper, we formalize the adaptation problem, show that it is NP-hard and propose research directions for coming up with an efficient solution.
On unreliable computing systems when heavy-tails appear as a result of the recovery procedure
Authors: Fiorini Pierre M. , Sheahan Robert , Lipsky Lester
Published: January 2007

For some computing systems, failure is rare enough that it can be ignored. In other systems, failure is so common that how to handle it can have a significant impact on the performance of the system. There are many different recovery schemes for tasks, however, they can be classified into three broad categories: 1)
Resume:
when a task fails, it knows exactly where it stops and can continue at that point when allowed to resume (i.e.,
preemptive resume - prs);
2)
Replace
: when a task fails, then later when the processor continues, it begins with a brand new task (i.e.,
preemptive repeat different prd);
and, 3)
Restart:
when a task fails it loses all work done to that point and must start anew upon continuing later (i.e.,
preemptive repeat identical - pri
).In this paper, assuming a computing system is unreliable, we discuss how
heavy-tail
(hereafter referred to as
power-tail
- PT) distributions can appear in a job's task stream given the
Restart
recovery procedure. This is an important consideration since it is known that power-tails can lead to unstable systems [4], We then demonstrate how to obtain performance and dependablity measures for a class of computing systems comprised of
P
unreliable processors and a finite number of tasks
N
given the above recovery procedures.
Constructs for the specifications of models and experimental frames
Authors: Zeigler Bernard P.
Published: January 2007

There is increasing recognition that simulation modelling of multifaceted systems cannot be accomplished successfully within the framework of a "oneshot" finite lifetime simulation project but must rather be viewed as an ongoing activity supported by the appropriate computational facilities [1]. The latter view requires the development of advanced modelling concepts [2], and the theory on which to base them [3]. Such developments should be coordinated with the software engineering design of integrated modelling systems to implement such advanced concepts [4,5].
Combined continuous/discrete system simulation languages
Authors: Cellier Francois E.
Published: January 2007

The term "combined simulation" is not sufficiently well understood in the literature yet to mean one and only one specific methodology or problem class. One can find references where e.g., combined simulation is used as synonym for hybrid simulation. This term, therefore, requires some definition first to clarify how it is going to be used in this context - especially since the author tends to use it in a slightly different way than most people do.
Xaviera's establishment
Authors: Solomon Susan L.
Published: January 2007

Xaviera operates an entertainment facility in Nevada. In order to preserve her share of the market, she wishes to examine the level of service offered to her customers under the following alternative conditions.
Another approach to a GPSS final examination
Authors: Highland Harold Joseph
Published: January 2007

Preparing a final examination in a modeling and simulation course is always a problem for me since I am never satisfied with the results. I am not certain if the students 'memorized' different terms and procedures or have a realistic view of the subject. Last year, I faced the same problem when teaching a fourth year-graduate course in conceptual modeling for the Computer Science Department at Hofstra University.
Simulation of blood bank systems
Authors: Cohen Morris A. , Pierskalla William P.
Published: January 2007

This paper examines the use of simulations to develop decision procedures for the management of individual hospital blood banks and central blood bank systems. Due to the perishability of blood products and the stochastic nature of both the demand and supply processes, such multi-product, multiechelon systems can only be analyzed effectively by simulation. The hospital and central bank model structures are reviewed, as are the input, output, and validation analysis procedures. A number of issues relevant to the application of simulation to health care systems analysis are raised by the development and application of these models. Of particular interest is the integration of the simulations into a recursive statistics-optimization-simulation approach to systems analysis.
Simulation in surgery, anesthesia and medical interviewing
Authors: Esogbue Augustine O.
Published: January 2007

In this paper, we present a bird's-eye view of our work in health systems involving the applications of simulation to the surgical department, anesthesia, and medical diagnosis. Through all these models, an attempt is made to provide the reader with appropriate insights into the process of problem selection, language choice, analysis, interpretation and implementation of results, as well as the limitations of simulation in health systems.
An elevator problem
Authors: Schriber Thomas J.
Published: January 2007

The elevator problem was composed by the Problem Corner editor for use in an introductory simulation course offered regularly at The University of Michigan. What appears here is an exact copy of the problem statement as handed out to the students. Hence, interested SIMULETTER readers who teach simulation might be able to use this problem statement, without modification, in their teaching. The problem was designed for GPSS implementation [it is appropriate for students who have finished the first five chapters in Simulation Using GPSS (Wiley & Sons, 1974)], but of course can also be modeled in GASP, or SIMSCRIPT, or SIMULA, etc.
Monitoring link delays with one measurement host
Authors: Burch Hal , Chase Chris
Published: January 2007

We present RCM, a system to monitor link delays on a network using a single measurement host. RCM is a combination of a new measurement system and a new network tomography technique. The measurement system employs tunnels to connect to border routers where it can source and sink measurements across the network. RCM uses network tomography to calculate the delays across individual network links from these measurements. The network tomography technique expands on previous linear algebra techniques to deal with the limitations of the resulting data without assuming either link delay symmetry or a particular topology. The network tomographic technique is compared against direct measurements in simulation to ensure accuracy. RCM is deployed on a large ISP's network to diagnose the cause of end-to-end delays, from which additional results are presented. The results are compared against known behaviors of the network to ensure the results are consistent with those behaviors. The system is analyzed for its ability to pin-point the cause of changes in end-to-end delay.
Observations on Cisco sampled NetFlow
Authors: Choi Baek-Young , Bhattacharyya Supratik
Published: January 2007

Traffic monitoring is an important first step for network management and traffic engineering. With high-speed Internet backbone links, efficient and effective packet sampling is not only desirable, but also increasingly becoming a necessity. The Sampled NetFlow [10] is Cisco router's traffic measurement functionality with static packet sampling for high speed links. Since the utility of sampling depends on the
accuracy
and
economy
of measurement, it is important to understand sampling error and measurement overhead. In this paper, we first discuss fundamental limitations of sampling techniques used in the Sampled NetFlow. We assess the accuracy of the Sampled NetFlow by comparing its output with complete packet traces [8] from an operational router. We also show the overheads involved in the Sampled NetFlow. We find that Sampled NetFlow performs correctly without incurring dramatic overhead during our experiments. However, a care should be taken in its use, since the overhead is linearly proportional to the number of flow records.
SIGIR workshop report
Authors: Baraglia Ranieri , Laforenza Domenico , Silvestri Fabrizio
Published: January 2007

In the last few years there have been the explosion in the use of heterogeneous distributed systems. Ranging from simple Network of Workstations to the more modern and complex Grid systems, the adoption of distributed systems instead of massively parallel supercomputers has been preferred due to their reduced cost of ownership. These kinds of systems pose many challenges in terms of information access, storage and retrieval. Usually, in fact, instead of having collections stored at a single site they are collected, and sometimes managed, at different sites (possibly owned by different institutions). Particular interest has been expressed on architectures and specifications for information retrieval in the context of heterogeneous distributed computing systems.
On using a hardware monitor as an intelligent peripheral
Authors: Hughes James , Cronshaw David
Published: January 2007

Conventionally, hardware monitoring has been performed using manually controlled off-line devices.It is suggested that a hardware monitor incorporating program control and acting as an intelligent peripheral device would realize greater utility and wider application. The development and application of such a device is described; a combination of the merits of both software and hardware monitoring techniques is claimed for it.
Prediction and ranking algorithms for event-based network data
Authors: O'Madadhain Joshua , Hutchins Jon , Smyth Padhraic
Published: January 2007

Event-based network data consists of sets of events over time, each of which may involve multiple entities. Examples include email traffic, telephone calls, and research publications (interpreted as co-authorship events). Traditional network analysis techniques, such as social network models, often aggregate the relational information from each event into a single static network. In contrast, in this paper we focus on the temporal nature of such data. In particular, we look at the problems of temporal link prediction and node ranking, and describe new methods that illustrate opportunities for data mining and machine learning techniques in this context. Experimental results are discussed for a large set of co-authorship events measured over multiple years, and a large corporate email data set spanning 21 months.
Relevance search and anomaly detection in bipartite graphs
Authors: Sun Jimeng , Qu Huiming , Chakrabarti Deepayan , Faloutsos Christos
Published: January 2007

Many real applications can be modeled using bipartite graphs, such as users vs. files in a P2P system, traders vs. stocks in a financial trading system, conferences vs. authors in a scientific publication network, and so on. We introduce two operations on bipartite graphs: 1) identifying similar nodes (relevance search), and 2) finding nodes connecting irrelevant nodes (anomaly detection). And we propose algorithms to compute the relevance score for each node using random walk with restarts and graph partitioning; we also propose algorithms to identify anomalies, using relevance scores. We evaluate the quality of relevance search based on semantics of the datasets, and we also measure the performance of the anomaly detection algorithm with manually injected anomalies. Both effectiveness and efficiency of the methods are confirmed by experiments on several real datasets.
Link mining applications
Authors: Senator Ted E.
Published: January 2007

This article reviews a decade of progress in the area of link mining, focusing on application requirements and how they have and have not yet been addressed, especially in the area of complex event detection. It discusses some ongoing challenges and suggests ideas that could be opportunities for solutions. The most important conclusion of this article is that while there are many link mining techniques that work well for individual link mining tasks, there is not yet a comprehensive framework that can support a combination of link mining tasks as needed for many real applications.
Data mining methods for anomaly detection KDD-2005 workshop report
Authors: Margineantu Dragos , Bay Stephen , Chan Philip , Lane Terran
Published: January 2007

For many applications, data mining systems are required to detect anomalous (abnormal, unmodeled, or unexpected) observations. This has so far proven to be a difficult challenge because anomalies are usually considered to be "non-normal" observations, where "normality" is typically defined by very complex concepts. Because of these and other reasons, there are no standard and principled approaches for anomaly detection, yet, and the data mining processes that have led to successful solutions include most of the times ad-hoc (algorithmic, design, and implementation) decisions that incorporate prior or commonsense knowledge about the tasks that are addressed.Consequently, we considered that it would be beneficial for both researchers and practitioners interested in anomaly detection and data mining, to organize workshop that would bring together people interested in this topic. We considered that the International Conference on Knowledge Discovery and Data Mining would be a good venue for such a workshop because of the diversity of interests, backgrounds, and problems that motivate people to attend the conference.This paper describes the workshop on "Data Mining Methods for Anomaly Detection" - a one day event held in conjunction with KDD-2005 in Chicago, on August 21, 2005.
Certifying authenticity via fiber-infused paper
Authors: Chen Yuqun , Mihçak M. Kivanç , Kirovski Darko
Published: January 2007

A certificate of authenticity (COA) is an inexpensive physical object that has a random unique structure with high cost of near-exact reproduction. An additional requirement is that the uniqueness of COA's random structure can be verified using an inexpensive device. Bauder was the first to propose COAs created as a randomized augmentation of a set of fibers into a transparent gluing material that randomly fixes once for all the position of the fibers within. In this paper, we propose a novel system for automated verification of fiber-based COAs and outline the key challenges in enabling high cost-efficiency of such a system. The key features of the new COA scanner are simplicity, reliability, lack of any moving components, and the ability to accurately identify exact positions of individual fibers infused in COA's containing paper. The latter feature significantly increases the forging cost compared to trivial implementations of a COA scanner.
PackaTAC
Authors: Dahlgren Erik , Wurman Peter R.
Published: January 2007

The Supply Chain Management game presents a challenging manufacturing scenario where agents compete for customer demand and supplies needed to produce the demanded products. The entry of North Carolina State University, PackaTAC, is a relatively simple agent that plays a conservative, low-risk strategy. Its aim is to never bid on more orders than it can handle, while maintaining low inventory levels and aspiring to full factory utilization. The agent relies on the fact that it will have ten opportunities to win contracts for a given production day, and constantly adjusts its profit margins to track the market prices. Its low risk approach was chosen to combat the mutually destructive strategies that were emerging during the qualifying rounds. Despite PackaTAC's simple approach, it performed quite well in the 2003 competition held at the International Joint Conference on Artificial Intelligence in Acapulco.