ppxscal/embedding_network huggingface dataset:
Sparse Linear Least Squares Problems in Optimization
Authors: Pontus Matstoms
Venue: Computational Optimization and Applications (1997)

Numerical and computational aspects of direct methods for large and sparse least squares problems are considered. After a brief survey of the most often used methods, we summarize the important conclusions made from a numerical comparison in matlab. Significantly improved algorithms have during the last 10-15 years made sparse QR factorization attractive, and competitive to previously recommended alternatives. Of particular importance is the multifrontal approach, characterized by low fill-in, dense subproblems and naturally implemented parallelism. We describe a Householder multifrontal scheme and its implementation on sequential and parallel computers. Available software has in practice a great influence on the choice of numerical algorithms. Less appropriate algorithms are thus often used solely because of existing software packages. We briefly survey software packages for the solution of sparse linear least squares problems. Finally, we focus on various applications from optimization, leading to the solution of large and sparse linear least squares problems. In particular, we concentrate on the important case where the coefficient matrix is a fixed general sparse matrix with a variable diagonal matrix below. Inner point methods for constrained linear least squares problems give, for example, rise to such subproblems. Important gains can be made by taking advantage of structure. Closely related is also the choice of numerical method for these subproblems. We discuss why the less accurate normal equations tend to be sufficient in many applications.
An Extended Dominating Node Approach to Broadcast and Global Combine in Multiport Wormhole-Routed Mesh Networks
Authors: Yih-jia Tsai, Philip K. McKinley
Venue: IEEE Transactions on Parallel and Distributed Systems (1997)

A new approach to the design of collective communication operations in wormhole-routed mesh networks is described. The approach extends the concept of dominating sets in graph theory by accounting for the relative distance-insensitivity of the wormhole switching strategy and by taking advantage of a multiport communication architecture, which allows each node to simultaneously transmit messages on different outgoing channels. Collective communication operations are defined in terms of sets of extended dominating nodes (EDNs). The nodes in a set of EDNs can deliver (receive) messages to (from) a different, larger set of nodes in a single message-passing step under dimension-ordered wormhole routing and without channel contention among messages. The EDN model can be applied to different collective operations in 2D and 3D mesh networks. In this paper, we focus on EDN-based broadcast and global combine operations. Performance evaluation results are presented that confirm the advantage of this approach over other methods.
Mathematics education through the perspective of rationalized APL
Authors: Linda Alvord
Venue: ACM SIGAPL APL Quote Quad (1985)

Mathematics expresses concepts by the use of a symbol system. The symbols include the familiar plus + , minus - , times x and divide &divide; . APL extends the conventional mathematical symbol system to include major ideas such as power, maximum and deal. These powerful ideas are expressed in simple APL symbols like *, &lceil;, and ?. These functions require two arguments represented by the two Greek letters alpha and omega. They are generalized with the expressions &agr;*&ogr; &agr;&lceil;&ogr; and &agr;?&ogr;. The symbols have functions which are monadic counterparts called exponential, ceiling and roll when they have only one argument as in *&ogr;, &lceil;&ogr; and ?&ogr;. The mind comprehends and manipulates increasingly complex concepts expressed in these abstract symbols. New thoughts and ideas are generated in response. On occasion, new concepts warrant symbols of their own. This paper demonstrates a strategy for teaching students the process of developing an extended symbol system of their own. In education, teachers help learners to read and interpret what already exists. In addition, just as writers learn by expressing concepts in their own sentences, mathematicians need to experiment with the process of &ldquo;symbol building&rdquo; to learn the essential nature of mathematics. The example which follows shows the development of a &ldquo;meaning&rdquo; for the symbol. In the monadic case, &ogr;, the function produces a frequency distribution of the elements in the numeric array argument. In the dyadic case, &agr; &ogr;, the result is a frequency distribution of the elements in the literal array argument entered in &ogr; which are contained in the array provided in &agr;. Implementing the method requires both direct definition and Rationalized APL by Kenneth Iverson which proposes the use of the del operator to allow the APL user to make a function represented by a single symbol. The del operator creates a function which has both a monadic and a dyadic definition and consequently is called ambivalent. Learning to use these tools allows the student to experiment as a creator of mathematical language.
Hybrid spectral/iterative partitioning
Authors: Jason Y. Zien, Pak K. Chan, Martine Schlag
Venue: Proceedings of the 1997 IEEE/ACM international conference on Computer-aided design (1997)

We develop a new multi-way, hybrid spectral/iterative hypergraph partitioning algorithm that combines the strengths of spectral partitioners and iterative improvement algorithms to create a new class of partitioners. We use spectral information (the eigenvectors of a graph) to generate initial partitions, influence the selection of iterative improvement moves, and break out of local minima. Our 3-way and 4-way partitioning results exhibit significant improvement over current published results, demonstrating the effectiveness of our new method. Our hybrid algorithm produces an improvement of 25% over GFM for 3-way partitions, 41% improvement over GFM for 4-way partitions, and 58% improvement over ML_F for 4-way partitions.
Wire segmenting for improved buffer insertion
Authors: Charles Alpert, Anirudh Devgan
Venue: Proceedings of the 34th annual Design Automation Conference (1997)

Buffer insertion seeks to place buffers on the wires of a signal netto minimize delay. Van Ginneken [Buffer Placement in Distributed RC-tree Networks for Minimal Elmore Delay] proposed an optimal dynamicprogramming solution (with extensions proposed by [7] [8][9] [12]) such that at most one buffer can be placed on a singlewire. This constraint can hurt solution quality, but it may be circumventedby dividing each wire into multiple smaller segments.This work studies the problem of finding the correct number of segmentsfor each wire in the routing tree. Too few segments yieldssub-par solutions, but too many segments can lead to excessive runtimes and memory loads. We derive new theoretical results forcomputing the appropriate number of buffers (and hence wire segments)which motivate our new wire segmenting algorithm. Weshow that using wire segmenting as a precursor to buffer insertionproduces solutions within a few percent of optimal, while usingonly seconds of CPU time.
Validation of correlation-induction strategies for simulation experiments
Authors: Jeffrey D. Tew, James R. Wilson
Venue: Proceedings of the 17th conference on Winter simulation (1985)

This paper develops a three-stage procedure for validating the use of the Schruben-Margolin correlation Induction strategy together with the follow-up analysis of Nozarl, Arnold, and Pegden in a simulation experiment designed to estimate a general linear model for the simulation response. Each stage of the procedure tests a key assumption about the behavior of the response across all points in the design. The first stage tests for multivariate normality, the second stage tests for the induced covariance structure postulated by Schruben and Margolin, and the third stage tests for the adequacy of the proposed linear model. Because the test in each stage presupposes the properties tested in previous stages, these diagnostic checks on the experimental design and analysis must be performed in the indicated order.
Power Optimization in VLSI Layout: A Survey
Authors: Massoud Pedram, Hirendu Vaishnav
Venue: Journal of VLSI Signal Processing Systems (1997)

This paper presents a survey of layout techniques for designing low power digital CMOS circuits. It describes the many issues facing designers at the physical level of design abstraction and reviews some of the techniques and tools that have been proposed to overcome these difficulties.
Simulation-based supply-chain optimization for consumer products
Authors: David R. Kalasky
Venue: Proceedings of the 28th conference on Winter simulation (1996)

This paper presents an application of discrete-event simulation in modeling a supply-chain for consumer products. Optimization of the simulation model provides an efficient way to produce operating recommendations from the model. The use of ProModel and SimRunner in this application describes a modeling and optimization software suite which can be used for supply-chain planning and operation.
Security and log structured file systems
Authors: Tage Stabell-Kulø
Venue: ACM SIGOPS Operating Systems Review (1997)

A log structured file system (LFS) obtains its performance by refraining from seeking for blocks on the disk. Instead, new data is written into new blocks which is placed at the end of the log. This incurs a security issue by leaving data on disk that was supposed to be overwritten.To us, this shows how difficult it is for users concerned with their privacy, not to be lead astray. It also emphasizes how wide the gap is between an encryption channel and a user.
Segmentation of Random Fields Via Borrowed Strength Density Estimation
Authors: Carey E. Priebe, David J. Marchette, George W. Rogers
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1997)

In many applications, spatial observations must be segmented into homogeneous regions and the number, positions, and shapes of the regions are unknown a priori. Information about the underlying probability distributions for observations in the various regions can be useful in such a procedure, but these distributions are often unknown. Furthermore, while there may be a large number of observations overall, the anticipated regions of interest may be small with few observations from the individual regions. This paper presents a technique designed to address these difficulties. A simple segmentation procedure can be obtained as a clustering of the disjoint subregions obtained through an initial low-level partitioning procedure. Clustering of these subregions based upon a similarity matrix derived from estimates of their marginal probability density functions yields the resultant segmentation. It is shown that this segmentation is improved through the use of a "borrowed strength" density estimation procedure wherein potential similarities between the density functions for the subregions are exploited. The borrowed strength technique is described and the performance of segmentation based on these estimates is investigated through an example from statistical image analysis.
Distributed advance reservation of real-time connections
Authors: Domenico Ferrari, Amit Gupta, Giorgio Ventre
Venue: Multimedia Systems (1997)

The ability to reserve real-time connections in advance is essential in all distributed multiparty applications(i.e., applications involving multiple human beings) usinga network that controls admissions to provide good quality of service. This paper discusses the requirements of theclients of an advance reservation service, and a distributeddesign for such a service. The design is described withinthe context of the Tenet Real-Time Protocol Suite 2, a suitebeing developed for multiparty communication, which willoffer advance reservation capabilities to its clients, based onthe principles and the mechanisms proposed in the paper.Simulation results providing useful data about the performance and some of the properties of these mechanisms arealso presented. We conclude that the one described here is aviable approach to constructing an advance reservation service within the context of the Tenet Suites as well as thatof other solutions to the multiparty real-time communicationproblem.
A Comparison of New and Old Algorithms for a Mixture EstimationProblem
Authors: David P. Helmbold, Robert E. Schapire, Yoram Singer, Manfred K. Warmuth
Venue: Machine Learning (1997)

We investigate the problem of estimating the proportion vector which maximizes the likelihood of a given sample for a mixture of given densities. We adapt a framework developed for supervised learning and give simple derivations for many of the standard iterative algorithms like gradient projection and EM. In this framework, the distance between the new and old proportion vectors is used as a penalty term. The square distance leads to the gradient projection update, and the relative entropy to a new update which we call the exponentiated gradient update (EG_\eta). Curiously, when a second order Taylor expansion of the relative entropy is used, we arrive at an update EM_\eta which, for \eta=1, gives the usual EM update. Experimentally, both the EM_{\eta}-update and the EG_\eta-update for \eta > 1 outperform the EM algorithm and its variants. We also prove a polynomial bound on the rate of convergence of the EG_\eta algorithm.
On the use of SPEC benchmarks in computer architecture research
Authors: Reinhold Weicker
Venue: ACM SIGARCH Computer Architecture News (1997)

Benchmarks, in particular the SPEC CPU benchmarks, are frequently used in academic computer research. With ASPLOS-7 as an example, observations about such usage are reported, and suggestions are made for a meaningful use of benchmarks in computer architecture research. Forward-looking computer architecture research may need more than one benchmark collection.
Introduction to SANDIE
Authors: Arne Thesen
Venue: Proceedings of the 17th conference on Winter simulation (1985)

This paper gives a short introduction to SANDIE, a statistical data analysis system designed to run on the IBM-PC and similar computers. Special care was made in the development of SANDIE to design a system that would serve as an aid in the development of an intuitive &ldquo;sense of numbers&rdquo;. This goal was achieved by providing very fast response times, easy to use graphics and commands that encourage the casual exploration of properties of data sets.
Hmap: a fast mapper for EPGAs using extended GBDD hash tables
Authors: Cheng-Hsing Yang, Chia-Chun Tsai, Jan-Ming Ho, Sao-Jie Chen
Venue: ACM Transactions on Design Automation of Electronic Systems (TODAES) (1997)

A fast and efficient algorithm for technology mapping of electrically programmable gate arrays (EPGAs) is proposed. This Hmap algorithm covers the Boolean network with programmed logic modules bottom-up. The covering operation is based on collapsing the fanins of a node to form a bigger supernode such that fewer clusters are needed to be detected. Then Boolean matching is used to detect whether the collapsed supernode can be mapped into a logic module by looking up an extended GBDD hash table. The use of this table look-up matching can shorten the matching time significantly. As shown in the experiments, the average running time of Hmap is 20 times faster than that of MIS-pga2.
REDLOG: computer algebra meets computer logic
Authors: Andreas Dolzmann, Thomas Sturm
Venue: ACM SIGSAM Bulletin (1997)

REDLOG is a package that extends the computer algebra system REDUCE to a computer logic system, i.e., a system that provides algorithms for the symbolic manipulation of first-order formulas over some temporarily fixed language and theory. In contrast to theorem provers, the methods applied know about the underlying algebraic theory and make use of it. We illustrate some applications of REDLOG, describe its functionality as it appears to the user, and explain the design issues and implementation techniques. REDLOG is available on the WWW.
Using generational garbage collection to implement cache-conscious data placement
Authors: Trishul M. Chilimbi, James R. Larus
Venue: Proceedings of the 1st international symposium on Memory management (1998)

The cost of accessing main memory is increasing. Machine designers have tried to mitigate the consequences of the processor and memory technology trends underlying this increasing gap with a variety of techniques to reduce or tolerate memory latency. These techniques, unfortunately, are only occasionally successful for pointer-manipulating programs. Recent research has demonstrated the value of a complementary approach, in which pointer-based data structures are reorganized to improve cache locality.This paper studies a technique for using a generational garbage collector to reorganize data structures to produce a cache-conscious data layout, in which objects with high temporal affinity are placed next to each other, so that they are likely to reside in the same cache block. The paper explains how to collect, with low overhead, real-time profiling information about data access patterns in object-oriented languages, and describes a new copying algorithm that utilizes this information to produce a cache-conscious object layout.Preliminary results show that this technique reduces cache miss rates by 21--42%, and improves program performance by 14--37% over Cheney's algorithm. We also compare our layouts against those produced by the Wilson-Lam-Moher algorithm, which attempts to improve program locality at the page level. Our cache-conscious object layouts reduces cache miss rates by 20--41% and improves program performance by 18--31% over their algorithm, indicating that improving locality at the page level is not necessarily beneficial at the cache level.
Integrating Multiple Learning Strategies in First Order Logics
Authors: A. Giordana, F. Neri, L. Saitta, M. Botta
Venue: Machine Learning (1997)

This paper describes a representation framework that offers a unifying platform for alternative systems, which learn concepts in First Order Logics. The main aspects of this framework are discussed. First of all, the separation between the hypothesis logical language (a version of the VL21 language) and the representation of data by means of a relational database is motivated. Then, the functional layer between data and hypotheses, which makes the data accessible by the logical level through a set of abstract properties is described. A novelty, in the hypothesis representation language, is the introduction of the construct of internal disjunction; such a construct, first used by the AQ and Induce systems, is here made operational via a set of algorithms, capable to learn it, for both the discrete and the continuous-valued attributes case. These algorithms are embedded in learning systems (SMART+, REGAL, SNAP, WHY, RTL) using different paradigms (symbolic, genetic or connectionist), thus realizing an effective integration among them; in fact, categorical and numerical attributes can be handled in a uniform way. In order to exemplify the effectiveness of the representation framework and of the multistrategy integration, the results obtained by the above systems in some application domains are summarized.
Graduate software engineering across international boundaries (poster): the first courses
Authors: James Wolfer
Venue: Proceedings of the 6th annual conference on the teaching of computing and the 3rd annual conference on Integrating technology into computer science education: Changing the delivery of computer science education (1998)

The combined influences funding education and the availability of international communication has brought distance education to the forefront of educational efforts. This report describes the integration of the fist Software Engineering course with an initial group project, and the subsequent management of quality across culture, time, and distance.
A hierarchical decomposition methodology for multistage clock circuits
Authors: Gary Ellis, Lawrence T. Pileggi, Rob A. Rutenbar
Venue: Proceedings of the 1997 IEEE/ACM international conference on Computer-aided design (1997)

This paper describes a novel methodology to automate the design of the interconnect distribution for multistage clock circuits. We introduce two key ideas. First, a hierarchical decomposition of the layout divides the problem into a set of local Steiner-wired latch clusters (to minimize and balance local capacitance) fed globally by a balanced binary tree (to maximize performance). Second, we recast the global clock distribution problem as a simultaneous optimization of clock topology, clock segment routing, wiresizing, and buffering. The hierarchical decomposition reduces the problem complexity and allows use of more aggressive optimization techniques. Integration of the geometric and electrical optimizations likewise allows more aggressive performance goals. Experiments with an industrial design comprising over 16,000 latches demonstrate the efficiency of the approach: a complete clock distribution solution met a 200MHz cycle time specification with only 310ps of skew, met strict current density constraints, exhibited good delay matching across uniform wire width and device variations, and was completed in under 10 CPU hours.
Methodological issues for the design of an office information server: focal topics for the analysis from an office system perspective
Authors: T. Truckenmüller, M. Rathgeb
Venue: Proceedings of the 9th annual international ACM SIGIR conference on Research and development in information retrieval (1986)

This paper deal with the necessity of consideration of organizational and user requirements to create the basis for the successful design of future office information servers. Today volumes of the order of 10.000 to 50.000 multimode documents and 1 to 10 million documents at a company level (companies with over 1000 employees) per system have to be archived. The average amount of filing is 12 to 16 running metres of paper per year, with an increasing tendency (Ben84). However the shortcoming of systems of today is not the incapability of storage of big amounts of information but the fact they only support particular (and well structured) office tasks in an operative way. Future systems have to support all kind of work (procedures) people do in an office, consider the strategic and operative goals of the particular office and take the user behaviours especially their knowledge to solve problems and the individual kind of doing their jobs (e.g. search strategies, reminder functions) into account. Analysis methods for the collection of data for the design of office systems have mostly been developed in the context of office automation to develop systems to support particular tasks, to restructure offices to improve the profitability of the company. Because of that fact, these methods must be quite extended to supply data which are suited for the successful design and development of future office information servers. Focal topics of the analysis from an office system perspective are: information generation and location, consistency and permanence, work support, information handling and manipulation, access right and confidentiality, accountability, information flow and use of abstractions. Detailed dimensions concerning these areas are posted in this paper.