ppxscal/embedding_network huggingface dataset:
Multipoint Pad&eacute; approximation using a rational block Lanczos algorithm
Authors: Tuyen V. Nguyen, Jing Li
Venue: Proceedings of the 1997 IEEE/ACM international conference on Computer-aided design (1997)

This paper presents a general rational block Lanczos algorithm for computing multipoint matrix Pade approximation of linear multiport networks, which model many important circuits in digital, analog, or mixed signal designs. This algorithm generalizes a novel block Lanczos algorithm with a reliable adaptive scheme for breakdown treatment to address two drawbacks of the single frequency Pade approximation: poor approximation of the transfer function in the frequency domain far away from the expansion point and the instability of the reduced model when the original system is stable. In addition, due to smaller Krylov subspace corresponding to each frequency point, the rational algorithm also alleviates the possible breakdowns when completing high order approximations. The cost of full backward orthogonalization with respect to all previous Lanczos vectors in a rational Lanczos algorithm, as compared to a partial backward orthogonalization in a single point Lanczos algorithm, is offset by more accurate and smaller order approximations.
Time-Marching Algorithms for Nonlocal Evolution Equations Based Upon "Approximate Approximations"
Authors: Vladimir Karlin, Vladimir Maz'ya
Venue: SIAM Journal on Scientific Computing (1997)

New time-marching algorithms for solving initial value problems for nonlocal evolution equations are described. With respect to the space variable the discretization is based on a method of "approximate approximation" proposed by the second author. In time the algorithms are finite-difference schemes of either the first or the second approximation order, whereas with respect to the space variables we use "approximate approximations" of an arbitrary high order. The algorithms are stable under mild restrictions to the time step which come from the nonlinear part of the equation. Some computational results and hints on crucial implementation issues are provided.
A Homotopy Approach to Solving Nonlinear Rational Expectation Problems
Authors: Mark J. Jensen
Venue: Computational Economics (1997)

Many numerical methods have been developed in an attempt to find solutions to nonlinear rational expectations models. Because these algorithms are numerical in nature, they rely heavily on computing power and take sizeable cycles to solve. In this paper we present a numerical tool known as homotopy theory that can be applied to these methods. Homotopy theory reduces the computing time associated with an iterative algorithm by using a rational expectation problem with known solutions and transforming it into the problem at hand. If this transformation is performed slowly, homotopy theory also helps the global convergence properties of the numerical algorithm. We apply homotopy theory to Den Haan and Marcet&lsquo;s Parameterized Expectation Approach to show how homotopies improve the computing speed and global convergence properties of this algorithm.
Single Chip Dual&ndash;Issue RISC Processor for Real&ndash;Time MPEG&ndash;2 Software Decoding
Authors: Edgar Holmann, Toyohiko Yoshida, Akira Yamada, Shin-Ichi Uramoto
Venue: Journal of VLSI Signal Processing Systems (1998)

A single chip system for real&ndash;time MPEG&ndash;2 decoding can be created by integrating a general purpose dual&ndash;issue RISC processor, with a small dedicated hardware for the variable length decoding (VLD) and block loading processes; a 32KB instruction RAM; and a 32KB data RAM. The VLD hardware performs Huffman decoding on the input data. The block loader performs the half&ndash;sample prediction for motion compensation and acts as a direct memory access (DMA) controller for the RISC processor by transferring data between an external 2MB DRAM and the internall 32 KB data RAM. The dual-issue RISC processor, running at 250MHz, is enhanced with a set of key sub-word and multimedia instructions for a sustained peak performance of 1000 MOPS. With this setup for MPEG-2 decoding applications, bi-directionally predicted non-intra video blocks are decoded in less than 800 cycles, leading to a single-chip, real-time MPEG-2 decoding system.
The Structure of Random Graph Orders
Authors: Béla Bollobás, Graham Brightwell
Venue: SIAM Journal on Discrete Mathematics (1997)

The random graph order $P_{n,p}$ is defined by taking a random graph $G_{n,p}$ on vertex set $[n]$, treating an edge $ij$ with $i\prec j$ in $[n]$ as a relation $i
Noise-tolerant distribution-free learning of general geometric concepts
Authors: Nader H. Bshouty, Sally A. Goldman, H. David Mathias, Subhash Suri, Hisao Tamaki
Venue: Journal of the ACM (JACM) (1998)

We present an efficient algorithm for PAC-learning a very general class of geometric concepts over R d for fixed d. More specifically, let T be any set of s halfspaces. Let x =(x1, &hellip;, xd) be an arbitrary point in R d. With each t&isin;T we associate a boolean indicator function It(x) which is 1 if and only if x is in the halfspace t. The concept class, Cds , that we study consists of all concepts formed by any Boolean function over It1, &hellip;, Its for ti &isin;T . This class is much more general than any geometric concept class known to be PAC-learnable. Our results can be extended easily to learn efficiently any Boolean combination of a polynomial number of concepts selected from any concept class C over R given that the VC-dimension of C has dependence only on d and there is a polynomial time algorithm to determine if there is a concept from C consistent with a given set of labeled examples. We also present a statistical query version of our algorithm that can tolerate random classification noise. Finally we present a generalization of the standard &egr;-net result of Haussler and Welzl [1987] and apply it to give an alternative noise-tolerant algorithm for d = 2 based on geometric subdivisions.
Experimental evaluation of confidence interval procedures in sequential steady-state simulation
Authors: Donald C. McNickle, Krzysztof Pawlikowski, Gregory Ewing
Venue: Proceedings of the 28th conference on Winter simulation (1996)

Sequential analysis of simulation output is generally accepted as the most efficient way for securing representativeness of samples of collected observations. In this scenario a simulation experiment is stopped when the relative precision of estimates, defined as the relative width of confidence intervals at an assumed confidence level, reaches the required level. This paper deals with the statistical correctness of the methods proposed for estimating confidence intervals for mean values in sequential steady-state stochastic simulation. We formulate basic rules that should be followed in proper experimental analysis of coverage of different steady state interval estimators. Our main argument is that such analysis should be done sequentially. The numerical results of our preliminary coverage analysis of the method of Spectral Analysis (SA/HW) and Non overlapping Batch Means are presented, and compared with those obtained by traditional, non-sequential approaches.
Image Compression and Transmission Through a Low-RateUltrasonic Link in Subsea Telerobotic Applications
Authors: Shi Yin, Jens G. Balchen
Venue: Journal of Mathematical Imaging and Vision (1997)

This paper describes a progressive data compression algorithm for subsea gray-level image (data) transmission through a low rate ultrasonic link in a telerobotics system. The proposed image compression algorithm is based on JPEG, and has been modified for a specific subsea application, where the communication bit rate is confined to 100&ndash;200 bits/s and a frequent updating of reconstructed images is required.The experimental result based on 23 real images shows that the proposed image data compression algorithm performs better than JPEG when images are reconstructed from a small amount of data. The transmission error effect and computational complexity have also been analysed with respect to the proposed algorithm.
Computational geometry column 32
Authors: Joseph O'Rourke
Venue: ACM SIGACT News (1997)

The proof of Dey's new k-set bound is illustrated.
Personal thoughts on Ada's object orientation
Authors: Bob Mathis
Venue: Proceedings of the conference on TRI-ADA '90 (1990)

Ada's original design incorporated some of the best concepts of object-oriented programming in the context of its design objectives and the Steelman requirements. Only minor modifications are required to give Ada even more power. Drastic changes to make Ada more like some of the dynamic object-oriented programming languages would be inappropriate. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Hierarchical distributed reference counting
Authors: Luc Moreau
Venue: Proceedings of the 1st international symposium on Memory management (1998)

Massively distributed computing is a challenging problem for garbage collection algorithm designers as it raises the issue of scalability. The high number of hosts involved in a computation can require large tables for reference listing, whereas the lack of information sharing between hosts in a same locality can entail redundant GC traffic. In this paper, we argue that a conceptual hierarchical organisation of massive distributed computations can solve this problem. By conceptual hierarchical organisation, we mean that processors are still able to communicate in a peer to peer manner using their usual communication mechanism, but GC messages will be routed as if processors were organised in hierarchy. We present an extension of a distributed reference counting algorithm that uses such a hierarchical organisation. It allows us to bound table sizes by the number of hosts in a domain, and it allows us to share GC information between hosts in a same locality in order to reduce cross-network GC traffic.
Report from the NSF workshop on workflow and process automation in information systems
Authors: Amit Sheth, Dimitrios Georgakopoulos, Stef M. M. Joosten, Marek Rusinkiewicz, Walt Scacchi, Jack Wileden, Alexander L. Wolf
Venue: ACM SIGSOFT Software Engineering Notes (1997)

An interdisciplinary research community needs to address challenging issues raised by applying workflow management technology in information systems. This conclusion results from the NSF workshop on Workflow and Process Automation in Information Systems which was held at the State Botanical Garden of Georgia during May 8-10, 1996. The workshop brought together active researchers and practitioners from several communities, with significant representation from database and distributed systems, software process and software engineering, and computer supported cooperative work. The presentations given at the workshop are available in the form of an electronic proceedings of this workshop at http://lsdis.cs.uga.edu/activities/). This report is the joint work of selected representatives from the workshop and it documents the results of significant group discussions and exchange of ideas.
Efficient Self-Embedding of Butterfly Networks with Random Faults
Authors: Hisao Tamaki
Venue: SIAM Journal on Computing (1998)

We study the embedding of the butterfly network in its faulty version, where each node is independently faulty with some constant probability $p$. We give a method of such self-embedding of the N-node butterfly with O(1) load, O((log log N)2.6) dilation, and O((log log N)c) congestion, which succeeds with probability at least 1 - N-1 if p c is a constant that depends on p; c is about 8.84 for p = 0.1 and approaches log2 40 \simeq 5.32$ as $p \rightarrow 0$. The method is constructive and in fact yields an N logO(1) N time deterministic algorithm to construct the claimed embedding with the claimed success probability when given the random faulty butterfly. We also show that we can make the dilation as low as O(log log N), although at the cost of logO(1) N congestion. These embeddings are level-preserving in the sense that each node is mapped to a node in the same level of the butterfly as the original node. We also derive a lower bound of log log N - o(log log N) on the dilation of a level-preserving embedding with $N^\alpha$ load, for any constant $\alpha p > 0. Thus, the bounds on dilation are tight up to a constant factor, as far as level-preserving embeddings are concerned.
Optimization techniques for high-performance digital circuits
Authors: Chandu Visweswariah
Venue: Proceedings of the 1997 IEEE/ACM international conference on Computer-aided design (1997)

The relentless push for high performance in custom digital circuits has led to renewed emphasis on circuit optimization or tuning. The parameters of the optimization are typically transistor and interconnect sizes. The design metrics are not just delay, transition times, power and area, but also signal integrity and manufacturability. This tutorial paper discusses some of the recently proposed methods of circuit optimization, with an emphasis on practical application and methodology impact. Circuit optimization techniques fall into three broad categories. The first is dynamic tuning, based on time-domain simulation of the underlying circuit, typically combined with adjoint sensitivity computation. These methods are accurate but require the specification of input signals, and are best applied to small data-flow circuits and "cross-sections" of larger circuits. Efficient sensitivity computation renders feasible the tuning of circuits with a few thousand transistors. Second, static tuners employ static timing analysis to evaluate the performance of the circuit. All paths through the logic are simultaneously tuned, and no input vectors are required. Large control macros are best tuned by these methods. However, in the context of deep submicron custom design, the inaccuracy of the delay models employed by these methods often limits their utility. Aggressive dynamic or static tuning can push a circuit into a precipitous corner of the manufacturing process space, which is a problem addressed by the third class of circuit optimization tools, statistical tuners. Statistical techniques are used to enhance manufacturability or maximize yield. In addition to surveying the above techniques, topics such as the use of state-of-the-art nonlinear optimization methods and special considerations for interconnect sizing, clock tree optimization and noise-aware tuning will be briefly considered.
Relative Liveness: From Intuition to Automated Verification
Authors: R. Negulescu, J. A. Brzozowski
Venue: Formal Methods in System Design (1998)

We define a new liveness condition for asynchronous circuits. Although finitary (finite-execution) descriptions are not powerful enough to express general liveness properties, those liveness properties needed in practice appear to be related in a unique manner to finitary descriptions. Our liveness condition exploits this observation and is defined directly on finitary descriptions, in two forms: one on finite trace structures and the other on finite automata. We prove the equivalence of these two forms. We also introduce a safety condition and derive theorems for the modular and hierarchical verification theorems of both safety and liveness. Finally, we give an algorithm for verifying our liveness condition.
Local Convergence of the Symmetric Rank-One Iteration
Authors: C. T. Kelley, E. W. Sachs
Venue: Computational Optimization and Applications (1998)

We consider conditions under which the SR1 iteration is locally convergent. We apply the result to a pointwise structured SR1 method that has been used in optimal control.
Science and engineering case studies in introductory computing courses for non-majors
Authors: David L. Spooner, Michael Skolnick
Venue: ACM SIGCSE Bulletin (1997)

This paper relates experience in exploiting a science and engineering case study approach to teach introductory computing concepts in a course for non-majors. It describes how a case study is structured and implemented using hypermedia. It also discusses experience gained in using the case studies in the course.
Extended shared-variable sessions
Authors: Karl Soop, Roderic A. Davis,  II
Venue: ACM SIGAPL APL Quote Quad (1985)

This paper proposes two extensions to make shared variables of APL more useful: Shared variables that persist across APL sessions, and a facility to reject incoming offers.
Use of RESOURCE blocks in SLAM II for the evaluation of operator-machine assignments
Authors: Lynn S. Lachenmaier, Jeffery K. Cochran
Venue: Proceedings of the 28th conference on Winter simulation (1996)

This paper examines the problem of assigning jobs to a set of manufacturing machine operators. This classic problem involves a set of semi-skilled personnel who can run subsets of machinery. The number of operators assigned to groups of machinery can be varied to optimize throughput. While the operator-machine problem has been studied in previous literature using a wide variety of analytical algorithms, we look at a solution that uses the RESOURCE block in SLAM II to simulate possible operator-machine combinations. A semiconductor fabrication facility was modeled using the operators as resources, and four alternate assignments were compared. Our concept for developing a simulation model of this problem in SLAM II proved to be an effective way to evaluate operator-machine assignments.
An Analytic-to-Holistic Approach for Face Recognition Based on a Single Frontal View
Authors: Kin-Man Lam, Hong Yan
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1998)

In this paper, we propose an analytic-to-holistic approach which can identify faces at different perspective variations. The database for the test consists of 40 frontal-view faces. The first step is to locate 15 feature points on a face. A head model is proposed, and the rotation of the face can be estimated using geometrical measurements. The positions of the feature points are adjusted so that their corresponding positions for the frontal view are approximated. These feature points are then compared with the feature points of the faces in a database using a similarity transform. In the second step, we set up windows for the eyes, nose, and mouth. These feature windows are compared with those in the database by correlation. Results show that this approach can achieve a similar level of performance from different viewing directions of a face. Under different perspective variations, the overall recognition rates are over 84 percent and 96 percent for the first and the first three likely matched faces, respectively.
Learning to Understand Information on the Internet: AnExample-Based Approach
Authors: Mike Perkowitz, Robert B. Doorenbos, Oren Etzioni, Daniel S. Weld
Venue: Journal of Intelligent Information Systems (1997)

The explosive growth of the Web has made intelligent software assistants increasingly necessary for ordinary computer users. Both traditional approaches&mdash;search engines, hierarchical indices&mdash;and intelligent software agents require significant amounts of human effort to keep up with the Web. As an alternative, we investigate the problem of automatically learning to interact with information sources on the Internet. We report on ShopBot and ILA , two implemented agents that learn to use such resources. ShopBot learns how to extract information from online vendors using only minimal knowledge about product domains. Given the home pages of several online stores, ShopBot autonomously learns how to shop at those vendors. After its learning is complete, ShopBot is able to speedily visit over a dozen software stores and CD vendors, extract product information, and summarize the results for the user. ILA learns to translate information from Internet sources into its own internal concepts. ILA builds a model of an information source that specifies the translation between the source&lsquo;s output and ILA &lsquo;s model of the world. ILA is capable of leveraging a small amount of knowledge about a domain to learn models of many information sources. We show that ILA &lsquo;s learning is fast and accurate, requiring only a small number of queries per information source.
Self-Calibration of a Moving Camera from PointCorrespondences and Fundamental Matrices
Authors: Q.-T. Luong, O. D. Faugeras
Venue: International Journal of Computer Vision (1997)

We address the problem of estimating three-dimensional motion, and structure from motion with an uncalibrated moving camera. We show that point correspondences between three images, and the fundamental matrices computed from these point correspondences, are sufficient to recover the internal orientation of the camera (its calibration), the motion parameters, and to compute coherent perspective projection matrices which enable us to reconstruct 3-D structure up to a similarity. In contrast with other methods, no calibration object with a known 3-D shape is needed, and no limitations are put upon the unknown motions to be performed or the parameters to be recovered, as long as they define a projective camera.The theory of the method, which is based on the constraint that the observed points are part of a static scene, thus allowing us to link the intrinsic parameters and the fundamental matrix via the absolute conic, is first detailed. Several algorithms are then presented, and their performances compared by means of extensive simulations and illustrated by several experiments with real images.
The correlation between mean and variance estimators
Authors: Keebom Kang, David Goldsman
Venue: Proceedings of the 17th conference on Winter simulation (1985)

One of the pitfalls encountered when using confidence interval estimators for the mean of a stationary stochastic process is that the mean and variance estimators (X and V) may be correlated. We derive Corr (X, V) for various variance estimators and stochastic processes, and we examine the effects of this correlation upon confidence interval estimator performance. Among the variance estimators under consideration are those arising from the methods of batched means and standardized time series. Both small sample and asymptotic results are reported.
Secure group communications using key graphs
Authors: Chung Kei Wong, Mohamed Gouda, Simon S. Lam
Venue: ACM SIGCOMM Computer Communication Review (1998)

Many emerging applications (e.g., teleconference, real-time information services, pay per view, distributed interactive simulation, and collaborative work) are based upon a group communications model, i.e., they require packet delivery from one or more authorized senders to a very large number of authorized receivers. As a result, securing group communications (i.e., providing confidentiality, integrity, and authenticity of messages delivered between group members) will become a critical networking issue.In this paper, we present a novel solution to the scalability problem of group/multicast key management. We formalize the notion of a secure group as a triple (U,K,R) where U denotes a set of users, K a set of keys held by the users, and R a user-key relation. We then introduce key graphs to specify secure groups. For a special class of key graphs, we present three strategies for securely distributing rekey messages after a join/leave, and specify protocols for joining and leaving a secure group. The rekeying strategies and join/leave protocols are implemented in a prototype group key server we have built. We present measurement results from experiments and discuss performance comparisons. We show that our group key management service, using any of the three rekeying strategies, is scalable to large groups with frequent joins and leaves. In particular, the average measured processing time per join/leave increases linearly with the logarithm of group size.