bluuebunny/crossref_metadata_2025 huggingface dataset:
INFLUENCE OF PRESSURE ON THE DIAMAGNETIC SUSCEPTIBILITY OF HYDROGENIC DONOR IN SOME LOW-LYING EXCITED STATES IN A QUANTUM WELL
Authors: NITHIANANTHI P. , JAYAKUMAR K.
Published: April 2007

The influence of Γ–X band crossing due to the applied hydrostatic pressure on the diamagnetic susceptibility (χ dia ) of a donor in low-lying excited states like 2s, 2p0, 2p± in a GaAs / Al x Ga 1-x As Quantum Well has been investigated in the effective mass approximation by considering the nonparabolicity of the conduction band. We notice that the effect of Γ–X band mixing is significant on χ dia of a donor lying in excited states. Moreover, the effect of non-parabolicity on χ dia is also predominant for lower well width region. The results are presented and discussed.
ELECTRICALLY TUNABLE "RENORMALIZATION" OF s–d EXCHANGE INTERACTION IN A DILUTED MAGNETIC SEMICONDUCTOR QUANTUM DOT
Authors: GNANASEKAR K. , NAVANEETHAKRISHNAN K.
Published: April 2007

We theoretically demonstrate that how the Rashba spin–orbit interaction induced by the external electric field can be used to manipulate spin degree of freedom of electrons in a diluted magnetic semiconductor quantum dot (DMS QD) in the presence of a weak perpendicular magnetic field. The effects of Rashba spin–orbit interaction, induced by the electrostatic potential, on the apparent total spin splitting in a diluted magnetic semiconductor quantum dot have been studied. We propose that the apparent total spin splitting is the result of electrically tunable "renormalization" of s–d exchange interaction. It could be favorably engineered to electrically tune the spin degree of freedom in the spintronic devices.
PI AND SZEGED INDICES OF A VC5C7 [4p, 8] NANOTUBE
Authors: ASHRAFI A. R. , SAATI H.
Published: April 2007

The Padmakar–Ivan (PI) index of a graph G is defined as PI (G) = ∑[neu(e|G) + nev(e|G)], where neu(e|G) is the number of edges of G lying closer to u than to v, nev(e|G) is the number of edges of G lying closer to v than to u and summation goes over all edges of G. In this paper, the PI and Szeged indices of T = VC 5 C 7[4p, 8] nanotube is computed for the first time.
POTENTIAL UNUSUAL CHEMICAL BONDING IN MIXED METAL STRUCTURES OF THE 3d TRANSITION SERIES CONTAINING THE ELEMENTNi
Authors: BUCKNUM MICHAEL J. , CASTRO EDUARDO A.
Published: April 2007

A heuristic proposal is made in this communication that involves potentially unusual chemical bonding between the 3d transition series element Ni and the 3d transition series metals preceding it in the Periodic Table. The bonding in such mixed metal dimers, and their potential realizations as some simple three-dimensional (3D) extended structures in a one-to-one stoichiometry, as sphaelerite, rocksalt or CsCl structure-types, is proposed to include two principal components that involve either covalent or ionic contributions. Ordinary covalent contributions from a σ bond (or band) formed from overlap of singly occupied 4s atomic orbitals on each metal center are proposed to be operative in these molecules (or their extended realizations). However, in addition to this 4s–4s σ bond (band), an unprecedented transfer of a d electron from the incomplete, open 3d9subshell of the transition metal involved in the bonding that precedes Ni in the Periodic Table, into the 3d9subshell on the Ni center, which results in completion of this 3d subshell in Ni , is here implicated as a further driving force for the formation of these species. The resulting molecular and extended structures MNi , where M is a 3d transition metal preceding Ni in the Periodic Table (i.e. M = Sc , Ti , V , Cr , Mn , Fe and Co ), are therefore proposed to be bonded together by a combination of covalent and ionic forces, such that the Ni center acts as an anion of charge 1-, a so-called nickelide anion Ni-, while its counterpart is a univalent cation M+. This proposal is consistent with commonly employed electronegativity scales of chemical bonding, and with considerations of the relative orbital energies of the 3d subshells of the elements across the 3d transition series period, as well as with known trends in covalent and ionic bonding in the Periodic Table of the elements. It is also found to be in agreement with the spin multiplicities calculated in the nickel dimers MNi ( M = Sc , Ti , V , Cr , Mn , Fe and Co ) if Hund's rule is assumed to be operative.
MOLECULAR DYNAMICS STUDY OF ADSORPTION OF FLUORIC POLYMERS ON TATB SURFACE
Authors: LIU JIAN , NIE FUDE , LI JINSHAN , ZHAO XIAOPING , HE TIENING
Published: April 2007

Molecular dynamics simulation has been applied to study the adsorption process of PVDF/PCTFE copolymers on TATB (001) surfaces. The copolymers were formed by linking PVDF and PCTFE in 1:1 proportion as ABABAB pattern with the degree of polymerization N ranging from 10 to 200. The equilibrium time of each chain is several hundred picoseconds, and the adsorption energy E a increases with the distance H between the chain and the increased surface. Adsorption process occurs when H is below 10 Å, and E a tends to be zero as H becomes greater than 10 Å. Polymer's adsorbability is related to the length of the chain, and a longer chain is better than a short one. A short chain has more train conformation monomers than a long chain. Chain conformation changes greatly during the first hundred ps, and stabilizes after 150 ps. Monomers close to the TATB surface are easy to approach the surface, and the units far from the surface will approach the surface by chain torsion and bond rotation. The ratio of the number of train conformation monomers to the degree of polymerization N t /N increases with the increasing MD simulation time.
DEVELOPMENT AND NUMERICAL ANALYSIS OF "BLACK-BOX" COUNTERPROPAGATING WAVE ALGORITHM FOR EXACT QUANTUM SCATTERING CALCULATIONS
Authors: POIRIER BILL
Published: April 2007

In a recent series of papers,1-3 a bipolar counter-propagating wave decomposition, Ψ = Ψ+ + Ψ-, was presented for stationary bound states Ψ of the one-dimensional Schrödinger equation, such that the components Ψ± approach their semiclassical WKB analogs in the large action limit. The corresponding bipolar quantum trajectories are classical-like and well-behaved, even when Ψ has many nodes, or is wildly oscillatory. In this paper, the earlier results are used to construct an universal "black-box" algorithm, numerically robust, stable and efficient, for computing accurate scattering quantities of any quantum dynamical system in one degree of freedom.
SEMICLASSICAL ELECTRONEGATIVITY AND CHEMICAL HARDNESS
Authors: PUTZ MIHAI V.
Published: April 2007

The semiclassical path integral approach is undertaken to develop new definitions and atomic scales of electronegativity and chemical hardness. The considered quantum probability amplitude up to the fourth-order expansion provides intrinsic electronegativity and chemical hardness analytical expressions in terms of principal quantum number of the concerned valence shell and of the effective atomic charge including screening effects. The present electronegativity scale strikes on different orders of magnitude down groups of the periodic table, while still satisfying the main required acceptability criteria regarding the finite difference–based scale. The actual chemical hardness scale improves the trend across periods of the periodic system, avoiding the usual irregularities within the old-fashioned energetic picture. The current quest introduces the electronegativity of an element as the power by which the frontier electrons are attracted to the center of the atom being a stability measure of the atomic system as a whole.
BIOCOMPUTATIONAL ANALYSIS AND CHARACTERIZATION OF SOME ANTIFREEZE PROTEINS
Authors: SIVAKUMAR K. , BALAJI S. , RADHAKRISHNAN GANGA
Published: April 2007

Novel bioinformatic procedures and computational methods have been used to analyze, characterize and provide more detailed description of some selected fish antifreeze proteins (AFPs) retrieved from Swiss–Prot database. Analysis shows that AFPs are rich in non-polar residues and that the AFPs Q01758 and P05140 contain SS bonds. The aliphatic index computed by ExPasy's ProtParam infers that AFPs may be stable for a wide range of temperatures and the AFP P80961 is classified as an unstable protein. The very low GRAVY index of AFP P80961 infers its higher hydrosolubility. Secondary structure analysis shows that the flounder and sculpin fish AFPs are found to be of predominant ∝–helical structures and the rest of them are with mixed secondary structures. The average molecular weight of AFPs computed is 9584 Da. SOSUI server predicts one transmembrane region in P04002 (winter flounder fish) and two regions in P09031 (yellowtail flounder fish). The predicted transmembrane regions were visualized and analyzed using helical wheel plots generated by EMBOSS pepwheel tool. The residues A, L, G and N are identified as the antigenic sites by EMBOSS antigenic program. The presence of 11 Cys residues in AFPs Q01758 (rainbow smelt fish) and P05140 (sea raven fish) indicates the presence of disulfide bridges (SS bonds) in these AFPs, and it is also recognized by CYS_REC tool and well documented from the three dimensional structure using Rasmol tool.
NEUROFUZZY MODELING OF NATURAL FREQUENCIES OF CYLINDRICAL SHELLS APPLIED TO EVOLUTIONARY BASED OPTIMAL DESIGN OF SR MOTORS
Authors: ROUHANI HOSSEIN , BAHRAMI MANSOUR NIKKHAH , ARAABI BABAK NADJAR , LUCAS CARO
Published: April 2007

A thorough analysis of cylindrical shells' dynamical behavior is essential in many different industrial design problems, and particularly in electric motor design. Shell vibration equations form a set of partial differential equations of order eight, where their closed form solution is only known for few special cases with a few known boundary conditions along with many not necessarily realistic assumptions. On the other hand, finite element based numerical solutions does not yield a lumped model that can be regarded as a general solution for natural frequencies of cylindrical shells.

In this paper, a neurofuzzy model for natural frequencies of cylindrical shells is developed. At first, natural frequencies are calculated for a wide range of cylindrical shells' dimensions, using either closed form solution or finite element method. Gathered data is exploited for training of a Locally Linear Neurofuzzy Network, which yields a general model for calculation of natural frequencies of cylindrical shells. While the developed neurofuzzy model may be used in different design problems that deals with cylindrical shells, as a case study, the proposed model along with an evolutionary algorithm are utilized in the optimal design of a Switched Reluctance motor.
A problem by Jensen
Authors: Knight William
Published: April 2007

Throughout, all matrices are real, S denotes a symmetric matrix, T a lower triangular matrix, and D a diagonal matrix. The following problem appeared in the May Signum Newsletter [1]. Given S, for what values of μ can T and D be found such that TDT
t
= (S - μI)? A sufficient condition is that μ not be an eigenvalue of any proper leading diagonal submatrix of S. A necessary and sufficient condition is this. Let m(ν) be the multiplicity of μ as an eigenvalue of the leading ν by ν diagonal submatrix of S, zero if μ is not an eigenvalue of that submatrix. The condition is that the sequence, m(ν), (including the element for S as an improper submatrix of itself) be nondecreasing. This follows from the lemma below.
Methods for stiff differential equations
Authors: Bjurel G. , Lindberg B.
Published: April 2007

Under supervision of professor G. Dahlquist different approaches to the numerical solution of stiff differential equations have been studied at our institute. As an introduction to the subject a survey of methods and applications up to 1970 (1) was made.
An efficient method for the numerical solution of one-phase Stefan problems (abstract)
Authors: Shampine L. F. , Thompson R. J.
Published: April 2007

The purpose of this talk is to discuss an implicit numerical method for the solution of a class of Stefan problems. The method is efficient in the sense that, although the location of the moving boundary is determined by solving a sequence of problems, the amount of computation done to advance the solution one time step is little more than would be required if the boundary were fixed.
Efficient FORTRAN subprograms for the solution of elliptic partial differential equations (abstract)
Authors: Swarztrauber Paul , Sweet Roland
Published: April 2007

The purpose of this paper is to describe technical note, NCAR TN/IA-109, which is intended to provide scientists with a package of computer programs which make use of current methods for solving elliptic partial differential equations. Computer models of geophysical processes often require the numerical solution of elliptic partial differential equations. This is particularly true for models which make use of stream functions, velocity potentials, or vorticity equations, or in which the pressure of an incompressible fluid is computed. The numerical solution of elliptic equations can be a formidable programming task. Also, the equations are often time-dependent, requiring repeated solutions and, hence, considerable computing resources. Efficient, reliable, and well-documented computer subroutines for solving such equations are needed. With recent advances in computing methods, it became apparent to the authors that a very large class of elliptic equations (separable) could be solved rapidly and with minimal storage. Of particular importance was the fact that, as a result of work on singular problems, this class was free of special cases for which solutions could not be obtained numerically.
TEDDY2
Authors: Polak S. J. , Philips N. V.
Published: April 2007

Applied physicists usually do not want to solve their problem with a computer, they want to have it solved by a computer.
Chebyshev approximation with non-continuous weight functions
Authors: Dunham Charles B.
Published: April 2007

The theory of Chebyshev approximation with respect to a positive continuous (ordinary) weight function is well understood and the Remez algorithm can be used in most cases of practical interest. The problem of Chebyshev approximation with respect to a non-negative, non-continuous weight function is now under investigation by the author, who would like to hear from any reader having a problem of this type. In return for such information the author will supply the theory and methods developed to date.
On the use of rank-one updates in the solution of stiff systems of ordinary differential equations
Authors: Hindmarsh A. C. , Byrne G. D.
Published: April 2007

The idea of rank-one updates for the inverse of the Newton iteration matrix is considered in the context of solving stiff systems of ordinary differential equations. A specific and simple problem (linear, with a constant, diagonal Jacobian) and a specific and simple method (backward Euler, with constant step) are studied. A Newton iteration matrix which is in error because of a change in step size is then considered. The various resulting Newton matrices (original and updated) and the spectral radii of the corresponding error reduction matrices are computed. Two formulations of the Newton process are considered. On the whole the results are rather discouraging. The observed reductions in spectral radii as a result of the use of updates were usually only slight, unless sufficiently large numbers of updates were performed.
A disquieting output error
Authors: Knight William R.
Published: April 2007

What use to compute accurately the inverse of a matrix or the solution of a differential equation if the output routine mangles the accurate answer? No program is better than the output service which prints its results. This note reports a horrid malfunction of a particular output facility.
MACSYMA, a resource for the Navy Laboratories
Authors: Cuthill Elizabeth , Meals Kenton
Published: April 2007

A tool that would be a welcome resource to any numerical analyst is one that would provide a convenient way of performing the laborious symbolic and numerical mathematics needed in the development and testing of algorithms. MACSYMA (Project MAC's Symbolic Manipulation System) [1] at MIT is beginning to fulfill this role for the Navy Laboratory community as a result of the recently established Navy Laboratory Computer Network.
On the triangularization of arbitrary matrices
Authors: Huang C. P.
Published: April 2007

The main object of this note is to show that a matrix of order 3 can be triangularized by just one sequence of rotations. In [1] we describe a process to triangularize a matrix of order 3. The process consists of two steps. The first step is to apply a sequence of two Greenstadt's rotations [1] with pivot-pairs (1, 2) and (2, 3). This sequence of rotations shall either triangularize the matrix, or the resulting matrix becomes the exceptional form (see equation (8) of [1]). The second step of the process wants to change the matrix from the exceptional form to the non-exceptional so that the first step can resume its function again. Parlett and Wang [2] point out that it probably would take the first step an infinite sequence of rotations to bring the matrix to the exceptional form. Therefore, in order to triangularize the matrix, the process would have to apply a concatenation of infinitely many infinite sequences of rotations. Wang [2] proposes a way to eliminate this concatenation by trying to apply the second step prior to the "end" of the first step, i.e., prior to some point where the matrix is turning into the exceptional form. In this note we show that the process described in [1] does not require a concatenation of many infinite sequences of rotations, it only requires one sequence of rotations to triangularize a matrix. Here we consider only the matrix of order 3, but we believe that a similar analysis can also be applied to matrices of higher order. Throughout this note we assume that notations that are used without specification are the same notations used in [1].
The microcomputer as a tool in numerical analysis
Authors: Stewart Kris
Published: April 2007

The affordability of microcomputers makes them a practical tool for scientific computations and development of algorithms as well as a dramatic teaching aid. A package of mathematical software called SCRUNCH (1) is available to run in BASIC on moderate sized microcomputers (at least 8K and preferably 16K program space) to aid in the above tasks. SCRUNCH consists of translations of FORTRAN routines taken from three excellent sources:
Combatting the effects of underflow and overflow in determining real roots of polynomials
Authors: Linnainmaa Seppo
Published: April 2007

A new method, requiring no extended number range, is presented to prevent all harmful effects caused by both underflow and overflow when any polynomial equation with real coefficients is to be solved for real roots. Examples of polynomial equations are given having no conventional scaling possibility where replacing either overflowed numbers by the largest possible number or underflowed numbers by zero leads to badly erroneous results. The proposed method is capable to solve also these equations correctly. Also other successful methods, based on extended range of numbers, are discussed.
University Consortium for Industrial Numerical Analysis (UCINA)
Authors: McKee S.
Published: April 2007

The University Consortium for Industrial Numerical Analysis (UCINA) was formed on the 1st October 1979 with Dr. Sean McKee as the Project Coordinator. UCINA represents a collaborative effort by numerical analysts and interested applied mathematicians of the Universities of Bath, Brunel, Oxford, Reading and Imperial College, with strong support from the Division of Numerical Analysis and Computing Sciences at the National Physical Laboratory, to help with the solution of practical problems in industry and relevant research laboratories and to stimulate new and relevant research in numerical analysis in the Universities. Funding is from the Science and Engineering Research Council (SERC) for three years in the first instance. Dr. McKee has a part-time secretary, a direct line (Oxford 513035) to and from the outside world and travel and secretarial expenses.
The NAG library ordinary differential equations chapter and short term plans for its extension
Authors: Gladwell I.
Published: April 2007

We outline the contents of the ordinary differential equation (D02) chapter of the NAG library at Mark 11 paying particular attention to the aims and structure of the chapter and to the user interface. We close with a description of the additions to the chapter which are in preparation.
Proposal for a language compatible arithmetic standard
Authors: Payne Mary , Schaffert Craig , Wichmann Brian
Published: April 2007

The following proposal for an arithmetic standard has been submitted to the American National Standards Institute and the International Organization for Standardization. It is being processed by the ANSI X3T2 committee and the ISO/IEC JTC1/SC22/WG11 working group. The specifications cover both integer and floating point arithmetic.
View-based tool integration in database-centered environments
Authors: Venugopal V.
Published: April 2007

Database-centered environment architectures differ significantly from file-based architectures. Consequently they require a different set of primitives for tool support. This paper describes a form of tool composition called
cotools
which provides many of the benefits of UNIX pipes in terms of being able to reuse existing tools in tool composites, and allowing tools to operate concurrently ad incrementally on data. However, the tool language and the composition model is tailored to provide these benefits in a database-centered environment where tools do not directly communicate with each other. The effect of communication is achieved by allowing member tools in a cotool to access common data in a coordinated manner while allowing the changes made to data by one tool immediately visible to other tools in the cotool.Since
database transactions
normally maintain consistency in a database by disallowing interleaved data manipulation amongst separate applications, certain modifications to the concept of transactions are required. One of goals from a systemic point of view is to allow the benefits of tool cooperation without completely violating the transactions idea, which is a very clean mechanism for maintaining data consistency in a shared data store.
A model of data integrity
Authors: Varney W. Douglas , Unger Elizabeth A.
Published: April 2007

The Clark and Wilson model for expressing data integrity constraints is based upon the principles of segregation of duty and assures the manipulation of data only by well formed transactions. In this paper we propose a model using the Clark and Wilson principes and incorporating an attribute grammar to test if the data has integrity from a user's perspective. The definition that data either has integrity or it fails to have integrity is maintained but a set of qualities of data, e.g., age of the data are allowed to be specified by the data administrator or user. These qualities are used to ascertain whether a datum has met the specified quality.
Some thoughts on peer review of computing materials
Authors: Ash Roberta , Sim Francis M. , Anderson Ronald
Published: April 2007

It is well known that over the past decade and a half social and behavioral scientists have become heavy users of computation facilities for a variety of purposes, chiefly in data-management and measurement analyses, in statistical analysis, both descriptive and inferential, and more recently in data and process simulations. At the same time, most social scientists have been, and many will continue to be, amateurs in computational practice. In addition, the types of computation which they need (or at least, have used) are often repetitive; relative to the total volume of use by social scientists there has been little demand for computational novelty.
Machine readable documentation of social science data
Authors: Shanks J. Merrill
Published: April 2007

Mr. Chairman, like other people in the room, I believe our major purpose should be a lively discussion of alternative strategies for standardization, so I will try to be brief in presenting my own point of view.
A view of the data file access problem from the perspective of a research librarian
Authors: Krikelas James
Published: April 2007

In the 1960s, the emergence of a relatively large number of archives for machine-readable data (i.e., data libraries) gave rise to the notion that traditional university and research libraries would be forced to cope with the integration of such information into their collections. Historically, libraries have been dedicated to the gathering, processing, and storage of information and, in all but the weakest organizations, to providing active and skilled assistance in the interpretation and use of the collection. For a variety of reasons, libraries have occasionally failed to acquire new types of information, either because of inaccurate perception about the need of such material or because of some reluctance to deal with a new medium of distribution. Nonconventional information centers have developed as alternative sources of such materials. The scope and depth of the collection of such centers can be stated in relatively precise terms which describe the narrowly defined target user-group. Under these circumstances special libraries appear to respond much more rapidly to user needs, and users tend to view the center almost as an extension of one's own personal collection. As the special collection grows and the user group diversifies, the informal procedures developed for the acquisition, indexing and storage of materials begins to break down. If this evolution follows traditional patterns, personnel in data libraries will be confronted with increasing problems of storage and retrieval of information. It may be tempting to believe that these are unique difficulties requiring previously untried solutions. In actuality, there are many problems facing the data library manager that have their analogous situations and solutions in traditional libraries. It is the purpose of this paper to share a few observations about these similarities based on a preliminary investigation of the procedures and services offered at one particular data center.
Computing and our relationship to work
Authors: Goldstein Joel W.
Published: April 2007

Surveys of public attitudes toward computers suggest that, for most people, most of the time, the machines are not seen as having great importance in their lines. Yet there are developments occurring which may produce profound effects with important social consequences. It is now recognized that the automobile allowed and accelerated the development of specialized institutions, and changed residential patterns which, in turn, changed the nature and function of the family. An examination of the history of the automobile reveals that these important but indirect effects were not even hinted at (Flink, 1970). It is now time to see if it is possible to understand and anticipate the potential human impact of computation.
The development of user-oriented interactive systems
Authors: Foley James
Published: April 2007

To build effective user-oriented computer systems, we need to develop theories of how people use computer systems and process information. We also must construct user models of various sorts. We need to apply those things that we know, disseminate what we know, and do a lot of teaching. Since we haven't been doing these things very effectively thus far, our computer systems are not particularly user-oriented or people-oriented.
Evaluation of statistical program packages
Authors: Velleman Paul
Published: April 2007

I enjoyed and agree with the article on peer review of computing materials by Roberta Ash, Francis Sim, and Ronald Anderson in the last issue of the SIGSOC Bulletin. I am writing to report that a project to sponsor, collect, and publish reviews of statistical Computing software has recently begun under the auspices of the Statistical Computing Section of the American Statistical Association. The committee doing this work is chaired by Ivor Francis (358 Ives Hall, Cornell University, Ithaca, New York 14850) and Richard Heiberger (Department of Statistics and Operations Research, Wharton School, University of Pennsylvania, Philadelphia, Penn. 19104). They have issued a preliminary proposal of specific criteria for use by reviewers which I have summarized below. I will be chairing a liaison committee to facilitate communication between this group and SIGSOC. Readers with ideas and suggestions are urged to send them to me or to either of the co-chairmen.
On the need for humane rationing of interactive service
Authors: Sim Francis M. , Miller Roscoe T. , Kreider Glen D.
Published: April 2007

In a sense, our text for the next few pages is that "the meek should inherit . . . "; or, at least, if they don't get the whole earth, they deserve a fair shake in computing. Hopefully, the title we've chosen is self-explanatory; but if there were to be a subtitle, perhaps we'd choose, "A Funny Thing Happened on the Way to Interactive Computing."
Answers delayed are answers denied
Authors: Welch James S.
Published: April 2007

Modern Linear Programming (LP) models have become so large that the data management system that loads the data and reports the results requires as much attention as the selection of the optimizer. Two philosophically different approaches to LP data management are reviewed in this paper; (1) using a general purpose programming language (e.g. PL/I) and (2) using a special purpose language (perversely called "matrix generator" in the trade) designed specifically to support LP models.
MP developments on burroughs computers
Authors: Carstens David M.
Published: April 2007

Mathematical Programming Systems that are available on Burroughs Computers are described. Possible differences between these systems that use serial processing equipment and a future system that uses parallel processing equipment are considered.
Software support for combinatorial optimization
Authors: Shepherd Roger A. , Hirshfeld Dave S.
Published: April 2007

The present state of development of MPS III, Ketron's general purpose mathematical programming computer system, is summarized. Two new mixed-integer programs COMBO and BLOOD-HOUND, available within MPS III, are discussed at length. Future directions of MPS III are outlined.
Automatic reformulation of mixed and pure integer models to reduce solution time in apex IV
Authors: Oley Louis A. , Sjoquist Robert J.
Published: April 2007

Efficient model formulation rules have been established for mixed and pure integer problems to improve solution times for the branch and bound algorithm. These techniques have been implemented in the automatic model re-formulator of APEX IV. The effect of those techniques in significantly reducing solution times on several large models will be presented.
Speeding up the primal simplex algorithm on parallel computer
Authors: Kamdoum Basile
Published: April 2007

This communication considers the problem of implementing the classical primal simplex algorithm on a parallel computer. The simplex algorithm is sequential in nature but computation within each step can be accelerated using k processors; the speeding up is proportional to k.
Precision recall with user modeling (PRUM)
Authors: Piwowarski B. , Gallinari P. , Dupret G.
Published: April 2007

Standard Information Retrieval (IR) metrics are not well suited for new paradigms like XML or Web IR in which retrievable information units are document elements and/or sets of related documents. Part of the problem stems from the classical hypotheses on the user models: They do not take into account the structural or logical context of document elements or the possibility of navigation between units. This article proposes an explicit and formal user model that encompasses a large variety of user behaviors. Based on this model, we extend the probabilistic precision-recall metric to deal with the new IR paradigms.
An empirical investigation of user term feedback in text-based targeted image search
Authors: Chai Joyce Y. , Zhang Chen , Jin Rong
Published: April 2007

Text queries are natural and intuitive for users to describe their information needs. However, text-based image retrieval faces many challenges. Traditional text retrieval techniques on image descriptions have not been very successful. This is mainly due to the inconsistent textual descriptions and the discrepancies between user queries and terms in the descriptions. To investigate strategies to alleviate this vocabulary problem, this article examines the role of user term feedback in targeted image search that is based on text-based image retrieval. Term feedback refers to the feedback from a user on specific terms regarding their relevance to a target image. Previous studies have indicated the effectiveness of term feedback in interactive text retrieval. However, in our experiments on text-based image retrieval, the term feedback has not been shown to be effective. Our results indicate that, although term feedback has a positive effect by allowing users to identify more relevant terms, it also has a strong negative effect by providing more opportunities for users to specify irrelevant terms. To understand these different effects and their implications, this article further analyzes important factors that contribute to the utility of term feedback and discusses the outlook of term feedback in interactive text-based image retrieval.
Video abstraction
Authors: Truong Ba Tu , Venkatesh Svetha
Published: April 2007

The demand for various multimedia applications is rapidly increasing due to the recent advance in the computing and network infrastructure, together with the widespread use of digital video technology. Among the key elements for the success of these applications is how to effectively and efficiently manage and store a huge amount of audio visual information, while at the same time providing user-friendly access to the stored data. This has fueled a quickly evolving research area known as
video abstraction
. As the name implies, video abstraction is a mechanism for generating a short summary of a video, which can either be a sequence of stationary images (
keyframes
) or moving images (
video skims
). In terms of browsing and navigation, a good video abstract will enable the user to gain maximum information about the target video sequence in a specified time constraint or sufficient information in the minimum time. Over past years, various ideas and techniques have been proposed towards the effective abstraction of video contents. The purpose of this article is to provide a systematic classification of these works. We identify and detail, for each approach, the underlying components and how they are addressed in specific works.
A framework for software evolution in sensor networks
Authors: Koshy Joel , Pandey Raju
Published: April 2007

Wireless sensor networks (WSNs) have received considerable attention for their promising applications in diverse realms. Remote reprogrammability is an obvious need when access to deployed nodes is impossible. The main requirements of remote reprogramming mechanisms are: (i) energy and bandwidth efficiency, (ii) low latency, and (iii) security and reliability. These requirements also apply to mobile computing environments with reprogramming needs. For example, context-aware mobile devices in
smart spaces
may need to download modules dynamically, depending on services available in a given setting. Existing methods update software either through high level application scripts interpreted by suitable middleware [3], or perform true updates at the binary level [4]. The former approach allows efficient updates through the smaller code capsules afforded by the high level of abstraction. However, this approach lacks flexibility because the middleware cannot be updated. The latter approach solves this problem, but binary updates can be large, leading to costly updates in terms of energy and bandwidth requirements. This poster presents our experiences with a technique [1] to provide flexible low-cost updates, and discusses various research issues we are focusing on to enable its use within a framework for software evolution in WSNs.
Quantitative analysis for the quality of ad hoc networks
Authors: Bostelmann Henning , Roth Jörg
Published: April 2007

This paper investigates methods to measure the connection-level quality of mobile ad hoc networks. Using an exactly solvable 1-dimensional model, we derive a set of closed formulas that describe the quality of MANETs concerning connectivity, stability, and coverage. These results allow us to predict the minimum number of network nodes for a certain quality level (the "critical mass") without the need for numerical simulations.
Technical writing
Authors: Patterson Diana
Published: April 2007

I've always had trouble sorting an index, but now I have learned that the University of Waterloo's SCRIPT does it as it should.
On Scolnik's proposed polynomial-time linear programming algorithm
Authors: Gay David M.
Published: April 2007

At the Eighth International Symposium on Mathematical Programming (August 1973 at Stanford), Hugo Scolnik suggested a line of reasoning leading to an algorithm which he thought might solve the linear programming problem in polynomial time. The algorithm which Scolnik contemplated would construct an optimal basis one column at a time, in such a way that once a column is selected to be in this basis, it need never be thrown out later; after t basic columns had been selected, the algorithm would first use two rejection criteria (a) and (b) to reduce the number of candidates for the (t+1)st column and would then use a selection criterion (c) to choose one of the remaining candidates.
A PERT-CPM tutorial
Authors: Swanson H. S. , Woolsey R. E. D.
Published: April 2007

PERT and CPM, acronyms for "program evaluation and review technique" and "critical path method", respectively, are network techniques used to aid in the planning, scheduling, monitoring, and control of activities which are related to each other. For example, CPM is frequently used in the construction industry to help organize and schedule those activities which together constitute a given construction project. PERT was first used to help coordinate the activities in the development of the Polaris missle system. PERT and CPM differ from each other in that activity times are handled differently by these two closely related techniques. In using CPM, one assumes the activity times are known with certainty (deterministic activity times); PERT allows for uncertainty and statistical variation in activity times (stochastic activity times). Never the less, PERT and CPM are closely related (CPM may be a special case of PERT), and a variety of projects are subject to analysis by either technique:
(1)
(1) construction projects(2) planning and launching a new product(3) a turn around in an oil refinery (or other maintenance projects)(4) installing and debugging a computer system(5) scheduling ship construction and repairs(6) manufacture and assembly of large job-lot operations(7) missile countdown procedures(8) end-of-the month closing of accounting records(9) research and development projects
Further experiments in the formulation of integer programming problems
Authors: Wilson J. M.
Published: April 2007

Interest has been shown recently in different approaches to formulating integer programming problems. In the paper of Williams [1] five different types of problems are considered and each is formulated in two different ways. The first of these problems will be considered here, a Market Share problem, and this will be formulated in two additional ways. The two additional formulations are in fact general methods of formulating certain types of problems in (0-1) variables and so can be used on other models.
Microprogramming
Authors: Tassinari Alberto F.
Published: April 2007

Pedagogical values of microprogramming arise from the fact that it permits a thorough understanding of both computer organization and processor languages at one time, since in this discipline two fundamental topics of Computer Science, the design of logic structures and the study of symbolic languages, merge.
News and notices
Authors: Merwin R. E.
Published: April 2007

The News and Notices in this issue include reprints from recent journals. The following is a list of the items included in this section.
Notes from recent meetings
Authors: Habib Stanley
Published: April 2007

Abstracts from the meeting are presented herein. Full proceedings will be available from ACM Headquarters in early 1974.
Design considerations for microprogramming languages
Authors: Lloyd Gregory R. , van Dam Andries
Published: April 2007

The growing acceptance of user-microprogrammable computers indicates that microprogramming, as a discipline, will require development of user-oriented microprogramming support. A number of approaches (definition of sophisticated target machines, microcode assemblers, and higher level microprogramming languages) have been proposed. The issues involved in choosing support tools include the range of proposed applications, hardware parallelism (horizental or minimally encoded control vs. vertically encoded control) and constraints on performance. After reviewing some of these tradeoffs, design considerations for higher level microprogramming languages are considered. One of the most important design decisions is fixing the level of the language, defined on a continuum from symbolic assemblers, through general purpose programming languages such as PL/I. A tailored language concept is defined and illustrated, using as an example a microprogramming language for a horizontally encoded microprogrammable computer currently under development.
Support software for micro program development
Authors: Hodges Bobby C. , Edwards Andrew J.
Published: April 2007

The current and continuing needs for advanced space data processing require the critical selection and application of specially configured computer processors. This requirement generally results in unacceptable delays in software development as existing systems are typically unresponsive to required language or code generative changes. NASA/MSFC is attacking the problem of application dependent processor configuration with the MSFC conception and development of the Space Ultrareliable Modular Compuer (SUMC). The SUMC provides for tailored architecture through reconfigurable hardware design and flexible software development via microprogramming. Adaptable system and subsystem processors provide a modular systematic solution for achieving application responsive goals at both the hardware and software levels.
Concepts of high-level-language computer architecture
Authors: Chu Yaohan
Published: April 2007

High-level-language (HLL) computer architecture refers to those architecture which can accept one or more high-level languages (such as Fortran, Alogl, Snobol, etc.). This paper classifies the HLL computer architecture into four types (von Neumann architecture, syntax-oriented architecture, indirect execution architecture, and direct execution architecture) based on the criterion of proximity in lexicality, syntax and semantics between the high-level language and the machine language. It then introduce es concepts of these high-level-language architecture. A simple example is employed to illustrate the differences among these four types of architecture.
A microprogramming strategy for HLL interpretation
Authors: Petit J. , Litaize D. , Lecussan B. , Sansonnet J. P.
Published: April 2007

The design of a processor suited for direct interpretation of any high level language is presented..
Linear work suffix array construction
Authors: Kärkkäinen Juha , Sanders Peter , Burkhardt Stefan
Published: April 2007

Suffix trees and suffix arrays are widely used and largely interchangeable index structures on strings and sequences. Practitioners prefer suffix arrays due to their simplicity and space efficiency while theoreticians use suffix trees due to linear-time construction algorithms and more explicit structure. We narrow this gap between theory and practice with a simple linear-time construction algorithm for suffix arrays. The simplicity is demonstrated with a C++ implementation of 50 effective lines of code. The algorithm is called DC3, which stems from the central underlying concept of
difference cover
. This view leads to a generalized algorithm, DC, that allows a space-efficient implementation and, moreover, supports the choice of a space--time tradeoff. For any
v
∈ [1,
√n
], it runs in O(
vn
) time using O(
n
/
√v
) space in addition to the input string and the suffix array. We also present variants of the algorithm for several parallel and hierarchical memory models of computation. The algorithms for BSP and EREW-PRAM models are asymptotically faster than all previous suffix tree or array construction algorithms.
The effects of online advertising
Authors: McCoy Scott , Everard Andrea , Polak Peter , Galletta Dennis F.
Published: April 2007

Consumers' first impressions (and loyalties) are made in the opening moments of a Web site visit and the degree to which that visit may be intruded by pop-ups, pop-unders, and banner ads.
Using live projects without pain
Authors: Chase J. D. , Oakes Ed , Ramsey Sean
Published: April 2007

It is well understood and has been well documented that there is much to gain by using live projects, those that serve a real client with a real problem to solve, in the computer science classroom. However the use of live projects has always come with a variety of obstacles including providing support for the project once it is complete and limiting the scope of a project to the context of a single term. This paper describes the development of the Small Project Support Center at Radford University that has been designed to eliminate these obstacles.
Investigating the viability of mental models held by novice programmers
Authors: Ma Linxiao , Ferguson John , Roper Marc , Wood Murray
Published: April 2007

This paper describes an investigation into the viability of mental models used by novice programmers at the end of a first year Java programming course. The qualitative findings identify the range of mental models of value and reference assignment held by the participants. The quantitative analysis reveals that approximately one third of students held
non-viable
mental models of value assignment and only 17% of students held a
viable
mental model of reference assignment. Further, in terms of a comparison between the participants' mental models and their performance in in-course assessments and final examination, it was found that students with viable mental models performed significantly better than those with non-viable models. These findings are used to propose a more "constructivist" approach to teaching programming based on the integration of "cognitive conflict" and program visualisation.
Zoned-RAID
Authors: Kim Seon Ho , Zhu Hong , Zimmermann Roger
Published: April 2007

The RAID (Redundant Array of Inexpensive Disks) system has been widely used in practical storage applications for better performance, cost effectiveness, and reliability. This study proposes a novel variant of RAID named Zoned-RAID (Z-RAID). Z-RAID improves the performance of traditional RAID by utilizing the zoning property of modern disks which provides multiple zones with different data transfer rates within a disk. Z-RAID levels 1, 5, and 6 are introduced to enhance the effective data transfer rate of RAID levels 1, 5, and 6, respectively, by constraining the placement of data blocks in multizone disks. We apply the Z-RAID to a practical and popular application, streaming media server, that requires a high-data transfer rate as well as a high reliability. The analytical and experimental results demonstrate the superiority of Z-RAID to conventional RAID. Z-RAID provides a higher effective data transfer rate in normal mode with no disadvantage. In the presence of a disk failure, Z-RAID still performs as well as RAID.