ppxscal/embedding_network huggingface dataset:
A priori inequalities for the Euclidean traveling salesman
Authors: Timothy Law Snyder, J. Michael Steele
Venue: Proceedings of the eighth annual symposium on Computational geometry (1992)

It is proved that there are constants c1, c2, and c3 such that for any set S of n points in the unit square and for any minimum-lengths of T of S (1) the sum of squares of the edge lengths of T is bounded by c1 log n, (2) the sum of edge lengths of any subset E of T is bounded by c2|E|1/2, and (3) the number of edges having length t or greater in T is at most c3/t2. The second and third bounds are independent of the number of points in S, as well as their locations. Extensions to dimensions d>2 are also sketched. The presence of the logarithmic term in (1) is engaging because such a term is not needed in the case of the minimum spanning tree and several analogous problems, and, furthermore, we know that there always exists some tour of S (which perhaps does not have minimal length) for which the sum of squared edges is bounded independently of n.
A formal specification tool for distributed office systems
Authors: Hossein Saiedian, Elizabeth A. Unger
Venue: ACM SIGSMALL/PC Notes (1991)

Office Automation (OA) is an approach to the new way of handling information in an office and as such there is no universally accepted definition for it. We have defined it as the body of knowledge that is concerned with the analysis, design, implementation, efficiency and application of processes that transform information in an office. The trend toward full office automation has been the result of dramatic fall in the cost of computer hardware and technological advances in the field of communications. The result has been to make interconnected computer systems and computer networks a viable and cost effective solution to many problems in the offices.The purpose of this paper is to address some of the important issues surrounding the construction of office systems and to describe the design principles of a formal specification methodology for office systems. In particular, we discuss the desired properties of a computational model upon which a specification methodology for office systems should be based. An overview of ABSL, an object-oriented specification methodology that we are currently developing is presented and the main ideas in this methodology are described.
A performance analysis of alternative multi-attribute declustering strategies
Authors: Shahram Ghandeharizadeh, David J. DeWitt, Waheed Qureshi
Venue: Proceedings of the 1992 ACM SIGMOD international conference on Management of data (1992)

During the past decade, parallel database systems have gained increased popularity due to their high performance, scalability and availability characteristics. With the predicted future database sizes and the complexity of queries, the scalability of these systems to hundreds and thousands of processors is essential for satisfying the projected demand. Several studies have repeatedly demonstrated that both the performance and scalability of a paralel database system is contingent on the physical layout of data across the processors of the system. If the data is not declustered properly, the execution of an operator might waste resources, reducing the overall processing capability of the system. With earlier, single attribute declustering strategies, such as those found in Tandem, Teradata, Gamma, and Bubba parallel database systems, a selection query including a range predicate on any attribute other than the partitioning attribute must be sent to all processors containing tuples of the relation. By directing a query with minimal resource requirements to processors that contain no relevant tuples, the system wastes CPU cycles, communication bandwidth, and I/O bandwidth, reducing its overall processing capability. As a solution, several multi-attribute declustering strategies have been proposed. However, the performance of these declustering techniques have not previously been compared to one another nor with a single attribute partitioning strategy. This paper, compares the performance of Multi-Attribute GrId deClustering (MAGIC) strategy and Bubba's Extended Range Declustering (BERD) strategy with one another and with the range partitioning strategy. Our results indicate that MAGIC outperforms both range and BERD in all experiments conducted in this study.
Computing a sweeping-plane in regular (¿general¿) position: a numerical and a symbolic solution
Authors: Walter Nef, Peter-Michael Schmidt
Venue: Journal of Symbolic Computation (1990)

During the last approximately 12 years, sweeping-plane techniques in a linear space @?^d have become an important tool in computational geometry. They are characterized by a hyperplane moving through (''sweeping'') the space. It ''stops'' when it meets certain transition points, in order to collect local information as a contribution to the final result. Usually the movement is a uniform translation: The ''sweeping-plane'' is g^-^1(@t) (@t the time), where g: @?^d ->@? is a non-constant linear mapping. Typical applications are:(i)Find all intersections of finitely many line segments in a plane; (ii)Solution of the closest pair problem; (iii)Computation of the volume or of the Euler-characteristic of a d-dimensional polyhedron. In most cases these techniques require a family of parallel hyperplanes g^-^1(@t) in ''regular'' (or ''general'') position with respect to a finite number of points x"l, and/or planes N"k. This means that (x"l) @?. With n the number of points and planes we first present a numerical solution, allowing the computation of the coefficients of g in time O(n . log n). This solution has the disadvantage to require that the points x^l and the planes N^k are known in advance. As this condition is not met in all cases, we present a second, symbolic solution, looking at the coefficients of g as undetermined real variables. Instead of assigning numerical values to these variables we ask them to satisfy certain order relations. This symbolic method does not require the points and planes to be known in advance.
The implementation of a model-based belief revision system
Authors: Timothy S. C. Chou, Marianne Winslett
Venue: ACM SIGART Bulletin (1991)

In this paper, we briefly describe Immortal, an implementation of a model-based belief revision system. We present our motivation for building Immortal, describe its basic components and properties, and discuss our method of evaluating Immortal.
Improved approximations for the Steiner tree problem
Authors: Piotr Berman, Viswanathan Ramaiyer
Venue: Proceedings of the third annual ACM-SIAM symposium on Discrete algorithms (1992)

For a set S contained in a metric space, a Steiner tree of S is a tree that connects the points in S. Finding a minimum cost Steiner tree is an NP-hard problem in euclidean and rectilinear metrics as well as in graphs. We give an approximation algorithm and show that the worst-case ratio of the cost of our solutions to the optimal cost is better than previously known ratios in graphs, and in rectilinear metric on the plane. Our method offers a trade-off between the running time and the ratio; on one hand it always allows to improve the ratio, on the other it allows to obtain previously known ratios with much greater efficiency. We use properties of optimal rectilinear Steiner trees to obtain significantly better ratio and running time in rectilinear metric.
Applying Zen principles in an introductory programming course
Authors: John Dalbey
Venue: ACM SIGCSE Bulletin (1991)

The word "zen" often conjures up images of robed and shaven headed monks sitting in lotus position in a meditation hall in a japanese monastery. For most people it is hard to reconcile this image with that of modern computer technology. But in my experience as a teacher of computer programming I have found that certain zen principles can be very valuable for people learning about computers.Despite its "philosophical" or "abstract" reputation, zen is actually a practice aimed at helping people cope with everyday life. In a sense it is anti-philosophical because it emphasizes actions not words. Historically, zen was practiced in the context of very pragmatic and technical skills such as archery and swordsmanship. The discipline had specific exercises aimed at improving one's technical skills while simultaneously providing opportunity for a kind of spiritual growth. While programming a computer is a cognitive skill instead of a physical skill, zen principles still have important application to the psychology of learning.
The Design and Implementation of an ASN.1-C Compiler
Authors: Gerald W. Neufeld, Yueli Yang
Venue: IEEE Transactions on Software Engineering (1990)

Abstract syntax notation one (ASN.1) has been widely used in international standard specification: its transfer-syntax, the basic encoding rules (BER), is used as the external data representation. A BER implementation called the ED library is presented. The ED library includes a number of encoding and decoding routines that may be used as primitive functions to compose encoders and decoders for arbitrarily complicated ASN.1 data types. Based on the ED library an ASN.1-C compiler, called CASN1, is designed and implemented to free the protocol implementers from the arduous work of translating protocol-defined data-types and constructing their encoders and decoders. Given an ASN.1 protocol specification, CASN1 automatically translates the input ASN.1 modules into C and generates the BER encoders and decoders for the protocol defined data-types. The CASN1 design principles, user interface, and some example applications are discussed. The performance of the ED library and generated CASN1 code is also measured and discussed.
The Design of a Microsupercomputer
Authors: Trevor N. Mudge, Richard B. Brown, William P. Birmingham, Jeffrey A. Dykstra, Ayman I. Kayssi, Ronald J. Lomax, Oyekunle A. Olukotun, Karem A. Sakallah, Raymond A. Milano
Venue: Computer (1991)

A description is given of work to develop a prototype microcomputer that will realize the best of both the supercomputer and the microprocessor traditions. It does so by using GaAs MESFET enhancement/depletion direct-coupled FET logic, a high-speed technology that has good integration density, and state-of-the-art packaging technology to prevent chip crossings from dominating the overall speed of the system. The focus of the research reported is the relationship between hardware implementations and emerging technologies. The MIPS Computer Systems instruction set was implemented to bound the architectural options and to eliminate the need to develop compilers and operating systems. Efforts are concentrated on developing the processor and cache. The resulting system will be a general-purpose computer that runs a conventional Unix environment and supports standard programming languages and networking protocols. The machine will significantly accelerate execution of the existing large base of application software.
Synthesizing a Protocol Converter From Executable Protocol Traces
Authors: Murali Rajagopal, Raymond E. Miller
Venue: IEEE Transactions on Computers (1991)

Communicating finite state machines (CFSM's) with FIFO (first in, first out) queues are used to model a protocol converter. A protocol conversion algorithm is developed and presented for the CSFM model of the protocols A and B. A converter H for protocols A=(A/sub 0/, A/sub 1/) and B=(B/sub 0/, B/sub 1/) is viewed as a black box such that H is between sender A/sub 0/ and receiver B/sub 1/. This gives a resulting protocol X=(A/sub 0/, H, B/sub 1/). The conversion algorithm requires a specification of the message relationships between the messages of protocols A and B. It is assumed that protocols A and B have the required progress properties. The algorithm includes a search for related messages from the two protocols in an FIFO from a composite space formed by a Cartesian cross-product of state spaces A/sub 1/ and B/sub 0/. The search produces finite-length traces which are combined to form a state machine H, which is examined for freedom from unspecified receptions, deadlocks, and livelocks. A protocol conversion example demonstrates the applicability of the algorithm.
Cognitive issues in representing design reasoning as hypertext
Authors: Simon Shum
Venue: ACM SIGCHI Bulletin (1991)

Hypertext offers powerful facilities for representing and manipulating structure, but the cognitive task of parsing ideas into discrete chunks can be intrusive. This summary describes ongoing work looking at the use of semi-formal notations for representing design reasoning. One experiment highlighted a number of cognitive overheads in using the notation, but a subsequent study is indicating that with training, the notation can be used unobtrusively by computer scientists to record reasoning during design problem solving.
A distributed, decision-theoretic control system for a mobile robot
Authors: Gary H. Ogasawara
Venue: ACM SIGART Bulletin (1991)

A model is described that divides an agent architecture into five components (percepts, decomposition, strategies, arbitration, actions). Using this model and a decision-theoretic perspective on the agent's behavior, the resultant agent is both flexible and rational. A mobile robot control system that uses the agent architecture model is described in some depth. The mobile robot operates in a simulated, 2-D environment with fixed and moving obstacles and a limited and noisy vision sensor. A formal, comparative analysis of agent architecture classes concludes this paper.
Introduction to the proposed standard for the elementary functions in Ada
Authors: Kenneth W. Dritz
Venue: ACM SIGAda Ada Letters (1991)

Since the conclusion of its three-year development period in 1989, the proposed Standard fora Generic Package of Elementary Functions for Ada has been working its way through a hierarchy of committees towards achieving the status of a secondary ISO standard in the Ada area. This article introduces the contents of the proposed standard and discusses some of the decisions that influenced it.
Automatic determination of recommended test combinations for Ada compilers
Authors: James S. Marr, Patricia K. Lawlis
Venue: Proceedings of the eighth annual Washington Ada symposium summer SIGAda meeting on Ada: software: foundation for competitveness (1991)

Ada compilers are validated using the Ada Compiler Validation Capability (ACVC) test suite, containing over 4000 individual test programs. Each test program focuses, to the extent possible, on a single language feature. Despite the advantages of this &ldquo;atomic testing&rdquo; methodology, it is often the unexpected interactions between language features that result in compilation problems. This research investigated techniques to automatically identify recommended combinations of Ada languge features for compiler testing. A prototype program was developed to analyze the Ada language grammar specification and generate a list of recommended combinations of features to be tested. The output from this program will be used within the Ada Features Identification System (AFIS), a configuration management tool currently under development for the ACVC test suite. The prototype uses an annotated Ada language grammar to drive a test case generator. The generated combinations of Ada features are analyzed to select the combinations to be tested. While the skill and intuition of the compiler tester are eseential to the annotation of the Ada grammar, the prototype demonstrated that automated support tools can be used to identify recommended combinations for Ada compiler testing.
Context: in the eyes of users and in computer systems
Authors: Helen Maskery, Jon Meads
Venue: ACM SIGCHI Bulletin (1992)

This is the report of a workshop on context held at CHI '89. It describes the workshop and contains a summary of the main results which were agreed to by all workshop participants. The bulk of the report is provided by the three 'special groups', whose discussions filled most of the workshop's second day.
ESA&mdash;an expert supported OOA method and tool
Authors: Harald Schaschinger
Venue: ACM SIGSOFT Software Engineering Notes (1992)

Although this paper deals with object-oriented software development in general, the focus is definitely set on object-oriented analysis (OOA). After a short comparison of the most important OOA approaches, a new one will be derived. This approach is evolutionary, non-domain specific and starts at the definition of a software system. Based on this approach there will be a presentation of an expert supported OOA tool (ESA), which supports an analyst starting at the collection of the requirements through the analysis of an object-oriented system up to a preliminary high-level design. Both the method and the tool are conceived for the needs of practitioners.
Constructing normal bases in finite fields
Authors: Joachim von zur Gathen, Mark Giesbrecht
Venue: Journal of Symbolic Computation (1990)

An efficient probabilistic algorithm to find a normal basis in a finite field is presented. It can, in fact, find an element of arbitrary prescribed additive order. It is based on a density estimate for normal elements. A similar estimate yields a probabilistic polynomial-time reduction from finding primitive normal elements to finding primitive elements.
Application of nested arrays to databases for engineering design
Authors: Yehonathan Hazony
Venue: ACM SIGAPL APL Quote Quad (1991)

A major problem facing the manufacturing industry in its quest for improved productivity is the integration of Computer-Aided-Design (CAD) and Computer-Aided-Manufacture (CAM) to form systems for "seamless design-to-manufacture" (SDTM). This article describes the use of APL2 to build such an integrated system, as opposed to trying to integrate existing systems which are commercially available. The main advantages offered by APL2 are due to the combination of extensive database services, provided by nested arrays in a large workspace, and the accessibility of such data to a rich set of sophisticated mathematical tools. An "Expert-System-Generator" (ESG[1]), built in APL2, makes it possible to build a customized SDTM system which circumvents many of the problems associated with the task of integration of separate commercial systems.
Comprehensions, a query notation for DBPLs
Authors: Phil Trinder
Venue: Proceedings of the third international workshop on Database programming languages : bulk types persistent data: bulk types persistent data (1992)

This paper argues that comprehensions, a construct found in some programming languages, are a good query notation for DBPLs. It is shown that, like many other query notations, comprehensions can be smoothly integrated into DBPLs and allow queries to be expressed clearly, concisely and efficiently. More significantly, two advantages of comprehensions are demonstrated. The first advantage is that, unlike conventional notations, comprehension queries combine computational power with ease of optimisation. That is, not only can comprehension queries express both recursion and computation, but equivalent comprehension transformations exist for all of the major conventional optimisations. The second advantage is that comprehensions provide a uniform notation for expressing and performing some optimisation on queries over several bulk data types. The bulk types that comprehensions can be defined over include sets, relations, bags and lists. A DBPL can also be automatically extended to provide and partially optimise comprehension queries over new bulk types constructed by the application programmer, providing that the new type has some well-defined properties.
Spatial database access methods
Authors: Betty Salzberg, David B. Lomet
Venue: ACM SIGMOD Record (1991)

In the discussion of research issues in spatial databases (SIGMOD Record vol. 19, no. 4, Dec 1990) we stated the need for a robust framework for analytical comparison of a broad range of spatial access methods. The utility of such a comparison, even of very closely related access methods, was shown in [FALO87]. A necessary precondition for a meaningful analytical comparison is the existence of strong analytical results for individual access methods. In the following paper, Salzberg and Lomet take the worst case analytical results on fan-out and average storage utilization they obtained for their hB-tree [LOME89,LOME90] and extend the analysis to another robust method, Z-order encoding [OREN84]. We think this paper is a start on the comparative assessment of access methods based on analytical results. We hope to see future work extend the framework beyond worst case analysis, and to other access methods as well.
Wafer-Scale Transducer Arrays
Authors: Glenn H. Chapman, M. Parameswaran, Marek Syrzycki
Venue: Computer (1992)

The production of wafer-scale transducer arrays using laser interconnection techniques and micromatching technology is discussed. The design of a wafer-scale thermal dynamic scene simulator that was implemented using the laser-linking redundancy technique is presented to illustrate typical design requirements. The simulator uses small arrays of thermal pixels and control circuitry in 3 mu m CMOS technology.
Characterizing memory performance in vector multiprocessors
Authors: J. E. Smith, W. R. Taylor
Venue: Proceedings of the 6th international conference on Supercomputing (1992)

We propose a set of three memory performance measures directed at vector multiprocessors. One is the port reservation time which is closely related to the commonly-used memory bandwidth measure. The second is the vector fill time and is the latency through the memory system for an entire vector operation. The third is the slowest element time, which is the highest effective latency of all the elements of a vector. The three measures are sufficent to characterize the memory system's influence on the processor's usage of memory ports, functional units, and vector registers--the three main resources that determine vector performance. Simulation results for a next-generation-class vector multiprocessor are given to illustrate typical values for the measures and their inter-relationships. These results display a type of bimodal performance behavior where performance is better for both high and low vectorization levels than it is for moderate vectorization levels. The results are also used with a simple code sequence to illustrate the effect of memory system delays on chained and non-chained performance. These results suggest that chaining may be more efficient if longer vector lengths are used.
A simple reliable globally-ordered broadcast service
Authors: Dan Oestreicher
Venue: ACM SIGOPS Operating Systems Review (1991)

A practical basis for implementing fault tolerant applications is described. At the application programming level a set of group communication and transaction handling primitives is provided. A fault tolerant globally--ordered broadcast service provides the basis for those primitives.The design is based on Kaashoek amp; Tanenbaum's reliable broadcast [4], [5], but modified, and implemented on a standard Unix system using the industry--standard TCP/IP protocol family.The implementation of the broadcast service is simple, and could be implemented at a low level to provide a new type of reliable LAN, or it can be implemented by using spare cycles on server machines which are also performing other tasks. The implementation of the group primitives using the broadcast service is not so simple, and is indicated, but not described in detail.Code size and performance figures are given for an implementation of the system.