bluuebunny/crossref_metadata_2025 huggingface dataset:
Carapace and mandibles ontogeny in the Dendrobranchiata (Decapoda), Euphausiacea, and Mysidacea (Crustacea): a phylogenetic interest
Authors: Casanova Bernadette , Jong Laetitia De , Moreau Xavier
Published: July 2002

The ontogeny of the carapace and the mandibles has been studied for one species of Dendrobranchiata (Decapoda), four species of Euphausiacea, and three species of Mysidacea (one species of Lophogastrida and two species of Mysida). The protocephalic origin of the carapace, which arises from the antennar tergite, is confirmed. During larval development the progressive dorsal insertion of the carapace leads to the opening of the tergites of both cephalic and thoracic segments. The opening of the eight thoracic segments (TS) occurs in Euphausiacea and Decapoda only, and is done in three steps (TS1; TS1TS3 or TS1TS4; TS1TS8). In adult Mysidacea, the insertion of the carapace exhibits two levels of evolution (opening of TS1 in Gnathophausia species and of TS1TS4 in the others). Thus, in the larvae of Euphausiacea and Decapoda, the most evolved taxa, the progressive insertion of the carapace corresponds to the carapace locations in the adults of the most ancient taxa, i.e., Mysidacea. The location of the internal musculature of the mandibles, which is known for certain to characterize the different parts of the arthropodial segment, and their development, shows that the gnathal part of each mandible is prolonged by a pleural part and half the residual tergite of the mandibular segment.
C1 MODELING WITH HYBRID MULTIPLE-SIDED A-PATCHES
Authors: XU GUOLIANG , BAJAJ CHANDRAJIT L. , EVANS SUSAN
Published: July 2002

We propose a new scheme for modeling a smooth interpolatory surface, from a surface discretization consisting of triangles, quadrilaterals and pentagons, by algebraic surface patches which are subsets of real zero contours of trivariate rational functions defined on a collection of tetrahedra and pyramids. The rational form of the modeling function provides enough degrees of freedom so that the number of the surface patches is significantly reduced, and the surface has quadratic recover property.
BLACK HOLE ENTROPY BY THE BRICK-WALL METHOD IN FOUR AND FIVE DIMENSIONS WITH U(1) CHARGES
Authors: ABDALLA ELCIO , CORREA-BORBONET L. ALEJANDRO
Published: July 2002

Using the brick-wall method we compute the statistical entropy of a scalar field in a nontrivial background, in two different cases. These backgrounds are generated by four- and five-dimensional black holes with four and three U(1) charges respectively. The Bekenstein entropy formula is generally obeyed, but corrections are discussed in the latter case.
ACCOUNTING FOR THE FINITENESS OF THE HIGGS–BOSON MASS IN THE 3D GEORGI–GLASHOW MODEL
Authors: ANTONOV DMITRI
Published: July 2002

(2 + 1)-dimensional Georgi–Glashow model is explored in the regime when the Higgs boson is not infinitely heavy, but its mass is of the same order of magnitude as the mass of the W-boson. In the weak-coupling limit, the Debye mass of the dual photon and the expression for the monopole potential are found. The cumulant expansion applied to the average over the Higgs field is checked to be convergent for the known data on the monopole fugacity. These results are further generalized to the SU (N)-case. In particular, it is found that the requirement of convergence of the cumulant expansion establishes a certain upper bound on the number of colors. This bound, expressed in terms of the parameter of the weak-coupling approximation, allows the number of colors to be large enough. Finally, the string tension and the coupling constant of the so-called rigidity term of the confining string are found at arbitrary number of colors.
PERTURBATIVE QUANTUM FIELD THEORY
Authors: STERMAN GEORGE
Published: July 2002

This talk introduces perturbative quantum field on a heuristic level. It is directed at an audience familiar with elements of quantum mechanics, but not necessarily with high energy physics. It includes a discussion of the strategies behind experimental tests of fundamental theories, and of the field theory interpretations of these tests.
THE ROLE OF DIAGONALIZATION WITHIN A DIAGONALIZATION/MONTE CARLO SCHEME
Authors: Lee Dean
Published: July 2002

We discuss a method called quasi-sparse eigenvector diagonalization which finds the most important basis vectors of the low energy eigenstates of a quantum Hamiltonian. It can operate using any basis, either orthogonal or non-orthogonal, and any sparse Hamiltonian, either Hermitian, non-Hermitian, finite-dimensional, or infinite-dimensional. The method is part of a new computational approach which combines both diagonalization and Monte Carlo techniques.
NATURE OF ANTIPROTON PRODUCTION IN HIGH ENERGY NUCLEAR COLLISIONS: ASSORTED DATA VERSUS SPECIFIC MODELS
Authors: GUPTAROY P. , BHATTACHARYYA D. P. , DE BHASKAR , BHATTACHARYYA S.
Published: July 2002

We attempt here to deal with some of the important characteristics of secondary antiproton production in various high energy nuclear interactions on the basis of a model for production of particles in PP collisions. The results have, thereafter, been converted to those for AA collisions through an appropriate mechanism. The effect of rescattering and cascading in the production processes and on the chosen models has also been incorporated in a phenomenological manner. Comparison of the calculated results with data on the relevant observables leads to a striking agreement and this fair success is claimed here to obviously signal the strength of the basic models that are applied in the present work.
PERTURBATIVE CASIMIR ENERGIES OF SPHERES: TOWARDS RE-ORIENTING AND AGENDA
Authors: BARTON G.
Published: July 2002

The Casimir energies of single bodies (as opposed to the interaction between mutually disjoint bodies) have accumulated deceptive folklore which this talk will try to exorcise, by mean of calculations for atomic solids that, though optically dilute, are realistically dispersive. This is easy, because quantum electrodynamics then yields identically the same energy as one gets from the properly retarded interatomic potentials. The problem of regularizing (nominal) divergences turns out to be quite distinct from the appropriate process of renormalization: simply discarding all nominally divergent contributions would prevent one from understanding the physics. Contrary to legend, the pertinent Casimir energies for dielectric spheres are attractive.
SELF-ENERGY REVISION OPERATOR THEORY FOR THE MANY-BODY PROBLEM: APPLICATION TO DYNAMICAL PROPERTIES OF THE ELECTRON GAS
Authors: TAKADA YASUTAMI
Published: July 2002

An approximation scheme is proposed for implementing the algorithm to obtain the exact self-energy in the many-body problem [Phys. Rev.B52, 12708 (1995)]. This scheme relates the self-energy revision operator ℱ, the key quantity in the algorithm, with fxc(q,ω) the frequency-dependent exchange-correlation kernel appearing in the time-dependent density functional theory. We illustrate this scheme by applying it to the calculation of dynamic properties of the electron gas at metallic densities.
NONLINEAR DYNAMICS AND APPLICATION OF LASER-DIODE-PUMPED MICROCHIP SOLID-STATE LASERS WITH OPTICAL FEEDBACK
Authors: KO JING-YUAN , OHTOMO TAKAYUKI , ABE KAZUTAKA , OTSUKA KENJU
Published: July 2002

This paper reviews our recent research on nonlinear dynamics of microchip solid-state lasers subjected to delayed optical feedback. Instabilities in two types of physical systems including multimode lasers with feedback and lasers with frequency-shifted feedback are discussed. Applications of microchip lasers with feedback to shot-noise-limited self-mixing optical sensing and imaging are summarized.
PHONON-INDUCED FEATURES IN OPTICAL SPECTRA OF QUANTUM DOTS: BREAKDOWN OF THE ADIABATIC APPROXIMATION
Authors: DEVREESE J. T. , FOMIN V. M. , KLIMIN S. N.
Published: July 2002

A theory of photoluminescence and Raman scattering in semiconductor quantum dots is developed, which relies on two key ingredients. First, it takes into account non-adiabaticity of the exciton-phonon system. Second, it includes a multimode dielectric model of LO-phonons and of the electron-phonon interaction in confined systems. Our approach is applied to calculate the optical spectra of several quantum-dot structures: ensembles of spherical CdSe, CdSe x S 1-x and PbS quantum dots, self-assembled InAs/GaAs and CdSe/ZnSe quantum dots, brick-shaped InAs/GaAs quantum dots created by local anodic oxidation using the atomic force microscope.
Progress Update in Magnetorheological Finishing
Authors: Kordonski William , Golini Don
Published: July 2002

In magnetorheological finishing (MRF), magnetically stiffened magnetorheological (MR) abrasive fluid flows through a preset converging gap that is formed by a workpiece surface and a moving rigid wall, to create precise material removal and polishing. Theoretical analysis of MRF, based on Bingham lubrication theory, illustrates that the formation of a core attached to the moving wall results in dramatically high stress on the workpiece surface. A correlation between surface stress on the workpiece and material removal is obtained. A unique attribute of the MRF process is its determinism. MRF has been successfully implemented to polish optical surfaces to very high precision. MRF reduces the surface micro roughness of optical materials to ≤ 10A. Figure errors are corrected to a fraction of a wavelength of light and subsurface damage is removed. A wide range of optical surface shapes, including aspheres, has been polished on many different materials. Other applications in precision finishing are being considered, including integrated circuits and advanced ceramics.
SPIN AND CHARGE PSEUDOGAPS FOLLOWING KONDO EFFECT IN THE NORMAL STATE OF THE UNDERDOPED CUPRATES
Authors: MOJUMDER M. A.
Published: July 2002

A study of experimental results on various parameters of underdoped cuprates in the normal state combined with analytic calculation of Hall parameters assuming a two-channel Kondo model for the system leads to the conclusion that the spin and charge pseudogaps are, respectively, a Kondo hybridisation gap and an incipient d-wave "superconducting" gap. The former occurs due to resonant scattering of doped holes by the magnetic Cu 2+ ions while the latter occurs due to incoherent Cooper pairing of Kondo-compensated quasi-itinerant Cu d-orbitals via exchange of spin excitations. We comment on the essential similarity of the high-T c and heavy fermion superconductors and a certain crossover at lower temperatures from the two-channel to the one-channel Kondo model. An expression has been derived for the Kondo contribution to the spectral function of the charge pseudogap. We believe this work unravels the long-standing conundrum of the high-T c cuprates.
IMPROVING n+pp+ SINGLE CRYSTALLINE SILICON SOLAR CELLS BY LONG HIGH TEMPERATURE Al ANNEALING
Authors: Santana Guillermo , Morales-Acevedo Arturo
Published: July 2002

In this work, we show that solar cells made on solar grade silicon can be improved by annealing them at high temperatures (800° C) after the aluminum at the back is evaporated. This improvement is larger for longer annealing times. Both the short circuit current (Isc) and the open circuit voltage (Voc) increase due to an increase of the base minority carrier diffusion length and a reduction of dark current, respectively. This effect may be due to "gettering" of metallic impurities and precipitates at the bulk and junction regions of the cells. For this high annealing temperature we observed that the increase of Jsc tends to saturate after 60 minutes, while Voc continues increasing for annealing times above 150 minutes.
MODELING AND ANALYSIS OF SWITCHING-MODE DC–DC REGULATORS
Authors: ALFAYYOUMI M. , NAYFEH A. H. , BOROJEVIC D.
Published: July 2002

The nonlinear dynamics of PWM DC–DC switching regulators operating in the continuous conduction mode are investigated. A quick review of the existing analysis techniques and their limitations are first presented. A discrete nonlinear time-domain model is then derived for open-loop DC–DC converters. This model is then extended for closed-loop regulator systems implementing any type of compensation scheme. The equilibrium solutions of the closed-loop system are then identified. The eigenvalues of the Jacobian matrix evaluated at the equilibrium solution are used to assess its stability. The methods developed are used to study the dynamic behavior of a DC–DC buck regulator implementing different types of compensation design: proportional, integral, proportional–integral, and proportional–integral–derivative type feedback control. A detailed bifurcation analysis of the dynamic solutions as a design or a control parameter is changed is presented. A period-doubling route to chaos is shown to exist in voltage-mode regulators, depending on the values of the parameters of the compensator and the input voltage. A further investigation of the behavior of the converter in the instability regions was carried out to improve the understanding of this interesting behavior.
UNCERTAIN CHAOTIC SYSTEM CONTROL VIA ADAPTIVE NEURAL DESIGN
Authors: GE S. S. , WANG C.
Published: July 2002

Though chaotic behaviors are exhibited in many simple nonlinear models, physical chaotic systems are much more complex and contain many types of uncertainties. This paper presents a robust adaptive neural control scheme for a class of uncertain chaotic systems in the disturbed strict-feedback form, with both unknown nonlinearities and uncertain disturbances. To cope with the two types of uncertainties, we combine backstepping methodology with adaptive neural design and nonlinear damping techniques. A smooth singularity-free adaptive neural controller is presented, where nonlinear damping terms are used to counteract the disturbances. The differentiability problem in controlling the disturbed strict-feedback system is solved without employing norm operation, which is usually used in robust control design. The proposed controllers can be applied to a large class of uncertain chaotic systems in practical situations. Simulation studies are conducted to verify the effectiveness of the scheme.
EXPERIMENTAL CHARACTERIZATION OF QUASIPERIODICITY AND CHAOS IN A MECHANICAL SYSTEM WITH DELAY
Authors: JOHNSON M. A. , MOON F. C.
Published: July 2002

We present an electro-mechanical system with finite delay whose construction was motivated by delay differential equations used to describe machine tool vibrations [Johnson, 1996; Moon & Johnson, 1998]. We show that the electro-mechanical system is capable of exhibiting periodic, quasiperiodic and chaotic vibrations. We provide a novel experimental technique for creating real-time Poincaré sections for systems with delay. This experimental technique was also applied to machine tool vibrations [Johnson, 1996]. Experimental Poincaré sections clearly show the existence of tori, and reveal the tori bifurcation sequence which leads to chaotic vibrations.

The electro-mechanical system can be modeled by a single second-order differential equation with delay and a cubic nonlinearity. We show that the simple mathematical model fully replicates the bifurcation sequence seen in the electro-mechanical system.
AN ANALYSIS ON INSTANTANEOUS STABILITY OF AN ASSOCIATIVE CHAOTIC NEURAL NETWORK
Authors: ADACHI MASAHARU , AIHARA KAZUYUKI
Published: July 2002

We analyze instantaneous stability of a chaotic neural network which shows nonperiodic associative dynamics. The network is composed of discrete-time neuron models of which individuals show chaotic dynamics with certain parameter values. The synaptic weights of the network are determined by an auto-associative matrix so that four binary patterns are stored as a basal memory of the network. It has been reported that the network retrieves stored patterns nonperiodically. However, the dynamical property of the network in each discrete-time step has not been clarified. In this paper, instantaneous stability of the network during the nonperiodic memory retrieval is analyzed by calculating eigenvalues of the Jacobian matrix. From the analysis, it is found that in every instance when the network retrieves stored patterns, all the eigenvalues are always less than unity. This implies that such states of the memory retrieval cannot be a target of the OGY-like chaos control methods.
A GEOMETRIC AND ALGEBRAIC DESCRIPTION OF ANNULAR BRAID GROUPS
Authors: KENT RICHARD P. , PEIFER DAVID
Published: July 2002

We provide a new presentation for the annular braid group. The annular braid group is known to be isomorphic to the finite type Artin group with Coxeter graph Bn. Using our presentation, we show that the annular braid group is a semidirect product of an infinite cyclic group and the affine Artin group with Coxeter graph Ãn - 1. This provides a new example of an infinite type Artin group which injects into a finite type Artin group. In fact, we show that the affine braid group with Coxeter graph Ãn - 1 injects into the braid group on n + 1 stings. Recently it has been shown that the braid groups are linear, see [3]. Therefore, this shows that the affine braid groups are also linear.
END-TO-SIDE NERVE SUTURE IN THE HUMAN PATIENT
Authors: Mennen Ulrich
Published: July 2002

End-to-side nerve suture (also called terminolateral neurorrhaphy) has been extensively examined clinically, histologically, electro-physiologically and electron microscopically in the rat and non-human primat (Chacma baboon: Papua ursinus). We have demonstrated good to excellent sensory in motor function results in the human patient for a variety of nerve injuries.

The simplicity of the procedure, the relative wide tolerance of the operative technique and the virtual consistent early recovery of both sensory and motor function, makes this method ideal for nerve injury surgery. Nerve grafts to a large extent are obviated and brachial plexus surgery gets a whole new meaning. The first 22 patients are presented.
THE ADR REPLICATION MANAGER
Authors: GALLERSDÖRFER RAINER , JARKE MATTHIAS , NICOLA MATTHIAS
Published: July 2002

ADR (Atomic Delayed Replication) is a controllable replication manager implemented on top of commercial distributed relational databases. ADR's goal is to enable various well-defined trade-offs between database coherence, throughput and response time in large database networks, e.g. for telecom applications. By combining a strategy for distributed database design with a specific replication protocol, ADR preserves the ACID properties with a controlled relaxation of coherence between primary and secondary copies. We first discuss formal characteristics of ADR, and present the implementation techniques required to realize these formal characteristics on top of commercial distributed database technology. Then, after reviewing a validated analytical performance model for the approach, we demonstrate its flexibility by summarizing experiences with two industrial ADR applications in telecommunications management, both jointly developed with Philips Laboratories. One is database support for the integrated operation and evolution of Intelligent Network telephone services, where secondary copies are held within a distributed database system optimized for throughput and availability during schema evolution. The other concerns database support for mobile phones in a City-wide DECT setting (Digital Enhanced Cordless Telecommunications), where secondary copies are held in main memory caches outside the DBMS.
GIANT OSTEOCHONDRAL LOOSE BODY OF THE KNEE JOINT
Authors: Yel Mustafa , Avunduk Mustafa Cihat , Memik Recep , Kutlu Abdurrahman
Published: July 2002

A rare giant loose body in the knee joint and the treatment carried out were reported. Two loose bodies sized 5.5 and 1.5 cm were extracted from the knee of a patient who suffered from pain and knee motion restricted chronically. The histopathological evaluation revealed normal bone, hyaline cartilaginous tissue, and partly fibrocartilaginous tissue. These loose bodies suggested that they were separated in small pieces from the femoral condyles and were nourished by the synovial fluid. Over time, they adhered to each other in the knee joint.
Credibility and Reform of Financial Institution Regulation
Authors: Stern Gary
Published: July 2002

There is heightened interest in reforming government regulation of financial institutions to make better use of market discipline and data. We strongly support such reforms, which are being implemented to some degree by the Federal Reserve System. However, market oriented reforms will not work unless government policies are credible in putting market participants, especially those at the largest financial institutions, at risk of loss. Establishing credible policies requires that governments address the time-consistency problem head-on. As a result, we recommend policies that establish credibility by directly reducing the incentive that policy-makers have to protect the creditors of financial institutions. Other policies, which do not address the fundamental reasons why policy-makers bail out creditors, are therefore likely to be circumvented when large banks get into trouble.
CAPS: a coding aid for PASM
Authors: Lumpp James E. , Fineberg Samuel A. , Casavant Thomas L. , Nation Wayne G. , Bronson Edward C. , Siegel Howard Jay , Pero Pierre H. , Marinescu Dan C. , Schwederski Thomas
Published: July 2002

Programming parallel machines is very difficult. First, generating an algorithm requires the programmer to assimilate the interactions of multiple threads of control. Second, synchronization and communication among the threads must be addressed to avoid contention and deadlock. Then, once the program is executing on the parallel system and does not function correctly or performs poorly, the debugging of multiple threads is a complicated problem [21]. Additionally, debugging software is an activity that requires systematic attention to detail. Success is a function of the experienced individual involved and the tools employed. The ability to efficiently debug software requires the wisdom to know what questions to ask, the ability to analyze the answers received, and the knowledge to formulate thebestnext question. To aid in this interactive process, the programmer needs information about the run-time behavior of the program.
Rich and lean representations of information for knowledge work
Authors: Ruhleder Karen
Published: July 2002

Applying information systems to complex intellectual tasks requires the representation and codification of ambiguous and fragmentary forms of data. This application effects changes not only in representation of this data, but in the relationships between users and tools, techniques, or systems for data interpretation. It also affects the complex infrastructures that support this process. This article uses apackagemetaphor to examine the impact on one domain of knowledge work, classical scholarship, of the “computerization” of a key data source, the textual edition. The construction of one on-line textual databank, theThesaurus Linguae Graecae(TLG), has altered the traditional relationships between text “owners” and “users” has changed the role of the text as a conduit for social and historical information, and has disrupted traditional patterns of transmitting domain expertise. A rich information resource has become lean in its electronic form.

The TLG has standardized the corpus of Greek literature and eased access to a broad range of works, including rare and out-of-print materials. At the same time, its construction has decoupled often-contested textual sources from their accompanying critical notes and supplemental materials. The use of the TLG has also shifted notions of objectivity, accuracy, and requisite expertise within the community. The transmission of domain knowledge must now be coupled with the transmission of technical knowledge, a process for which no infrastructure is currently in place. These experiences parallel those of other knowledge workers. “Mechanistic” paradigms of information and knowledge cannot accommodate important components of computing packages, including the transmission of expertise and infrastructures for tool development and evaluation. Recent developments in information storage and dissemination, including gophers and ftp sites may indicate that despite technical advances that could be used to support rich representations (such as hypermedia and multimedia), leaner forms of data may prevail.
Geometric range searching
Authors: Matoušek Jiří
Published: July 2002

In geometric range searching, algorithmic problems of the following type are considered. Given ann-point set P in the plane, build a data structure so that, given a query triangle R, the number of points of P lying in R can be determined quickly. Similar questions can be asked for point sets in higher dimensions, with triangles replaced by simplices or by more complicated shapes. Algorithms of this type are of crucial importance in computational geometry, as they can be used as subroutines in solutions to many seemingly unrelated problems, which are often motivated by practical applications, for instance in computer graphics (ray tracing, hidden-surface removal etc.). We present a survey of theoretical results and the main techniques in geometric range searching.
A data-level parallel linear-quadratic penalty algorithm for multicommodity network flows
Authors: Pinar Mustafa Ç. , Zenios Stavros A.
Published: July 2002

We describe the development of a data-level, massively parallel, software system for the solution of multicommodity network flow problems. Using a smooth linear-quadratic penalty (LQP) algorithm we transform the multicommodity network flow problem into a sequence of independent min-cost network flow subproblems. The solution of these problems is coordinated via a simple, dense, nonlinear master program to obtain a solution that is feasible within some user-specified tolerance to the original multicommodity network flow problem. Particular emphasis is placed on the mapping of both the subproblems and master problem data to the processing elements of a massively parallel computer, the Connection Machine CM-2. As a result of this design we can solve large and sparse optimization problems on current SIMD massively parallel architectures. Details of the implementation are reported, together with summary computational results with a set of test problems drawn from a Military Airlift Command application.
Women in computing
Authors: Pearl Amy
Published: July 2002

The world is changing and the demographics of the workforce are changing with it. At one time there was hope that our exciting new field of computer science would not only revolutionize the technical world in which we live, but break new ground in professional access and equity for women. This optimism has given way to pragmatism. If we want the best and the brightest women to participate fully in our profession, we must take a long hard look at our professional practices and conventions. The goal of this special section is to provide computer professionals with the information to understand the issues that women confront in their workplace and with the resources to successfully diversify their workplace. I hope you will save this issue of
Communications
as a reference for many years to come. I also hope that, as opportunities for women in computer science expand, the need for the specialized resources and programs we described here diminishes.
Visualizing real-time multivariate data using preattentive processing
Authors: Healey Christopher G. , Booth Kellogg S. , Enns James T.
Published: July 2002

A new method is presented for visualizing data as they are generated from real-time applications. These techniques allow viewers to perform simple data analysis tasks such as detection of data groups and boundaries, target detection, and estimation. The goal is to do this rapidly and accurately on a dynamic sequence of data frames. Our techniques take advantage of an ability of the human visual system called preattentive processing. Preattentive processing refers to an initial organization of the visual system based on operations believed to be rapid, automatic, and spatially parallel. Examples of visual features that can be detected in this way include hue, orientation, intensity, size, curvature, and line length. We believe that studies from preattentive processing should be used to assist in the design of visualization tools, especially those for which high speed target, boundary, and region detection are important. Previous work has shown that results from research in preattentive processing can be used to build visualization tools that allow rapid and accurate analysis of individual, static data frames. We extend these techniques to a dynamic real-time environment. This allows users to perform similar tasks on dynamic sequences of frames, exactly like those generated by real-time systems such as visual interactive simulation. We studied two known preattentive features, hue and curvature. The primary question investigated was whether rapid and accurate target and boundary detection in dynamic sequences is possible using these features. Behavioral experiments were run that simulated displays from our preattentive visualization tools. Analysis of the results of the experiments showed that rapid and accurate target and boundary detection is possible with both hue and curvature. A second question, whether interactions occur between the two features in a real-time environment, was answered positively.
Algorithm 760: Rectangular-grid-data surface fitting that has the accuracy of a bicubic polynomial
Authors: Akima Hiroshi
Published: July 2002

A local algorithm for smooth surface fitting for rectangular-grid data has been presented. It has the accuracy of a bicubic polynomial.
The meaning of negative premises in transition system specifications
Authors: Bol Roland , Groote Jan Friso
Published: July 2002

We present a general theory for the use of negative premises in the rules of Transition System Specifications (TSSs). We formulate a criterion that should be satisfied by a TSS in order to be meaningful, that is, to unequivocally define a transition relation. We also provide powerful techniques for proving that a TSS satisfies this criterion, meanwhile constructing this transition relation. Both the criterion and the techniques originate from logic programming [van Gelder et al. 1988; Gelfond and Lifschitz 1988] to which TSSs are close. In an appendix we provide an extensive comparison between them.

As in Groote [1993], we show that the bisimulation relation induced by a TSS is a congruence, provided that it is inntyft/ntyxt-format and can be proved meaningful using our techniques. We also considerably extend the conservativity theorems of Groote[1993] and Groote and Vaandrager [1992]. As a running example, we study the combined addition of priorities and abstraction to Basic Process Algebra (BPA). Under some reasonable conditions we show that this TSS is indeed meaningful, which could not be shown by other methods [Bloom et al. 1995; Groote 1993]. Finally, we provide a sound and complete axiomatization for this example.
Concurrency versus availability: atomicity mechanisms for replicated data
Authors: Herlihy Maurice
Published: July 2002

A replicated object is a typed data object that is stored redundantly at multiple locations to enhance availability. Most techniques for managing replicated data have a two-level structure: At the higher level, a replica-control protocol reconstructs the object's state from its distributed components, and at the lower level, a standard concurrency-control protocol synchronizes accesses to the individual components. This paper explores an alternative approach to managing replicated data by presenting two replication methods in which concurrency control and replica management are handled by a single integrated protocol. These integrated protocols permit more concurrency than independent protocols, and they allow availability and concurrency to be traded off: Constraints on concurrency may be relaxed if constraints on availability are tightened, and vice versa. In general, constraints on concurrency and availability cannot be minimized simultaneously.
Layout-driven RTL binding techniques for high-level synthesis using accurate estimators
Authors: Xu Min , Kurdahi Fadi J.
Published: July 2002

The importance of effective and efficient accounting of layout effects is well established in High-Level Synthesis (HLS), since it allows more realistic exploration of the design space and the generation of solutions with predictable metrics. This feature is highly desirable in order to avoid unnecessary iterations through the design process. In this article, we address the problem of layout-driven register-transfer-level (RTL) binding as this step has a direct relevance to the final performance of the design. By producing not only an RTL design but also an approximate physical topology of the chip-level implementation, we ensure that the solution will perform at the predicted metric once implemented, thus avoiding unnecessary delays in the design process.
Optimization of Static Loading and Sizing of Multilevel Memory Systems
Authors: Arora S. R. , Gallo A.
Published: July 2002

The following two important aspects of multilevel static memory management are treated: (1) memory loading, and (2) memory sizing. An algorithm is developed for the optimal loading of program and data files in various memory levels of given sizes. The selection of optimal sizes from a given set of finite alternatives is done through a cyclic queueing model, which recognizes the effects of queues and waiting times and helps in deriving a balanced system.
Simulating Stable Stochastic Systems, I: General Multiserver Queues
Authors: Crane Michael A. , Iglehart Donald L.
Published: July 2002

A technique is introduced for analyzing simulations of stochastic systems in the steady state. From the viewpoint of classical statistics, questions of simulation run duration and of starting and stopping simulations are addressed. This is possible because of the existence of a random grouping of observations which produces independent identically distributed blocks from the start of the simulation. The analysis is presented in the context of the general multiserver queue, with arbitrarily distributed interarrival and service times. In this case, it is the busy period structure of the system which produces the grouping mentioned above. Numerical illustrations are given for the M/M/1 queue. Statistical methods are employed so as to obtain confidence intervals for a variety of parameters of interest, such as the expected value of the stationary customer waiting time, the expected value of a function of the stationary waiting time, the expected number of customers served and length of a busy cycle, the tail of the stationary waiting time distribution, and the standard deviation of the stationary waiting time. Consideration is also given to determining system sensitivity to errors and uncertainty in the input parameters.
The Parallel Evaluation of General Arithmetic Expressions
Authors: Brent Richard P.
Published: July 2002

It is shown that arithmetic expressions with
n
≥ 1 variables and constants; operations of addition, multiplication, and division; and any depth of parenthesis nesting can be evaluated in time 4 log
2
n
+ 10(
n
- 1)/
p
using
p
≥ 1 processors which can independently perform arithmetic operations in unit time. This bound is within a constant factor of the best possible. A sharper result is given for expressions without the division operation, and the question of numerical stability is discussed.
A Combinatorial Problem Related to Multimodule Memory Organizations
Authors: Wong C. K. , Coppersmith Don
Published: July 2002

This paper deals with a combinatorial minimization problem arising from studies on multimodule memory organizations. Instead of searching for an optimum solution, a particular solution is proposed and it is demonstrated that it is close to optimum. Lower bounds for the objective functions are obtained and compared with the corresponding values of the particular solution. The maximum percentage deviation of this solution from optimum is also established.
Testing Deadlock-Freedom of Computer Systems
Authors: Kameda Tiko
Published: July 2002

The problem of determining whether it is possible for a set of “free-running” processes to become deadlocked is considered. It is assumed that any request by a process is immediately granted as long as there are enough free resource units to satisfy the request. The question of whether or not there exists a polynomial algorithm for predicting deadlock in a “claim-limited” serially reusable resource system has been open. An algorithm employing a network flow technique is presented for this purpose. Its running time is bounded byO(mn1.5) if the system consists ofnprocesses sharingmtypes of serially reusable resources.
Efficient optimistic parallel simulations using reverse computation
Authors: Carothers Christopher D. , Perumalla Kalyan S. , Fujimoto Richard M.
Published: July 2002

In optimistic parallel simulations, state-saving techniques have traditionally been used to realize rollback. In this article, we propose
reverse computation
as an alternative approach, and compare its execution performance against that of state-saving. Using compiler techniques, we describe an approach to automatically generate reversible computations, and to optimize them to reap the performance benefits of reverse computation transparently. For certain fine-grain models, such as queuing network models, we show that reverse computation can yield significant improvement in execution speed coupled with significant reduction in memory utilization, as compared to traditional state-saving. On sample models using reverse computation, we observe as much as a six-fold improvement in execution speed over traditional state-saving.
Algorithm 800
Authors: Benner Peter , Byers Ralph , Barth Eric
Published: July 2002

This article describes LAPACK-based Fortran 77 subroutines for the reduction of a Hamiltonian matrix to square-reduced form and the approximation of all its eigenvalues using the implicit version of Van Loan's method. The transformation of the Hamiltonian matrix to a square-reduced form transforms a Hamiltonian eigenvalue problem of order 2
n
to a Hessenberg eigenvalue problem of order
n
. The eigenvalues of the Hamiltonian matrix are the square roots of those of the Hessenberg matrix. Symplectic scaling and norm scaling are provided, which, in some cases, improve the accuracy of the computed eigenvalues. We demonstrate the performance of the subroutines for several examples and show how they can be used to solve some control-theoretic problems.
Confidence intervals using orthonormally weighted standardized time series
Authors: Foley Robert D. , Goldsman David
Published: July 2002

We extend the standardized time series area method for constructing confidence intervals for the mean of a stationary stochastic process. The proposed intervals are based on orthonormally weighted standardized time series area variance estimators. The underlying area estimators possess two important properties: they are first-order unbiased, and they are asymptotically independent of each other. These properties are largely the result of a careful choice of weighting functions, which we explicitly describe. The asymptotic independence of the area estimators yields more degrees of freedom than various predecessors; this, in turn, produces smaller mean and variance of the length of the resulting confidence intervals. We illustrate the efficacy of the new procedure via exact and Monte Carlo examples. We also provide suggestions for efficient implementation of the method.
Bootstrap confidence intervals for ratios of expectations
Authors: Choquet Denis , L'Ecuyer Pierre , Léger Christian
Published: July 2002

We are concerned with computing a confidence interval for the ratioE[Y]/E[X, where (X,Y) is a pair of random variables. This ratio estimation problem arises in, for instance, regenerative simulation. As an alternative to confidence intervals based on asymptotic normality, we study and compare different variants of the bootstrap for one-sided and two-sided intervals. We point out situations where these techniques provide confidence intervals with coverage much closer to the nominal value than do the classical methods.
General considerations on the design of an interactive system for data analysis
Authors: Ling Robert F.
Published: July 2002

Among the most important criteria in the design and implementation of an interactive system for data analysis are: data structure, control language, user interface, sytem versatility, extensibility, and portability. The design of an interactive system, viewed as a set of constrained decisions based on these criteria, will be discussed. The concepts and considerations discussed in this article about the design of interactive systems are general in nature and are neither problem-specific nor discipline-specific. Specific examples from statistical packages and their designs are cited for illustration purposes only.
An updated survey of GA-based multiobjective optimization techniques
Authors: Coello Carlos A.
Published: July 2002

After using evolutionary techniques for single-objective optimization during more than two decades, the incorporation of more than one objective in the fitness function has finally become a popular area of research. As a consequence, many new evolutionary-based approaches and variations of existing techniques have recently been published in the technical literature. The purpose of this paper is to summarize and organize the information on these current approaches, emphasizing the importance of analyzing the operations research techniques in which most of them are based, in an attempt to motivate researchers to look into these mathematical programming approaches for new ways of exploiting the search capabilities of evolutionary algorithms. Furthermore, a summary of the main algorithms behind these approaches is provided, together with a brief criticism that includes their advantages and disadvantages, degree of applicability, and some known applications. Finally, further trends in this area and some possible paths for further research are also addressed.
Models for parallel processing within programs
Authors: Towsley D. , Chandy K. M. , Browne J. C.
Published: July 2002

Approximate queueing models for internal parallel processing by individual programs in a multiprogrammed system are developed in this paper. The solution technique is developed by network decomposition. The models are formulated in terms of CPU:I/O and I/O:I/O overlap and applied to the analysis of these problems. The percentage performance improvement from CPU:I/O overlap is found to be greatest for systems which are in approximate CPU:I/O utilization balance and for low degrees of multiprogramming. The percentage improvement from I/O:I/O overlap is found to be greatest for systems in which the I/O system is more utilized than the CPU.
A model of memory contention in a paging machine
Authors: Oden P. H. , Shedler G. S.
Published: July 2002

This paper is concerned with certain aspects of contention for main memory resources in a multiprogrammed computer system operating under demand paging. In the model presented, the number of page-frames of main memory allocated to a problem program varies in time. These changes in memory configuration are represented explicitly in the model, CPU requirements and page exception characteristics of program material being described statistically. Expressions for the distribution of the number of page-frames allocated to an executing program, the long run expected fraction of a program's execution time in a given number of page-frames, and the average execution interval of the multi-programmed load are obtained. It is pointed out heuristically and demonstrated numerically that an increase is obtainable in the average execution interval of the multiprogrammed load over that resulting from equal fixed partitioning of main memory.
Spelling correction in systems programs
Authors: Morgan Howard L.
Published: July 2002

Several specialized techniques are shown for efficiently incorporating spelling correction algorithms into compilers and operating systems. These include the use of syntax and semantics information, the organization of restricted keyword and symbol tables, and the consideration of a limited class of spelling errors. Sample 360 coding for performing spelling correction is presented. By using systems which perform spelling correction, the number of debugging runs per program has been decreased, saving both programmer and machine time.
Variable-width tables with binary-search facility
Authors: Halpern Mark
Published: July 2002

The family of subroutines described in this report was designed to create, search and maintain tables which are to contain entries of different lengths, and yet be amenable to search by partition, or “binary” search. It is designed explicitly for fixed-word-length binary machines; the tables in question are the argument-function type, with the two parts physically separated—i.e., no one machine word contains both, or parts of both. The family consists at present of seven subroutines, of which four are primitive and three second-generation. (By “primitive” is meant a self-sufficient routine; a second-generation routine is one which calls on one or more primitives.) These routines are at present coded for the IBM 709; with a few trivial changes they are ready also for the 704. The primitives are: (1) STT (Start Table), (2) TLU (Table Look-Up), (3) ITC (Increase Table Capacity), and (4) AOD (Append Ordered Data). The second-generation routines are: (1) INT (Insert in Table), (2) INX (Insert and Expand), and (3) ANX (Append and Expand). It is intended that this family be written, with modifications as necessary, for several stored-program computers. The calling-sequences for any one of the routines will, as far as possible, be identical on the several machines.
Estimation of parameters and eigenmodes of multivariate autoregressive models
Authors: Neumaier Arnold , Schneider Tapio
Published: July 2002

Dynamical characteristics of a complex system can often be inferred from analysis of a stochastic time series model fitted to observations of the system. Oscillations in geophysical systems, for example, are sometimes characterized by principal oscillation patterns, eigenmodes of estimated autoregressive (AR) models of first order. This paper describes the estimation of eigenmodes of AR models of arbitrary order. AR processes of any order can be decomposed into eigenmodes with characteristic oscillation periods, damping times, and excitations. Estimated eigenmodes and confidence intervals for the eigenmodes and their oscillation periods and damping times can be computed from estimated models parameters. As a computationally efficient method of estimating the parameters of AR models from high-dimensional data, a stepwise least squares algorithm is proposed. This algorithm computes models of successively decreasing order. Numerical simulations indicate that, with the least squares algorithm, the AR model coefficients and the eigenmodes derived from the coefficients and eigenmodes are rough approximations of the confidence intervals inferred from the simulaitons.