ppxscal/embedding_network huggingface dataset:
Strongly Regular Semi-Cayley Graphs
Authors: Marialuisa J. De Resmini, Dieter Jungnickel
Venue: Journal of Algebraic Combinatorics: An International Journal (1992)

We consider strongly regular graphs &Gamma; &equals; (V, E) on an even number, say 2n, of vertices which admit an automorphism group G of order n which has two orbits on V. Such graphs will be called strongly regular semi-Cayley graphs. For instance, the Petersen graph, the Hoffman&ndash;Singleton graph, and the triangular graphs T(q) with q &equiv; 5 mod 8 provide examples which cannot be obtained as Cayley graphs. We give a representation of strongly regular semi-Cayley graphs in terms of suitable triples of elements in the group ring ZG. By applying characters of G, this approach allows us to obtain interesting nonexistence results if G is Abelian, in particular, if G is cyclic. For instance, if G is cyclic and n is odd, then all examples must have parameters of the form 2n &equals; 4s2 + 4s + 2, k &equals; 2s2 + s, &lambda; &equals; s2 &minus; 1, and &mu; &equals; s2&semi; examples are known only for s &equals; 1, 2, and 4 (together with a noncyclic example for s &equals; 3). We also apply our results to obtain new conditions for the existence of strongly regular Cayley graphs on an even number of vertices when the underlying group H has an Abelian normal subgroup of index 2. In particular, we show the nonexistence of nontrivial strongly regular Cayley graphs over dihedral and generalized quaternion groups, as well as over two series of non-Abelian 2-groups. Up to now these have been the only general nonexistence results for strongly regular Cayley graphs over non-Abelian groups&semi; only the first of these cases was previously known.
Skills in an environment of turbulence: a survey of information systems professionals in New Zealand
Authors: D. John Monin, Philip J. Dewe
Venue: Proceedings of the 1994 computer personnel research conference on Reinventing IS : managing information technology in changing organizations: managing information technology in changing organizations (1994)

Based on a survey of 443 members of the New Zealand Computer Society, this study examines whether the skills requirements for information systems professionals have changed in the turbulent economic environment New Zealand has experienced during the last decade. Respondents to the questionnaire were asked to rate the importance of thirty-five skill items during the period they have been working under their present job designation. Although this exploratory study is not restricted to the last decade, the research expectations are that there has been a definite shift in the skills requirement. The focus is on the categorization of the skills as business-related or technology-related, this being the distinction traditionally accepted by most researchers to date. The results, however, of this study indicate a blurring of such a dichotomy, due possibly to a perception by the more experienced members of the profession that there has been a pronounced swing towards a requirement for more business-related skills. This research suggests a model to cater for this phenomenon, and a more comprehensive set of skill items for further research.
HRM practices in information technology management
Authors: Ernest Jordan, Alma M. Whiteley
Venue: Proceedings of the 1994 computer personnel research conference on Reinventing IS : managing information technology in changing organizations: managing information technology in changing organizations (1994)

This paper concerns the specific problem of the critical levels of staff turnover in the information technology (IT) area in Hong Kong. The aim is to give advice to improve the management of IT personnel. IT management practices are compared with theories from human resource management. As the theories are mostly developed in a Western context, a grounded approach has been taken. An in-depth study of programmers and analyst programmers in Hong Kong was carried out at the time of a crisis in labour turnover. The level of crisis enabled this study to find underlying factors that may normally be more hidden. A low level of attachment to the organisation was found, with stronger ties towards the profession and professional development. There was also an apparent difference in the attitudes and practices of group work.
Iterative development/OO: the bottom line
Authors: J. O. Coplien, Susana Hutz, Brent Marykuca
Venue: ACM SIGPLAN OOPS Messenger (1993)

A combined workshop drawing on the faculties of the established &ldquo;The Bottom Line: Using Object-Oriented Development in the Commercial Environment&rdquo; workshop and the new &ldquo;Development Processes for Use of the Object Paradigm&rdquo; covered issues of process, architecture, and tool support for iterative development. Keynote talks described: &bull; far-reaching multidimensional development methods &bull;the problems of semantic coupling between objects &bull;a highly iterative development project using a symbolic language &bull;a pioneering development where high-level management was given a traditional view of development, while first-level management enjoyed the benefits of more loosely structured iteration &bull;the use of formal specifications as a universal development tool facilitating compactness and analysis Discussion on architecture, tools and reuse, and management techniques followed. Key areas of consensus included the multidimensionality of architecture, the inadequacy of class models alone to encapsulate change, the importance of tool support, and the need for local standards such as &ldquo;software backplanes.&rdquo;
Handling control
Authors: Dorai Sitaram
Venue: Proceedings of the ACM SIGPLAN 1993 conference on Programming language design and implementation (1993)

Non-local control transfer and exception handling have a long tradition in higher-order programming languages such as Common Lisp, Scheme and ML. However, each language stops short of providing a full and complementary approach&mdash;control handling is provided only if the corresponding control operator is first-order. In this work, we describe handlers in a higher-order control setting. We invoke our earlier theoretical result that all denotational models of control languages invariably include capabilities that handle control. These capabilities, when incorporated into the language, form an elegant and powerful higher-order generalization of the first-order exception-handling mechanism.
On seamless prototyping
Authors: Hal Berghel
Venue: ACM SIGICE Bulletin (1994)

With the advent of visual programming environments and visual programming languages, the face of software prototyping has changed forever. Modern software interfaces have a look-and-feel which was inconceivable to most practitioners just a decade ago, and this rapid advance has been fueled by imaginative research in human factors and computer graphics. However, we view this as a mixed blessing for (a) these advances have distracted researchers from more pressing, fundamental methodological concerns, and (b) the sophisticated interface technology encourages "facade" prototyping. Many modern prototypes are, s a result, shallow if not hollow and of little utility beyond what could be accomplished more easily and more inexpensively with presentation software.In this paper we encourage practitioners to consider more widespread use of a seamless prototyping strategy. Seamless prototyping is characterized by the closeness with which the prototype resembles the final product. We argue that this proximity may be achieved by extending the prototype development time and delaying its initiation and a continuous, gradual development process. While a seamless approach to prototyping will require more time and energy than less robust alternatives the reward follows from the fact that the prototype is faithful to the vision of the end result and that little development effort is wasted. We then illustrate seamless prototyping with examples from our own experience.
Computational geometry
Authors: Joseph O'Rourke
Venue: ACM SIGACT News (1994)

The class of n2-hard geometric problems is described, with special concentration on detecting collinearities among a set of points in the plane.
Balanced Cooperative Modeling
Authors: Katharina Morik
Venue: Machine Learning (1993)

Machine learning techniques are often used for supporting a knowledge engineer in constructing a model of part of the world. Different learning algorithms contribute to different tasks within the modeling process. Integrating several learning algorithms into one system allows it to support several modeling tasks within the same framework. In this article, we focus on the distribution of work between several learning algorithms on the one hand and the user on the other hand. The approach followed by the MOBAL system is that of balanced cooperation, i.e., each modeling task can be done by the user or by a learning tool of the system. The MOBAL system is described in detail. We discuss the principle of mutli-functionality of one representation for the balanced use by learning algorithms and users.
Breaking Substitution Cyphers Using Stochastic Automata
Authors: B. J. Oommen, J. R. Zgierski
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1993)

Let Lambda be a finite plaintext alphabet and V be a cypher alphabet with the same cardinality as Lambda . In all one-to-one substitution cyphers, there exists the property that each element in V maps onto exactly one element in Lambda and vice versa. This mapping of V onto Lambda is represented by a function T*, which maps any v in V onto some lambda in Lambda (i.e., T*(v)= lambda ). The problem of learning the mapping of T* (or its inverse (T*)/sup -1/) by processing a sequence of cypher text is discussed. The fastest reported method to achieve this is a relaxation scheme that utilizes the statistical information contained in the unigrams and trigrams of the plaintext language. A new learning automaton solution to the problem called the cypher learning automaton (CLA) is given. The proposed scheme is fast, and the advantages of the scheme in terms of time and space requirements over the relaxation method have been listed. Simulation results comparing both cypher-breaking techniques are presented.
An object-oriented environment for specification and concurrent execution of genetic algorithms
Authors: L. Lemarchand, A. Plantec, B. Pottier, S. Zanati
Venue: ACM SIGPLAN OOPS Messenger (1993)

Genetic algorithms (GA) mimic natural reproduction to search for complex problem solutions. Their principles are shortly explained. A point of interest is the regular and repetititve structure of computation involving communication, data exchanges, and control phases. Interaction with presentation and analysis tools is also a requirement. This make sense for the definition of a general framework allowing fast building of parallel applications in an object-oriented system. A GA workbench is developed using the Smalltalk-80 system with parallel machine code generation in mind.
Semantics for communication primitives in a polymorphic language
Authors: Atsushi Ohori, Kazuhiko Kato
Venue: Proceedings of the 20th ACM SIGPLAN-SIGACT symposium on Principles of programming languages (1993)

We propose a method to extend an ML-style polymorphic language with transparent communication primitives, and give their precise operational semantics. These primitives allow any polymorphic programs definable in ML to be used remotely in a manner completely transparent to the programmer. Furthermore, communicating programs may be based on different architecture and use different data representations. We define a polymorphic functional calculus with transparent communication primitives, which we call dML, as an extension of Damas and Milner's proof system for ML. We then develop an algorithm to translate dML to a &ldquo;core&rdquo; language containing only low-level communication primitives that are readily implementable in most of distributed environments. To establish the type safety of communicating programs, we define an operational semantics of the core language and prove that the polymorphic type system of dML is sound with respect to the operational semantics of the translated terms of the core language.
A library for discrete event simulations
Authors: M. A. Pollatschek
Venue: ACM SIGSMALL/PC Notes (1993)

Discrete event simulation models development of processes evolving in time such as inventory or service stations, where change in the state (inventory level or number of waiting customers) are caused by events occurring at discrete points of time, such as the arrival of a new customer. The model is a program which imitates the process and collects statistics from which conclusions can be drawn. For example, what is the impact of a given policy on inventory level or of priority rules on queue size? Dedicated languages have been developed for writing simulation programs such as GPSS, Simscript, SLAM, SIMAN. However, it is possible to extend ordinary C (and of course C++) by an appropriate library providing nearly all the services that dedicated languages offer. In the following we give a short tutorial on simulation using a simple problem, coding it in C and calling functions from the library to demonstrate that the library approach is a respectful alternative to dedicated languages. We also discuss shortly how to fit the C library to various environments and review two real life problems where the library was successfully used. (Similar libraries are available for compiled BASIC, Pascal and FORTRAN, all for a PC.)
Efficient factorization of linear ODE's
Authors: Fritz Schwarz
Venue: ACM SIGSAM Bulletin (1994)

Factorization and testing for irreducibility has turned out to be one of the most important algorithms for handling linear ode's. The main hindrance for applying it is its tremendeous complexity originating to a large extent from solving certain Riccati equations which occur during the factorization. The solution procedure for these Riccati equations is much more manageable if it is subdivided into two major parts. At first so called solution candidates are determined each of which depends only on the parameters of a single irreducible denominator or the behavior at infinity. In a second step it is tried to complete each candidate into a genuine solution of the Riccati equation, possibly including an unspecified number of additional first order poles. Furthermore a scheme is proposed for running the factorization procedure in parallel on a two-processor machine in which possible factors are searched for both from the right and the left at the same time.
Parallel eigenanalysis for nested grids
Authors: Giorgio Pini, Giuseppe Gambolati
Venue: Proceedings of the 7th international conference on Supercomputing (1993)

A new method (NI-DACG) for the partial eigensolution of large sparse symmetric FE eigen problems is presented. NI-DACG relies on the optimization of Rayleigh quotients in successively deflated subspaces by a preconditioned conjugate gradient technique and uses a multiple grid type approach to assess an improved eigenvector estimate on nested FE grids on which the solution to the continuous eigenproblem is sought. NIDACG is implemented on the CRAY Y-MP supercomputer making use of vectorization and/or parallelization with two and four processors. Results relative to the calculation of the 50 smallest eigenpairs for two representative sample problems show a gain in CPU time that exceeds one order of magnitude with respect to the scalar implementation of NI-DACG and emphasize the promising features of this technique for the partial eigenanalysis on supercomputers.
Anonymous routine-texts: an orthogonal approach to block objects
Authors: Otto Stolz
Venue: ACM SIGPLAN Notices (1993)

Hanspeter M ouml;ssenb ouml;ck has proposed [7] a language construct for treating statement sequences as block objects that can be passed to procedures as parameters. As these blocks are nothing else but parameterless procedures, a more orthogonal solution to M ouml;ssenb ouml;ck's set of problems has long been available: in the programming language Algol 68, a routine-text can be specified, anonymously, in the place of an argument.The present contribution presents M ouml;ssenb ouml;ck's example in Algol 68 notation, and demonstrates the versatility of anonymous routine-texts by transforming the given example to a neater solution.
People, Organizations, and Process Improvement
Authors: Dewayne E. Perry, Nancy Staudenmayer Lawrence G. Votta
Venue: IEEE Software (1994)

In their efforts to determine how technology affects the software development process, researchers often overlook organizational and social issues. The authors report on two experiments to discover how developers spend their time. They describe how noncoding activities can use up development time and how even a reluctance to use e-mail can influence the development process. The first experiment was to see how programmers thought they spent their time by having them fill out a modified time card reporting their activities, which we called a time diary. In the second experiment, we used direct observation to calibrate and validate the use of time diaries, which helped us evaluate how time was actually being used.
Static analysis of Ada programs
Authors: Daniel H. Ehrenfried
Venue: ACM SIGAda Ada Letters (1994)

The upcoming standardization of the Ada Semantic Interface Specification (ASIS) makes possible the development of portable static analysis tools for Ada programs. This paper introduces this class of back-end CASE tools, lists their capabilities, and describes how they can be used during the software-development process to increase overall software quality. The description is based on one such tool: the Ada Analyzer developed by Little Tree Consulting.
On the complexity of the parity argument and other inefficient proofs of existence
Authors: Christos H. Papadimitriou
Venue: Journal of Computer and System Sciences (1994)

We define several new complexity classes of search problems, ''between'' the classes FP and FNP. These new classes are contained, along with factoring, and the class PLS, in the class TFNP of search problems in FNP that always have a witness. A problem in each of these new classes is defined in terms of an implicitly given, exponentially large graph. The existence of the solution sought is established via a simple graph-theoretic argument with an inefficiently constructive proof; for example, PLS can be thought of as corresponding to the lemma ''every dag has a sink.'' The new classes, are based on lemmata such as ''every graph has an even number of odd-degree nodes.'' They contain several important problems for which no polynomial time algorithm is presently known, including the computational versions of Sperner's lemma, Brouwer's fixpoint theorem, Chevalley's theorem, and the Borsuk-Ulam theorem, the linear complementarity problem for P-matrices, finding a mixed equilibrium in a non-zero sum game, finding a second Hamilton circuit in a Hamiltonian cubic graph, a second Hamiltonian decomposition in a quartic graph, and others. Some of these problems are shown to be complete.
Implementation-based analysis and testing of Prolog programs
Authors: B. Belli, O. Jack
Venue: Proceedings of the 1993 ACM SIGSOFT international symposium on Software testing and analysis (1993)

In this paper, we describe the PROTest II (PROlog Test Environment, Version 2) system to test logic programs in an interactive support environment. Logic programs are augmented with declarative information about the types and modes of the arguments of a predicate. Modes correspond to in, out, and in-out parameters. With this information PROTest II statically checks the types of Prolog programs, generates test cases, executes Prolog programs, and produces reports summarizing results including information about new test coverage metrics. Thus, PROTest II enables both static analysis and dynamic testing uniformly using a Prolog-based test language DTL/1. The strength of PROTest II stems from its idea of defining coverage in real logic programming terms, rather than adapting imperative programming ideas.
A binary algorithm for the Jacobi symbol
Authors: Jeffrey Shallit, Jonathan Sorenson
Venue: ACM SIGSAM Bulletin (1993)

We present a new algorithm to compute the Jacobi symbol, based on Stein's binary algorithm for the greatest common divisor, and we determine the worst-case behavior of this algorithm. Our implementation of the algorithm runs approximately 7--25% faster than traditional methods on inputs of size 100--1000 decimal digits.
An efficient implementation scheme of concurrent object-oriented languages on stock multicomputers
Authors: Kenjiro Taura, Satoshi Matsuoka, Akinori Yonezawa
Venue: Proceedings of the fourth ACM SIGPLAN symposium on Principles and practice of parallel programming (1993)

Several novel techniques for efficient implementtion of concurrent object-oriented languages on general purpose, stock multicomputers are presented. These techniques have been developed in implementing our concurrent object-oriented language ABCL on a Fujitsu Laboratory's experimental multicomputer AP1000 consisting of 512 SPARC chips. The propsed intra-node scheduling mechanism reduces the cost of local message passing. The cost of intra-node asynchronous message passing is about 20 SPARC instructions in the bst case, including locality checking, dynamic method lookup, and scheduling. The minimum latency of asynchronous internode message passing is about 9&mgr;s, or about 120 instructions, employing the self-dispatching mechanism independently proposed by Eicken et al. A large scale benchmark which involves 9,000,000 message passings shows 440 times speedup on the 512 nodes system compared to the sequential version of the same algorithm. We rely on simple hardware support for message passing and use no specialized architectural supports for object-oriented computing. Thus, we are able to enjoy the benefits of future progress in standard processor technology. Our result shows that concurrent object-oriented languages can be implemented efficiently on conventional multicomputers.
On Schur's Q-functions and the Primitive Idempotents of a Commutative Hecke Algebra
Authors: John R. Stembridge
Venue: Journal of Algebraic Combinatorics: An International Journal (1992)

Let Bn denote the centralizer of a fixed-point free involution in the symmetric group S2n. Each of the four one-dimensional representations of Bn induces a multiplicity-free representation of S2n, and thus the corresponding Hecke algebra is commutative in each case. We prove that in two of the cases, the primitive idempotents can be obtained from the power-sum expansion of Schur's Q-functions, from which follows the surprising corollary that the character tables of these two Hecke algebras are, aside from scalar multiples, the same as the nontrivial part of the character table of the spin representations of Sn.