bluuebunny/crossref_metadata_2025 huggingface dataset:
RARE GAS PRECIPITATES IN METALS AS QUANTUM DOTS FOR THE POLARITONS
Authors: GOLINEY IGOR , SUGAKOV VOLODYMYR
Published: July 2002

Energy spectra of the size quantization of excitons in Xe, Kr, Ar and Ne precipitates in Al and their manifestation in reflection spectra are calculated taking into account polariton effects (dipole-dipole exciton interactions), spatial dispersion and mixing of the electronic excitations of the inclusion with collective excitations of the surrounding metal (plasmons). It was shown that: 1) the proximity of energies of the exciton levels and the plasmons localized on the inclusion (surface plasmons) results in the gigantic shift (up to 1 eV) of the levels of coupled excitations, 2) the transfer of the oscillator strength from the plasmon level to the exciton levels leads to the amplification of optical transitions in bubbles by several orders of magnitude. Depending on the position of the surface polariton with respect to the surface plasmon the spectra either show additional broadenning due to the coupling with quantized exciton levels (Ar, Ne) or the polariton level is pushed out of the exciton band and manifests itself as a narrow dip in the reflection spectra.
A STUDY OF CHROMIUM ON WETTABILITY OF LIQUID COPPER ON ALUMINA CERAMICS
Authors: ZHANG J. X. , CHANDEL R. S. , SEOW H. P.
Published: July 2002

The wetting characteristics of metals on ceramics is an important factor of many processes such as brazing, bonding, liquid-phase sintering of infiltrating when metals and ceramics are needed to be combined together. However, most of the pure metals exhibit obtuse contact angles on ceramics and thus some addition of active metals are required to enhance their wettability. In this study, the effect and role of an active element such as chromium has been evaluated as an additive to promote the wetting of liquid copper on alumina by a sessile drop method. It is found that an appropriate percent of chromium addition can improve the wettability of copper on alumina after a long exposure at high temperature. According to SEM observation, chromium inclines to segregating in the interface area between solidified copper droplet and alumina substrate. In order to further understand the modification mechanism of chromium, XRDand TEM are performed to identify the created phases and analyze the reactions in the interface. Finally, a model for chromium effect on the reactive wetting is proposed.
A Novel Mechanism of Electrorheological Effect in Polymer Blends
Authors: Kito H. , Tajiri K. , Orihara H. , Ishibashi Y. , Doi M. , Inoue A.
Published: July 2002

We present a novel mechanism of an electrorheological (ER) effect found in a polymer blend of a liquid crystalline polymer (LCP) with high viscosity and a polydimethylsiloxane (DMS) with low viscosity. In this type of ER fluid thin layers of DMS are formed between the parallel plates of a viscometer and so the blends separated by them can slide on each other, resulting in the decrease of the apparent viscosity. Under an electric field, on the other hand, the area of the layers decreases and thus the ER effect appears.
PWM Flow Rate Control of ER Valve and its Application to ER Actuator Control
Authors: Nakano Masami , Minagawa Shuji , Hagino Katsuya
Published: July 2002

The PWM (Pulse Width Modulation) control of ER valve consisting of two parallel electrodes has been investigated to continuously control the flow rate of an electrorheological (ER) suspension containing sulfonated polymer particles in silicone oil. PWM wave voltages are applied to the electrodes of the ER valve. It is possible to control continuously the flow rate by changing the duty ratio of the PWM wave from 1 to 0, where the duty ratio of 1 corresponds to the state to stop the flow.

A miniature bellows actuator driven by a pair of PWM controlled ER valves has been developed, and the control characteristics of the actuator have been investigated. The duty ratios of both ER valves have been proposed to be changed alternately in proportion to the control voltage V to control the flow rate into and out of the bellows chamber, and also an overlap duty ratio D ov at V=0V has been introduced. The introduction of the overlap duty ratio D ov was found to be very important to smoothly control the actuator and to improve the control performance.
1/8 PROBLEMS IN THE La-, Bi- AND Y-BASED CUPRATES AND NEW ANOMALIES IN THE OVERDOPED REGION OF THE La-BASED CUPRATE
Authors: KOIKE Y. , AKOSHIMA M. , ADACHI T. , KAKINUMA N. , NOJI T. , ONO Y. , NISHIZAKI T. , KOBAYASHI N. , WATANABE I. , NAGAMINE K.
Published: July 2002

Recent experimental work on the 1/8 problem by our group is reviewed not only in the La-based cuprate but also in the Bi- and Y-based ones. In the partially Zn-substituted Bi 2 Sr 2 Ca 1-x Y x( Cu 1-y Zn y)2 O 8+δ, we have found anomalous suppression of superconductivity at x=0.30-0.35, where the hole concentration per Cu p~1/8. Moreover, it has been revealed from the μSR measurements that the Cu-spin fluctuations exhibit slowing-down behavior at low temperatures in these samples. These results are suggestive of the stripe correlations of holes and spins tending to be pinned by Zn at p~1/8 in the Bi-nbased cuprate as well as in the La-based cuprate. In Y 1-x Ca x Ba 2 Cu 3 O 7-δ, the 60 K plateau of Tc has been found not to be correlated with the oxygen content but to be interpreted as being due to the suppression of superconductivity at p~1/8. Accordingly, we conclude that the 1/8 problem is common to all high-Tc cuprates with the CuO 2 plane. Moreover, we have found transport and Tc anomalies around x=0.22 in La 2-x Sr x Cu 1-y M y O 4 ( M = Zn , Ga), suggesting a possibility that an order of holes and/or spins is formed or fluctuates in these samples in the overdoped region.
INFLUENCE OF TECHNOLOGICAL PARAMETERS ON THE QUALITY OF THE Bi-BASED SUPERCONDUCTORS
Authors: SMRČKOVÁ O. , SÝKOROVÁ D. , PETRÝDES D. , VAŠEK P.
Published: July 2002

The effect of the sintering temperature, the cooling rate and the additive on the critical parameters was studied on samples with nominal composition Bi 1.8( Pb 0.26) Sr 2 Ca 2 Cu 3 O 8+x both undoped and with addition of 5, 9, 12.7 mol % of boron (as B 2 O 3), respectively. The sample with 5 mol % of boron cooled slowly had the critical current density five times higher than undoped sample. The rapid cooling of the samples caused enhancement of the volume of the 2223 phase.
MAGNETIC BEHAVIOR OF LEAD-BISMUTATE GLASSES CONTAINING TRANSITION METAL ELEMENTS
Authors: POP R. , SIMON V. , COSMA I. , COLDEA M.
Published: July 2002

The investigated samples are obtained by adding to the 3Bi2O3·2PbO glass matrix the transition metal oxides Fe2O3 or MnO up to 20 mol%. The temperature dependencies of the magnetic susceptibility evidence negative paramagnetic Curie temperatures suggesting the antiferromagnetic nature of the magnetic interaction between the transition metal (TM) ions in the samples studied. According to the magnetic moment values, calculated from the experimental data, the valence state of the iron ions changes from Fe 3+ to Fe 2+ and that of manganese ions from Mn 2+ to Mn 3+ as the concentration x increases from 1 to 20 mol%.
LOW-COMPLEXITY CHARACTER EXTRACTION IN LOW-CONTRAST SCENE IMAGES
Authors: WINGER LOWELL L. , ROBINSON JOHN A. , JERNIGAN M. ED
Published: July 2002

There is wide application for the extraction of textual information from low-contrast, complex natural images. We are particularly interested in segmentation and thresholding algorithms for use in a portable text-to-speech system for the vision impaired. Reading low-contrast LCD displays is the target application. We present a low-complexity method for automatically extracting text of any size, font, and format from images acquired by a video camera that may be poorly focused and aimed, under conditions of inadequate and uneven illumination. The new method consists of fast thresholding that combines a local variance measure with a logical stroke-width method, and with a low-complexity statistical and contextual noise segmentation. The performance of this method compares favorably with more complex methods for the extraction of characters from scene images. Initial results are encouraging for application in a robust portable reader.
CHAOTIC MASKING WITHOUT SYNCHRONIZATION
Authors: RYABOV V. B. , USIK P. V. , VAVRIV D. M.
Published: July 2002

A method of secure communication based on the inversion of a chaotic dynamical system is analyzed. The approach does not require chaotic synchronization of two or several oscillators to be used. The influence of noise in the communication channel and parameter mismatch on the quality of decoded signal is discussed. The feasibility of the approach is demonstrated by the examples of nonautonomous pendulum equation and autonomous Rössler oscillator.
TRANSITION TO CHAOTIC ROTATING WAVES IN ARRAYS OF COUPLED LORENZ OSCILLATORS
Authors: SÁNCHEZ E. , MATÍAS M. A.
Published: July 2002

In the present paper we report experimental observations of discrete spatiotemporal structures in rings of unidirectionally coupled analog Lorenz systems. This is an extension of the results previously reported in [Sánchez & Matías, 1998], studying now other parameter regimes. These studies are based on the use of an analog circuit corresponding to Lorenz equations. The more interesting new result is that a route has been found connecting periodic and chaotic rotating waves in a new kind of transition involving two symmetry related quasiperiodic attractors that merge at the transition point.
Mutually braided links, films and exchangeability
Authors: Rampichini M.
Published: July 2002

Two links A, B (where A is the unknot) are exchangeable if B is a braid rel A, and also A is a (generalized) braid rel B. If moreover A, B are mutually braided in the sense of Rudolph, i.e. their fibres meet in a particularly nice way, the whole situation can be described by a finite collection of combinatorial data, that I call a film. In this paper is proven that a film can be associated to each pair of mutually braided links, and that from a film it is always possible to reconstruct (uniquely up to isotopy) the whole situation of the pair of fibrations of two mutually braided links. Using this new tool, it is proven that exchangeable links are in fact mutually braided.
STRONGLY ALMOST TRIVIAL θ-CURVES
Authors: HUH YOUNGSIK , JIN GYO TAEK , OH SEUNGSANG
Published: July 2002

A θ-curve is called almost trivial if it does not contain any non-trivial knot. A θ-curve is called strongly almost trivial if it has a planar projection which does not contain a projection of any non-trivial knot. In this paper, we introduce a method to present strongly almost trivial θ-curves. We also give an almost trivial θ-curve which may not be strongly almost trivial.
SATELLITE GRAVITATIONAL ORBITAL PERTURBATIONS AND THE GRAVITOMAGNETIC CLOCK EFFECT
Authors: IORIO LORENZO
Published: July 2002

In order to detect the gravitomagnetic clock effect by means of two counter-orbiting satellites placed on identical equatorial and circular orbits around the Earth with radius 7000 km their radial and azimuthal positions must be known with an accuracy of δr=10-1 mm and δϕ=10-2 mas (milliarcseconds) per revolution. In this work we investigate if the radial and azimuthal perturbations induced by the dynamical and static parts of the Earth's gravitational field meet these requirements. While the radial direction is affected only by harmonic perturbations with periods up to some tens of days, the azimuthal location is perturbed by a secular drift and very long period effects. It results that the present level of accuracy in the knowledge both of the Earth solid and ocean tides, and of the static part of the geopotential does not allow an easy detection of the gravitomagnetic clock effect at least by using short arcs only.
PERIODIC HARTREE–FOCK CALCULATION OF THE OXIDATION OF Si(111)
Authors: SONNET PHILIPPE , STAUFFER LOUISE , MINOT CHRISTIAN
Published: July 2002

We present Hartree–Fock calculations of the adsorption of oxygen on a Si(111)-(2×2) surface, which models the Si(111)-(7×7) structure, including its two main sites (adatom and rest atom sites). In the most stable configurations, molecules dissociate leading to atomic oxygen bridging the adatom backbonds. The molecular adsorption is less favorable. The dioxygen, however, is a local minimum of the potential surface in two cases: (i) in the "grif" geometry; (ii) bridging between a rest atom and an adatom. It then represents a possible precursor for the early stage of oxidation. The presence of an oxygen atom already adsorbed on the surface enhances the heat of adsorption of other oxygen (atomic or molecular) on the same site.
A DYNAMIC GAME OF OFFENDING AND LAW ENFORCEMENT
Authors: FENT THOMAS , FEICHTINGER GUSTAV , TRAGLER GERNOT
Published: July 2002

In this paper, we analyse a differential game describing the interactions between a potential offender and the law enforcement agency. We assume that both players want to maximise their welfare expressed in monetary units, and compare the results obtained by applying the Nash equilibrium concept under symmetric with that under asymmetric information. The comparison reveals that under asymmetric information the offence rate is lower, due to the deterrence caused by the activities of the law enforcement agency. Both players' controls start at a steady state value and stick to it until close to the end of the planning horizon, when they leave the steady state to take into account the scrap value; this can be interpreted as a turnpike property of Nash equilibria. Furthermore, a sensitivity analysis is carried out. Among others, it turns out that a myopic offender tends to a higher offence level.
OPTIMAL PAYOFF FUNCTIONS FOR MEMBERS OF COLLECTIVES
Authors: WOLPERT DAVID H. , TUMER KAGAN
Published: July 2002

We consider the problem of designing (perhaps massively distributed) collectives of computational processes to maximize a provided "world utility" function. We consider this problem when the behavior of each process in the collective can be cast as striving to maximize its own payoff utility function. For such cases the central design issue is how to initialize/update those payoff utility functions of the individual processes so as to induce behavior of the entire collective having good values of the world utility. Traditional "team game" approaches to this problem simply assign to each process the world utility as its payoff utility function. In previous work we used the "Collective Intelligence" (COIN) framework to derive a better choice of payoff utility functions, one that results in world utility performance up to orders of magnitude superior to that ensuing from the use of the team game utility. In this paper, we extend these results using a novel mathematical framework. Under that new framework we review the derivation of the general class of payoff utility functions that both (i) are easy for the individual processes to try to maximize, and (ii) have the property that if good values of them are achieved, then we are assured a high value of world utility. These are the "Aristocrat Utility" and a new variant of the "Wonderful Life Utility" that was introduced in the previous COIN work. We demonstrate experimentally that using these new utility functions can result in significantly improved performance over that of previously investigated COIN payoff utilities, over and above those previous utilities' superiority to the conventional team game utility. These results also illustrate the substantial superiority of these payoff functions to perhaps the most natural version of the economics technique of "endogenizing externalities."
The Dynamics of Specialization and Generalization within Biological Populations
Authors: Spencer Andrew J. , Couzin Iain D. , Franks Nigel R.
Published: July 2002

We develop an abstract model to explore specialization and generalization in task performance by individuals within biological populations. Individuals follow simple rules of increasing and decreasing task propensities that could, for example, be based on learning and forgetting. The model does not explore efficiency per se, but makes the prediction that where behavioural specialization occurs in nature, organisms, are likely to be reaping sufficient benefits from improved handling efficiency to offset the costs of increased search time. A second prediction is that among specialists, there will be a trade-off between stability and responsiveness. The model reveals potential similarities between a wide range of complex biological systems.
Log on education
Authors: Soloway Elliot
Published: July 2002

History has dealt computer and information science a special role in the inevitable restructuring of the educational system in the United States. In the coming decade computing and information technology will be the backbone of the most significant change in education in over 100 years. Rather than being an adjunct to learning and teaching, technology is facilitating a fundamental re-thinking of what should be learned and how. Such changes present the
Communications
readership with a unique opportunity and a serious responsibility. Toward meeting this challenge, in this column I will address some key issues in education and technology. For example, this first column examines how our basic notion of what needs to be learned is changing, and how this affects the ways in which technology is used. Subsequent columns will explore topics such as “programming's role in learning,” “multi-media, and nationwide, computer-based,” testing.
Computers, ethics, and values
Authors: Neumann Peter G.
Published: July 2002

Comdex in Las Vegas is the largest North American trade show for personal computer users. The show, which is vast, provided me with many impressions. I jotted many of these in my notebook and will share some of them with you here.
Unexpected side effects of inline substitution
Authors: Cooper Keith D. , Hall Mary W. , Torczon Linda
Published: July 2002

The structure of a program can encode implicit information that changes both the shape and speed of the generated code. Interprocedural transformations like inlining often discard such information; using interprocedural data-flow information as a basis for optimization can have the same effect.

In the course of a study on inline substitution with commercial FORTRAN compilers, we encountered unexpected performance problems in one of the programs. This paper describes the specific problem that we encountered, explores its origins, and examines the ability of several analytical techniques to help the compiler avoid similar problems.
Offices are open systems
Authors: Hewitt Carl
Published: July 2002

This paper is intended as a contribution to analysis of the implications of viewing offices as open systems. It takes a prescriptive stance on how to establish the information-processing foundations for taking action and making decisions in office work from an open systems perspective. We propose
due process
as a central activity in organizational information processing. Computer systems are beginning to play important roles in mediating the ongoing activities of organizations. We expect that these roles will gradually increase in importance as computer systems take on more of the authority and responsibility for ongoing activities. At the same time we expect computer systems to acquire more of the characteristics and structure of human organizations.
Design rules based on analyses of human error
Authors: Norman Donald A.
Published: July 2002

By analyzing the classes of errors that people make with systems, it is possible to develop principles of system design that minimize both the occurrence of error and the effects. This paper demonstrates some of these principles through the analysis of one class of errors: slips of action. Slips are defined to be situations in which the user's intention was proper, but the results did not conform to that intention. Many properties of existing systems are conducive to slips; from the classification of these errors, some procedures to minimize the occurrence of slips are developed.
The GOMS family of user interface analysis techniques
Authors: John Bonnie E. , Kieras David E.
Published: July 2002

Sine the publication ofThe Psychology of Human-Computer Interaction, the GOMS model has been one of the most widely known theoretical concepts in HCI. This concept has produced severval GOMS analysis techniques that differ in appearance and form, underlying architectural assumptions, and predictive power. This article compares and contrasts four popular variantsof the GOMS family (the Keystroke-Level Model, the original GOMS formulation, NGOMSL, and CPM-GOMS) by applying them to a single task example.
Disk-directed I/O for MIMD multiprocessors
Authors: Kotz David
Published: July 2002

Many scientific applications that run on today's multiprocessors, such as weather forecasting and seismic analysis, are bottlenecked by their file-I/O needs. Even if the multiprocessor is configured with sufficient I/O hardware, the file system software often fails to provide the available bandwidth to the application. Although libraries and enhanced file system interfaces can make a significant improvement, we believe that fundamental changes are needed in the file server software. We propose a new technique, disk-directed I/O, to allow the disk servers to determine the flow of data for maximum performance. Our simulations show that tremendous performance gains are possible both for simple reads and writes and for an out-of-core application. Indeed, our disk-directed I/O technique provided consistent high performance that was largely independent of data distribution and obtained up to 93% of peak disk bandwidth. It was as much as 18 times faster than either a typical parallel file system or a two-phase-I/O library.
Fault-tolerant wait-free shared objects
Authors: Jayanti Prasad , Chandra Tushar Deepak , Toueg Sam
Published: July 2002

Wait-free implementations of shared objects tolerate the failure of processes, but not the failure of base objects from which they are implemented. We consider the problem of implementing shared objects that tolerate the failure of both processes and base objects.

We identify two classes of object failures:responsiveandnonresponsive. With responsive failures, a faulty object responds to every operation, but its responses may be incorrect. With nonresponsive failures, a faulty object may also “hang” without responding. In each class, we definecrash, omission,andarbitrarymodes of failure.

We show that all responsive failure modes can be tolerated. More precisely, for all responsive failure modes ℱ, object typesT, andt≥ 0, we show how to implement a shared object of typeTwhich ist-tolerant for ℱ. Such an object remains correct and wait-free even if up totbase objects fail according to ℱ. In contrast to responsive failures, we show that even the most benign non-responsive failure mode cannot be tolerated. We also show that randomization can be used to circumvent this impossibility result.

Graceful degradationis a desirable property of fault-tolerant implementations: the implemented object never fails more severely than the base objects it is derived from, even if all the base objects fail. For several failure modes, we show wheter this property can be achieved, and, if so, how.
A combined unifrontal/multifrontal method for unsymmetric sparse matrices
Authors: Davis Timothy A. , Duff Iain S.
Published: July 2002

We discuss the organization of frontal matrices in multifrontal methods for the solution of large sparse sets of unsymmetric linear equations. In the multifrontal method, work on a frontal matrix can be suspended, the frontal matrix can be stored for later reuse, and a new frontal matrix can be generated. There are thus several frontal matrices stored during the factorization, and one or more of these are assembled (summed) when creating a new frontal matrix. Although this means that arbitrary sparsity patterns can be handled efficiently, extra work is required to sum the frontal matrices together and can be costly because indirect addressing is requred. The (uni)frontal method avoids this extra work by factorizing the matrix with a single frontal matrix. Rows and columns are added to the frontal matrix, and pivot rows and columns are removed. Data movement is simpler, but higher fill-in can result if the matrix cannot be permuted into a variable-band form with small profile. We consider a combined unifrontal/multifrontal algorithm to enable general fill-in reduction orderings to be applied without the data movement of previous multifrontal approaches. We discuss this technique in the context of a code designed for the solution of sparse systems with unsymmetric pattern.
Flexible collaboration transparency
Authors: Begole James , Rosson Mary Beth , Shaffer Clifford A.
Published: July 2002

This article presents a critique of conventional collaboration transparency systems, also called “application-sharing” systems, which provide the real-time shared use of legacy single-user applications. We find that conventional collaboration transparency systems are inefficient in their use of network resources and lack support for key groupware principles: concurrent work, relaxed WYSIWIS, and group awareness. Next, we present an alternative approach to implementing collaboration transparency that provides many features previously seen only in collaboration-aware applicaitons. Our approach is based on a replicated architecture where selected single-user interface components are dynamically replaced by multiuser versions. The replacement occurs at run-time and is transparent to the single-user application and its developers.. As an instance of this approach, we describe its incorporation into a Java-based collaboration transparency system for serializable, Swing-based Java applications, called Flexible JAMM (Java Applets Made Multiuser). To validate that the flexible collaboration transparency system is truly an improvement over conventional systems, we conducted an empirical study of collaborators performing both tightly and loosely coupled tasks using Flexible JAMM versus a representative conventional collaboration transparency system, Microsoft NetMeeting. Completion times were significantly faster in the loosely coupled task using Flexible JAMM and were not adversely affected in the tightly coupled task. Accuracy was equivalent for both systems. Participants greatly preferred Flexible JAMM.
The design of a rotating associative memory for relational database applications
Authors: Lin Chyuan Shiun , Smith Diane C. P. , Smith John Miles
Published: July 2002

The design and motivation for a rotating associative relational store (RARES) is described. RARES is designed to enhance the performance of an optimizing relational query interface by supporting important high level optimization techniques. In particular, it can perform tuple selection operations at the storage device and also can provide a mechanism for efficient sorting. Like other designs for rotating associative stores, RARES contains search logic which is attached to the heads of a rotating head-per-track storage device. RARES is distinct from other designs in that it utilizes a novel “orthogonal” storage layout. This layout allows a high output rate of selected tuples even when a sort order in the stored relation must be preserved. As in certain other designs, RARES can usually output a tuple as soon as it is found to satisfy the selection criteria. However, relative to these designs, the orthogonal layout allows an order of magnitude reduction in the capacity of storage local to the search logic.
On Time Versus Space
Authors: Hopcroft John , Paul Wolfgang , Valiant Leslie
Published: July 2002

It is shown that every deterministic multitape Turing machine of time complexity
t
(
n
) can be simulated by a deterministic Turing machine of tape complexity
t
(
n
)/log
t
(
n
). Consequently, for tape constructable
t
(
n
), the class of languages recognizable by multitape Turing machines of time complexity
t
(
n
) is strictly contained in the class of languages recognized by Turing machines of tape complexity
t
(
n
). In particular the context-sensitive languages cannot be recognized in linear time by deterministic multitape Turing machines.
A second look at bloom filters
Authors: Mullin James K.
Published: July 2002

This note deals with a paper by Gremillion demonstrating the simulation approach to the design of a Bloom filter. It is shown that an analytical approach can yield insights into competing filter design and give expected values for the goodness-of-hash transformations not available with simulation. On the other hand, simulation gives insight into what can be expected with available hash transformation not available from an analytic approach.
State-space problem-reduction, and theorem proving—some relationships
Authors: VanderBrug Gordon J. , Minker Jack
Published: July 2002

This paper suggests a bidirectional relationship between state-space and problem-reduction representations. It presents a formalism based on multiple-input and multiple-output operators which provides a basis for viewing the two types of representations in this manner. A representation of the language recognition problem which is based on the Cocke parsing algorithm is used as an illustration. A method for representing problems in first-order logic in such a way that the inference system employed by a resolution-based theorem prover determines whether the set of clauses is interpreted in the state-space mode or in the problem-reduction mode is presented. The analogous concepts in problem-reduction and theorem proving, and the terminology used to refer to them, are noted. The relationship between problem-reduction, input resolution, and linear resolution is is discussed.
Code size minimization and retargetable assembly for custom EPIC and VLIW instruction formats
Authors: Aditya Shail , Mahlke Scott A. , Rau B. Ramakrishna
Published: July 2002

PICO is a fully automated system for designing the architecture and the microarchitecture of VLIW and EPIC processors. A serious concern with this class of processors, due to their very long instructions, is their code size. One focus of this paper is to describe a series of code size minimization techniques used within PICO, some of which are applied during the automatic design of the instruction format, while others are applied during program assembly. The design of a retargetable assembler to support these techniques also poses certain novel challenges, which constitute the second focus of this paper. Contrary to widely held perceptions, we demonstrate that it is entirely possible to design VLIW and EPIC processors that are capable of issuing large numbers of operational per cycle, but whose code size is only moderately larger than that for a sequential CISC processor.
A comparison of the correlational behavior of random number generators for the IBM 360
Authors: Whittlesey John RB
Published: July 2002

Hutchinson states that the “new” (prime modulo) multiplicative congruential pseudorandom generator, attributed to D.H. Lehmer, has passed the usual statistical tests for random number generators. It is here empirically shown that generators of this type can produce sequences whose
autocorrelation functions
up to lag 50 exhibit evidence of nonrandomness for many multiplicative constants. An alternative generator proposed by Tausworthe, which uses irreducible polynomials over the field of characteristic two, is shown to be free from this defect.

The applicability of these two generators to the IBM 360 is then discussed. Since computer word size can affect a generator's statistical behavior, the older mixed and simple congruential generators, although extensively tested on computers having 36 or more bits per word, may not be optimum generators for the IBM 360.
Soviet cybernetics and computer sciences, 1960
Authors: Feigenbaum Edward A.
Published: July 2002

This article records observations on Soviet research and technology in cybernetics and computer science, made by the author during a visit to the Soviet Union as a delegate to the IFAC Congress on Automatic Control held in Moscow in the summer of 1960.
Process migration
Authors: Milojičić Dejan S. , Douglis Fred , Paindaveine Yves , Wheeler Richard , Zhou Songnian
Published: July 2002

Process migration is the act of transferring a process between two machines. It enables dynamic load distribution, fault resilience, eased system administration, and data access locality. Despite these goals and ongoing research efforts, migration has not achieved widespread use. With the increasing deployment of distributed systems in general, and distributed operating systems in particular, process migration is again receiving more attention in both research and product development. As high-performance facilities shift from supercomputers to networks of workstations, and with the ever-increasing role of the World Wide Web, we expect migration to play a more important role and eventually to be widely adopted.

This survey reviews the field of process migration by summarizing the key concepts and giving an overview of the most important implementations. Design and implementation issues of process migration are analyzed in general, and then revisited for each of the case studies described: MOSIX, Sprite, Mach, and Load Sharing Facility. The benefits and drawbacks of process migration depend on the details of implementation and, therefore, this paper focuses on practical matters. This survey will help in understanding the potentials of process migration and why it has not caught on.
An error-correcting parse algorithm
Authors: Irons E. T.
Published: July 2002

During the past few years, research into so-called “Syntax Directed Compiler” and “Compiler Compiler” techniques [1, 2, 3, 4, 5, 6] has given hope that constructing computer programs for translating formal languages may not be as formidable a task as it once was. However, the glow of the researchers' glee has obscured to a certain extent some very perplexing problems in constructing practical translators for common programming languages. The automatic parsing algorithms indeed simplify compiler construction but contribute little to the production of “optimized” machine code, for example. An equally perplexing problem for many of these parsing algorithms has been what to do about syntactically incorrect object strings. It is common knowledge that most of the ALGOL or FORTRAN “programs” which a compiler sees are syntactically incorrect. All of the parsing algorithms detect the existence of such errors. Many have considerable difficulty pinpointing the location of the error, printing out diagnostic information, and recovering enough to move on to other correct parts of the object string. It is the author's opinion that those algorithms which do the best job of error recovery are those which are restricted to simpler forms of formal languages.
Strategies for encouraging successful adoption of office communication systems
Authors: Ehrlich Susan F.
Published: July 2002

The adoption of new computer communication systems into organizations requires behavioral change. Planning for successful adoption requires knowledge of individual organizational communication patterns and the relationship between those patterns and particular communication system solutions. This paper documents a sequence of studies of organizational communication. Needs for office communication systems were identified, as were social and psychological factors temporarily inhibiting their use. Strategies for assuring smooth adoption of such systems are highlighted.
Computer-based systems for cooperative work and group decision making
Authors: Kraemer Kenneth L. , King John Leslie
Published: July 2002

Application of computer and communications technology to cooperative work and group decision making has grown out of three traditions: computer-based communications, computer:based information service provision, and computer-based decision support. This paper reviews the group decision support systems (GDSSs) that have been configured to meet the needs of groups at work, and evaluates the experience to date with such systems. Progress with GDSSs has proved to be slower than originally anticipated because of shortcomings with available technology, poor integration of the various components of the computing package, and incomplete understanding of the nature of group decision making. Nevertheless, the field shows considerable promise with respect to the creation of tools to aid in group decision making and the development of sophisticated means of studying the dynamics of decision making in groups.
The state of the art in automating usability evaluation of user interfaces
Authors: Ivory Melody Y. , Hearst Marti A
Published: July 2002

Usability evaluation is an increasingly important part of the user interface design process. However, usability evaluation can be expensive in terms of time and human resources, and automation is therefore a promising way to augment existing approaches. This article presents an extensive survey of usability evaluation methods, organized according to a new taxonomy that emphasizes the role of automation. The survey analyzes existing techniques, identifies which aspects of usability evaluation automation are likely to be of use in future research, and suggests new ways to expand existing approaches to better support usability evaluation.
The automated tutoring of introductory computer programming
Authors: Anderson J. R , Skwarecki E.
Published: July 2002

The methodologies of artificial intelligence and the knowledge of cognitive psychology can be used to automatically generate fine-grain tutorial interactions, rather than having to program them manually.
Toward memory-based reasoning
Authors: Stanfill Craig , Waltz David
Published: July 2002

The intensive use of memory to recall specific episodes from the past—rather than rules—should be the foundation of machine reasoning.
ANTHROPOLOGICAL RESEARCH ON HAZARDS AND DISASTERS
Authors: Oliver-Smith Anthony
Published: July 2002

▪ Abstract  Recent perspectives in anthropological research define a disaster as a process/event involving the combination of a potentially destructive agent(s) from the natural and/or technological environment and a population in a socially and technologically produced condition of vulnerability. From this basic understanding three general topical areas have developed: (a) a behavioral and organizational response approach, (b) a social change approach, and (c) a political economic/environmental approach, focusing on the historical-structural dimensions of vulnerability to hazards, particularly in the developing world. Applied anthropological contributions to disaster management are discussed as well as research on perception and assessment of hazard risk. The article closes with a discussion of potentials in hazard and disaster research for theory building in anthropology, particularly in issues of human-environment relations and sociocultural change.
The Historical Archaeology of Native Americans
Authors: Rubertone Patricia E.
Published: July 2002

▪ Abstract  Historical archaeologists have given relatively scant attention to the study of Native Americans. Despite the potential to contribute to new understandings about Native peoples during and after European contact, the research commitment has been ambivalent at best. In this review, I ground this relationship in early debates about the field's subject matter and concurrent discussions in anthropology about direct-historical and acculturation models. In addition, I highlight currents in research that have refined these approaches as well as those that have charted new directions. The latter are notable for helping comprehend the role of place and tradition in Native peoples' lives, but also for reminding us of the complexities of identity construction in America after European contact. I reason that historical archaeology's use of multiple sources, if linked creatively, can be crucial in producing knowledge about the past that illuminates the rich diversity of experiences among Native Americans.

“Did these occurrences have a paradigm…that went back in time? Or are we working out the minor details of a strictly random pattern?” Erdrich ( 1998 :240)

“…all of us remembering what we have heard together—that creates the whole story the long story of the people.” Silko ( 1981 :7)
CIRCADIANRHYTHMS INPLANTS
Authors: McClung C Robertson
Published: July 2002

▪ Abstract  Circadian rhythms, endogenous rhythms with periods of approximately 24 h, are widespread in nature. Although plants have provided many examples of rhythmic outputs and our understanding of photoreceptors of circadian input pathways is well advanced, studies with plants have lagged in the identification of components of the central circadian oscillator. Nonetheless, genetic and molecular biological studies, primarily in Arabidopsis, have begun to identify the components of plant circadian systems at an accelerating pace. There also is accumulating evidence that plants and other organisms house multiple circadian clocks both in different tissues and, quite probably, within individual cells, providing unanticipated complexity in circadian systems.
MODELS OF AMYLOID SEEDING IN ALZHEIMER'S DISEASE AND SCRAPIE: Mechanistic Truths and Physiological Consequences of the Time-Dependent Solubility of Amyloid Proteins
Authors: Harper James D. , Lansbury Peter T.
Published: July 2002

Ordered protein aggregation in the brain is a hallmark of Alzheimer's disease and scrapie. The disease-specific amyloid fibrils comprise primarily a single protein, amyloid β, in Alzheimer's disease, and the prion protein in scrapie. These proteins can be induced to form aggregates in vitro that are indistinguishable from brain-derived fibrils. Consequently, much effort has been invested in the development of in vitro model systems to study the details of the aggregation processes and the effects of endogenous molecules that have been implicated in disease. Selected studies of this type are reviewed herein. A simple mechanistic model has emerged for both processes that involves a nucleation-dependent polymerization. This mechanism dictates that aggregation is dependent on protein concentration and time. Furthermore, amyloid formation can be seeded by a preformed fibril. The physiological consequences of this mechanism are discussed.
REPLICATION PROTEIN A: A Heterotrimeric, Single-Stranded DNA-Binding Protein Required for Eukaryotic DNA Metabolism
Authors: Wold Marc S.
Published: July 2002

Replication protein A [RPA; also known as replication factor A (RFA) and human single-stranded DNA-binding protein] is a single-stranded DNA-binding protein that is required for multiple processes in eukaryotic DNA metabolism, including DNA replication, DNA repair, and recombination. RPA homologues have been identified in all eukaryotic organisms examined and are all abundant heterotrimeric proteins composed of subunits of approximately 70, 30, and 14 kDa. Members of this family bind nonspecifically to single-stranded DNA and interact with and/or modify the activities of multiple proteins. In cells, RPA is phosphorylated by DNA-dependent protein kinase when RPA is bound to single-stranded DNA (during S phase and after DNA damage). Phosphorylation of RPA may play a role in coordinating DNA metabolism in the cell. RPA may also have a role in modulating gene expression.
The Molecular Basis of Hypertension
Authors: Garbers David L. , Dubois Susan K.
Published: July 2002

▪ Abstract  More than 50 million Americans display blood pressures outside the safe physiological range. Unfortunately for most individuals, the molecular basis of hypertension is unknown, in part because pathological elevations of blood pressure are the result of abnormal expression of multiple genes. This review identifies a number of important blood pressure regulatory genes including their loci in the human, mouse, and rat genome. Phenotypes of gene deletions and overexpression in mice are summarized. More detailed discussion of selected gene products follows, beginning with proteins involved in ion transport, specifically the epithelial sodium channel and sodium proton exchangers. Next, proteins involved in vasodilation/natriuresis are discussed with emphasis on natriuretic peptides, guanylin/uroguanylin, and nitric oxide. The renin angiotensin aldosterone system has an important role antagonizing the vasodilatory cyclic GMP system.
Analysis of Proteins and Proteomes by Mass Spectrometry
Authors: Mann Matthias , Hendrickson Ronald C. , Pandey Akhilesh
Published: July 2002

▪ Abstract  A decade after the discovery of electrospray and matrix-assisted laser desorption ionization (MALDI), methods that finally allowed gentle ionization of large biomolecules, mass spectrometry has become a powerful tool in protein analysis and the key technology in the emerging field of proteomics. The success of mass spectrometry is driven both by innovative instrumentation designs, especially those operating on the time-of-flight or ion-trapping principles, and by large-scale biochemical strategies, which use mass spectrometry to detect the isolated proteins. Any human protein can now be identified directly from genome databases on the basis of minimal data derived by mass spectrometry. As has already happened in genomics, increased automation of sample handling, analysis, and the interpretation of results will generate an avalanche of qualitative and quantitative proteomic data. Protein-protein interactions can be analyzed directly by precipitation of a tagged bait followed by mass spectrometric identification of its binding partners. By these and similar strategies, entire protein complexes, signaling pathways, and whole organelles are being characterized. Posttranslational modifications remain difficult to analyze but are starting to yield to generic strategies.
Properties and Biological Activities of Thioredoxins
Authors: Powis Garth , Montfort William R
Published: July 2002

▪ Abstract  The mammalian thioredoxins are a family of small (approximately 12 kDa) redox proteins that undergo NADPH-dependent reduction by thioredoxin reductase and in turn reduce oxidized cysteine groups on proteins. The two main thioredoxins are thioredoxin-1, a cytosolic and nuclear form, and thioredoxin-2, a mitochondrial form. Thioredoxin-1 has been studied more. It performs many biological actions including the supply of reducing equivalents to thioredoxin peroxidases and ribonucleotide reductase, the regulation of transcription factor activity, and the regulation of enzyme activity by heterodimer formation. Thioredoxin-1 stimulates cell growth and is an inhibitor of apoptosis. Thioredoxins may play a role in a variety of human diseases including cancer. An increased level of thioredoxin-1 is found in many human tumors, where it is associated with aggressive tumor growth. Drugs are being developed that inhibit thioredoxin and that have antitumor activity.
Retinylidene Proteins: Structures and Functions from Archaea to Humans
Authors: Spudich John L. , Yang Chii-Shen , Jung Kwang-Hwan , Spudich Elena N.
Published: July 2002

▪ Abstract  Retinylidene proteins, containing seven membrane-embedded α-helices that form an internal pocket in which the chromophore retinal is bound, are ubiquitous in photoreceptor cells in eyes throughout the animal kingdom. They are also present in a diverse range of other organisms and locations, such as archaeal prokaryotes, unicellular eukaryotic microbes, the dermal tissue of frogs, the pineal glands of lizards and birds, the hypothalamus of toads, and the human brain. Their functions include light-driven ion transport and phototaxis signaling in microorganisms, and retinal isomerization and various types of photosignal transduction in higher animals. The aims of this review are to examine this group of photoactive proteins as a whole, to summarize our current understanding of structure/function relationships in the best-studied examples, and to report recent new developments.