bluuebunny/crossref_metadata_2025 huggingface dataset:
ELECTRICAL AND MAGNETIC PROPERTIES IN Bi:2223 BULK DOPED WITH Cr
Authors: ILONCA G. , POP A. V. , DEAC I. G. , JURCUT T. , REDAC R. , DULAMITA N. , DELTOUR R.
Published: July 2002

High-T c cuprates of "Bi-2223" bulk doped with Cr 0≤ x≤ 0.10 were prepared by the conventional solid state reaction method. The samples were investigated by electrical resistivity, Hall effect, Nernst effect, ac susceptibility and thermopower measurements in mixed and normal states. The transport coefficients depend strongly on the Cr contents in the samples. The temperature dependence nH(T) and inverse Hall mobility [Formula: see text] show an anomaly at a temperature around 240 K. These anomalies are discussed in the framework of phase separation theory. The experimental data in the mixed state are in agreement with the predictions of the time-dependent Ginsburg–Landau theory.
FIRST-ORDER TRANSITION IN A SPIN MODEL FOR SELF-ORGANIZATION
Authors: BAUVIN R. , KAMP Y.
Published: July 2002

The paper examines the emergence of self-organization in a population where tandem recruitment is combined with individual memory. The time evolution is modeled as a two-dimensional spin system with local interaction along the time axis and a mean-field interaction along the other axis. We generalize a previous result obtained with this model from the case of two sources to the multisource situation and show a twofold connection with the Potts model. First, when individual memory exceeds a critical value, a phase transition sets in, which is second order for two sources but first order beyond, similarly to the mean-field theory of the Potts model. In addition, the self-organization problem considered here relies on a special case of the one-dimensional nearest-neighbor Potts model with external field, which is shown to be explicitly solvable.
CHATTER, STICKING AND CHAOTIC IMPACTING MOTION IN A TWO-DEGREE OF FREEDOM IMPACT OSCILLATOR
Authors: WAGG D. J. , BISHOP S. R.
Published: July 2002

We consider the dynamics of a two-degree of freedom impact oscillator subject to a motion limiting constraint. These systems exhibit a range of periodic and nonperiodic impact motions. For a particular set of parameters, we consider the bifurcations which occur between differing regimes of impacting motion and in particular those which occur due to a grazing bifurcation. Unexpected resonant behavior is also observed, due to the complexity of the dynamics. We consider both periodic and chaotic chatter motions and the regions of sticking which exist. Finally we consider the types of chaotic motion that occur within the parameter range. We discuss the possibility in relating successive low velocity impacts, especially with respect to possible low dimensional mappings for such a system.
LINEAR CONTROL IN A LATTICE OF COUPLED SECOND-ORDER OSCILLATORS
Authors: ALVAREZ-RAMIREZ JOSE , PUEBLA HECTOR , ESPINOSA GILBERTO
Published: July 2002

This paper presents a decentralized linear feedback control for a lattice of coupled second-order systems with external forces. A classical linear PID control is used at each local site. A sufficient condition to obtain nonlocal results on stabilization and synchronization is provided. This condition does not depend on the system size neither on the coupling structure; hence, it allows us to obtain a systematic procedure for analyzing feedback control of coupled oscillators. Some implications of our results on locomotory motion control are discussed. Numerical examples are used to illustrate the theoretical results.
PHASE INSTABILITIES OF DISTORTED HEXAGONAL PATTERNS
Authors: PEÑA B. , PÉREZ–GARCÍA C.
Published: July 2002

We present an analytical study on the stability of distorted hexagonal patterns. From a general amplitude equation we calculate the instabilities with respect to homogeneous and longwave perturbations. The latter lead to the phase equations that permit to determine the stability regions. Slightly squeezed hexagons are locally stable in a full range of distortion angles. The stability regions obtained from the phase equation are similar to those obtained numerically by other authors [Gunaratne et al., 1994].
A PROBABILISTIC SYMMETRIC ENCRYPTION SCHEME FOR VERY FAST SECURE COMMUNICATION BASED ON CHAOTIC SYSTEMS OF DIFFERENCE EQUATIONS
Authors: PAPADIMITRIOU S. , BOUNTIS T. , MAVROUDI S. , BEZERIANOS A.
Published: July 2002

We present a new probabilistic symmetric key encryption scheme based on the chaotic dynamics of properly designed chaotic systems. This technique exploits the concept of virtual attractors, which are not real attractors of the underlying chaotic dynamics but are created and maintained artificially. Each virtual attractor represents a symbol of the alphabet used to encode messages. The state space is partitioned over the virtual attractors creating clusters of states. The enciphering process randomizes over the set of states mapped to a virtual attractor in order to construct the ciphertext for the transmited symbol. The receiver can reconstruct perfectly this virtual state space, given the possession of the same chaotic system of difference equations with parameters tuned perfectly to those of the transmitter. Therefore, from the ciphertext chunk corresponding to a state, the virtual attractor can be derived from the details of the virtual state space. The knowledge of the virtual attractor leads to the recovery of the transmitted symbol.

We demonstrate that the new algorithm is secure, reliable and very fast. It uses discrete time chaotic recurrent systems and is simple, flexible and modular. These systems can be constructed easily dynamically from an alphanumeric encryption key. The cryptographic security of the algorithm is evaluated with combinatorial arguments.
A FRACTIONAL BROWNIAN MOTION MODEL FOR TIME SERIES PRODUCED BY CONSTANT TEMPERATURE MOLECULAR DYNAMICS SIMULATIONS
Authors: KARAKASIDIS THEODOROS E. , ANDREADIS IOANNIS
Published: July 2002

In the present work we performed an analysis of time series of instantaneous temperature and pressure produced during constant temperature molecular dynamics. Simulations were applied to a nickel oxide grain boundary for a temperature range 0.15-0.80Tm, Tm being the melting point of the system. We performed a series of analysis for these time series including test for randomness, power spectrum, Hurst exponent and structure function test. Evidence of fractional Brownian motion was found. Pressure presents 1/f over the whole range of frequencies of the system while temperature presents a two-regime behavior: white noise at low frequencies and 1/fα at high frequencies with α increasing as a function of temperature. The origins of this behavior are discussed.
CONTROLLING SYSTEMS WITH IMPACTS
Authors: AWREJCEWICZ J. , TOMCZAK K. , LAMARQUE C.-H.
Published: July 2002

The method of controlling and improvement of stability of periodic orbits of vibro-impact systems is proposed. This method is based on the feedback loop control with a time delay.
REPRESENTATIVE BRAIDS FOR LINKS ASSOCIATED TO PLANE IMMERSED CURVES
Authors: COUTURE O. , PERRON B.
Published: July 2002

In [ AC 2], A'Campo associates a link in S3 to any proper generic immersion of a disjoint union of arcs into a 2-disc. We give a sample algorithmic way to produce, from the immersion, a representative braid for such links. As a by-product we get a minimal representative braid for any algebraic link, from a divide associated to a real deformation of the polynomial defining the link.
VIRTUAL ARC PRESENTATIONS AND HC-MOVES OF RIBBON 2-KNOTS
Authors: KANENOBU TAIZO
Published: July 2002

The HC-move was defined as an unknotting operation of a ribbon 2-knot. Representing a ribbon 2-knot by a virtual arc, we see that the HC-move corresponds to one of the "forbidden moves", which unknot every virtual knot. Using this, we consider the α2-invariant of a ribbon 2-knot and a relation between the Δ-move for a 1-knot and the HC-move for its spun 2-knot.
PERFECT FLUID COSMOLOGIES WITH VARYING LIGHT SPEED
Authors: CHIMENTO LUIS P. , JAKUBI ALEJANDRO S.
Published: July 2002

We have found exact constant solutions for the cosmological density parameter using a generalization of general relativity that incorporates a cosmic time-variation of the velocity of light in vacuum and the Newtonian gravitation constant. We have determined the conditions when these solutions are attractors for an expanding universe and solved the problems of the Standard Big Bang model for perfect fluids.
TIDAL FORCES IN COLD BLACK HOLE SPACETIMES
Authors: NANDI K. K. , NAYAK T. B. , BHADRA A. , ALSING P. M.
Published: July 2002

We investigate here the behavior of a few spherically symmetric static acclaimed black hole solutions in respect of tidal forces in the geodesic frame. It turns out that the forces diverge on the horizon of cold black holes (CBH) while for ordinary ones, they do not. It is pointed out that Kruskal-like extensions do not render the CBH metrics nonsingular. We present a CBH that is available in the Brans–Dicke theory for which the tidal forces do not diverge on the horizon and in that sense it is a better one.
ANISOTROPIC FLUIDS IN THE CASE OF STATIONARY AND AXISYMMETRIC SPACES OF GENERAL RELATIVITY
Authors: PAPAKOSTAS T.
Published: July 2002

We present a stationary axisymmetric solution belonging to Carter's family [Ã] of spaces and representing an anisotropic fluid configuration
GRAVITOMAGNETISM AND THE BERRY PHASE OF PHOTON IN AN ROTATING GRAVITATIONAL FIELD
Authors: FENG LONG-LONG , LEE WOLUNG
Published: July 2002

In this paper, we present an investigation of the Berry phase that a photon acquired during its propagating through a gravitational field produced by a Kerr black hole. Starting from the Maxwell equation in Kerr–Schild metric form of Kerr black hole, we give the zeroth order Hamiltonian of the photon under geometric optics approximation. The helicity state of the photon is then derived. We demonstrate that there are two factors leading to the Berry phase that the photon acquires in a gravitational field. These are the adiabatic transport of the local comoving tetrad and the rotation of the equivalent magnetic field that we introduce. The straightforward calculation show that the appearance of Berry phase is attributed to the twisted optical path due to the rotation of black hole. It is in fact analogous to the observed optical rotation for a linear polarized light propagating in an helical optical fiber.
PROBES OF THE VACUUM STRUCTURE OF QUANTUM FIELDS IN CLASSICAL BACKGROUNDS
Authors: SRIRAMKUMAR L. , PADMANABHAN T.
Published: July 2002

We compare the different approaches presently available in literature to probe the vacuum structure of quantum fields in classical electromagnetic and gravitational backgrounds. We compare the results from the Bogolubov transformations and the effective Lagrangian approach with the response of monopole detectors (of the Unruh–DeWitt type) in noninertial frames in flat spacetime and in inertial frames in different types of classical electromagnetic backgrounds. We also carry out such a comparison in inertial and rotating frames when boundaries are present in flat spacetime. We find that the results from these different approaches do not, in general, agree with each other. We attempt to identify the origin of these differences and then go on to discuss its implications for classical gravitational backgrounds.
PROBABILISTIC DETERMINATION OF STABILITY FOR A DELAY-DIFFERENTIAL MODEL OF THE GLUCOSE-INSULIN DYNAMICAL SYSTEM
Authors: DE GAETANO A. , ARINO O.
Published: July 2002

Some of the questions involved in the formulation of a new model for a physiological phenomenon, when the model represents a dynamical system, concern its qualitative behavior. The determination of the stability of a particular dynamical system is usually made analytically, from a linearization of the system around an equilibrium point. This analytic proof may often be complicated or impossible, leading to the imposition of conditions on the relative magnitude of the model structural parameters or to other partial results. We discuss a general technique whereby a probabilistic judgement is made on the stability of a dynamical system, and we apply it to the study of a particular delay differential system modelling the relationship between insulin secretion and glucose uptake. This technique is applicable in case experimental material is available: a stability criterion is obtained via the usual linearization around an equilibrium point and its distribution is approximated from the estimated dispersion of the model parameters. The probability that the stability criterion is such as to make the model stable can then be computed directly. While the conclusion is probabilistic in nature, it is generally applicable to a vast class of models.
FREE MICROSURGICAL TOE PULP FLAP
Authors: Foucher G. , Pajardi G.
Published: July 2002

The pulp of the toe provides a unique source to cover the fingertips with the same texture and mechanical receptors. Free microsurgical transfer is technically possible. Sensory reeducation can improve the discrimination of the donor site. We reviewed with a 7-year follow-up of 44 patients having a simple or composite toe pulp transfer. Mean age of the population was 22 years. 2PD was an average of 12 mm and Semmes Weinstein was 4.31 in 80% of cases. The result was not influenced by age, smoking habit, dominance, ray reconstructed or ischaemia time. Of significance was the number of arteries feeding the transfer, job activity and type of trauma.
ARTHROSCOPIC WAFER PROCEDURE
Authors: Imaeda Toshihiko , Nakamura Ryogo , Tsunoda Kenji , Watanabe Kentaro
Published: July 2002

Thirteen of 15 patients with ulnocarpal abutment syndrome who underwent an arthroscopic wafer procedure since 1991 were seen in follow-up at least six months postoperatively. An arthroscopic wafer procedure was performed during which the triangular fibrocartilage complex (TFCC) was partially removed with a blade and a basket punch was made through the 4–5 arthroscopic portal. The ulnar head was then partially removed with a motorized burr through the 4–5 or 6R portal. The modified Mayo wrist score was used to evaluate the results. Four wrists produced excellent results; six wrists, good; two wrists, fair; and one wrist, poor. The wrists with a null or negative ulnar variance after the procedure achieved a better result than those with a remaining positive ulnar variance at the most prominent as well as at the deepest level of the resected ulna. The arthroscopic wafer procedure offers the benefits of a minimally invasive procedure; however, it is technically demanding to remove the ulnar head with a negative ulnar variance at the most prominent level as well as at the deepest level of the resected ulnar head.
THE SAUVÉ-KAPANDJI PROCEDURE IN COMBINATION WITH OPENING RADIAL WEDGE OSTEOTOMY FOR MALUNION OF DISTAL RADIUS FRACTURES
Authors: Hattori Yasunori , Doi Kazuteru , Kuwata Noriyuki , Kawakami Fujio , Ohtuka Ken
Published: July 2002

The Sauvé-Kapandji procedure in combination with an opening radial wedge osteotomy for malunion of distal radius fractures was performed in six patients. Follow-up at an average of 40.3 months showed two excellent, three good, and one poor result. Satisfactory results were obtained in restoration of forearm rotation and improvement of pain in all patients. The Sauvé-Kapandji procedure in addition to an opening radial wedge osteotomy was indicated when a preoperative limitation of forearm rotation with severe pain and radiographic evidence of degenerative changes in the distal radioulnar joint were present. We have found combining these two procedures to be a reliable treatment option for malunion of distal radius fractures.
ARBITRATION PROTOCOLS FOR COMPETING SOFTWARE AGENTS
Authors: TESCH THOMAS , FANKHAUSER PETER , OUKSEL ARIS M.
Published: July 2002

The exchange of goods and services between bargaining software agents requires new forms of brokering mechanisms which achieve consensus between conflicting parties. Such mechanisms have to be designed in a way that they give rational self-interested agents no incentives for insincere behavior. We introduce an arbiter as third party that resolves conflicting bargaining situations between the agents. To achieve non-manipulative agent behavior, we investigate three arbitration protocols that avoid different forms of manipulations and show how each trades net efficiency for robustness against manipulations. We describe the applicability of the protocols in bilateral bargaining situations and, analyze their robustness against manipulations analytically and by simulations. We compare the protocols with Nash's arbitration1 and the Groves-Clarke tax2 and characterize situations in which our protocols are superior.
ON THE SYMMETRY AND UNIQUENESS OF SOLUTIONS OF THE GINZBURG–LANDAU EQUATIONS FOR SMALL DOMAINS
Authors: AFTALION A. , DANCER E. N.
Published: July 2002

In this paper, we study the Ginzburg–Landau equations for a two dimensional domain which has small size. We prove that if the domain is small, then the solution has no zero, that is no vortex. More precisely, we show that the order parameter Ψ is almost constant. Additionnally, we obtain that if the domain is a disc of small radius, then any non normal solution is symmetric and unique. Then, in the case of a slab, that is a one dimensional domain, we use the same method to derive that solutions are symmetric. The proofs use a priori estimates and the Poincaré inequality.
ON THE SCALABILITY OF ON-DEMAND ROUTING PROTOCOLS FOR MOBILE AD HOC NETWORKS: AN ANALYTICAL STUDY
Authors: ARON IONUŢ D. , GUPTA SANDEEP K. S.
Published: July 2002

Wireless systems, and mobile ad hoc networks in particular, are more likely to experience transmission and routing errors than their wired counterpart. Factors like the lack of infrastructure, node mobility, and random radio link quality can contribute to significantly higher error rates in these networks. In addition, errors have a more serious impact on the network's resources, due to limitations in bandwidth and battery power inherent to the wireless ad hoc environment. This further complicates the task of designing scalable routing protocols, since larger networks are likely to experience even more errors, which may lead to slower convergence, longer end-to-end delay and unnacceptably high number of retransmissions. In this paper, we focus on the impact of error prevention and recovery on the scaling properties of on-demand protocols for ad hoc networks. Our analytical study, based on the evaluation of the Witness Aided Routing (WAR) and the Dynamic Source Routing (DSR) protocols, shows that the lack of localized intervention in handling errors translates eventually into lack of scalability, both in terms of performance and resource consumption. As route length increases, the performance of DSR degrades dramatically, especially in the presence of fluctuating wireless link quality. Even for small routes, DSR's lack of an error handling mechanism leads to very low probability of success when there is a non-zero probability that links are not bidirectional. On the other hand, WAR remains relatively insensitive both to the length of the route and to variations in mobility and call rates, and has a higher tolerance to radio link instability. This indicates that lacalized error correction can increase route effectiveness and alleviate the effects of short-lived radio link problems to an extent that allows the protocol to scale with the network size.
MECHANICAL CHARACTERISTICS OF CORONARY CIRCULATION
Authors: KAJIYA FUMIHIKO , HIRAMATSU OSAMU , GOTO MASAMI , OGASAWARA YASUO
Published: July 2002

The phase opposition of velocity waveforms between coronary arteries (predominantly diastolic) and veins (systolic) is the most prominent characteristic of coronary hemodynamics. The phase opposition indicates the importance of intramyocardial capacitance vessels, as a determinant of phasic coronary arterial and venous flows. To investigate the functional characteristics of the intramyocardial capacitance vessels and its physiological significance, we analyzed the change in venous flow following changes in coronary arterial inflow. It was shown that during diastole the intramyocardial capacitance vessels have two functional components, unstressed volume and ordinary capacitance. Unstressed volume is defined as the volume of blood in a vessel at zero transmural pressure, and it was ~5% of the volume of the myocardium. The systolic coronary venous outflow showed a significant, positive correlation with the total displaceable blood volume stored in the intramyocardial unstressed volume and ordinary capacitance. When the unstressed volume was saturated, the coronary inflow was decreased significantly, compared with that for the unsaturated condition. Thus, the increase in intramyocardial blood volume decreases the coronary arterial inflow, whereas it enhances coronary venous outflow. The latter is an interesting analogy to the Starling's law of the heart.
A MODEL FOR HUMAN VIBRATION STUDIES AND FOR PREDICTING RESPONSE TO JOLTING AND JARRING
Authors: HUANG SHYH-CHOUR , HUSTON RONALD L.
Published: July 2002

This paper presents a finite-segment, human-body model for studying whole body vibration and for studying human response to jarring and jolting (impulses). The model is a multibody system based upon previously developed models for simulating vehicle occupant response in crashes. The model has 17 bodies representing the various limbs of the human body. Nonlinear springs and dampers are used at the joints to represent soft tissue restraint forces.

The model is tested and validated with experimental data. It is then illustrated with application with random whole-body vibration and impulsive loading simulating jarring and jolting.
The Soviet computer industry
Authors: Goodman S. E. , McHenry W. K.
Published: July 2002

For the Soviet economy in general, and the Soviet computing community in particular, the last few years have been a period of unprecedented troubles and changes. The old, stable, centrally planned economic system has proven to be far more brittle than almost anyone expected; but attempts to build a market economy have fallen far short of many hopes and expectations. The net result to date is an economy in confusion and shambles (e.g., see [3, 6]).
Heterogeneous computing environments: report on the ACM SIGOPS workshop on accommodating heterogeneity
Authors: Notkin David , Hutchinson Norman , Sanislo Jan , Schwartz Michael
Published: July 2002

The ACM SIGOPS Workshop on Accommodating Heterogeneity was conducted in December 1985 in Eastbound, Wash., as a forum for an international group of fifty researchers to discuss the technical issues surrounding heterogeneous computing environments.
On the optimal nesting order for computing
N
-relational joins
Authors: Ibaraki Toshihide , Kameda Tiko
Published: July 2002

Using the nested loops method, this paper addresses the problem of minimizing the number of page fetches necessary to evaluate a given query to a relational database. We first propose a data structure whereby the number of page fetches required for query evaluation is substantially reduced and then derive a formula for the expected number of page fetches. An optimal solution to our problem is the nesting order of relations in the evaluation program, which minimizes the number of page fetches. Since the minimization of the formula is NP-hard, as shown in the Appendix, we propose a heuristic algorithm which produces a good suboptimal solution in polynomial time. For the special case where the input query is a “tree query,” we present an efficient algorithm for finding an optimal nesting order.
The solution of almost block diagonal linear systems arising in spline collocation at Gaussian points with monomial basis functions
Authors: Majaess Gouad , Keast Patrick , Fairweather Graeme , Bennett Karin R.
Published: July 2002

Numerical techniques based on piecewise polynomial (that is, spline) collation at Gaussian points are exceedingly effective for the approximate solution of boundary value problems, both for ordinary differential equations and for time dependent partial differential equations. There are several widely available computer codes based on this approach, all of which have at their core a particular choice of basis representation for the piecewise polynomials used to approximate the solutions. Until recently, the most popular approach was to use a B-spline representation, but it has been shown that the B-spline basis is inferior, both in operation counts and conditioning, to a certain monomial basis, and the latter has come more into favor. In this paper, we describe a linear algebraic equations which arise in spline collocation at Gaussian points with such a monomial basis. It is shown that the new package, which implements an alternate column and row pivoting algorithm, is a distinct improvement over existing packages from the points of view of speed and storage requirements. In addition, we describe a second package, an important special case of the first, for solving the almost block diagonal systems which arise when condensation is applied to the systems arising in spline collocation at Gaussian points, and also in other methods for solving two-point boundary value problems, such as implicit Runge-Kutta methods and multiple shooting.
Table-driven implementation of the Expm1 function in IEEE floating-point arithmetic
Authors: Tang Ping Tak Peter
Published: July 2002

Algorithms and implementation details for the function
e

x
- 1

in both single and double precision of IEEE 754 arithmetic are presented here. With a table of moderate size, the implementations need only working-precision arithmetic and are provably accurate to within 0.58 ulp.
How to sign given any trapdoor permutation
Authors: Bellare Mihir , Micali Silvio
Published: July 2002

A digital signature scheme is presented, which is based on the existence of any trapdoor permutation. The scheme is secure in the strongest possible natural sense: namely, it is secure against existential forgery under adaptive chosen message attack.
Algorithm 740: Fortran subroutines to compute improved incomplete Cholesky factorizations
Authors: Jones Mark T. , Plassmann Paul E.
Published: July 2002

Efficient and reliable code to compute incomplete Cholesky factors of sparse matrices for use as preconditioners in a conjugate gradient algorithm is described. This code implements two recently developed, improved incomplete factorization algorithms. An efficient implementation of the standard incomplete Cholesky factorization is also included.
Development and evaluation of hypermedia for museum education
Authors: Yamada Shoji , Hong Jung-Kook , Sugita Shigeharu
Published: July 2002

To define a hypermedia system's ease of use from the user's point of view, we propose three evaluation metrics: an interface shallowness metric, a downward compactness metric, and a downward navigability metric. These express both the cognitive load on users and the structural complexity of the hypermedia contents. We conducted a field study at the National Museum of Ethnology (NME) in Osaka, Japan, to evaluate our hypermedia system and to assess the suitability of our hypermedia metrics from the viewpoint of visiting members of the public. After developing a spreadsheet-type authoring system named HyperEX, we built prototype systems for use by members of the public visiting a special exhibition held at the museum. Questionnaires, interviews, automatic recording of users' navigation operations, and statistical analysis of 449 tested users yielded the following results. First, the suitability of the metrics was found to be satisfactory, indicating that they are useful for developing hypermedia systems. Second, there is a strong relationship between a system's enjoyability and its usability. Transparency and the friendliness of the user interface are the key issues in enjoyability. Finally, the quality of the video strongly affects the overall system evaluation. Video quality is determined by optimum selection of scenes, the length of the video, and appropriate audio-visual expression of the content. This video quality may become the most important issue in developing hypermedia for museum education.
An extension of Ukkonen's enhanced dynamic programming ASM algorithm
Authors: Berghel Hal , Roach David
Published: July 2002

We describe an improvement on Ukkonen's Enhanced Dynamic Programming (EHD) approximate string-matching algorithm for unit-penalty four-edit comparisons. The new algorithm has an asymptotic complexity similar to that of Ukkonen's but is significantly faster due to a decrease in the number of array cell calculations. A 42% speedup was achieved in an application involving name comparisons. Even greater improvements are possible when comparing longer and more dissimilar strings. Although the speed of the algorithm under consideration is comparable to other fast ASM algorithms, it has greater effectiveness in text-processing applications because it supports all four basic Damerau-type editing operations.
Relationships between selected organizational factors and systems development
Authors: Srinivasan Ananth , Kaiser Kate M.
Published: July 2002

Three organizational variables influence the quality of the system development process: available resources (both human and financial), external influences on the development process, and the project team's exposure to information systems. Public information and interviews with systems managers from 28 large private firms yielded data about the organizational variables. Systems project group members completed questionnaires concerning the system development process. The results indicate that human resources affect the development process positively, but increased financial resources are related to team disagreement. The degree of external influence on the system development effort needs to be carefully monitored and controlled. Systems exposure in the firm allows an increase in the degree of awareness among project group members about the different problems encountered by users and systems staff.
Computing consequences
Authors: Huff Chuck , Martin C. Dianne
Published: July 2002

How to prepare tomorrow's professionals for questions that can't always be answered with faster, better, or more technology.
A normal form for precisely characterizing redundancy in nested relations
Authors: Mok Wai Yin , Ng Yiu-Kai , Embley David W.
Published: July 2002

We give a straightforward definition for redundancy in individual nested relations and define a new normal form that precisely characterizes redundancy for nested relations. We base our definition of redundancy on an arbitrary set of functional and multivalued dependencies, and show that our definition of nested normal form generalizes standard relational normalization theory. In addition, we give a condition that can prevent an unwanted structural anomaly in nested relations, namely, embedded nested relations with at most one tuple. Like other normal forms, our nested normal form can serve as a guide for database design.
The United States
Authors: Nicolas Florence
Published: July 2002

The U.S. system for standardization and certification remains complex and misunderstood by Europeans, However, on the eve of the transatlantic dialogue, insight into this system is necessary since it influences the position of U.S. trade diplomacy.
Errata for "Trace-Driven Memory Simulation: A Survey" by Richard Uhlig and Trevor N. Mudge, June 1997 Computing Surveys
Authors: Errata
Published: July 2002

The corrected versions of the figure and table captions for "Trace-Driven Memory Simulation: A Survey" by Richard Uhlig and Trevor N. Mudge, June 1997 Computing Surveys, can be found in the online version of the article.

The title of the article by T. Thorn, as it appears on the front cover of the September 1997 issue, is incorrect. The correct title is "Programming Languages for Mobile Code."
Context-sensitive learning methods for text categorization
Authors: Cohen William W. , Singer Yoram
Published: July 2002

Two recently implemented machine-learning algorithms,
RIPPER
and
sleeping-experts for phrases
, are evaluated on a number of large text categorization problems. These algorithms both construct classifiers that allow the “context” of a word
w
to affect how (or even whether) the presence or absence of
w
will contribute to a classification. However, RIPPER and sleeping-experts differ radically in many other respects: differences include different notions as to what constitutes a context, different ways of combining contexts to construct a classifier, different methods to search for a combination of contexts, and different criteria as to what contexts should be included in such a combination. In spite of these differences, both RIPPER and sleeping-experts perform extremely well across a wide variety of categorization problems, generally outperforming previously applied learning methods. We view this result as a confirmation of the usefulness of classifiers that represent contextual information.
Techniques for interactive design using the PDE method
Authors: Ugail Hassan , Bloor Malcolm I. G. , Wilson Michael J.
Published: July 2002

Interactive design of practical surfaces using the partial differential equation (PDE) method is considered. The PDE method treats surface design as a boundary value problem (ensuring that surfaces can be defined using a small set of design parameters). Owing to the elliptic nature of the PDE operator, the boundary conditions imposed around the edges of the surface control the internal shape of the surface. Moreover, surfaces obtained in this manner tend to be smooth and fair. The PDE chosen has a closed form solution allowing the interactive manipulation of the surfaces in real time. Thus we present efficient techniques by which we show how surfaces of practical significance can be constructed interactively in real time.
Indexing and retrieval strategies for natural language fact retrieval
Authors: Kolodner Janet L.
Published: July 2002

Researchers in artificial intelligence have recently become interested in natural language fact retrieval; currently, their research is at a point where it can begin contributing to the field of Information Retrieval. In this paper, strategies for a natural language fact retrieval system are mapped out, and approaches to many of the organization and retrieval problems are presented. The CYRUS system, which keeps track of important people and is queried in English, is presented and used to illustrate those solutions.
Databsse system approach the management decision support
Authors: Donovan John J.
Published: July 2002

Traditional intuitive methods of decision-making are no longer adequate to deal with the complex problems faced by the modern policymaker. Thus systems must be developed to provide the information and analysis necessary for the decisions which must be made. These systems are called decision support systems. Although database systems provide a key ingredient to decision support systems, the problems now facing the policymaker are different from those problems to which database systems have been applied in the past. The problems are usually not known in advance, they are constantly changing, and answers are needed quickly. Hence additional technologies, methodologies, and approaches must expand the traditional areas of database and operating systems research (as well as other software and hardware research) in order for them to become truly effective in supporting policymakers.

This paper describes recent work in this area and indicates where future work is needed. Specifically the paper discusses: (1) why there exists a vital need for decision support systems; (2) examples from work in the field of energy which make explicit the characteristics which distinguish these decision support systems from traditional operational and managerial systems; (3) how an awareness of decision support systems has evolved, including a brief review of work done by others and a statement of the computational needs of decision support systems which are consistent with contemporary technology; (4) an approach which has been made to meet many of these computational needs through the development and implementation of a computational facility, the Generalized Management Information System (GMIS); and (5) the application of this computational facility to a complex and important energy problem facing New England in a typical study within the New England Energy Management Information System (NEEMIS) Project.
Reliability mechanisms for SDD-1
Authors: Hammer Micael , Shipman David
Published: July 2002

This paper presents the reliability mechanisms of SDD-1, a prototype distributed database system being developed by the Computer Corporation of America. Reliability algorithms in SDD-1 center around the concept of the Reliable Network (RelNet). The RelNet is a communications medium incorporating facilities for site status monitoring, event timestamping, multiply buffered message delivery, and the atomic control of distributed transactions.

This paper is one of a series of companion papers on SDD-1 [3, 4, 6, 13].
Monogenic Post Normal Systems of Arbitrary Degree
Authors: Hooper Philip K.
Published: July 2002

From an arbitrary Turing machine,
Z
, a monogenic Post normal system,
v
(
Z
), is constructed. It is then shown not only that the halting problem for
Z
is reducible to that of
v
(
Z
) but also that the halting problem for
v
(
Z
) is reducible to that of
Z
. Since these two halting problems are of the same degree, the halting problem for the normal system can have an arbitrary (recursively enumerable) degree of undecidability.
A Midpoint Phenomenon
Authors: Goldstein A. J. , Richman P. L.
Published: July 2002

Finite-precision interval arithmetic evaluation of a function ƒ of
n
variables at an
n
-dimensional rectangle
T
which is the Cartesian product of intervals yields an interval which is denoted by
F
(
T
). Correspondingly, finite-precision real arithmetic evaluation of ƒ at the midpoint
m
(
T
) of
T
yields a number which is denoted by
f
(
m
(
T
)) Ε
F
(
T
). Often,
f
(
m
(
T
)) is surprisingly close to
m
(
F
(
T
)). The purpose of this note is to provide some insight into this phenomenon by examining the case of infinite precision and rational functions. It is shown that if the gradient of ƒ is nonzero at a fixed point
t
Ε
T
, then as the maximum edge length
w
(
T
) of
T
approaches zero, [
m
(
F
(
T
)) - ƒ(
m
(
T
))]/
w
(
F
(
T
)) =
O
(
w
(
T
)), where
F
(
T
) and ƒ(
m
(
T
)) denote the infinite-precision results corresponding to
F
(
T
) and
f
(
m
(
T
)), respectively. More precise results are derived when ƒ is one of +, -, ×, or /.
A New Class of Automated Theorem-Proving Algorithms
Authors: Overbeek Ross A.
Published: July 2002

A procedure is defined for deriving from any statementSan infinite sequence of statementsS0,S1,S2,S3, ··· such that: (a) if there exists anisuch thatSiis unsatisfiable, thenSis unsatisfiable; (b) ifSis unsatisfiable, then there exists anisuch thatSiis unsatisfiable; (c) for allithe Herbrand universe ofSiis finite; hence, for eachithe satisfiability ofSiis decidable. The new algorithms are then based on the idea of generating successiveSiin the sequence and testing eachSifor satisfiability. Each element in the class of new algorithms is complete.
HPFBench
Authors: Hu Y. Charlie , Jin Guohua , Johnsson S. Lennart , Kehagias Dimitris , Shalaby Nadia
Published: July 2002

The high performance Fortran (HPF) benchmark suite HPFBench is designed for evaluating the HPF language and compilers on scalable architectures. The functionality of the benchmarks covers scientific software library functions and application kernels that reflect the computational structure and communication patterns in fluid dynamic simulations, fundamental physics, and molecular studies in chemistry and biology. The benchmarks are characterized in terms of FLOP count, memory usage, communication pattern, local memory accesses, array allocation mechanism, as well as operation and communication counts per iteration. The benchmarks output performance evaluation metrics in the form of elapsed times, FLOP rates, and communication time breakdowns. We also provide a benchmark guide to aid the choice of subsets of the benchmarks for evaluating particular aspects of an HPF compiler. Furthermore, we report an evaluation of an industry-leading HPF compiler from the Portland Group Inc. using the HPFBench benchmarks on the distributed-memory IBM SP2
Some factors affecting program repair maintenance
Authors: Vessey Iris , Weber Ron
Published: July 2002

An empirical study of 447 operational commercial and clerical Cobol programs in one Australian organization and two U.S. organizations was carried out to determine whether program complexity, programming style, programmer quality, and the number of times a program was released affected program repair maintenance. In the Australian organization only program complexity and programming style were statistically significant. In the two U.S. organizations only the number of times a program was released was statistically significant. For all organizations repair maintenance constituted a minor problem: over 90 percent of the programs studied had undergone less than three repair maintenance activities during their lifetime.
Beneath the surface of organizational processes
Authors: Katzenstein Gary , Lerch F. Javier
Published: July 2002

This paper raises the question, “What is an effective representation framework for organizational process design?” By combining our knowledge of existing process models with data from a field study, the paper develops criteria for an effective process representation. Using these criteria and the case study, the paper integrates the process redesign and information system literatures to develop a representation framework that captures a process' social context. The paper argues that this social context framework, which represents people's motivations, social relationships, and social constraints, gives redesigners a richer sense of the process and allows process redesigners to simultaneously change social and logistic systems. The paper demonstrates the framework and some of its benefits and limitations.
Determinants of program repair maintenance requirements
Authors: Gremillion Lee L.
Published: July 2002

Considerable resources are devoted to the maintenance of programs including that required to correct errors not discovered until after the programs are delivered to the user. A number of factors are believed to affect the occurrence of these errors, e.g., the complexity of the programs, the intensity with which programs are used, and the programming style. Several hundred programs making up a manufacturing support system are analyzed to study the relationships between the number of delivered errors and measures of the programs' size and complexity (particularly as measured by software science metrics), frequency of use, and age. Not surprisingly, program size is found to be the best predictor of repair maintenance requirements. Repair maintenance is more highly correlated with the number of lines of source code in the program than it is to software science metrics, which is surprising in light of previously reported results. Actual error rate is found to be much higher than that which would be predicted from program characteristics.
Programmers use slices when debugging
Authors: Weiser Mark
Published: July 2002

Computer programmers break apart large programs into smaller coherent pieces. Each of these pieces: functions, subroutines, modules, or abstract datatypes, is usually a contiguous piece of program text. The experiment reported here shows that programmers also routinely break programs into one kind of coherent piece which is not coniguous. When debugging unfamiliar programs programmers use program pieces called
slices
which are sets of statements related by their flow of data. The statements in a slice are not necessarily textually contiguous, but may be scattered through a program.
Shuffle languages, Petri nets, and context-sensitive grammars
Authors: Gischer Jay
Published: July 2002

Flow expressions have been proposed as an extension of the regular expressions designed to model concurrency. We examine a simplification of these flow expressions which we call
shuffle expressions
. We introduce two types of machines to aid in recognizing shuffle languages and show that one such machine may be equivalent to a Petri Net. In addition, closure and containment properties of the related language classes are investigated, and we show that one machine type recognizes at least a restricted class of shuffle languages. Finally, grammars for all shuffle languages are generated, and the shuffle languages are shown to be context-sensitive.
Real-time
Authors: Glass Robert L.
Published: July 2002

Real-time debug and test is still a “lost world” compared to the “civilization” developed in other areas of software, says Robert L. Glass. From a survey of current practice across several projects and companies, he defines a state of the art for this problem area and suggests improvements which will ease the practitioner's task.
Multiple byte processing with full-word instructions
Authors: Lamport Leslie
Published: July 2002

A method is described which allows parallel processing of packed data items using only ordinary full-word computer instructions, even though the processing requires operations whose execution is contingent upon the value of a datum. It provides a useful technique for processing small data items such as alphanumeric characters.
Weighted increment linear search for scatter tables
Authors: Luccio Fabrizio
Published: July 2002

A new linear search for hash tables whose increment step is a function of the key being addressed is presented. Comparisons with known methods are given, in terms of efficiency and computation complexity. In particular, the new method applies to tables of size
n
= 2

r

. It allows full table searching, and practically eliminates primary clustering at a very low cost.
General performance analysis of key-to-address transformation methods using an abstract file concept
Authors: Lum V. Y.
Published: July 2002

This paper presents a new approach to the analysis of performance of the various key-to-address transformation methods. In this approach the keys in a file are assumed to have been selected from the key space according to a certain probabilistic selection algorithm. All files with the same number of keys selected from this key space will be suitably weighted in accordance with the algorithm, and the average performance of the transformation methods on these files will be used as the potential of these methods. Using this analysis, methods with the same overall performance can be classified and key distributions partial to certain transformations can be identified. All this can be done analytically. The approach is applied to a group of transformation methods using files whose keys are selected randomly.
An algorithm for finding a fundamental set of cycles of a graph
Authors: Paton Keith
Published: July 2002

A fast method is presented for finding a fundamental set of cycles for an undirected finite graph. A spanning tree is grown and the vertices examined in turn, unexamined vertices being stored in a pushdown list to await examination. One stage in the process is to take the top element
v
of the pushdown list and examine it, i.e. inspect all those edges (
v, z
) of the graph for which
z
has not yet been examined. If
z
is already in the tree, a fundamental cycle is added; if not, the edge (
v, z
) is placed in the tree. There is exactly one such stage for each of the
n
vertices of the graph. For large
n
, the store required increases as
n
2
and the time as

n
γ

where
γ
depends on the type of graph involved.
γ
is bounded below by 2 and above by 3, and it is shown that both bounds are attained.

In terms of storage our algorithm is similar to that of Gotlieb and Corneil and superior to that of Welch; in terms of speed it is similar to that of Welch and superior to that of Gotlieb and Corneil. Tests show our algorithm to be remarkably efficient (
γ
= 2) on random graphs.