bluuebunny/crossref_metadata_2025_split huggingface dataset:
STUDY OF THE ELECTRODYNAMIC RESPONSE OF MgB2 SINTERED PELLETS AND THIN FILMS
Authors: ANDREONE A. , DI GENNARO E. , LAMURA G. , SALLUZZO M. , LE COCHEC J. , GAUZZI A. , CANTONI C. , PARANTHAMAN M. , CERESARA S. , GIUNCHI G. 
Published: July 2002

We present a number of experimental results on the temperature dependence of the magnetic penetration depth λ and on the temperature and field dependence of the microwave surface impedance Z s =R s +iX s in both pellets and thin films of MgB2 , exhibiting critical temperatures ranging between 26 and 38 K. Accurate measurements of Z s (H,T) were performed by means of a sapphire dielectrically loaded cavity operating in the microwave region (20 GHz). The study of λ(T) was carried out employing a single coil mutual inductance technique in the MHz region. An anisotropic s-wave BCS model can account for the temperature dependence experimentally observed in the penetration depth data of the best films, confirming previous reports on the conventional nature of superconductivity in diborides. On the contrary, films having a reduced value of the critical temperature and pellets show no evidence of saturation, and the experimental results strictly follow a quadratic dependence down to the lowest temperatures. We explain this behavior with the presence of metallic Mg inclusions that may locally depress the gap. The study of the surface impedance versus temperature and field shows also that the source of microwave loss can be markedly different, depending on the structural and transport properties of the samples.
Investigation of the Quasicrystalline State of the D-Al67.5Cu17.5Rh15 and I-Al70Cu12Ru18 alloys
Authors: Athanasiou N. S. , Spirlet J. C. , Zwirner S. , Baskoutas S. 
Published: July 2002

In the present study we report on the formation, characterization and magnetic susceptibility of two conventionally solidified quasicrystalline alloys with the nominal composition Al 67.5 Cu 17.5 Rh 15 (decagonal phase) and Al 70 Cu 12 Ru 18 (icosahedral phase). The characterization of the quasicrystalline state was examined by X-ray diffractometry (XRD), differential thermal analysis (DTA), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDXA). Magnetic susceptibility results in the temperature range from 5 to 300 K utilizing SQUID magnetometry under constant magnetic field H=1 kOe are presented.
ARTIN PRESENTATIONS I: GAUGE THEORY, 3 + 1 TQFT'S AND THE BRAID GROUPS
Authors: WINKELNKEMPER H. E. 
Published: July 2002

We inititate the systematic study of Artin Presentations, (discovered in 1975 by González-Acuña), which characterize the fundamental groups of closed, orientable 3-manifolds, and form a discrete equivalent of the theory of open book decompositions with planar pages of such manifolds. We list and prove the basic properties, state some fundamental problems and describe some of the advantages of the theory: e.g., an Artin Presentation of π1 (M3) does not just determine the closed, orientable 3-manifold M3, but also a canonical, smooth simply-connected cobordism of it, allowing us to tap into 4-dimensional gauge theory (and 3 + 1 TQFT's) in a more direct, purely discrete, functorial manner than others. Thus, in section 4, instead of using PDE's, we show how a canonical action of the commutator subgroup [Pn, Pn] of the pure braid group Pn can be used to study the smooth structures on a closed, smooth-connected 4-manifold with b2 = n, in a systematic way. However, the main purpose of this first paper is to Artin Presentations to set up simple criteria, testable with, say, MAGMA on the computer (where then no knowledge of topology is required) for finding explicit counter-examples to the so-called Weak Poincaré Conjecture: "Every homotopy 3-sphere bounds a smooth, compact, contractible 4-manifold," as well as: "Every irreducible Z-homology 3-sphere Σ, with π1 (Σ) = I (120) is homeomorphic to Σ (2, 3, 5)" and other conjectures implied by Thurston's Geometrization Conjecture. One first philosophical goal is to convince the reader that the truth of these conjectures is at least as unlikely as that of the Andrews-Curtis Conjecture and that ultimately, Artin Presentation Theory is a non-trivial intersection of string/M theory number theory.
THE ORIENTATION OF BENZENE ON BIMETALLIC SURFACES
Authors: KOSCHEL H. , HELD G. , STEINRÜCK H.-P. 
Published: July 2002

Angle-resolved UV photoelectron spectroscopy (ARUPS) using linearly polarized synchrotron radiation is used to determine the orientation of benzene molecules on two modifications of the pseudomorphic Ni/Cu(111) layer, the Ni-terminated adlayer and the Cu-terminated Ni sublayer. It is found that the molecules adsorb with their C–H bonds 30° off the close-packed substrate rows (σv orientation) on the Ni adlayer whereas no preferential orientation was found for the Cu-terminated Ni sublayer. For these and other close-packed mono- and bimetallic surfaces involving Cu, Ni and Ru, the correlation between adsorption geometry and reactivity of benzene is explored in connection with temperature-programmed desorption (TPD). Like for the Ni/Cu(111) sublayer, no preferential lateral orientation and a weak bond is found on most other Cu-terminated surfaces at 80 K. This goes along with the absence of any dissociation on these surfaces. Only on the stretched 1 ML Cu/Ru(0001) surface is the substrate–benzene bond strong enough to induce a clear preferential orientation (σd with C–H bonds parallel to the close-packed rows) but still too weak to induce dissociation. The same orientation was found for the saturated benzene layer on Ni(111) where the molecules also do not dissociate. Dissociation is, however, observed for the saturation coverage of benzene on the Ni/Cu(111) adlayer and for low benzene coverages on Ni(111). On these surfaces the azimuthal orientation of the benzene molecules is σv, i.e. rotated by 30° with respect to the close-packed rows.
CONFRONTING MODEL MISSPECIFICATION IN FINANCE: TRACTABLE COLLECTIONS OF SCENARIO PROBABILITY MEASURES FOR ROBUST FINANCIAL OPTIMIZATION PROBLEMS
Authors: FRIEDMAN CRAIG 
Published: July 2002

Despite the widespread realization that financial models for contingent claim pricing, asset allocation and risk management depend critically on their underlying assumptions, the vast majority of financial models are based on single probability measures. In such models, asset prices are assumed to be random, but asset price probabilities are assumed to be known with certainty, an obviously false assumption. We explore practical methods to specify collections of probability measures for an assortment of important financial problems; we provide practical methods to solve the robust financial optimization problems that arise and, in the process, discover "dangerous" measures.
New Formulas for Computing Incomplete Elliptic Integrals of the First and Second Kind
Authors: DiDonato A. R. , Hershey A. V. 
Published: July 2002

New series expansions are developed for computing incomplete elliptic integrals of the first and second kind when the values of the amplitude and modulus are large. The classical series, which are obtained after a binomial expansion of the integrands, are used when the values of the amplitude and modulus are small. The range of use of each series is so selected as to maintain a minimum of rounding error. A special criterion is used to determine when the binomial series should be terminated.
The calculation of elliptic integrals by these series expansions is compared with the calculation by the previously established Landen transformation, which has been used by Legendre. The new series yield more accurate results and the average time of computation is 30 per cent shorter. The computing program in the NORC subroutine for the calculation of elliptic integrals is described.
An implemented graph algorithm for winning Shannon Switching Games
Authors: Chase Stephen M. 
Published: July 2002

In this tutorial paper a computer program which wins Shannon Switching Games is described. Since these games are played on graphs, the program is a good example of the implementation of graph algorithms.
The two players in a Shannon Switching Game, CONNECT and CUT, have nonsimilar goals. Either CONNECT, CUT, or the player moving first is guaranteed the existence of a winning strategy. The simple strategy explained in this paper is valid in all three cases. In fact, the major routines never need to know whether the computer is CONNECT or CUT.
Computer accessibility for federal workers with disabilities: it's the law
Authors: Ladner Richard E. 
Published: July 2002

In 1986, Congress passed Public Law 99-506, the "Rehabilitation Act Amendments of 1986." This law, amending the famous Rehabilitation Act of 1973, contains a small section, titled "Electronic Equipment Accessibility," Section 508, which may have significant impact on the design of computer systems and their accessibility by workers with disabilities. The bill became law when it was signed by former President Reagan on October 21, 1986.
The purpose of this article is to inform concerned computer professionals of Section 508, outline the guidelines and regulations pursuant to the law, describe some of the reaction to the guidelines and regulations, and describe some of the challenges for the future in meeting the computer accessibility needs of users with disabilities.
Section 508 was developed because it was realized that government offices were rapidly changing into electronic offices with microcomputers on every desk. In order for persons with disabilities to keep their jobs or gain new employment in the government, Congress decided it was necessary to make provisions to guarantee accessibility to microcomputers and other electronic office equipment. The driving principle behind Section 508 can be found in Section 504 of the Rehabilitation Act of 1973 which states:
No otherwise qualified handicapped individual in the United States . . . shall, solely by reason of his handicap, be excluded from the participation in, be denied the benefits of, or be subjected to discrimination under any program or activity receiving Federal financial assistance.

It should be stated off the top that the scope of Section 508 is not as broad as Section 504. In particular, Section 508 only applies to direct purchases by the federal government and
not
to purchases made by all programs receiving government funding.

Section 508 does not specify what the guidelines should be nor does it delineate a philosophy on which to base the guidelines. A committee established by the National Institute on Disability and Rehabilitation Research (NIDRR) and the General Services, Administration (GSA), in consultation with the electronics industry, rehabilitation engineers, and disabled computer professionals worked for a year developing the philosophy and guidelines which will significantly affect the purchase of electronic office equipment, including computers and software, by the federal government, the largest computer customer in the world.
Legally speaking: should program algorithms be patented
Authors: Samuelson Pamela 
Published: July 2002

In the Legally Speaking column last May [6], we reported on a survey conducted at last year's ACM-sponsored Conference on Computer-Human Interaction in Austin, Tex. Among the issues about which the survey inquired was whether the respondents thought patent protection should be available for various aspects of computer programs. The 667 respondents overwhelmingly supported copyright protection for source and object code although they strongly opposed copyright or patent protection for “look and feel” and most other aspects of programs. Algorithms were the only aspect of programs for which there was more than a small minority of support for patent protection. Nevertheless, more than half of the respondents I opposed either copyright or patent protection for algorithms. However, nearly 40 percent of the respondents regarded algorithms as appropriately protected by patents. (Another eight percent would have copyright law protect them.)
We should not be surprised that these survey findings reflect division within the technical community about patents as a form of protection for this important kind of computer program innovation. A number of prominent computer professionals who have written or spoken about patent protection for algorithms or other innovative aspects of programs have either opposed or expressed reservations about this form of protection for software [2, 4, 5].
This division of opinion, of course, has not stopped many firms and some individuals from seeking patent protection for algorithms or other software innovations [8]. Although the Refac Technology patent infringement lawsuit against Lotus and other spreadsheet producers may be in some jeopardy, it and other software patent lawsuits have increased awareness of the new availability of software patents. This situation, in turn, has generated some heated discussion over whether this form of legal protection will be in the industry's (and society's) long-term best interests.
The aim of this column is to acquaint readers with the legal debate on patent protection for algorithms and other computer program innovations, an issue which seems to be as divisive among lawyers as those in the computer field. [3, 9].
A study of scalar compilation techniques for pipelined supercomputers
Authors: Weiss Shlomo , Smith James E. 
Published: July 2002

This paper studies two compilation techniques for enhancing scalar performance in high-speed scientific processors: software pipelining and loop unrolling. We study the impact of the architecture (size of the register file) and of the hardware (size of instruction buffer) on the efficiency of loop unrolling. We also develop a methodology for classifying software pipelining techniques. For loop unrolling, a straightforward scheduling algorithm is shown to produce near-optimal results when not inhibited by recurrences or memory hazards. Our study indicates that the performance produced with a modified CRAY-1S scalar architecture and a code scheduler utilizing loop unrolling is comparable to the performance achieved by the CRAY-1S with a vector unit and the CFT vectorizing compiler.
Finally, we show that the combination of loop unrolling and dynamic software pipelining, as implemented by a decoupled computer, substantially outperforms the vector CRAY-1S.
Legally speaking: how to interpret the Lotus decision (and how not to)
Authors: Samuelson Pamela 
Published: July 2002

On June 28, 1990, a federal court judge in Boston made public his decision in favor of Lotus Development Corporation in its software copyright lawsuit against Paperback Software. People in the software industry had been waiting for this decision since the lawsuit was first filed in January 1987, certain that it would be a landmark case and would resolve many vexing questions about copyright protection for user interfaces.
The trade press has abounded with varying interpretations of Judge Keeton's opinion in the Lotus case: Some have said the decision is a narrow one, making illegal only the direct copying of another firm's interface [9]; Some have seen it has a much broader ruling—one that will have a chilling effect on development of competitive software products [5]; Others have asserted the case draws a reasonable line, and will have a positive effect overall [4]; Several have argued the ruling will be harmful because it ignores the interests of users of software, and will make standardization of user interfaces impossible to achieve. [3] Still others perceive the opinion as only setting the stage for a new confrontation over the issues in the appellate courts. [1] Lotus has given some indication of how broadly it interprets the Paperback decision by filing a new round of user interface copyright lawsuits against two of its other spreadsheet competitors.
his column, rather than just adding one more interpretation of the Lotus decision to the bin of those already expressed, will give the reader a glimpse of the nature of the legal process and of judicial opinions so he or she can see why people can interpret the Lotus opinion differently. The following three factors make it difficult to know what the Lotus decision means: 1) The legal process is not yet over, and the meaning of the case will depend in part on the outcome of this further process. 2) While Judge Keeton makes some statements that seem to suggest his ruling is a narrow one, some of his other statements could be interpreted much more broadly. 3) Even from unambiguous statements Judge Keeton makes, different people can draw reasonable but nonetheless differing inferences about what the judge would do in similar (though somewhat different) cases. For these reasons, it is impossible to know with any certainty what the law concerning copyright protection for user interfaces is in the aftermath of the Lotus decision.
A Model that Accounts for Activity Prior to Sensory Inputs and Responses During Matching-to-Sample Tasks
Authors: Moody Sohie Lee , Wise Steven P. 
Published: July 2002

Abstract
Neural network models were examined during delayed matching-to-sample tasks (DMS), and neurons in a monkey's prefrontal cortex were studied during the performance of comparable tasks. In DMS, various input stimuli follow a sample stimulus, and an output should occur whenever the sample reappears. Our previous models have been restricted to certain kinds of inputs, outputs, and temporal patterns. Here, we generalized the models by training them on both spatial and nonspatial inputs, spatial and nonspatial outputs, and both fixed and variable interstimulus intervals. Two versions of DMS were presented to both the model and the monkey, both involving nonspatial samples: (1) Two stimuli simultaneously appeared at a variable interval after the sample; and (2) A series of single stimuli appeared at fixed intervals after the sample. Both versions required identical spatial responses, reflecting the direction (left or right) of the matching stimulus relative to a central origin. Thus, these two versions of DMS involved the same samples, memory, and responses, but established different response contexts. Our analysis focused on unit activity prior to stimuli, as well as that prior to responses, termed anticipatory and response-related activity, respectively. In both the model and the monkey, anticipatory activity occurred only for fixed interstimulus intervals. In the model, we could determine that anticipatory activity acted either like a filter to suppress inappropriate responses or it served to enhance the network's general readiness to respond. As for response-related activity, units in both the model and the monkey showed directional selectivity and had a strong dependence on response context. In the model, we could show that this activity contributed both to the suppression of inappropriate responses and to the generation of correct ones. None of the model's hidden units contributed exclusively to computing the direction of match output. Instead, their response-related activity contributed to the computation of both the match decision and the correct response direction.
Object Activation from Features in the Semantic System
Authors: Kraut Michael A. , Kremen Sarah , Segal Jessica B. , Calhoun Vincent , Moo Lauren R. , Hart John 
Published: July 2002

Abstract
The human brain is thought to elicit an object representation via co-activation of neural regions that encode various object features. The cortical regions and mechanisms involved in this process have never been elucidated for the semantic system. We used functional magnetic resonance imaging (fMRI) to evaluate regions activated during a task designed to elicit object activation within the semantic system (e.g., presenting the words “desert” and “humps” with the task to determine if they combine to form an object, in this case a “camel”). There were signal changes in the thalamus for word pairs that activated an object, but not for pairs that (a) failed to activate an object, (b) were simply semantically associated, or (c) were members of the same category. These results suggest that the thalamus has a critical role in coordinating the cortical activity required for activating an object concept in the semantic system.
Worldlets: 3-D Thumbnails for Wayfinding in Large Virtual Worlds
Authors: Elvins T. Todd , Nadeau David R. , Schul Rina , Kirsh David 
Published: July 2002

Finding one's way to sites of interest on the Web can be problematic, and this difficulty has been recently exacerbated by widespread development of 3-D Web content and virtual-world browser technology using the Virtual Reality Modeling Language (VRML). Whereas travelers can often navigate 2-D Web sites based on textual and 2-D thumbnail image representations of the sites' content, finding one's way to destinations in 3-D environments is notoriously troublesome. Wayfinding literature provides clear support for the importance of landmarks in building a cognitive map and then using that map to navigate in a 3-D environment, be it real or virtual. Textual and 2-D image landmark representations, however, lack the depth and context needed for travelers to reliably recognize 3-D landmarks. This paper describes a novel 3-D thumbnail landmark affordance called a worldlet. Containing a 3-D fragment of a virtual world, worldlets offer travelers first-person, multi-viewpoint experience with faithful representations of potential destinations. To facilitate an investigation into the comparative advantages of landmark affordances for wayfinding, worldlet capture algorithms were designed, implemented, and incorporated into two VRML-based virtual environment browsers. Findings from a psychological experiment using one of these browsers revealed that, compared to textual and image guidebook usage, worldlet guidebook usage: nearly doubled the time subjects spent studying the landmarks in the guidebook, significantly reduced the time required for subjects to reach landmarks, and reduced backtracking to almost zero. These results support the hypothesis that worldlets facilitate traveler landmark knowledge, expedite wayfinding in large virtual environments, and enable skilled wayfinding.
ADDE PRAEPUTIUM PRAEPUTIO MAGNUS ACERVUS ERIT: IF THE EXODUS AND CONQUEST HAD REALLY HAPPENED
Authors: Grabbe Lester 
Published: July 2002

AbstractA lot of "what if" situations in history can be imagined, with interesting results. But an event often taken as history in the past is now regarded as a literary creation the exodus and conquest. When we begin to see the consequences of taking it as actual history-surprisingly, not done by supporters of this interpretation-it becomes even clearer why there never was such an event. If the exodus and conquest had actually occurred, the outcome could have changed the whole of the history of the Western world, and we would have a completely different Bible today.