ppxscal/embedding_network huggingface dataset:
ALPHA/SIM simulation software tutorial
Authors: Kendra E. Moore, John E. Brennan
Venue: Proceedings of the 28th conference on Winter simulation (1996)

ALPHA/Sim is a general-purpose, discrete-event simulation tool. ALPHA/Sim allows a user to graphically build a simulation model, enter input data via integrated forms, execute the simulation model, and view the simulation results, within a single graphical environment. In this paper, we introduce ALPHA/Sim and describe how to use ALPHA/Sim to build, simulate, and analyze a simple manufacturing system. In addition, we briefly describe some advanced features and list some sample applications.
Universal Hashing and Geometric Codes
Authors: Jürgen Bierbrauer
Venue: Designs, Codes and Cryptography (1997)

We describe a new application of algebraic coding theory to universal hashing and authentication without secrecy. This permits to make use of the hitherto sharpest weapon of coding theory, the construction of codes from algebraic curves. We show in particular how codes derived from Artin-Schreier curves, Hermitian curves and Suzuki curves yield classes of universal hash functions which are substantially better than those known before.
Scalable high speed IP routing lookups
Authors: Marcel Waldvogel, George Varghese, Jon Turner, Bernhard Plattner
Venue: ACM SIGCOMM Computer Communication Review (1997)

Internet address lookup is a challenging problem because of increasing routing table sizes, increased traffic, higher speed links, and the migration to 128 bit IPv6 addresses. IP routing lookup requires computing the best matching prefix, for which standard solutions like hashing were believed to be inapplicable. The best existing solution we know of, BSD radix tries, scales badly as IP moves to 128 bit addresses. Our paper describes a new algorithm for best matching prefix using binary search on hash tables organized by prefix lengths. Our scheme scales very well as address and routing table sizes increase: independent of the table size, it requires a worst case time of log2(address bits) hash lookups. Thus only 5 hash lookups are needed for IPv4 and 7 for IPv6. We also introduce Mutating Binary Search and other optimizations that, for a typical IPv4 backbone router with over 33,000 entries, considerably reduce the average number of hashes to less than 2, of which one hash can be simplified to an indexed array access. We expect similar average case behavior for IPv6.
Invariants of Families of Coplanar Conics and Their Applicationsto Object Recognition
Authors: Douglas R. Heisterkamp, Prabir Bhattacharya
Venue: Journal of Mathematical Imaging and Vision (1997)

This paper presents mutual invariants of families of coplanar conics. These invariants are compared with the use of invariants of two conics and a case is presented where the proposed invariants have a greater discriminating power than the previously used invariants. The use of invariants for two conics is extended to any number of coplanar conics. A lambda-matrix is associated with each family of coplanar conics. The use of lambda-matrices is extended from the single variable polynomial to multi-variable polynomials. The Segre characteristic and other invariants of the lambda-matrix are used as invariants of the family of conics.
Speculative parallel simulation with an adaptive throttle scheme
Authors: Seng Chuan Tay, Yong Meng Teo, Siew Theng Kong
Venue: Proceedings of the eleventh workshop on Parallel and distributed simulation (1997)

Excessive rollback recoveries due to overoptimistic event execution in Time Warp simulators often degrade their runtime performance. This paper presents a two-sided throttling scheme to dynamically adjust the event execution speed of Time Warp simulators. The proposed throttle is based on a new concept called global progress window, which allows the individual simulation process to be positioned on a global time scale, thereby to accelerate or suspend their event execution. As each simulation process can be throttled to a steady state, excessive rollback recoveries due to causality errors can be avoided. To quantify the effect of rollbacks and for purpose of comparing different Time Warp implementations, we propose two new measures called RPE (number of Rollback events Per committed Event), and E (relative Effectiveness in reducing rollback overhead). Our implementation results show that the proposed throttle effectively regulates the proceeding of each simulation process, resulting in a significant reduction in rollback thrashing and elapsed time.
Application-based modules using apprentice learning for CS 2
Authors: Owen Astrachan, Robert Smith, James Wilkes
Venue: ACM SIGCSE Bulletin (1997)

A typical Data Structures (CS 2) course covers a wide variety of topics: elementary algorithm analysis; data structures including dynamic structures, trees, tables, graphs, etc.; large programming projects; and more advanced object-oriented concepts. Integrating these topics into assignments is a challenging task; educators often duplicate work done by others in re-inventing such assignments. At the same time, these assignments and large programs take time to develop and are often changed from semester to semester to preclude cheating. We report on a project that provides modules containing many kinds of programming and lab assignments which can be re-used across semesters with accessible and exciting application-oriented materials. Our project is a collaboration between a research and teaching oriented private university, a teaching oriented public university, and a teaching oriented historically black university. This helps ensure that the modules will be accessible to nearly all student populations. The modules developed are available electronically as hyper-text documents.
High-level scheduling model and control synthesis for a broad range of design applications
Authors: Chih-Tung Chen, Kayhan Küçükçakar
Venue: Proceedings of the 1997 IEEE/ACM international conference on Computer-aided design (1997)

This paper presents a versatile scheduling model and an efficient control synthesis methodology which enables architectural (high-level) design/synthesis systems to seamlessly support a broad range of architectural design applications from datapath-dominated digital signal processing (DSP) to micro-processors/controllers and control-dominated peripherals, utilizing multi-phase clocking schemes, multiple threading, data-dependent delays, pipelining, and combinations of the above. The work presented in this paper is an enabling technology for high-level synthesis to go beyond traditional datapath-dominated DSP applications and to start becoming a viable and cost-effective design methodology for commodity ICs such as micro-processors/controllers and control-dominated peripherals.
Shape from Shading with Interreflections Under a Proximal Light Source: Distortion-Free Copying of an UnfoldedBook
Authors: Toshikazu Wada, Hiroyuki Ukida, Takashi Matsuyama
Venue: International Journal of Computer Vision (1997)

We address the problem of recovering the 3D shape of an unfolded book surface from the shading information in a scanner image. This shape-from-shading problem in a real world environment is made difficult by a proximal, moving light source, interreflections, specular reflections, and a nonuniform albedo distribution. Taking all these factors into account, we formulate the problem as an iterative, non-linear optimization problem. Piecewise polynomial models of the 3D shape and albedo distribution are introduced to efficiently and stably compute the shape in practice. Finally, we propose a method to restore the distorted scanner image based on the reconstructed 3D shape. The image restoration experiments for real book surfaces demonstrate that much of the geometric and photometric distortions are removed by our method.
On Orthogonal Double Covers of Graphs
Authors: Darryn E. Bryant, A. Khodkar
Venue: Designs, Codes and Cryptography (1998)

A transformation which allows us to obtain an orthogonal double cover of a graph G from any permutation of the edge set of G is described. This transformation is used together with existence results for self-orthogonal latin squares, to give a simple proof of a conjecture of Chung and West.
New Families of Semi-Regular Relative Difference Sets
Authors: James A. Davis, Jonathan Jedwab, Miranda Mowbray
Venue: Designs, Codes and Cryptography (1998)

We give two constructions for semi-regular relative difference sets (RDSs) in groups whose order is not a prime power, where the order u of the forbidden subgroup is greater than 2. No such RDSs were previously known. We use examples from the first construction to produce semi-regular RDSs in groups whose order can contain more than two distinct prime factors. For u greater than 2 these are the first such RDSs, and for u=2 we obtain new examples.
A SAT-based implication engine for efficient ATPG, equivalence checking, and optimization of netlists
Authors: Paul Tafertshofer, Andreas Ganz, Manfred Henftling
Venue: Proceedings of the 1997 IEEE/ACM international conference on Computer-aided design (1997)

The paper presents a flexible and efficient approach to evaluating implications as well as deriving indirect implications in logic circuits. Evaluation and derivation of implications are essential in ATPG, equivalence checking, and netlist optimization. Contrary to other methods, the approach is based on a graph model of a circuit's clause description called implication graph. It combines both the flexibility of SAT-based techniques and high efficiency of structure based methods. As the proposed algorithms operate only on the implication graph, they are independent of the chosen logic. Evaluation of implications and computation of indirect implications are performed by simple and efficient graph algorithms. Experimental results for various applications relying on implication demonstrate the effectiveness of the approach.
A Min--Max Theorem for Bisubmodular Polyhedra
Authors: Satoru Fujishige
Venue: SIAM Journal on Discrete Mathematics (1997)

For a family ${\cal F} \subseteq 3^E$ closed with respect to the reduced union and intersection and for a bisubmodular function $f: {\cal F}\rightarrow \mbox{\bf R}$ with $(\emptyset,\emptyset) \in \cal F$ and $f(\emptyset,\emptyset)=0$, the bisubmodular polyhedron associated with $({\cal F},f)$ is given by \[ {\rm P}_*(f)=\{x\,|\,x\in\mbox{\bf R}^E\quad \forall (X,Y)\in {\cal F}: x(X,Y)\le f(X,Y)\}, \] where $x(X,Y)=\sum_{e\in X}x(e)-\sum_{e\in Y}x(e)$. We show a min--max relation that characterizes the distance between ${\rm P}_*(f)$ and a given point $x^0$ with respect to the $l_1$ norm: for any vector $x^0\in\mbox{\bf R}^E$, \[ \left. \min\left\{\sum_{e\in E}|x(e)-x^0(e)|\, \right| \,x\in{\rm P}_*(f)\right\} =\max\{x^0(X,Y)-f(X,Y)\,|\,(X,Y)\in{\cal F}\}, \] where if $f$ is integer valued and $x^0$ is integral, then the minimum is attained by an integral $x\in{\rm P}_*(f)$. This is in a sense equivalent to but is in a nicer symmetric form than a min--max theorem of Cunningham and Green-Krótki [Combinatorica, 11 (1991), pp. 219--230] shown to be associated with $b$-matching degree-sequence polyhedra and generalizes the well-known min--max theorem concerning a vector reduction of polymatroids and submodular systems. We also give an application of the theorem to a separable convex optimization problem on bisubmodular polyhedra.
Analysis of ultrasonic Doppler velocity data obtained in models of stenosed carotid bifucations with irregular lesion surface
Authors: K. Kaluzynski, B. Lesniak, K. Mikolajczyk, D. Liepsch
Venue: Technology and Health Care (1997)

In this study properties are concerned of ultrasonic Doppler spectra recorded distal to an irregularity localised in the internal carotid artery of a true-to-scale elastic model of a severely stenosed carotid bifurcation. Four models differing in irregularity were obtained by melting graded holes in the original wax cast, about 5-7 mm distal to the bifurcation. Velocity data were collected using an HP Sonos 2500 ultrasonograph working in pulsed Doppler mode. The observed effect of the irregularity with respect to the smooth wall model consisted in: (1) presence of a reduced flow zone 15 mm distal to the severe irregularity situated at the outer wall of the model in the ICA branch; (2) presence of a recirculation zone 15 mm distal to the severe irregularity situated at the inner wall of this model semi; (3) negative values of the measure of symmetry of the Doppler spectrum and (4) decreased values of relative width of Doppler spectra obtained 25 mm distal to the bifurcation in models with severe irregularity. The alterations of flow distribution and Doppler spectra depend on the geometry of the model under investigation and this study provides an indication as to what phenomena can happen in a model of stenosed carotid bifurcation with irregular lesion surface and how these phenomena may affect the ultrasonic Doppler spectra. Such information could be used in the evaluation of the risk of cerebral embolism.
Cache design with path balancing table, skewing and indirect tags
Authors: Tommi Jokinen, Chia-Jiu Wang
Venue: ACM SIGARCH Computer Architecture News (1997)

A cache design aimed to reduce cycle time, area, and miss rate simultaneously is proposed in this paper. A cache with path balancing table, skewing, and indirect tags can reduce cycle time, use less area, and reduce miss rate at the same time as compared with a baseline cache. From our simulation results, we propose cache design alternatives in achieving lower cycle time, lower miss rate, and using less area.
The role of VHDL in the MCC CAD system
Authors: Ramón D. Acosta, Mark Alexandre, Gary Imken, Bill Read
Venue: Proceedings of the 25th ACM/IEEE Design Automation Conference (1988)

The VHSIC Hardware Description Language (VHDL), currently undergoing standardization by the IEEE, supports the hierarchical design, documentation, and simulation of a wide range of digital system abstractions. This paper describes a suite of utilities for manipulating VHDL designs that has been developed and integrated into the CAD System of the Microelectronics and Computer Technology Corporation (MCC). The MCC CAD System is a tightly integrated environment supporting the sharing of design information between heterogeneous tools via an underlying knowledge base built on top of an object-oriented distributed database. The VHDL utilities include an editing mode to provide syntactic assistance for writing VHDL, an analyzer to produce intermediate representations, a compiler to translate the intermediate representations into directly executable LISP functions, an elaborator for generating simulation models from complete designs, and a simulator for these models. Experimentation, continued development, and several important extensions to the CAD System VHDL utilities are in progress.
Polynomial-Time Geometric Matching for Object Recognition
Authors: Todd A. Cass
Venue: International Journal of Computer Vision (1997)

This paper considers the task of recognition and position determination, by computer, of a 2D or 3D object where the input is a single 2D brightness image, and a model of the object is known a priori. The primary contribution of this paper is a novel formulation and methods for local geometric feature matching. This formulation is based on analyzing geometric constraints on transformations of the model features which geometrically align it with a substantial subset of image features. Specifically, the formulation and algorithms for geometric feature matching presented here provide a guaranteed method for finding all feasible interpretations of the data in terms of the model. This method is robust to measurement uncertainty in the data features and to the presence of spurious scene features, and its time and space requirements are only polynomial in the size of the feature sets. This formulation provides insight into the fundamental nature of the matching problem, and the algorithms commonly used in computer vision for solving it.
Program analysis: the abstract interpretation perspective
Authors: Patrick Cousot
Venue: ACM SIGPLAN Notices (1997)

Program analysis should evolve from a disparate collection of methods and algorithms to a mature discipline founded on a well-established methodology. Abstract interpretation can be used as a basis for such a methodology.
A Min-Max Theorem for a Constrained Matching Problem
Authors: Andreas Hefner
Venue: SIAM Journal on Discrete Mathematics (1997)

The following constrained matching problem arises in the area of manpower scheduling. Consider an undirected graph $G=(V,E)$ and a digraph $D=(V,A)$. A master/slave-matching (MS-matching) in $G$ with respect to $D$ is a matching in $G$ such that for each arc $(u,v)\in A$ for which the node $u$ is matched, the node $v$ is matched too. The problem is to find an MS-matching of maximum cardinality. This paper addresses the special case where $G$ is bipartite with bipartition $V=W\cup U$ and every (weakly) connected component of $D$ is either an isolated node or two nodes in $U$ which are joined by a single arc. The polyhedral structure of this special case is investigated and a min-max theorem which characterizes the cardinality of a maximum MS-matching in terms of the weight of a special node cover is derived. This min-max theorem includes as a special case the theorem of König.
Streamlining inter-operation memory communication via data dependence prediction
Authors: Andreas Moshovos, Gurindar S. Sohi
Venue: Proceedings of the 30th annual ACM/IEEE international symposium on Microarchitecture (1997)

We revisit memory hierarchy design viewing memory as an inter-operation communication agent. This perspective leads to the development of novel methods of performing inter-operation memory communication. We use data dependence prediction to identify and link dependent loads and stores so that they can communicate speculatively without incurring the overhead of address calculation, disambiguation and data cache access. We also use data dependence prediction to convert, DEF-store-load-USE chains within the instruction window into DEF-USE chains prior to address calculation and disambiguation. We use true and output data dependence status prediction to introduce and manage a small storage structure called the transient value cache (TVC). The TVC captures memory values that are short-lived. It also captures recently stored values that are likely to be accessed soon. Accesses that are serviced by the TVC do not have to be serviced by other parts of the memory hierarchy, e.g., the data cache. The first two techniques are aimed at reducing the effective communication latency whereas the last technique is aimed at reducing data cache bandwidth requirements. Experimental analysis of the proposed techniques shows that: the proposed speculative communication methods correctly handle a large fraction of memory dependences; and a large number of the loads and stores do not have to ever reach the data cache when the TVC is in place.
Raising NP lower bounds to parallel NP lower bounds
Authors: Edith Hemaspaandra, Lane A. Hemaspaandra Jörg Rothe
Venue: ACM SIGACT News (1997)

This issue's column surveys recent progress in raising NP-hardness lower bounds to parallel NP lower bounds. Complexity theorists will learn that Lewis Carroll (unbeknownst to himself) was a fellow complexity theorist. So that readers specializing in algorithms don't feel left out, let me mention that they are in even better company. Algorithms for apportioning the US House of Representatives were designed and debated by Adam, Hamilton, Jefferson, Webster, and other famous figures from American history, as recounted in a page-turner by Balinski and Young ([BY82]; see also [BY85] for a shorter take and [HRSZ96] for a more explicitly computational spin). Looking forward, the next issue's column will be a survey, by Mitsunori Ogihara, of DNA-based computing.
An Adaptive Mesh Projection Method for Viscous Incompressible Flow
Authors: Louis H. Howell, John B. Bell
Venue: SIAM Journal on Scientific Computing (1997)

Many fluid flow problems of practical interest---particularly at high Reynolds number---are characterized by small regions of complex and rapidly varying fluid motion surrounded by larger regions of relatively smooth flow. Efficient solution of such problems requires an adaptive mesh refinement capability to concentrate computational effort where it is most needed. We present in this paper a fractional step version of Chorin's projection method for incompressible flow, with adaptive mesh refinement, which is second-order accurate in both space and time. Convection terms are handled by a high-resolution upwind method which provides excellent resolution of small-scale features of the flow, while a multilevel iterative scheme efficiently solves the parabolic and elliptic equations associated with viscosity and the projection. Numerical examples demonstrate the performance of the method on two-dimensional problems involving vortex spindown with viscosity and inviscid vortex merger.
Ada: experience it again for the first time
Authors: Paul E. McMahon
Venue: Proceedings of the conference on TRI-ADA '90 (1990)

Many companies are beginning the transition to the DOD's new standard software language, Ada. Developing software with Ada requires new training for software engineers and changes to company software standards and procedures. Transitioning to Ada is not easy. Difficulties in using Ada stem from the language's complexity, changes in software methodology, and immaturity of first-generation compilers and software tools. Furthermore, developing Ada on a large project places its own special demands on the Ada programming support environment. Some of these Ada issues are not well known. In many cases, tools to support these demands are not commercially available. This paper provides insight into experiences with the Ada programming support environment on the first major Ada simulator project at Link. The paper discusses difficulties, lessons learned, and solutions. Our approach at Link was the result of a strong customer demand for improved software maintainability. This perspective strongly influenced all of our software-related decisions. Included in this paper are discussions of issues relating to managing Ada libraries on a large project, testing Ada software on a large project, and the need for a real-time architecture model to guide software engineers.
An Efficient Algorithm for Minimizing Real-Time Transition Systems
Authors: Mihalis Yannakakis, David Lee
Venue: Formal Methods in System Design (1997)

We address the problem of performing simultaneously reachability analysis and minimization of real-time transition systems represented by timed automata, i.e., automata extended with a finite set of clock variables. The transitions of the automaton may depend on the values of the clocks and may reset some of the clocks. An efficient algorithm is presented for minimizing a system with respect to a given initial partition that respects the enabling conditions of the transitions of the timed automaton. Our algorithm generates the portion of the minimized system that is reachable from a given initial configuration in time polynomial in the input and the size of the minimal reachable system.
On the Correctness of Inside-Out Routing Algorithm
Authors: M. K. Kim, H. Yoon, S. R. Maeng
Venue: IEEE Transactions on Computers (1997)

Recently, a new routing algorithm called inside-out routing algorithm was proposed for routing an arbitrary permutation in the omega-based 2log2N stage networks. This paper discusses the problems of the inside-out routing algorithm and shows that the suggested condition for proper routing in the omega-omega network is insufficient. An extended necessary and sufficient condition for proper routing in the omega-omega network is also suggested. However, it is unknown if any permutation can be successfully routed by a heuristic algorithm which follows the condition. Thus, the rearrangeability of the omega-omega network still remains an open problem.