ppxscal/embedding_network huggingface dataset:
A Branch Cut Algorithm for the Asymmetric Traveling Salesman Problem with Precedence Constraints
Authors: Norbert Ascheuer, Michael Jünger, Gerhard Reinelt
Venue: Computational Optimization and Applications (2000)

In this article we consider a variant of the classical asymmetric traveling salesman problem (ATSP), namely the ATSP in which precedence constraints require that certain nodes must precede certain other nodes in any feasible directed tour. This problem occurs as a basic model in scheduling and routing and has a wide range of applications varying from helicopter routing (Timlin, Master's Thesis, Department of Combinatorics and Optimization, University of Waterloo, 1989), sequencing in flexible manufacturing (Ascheuer et al., Integer Programming and Combinatorial Optimization, University of Waterloo, Waterloo, 1990, pp. 19&ndash;28&semi; Idem., SIAM Journal on Optimization, vol. 3, pp. 25&ndash;42, 1993), to stacker crane routing in an automatic storage system (Ascheuer, Ph.D. Thesis, Tech. Univ. Berlin, 1995). We give an integer programming model and summarize known classes of valid inequalities. We describe in detail the implementation of a branch cut-algorithm and give computational results on real-world instances and benchmark problems from TSPLIB. The results we achieve indicate that our implementation outperforms other implementations found in the literature. Real world instances with more than 200 nodes can be solved to optimality within a few minutes of CPU-time. As a side product we obtain a branch cut-algorithm for the ATSP. All instances in TSPLIB can be solved to optimality in a reasonable amount of computation time.
Satchel: providing access to any document, any time, anywhere
Authors: Mik Lamming, Marge Eldridge, Mike Flynn, Chris Jones, David Pendlebury
Venue: ACM Transactions on Computer-Human Interaction (TOCHI) (2000)

Current solutions for providing access to electronic documents while away from the office do not meet the special needs of mobile document workers. We describe &rdquo;Satchel,&ldquo; a system that is designed specifically to support the distinctive features of mobile document work. Satchel is designed to meet the following five high-level design goals (1) easy access to document services; (2) timely document access; (3) streamlined user interface; (4) ubiquity; and (5)compliance with security policies. Our current prototype uses a Nokia 9000 Communicator as the mobile device; it communicates to the rest of the Satchel system using wireless communications, both infrared and radio. A fundamental Satchel concept is the use of tokens, or small secure references, to represent documents on the mobile device. The mobile client only transmits small tokens over te wireless channels, leaving the wired network to transmit the contents of documents when, and only when, they are required. Another fundmental Satchel concept is the highly speclized and context-sensitive user interface on the mobile device. The user's interactions ae streamlined because of this specialization and though the use of contextual information gained by uing infrared communications. We report the results of a trial of Satchel that was carried out within our own company, and discuss how well Satchel met our design goals. We call Satchel a &rdquo;document appliance&rdquo; because it provides a streamlined soultion to the problem of remote document access&mdash;it aims to support only a limited set of activities, but supports them very well.
Integrating superscalar processor components to implement register caching
Authors: Matthew Postiff, David Greene, Steven Raasch, Trevor Mudge
Venue: Proceedings of the 15th international conference on Supercomputing (2001)

A large logical register file is important to allow effective compiler transformations or to provide a windowed space of registers to allow fast function calls. Unfortunately, a large logical register file can be slow, particularly in the context of a wide-issue processor which requires an even larger physical register file, and many read and write ports. Previous work has suggested that a register cache can be used to address this problem. This paper proposes a new register caching mechanism in which a number of good features from previous approaches are combined with existing out-of-order processor hardware to implement a register cache for a large logical register file. It does so by separating the logical register file from the physical register file and using a modified form of register renaming to make the cache easy to implement. The physical register file in this configuration contains fewer entries than the logical register file and is designed so that the physical register file acts as a cache for the logical register file, which is the backing store. The tag information in this caching technique is kept in the register alias table and the physical register file. It is found that the caching mechanism improves IPC up to 20% over an un-cached large logical register file and has performance near to that of a logical register file that is both large and fast.
A fast algorithm for copying list structures
Authors: Douglas W. Clark
Venue: Communications of the ACM (1978)

An algorithm is presented for copying an arbitrarily linked list structure into a block of contiguous storage locations without destroying the original list. Apart from a fixed number of program variables, no auxillary storage, such as a stack, is used. The algorithm needs no mark bits and operates in linear time. It is shown to be significantly faster than Fisher's algorithm, the fastest previous linear-time algorithm for the same problem. Its speed comes mainly from its efficient list-traversal technique, which folds the processing stack into the structure being built, and from its classification of list cells into nine types, which enables processing operations to be optimized for each type.
The use of quadratic residue research
Authors: Charles E. Radke
Venue: Communications of the ACM (1970)

Some of the problems of simulating discrete event systems, particularly computer systems, on a conventional digital computer are dealt with. The systems are assumed to be described as a network of interconnected sequential processes. Briefly reviewed are the common techniques used to handle such simulations when simultaneous events do not occur, can be ignored, or can be handled by simple priority rules. Following this, the problem of dealing with simultaneous events in separate processes is introduced. An abstraction of this problem is developed which admits solution for a majority of commonly encountered problems. The technique will either find a method of simulating the parallel events or report that none can be found. In some of the latter cases it is shown to be possible to find a solution by extending the information available to the solution technique, but in many cases the technique becomes computationally unfeasible when the additional information is provided.
SMC: a symmetry-based model checker for verification of safety and liveness properties
Authors: A. Prasad Sistla, Viktor Gyuris, E. Allen Emerson
Venue: ACM Transactions on Software Engineering and Methodology (TOSEM) (2000)

The article presents the SMC system. SMC can be used for checking safety and liveness properties of concurrent programs under different fairness assumptions. It is based on explicit state enumeration. It combats the state explosion by exploiting symmetries of the input concurrent program, usually present in the form of identical processes, in two different ways. Firstly, it reduces the number of explored states by identifying those states that are equivalent under the symmetries of the system; this is called process symmetry. Secondly, it reduces the number of edges explored from each state, in0 the reduced state graph, by exploiting the symmetry of a single state; this is called state symmetry. SMC works in an on-the-fly manner; it constructs the reduced state graph as and when it is needed. This method facilitates early termination, speeds up model checking, and reduces memory requirements. We employed SMC to check the correctness of, among other standard examples, the Link Layer part of the IEEE Standard 1394 &ldquo;Firewire&rdquo; high-speed serial bus protocol. SMC found deadlocks in the protocol. SMC was also to check certain liveness properties. A report on the case study is included in the article.
Time Stamp Algorithms for Runtime Parallelization of DOACROSS Loops with Dynamic Dependences
Authors: Cheng-Zhong Xu, Vipin Chaudhary
Venue: IEEE Transactions on Parallel and Distributed Systems (2001)

This paper presents a time stamp algorithm for runtime parallelization of general DOACROSS loops that have indirect access patterns. The algorithm follows the INSPECTOR/EXECUTOR scheme and exploits parallelism at a fine-grained memory reference level. It features a parallel inspector and improves upon previous algorithms of the same generality by exploiting parallelism among consecutive reads of the same memory element. Two variants of the algorithm are considered: One allows partially concurrent reads (PCR) and the other allows fully concurrent reads (FCR). Analyses of their time complexities derive a necessary condition with respect to the iteration workload for runtime parallelization. Experimental results for a Gaussian elimination loop, as well as an extensive set of synthetic loops on a 12-way SMP server, show that the time stamp algorithms outperform iteration-level parallelization techniques in most test cases and gain speedups over sequential execution for loops that have heavy iteration workloads. The PCR algorithm performs best because it makes a better trade-off between maximizing the parallelism and minimizing the analysis overhead. For loops with light or unknown iteration loads, an alternative speculative runtime parallelization technique is preferred.
Bent Functions, Partial Difference Sets, and Quasi-FrobeniusLocal Rings
Authors: Xiang-Dong Hou
Venue: Designs, Codes and Cryptography (2000)

Bent functions and partial difference sets have been constructed from finite principal ideal local rings. In this paper, the constructions are generalized to finite quasi-Frobenius local rings. Let R be a finite quasi-Frobenius local ring with maximal ideal M. Bent functions and certain partial difference sets on M\times M are extended to R\times R.
An efficient, incremental, automatic garbage collector
Authors: L. Peter Deutsch, Daniel G. Bobrow
Venue: Communications of the ACM (1976)

This paper describes a new way of solving the storage reclamation problem for a system such as Lisp that allocates storage automatically from a heap, and does not require the programmer to give any indication that particular items are no longer useful or accessible. A reference count scheme for reclaiming non-self-referential structures, and a linearizing, compacting, copying scheme to reorganize all storage at the users discretion are proposed. The algorithms are designed to work well in systems which use multiple levels of storage, and large virtual address space. They depend on the fact that most cells are referenced exactly once, and that reference counts need only be accurate when storage is about to be reclaimed. A transaction file stores changes to reference counts, and a multiple reference table stores the count for items which are referenced more than once.
Optical Flow Constraints on Deformable Models with Applications to Face Tracking
Authors: Douglas Decarlo, Dimitris Metaxas
Venue: International Journal of Computer Vision (2000)

Optical flow provides a constraint on the motion of a deformable model. We derive and solve a dynamic system incorporating flow as a hard constraint, producing a model-based least-squares optical flow solution. Our solution also ensures the constraint remains satisfied when combined with edge information, which helps combat tracking error accumulation. Constraint enforcement can be relaxed using a Kalman filter, which permits controlled constraint violations based on the noise present in the optical flow information, and enables optical flow and edge information to be combined more robustly and efficiently. We apply this framework to the estimation of face shape and motion using a 3D deformable face model. This model uses a small number of parameters to describe a rich variety of face shapes and facial expressions. We present experiments in extracting the shape and motion of a face from image sequences which validate the accuracy of the method. They also demonstrate that our treatment of optical flow as a hard constraint, as well as our use of a Kalman filter to reconcile these constraints with the uncertainty in the optical flow, are vital for improving the performance of our system.
Protecting privacy using the decentralized label model
Authors: Andrew C. Myers, Barbara Liskov
Venue: ACM Transactions on Software Engineering and Methodology (TOSEM) (2000)

Stronger protection is needed for the confidentiality and integrity of data, because programs containing untrusted code are the rule rather than the exception. Information flow control allows the enforcement of end-to-end security policies, but has been difficult to put into practice. This article describes the decentralized label model, a new label model for control of information flow in systems with mutual distrust and decentralized authority. The model improves on existing multilevel security models by allowing users to declassify information in a decentralized way, and by improving support for fine-grained data sharing. It supports static program analysis of information flow, so that programs can be certified to permit only acceptable information flows, while largely avoiding the overhead of run-time checking. The article introduces the language Jif, an extension to Java that provides static checking of information flow using the decentralized label model.
Practical Structure and Motion from Stereo When Motion is Unconstrained
Authors: Nicholas Molton, Michael Brady
Venue: International Journal of Computer Vision (2000)

This paper describes a system which robustly estimates motion, and the 3D structure of a rigid environment, as a stereo vision platform moves through it. The system can cope with any camera motion, and any scene structure and is successful even in the presence of large jumps in camera position between the capture of successive image pairs, and when point matching is ambiguous. The system was developed to provide robust obstacle avoidance for a partially sighted person.The process described attempts to maximise use of the abundant information present in a stereo sequence. Key features include the use of multiple stereo match hypotheses, efficient motion computation from three images, and the use of this motion to ensure reliable matching, and to eliminate multiple stereo matches. Points are reconstructed in 3D space and tracked in a static coordinate frame with a Kalman Filter.This results in good 3D scene reconstructions. Structure which is impossible to match with certainty is absent, rather than being incorrectly reconstructed. As a result, the system is appropriate for obstacle detection. The results of processing some indoor and outdoor scenes, are given in the paper, and practical issues are highlighted throughout.
Global internet roaming with ROAMIP
Authors: Zoltán R. Turányi, Csanád Szabó, Eszter Kail
Venue: ACM SIGMOBILE Mobile Computing and Communications Review (2000)

Reachability and session continuity represent two distinct services that global mobility protocols should provide. Reachability is the possibility for Internet hosts to initiate sessions to mobile users. Session continuity refers to mechanisms that ensure that active transport or application layer sessions are not broken due to mobility. We present ROAMIP, a global mobility architecture that uses application layer solutions for global reachability and reuses transparent Mobile IP tunnelling mechanisms to ensure session continuity. ROAMIP eliminates long triangular routes, yet it is compatible with mobility unaware correspondent hosts. It is applicable to IPv6 as well as IPv4 networks. The ROAMIP architecture naturally lends itself to easy, gradual deployment and can reuse existing Mobile IP or SIP message formats. We conclude the paper by showing example traces from an experimental implementation.
Writing a textbook: walking the gauntlet
Authors: Nell Dale, Rick Mercer, Elliot Koffman, Walter Savitch
Venue: ACM SIGCSE Bulletin (2001)

Writing my first textbook was an eye-opening experience. I had to dig deep. I had ideas I was excited about and found others that were excited about them as well. I also found strong opposition to my approach, which was difficult for publishers to evaluate. My experience raised a number of questions that I have outlined below. These questions range from personnel motivation to future trends in computing. I have gathered a panel of respected authors. I have asked each to respond to some of these questions. Time will also be available for the audience to ask questions and share their own experiences.
Special message from the presidents of ACM and the IEEE Computer Society: where do parallel lines meet? or the common goals of ACM and the IEEE-CS
Authors: David H. Brandin, Oscar N. Garcia
Venue: Communications of the ACM (1983)

In the changing computer world of multiple opportunities, the greatest difficulty lies in deciding which of the many possible dreams to strive for, what goals to set. The IEEE Computer Society and the Association for Computing Machinery, the two largest and fastest growing professional organizations in the computer field, have come to share more or less independently, a great number of common objectives. The distinction between the two societies is no longer clear. What might once have been a clear separation of interest and programs is now a continuum with most of our activities intertwined.
Techniques for automatic tolerance control in linear programming
Authors: R. J. Clasen
Venue: Communications of the ACM (1966)

In this technical note, the numerical steps for the simplex method of linear programming are reviewed and the tolerances needed in the numerical procedure are defined. Objective criteria are given for accomplishing the numerical steps of the method and the calculation of necessary tolerances.
Semantic based image retrieval: a probabilistic approach
Authors: Ben Bradshaw
Venue: Proceedings of the eighth ACM international conference on Multimedia (2000)

This paper describes an approach to image retrieval based on the underlying semantics of images. To extract these semantics a hierarchical, probabilistic approach is proposed. The labels that are extracted in this case are man-made, natural, inside and outside. The hierarchical framework combines class likelihood probability estimates across a number of levels to form a posterior estimate of the probability of class membership. Unlike previous work in this field, the proposed algorithm can determine probabilities at any point in the scene and only a small number of images are required to train the system. To illustrate the potential of such an approach a prototype image retrieval system has been developed, initial results from this system are given in this paper.
RECOL&mdash;a retrieval command language
Authors: W. D. Climenson
Venue: Communications of the ACM (1963)

An interrogation scheme is described for the retrieval and manipulation of data file records. The language of the interrogation scheme allows for selecting file records with the use of logical condition statements, defining record classes, associating file records, editing printed output, and summarizing the results of the above operations. Some examples of a typical file application and the more significant features of a particular machine implementation are given.
NestStep: Nested Parallelism and Virtual Shared Memory for the BSP Model
Authors: Christoph W. Keßler
Venue: The Journal of Supercomputing (2000)

NestStep is a parallel programming language for the BSP (bulk&ndash;synchronous&ndash;parallel) model of parallel computation.Extending the classical BSP model, NestStep supports dynamically nested parallelism by nesting of supersteps and a hierarchical processor group concept. Furthermore, NestStep adds a virtual shared memory realization in software, where memory consistency is relaxed to superstep boundaries. Distribution of shared arrays is also supported.A prototype for a subset of NestStep has been implemented based on Java as sequential basis language. The prototype implementation is targeted to a set of Java Virtual Machines coupled by Java socket communication to a virtual parallel computer.
Occupational stress, attitudes, and health problems in the information systems professional
Authors: John M. Ivancevich, H. Albert Napier, James C. Wetherbe
Venue: Communications of the ACM (1983)

This study examines occupational stress among information systems personnel. A self-report stress and health behavior instrument was completed by 580 respondents in 18 large corporations in the midwestern and southwestern sections of the United States. The data indicate that various job factors are perceived as stressful by respondents. However, the stress levels reported by respondents are not as excessive as have been found in studies of other occupational groups.
Linking live and replay scenes in broadcasted sports video
Authors: Noboru Babaguchi, Yoshihiko Kawai, Yukinobu Yasugi, Tadahiro Kitahashi
Venue: Proceedings of the 2000 ACM workshops on Multimedia (2000)

Content based video organization requires to understand semantical relationships such as identity and similarity between video segments. In particular, it is of great interest to identify scenes of the same event which may differ in their appearances. For broadcasted sports video, such scenes correspond to live and replay scenes that appear at different temporal positions. In this paper, we propose a method of linking up live and replay scenes by focusing on the domain knowledge about producing TV programs of sports: most of the replay scenes are sandwiched in between specific digital video effects. The replay scenes are linked with live scenes when the game is in play based on salient image features. We clarify the effectiveness of our method through fundamental experiments for American football games.
Cooperative multi-agent intelligent field terminals
Authors: Juichi Kosakaya, Katsunori Yamaoka
Venue: Proceedings of the fifth international conference on Autonomous agents (2001)

We have developed a method for improving cooperation in complex systems that uses multi- agent (MA) intelligent field terminals (IFTs). The MA function evaluates the control conditions of the overall system and the conditions of the other IFTs. To shorten the turn- around time for data transfer among IFTs, the conflicts that occur when the data processed by different IFTs is inconsistent or irregular must be resolved autonomously. We thus incorporate a predictive agent in each IFT, and these agents cooperate to resolve the conflicts. Experimental results showed that this method not only provides adequate controls but also reduces the load on the network and the turn- around time when the number of IFTs is less than 30.
Parallel Algorithms to Evaluate Orthogonal Polynomial Series
Authors: Roberto Barrio
Venue: SIAM Journal on Scientific Computing (1999)

In this paper four parallel algorithms for the evaluation of finite series of orthogonal polynomials are introduced. The algorithms are based on the Forsythe and Clenshaw sequential algorithms. Several tests carried out on a Cray T3D are presented.