ppxscal/embedding_network huggingface dataset:
An Information-Theoretic Analysis of Relational Databases Part II: Information Structures of Database Schemas
Authors: Tony T. Lee
Venue: IEEE Transactions on Software Engineering (1987)

The structural properties of acyclic database schemas, especially the interrelationships between acyclic join dependencies and multivalued dependencies, are examined in this paper. The intersection closure of a database schema is a semilattice, which is usually represented by Hasse diagram in algebra. The Hasse diagram of a schema is analogous to the Bachman diagram of a network model. Based on the topological structures of Hasse diagrams, the acyclic join dependency is proved to be equivalent to a set of conflict-free multivalued dependencies. Furthermore, we show that if the Hasse diagram is loop free, then the corresponding set of multivalued dependencies is also contention-free. This result is consistent with previous results derived from the Bachman diagram.
Theory of Clocking for Maximum Execution Overlap of High-Speed Digital Systems
Authors: Nohbyung Park, Alice C. Parker
Venue: IEEE Transactions on Computers (1988)

The effect of clocking schemes on overlapped execution performance in a digital system is described and quantified. Effects of branching, data dependencies, and resource conflicts between consecutive tasks are considered. Some problems of clocking scheme synthesis for the design of digital systems with maximum execution overlap are examined. Effects of performance of the choice of clocking scheme, partitioning of functions into the time steps, the number of clock phases, the length of each phase (i.e., how to pipeline), and the assignment of functions to clock phases are treated.
A component part for a performance course
Authors: Charles M. Shub
Venue: ACM SIGCSE Bulletin (1986)

The maturation of Computer System Performance Courses is briefly described giving excerpts from the two major ACM curriculum documents and providing a list of possible texts for such a course. It is then proposed that a course in performance evaluation contain a component on the role of performance work in the product life cycle. A prototype model for this is described in detail. The description includes the need for such work, who accomplishes it, what sort of interactions are necessary and appropriate, and what steps comprise integrating performance work into a product life cycle.
On ordered languages and the optimization of linear functions by greedy algorithms
Authors: Ulrich Faigle
Venue: Journal of the ACM (JACM) (1985)

The optimization problem for linear functions on finite languages is studied, and an (almost) complete characterization of those functions for which a primal and a dual greedy algorithm work well with respect to a canonically associated linear programming problem is given. The discussion in this paper is within the framework of ordered languages, and the characterization uses the notion of rank feasibility of a weighting with respect to an ordered language. This yields a common generalization of a sufficient condition, obtained recently by Korte and Lov&aacute;sz for greedoids, and the greedy algorithm for ordered sets in Faigel's paper [6]. Ordered greedoids are considered the appropriate generalization of greedoids, and the connection is established between ordered languages, polygreedoids, and Coxeteroids. Answering a question of Bj&ouml;rner, the author shows in particular that a polygreedoid is a Coxeteroid if and only if it is derived from an integral polymatroid.
Publishing requires much more than desktop publishing systems
Authors: Michael B. Verderman
Venue: Proceedings of the 15th annual ACM SIGUCCS conference on User Services (1987)

What constitutes a good publication? A money-making organization might examine the amount of paid subscribers to find out. Certainly, regular reader feedback is a good indication, too. But in an academic environment, the basis for decisions must be different since the goal is not generally a money-making one, nor is the readership always vocal. During the summer of 1986, the University Computing publications staff at UH, undertook the major task of totally redesigning publications scheme. This overhaul was implemented in several phases: analysis of current methods from distribution to audience; analysis of methods desired&mdash;taking into consideration budget restraints and available equipment; correlation of this information into a presentation for the Vice President for Computing; and implementation of the final, approved plan. Certainly a factor involved with creating the initial momentum for our changes was the popularity of desktop publishing systems, which was readily available for University Computing publications department use. Other events also contributed to keeping the momentum going for the 'research and development' of new computing publications. These factors included an interest in increased visibility and publicity (this expressed by the vice president for computing), and publications staff was not pleased with the distribution and content of publications, and a desire to upgrade, centralize, and professionalize production. We opted to look at the big picture, not just to improve the aesthetics of the publications. The result was the culmination of many person-hours worth of work studying and refining the numerous ideas for new publications. The outcome was the elimination of one publication, the birth of a quarterly journal, a total revision of the computing newsletter, and extended support of online bulletins.
Esplex: A rule and conceptual model for representing statutes
Authors: C. Biagioli, P. Mariani, D. Tiscornia
Venue: Proceedings of the 1st international conference on Artificial intelligence and law (1987)

The characteristics of the ESPLEX system which may be defined as a &ldquo;rule and conceptual based model&rdquo; are illustrated, together with the possibilities for its utilization, its similarities with other existing projects, and the requisites of the knowledge representation language. The methodology and the theoretical propositions that have led to the definition of the representation language are therefore explained. The characteristics of the system which manages the knowledge base are also described and a brief comment is made regarding future development.
The RM-CELL: A set of old ideas that produce new results
Authors: G de la Pena Casares
Venue: Issue 97 (July 1986) (1986)

This paper reports a system with unexpected features. Starting from scratch, it learns to synthesize the function between the input and the output of a black box, which receives N bits and produces one. After being trained with one pass of a random sample of inputs and outputs, the system reproduces the sample completely but, if the sample size is greater than, or equal to some minimum (that depends on the black box function), the system will forecast correctly outside of the learned sample. The system has been tested with functions that range from easy to difficult and it has survived (up to now) all the tests. One of them is here reported.
Acceptance trees
Authors: M. Hennessy
Venue: Journal of the ACM (JACM) (1985)

A simple model, AT, for nondeterministic machines is presented which is based on certain types of trees. A set of operations, &Sgr;, is defined over AT and it is shown to be completely characterized by a set of inequations over &Sgr;. AT is used to define the denotational semantics of a language for defining nondeterministic machines. The significance of the model is demonstrated by showing that this semantics reflects an intuitive operational semantics of machines based on the idea that machines should only be differentiated if there is some experiment that differentiates between them.
A note on the Berry-Meekings style metric
Authors: Warren Harrison, Curtis R. Cook
Venue: Communications of the ACM (1986)

A modification of the Berry-Meekings "style metric"&mdash;applied to software from the corporate environment&mdash;finds little relationship between this style metric and error proneness.
Optimistic concurrency control for abstract data types
Authors: Maurice Herlihy
Venue: ACM SIGOPS Operating Systems Review (1987)

A concurrency control technique is optimistic if it allows transactions to execute without synchronization, relying on commit-time validation to ensure serializability. This paper describes several new optimistic concurrency control techniques for objects in distributed systems, proves their correctness and optimality properties, and characterizes the circumstances under which each is likely to be useful. These techniques have the following novel aspects. First, unlike many methods that classify operations only as reads or writes, these techniques systematically exploit type-specific properties of objects to validate more interleavings. Necessary and sufficient validation conditions are derived directly from an object's data type specification. Second, these techniques are modular: they can be applied selectively on a per-object (or even per-operation) basis in conjunction with standard pessimistic techniques such as two-phase locking, permitting optimistic methods to be introduced exactly where they will be most effective. Third, when integrated with quorum-consensus replication, these techniques circumvent certain trade-offs between concurrency and availability imposed by comparable pessimistic techniques. Finally, the accuracy and efficiency of validation are further enhanced by some technical improvements: distributed validation is performed as a side-effect of the commit protocol, and validation takes into account the results of operations, accepting certain interleavings that would have produced delays in comparable pessimistic schemes.
Distributed training: the MSU computer laboratory departmental trainer program
Authors: Bill Brown, Marilyn Everlingham
Venue: Proceedings of the 15th annual ACM SIGUCCS conference on User Services (1987)

With the advent of microcomputers, distributed computing is here to stay. With distributed computing comes distributed expertise; people must learn to run their own computing centers, no matter what the size of the computers. In trying to deal with increased demands for training in a limited-resource environment, we have taken the natural step of distributing the responsibility for the training. With appropriate training materials, a person who knows how to use a program can lead someone else through the process of learning. The training materials must be sufficiently detailed to include training on all major features of the software that people regularly use and include conceptual material that takes the place of lectures. The commitment to distributed training must be real. Sufficient staff must be devoted to developing training materials because the materials must continue to evolve with the software it teaches and new materials must be created to meet the demands for training on new software.
Expert system applications in customer service
Authors: Stephen Schon, Omar Keith Helferich
Venue: Proceedings of the conference on The 1987 ACM SIGBDP-SIGCPR Conference (1987)

The competitive edge of using expert system technology is beginning to have an impact on the marketplace. Described here are applications of expert system technology to customer service and many of the ideas presented here are applicable to other areas of business as well. This project was accomplished in cooperation with the Customer Service Department of a major U.S. chemical company, and this paper describes the design, implementation, and results of a diagnostic expert system prototype and the design of an Expert Inquiry Handler for customer service. The prototype design was based on a previously successful design by the authors, and the Expert Inquiry Handler design addresses what it means to do intelligent inquiry handling in customer service and how an Expert Inquiry Handler interfaces with its resources (data base and people) to accomplish its job.
Planning for software verification and validation
Authors: D R Wallace, R U Fujii
Venue: ACM SIGSOFT Software Engineering Notes (1987)

Software verification and validation (V amp;V) is a systems engineering process that supports the evaluation of software quality. Software V amp;V requires careful planning for effective application of a rigorous methodology for evaluating the correctness and quality of the software product throughout the software life cycle. A recent standard, the IEEE Std. 1012--1986, Standard for Software Verification and Validation Plans (SVVP), provides direction for preparing or assessing a software verification and validation plan.This Standard provides uniform and minimum requirements for the format and content of Software Verification and Validation Plans (SVVPs). The Standard specifies minimum verification and validation tasks and the associated inputs and outputs which must be included in SVVPs for noncritical software. it recommends their inclusion in SVVPs for noncritical software. The Standard lists optional V amp;V tasks to permit the V amp;V planner to tailor the V amp;V effort to suit project needs.Definitions for verification, validation, critical software, and software lifecycle are adapted from those from the IEEE Standard Glossary of Software Engineering Terminology, ANSI/IEEE Std 729-1983. The IEEE 1012 Standard directs that V amp;V shall be initiated early in the lifecycle and parailels development. The Standard can be used with a wide variety of lifecycle models and approaches, i.e., the traditional waterfall model as well as rapid prototyping. In order for the Standard to have broad use, it does not specify a particular V amp;V organizational approach; nor does it require specific tools or methodologies to perform the V amp;V tasks but rather establishes minimum criteria for a V amp;V plan.
Starting and supporting a software library
Authors: Les Lloyd
Venue: Proceedings of the 15th annual ACM SIGUCCS conference on User Services (1987)

Drew is a private, liberal arts institution located in Madison, New Jersey. Originally founded as a Methodist seminary in the mid-1800's, the College of Liberal Arts was founded in 1929. The College of Liberal Arts, Theological School and Graduate School comprise Drew University today with combined enrollments of about 2200 students. The College of Liberal Arts offers 27 degree programs. There are about 100 full-time faculty members, 1600 students and 300 staff and administration in the College. In 1983, the faculty of the College of Liberal Arts initiated and overwhelmingly voted to support the Computer Initiative. The effort gained national attention, as Drew became the nation's first major liberal arts college to issue computers to incoming freshmen as part of their regular education package. Through this initiative, beginning in fall 1984, every Drew freshman was issued a personal computer for the course of undergraduate studies and to keep upon graduation. At the same time, every faculty member was issued a personal computer, and faculty voluntarily embraced a massive and continuing education program themselves to be able to adapt the computer into the college curriculum. Staff offices also received computers as they were requested and faculty requests for additional computers to take home are considered on an individual basis. When a freshman arrives at Drew, his or her computer and printer is set-up in his room and ready for use. A crew of students supervised by a staff member installs each computer and tests it during the two weeks before classes begin in the fall. This period of time is necessary to work around the physical plant's painting and cleaning schedule and dorm use by summer programs. In addition to the hardware, freshmen have received one or two word processors, along with graphics, spreadsheets and database software. The Computer Initiative budget includes a line for software expense. The general guidelines on this fund is that the first copy of a package will be purchased by the Computer Initiative. If a department or course requires additional copies, we will do the price negotiation and acquisition of the software, but try to get them to fund it or charge the students depending on the use of the package. If the department's budget cannot handle the purchase, the Computer Initiative and/or the Dean of the College will assist in finding funds.
Why TCP timers don't work well
Authors: L Zhang
Venue: Proceedings of the ACM SIGCOMM conference on Communications architectures protocols (1986)

Repeated observation of TCP retransmission timer problems stimulated investigation into the roles and limitations of timers. Timers are indispensable tools in building up reliable distributed systems. However, as the experience with the TCP retransmission timer has shown, timers have intrinsic limitations in offering optimal performance. Any timeout based action is a guess based on incomplete information, and as such is bound to be non-optimal. We conclude that, if we aim at high performance, we should use external events as a first line of defense against failures, and depend on timers only in cases where external notification has failed.
Abstraction mechanisms in hypertext
Authors: Pankaj, K. Garg
Venue: Communications of the ACM (1988)

Abstraction is the means by which information can be stored and retrieved from an information structure at different levels of detail and from different perspectives. As such, abstraction mechanisms in hypertext are interesting to evaluate from a theoretical perspective as they become various first-order logic formulae.
Benchmark semantics
Authors: Carl G. Ponder
Venue: ACM SIGPLAN Notices (1988)

Be careful when interpreting benchmark measurements that compare two languages or two implementations of the same language. A program expressed in two different languages rarely computes the exact same function in both cases. The same goes for a program run on two different implementations of the same language. The implementation details ultimately affect the language semantics as well as the benchmark performance. Here are some simple examples of this effect.
Line drawings of octree-represented objects
Authors: Jack Veenstra, Narendra Ahuja
Venue: ACM Transactions on Graphics (TOG) (1988)

The octree structure represents the space occupied by an object as a juxtaposition of cubes, where the sizes and position coordinates of the cubes are integer powers of 2 and are defined by a recursive decomposition of three-dimensional space. This makes the octree structure highly sensitive to object location and orientation, and the three-dimensional shape of the represented object obscure. It is helpful to be able to see the actual object represented by an octree, especially for visual performance evaluation of octree algorithms. Presented in this paper is a display algorithm that helps visualize the three-dimensional space represented by the octree. Given an octree, the algorithm produces a line drawing of the objects represented by the octree, using parallel projection, from any specified viewpoint with hidden lines removed. The order in which the algorithm traverses the octree has the property that if node x occludes node y, then node x is visited before node y. The algorithm produces a set of long, straight visible edge segments corresponding to the visible surface of the polyhedral object represented by the octree. Examples of some line drawing produced by the algorithm are given. The complexity of the algorithm is also discussed.
A knowledge-based problem-specific program generator
Authors: T Hrycej
Venue: ACM SIGPLAN Notices (1987)

A commercially relevant paradigm for a knowledge-based problem-specific program generator is described. It is applicable to repeatedly implemented software, particularly in the intermediate area between the exclusive and standard software. Not the first implementation, but the repeated ones are supported using the "problem-specific programming knowledge" collected during the past implementations. The technical details, as knowledge representation and functional component, are explained and illustrated on an example. Finally, conditions for an efficient application of the program generator are defined. The system can be developed at a relatively low expense of several months.
A constraint approach to mastermind in logic programming
Authors: Pascal van Hentenryck
Venue: Issue 103 (Jan., 1988) (1988)

Logic programming is a convenient tool for stating combinatorial problems due to its nondeterminism and its relational form. It is not surprising that simple and declarative programs can be written for problems like mastermind. However, due to their search strategy, logic languages are also very inefficient for solving the natural formulation of problems. Moving away from this natural formulation leads to much programming effort and to less modifable and extensible programs. This paper shows, on the mastermind example, that it is possible to write very declarative programs which will be executed efficiently by an extended logic programming language. The key idea is to embed consistency techniques inside logic programming. Within this approach, constraints are used actively to prune the search space in an "a priori" way instead of the passive way (for testing values) of usual languages. The resulting program outperforms all the proposed algorithms and achieves a speed-up of 40 over Shapiro's program in the average and a speed-up of 72 on Powers' benchmark.
A taxonomy of Ada packages
Authors: Ken Sumate, Kjell Nielsen
Venue: ACM SIGAda Ada Letters (1988)

A taxonomy of Ada packages is presented to describe their use in designing large programs. The categories include application, communication, and helper packages. Helper packages are further subdivided into definitions, services, and data managers. Data managers are further divided into abstract data types and resources. An abstract data type can be of an open or a closed type. Each of the categories described as part of the taxonomy is illustrated with a coding example that shows both the package and how the package is used.
A model to order the encryption algorithms according to their quality
Authors: A. R. Prieto, J. G. Tomas
Venue: ACM SIGCOMM Computer Communication Review (1987)

Usually the unicity distance is used to give the strength of encryption algorithms. In this work, the behaviour of encipherment algorithm has been analyzed and two different parameters are proposed in order to evaluate the quality. These parameters are checked against the unicity distance and a final test has been executed, using DES.
A study of transitive closure as a recursion mechanism
Authors: H. V. Jagadish, Rakesh Agrawal, Linda Ness
Venue: ACM SIGMOD Record (1987)

We show that every linearly recursive query can be expressed as a transitive closure possibly preceded and followed by operations already available in relational algebra. This reduction is possible even if there are repeated variables in the recursive literals and if some of the arguments in the recursive literals are constants. Such an equivalence has significant theoretical and practical ramifications. One the one hand it influences the design of expressive notations to capture recursion as an augmentation of relational query languages. On the other hand implementation of deductive databases is impacted in that the design does not have to provide the generality that linear recursion would demand. It suffices to study the single problem of transitive closure and to provide an efficient implementation for it.
The automated tutoring of introductory computer programming
Authors: J. R Anderson, E. Skwarecki
Venue: Communications of the ACM (1986)

The methodologies of artificial intelligence and the knowledge of cognitive psychology can be used to automatically generate fine-grain tutorial interactions, rather than having to program them manually.