ppxscal/embedding_network huggingface dataset:
Federated database systems for managing distributed, heterogeneous, and autonomous databases
Authors: Amit P. Sheth, James A. Larson
Venue: ACM Computing Surveys (CSUR) (1990)

A federated database system (FDBS) is a collection of cooperating database systems that are autonomous and possibly heterogeneous. In this paper, we define a reference architecture for distributed database management systems from system and schema viewpoints and show how various FDBS architectures can be developed. We then define a methodology for developing one of the popular architectures of an FDBS. Finally, we discuss critical issues related to developing and operating an FDBS.
On the adequacy of program dependence graphs for representing programs
Authors: S. Horwitz, J. Prins, T. Reps
Venue: Proceedings of the 15th ACM SIGPLAN-SIGACT symposium on Principles of programming languages (1988)

Program dependence graphs were introduced by Kuck as an intermediate program representation well suited for performing optimizations, vectorization, and parallelization. There are also additional applications for them as an internal program representation in program development environments. In this paper we examine the issue of whether a program dependence graph is an adequate structure for representing a program's execution behavior. (This question has apparently never been addressed before in the literature). We answer the question in the affirmative by showing that if the program dependence graphs of two programs are isomorphic then the programs are strongly equivalent.
Performance Analysis of Multistage Interconnection Networks with Hierarchical Requesting Model
Authors: W.-T. Chen, J.-P. Sheu
Venue: IEEE Transactions on Computers (1988)

Analyzes the performance of the multistage interconnection networks (MINs) for interconnecting N processors or N processors to N commonly shared memory modules in a multiprocessor system. A general model, called hierarchical requesting model, has been proposed. The performance of the MINs with respect to their memory bandwidth is analyzed and is compared to that of a crossbar under the proposed model. Based on the analytical results, the authors present a task allocation strategy to increase the memory bandwidth of the MINs.
Overlapped loop support in the Cydra 5
Authors: James C. Dehnert, Peter Y.-T. Hsu, Joseph P. Bratt
Venue: ACM SIGARCH Computer Architecture News (1989)

The CydraTM 5 architecture adds unique support for overlapping successive iterations of a loop to a very long instruction word (VLIW) base. This architecture allows highly parallel loop execution for a much larger class of loops than can be vectorized, without requiring the unrolling of loops usually used by compilers for VLIW machines. This paper discusses the Cydra 5 loop scheduling model, the special architectural features which support it, and the loop compilation techniques used to take full advantage of the architecture.
Multiversion Cautious Schedulers for Database Concurrency Control
Authors: T. Ibaraki, Tiko Kameda, Naoki Katoh
Venue: IEEE Transactions on Software Engineering (1990)

Let MC stand for a class of logs (i.e. sequences of read/write steps of transactions) that are serializable when multiple versions of the data items are maintained. The multiversion cautious scheduler, MCS(MC) which is introduced, outputs a sequence belonging to MC by reordering, if necessary, the incoming sequence of requests from transactions and it never resorts to rollbacks. In the model, transactions on arrival predeclare their read sets and write sets. It is shown that MCS(MWW) and MCS(MWRW) can be executed in polynomial time, where MWW and MWRW are multiversion classes of logs serializable under the write-write and write-read-write constraints respectively. For any multiversion class MC of interest, MCS(MC) does not exhibit cancellation anomaly, i.e. it functions correctly even if some of the predeclared steps are canceled. Furthermore, MCS(MWW) functions correctly, even if transactions issue more read operations than they predeclared. Thus, MCS(MWW) allows each transaction to predeclare only its write set.
Success with the project-intensive model for an undergraduate software engineering course
Authors: Linda M. Northrop
Venue: ACM SIGCSE Bulletin (1989)

There is a tremendously increasing need for software in all areas of society (the software crisis) and hence a need for increased numbers of software engineers as well as increased productivity of the current software engineers [1]. Improving the productivity of software engineers necessitates new ways of viewing software, better procedures for creating it, and most importantly, better education of current and prospective software engineers regarding the development process [2]. Software engineering is thus rapidly being incorporated into undergraduate and graduate computer science curricula and is emerging as a separate discipline. In particular, the senior level project course has received much attention as a way to provide a software engineering experience at the undergraduate level. Project teams in such courses usually consist of two to four students. This paper describes a project-intensive software engineering course in which twenty-three students worked effectively as a single project team.
On the reduction of linear systems of difference equations
Authors: M. A. Barkatou
Venue: Proceedings of the ACM-SIGSAM 1989 international symposium on Symbolic and algebraic computation (1989)

This paper deals with linear systems of difference equations whose coefficients admit generalized factorial series representations at z = &infin;. We shall give a criterion by which a given system is determined to have a regular singularity. In the same manner, we give an algorithm, implementable in a computer algebra system, which reduces in a finite number of steps the system of difference equations on an irreducible form.
A New Approach to Realizing Partially Symmetric Functions
Authors: J. Ja'Ja', S.-M. Wu
Venue: IEEE Transactions on Computers (1989)

Consideration is given to the class of partially symmetric functions and a method for realizing them is outlined. Each such function can be expressed as a sum of totally symmetric functions such that a circuit can be designed with its complexity dependent on the size of such symmetric cover. The authors compare the sizes of symmetric and sum-of-product covers and show that the symmetric cover will be substantially smaller for this class of functions.
Iterative scaling of marks using APL-a case study
Authors: P. Petocz
Venue: ACM SIGAPL APL Quote Quad (1987)

This paper presents a case study where APL was used successfully to tackle a problem that appeared to be quite complex. The work was carried out for the NSW Department of Technical and Further Education in 1985 and 1986, and is the subject of ongoing research at present. A common problem in educational measurement is the comparison of scores obtained on different tests when the candidature for each test is not identical. Such a situation exists in NSW at the Higher School Certificate secondary school matriculation examinations. Different subjects attract candidatures of differing ability, yet it is important to calculate an aggregate mark as fairly as possible since it is used as a basis for selection into tertiary institutions. The iterative scaling procedure which has been used has been the subject of some controversy, caused in part by the fact that most people find it hard to understand exactly what is going on. The Tertiary Preparation Certificate is a matriculation course offered by the NSW Department of TAFE and is designed to prepare mature-age students for tertiary study. The aggregate mark obtained in this course was required to be comparable to HSC aggregate marks, so the iterative scaling procedure was implemented using APL to process these marks. The APL program has been used successfully during the previous two years on groups of up to 100 students. The algorithm is documented here for the first time in a form that is ready to be used by anyone with access to APL. There is discussion on the rationale and assumptions used in the calculations, and comments are made on the role that APL played in the whole process.
A programming model for the Mark III hypercube with multiple processor nodes
Authors: B. A. Zimmermann, G. A. Crichton
Venue: Proceedings of the third conference on Hypercube concurrent computers and applications: Architecture, software, computer systems, and general issues - Volume 1 (1988)

The Caltech/JPL Mark III Hypercube originally consisted of an ensemble of processing elements each containing two Motorola M68020 processors &mdash; one M68020 processor and a M68881 Floating-Point coprocessor used for data processing, the other M68020 processor dedicated to hypercube communications. In the interest of achieving even greater computational capability a third processing element, the Weitek XL system, was added to enhance floating point performance. Each of what is now three processing elements is configured with CPU, local static memory, communication peripherals, clocks, and control logic. In addition, they share 4 megabytes of dynamic memory on the node card. We will describe a programming model and environment that accommodates the operation of the three processors, preparation, extended Crystalline communications, and intranode concurrency.
Implementing Remote Evaluation
Authors: James W. Stamos, David K. Gifford
Venue: IEEE Transactions on Software Engineering (1990)

Remote evaluation (REV) is a construct for building distributed systems that involves sending executable code from one computer to another computer via a communication network. How REV can reduce communication and improve performance for certain classes of distributed applications is explained. Implementation issues are discussed. REV is incorporated into a high-level programming language by defining its syntax and its semantics. The compile-time and run-time support for REV is discussed in both heterogeneous and homogeneous systems and compared to that needed by a remote procedure call implementation. Sample performance measurements are included. Experience with a prototype REV implementation is summarized.
Structured content modeling for cinematic information
Authors: B. Rubin, G. Davenport
Venue: ACM SIGCHI Bulletin (1989)

For cinematic material to become useful as an online information resource, a structured content model must be developed. This model should enable both a viewer and an automated retrieval/presentation system to navigate and manipulate picture and sound information. Here we present the functional requirements for such a model, and then discuss a video editing and viewing environment, currently under development at the MIT Media Laboratory, which utilizes content information.
Software development productivity tools and metrics
Authors: A. S. Duncan
Venue: Proceedings of the 10th international conference on Software engineering (1988)

The continuing emphasis on improving productivity in the building of software has resulted in clearer definitions of software quality and software engineer productivity, and a greater interest by management and software engineer alike in the tools and measurements that aid in knowing a project is &ldquo;in control&rdquo;. This paper describes the software development process used within one software engineering group at Digital Equipment Corporation, and the methods and tools used within the group to support the development of software products. Experience in the application of software metrics to parts of the process as a means of quantifying productivity and quality is described.
Smalltalk scaffolding: a case study of minimalist instruction
Authors: Mary Beth Rosson, John M. Carrol, Rachel K. E. Bellamy
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: Empowering people (1990)

A curriculum was developed to introduce users to the Smalltalk object-oriented programming language. Applying the Minimalist model of instruction [3], we developed a set of example-based learning scenarios aimed at supporting real work, getting started fast, reasoning and improvising, coordinating system and text, supporting error recognition and recovery, and exploiting prior knowledge. We describe our initial curriculum design as well as the significant changes that have taken place as we have observed it in use.
Autonomous Robotic Vehicle Road Following
Authors: D. Kuan, G. Phipps, A.-C. Hsueh
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1988)

A description is given of the system architecture of an autonomous vehicle and its real-time adaptive vision system for road-following. The vehicle is a 10-ton armored personnel carrier modified for robotic control. A color transformation that best discriminates road and nonroad regions is derived from labeled data samples. A maximum-likelihood pixel classification technique is then used to classify pixels in the transformed color image. The vision system adapts itself to road changes in two ways; color transformation parameters are updated infrequently to accommodate significant road color changes, and classifier parameters are updated every processing cycle to deal with gradual color and intensity changes. To reduce unnecessary computation, only the most likely road region in the segmented image is selected, and a polygonal representation of the detected road region boundary is transformed from the image coordinate system to the local vehicle coordinate system based on a flat-earth assumption.
Optimal Search Policies for Searches with I/O Bound Tasks
Authors: Harold S. Stone
Venue: IEEE Transactions on Computers (1989)

Two models are presented for conducting simple searches under the assumption that the tasks within the search tree are complex and may be I/O bound. The objective is to achieve the minimum expected time to completion. The simpler model assumes that the search paths are disjoint. The optimal policy in the general case is to run the tasks with the highest ratio of success probability per cycle expended. If one task is sufficiently small compared to the other task that it completes first in all schedules, the optimum scheduling policy is based on a comparison of ratios of the form p/r, where p is the probability of success and r is the marginal processing rate of a task. For the second model the search paths are independent, and the success or failure on one path is not related to the success or failure on any other path. This model generally gives priority to the task that has the highest probability per marginal execution rate. For both models, the results reported hold only for a search with two paths. For the problem of scheduling N tasks the policy of giving priority to tasks according to descending values of probability of success over cost is generally a good idea, although it does not necessarily yield an optimum schedule.
Complexity of deciding Tarski algebra
Authors: D. Yu Grigor'ev
Venue: Journal of Symbolic Computation (1988)

Let a formula of Tarski algebra contain k atomic subformulas of the kind (f"i >= 0), 1 =
Automated disaster plan auditing using knowledge base technology
Authors: Jonathan Simon, Aaron Konstam
Venue: ACM SIGUCCS Newsletter (1988)

Management Information System (MIS) disaster and contingency planning are the principal ingredients for the success of a computer center's reorganization pending a system loss but there is is very little information published addressing the details of how to be assured of a proper backup and recovery strategy. Disaster planning is a phrase we are using to describe the act of preparing for a disaster, such as backup procedures, insurance acquisition, fire protection and maintenance of a contingency plan. The contingency plan, on the other hand, explicitly covers the recovery procedures, responsibilities, and supplementary disaster planning, that should take place once a disaster occurs. It should be clear that there is a cyclical relationship between these two tightly related planning functions. For that reason we will use the term disaster plan to refer to both disaster and contingency planning.
Limits on the provable consequences of one-way permutations
Authors: R. Impagliazzo, S. Rudich
Venue: Proceedings of the twenty-first annual ACM symposium on Theory of computing (1989)

We present strong evidence that the implication, &ldquo;if one-way permutations exist, then secure secret key agreement is possible&rdquo;, is not provable by standard techniques. Since both sides of this implication are widely believed true in real life, to show that the implication is false requires a new model. We consider a world where all parties have access to a black box for a randomly selected permutation. Being totally random, this permutation will be strongly one-way in a provable, information-theoretic way. We show that, if P = N P, no protocol for secret key agreement is secure in such a setting. Thus, to prove that a secret key agreement protocol which uses a one-way permutation as a black box is secure is as hard as proving P &ne; N P. We also obtain, as a corollary, that there is an oracle relative to which the implication is false, i.e., there is a one-way permutation, yet secret-exchange is impossible. Thus, no technique which relativizes can prove that secret exchange can be based on any one-way permutation. Our results present a general framework for proving statements of the form, &ldquo;Cryptographic application X is not likely possible based solely on complexity assumption Y.&rdquo;
Modified-Mesh Connected Parallel Computers
Authors: D. A. Carlson
Venue: IEEE Transactions on Computers (1988)

The author explores modifications of a mesh-connected parallel computer for the purpose of increasing the efficiency of executing important application programs. These modifications are made by adding one or more global mesh structures to the processing array. The author shows how his modifications allow asymptotic improvements in the efficiency of executing computations having low to medium interprocessor communication requirements (e.g. tree computations, prefix computations, or finding the connected components of a graph). For computations with high interprocessor communication requirements such as sorting, the author shows that they offer no speedup. He also compares the modified mesh-connected parallel computer to other similar organization including the pyramid, the X-tree, and the mesh-of-trees.
Correction of phonographic errors in natural language interfaces
Authors: J. Veronis
Venue: Proceedings of the 11th annual international ACM SIGIR conference on Research and development in information retrieval (1988)

In this paper, we point out that, in applications available to the general public, and/or natural language interfaces, the correction of phonographic errors (which are competence errors) is far more important than the correction of typographical errors (which are simply performance errors). Many studies aimed at the correction of typographical errors have been carried out, but relatively few tackle the problem of phonographic correction, and they are generally based on more or less ad hoc methods. We propose a mathematical framework for phonographic correction by defining a similarity relation between phonetically related substrings and a dissimilarity index between strings. We also provide a simple and efficient algorithm for recognizing words in dictionaries from misspelt inputs including both typographical and phonographic errors.
A structured approach to analysis and design of complex systems
Authors: F. Evans, J. Jantzen
Venue: ACM SIGAPL APL Quote Quad (1990)

An automatic control system for managing the heating of a modern building may involve several thousands of components and feedback loops. As such systems grow, decomposition into (nested) subsystems becomes increasingly necessary. The subject of the poster session is complexity in large scale systems. We think we can make the computer manage the complexity in any system that can be described in a block-diagram. A variety of complex systems are represented by different types of block-diagrams. They have one theoretical concept in common: connectedness. Directed graphs (digraphs) can describe the fundamental concepts of structure and reachability, and graph theory provides a consistent mathematical theory of it. The South Bank Polytechnic and the Technical University of Denmark are actively concerned through industrial collaborators with problems of energy management for modern buildings control of waste water in urban sewage networks fuzzy control of industrial processes engineering management systems expert system design for fault diagnosis and food poisoning diagnosis. All these problems require a tool for i) inputting and editing of graphs, and ii) an executable, array based model. In the late 70'ies Franksen, Falster Evans (1979) proposed a description of control systems based on a Boolean array representation of digraphs. At APL87 Fordyce Sullivan presented an inference mechanism for VLSI chip manufacturing, also based on Boolean array structures (Fordyce Sullivan, 1987). The APL89 conference had a similar nested array approach (Jantzen, 1989), and recently, the beginning of a whole theory, based on the 'digraph approach' has been published (Reinschke, 1988). The poster session will present a digraph model, in which the nodes contain tree-structured, nested data. The oriented arcs display the flow of information. Internally each level of the diagram will be stored in a nested array. The user can draw the diagram directly on screen using a digitizer. The session will include live demonstrations of fault diagnosis on a water tank model of a sewage network a structured approach to expert system design interactive graphics for object oriented visual programming (APL2) frame based data systems (APL2). The demonstrations will emphasize the PC, PS/2 and RT/PC based aids to complexity management. The digraph approach promises speed and space gains due to the purely Boolean array representations, as well as user-friendliness due to automatic decomposition techniques.
Parallel algorithms for hermite normal form of an integer matrix
Authors: F. Siebert-Roch
Venue: Proceedings of the ACM-SIGSAM 1989 international symposium on Symbolic and algebraic computation (1989)

The main problem in the integral matrices triangularization is the 'intermediate coefficients swell'. This aspect limits the dimension of treated matrices. Since 1985, we have at our disposal, the lliopoulos algorithm to compute the Hermite Normal Form of an Integer Matrix controlling the coefficients growth by mean of the determinant. We present here two parallelizations of this algorithm and their implementations on a MIMD machine, with 16 processors.
A sound and complete query evaluation algorithm for relational databases with null values
Authors: Li Yan Yuan, Ding-An Chiang
Venue: ACM SIGMOD Record (1988)

Reiter has proposed extended relational theory to formulate relational databases with null values and presented a query evaluation algorithm for such databases. However, due to indefinite information brought in by null values, Reiter's algorithm is sound but not complete. In this paper, we first propose an extended relation to represent indefinite information in relational databases. Then, we define an extended relational algebra for extended relations. Based on Reiter's extended relational theory, and our extended relations and the extended relational algebra, we present a sound and complete query evaluation algorithm for relational databases with null values