ppxscal/embedding_network huggingface dataset:
A two moments RC delay metric for performance optimization
Authors: C. J. Alpert, A. Devgan, C. Kashyap
Venue: Proceedings of the 2000 international conference on Computer-aided design (2001)

For performance optimization tasks such as floorplanning, placement, buffer insertion, wire sizing, and global routing, the Elmore RC delay metric [3] remains popular due to its simple closed form expression, fast computation speed, and fidelity with respect to simulation. More accurate delay computation methods are typically either CPU intensive or difficult to implement. To bridge this gap between accuracy and simplicity, we propose the D2M RC delay metric, which is virtually as simple and fast as the Elmore metric but is bounded above by the Elmore delay, yet it rarely is more than a few percent below the actual delay. Consequently, the metric behaves like the Elmore metric in that it generally overestimates delay, but with consistently less error. Further, the metric is extremely accurate at the far end of RC lines.
A Fourier series method for the numerical solution of a class of parabolic partial differential equations
Authors: C. V. D. Forrington
Venue: Communications of the ACM (1964)

A Fourier series method is described which, when applied to a certain class of parabolic partial differential equations, reduces the problem to a system of ordinary differential equations. An application is given for which the method shows a considerable advantage over conventional finite difference methods.
Computing polynomial resultants: Bezout's determinant vs. Collins' reduced P.R.S. algorithm
Authors: S. Y. Ku, R. J. Adler
Venue: Communications of the ACM (1969)

Algorithms for computing the resultant of two polynomials in several variables, a key repetitive step of computation in solving systems of polynomial equations by elimination, are studied. Determining the best algorithm for computer implementation depends upon the extent to which extraneous factors are introduced, the extent of propagation of errors caused by truncation of real coeffcients, memory requirements, and computing speed. Preliminary considerations narrow the choice of the best algorithm to Bezout's determinant and Collins' reduced polynomial remainder sequence (p.r.s.) algorithm. Detailed tests performed on sample problems conclusively show that Bezout's determinant is superior in all respects except for univariate polynomials, in which case Collins' reduced p.r.s. algorithm is somewhat faster. In particular Bezout's determinant proves to be strikingly superior in numerical accuracy, displaying excellent stability with regard to round-off errors. Results of tests are reported in detail.
Evaluating topic-driven web crawlers
Authors: Filippo Menczer, Gautam Pant, Padmini Srinivasan, Miguel E. Ruiz
Venue: Proceedings of the 24th annual international ACM SIGIR conference on Research and development in information retrieval (2001)

Due to limited bandwidth, storage, and computational resources, and to the dynamic nature of the Web, search engines cannot index every Web page, and even the covered portion of the Web cannot be monitored continuously for changes. Therefore it is essential to develop effective crawling strategies to prioritize the pages to be indexed. The issue is even more important for topic-specific search engines, where crawlers must make additional decisions based on the relevance of visited pages. However, it is difficult to evaluate alternative crawling strategies because relevant sets are unknown and the search space is changing. We propose three different methods to evaluate crawling strategies. We apply the proposed metrics to compare three topic-driven crawling algorithms based on similarity ranking, link analysis, and adaptive agents.
On the sorting-complexity of suffix tree construction
Authors: Martin Farach-Colton, Paolo Ferragina, S. Muthukrishnan
Venue: Journal of the ACM (JACM) (2000)

The suffix tree of a string is the fundamental data structure of combinatorial pattern matching. We present a recursive technique for building suffix trees that yields optimal algorithms in different computational models. Sorting is an inherent bottleneck in building suffix trees and our algorithms match the sorting lower bound. Specifically, we present the following results. (1) Weiner [1973], who introduced the data structure, gave an optimal 0(n)-time algorithm for building the suffix tree of an n-character string drawn from a constant-size alphabet. In the comparison model, there is a trivial &Ogr;(n log n)-time lower bound based on sorting, and Weiner's algorithm matches this bound. For integer alphabets, the fastest known algorithm is the O(n log n)time comparison-based algorithm, but no super-linear lower bound is known. Closing this gap is the main open question in stringology. We settle this open problem by giving a linear time reduction to sorting for building suffix trees. Since sorting is a lower-bound for building suffix trees, this algorithm is time-optimal in every alphabet mode. In particular, for an alphabet consisting of integers in a polynomial range we get the first known linear-time algorithm. (2) All previously known algorithms for building suffix trees exhibit a marked absence of locality of reference, and thus they tend to elicit many page faults (I/Os) when indexing very long strings. They are therefore unsuitable for building suffix trees in secondary storage devices, where I/Os dominate the overall computational cost. We give a linear-I/O reduction to sorting for suffix tree construction. Since sorting is a trivial I/O-lower bound for building suffix trees, our algorithm is I/O-optimal.
Selected definitions
Authors: W. Barkley Fritz
Venue: Communications of the ACM (1963)

A selection of the definitions prepared by the ACM Standards Committee's Subcommittee on Programming Terminology is presented for review by the ACM membership.
On the present and future of scientific computation
Authors: John R. Rice
Venue: Communications of the ACM (1972)

A pessimistic forecast is given of what can be expected to happen in the application of computers to the physical sciences.
A 1-V Class-AB Translinear Integrator for Filter Applications
Authors: Paul J. Poort, Wouter A. Serdijn, Jan Mulder, Albert C. van der Woerd, Arthur H. M. van Roermund
Venue: Analog Integrated Circuits and Signal Processing (1999)

In this paper, the design and measurements of a 1-volt class-AB instantaneous companding translinear integrator are presented. The use of instantaneous companding and class-AB operation gives an improvement of the dynamic range and a reduction of the power consumption. The proposed circuit uses only bipolar transistors and one capacitor and is, therefore, very well suited for integrated implementation. Its unity-gain frequency can easily be controlled by a current. Simulations and measurements of a semicustom realization, to be applied in a hearing instrument, confirm correct operation of the designed circuit. The translinear integrator operates from a single supply voltage down to 0.95 V. The current consumption is less than 1.9 &mu;A for an input current of 180 nA (p). The dynamic range is better than 73 dB over a bandwidth of 8 kHz.
Conversion, reconversion and comparison techniques in variable-length sorting
Authors: David J. Waks
Venue: Communications of the ACM (1963)

The logic is described for converting highly variable input records into a format that can be easily and efficiently processed by a sorting program.1 The internal record formats are discussed in relation to (1) their conversion from input formats, (2) their reconversion to output formats, and (3) comparison techniques between internal formats.
Database abstractions: aggregation
Authors: John Miles Smith, Diane C. P. Smith
Venue: Communications of the ACM (1977)

Aggregation is introduced as an abstraction which is important in conceptualizing the real world. Aggregation transforms a relationship between objects into a higher-level object. A new data type, called aggregate, is developed which, under certain criteria of &ldquo;well-definedness,&rdquo; specifies aggregation abstractions. Relational databases defined as collections of aggregates are structured as a hierarchy of n-ary relations. To maintain well-definedness, update operations on such databases must preserve two invariants. Well-defined relations are distinct from relations in third normal form. It is shown that these notions are complementary and both are important in database design. A top-down methodology for database design is described which separates decisions concerning aggregate structure from decisions concerning key identification. It is suggested that aggregate types, and other types which support real-world abstractions without introducing implementation detail, should be incorporated into programming languages.
Dynamic document processing
Authors: Gerard Salton
Venue: Communications of the ACM (1972)

The current role of computers in automatic document processing is briefly outlined, and some reasons are given why the early promise of library automation and of the mechanization of documentation processes has not been fulfilled. A new dynamic document environment is then outlined in which clustered files are searched and information is retrieved following an interactive user-controlled search process. Methods are described for an automatic query modification based on user needs, and for a continuous reorganization of the stored information as a function of earlier file processing and of normal collection growth. The proposed procedures provide powerful tools for information retrieval and for the control of dynamic library collections in which new items are continually added and ones are retired.
Combining tasking and transactions, part II: open multithreaded transactions
Authors: Jörg Kienzle, Alexander Romanovsky
Venue: ACM SIGAda Ada Letters (2001)

This position paper is a follow-up paper of [1], presented at the last IRTAW workshop. The paper describes a model for providing transaction support for concurrent programming languages such as Ada 95. In order to achieve smooth integration, the use of the concurrency features provided by the Ada language should not be restricted inside a transaction. A transaction model that meets this requirement is presented. Tasks inside such a transaction may spawn new tasks, but also external tasks are allowed to join an ongoing transaction. A blocking commit protocol ensures that no task leaves the transaction before its outcome has been determined. Exceptions are used to inform all participants in case a transaction aborts. Possible interfaces for the Ada programmer are discussed.
The cyclic order property of vertices as an aid in scene analysis
Authors: R. Shapira, H. Freeman
Venue: Communications of the ACM (1979)

A cyclic-order property is defined for bodies bounded by smooth-curved faces. The property is shown to be useful for analyzing pictures of such bodies, particularly when the line data extracted from the pictures are imperfect. This property augments previously known grammatical rules that determine the existence of three-dimensional bodies corresponding to given two-dimensional line-structure data.
Dynamic reorganization of decision-making groups
Authors: K. S. Barber, C. E. Martin
Venue: Proceedings of the fifth international conference on Autonomous agents (2001)

Agents in a multi- agent system must coordinate to achieve their goals, in general. Establishing an organizational structure that specifies how agents in the system should work together helps multi- agent systems achieve effective coordination. Among other things, an organizational structure specifies agent decisionmaking frameworks. A decision- making framework identifies the locus of decision- making control for a given goal and the authority of decision- makers to assign subtasks in order to achieve that goal. Agents may participate in different decision- making frameworks for each goal they pursue. Agents who implement the capability of Adaptive Decision- Making Frameworks (ADMF) are able to dynamically modify their decision- making frameworks at run- time to best meet the needs of their current situation. Through ADMF, agents are able to reorganize decision- making groups by dynamically changing (1) who makes the decisions for a particular goal and (2) who must carry out these decisions. This paper presents experiments exploring the following hypothesis: Multi- agent systems that implement ADMF can perform better and more robustly across run- time changes in situation than systems that maintain static decision- making frameworks. Experimental results show that no one decision- making framework performs best across various situations that may be faced at run- time. Further experiments show that the implementation of ADMF in multi- agent systems can improve system performance across changing situations. These experimental results clearly motivate the implementation of Adaptive Decision- Making Frameworks in multi- agent systems.
Scalable parallel algorithms for interactive visualization of curved surfaces
Authors: Subodh Kumar, Chun-Fa Chang, Dinesh Manocha
Venue: Proceedings of the 1996 ACM/IEEE conference on Supercomputing (CDROM) (1996)

We present efficient parallel algorithms for interactive display of higher order surfaces on current graphics systems. At each frame, these algorithms approximate the surface by polygons and rasterize them over the graphics pipeline. The time for polygon generation for each surface primitive varies between successive frames and we address issues in distributing the load across processors for different environments. This includes algorithms to statically distribute the primitives to reduce dynamic load imbalance as well a distributed wait-free algorithm for machines on which re-distribution is efficient, e.g. shared memory machine. These algorithms have been implemented on different graphics systems and applied to interactive display of trimmed spline models. In practice, we are able to obtain almost linear speed-ups (as a function of number of processors). Moreover, the distributed wait-free algorithm is faster by 25-30% as compared to static and dynamic schemes.
Computer-Aided complexity classification of combinational problems
Authors: B. J. Lageweg, J. K. Lenstra, E. L. Lawler, A. H. G. Rinnooy Kan
Venue: Communications of the ACM (1982)

We describe a computer program that has been used to maintain a record of the known complexity results for a class of 4536 machine scheduling problems. The input of the program consists of a listing of known &ldquo;easy&rdquo; problems and a listing of known &ldquo;hard&rdquo; problems. The program employs the structure of the problem class to determine the implications of these results. The output provides a listing of essential results in the form of maximal easy and minimal hard problems as well as listings of minimal and maximal open problems, which are helpful in indicating the direction of future research. The application of the program to a restricted class of 120 single-machine problems is demonstrated. Possible refinements and extensions to other research areas are suggested. It is also shown that the problem of determining the minimum number of results needed to resolve the status of all remaining open problems in a complexity classification such as ours is itself a hard problem.
Implementation of a portable software DSM in Java
Authors: Yukihiko Sohda, Hidemoto Nakada, Satoshi Matsuoka
Venue: Proceedings of the 2001 joint ACM-ISCOPE conference on Java Grande (2001)

Rapid commoditization of advanced hardware and progress of networking technology is now making wide area high-performance computing a.k.a. the 'Grid' Computing a reality. Since a Grid will consist of vastly heterogeneous sets of compute nodes, especially commodity clusters, some have articulated the use of Java as a suitable technology to satisfy portability across different machines. Since Java's natural model parallelism is shared memory multithreading, one will have to support distributed shared memory (DSM) in a portable manner; however, none of the previous work on implementing Java on DSM has been a portable solution. Instead, we propose a software architecture whose goal is to achieve portability of DSM implementations across different commodity clustering platforms, while restricting the programming model somewhat, and implemented a prototype system, JDSM. Benchmark results show that the current implementation on Java incurs increased memory coherency maintenance cost compared to C-based DSMs, thus limiting scalability to some degree, and we are currently working on a solution to alleviate this cost.
Comments on &ldquo;a continued operation notation&rdquo;
Authors: M. P. Barnett, J. M. Gerard, A. W. Sambles
Venue: Communications of the ACM (1964)

This note is intended to clarify and correct several points in a recent paper describing some notations for symbol manipulation by M. P. Barnett [Comm. ACM 6(August, 1963)].
NEATER2: a PL/I source statement reformatter
Authors: Kenneth Conrow, Ronald G. Smith
Venue: Communications of the ACM (1970)

NEATER2 accepts a PL/I source program and operates on it to produce a reformatted version. When in the LOGICAL mode, NEATER2 indicates the logical structure of the source program in the indentation pattern of its output. Logic errors discovered through NEATER2 logical analysis are discovered much more economically than is possible through compilation and trial runs. A number of options are available to give the user full control over the output format and to maximize the utility of NEATER2 as an aid during the early stages of development of a PL/I source deck. One option, USAGE, causes NEATER2 to insert into each logical unit of coding a statement which will cause the number of times each one is executed to be recorded during execution. This feature is expected to provide a major aid in optimization of PL/I programs.
A program to teach programming
Authors: Robert R. Fenichel, Joseph Weizenbaum, Jerome C. Yochelson
Venue: Communications of the ACM (1970)

The TEACH system was developed at MIT to ease the cost and improve the results of elementary instruction in programming. To the student, TEACH offers loosely guided experience with a conversational language which was designed with teaching in mind. Faculty involvement is minimal. A term of experience with TEACH is discussed. Pedagogically, the system appears to be successful; straighforward reimplementation will make it economically successful as well. Similar programs of profound tutorial skill will appear only as the results of extended research. The outlines of this research are beginning to become clear.
Lower Bounds for Two-Level Additive Schwarz Preconditioners with Small Overlap
Authors: Susanne C. Brenner
Venue: SIAM Journal on Scientific Computing (1999)

Lower bounds for the condition numbers of the preconditioned systems are obtained for two-level additive Schwarz preconditioners. They show that the known upper bounds for both second order and fourth order problems are sharp in the case of a small overlap.
A language for treating geometric patterns in a two-dimensional space
Authors: G. Bracchi, D. Ferrari
Venue: Communications of the ACM (1971)

In this paper CADEP, a problem-oriented language for positioning geometric patterns in a two-dimensional space, is presented. Although the language has been specifically designed for the automatic generation of integrated circuit masks, it turns out to be well suited also for such other placement problems as architecture design, urban planning, logical and block diagram representation. The design criteria, the structure, and the specific features of CADEP are illustrated.
Correction to &ldquo;logical&rdquo; arithmetric on computers with two's complement binary arithmetic
Authors: John R. Ehrman
Venue: Communications of the ACM (1970)

In reference [1] algorithms for performing arithmetic with unsigned two's complement operands were described. The scheme for division was implemented in a set of multiple-precision floating-point arithmetic routines [2]. User experience with those routines showed that there is one case where the algorithm fails [3]. We give here a modification to the algorithm which eliminates the error condition. Equations are numbered beginning with (20), so that we may refer to equations in the original paper as well.
Linux Prophet
Authors: Glen Otero
Venue: Linux Journal (2001)

Linux consulting is not really about Linux.
The collaborative cube puzzle: a comparison of virtual and real environments
Authors: Josef Wideström, Ann-Sofie Axelsson, Ralph Schroeder, Alexander Nilsson, Ilona Heldal, Åsa Abelin
Venue: Proceedings of the third international conference on Collaborative virtual environments (2000)

In this study we compared collaboration on a puzzle-solving task carried out by two persons in a virtual and a real environment. The task, putting together a cube consisting of different coloured blocks in a 'Rubiks' cubetype puzzle, was performed both in a shared virtual environment (VE) setting, using a Cave-type virtual reality (VR) system networked with a desktop VR system, and with cardboard coloured blocks in an equivalent real setting. The aims of the study were to investigate collaboration, leadership and performance in the two settings. We found that the participants contributed unequally to the task in the VE, and also differences in collaboration between the virtual and the real setting.
Visual information foraging in a focus + context visualization
Authors: Peter Pirolli, Stuart K. Card, Mija M. Van Der Wege
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (2001)

Eye tracking studies of the Hyperbolic Tree browser [10] suggest that visual search in focus+context displays is highly affected by information scent (i.e., local cues, such as text summaries, used to assess and navigate toward distal information sources). When users detected a strong information scent, they were able to reach their goal faster with the Hyperbolic Tree browser than with a conventional browser. When users detected a weak scent or no scent, users exhibited less efficient search of areas with a high density of visual items. In order to interpret these results we present an integration of the CODE Theory of Visual Attention (CTVA) with information foraging theory. Development of the CTVA-foraging theory could lead to deeper analysis of interaction with visual displays of content, such as the World Wide Web or information visualizations.
Design, implementation, and evaluation of programmable handoff in mobile networks
Authors: Michael E. Kounavis, Andrew T. Campbell, Gen Ito, Giuseppe Bianchi
Venue: Mobile Networks and Applications (2001)

We describe the design, implementation and evaluation of a programmable architecture for profiling, composing and deploying handoff services. We argue that future wireless access networks should be built on a foundation of open programmable networking allowing for the dynamic deployment of new mobile and wireless services. Customizing handoff control and mobility management in this manner calls for advances in software and networking technologies in order to respond to specific radio, mobility and service quality requirements of future wireless Internet service providers. Two new handoff services are deployed using programmable mobile networking techniques. First, we describe a &ldquo;multi-handoff&rdquo; access network service, which is capable of simultaneously supporting multiple styles of handoff control over the same physical wireless infrastructure. Second, we discuss a &ldquo;reflective handoff&rdquo; service, which allows programmable mobile devices to freely roam between heterogeneous wireless access networks that support different signaling systems. Evaluation results indicate that programmable handoff architectures are capable of scaling to support a large number of mobile devices while achieving similar performance to that of native signaling systems.