bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of NB Josephson Junction Properties under Optical Irradiation
Authors: Monticone E. , Rajteri M. , Maggi S. , Steni R. , Rastello M. L. , Lacquaniti V. , Pepe G. P. , Parlato L. , Ammendola G.
Published: July 2002

The gap voltage shift of Nb Josephson junctions fabricated on different substrates is measured under optical illumination at several conditions of light intensity and chopping frequency. The signal dependence on the chopping frequency for junctions realized on glass substrates is bolometer-like with a strong thermal coupling between film and substrate. The responsivity of a junction of 50 μ m × 20 μ m is 50 V/W in vacuum and at liquid helium temperature, and its time constant is lower than 10 μ s . The linearity of the response on the optical power extends over five order of magnitude. The response of junctions fabricated on silicon substrates is flat versus the chopping frequency and about 100 times lower than a junction on glass with the same incident optical power. The shift of the gap at temperatures between 1.2 K and 4.2 K has been measured to separate the nonequilibrium effects from the heating effects.
DIFFERENTIAL AND TOTAL PHONON FREQUENCY DISTRIBUTION FUNCTIONS FROM THE CORRESPONDING MEASURED TEMPERATURE DEPENDENT MEAN SQUARE DISPLACEMENTS IN AN ANISOTROPIC CRYSTAL USING UNFOLDING TECHNIQUE
Authors: TEWARI S. P. , SILOTIA POONAM , BERA KAKOLI
Published: July 2002

It is shown, for the first time, that phonon frequency distribution function (FDF) can be successfully extracted from the measured temperature dependent mean square displacement (MSD) of a particle in a condensed system using unfolding technique. In particular, the observed MSD of a Zinc atom in the basal plane, along the z direction and the total have been unfolded to obtain corresponding phonon FDF which yield much better values of the temperature dependent MSD than the trial FDF. The method can be fruitfully utilized to obtain FDF of elastic vibrations both for ordered and disordered solids from the readily available experimental MSD.
Experimental Study of the Yield Stress of Electrorheological Suspensions under AC Field: Comparison with a Theoretical Model
Authors: Boissy C. , Wu C.W. , Fahmy Y. , Conrad H.
Published: July 2002

Recently a model describing the interaction between the particles of an electrorheological suspension and the resulting properties (yield stress, current density) has been proposed by Wu and Conrad. This model takes into account both the conductivity and the permittivity of each constituent of the suspension and predicts the behavior under DC and AC fields. The goal of the present work is to compare the predictions of this model with data available in the literature and with additional experiments using DC and AC fields at frequencies up to 2000 Hz. The ER fluids used in our experiments are suspensions of different ceramics particles ( Al 2 O 3, ZrO 2, TiO 2, CaTiO 3, BaTiO 3) in silicone oil. These particles cover a wide range of permittivity and conductivity, which allows us to study the ER effect with varying values of the conductivity and/or permittivity mismatch between the particles and the liquid. The model is in reasonable accord with experiment.
OCCURRENCE OF SPIN-FLUCTUATION PAIRING IN HIGH-TEMPERATURE SUPERCONDUCTORS
Authors: Blackstead Howard A. , Dow John D.
Published: July 2002

The definitive property of a spin-fluctuation d-wave-pairing superconductor is that cuprate-plane Cu-site Ni is a weaker Cooper-pair-breaker than Zn on the same site. None of the major high-temperature superconductors, except possibly YBa 2 Cu 3 O x, exhibits this property experimentally.
A DIGITAL INDEX THEOREM
Authors: DOMÍNGUEZ E. , FRANCÉS A. R. , AYALA R. , QUINTERO A.
Published: July 2002

This paper is devoted to state and prove a Digital Index Theorem for digital (n - 1)-manifolds in a digital space (Rn, f), where f belongs to a large family of lighting functions on the standard cubical decomposition Rn of the n-dimensional Euclidean space. As an immediate consequence we obtain the corresponding theorems for all (α, β)-surfaces of Kong–Roscoe, with α, β ∈ {6, 18, 26} and (α, β) ≠ (6, 6), (18, 26), (26, 26), as well as for the strong 26-surfaces of Bertrand–Malgouyres.
A COLOR IMAGE RETRIEVAL METHOD BASED ON COLOR MOMENT AND COLOR VARIANCE OF ADJACENT PIXELS
Authors: CHAN YUNG-KUAN , CHANG CHIN-CHEN
Published: July 2002

This paper first introduces three simple and effective image features — the color moment (CM), the color variance of adjacent pixels (CVAP) and CM–CVAP. The CM feature delineates the color-spatial information of images, and the CVAP feature describes the color variance of pixels in an image. However, these two features can only characterize the content of images in different ways. This paper hence provides another feature CM–CVAP, which combines both, to raise the quality of similarity measure. The experimental results show that the image retrieval method based on the CM–CVAP feature gives quite an impressive performance.
CLONES CONTAINING MAL'TSEV OPERATIONS
Authors: IDZIAK PAWEŁ M.
Published: July 2002

It is shown that the number of clones on a k element set that contain a Mal'tsev operation and all k constants is finite iff k≤3. This answers a part of a question of Ralph McKenzie and Ivo Rosenberg from [8], who asked if, on a finite set, the number of clones containing a Mal'tsev operation can be infinite.
SILICON OXIDE DECOMPOSITION AND DESORPTION DURING THE THERMAL OXIDATION OF SILICON
Authors: STARODUB D. , GUSEV E. P. , GARFUNKEL E. , GUSTAFSSON T.
Published: July 2002

The thermal oxidation of silicon is normally considered to occur via two different routes. At higher O 2 pressures and lower temperature SiO 2 (s) film growth occurs ("passive" oxidation), while at lower O 2 pressures and higher temperature SiO(g) is desorbed in an etching process ("active" oxidation). We have measured the yield of SiO into the gas phase in a wide range of dry O 2 pressures (10-7–10-5 Torr) and Si substrate temperatures (620–870°C) in the passive as well as the active oxidation regimes. A phase diagram for silicon oxidation in this pressure–temperature region is obtained. We have found evidence for small but measurable yields of SiO(g) desorbing from the nascent oxide film during the initial stages of passive oxidation, even when the oxide film continuously covers the surface. A sensitive method for detecting volatile products based on condensation of desorbed species is described.
ADSORPTION-INDUCED SURFACE RECONSTRUCTION PROCESSES: THE INFLUENCE ON THE ADSORPTION–DESORPTION KINETICS AND THE MOBILITY OF ADSORBED ATOMS
Authors: NIETO F. , TARASENKO A. A. , PEREYRA V. , UEBING C.
Published: July 2002

In this paper we study the influence of adsorption-induced surface reconstruction on both the adsorption–desorption kinetics and the surface diffusion of adsorbed particles. The reconstruction is regarded as an order–disorder phase transition, which is described in the framework of the lattice gas formalism by the two-position (2P) model. Adsorption is studied by kinetic Monte Carlo simulations while surface diffusion coefficients are evaluated by using the classical Monte Carlo modeling. Utilizing Monte Carlo simulations we characterize how the behavior of the chemical (D), the jump (DJ) and the tracer (D*) diffusion coefficients depend on the different ordered phases predicted by the model.
EFFECTS OF SYSTEMICALLY APPLIED IGF-1 ON MOTOR NERVE RECOVERY AFTER PERIPHERAL NERVE TRANSECTION AND REPAIR IN THE RAT — A FUNCTIONAL STUDY
Authors: Lutz B. S. , Ma S.-F. , Chuang D. C. C. , Wei F.-C.
Published: July 2002

The trophic effects of systemically applied Rh insulin-like growth factor-1 (rhIGF-1) on peripheral motor nerve regeneration following transection and epineural repair in rats median nerve have been examined. RhIGF-1 (0.5 mg/kg/rat) was administered subcutaneously to the neck region of the repaired side for 14 days post-operation. Motor recovery was tested with the grasping test that is an objective quantitative behavioural assessment of regeneration of the rats median nerve. Muscle twitch tension and muscle weight were measured in the flexor digitorum sublimus muscle. No significant differences between experimental and control animals regarding onset of muscle function, recovery of muscle power, and muscle weight were found. These results demonstrate that subcutaneously applied rhIGF-1 cannot improve functional motor recovery after nerve transection and repair in the rat as has been demonstrated after nerve crushing injury. This is regarded as a consequence of specificity failure during reinnervation, which occurs after nerve transection and repair, whereas after crushing injury specific reinnervation is a common feature.
COMPOSITIONAL SPECIFICATION AND REUSE OF A GENERIC COOPERATIVE AGENT MODEL
Authors: BRAZIER FRANCES M. T. , CORNELISSEN FRANK , JONKER CATHOLIJN M. , TREUR JAN
Published: July 2002

In this paper, one of the informally described models of agent cooperation (Jennings, 1995) has been used to develop and formally specify a generic model of a cooperative agent (GCAM). The compositional development method for multi-agent systems DESIRE supported the principled design of this model of cooperation. To illustrate reusability of the generic model, two application domains have been addressed: collaborative engineering design, and Call Center support.
PRICING ASSET BACKED ISLAMIC FINANCIAL INSTRUMENTS
Authors: EBRAHIM MUHAMMED-SHAHID
Published: July 2002

The social impact of bankruptcies and loan defaults result in structural impairment of the economy. This paper presents a judicious methodology for pricing durable asset backed financing facilities while reducing their risk of default. Although the framework of the study is that of an Islamic banking system, it can also be implemented by conventional intermediaries. Both credit as well as hybrid (quasi-equity) facilities in the form of Bai' Bithman Ajil (BBA)/Ijara wal-'Iqtina and Decreasing Mudharabah (DM) instruments are discussed using computer simulation. These are applied to the cases of automobile financing and home mortgages. Placing additional assets as Rehn (security) has the capacity to improve the financing ratio and/or the term to maturity of both kinds of vehicles.
AN EMPIRICAL INVESTIGATION OF THE FORWARD INTEREST RATE TERM STRUCTURE
Authors: MATACZ ANDREW , BOUCHAUD JEAN-PHILIPPE
Published: July 2002

In this paper we study empirically the Forward Rate Curve (FRC) of 5 different currencies. We confirm and extend the findings of a previous investigation of the U.S. FRC. In particular, the average FRC follows a square-root law, with a prefactor related to the spot volatility, suggesting a Value-at-Risk-like pricing. We find a striking correlation between the instantaneous FRC and the past spot trend over a certain time horizon, in agreement with the idea of an extrapolated trend effect. We present a model which can be adequately calibrated to account for these effects.
MARKET EQUILIBRIUM WITH CAPITAL LOSS DEDUCTION OPTIONS
Authors: MURPHY AUSTIN
Published: July 2002

This research builds on a widely-cited study to prove that the permissible tax loss deduction subsidizes investments in volatile securities by materially lowering the required expected return on more volatile assets. The implications of the theory are robust to the existence of transaction costs, dividends, forced liquidations, and a ceiling on capital loss deductions in some countries. It is further shown that special tax treatment at death significantly increases the value of the tax deduction option. The theoretical model is explained to be consistent with empirical findings reported in the literature and to actually help explain some asset pricing anomalies.
CREDIT CONTAGION: PRICING CROSS-COUNTRY RISK IN BRADY DEBT MARKETS
Authors: AVELLANEDA MARCO , WU LIXIN
Published: July 2002

Credit contagion means that the credit deterioration of an entity causes the credit deterioration of other entities. In this paper, we build and test a continuous-time model for defaultable securities using a diffusive process for risk-free interest rate, and a finite-state continuous-time Markov process for the correlation of credit. The credit contagion, in particular, is established by relating transition rates of various credit states. Examples of derivative pricing with calibrated credit contagion model are provided. Initial empirical results with the benchmarks of Brady bonds show that our model is a viable new technique for the pricing and risk-managing of credit derivatives.
ON SELF-SIMILAR SOLUTIONS, WELL-POSEDNESS AND THE CONFORMAL WAVE EQUATION
Authors: PLANCHON FABRICE
Published: July 2002

We prove that the initial value problem for the conformally invariant semi-linear wave equation is well-posed in the Besov space [Formula: see text]. This induces the existence of (non-radially symmetric) self-similar solutions for homogeneous data in such Besov spaces.
FLICKER NOISE IN HETEROCYCLIC CONDUCTING POLYMER THIN FILM RESISTORS
Authors: BRUSCHI P. , NANNINI A. , NAVARRINI D. , PIOTTO M.
Published: July 2002

The power spectral density of low frequency resistance fluctuation in heterocyclic conducting polymer thin film resistors was measured at various temperatures and bias current values. An accurate calculation of the background noise was performed in order to correct the measured power spectral densities. A parameter obtained normalizing the voltage power density to the sample volume and d.c. bias is used to compare the tested conducting polymers with various materials used for resistors fabrication.
MOMENT LYAPUNOV EXPONENT FOR CONSERVATIVE SYSTEMS WITH SMALL PERIODIC AND RANDOM PERTURBATIONS
Authors: IMKELLER P. , MILSTEIN G. N.
Published: July 2002

Much effort has been devoted to the stability analysis of stationary points for linear autonomous systems of stochastic differential equations. Here we introduce the notions of Lyapunov exponent, moment Lyapunov exponent, and stability index for linear nonautonomous systems with periodic coefficients. Most extensively we study these problems for second order conservative systems with small random and periodic excitations. With respect to relations between the intrinsic period of the system and the period of perturbations we consider the incommensurable and commensurable cases. In the first case we obtain an asymptotic expansion of the moment Lyapunov exponent. In the second case we obtain a finite expansion except in situations of resonance. As an application we consider the Hill and Mathieu equations with random excitations.
Adaptive platform dynamics in multi-party spatial voting
Authors: Stadler Bärbel M. R.
Published: July 2002

The dynamics of multiple competing political parties under spatial voting is explored. Parties are allowed to modify their positions adaptively in order to gain more votes. The parties in this model are opportunistic, in the sense that they try to maximize their share of votes regardless of any ideological position. Each party makes small corrections to its current platform in order to increase its own utility by means of the steepest ascent in the variables under its own control, i.e., by locally optimizing its own platform.

We show that in models with more than two parties bifurcations at the trivial equilibrium occur if only the voters are critical enough, that is, if they respond strongly to small changes in relative utilities. A numerical survey in a three-party model yields multiple bifurcations, multi-stability, and stable periodic at tractors that arise through Hopf bifurcations. Models with more than two parties can thus differ substantially from the two-party case, where it has been shown that under the assumptions of quadratic voter utilities and complete voter participation there is always a globally stable equilibrium that coincides with the mean voter position.
CALIBRATION, REGISTRATION, AND PREPARATION OF AN AUGMENTED REALITY ENVIRONMENT FOR VIRTUAL PROTOTYPING OF DYNAMIC SYSTEMS
Authors: HUANG C. P. , AGARWAL S. , LIOU F. W.
Published: July 2002

The aim of this research is develop an effective virtual prototyping system for product development using augmented reality technology. Before a virtual environment is put into work for design and development, some way of quantifying errors or uncertainties in the computer model is needed so that a robust and reliable system can be achieved. This paper presents the calibration, registration, and preparation of an augmented reality environment with 3D tracking and dynamic simulation technologies for studying dynamic systems, such as parts orientation devices. With such virtual prototyping techniques, engineers can run high-fidelity simulation to test new materials, components, and systems before investing valuable resources in construction of physical prototypes.
A storage and access manager for ill-structured data
Authors: Kottemann Jeffrey , Gordon Michael , Stott Jack
Published: July 2002

Database management systems are powerful tools for processing large volumes of structured, or normalized, data. Much of the data to be stored in computer systems, however, differs from normalized data in both its
logical
uses and the
storage structure
required for its effective management. For instance, Van Rijsbergen (1979) distinguishes database retrieval from
information retrieval (IR)
—the retrieval of references to text—by comparing the following logical characteristics of IR systems to database management systems: IR Systems employ partial (vs. exact) matching; they are built on an underlying probabilistic (vs. deterministic) model; they classify information on a polythetic (vs. monothetic) basis, and queries are incompletely (vs. completely) specified. Similarly, other forms of relatively ill-structured data such as semantic networks [15]—which require property inheritance, and production rules—which must be joined in logical chains also differ in their logical use from normalized record structures.
Interpolatory integration formulas for optimal composition
Authors: Favati Paola , Lotti Grazia , Romani Francesco
Published: July 2002

A set of symmetric, closed, interpolatory integration formulas on the interval [-1, 1] with positive weights and increasing degree of precision is introduced. These formulas, called recursive monotone stable (RMS) formulas, allow applying higher order or compound rules without wasting previously computed functional values. An exhaustive search shows the existence of 27 families of RMS formulas, stemming from the simple trapezoidal rule.
Using annotations to support multiple kinds of versioning in an object-oriented database system
Authors: Sciore Edward
Published: July 2002

The concept of
annotation
from object-oriented languages is adapted to object-oriented databases. It is shown how annotations can be used to model activities such as constraint checking, default values, and triggers. Annotations also are an appropriate way to model different versioning concepts. This paper discusses three kinds of versioning—histories, revisions, and alternatives—and demonstrates how each one can be modeled effectively using annotations. The use of annotations also allows other kinds of versioning to be defined extensibly, and arbitrary combinations of versions can be handled easily.
The Metal system
Authors: Gajek Oliver
Published: July 2002

Siemens Nixdorf Information Systems has created a machine translation system called Metal that supports the following language pairs: German-English; English-German; German-Spanish; French-Dutch; Dutch-French. (Work on other language pairs is underway.
The automated production control documentation system
Authors: Trammell Carmen J. , Binder Leon H. , Snyder Cathrine E.
Published: July 2002

A prototype software system was developed for the U.S. Naval Underwater Systems Center(NUSC) as a demonstration of the Cleanroom Software Engineering methodology. The Cleanroom method is a team approach to the incremental development of software under statistical quality control. Cleanroom's formal methods of Box Structure specification and design, functional verification, and statistical testing were used by a four-person team to develop the Automated Production Control Documentation(APCODOC) system, a relational database application. As is typical in Cleanroom developments, correctness of design and code were ensured through team reviews. Eighteen errors were found during functional verification of the design, and nineteen errors were found during walkthrough of the 1820 lines of FOXBASE code. The software was not executed by developers prior to independent testing (i.e., there was no debugging). There were no errors in compilation, no failures during statistical certification testing, and the software was certified at the target levels of reliability and confidence. Team members attribute the ultimate error-free compilation and failure-free execution of the software to the rigor of the methodology and the intellectual control afforded by the team approach.
The human element
Authors: Neumann Peter G.
Published: July 2002

In past issues we have discussed various system-related disasters and their causes, both accidental and intentional. In almost all cases it is possible to allocate to people—directly or indirectly—those difficulties allegedly attributed to “computer problems.” But too much effort seems directed at placing blame and identifying scapegoats, and not enough on learning from experiences and avoiding such problems [1,2,5,6,7]. Besides, the real causes may implicitly or explicitly involve a multiplicity of developers, customers, users, operators, administrators, others involve with computer and communication systems, and sometimes even unsuspecting bystanders. In a few cases the physical environment also contributes, e.g., power outages, floods, extreme weather, lightning, and earthquakes. Even in those cases there may have been system people who failed to anticipate the possible effects. In principle, at least, we can design redundantly distributed systems that are able to withstand certain hardware faults, component unavailabilities, extreme delays, human errors, malicious misuse, and even “acts of God”—at least within limits. Nevertheless, in surprisingly many systems (including systems designed to provide continuous availability), an entire system can be brought to a screeching halt by a simple event just as by a complex one [4].
A prototyping environment for differential equations
Authors: Boubez Toufic I. , Froncioni Andy M. , Peskin Richard L.
Published: July 2002

A system is presented to allow end users to solve nonlinear differential equations without need to write computer programs. The system treats
n
th order space (one dimensional), first order time systems with initial and/or two point boundary value specification. Users of the system need only enter the problem in direct mathematical notation, and output is automatically presented as a solution graph. The system allows the user to alter this equations, in-situ, that is to computationally steer his model. Thus the system is suited for model prototyping. Implementation is based on an object-oriented paradigm, well established and robust numerical procedures, and distributed computing to supported needed resources for numerically intensive tasks.
On Roth, Korth, and Silberschatz's extended algebra and calculus for nested relational databases
Authors: Tansel Abdullah U. , Garnett Lucy
Published: July 2002

We discuss the issues encountered in the extended algebra and calculus languages for nested relations defined by Roth, Korth, and Silberschatz.[4]. Their equivalence proof between algebra and calculus fails because of the keying problems and the use of extended set operations. Extended set operations also have unintended side effects. Furthermore, their calculus seems to allow the generation of power sets, thus making it more powerful than their algebra.
Estimating accesses in partitioned signature file organizations
Authors: Ciaccia Paulo , Zezula Pavel
Published: July 2002

We show that performance of some basic methods for the partitioning of signature files, namely Quick Filter and Fixed Prefix, can be easily evaluated by means of a closed formula. The approximation is based on well-known results from probability theory, and, as shown by simulations, introduces no appreciable errors when compared with the exact, cumbersome formulas used so far. Furthermore, we prove that the exact formulas for the two methods coincide. Although this does not imply that the two methods behave in the same way, it sheds light on the way they could be compared.
OBSERV—a prototyping language and environment
Authors: Tyszberowicz Shmuel , Yehudai Amiram
Published: July 2002

The OBSERV methodology for software development is based on rapid construction of an executable specification, or prototype, of a systems, which may be examined and modified repeatedly to achieve the desired functionality. The objectives of OBSERV also include facilitating a smooth transition to a target system, and providing means for reusing specification, design, and code of systems and subsystems. We are particularly interested in handling embedded systems, which are likely to have concurrency and have some real-time requirements.

The OBSERV prototyping language combines several paradigms to express the behavior of a system. The object-oriented approach provides the basic mechanism for building a system from a collection of objects, with well-defined interfaces between them. We use finite-state machines to model the behavior of individual objects. At a lower level, activities that occur within objects, either upon entry to a state or in transition between thus allowing a nonprocedural description.

The environment provided to a prototype builder is as important as the language. We have made an attempt to provide flexible tools for executing or simulating the prototype being built, as well as for browsing and static checking. The first implementation of the tools was window based but not graphic. A graphic front end, name CRUISE, was developed afterwards.

A simulation sequence focuses on a single object, which can be as complex as necessary, possibly the entire system, and expects all the interactions between it and the outside world to be achieved by communication between the simulator and the user. The simulator allows the user to easily switch back and forth from one object to another, simulating each object in isolation.

To enable testing the behavior of a prototype in a realistic environment, it is possible to construct objects that imitate the environment objects. We also allow simulation of systems with missing pieces, by calling upon the user to simulate any such missing piece by himself.
The intractability of bounded protocols for on-line sequence transmission over non-FIFO channels
Authors: Mansour Yishay , Schieber Baruch
Published: July 2002

The efficiency of data-link protocols for reliable transmission of a sequence of messages over non-FIFO physical channels is discussed. The transmission has to be on-line; i.e., a message cannot be accessed by the transmitting station before the preceding message has been received. Three resources are considered: The number of packets that have to be sent, the number of headers, and the amount of space required by the protocol. Three lower bounds are proved. First, the space required by any protocol for delivering
n
messages that uses less than
n
headers cannot be bounded by any function of
n
. Second, the number of packets that have to be sent by any protocol that uses a fixed number of headers in order to deliver a message is linear in the number of packets that are delayed on the channel at the time the message is sent. Finally, the notion of a probabilistic physical channel, in which a packet can be delayed on the channel with probability
q
, is introduced. An exponential lower bound, with overwhelming probability, is proved on the number of packets that have to be sent by any data-link protocol using a fixed number of headers when it is implemented over a probabilistic physical channel.
Intelligent database caching through the use of page-answers and page-traces
Authors: Kamel Nabil , King Roger
Published: July 2002

In this paper a new method to improve the utilization of main memory systems is presented. The new method is based on prestoring in main memory a number of query answers, each evaluated out of a single memory page. To this end, the ideas of page-answers and page-traces are formally described and their properties analyzed. The query model used here allows for selection, projection, join, recursive queries as well as arbitrary combinations. We also show how to apply the approach under update traffic. This concept is especially useful in managing the main memories of an important class of applications. This class includes the evaluation of triggers and alerters, performance improvement of rule-based systems, integrity constraint checking, and materialized views. These applications are characterized by the existence at compile time of a predetermined set of queries, by a slow but persistent update traffic, and by their need to repetitively reevaluate the query set. The new approach represents a new type of intelligent database caching, which contrasts with traditional caching primarily in that the cache elements are derived data and as a consequence, they overlap arbitrarily and do not have a fixed length. The contents of the main memory cache are selected based on the data distribution within the database, the set of fixed queries to preprocess, and the paging characteristics. Page-answers and page-traces are used as the smallest indivisible units in the cache. An efficient heuristic to select a near optimal set of page-answers and page-traces to populate the main memory has been developed, implemented, and tested. Finally, quantitative measurements of performance benefits are reported.
Synchronous relaxation for parallel simulations with applications to circuit-switched networks
Authors: Eick Stephen G. , Greenberg Albert G. , Lubachevsky Boris D. , Weiss Alan
Published: July 2002

Synchronous relaxation
, a new, general-purpose, efficient method for parallel simulation, is proposed. The method is applied to obtain a new parallel algorithm for simulating large circuit-switched communication networks. To show that synchronous-relaxation method is efficient, we present the results of circuit-switched network simulation experiments, and analytic approximations derived from a mathematical model of the simulation method.
Corrigendum: Algorithm 729: FORTRAN subroutines for general Toeplitz systems
Authors: Hansen Per Christian , Chan Tony F.
Published: July 2002

This paper presents FORTRAN 77 implementations of the lookahead Levinson algorithm of Chan and Hansen (7, 8) for solving symmetric indefinite and general Toeplitz systems. The algorithms are numerically stable for all Toeplitz matrices that do not have many consecutive ill-conditioned leading principal submatrices, and also produce estimates of the algorithm and matrix condition numbers. In contrast, the classical Levinson algorithm is only guaranteed to be numerically stable for symmetric positive definite Toeplitz matrices, and no condition estimate is produced.
A logic-based foundation of discrete event modeling and simulation
Authors: Radiya Ashvin , Sargent Robert G.
Published: July 2002

A logic-based foundation of discrete event modeling and simulation is presented by defining (1) its fundamental concepts and terms from a perspective commonly held by logicians, (2) a modal Discrete Event Logic

L
DE

. The ways of expressing models using

L
DE

are discussed and compared with the ways of expressing models in simulation languages that support the event scheduling world view. The logic-based foundation provides fundamentally new insights. It asserts that events are logical propositions and the use of temporal operators is implicit in discrete event modeling and simulation languages. However, existing languages utilize only a few temporal operators in a restricted manner. The logic-based foundation enhances the ways of expressing models by using the operators implicit in existing languages in more general ways, new operators, and a parallel connective ||. The logic

L
DE

and notions implicit in it form a new framework for understanding, defining, and studying logical combinations of events, variables, and time, and expressions containing a wide range of temporal operators including next, if, when, whenever, until, while, unless, and at.
A single-exponential upper bound for finding shortest paths in three dimensions
Authors: Reif John H. , Storer James A.
Published: July 2002

We derive a single-exponential time upper bound for finding the shortest path between two points in 3-dimensional Euclidean space with (nonnecessarily convex) polyhedral obstacles. Prior to this work, the best known algorithm required double-exponential time. Given that the problem is known to be PSPACE-hard, the bound we present is essentially the best (in the worst-case sense) that can reasonably be expected.
A primal null-space affine-scaling method
Authors: Kim K. , Nazareth J. L.
Published: July 2002

This article develops an affine-scaling method for linear programming in standard primal form. Its descent search directions are formulated in terms of the null-space of the linear programming matrix, which, in turn, is defined by a suitable basis matrix. We describe some basic properties of the method and an experimental implementation that employs a periodic basis change strategy in conjunction with inexact computation of the search direction by an iterative method, specifically, the conjugate-gradient method with diagonal preconditioning. The result of a numerical study on a number of nontrivial problems representative of problems that arise in practice are reported and discussed.

A key advantage of the primal null-space affine-scaling method is its compatibility with the primal simplex method. This is considered in the concluding section, along with implications for the development of a more practical implementation.
Projectively invariant intersection detections for solid modeling
Authors: Niizeki Masatoshi , Yamaguchi Fujio
Published: July 2002

An intersection detection method for solid modeling which is invariant under projective transformations is presented. We redefine the fundamental geometric figures necessary to describe solid models and their dual figures in a homogeneous coordinate representation. Then we derive conditions, which are projectively invariant, for intersections between these primitives. We will show that a geometric processor based on the 4 x 4 determinant method is applicable to a wide range of problems with little modification. This method has applications in intersection detections of rational parametric curves and surfaces and hidden-line/surface removal algorithms.
Intersecting solids on a massively parallel processor
Authors: Karasick Michael , Strip David
Published: July 2002

Solid modeling underlies many technologies that are key to modern manufacturing. These range from CAD systems to robot simulators, from finite-element analysis to integrated circuit process modeling. The accuracy, and hence the utility, of these models is often constrained by the amount of computer time required to perform the desired operations. In this paper we present, in detail, an efficient algorithm for parallel intersections of solids using the Connection Machine, a massively parallel SIMD processor. We describe the data structure for representing the solid models and detail the intersection algorithm, giving special attention to implementation issues. We provide performance results, comparing the parallel algorithm to a serial intersection algorithm.
Algorithm 744: a stochastic algorithm for global optimization with constraints
Authors: Rabinowitz F. Michael
Published: July 2002

A stochastic algorithm is presented for finding the global optimum of a function of
n
variables subject to general constraints. The algorithm is intended for moderate values of
n
, but it can accommodate objective and constraint functions that are discontinuous and can take advantage of parallel processors. The performance of this algorithm is compared to that of the Nelder-Mead Simplex algorithm and a Simulated Annealing algorithm on a variety of nonlinear functions. In addition, one-, two-, four-, and eight-processor versions of the algorithm are compared using 64 of the nonlinear problems with constraints collected by Hock and Schittkowski. In general, the algorithm is more robust than the Simplex algorithm, but computationally more expensive. The algorithm appears to be as robust as the Simulated Annealing algorithm, but computationally cheaper. Issues discussed include algorithm speed and robustness, applicability to both computer and mathematical models, and parallel efficiency.
Computer vulnerabilities
Authors: Neumann Peter G.
Published: July 2002

The online Risks Forum has long been a hotbed for discussions of the relative merits of openness relating to the dissemination of knowledge about security vulnerabilities. The debate has now been rekindled, and is summarized here.
Death from above
Authors: Barlow John Perry
Published: July 2002

Over the last 30 years, the American CEO corps has included an astonishingly large percentage of men who piloted bombers during World War II. For some reason not so difficult to guess, dropping explosives on people from commanding heights served as a great place to develop a worldview compatible with the management of a large post-war corporation.
Self-Assessment Procedure XXIII
Authors: Clifton Mitchell H.
Published: July 2002

This is the 23rd Self-Assessment Procedure.
1
The purpose of this procedure is to let its readers test their knowledge of some of the more important features of significant programming languages. The features of imperative languages like Fortran, Algol 60, PL/I, Pascal, Modula-2, C, and Ada considered are data types, data structures, control structures, program units, scope of names, and parameter passing. Some of the corresponding features of functional languages like Lisp, logic programming languages like Prolog, and ohject-oriented programming languages like C++ and Smalltalk, are reviewed. Finally brief consideration is given to syntax and semantics, chiefly by reference to the Backus-Naur form, BNF. The features of programming languages affect all aspects of programming, including the ease of writing and maintaining programs, the reliahility of software, and the efficiency and portability of programs. Knowledge of programming language concepts and constructs is of importance to software developers, programmers, and designers of programming languages and compilers. The topic of this procedure should be of interest to any computer science student or practitioner who wishes to test his or her knowledge and learn more about one of the most important and broad areas in the computer field. The language used most often in the questions is Pascal, with Ada, Lisp, and Prolog also featured prominently. A glossary is included which defines some of the terms used in the procedure. The questions are either multiple-choice or short answer. Some of the multiple-choice questions allow for more than one correct answer.
Standards: free or sold?
Authors: Rada Roy , Berg John
Published: July 2002

Why do some standards development organizations (SDOs) provide standards for free and others charge significant amounts of money for them? The fees from the sale of standards and the stringent policies on sharing copies of standards may decrease the number of people who access these documents and may thus reduce the impact of the standards.
ATM network
Authors: Kim B. G. , Wang P.
Published: July 2002

Asynchronous transfer mode (ATM) can provide both circuit and packet-switching services with the same protocol, and this integration of circuit and packet-switching services can be beneficial in many ways. Four major benefits of the ATM technique are considered here: scalability, statistical multiplexing, traffic integration, and network simplicity. In the course of achieving those benefits, ATM makes compromises. In this article we assess the benefits and ensuing penalties of these compromises and put them into perspective.
The University of California CD-ROM Information System
Authors: Merrill Deane , Parker Nathan , Gey Fredric , Stuber Chris
Published: July 2002

The University of California CD-ROM Information System replaces the equivalent of 260,000 books of published federal statistics with a CD-ROM-based online information system. The size of this database is currently 270 CD-ROMs (135GB). It contains 1990 U.S. census data (approximately 3,000 items of socio-economic and demographic information, including race-ethnicity, employment, income, educational level, and poverty) for every block and census tract in the U.S., as well as U.S. foreign trade data by commodity from every city in the U.S. to every country in the world. It also contains the digitized map outline boundary data for city blocks for the entire U.S. (census TIGER files).
Building the interspace
Authors: Schatz Bruce
Published: July 2002

The University of Illinois is building a large-scale digital library testbed, planned to grow to thousands of users and thousands of documents, with the goal of bringing professional quality search and display to Internet information services. Concurrently, research is designing and implementing a prototype of the Interspace, a vision of what the Internet will evolve into where the distributed network of interconnected machines is replaced by a distributed space of interlinked information.
A test problem generator for large-scale unconstrained optimization
Authors: Dembo R. S. , Steihaug T.
Published: July 2002

A test problem generator for large-scale unconstrained optimization is described. It permits the generation of a poorly or well-conditioned problems of arbitrary size, derived from nonlinear network flow models. An eigenvalue analysis provides bounds on the condition number of the Hessian of the objective function and an example of an efficient preconditioner, using these bounds, is outlined.
Least-squares fitting using orthogonal multinomials
Authors: Bartels Richard H. , Jezioranski John J.
Published: July 2002

Forsythe has given a method for generating basis polynomials in a single variable that are orthogonal with respect to a given inner product. Weisfeld later demonstrated that Forsythe's approach could be extended to polynomials in an arbitrary number of variables. In this paper we sharpen Weisfeld's results and present a method for computing weighted, multinomial, least-squares approximations to given data.
An evaluation of some new cyclic linear multistep formulas for stiff ODEs
Authors: Tischer P. E. , Gupta G. K.
Published: July 2002

We evaluate several sets of cyclic linear multistep formulas (CLMFs). One of these sets was derived by Tischer and Sacks-Davis. Three new sets of formulas have been derived and we present their characteristics.

The formulas have been evaluated by comparing the performance of four versions of a code which implements CLMFs. The four versions are very similar and each version implements one of the sets of CLMFs being studied. We compare the performance of these codes with that of a widely used code, LSODE. One of the new sets of CLMFs is not only much more efficient in solving stiff problems that have a Jacobian with eigenvalues close to the imaginary axis but is almost as efficient as LSODE in solving other problems. This is a significant improvement over the ony other CLMF code available, STINT from Tendler, Bickart, and Picel.
Object-oriented AI
Authors: Harmon Paul
Published: July 2002

Computer journals and magazines are currently filled with stories about object technology, just as they were filled with stories about artificial intelligence (AI) and expert systems in the early 1980s. The naive reader might think that expert systems technology had failed and that object-oriented technology was the hot new software approach of the 1990s.
Smalltalk training
Authors: Auer Ken
Published: July 2002

Smalltalk was originally intended to make the computer more accessible. However, although the language itself is simple, it is becoming common knowledge that becoming truly proficient with the Smalltalk environment is no simple achievement. Although we are still far short of being able to inject all the wisdom of a seasoned Smalltalk guru into a guru-wanna-be in a few short weeks, the industry has become more efficient in spreading the knowledge, while its education processes have matured. The effectiveness of the training available today for objects and Smalltalk exceeds that of many of the other technologies with which we are becoming inundated. This is especially true when one realizes the significant difference between Smalltalk and other technologies and the relatively wide gulf between the known and the unknown.
A fast, low-space algorithm for multiplying dense multivariate polynomials
Authors: Alagar Vangalur S. , Probst David K.
Published: July 2002

This paper presents an improved adaptive hybrid algorithm for multiplying dense multivariate polynomials that is both time and space efficient. The hybrid algorithm makes use of two families of univariate algorithms, one Karatsuba based and the other DFT based, which are applied recursively to solve the multivariate problem. The hybrid algorithm is adaptive in that particular univariate algorithms are selected at run time to minimize the time complexity; an order-of-magnitude speedup with respect to classical multiplication is achieved over the entire practical range except for very small problems. Empirical investigation shows that most of the theoretical superiority is maintained in actual implementation. The largest contribution to the space requirements of the total algorithm is determined by the univariate algorithm used for the outermost variable; except for quite small problems, selecting univariate algorithms to minimize run time almost always leads to situations where the space requirements of the total algorithm are extremely close to the space required merely to store the result.
Linear-time suffix parsing for deterministic languages
Authors: Nederhof Mark-Jan , Bertsch Eberhard
Published: July 2002

We present a linear-time algorithm to decide for any fixed deterministic context-free language
L
and input string
w
whether
w
is a suffix of some string in
L
. In contrast to a previously published technique, the decision procedure may be extended to produce syntactic structures (parses) without an increase in time complexity. We also show how this algorithm may be applied to pocess incorrect input in linear time.
An optimal clock period selection method based on slack minimization criteria
Authors: Chang En-Shou , Gajski Daniel D. , Narayan Sanjiv
Published: July 2002

An important decision in synthesizing a hardware implementation from a behavioral description is selecting the clock period to schedule the datapath operations into control steps. Prior to scheduling, most existing behavioral synthesis systems either require the designer to specify the clock period explicitly or require that the delays of the operators used in the design be specified in multiples of the clock period. An unfavorable choice of clock period could result in operations being idle for a large portion of the clock period and, consequently, affect the performance of the synthesized design. In this article, we demonstrate the effect of clock slack on the performance of designs and present an algorithm to find a slack-minimal clock period. We prove the optimality of our method and apply it to several examples to demonstrate its effectiveness in maximizing design performance.