ppxscal/embedding_network huggingface dataset:
Temporal database system implementations
Authors: Michael H. Böhlen
Venue: ACM SIGMOD Record (1995)

Although research on temporal database systems has been active for about 20 years, implementations have not appeared until recently. This is one reason why current commercial database systems provide only limited temporal functionality. This paper summarizes extant state of the art of temporal database implementations. Rather than being very specific about each system we have attempted to provide an indication of the functionality together with pointers to additional information. It is hoped that this leads to more efforts pushing the implementation of temporal database systems in the near future.
Enterprise Objects Framework: a second generation object-relational enabler
Authors: Charly Kleissner
Venue: Proceedings of the 1995 ACM SIGMOD international conference on Management of data (1995)

Today's information system executives desperately need to improve programmer productivity and reduce software maintenance costs. They are demanding flexibility in frameworks and architectures in order to meet unforeseen changes (see [Yankee 94]). Adaptability is a major requirement of most company's information systems efforts. Management of change is one of the key computing concepts of the 1990s.Object-oriented tools and development frameworks are starting to deliver the benefits of increased productivity and flexibility. These next-generation products now need to be combined with relational databases to leverage investments and facilitate access to business data. Object-Relational Enablers automate the process of storing complex objects in a relational database management system (see [Aberdeen 94]).The Enterprise Objects Framework product is a second generation product bringing the benefits of object-oriented programming to relational database application development. Enterprise Objects Framework enables developers to construct reusable business objects that combine business logic with persistent storage in industry-standard relational databases. Enterprise objects are first class citizens in the NEXTSTEP and OpenStep developer and user environments. They can be geographically distributed throughout heterogeneous servers within an enterprise using the Portable Distributed Objects product (see [NeXT-DO 94]).In this extended abstract we first describe the enterprise object distribution model and then give a brief synopsis of how relational data is mapped into objects. We then present an outline of the system architecture, explain how objects are mapped to multiple tables, and summarize the transaction semantics as well as the application development life-cycle. We conclude with an outlook on future development.
Generating sparse partial inductance matrices with guaranteed stability
Authors: Byron Krauter, Lawrence T. Pileggi
Venue: Proceedings of the 1995 IEEE/ACM international conference on Computer-aided design (1995)

This paper proposes a definition of magnetic vector potential that can be used to evaluate sparse partial inductance matrices. Unlike the commonly applied procedure of discarding the smallest matrix terms, the proposed approach maintains accuracy at middle and high frequencies and is guaranteed to be positive definite for any degree of sparsity (thereby producing stable circuit solutions). While the proposed technique is strictly based upon potential theory (i.e. the invariance of potential differences on the zero potential reference choice), the technique is, nevertheless, presented and discussed in both circuit and magnetic terms. The conventional and the proposed sparse formulation techniques are contrasted in terms of eigenvalues and circuit simulation results on practical examples.
Trading packet headers for packet processing
Authors: Girish P. Chandranmenon, George Varghese
Venue: ACM SIGCOMM Computer Communication Review (1995)

In high speed networks, packet processing is relatively expensive while bandwidth is cheap. Thus it pays to add information to packet headers to make packet processing easier. While this is an old idea, we describe several specific new mechanisms based on this principle. We describe a new technique, source hashing, which can provide O(1) lookup costs at the Data Link, Routing, and Transport layers. Source hashing is especially powerful when combined with the old idea of a flow ID; the flow identifier allows packet processing information to be cached, and source hashing allows efficient cache lookups. Unlike Virtual Circuit Identifiers (VCIs), source hashing does not require a round trip delay for set up. In an experiment with the BSD Packet Filter implementation, we found that adding a flow ID and a source hash improved packet processing costs by a factor of 7. We also found a 45% improvement when we conducted a similar experiment with IP packet forwarding. We also describe two other new techniques: threaded indices, which allows fast VCI-like lookups for datagram protocols like IP; and a Data Manipulation Layer, which compiles out all the information needed for Integrated Layer Processing into an easily accessible portion of each packet.
On the cost of monitoring and reorganization of object bases for clustering
Authors: Carsten A. Gerlhof, Alfons Kemper, Guido Moerkotte
Venue: ACM SIGMOD Record (1996)

Clustering is one of the most effective means to enhance the performance of object base applications. Consequently, many proposals exist for algorithms computing good object placements depending on the application profile. However, in an effective object base reorganization tool the clustering algorithm is only one constituent. In this paper, we report on our object base reorganization tool that covers all stages of reorganizing the objects: the application profile is determined by a monitoring tool, the object placement is computed from the monitored access statistics utilizing a variety of clustering algorithms and, finally, the reorganization tool restructures the object base accordingly. The costs as well as the effectiveness of these tools is quantitatively evaluated on the basis of the OO1-benchmark.
Testing of uncustomized segmented channel field programmable gate arrays
Authors: Tong Liu, Wei Kang Huang, Fabrizio Lombardi
Venue: Proceedings of the 1995 ACM third international symposium on Field-programmable gate arrays (1995)

This paper presents a methodology for production-time testing of (uncustomized) segmented channel field programmable gate arrays (FPGAs) such as those manufactured by Actel. The principles of this methodology are based on configuring the uncommitted modules (made of sequential and combinational logic circuits) of the FPGA as a set of disjoint one-dimensional arrays similar to iterative logic arrays (ILAs). These arrays can then be tested by establishing appropriate conditions such as constant testability (C-testability). A design approach is proposed. This approach is based on adding a small circuitry (consisting of two transistors) between each pair of uncustomized modules in a row for establishing the ILA configuration as a one-dimensional unilateral array. It also requires the addition of a further primary pin. Features such as number of test vectors and hardware requirements (measured by the number of additional transistors and primary input/output pins) are analyzed; it is shown that the proposed design approach requires a considerably smaller number of test vectors (a reduction of more than two orders of magnitude) and hardware overhead for the testing circuitry (a reduction of 13.6%) than the original FPGA configuration of [1]. The proposed approach requires 8+2nf vectors for testing the uncommitted FPGA of [1], where nf is the number of flip-flops (equal to the number of sequential modules for the FPGA of [1]) in a row of the FPGA.
Using medical objects: their structure, transmission, storage and usage
Authors: Frank M. Groom
Venue: ACM SIGBIO Newsletter (1995)

The medical community has traditionally utilized a common set of materials for diagnosis, documentation, and communicating about patients. These materials tend to be independently created, separately analyzed, but are used by medical personnel as an integrated set to deal with a particular patient. Included in such materials are patient history, problem symptoms, diagnostic imaging (X-Rays, MRI, PET, bone scans), patient logs, hospital specialist analysis, and consulting physician conclusions, treatments and results. Further records, such as hospital equipment used, drugs and materials used, facilities and personnel used, are all elements to be itemized and bills, insurance records, and forms are required for payment. Each of these medical elements can be created and captured as a separate object instance which can then be arrayed in a hierarchy in direct association with a particular patient.The advantage of employing objects to represent, display, store and transmit medical information is that objects encapsulate into a single entity all the elements required to use this medical information. An object contains the required data whether it be a document or an image. The object also contains information about the document such as who created it, who is authorized to use it, how big it is, and what special formats or data types are used. The most powerful thing about an object is that the program or method which operates against the data or document is encapsulated within the object along with the data to be processed. Therefore one need not acquire and run a special program to process the object since the required program is enclosed in the object. Finally, a messaging program is enclosed in the object as well to send messages to other objects if their assistance is required. Thus an object is a self contained entity. A physician, researcher, technician, or nurse can retrieve an object and merely execute it. One need not load a program, then download data, and finally run the program against the data. The data and the program are encapsulated as a unit and executed as a unit. One retrieves the object and executes it. For further references on objects, there is Grady Booch's Object-Oriented Analysis and Design, Benjamin Cummings, 1994, and Won Kim's Introduction to Object Oriented Databases, MIT Press, 1990.
SimKit: a high performance logical process simulation class library in C++
Authors: Fabian Gomes, John Cleary, Alan Covington, Steve Franks, Brian Unger, Zhong-e Ziao
Venue: Proceedings of the 27th conference on Winter simulation (1995)

SimKit is a C++ class library that is designed for fast discrete event simulation. SimKit presents a simple, elegant logical process view of simulation enabling both sequential and parallel execution without code changes to application models. The sequential executive performs well on a variety of UNIX platforms and facilitates debugging and testing. The parallel executive (WarpKit) is based on the Time Warp paradigm and supports efficient parallel execution on shared memory multiprocessor hardware such as the Silicon Graphics Power Challenge and the Sun SparcServer 1000/2000. This paper describes the design features of the SimKit system. A brief overview of the logical process modeling view commonly used in parallel discrete event simulation (PDES) is presented. The SimKit classes are then introduced followed by a brief tutorial on how to build and simulate object oriented models using SimKit.
Combinatorial S>n-Modules as Codes
Authors: Robert A. Liebler, Karl-Heinz Zimmermann
Venue: Journal of Algebraic Combinatorics: An International Journal (1995)

Certain \Bbb {Z}S_n-modules related to the kernels of incidence maps between types in the poset defined by the natural product order on the set of n-tuples with entries from &lcub;1, &hellip; ,m&rcub; are studied as linear codes (when coefficients are extended to an arbitrary field K). Their dimensions and minimal weights are computed. The Specht modules are extremal among these submodules. The minimum weight codewords of the Specht module are shown to be scalar multiples of polytabloids. A generalization of t-design arising from the natural permutation Sn-modules labelled by partitions with m parts is introduced. A connection with Reed-Muller codes is noted and a characteristic free formulation is presented.
Computing the discrepancy with applications to supersampling patterns
Authors: David P. Dobkin, David Eppstein, Don P. Mitchell
Venue: ACM Transactions on Graphics (TOG) (1996)

Patterns used for supersampling in graphics have been analyzed from statistical and signal-processing viewpoints. We present an analysis based on a type of isotropic discrepancy&mdash;how good patterns are at estimating the area in a region of defined type. We present algorithms for computing discrepancy relative to regions that are defined by rectangles, halfplanes, and higher-dimensional figures. Experimental evidence shows that popular supersampling patterns have discrepancies with better asymptotic behavior than random sampling, which is not inconsistent with theoretical bounds on discrepancy.
Visual designer's notes: CHI '95
Authors: Peter Vanags
Venue: ACM SIGCHI Bulletin (1995)

This article reports one visual designer's impressions of the CHI '95 conference, held in Denver, Colorado, from May 7 to 11, 1995. For the readers of this column who are regular conference attendees, I hope to provide glimpses of elements you may have missed. After all, with the frenetic schedule of a CHI conference, what attendee can actually see all they really want to see? And for those of you who were unable to attend this year, especially practitioners in the visual design community who were too busy designing interfaces to attend, I hope to give you a feeling for some of the big themes of this year's CHI, both within and outside the conference program, and to point you toward some of the interesting things you missed.For all readers, this article provides some useful pointers to the CHI '95 Conference Proceedings and the CHI '95 Conference Companion, for details about the notable papers and other presentations included in the conference program. This year's Electronic Proceedings and Companion CD-ROM is particularly complete, containing all the text of the weighty books, as well as accompanying graphics and illustrations, in a format that can be read by any HTML browser on any computer platform.This trip report focuses mostly on visual design related activities at the conference, and as a result isn't a very balanced or comprehensive report of what happened. Rather, this article presents my own selected thoughts and impressions as a sixth-time attendee of the conference and a practicing visual designer in the field of human-computer interaction. I hardly need to add that opinions presented in this article are my own, and do not always jibe with those of my employer, U dot I, Inc.
Overlapping batch quantiles
Authors: Demet C. Wood, Bruce W. Schmeiser
Venue: Proceedings of the 27th conference on Winter simulation (1995)

We show that although overlapping batch quantiles (OBQ) is asymptotically very similar to overlapping batch means, its performance for finite sample sizes is not. We show that the bias, the variance and the mean-squared-error of OBQ are not smooth functions of the batch size but rather cyclic. The cyclic behavior of OBQ depends on the marginal distribution, the point estimator of quantiles and the autocorrelation function and it diminishes with the sample size. We conclude that very large sample sizes and batch sizes are needed to obtain reliable standard error estimators when using OBQ, even for independently and identically distributed data.
Estimating understandability of software documents
Authors: Kari Laitinen
Venue: ACM SIGSOFT Software Engineering Notes (1996)

Software developers and maintainers need to read and understand source programs and other kinds of software documents in their work. Understandability of software documents is thus important. This paper introduces a method for estimating the understandability of software documents. The method is based on a language theory according to which every software document is considered to contain a language of its own, which is a set of symbols. The understandability of documents written according to different documentation practices can be compared using the rules of the language theory. The method and the language theory are presented by using source programs with different naming styles as example documents. The method can, at least theoretically, be applied to any kind of document. It can also be used to explain the benefits of some well-known software design methods.
An HPF compiler for the IBM SP2
Authors: Manish Gupta, Sam Midkiff, Edith Schonberg, Ven Seshadri, David Shields, Ko-Yang Wang, Wai-Mee Ching, Ton Ngo
Venue: Proceedings of the 1995 ACM/IEEE conference on Supercomputing (CDROM) (1995)

We describe pHPF, an research prototype HPF compiler for the IBM SP series parallel machines. The compiler accepts as input Fortran 90 and Fortran 77 programs, augmented with HPF directives; sequential loops are automatically parallelized. The compiler supports symbolic analysis of expressions. This allows parameters such as the number of processors to be unknown at compile-time without significantly affecting performance. Communication schedules and computation guards are generated in a parameterized form at compile-time. Several novel optimizations and improved versions of well-known optimizations have been implemented in pHPF to exploit parallelism and reduce communication costs. These optimizations include elimination of redundant communication using data-availability analysis; using collective communication; new techniques for mapping scalar variables; coarse-grain wavefronting; and communication reduction in multi-dimensional shift communications. We present experimental results for some well-known benchmark routines. The results show the effectiveness of the compiler in generating efficient code for HPF programs.
A static approach for compiling communications in parallel scientific programs
Authors: Damien Gautier de Lahaut, Cécile Germain
Venue: Scientific Programming (1995)

On most massively parallel architectures, the actual communication performance remains much less than the hardware capabilities. The main reason for this difference lies in the dynamic routing, because the software mechanisms for managing the routing represent a large overhead. This article presents experimental studies on benchmark programs concerning scientific computing; the results show that most communication patterns in application programs are predictable at compile-time. An execution model is proposed that utilizes this knowledge such that predictable communications are directly compiled and dynamic communications are emulated by scheduling an appropriate set of compiled communications. The performance of the model is evaluated, showing that performance is better in static cases and gracefully degrades with the growing complexity and dynamic aspect of the communication patterns.
A qualitative simulation approach for fuzzy dynamical models
Authors: Andrea Bonarini
Venue: ACM Transactions on Modeling and Computer Simulation (TOMACS) (1994)

This article deals with simulation of approximate models of dynamic systems. We propose an approach that is appropriate when the uncertainty intrinsic in some models cannot be reduced by traditional identification techniques, due to the impossibility of gathering experimental data about the system itself. The article presents a methodology for qualitative modeling and simulation of approximately known systems. The proposed solution is based on the Fuzzy Sets theory, extending the power of traditional numerical-logical methods. We have implemented a fuzzy simulator that integrates a fuzzy, qualitative approach and traditional, quantitative methods.
Development and implementation of measures of effectiveness for the universal joint task list in the joint theater level simulation
Authors: Ray Combs, Sam Parry, Chris Towery
Venue: Proceedings of the 27th conference on Winter simulation (1995)

This paper presents a methodology for evaluating tasks performed by a joint staff, as set forth in the Universal Joint Task List (UJTL). Measures of effectiveness are defined for selected sustainment and intelligence tasks. Results of experimental runs of the Joint Theater Level Simulation are presented to demonstrate the analysis process. Emphasis is placed on providing the staff planner with an ability to associate causal reasons for significant events in the exercise.
The Complexity of the Hajos Calculus
Authors: Toniann Pitassi, Alasdair Urquhart
Venue: SIAM Journal on Discrete Mathematics (1995)

The Hajos calculus is a simple, nondeterministic procedure that generates the class of non-3-colorable graphs. Mansfield and Welsch posed the question of whether there exist graphs that require exponential-sized Hajos constructions. Unless ${\rm NP} \neq {\rm coNP}$, there must exist graphs that require exponential-sized constructions, but to date, little progress has been made on this question, despite considerable effort. In this paper, we prove that the Hajos calculus generates polynomial-sized constructions for all non-3-colorable graphs if and only if extended Frege systems are polynomially bounded. Extended Frege systems are a very powerful family of proof systems for proving tautologies, and proving superpolynomial lower bounds for these systems is a long-standing, important problem in logic and complexity theory. We also establish a relationship between a complete subsystem of the Hajos calculus and bounded-depth Frege systems; this enables us to prove exponential lower bounds on this subsystem of the Hajos calculus.
Optimal Time Step Control for the Numerical Solution of Ordinary Differential Equations
Authors: Masaki Utumi, Ryuji Takaki, Toshio Kawai
Venue: SIAM Journal on Numerical Analysis (1996)

In solving differential equations using a finite stepsize $h$, an error $Eh^{p+1}$ is generated at each step and propagates. This phenomenon is treated as a dynamical process, where $h(t)$ is controlled to optimize a properly defined performance index. Applying the variational principle, optimal stepsize is found to be proportional to $(E\psi)^{-\frac{1}{p+1}}$, where $E$ is the error generation coefficient and $\psi$ is the adjoint function of the error variable. This means that conventional adaptive control strategies depending on local information $(E)$ only are not optimal in general, except for two special cases. The theory is applied to three test problems for two figures of merit. The method is compared with several conventional strategies.
Performance predictions for parallel diagonal-implicitly iterated Runge-Kutta methods
Authors: Thomas Rauber, Gudula Rünger
Venue: Proceedings of the ninth workshop on Parallel and distributed simulation (1995)

Many simulations in the natural sciences and engineering require the numerical solution of nonlinear differential equations. For this class of numerical methods, we propose an appropriate parallel computation model on distributed memory machines that supports the prediction of execution times. As a case study, we investigate the parallel implementation of the diagonal-implicitly iterated Runge-Kutta method, a solution method for stiff systems of ordinary differential equations. An implementation on the Intel iPSC/860 confirms the accuracy of the prediction model.