ppxscal/embedding_network huggingface dataset:
Network aware time management and event distribution
Authors: George F. Riley, Richard Fujimoto, Mostafa H. Ammar
Venue: Proceedings of the fourteenth workshop on Parallel and distributed simulation (2000)

In this paper we discuss new synchronization algorithms for Parallel and Distributed Discrete Event Simulations (PDES) which exploit the capabilities and behavior of the underlying communications network. Previous work in this areas has assumed the network to be a Black Box which provides a one-to-one, reliable and in-order message passing paradigm. In our work, we utilize the Broadcast capability of the ubiquitous Ethernet for synchronization computations, and both unreliable and reliable protocols for message passing, to achieve more efficient communications between the participating systems. We describe two new algorithms for computation of a distributed snapshot of global reduction operations on monotonically increasing values. The algorithms require O(N) messages (where N is the number of systems participating in the snapshot) in the normal case. We specifically target the use of this algorithm for distributed discrete event simulations to determine a global lower bound on time-stamp (LBTS), but expect the algorithm has applicability outside the simulation community.
Footprints: history-rich tools for information foraging
Authors: Alan Wexelblat, Pattie Maes
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

Inspired by Hill and Hollans original work [7], we have been developing a theory of interaction history and building tools to apply this theory to navigation in a complex information space. We have built a series of tools - map, paths, annota- tions and signposts - based on a physical-world navigation metaphor. These tools have been in use for over a year. Our user study involved a controlled browse task and showed that users were able to get the same amount of work done with significantly less effort.
Composite Schemes for Conservation Laws
Authors: Richard Liska, Burton Wendroff
Venue: SIAM Journal on Numerical Analysis (1998)

Global composition of several time steps of the two-step Lax--Wendroff scheme followed by a Lax--Friedrichs step seems to enhance the best features of both, although it is only first order accurate. We show this by means of some examples of one-dimensional shallow water flow over an obstacle. In two dimensions we present a new version of Lax--Friedrichs and an associated second order predictor-corrector method. Composition of these schemes is shown to be effective and efficient for some two-dimensional Riemann problems and for Noh's infinite strength cylindrical shock problem. We also show comparable results for composition of the predictor-corrector scheme with a modified second order accurate weighted essentially nonoscillatory (WENO) scheme. That composition is second order but is more efficient and has better symmetry properties than WENO alone. For scalar advection in two dimensions the optimal stability of the new predictor-corrector scheme is shown using computer algebra. We also show that the generalization of this scheme to three dimensions is unstable, but by using sampling we are able to show that the composites are suboptimally stable.
Revitalizing X.25 Networks
Authors: Michael J. Lopilato
Venue: International Journal of Network Management (1996)

How can PPP, which traditionally runs over asynchronous lines, be made to function over an X.25 network without adding to remote user expense or complexity? The answer can be found in this article, which describes the ACC SYSTEMS WANSERVER&trade;
The use of PC based VR in clinical medicine: the VREPAR projects
Authors: G. Riva, M. Bacchetta, M. Baruffi, E. Borgomainerio, C. Defrance, F. Gatti
Venue: Technology and Health Care (1999)

Virtual reality (VR) is an emerging technology that alters the way individuals interact with computers colon; a 3D computer-generated environment in which a person can move about and interact as if he actually was inside it. Given to the high computational power required to create virtual enviroments, these are usually developed on expensive high-end workstations. However, the significant advances in PC hardware that have been made over the last three years, are making PC-based VR a possible solution for clinical assessment and therapy. VREPAR - Virtual Reality Environments for Psychoneurophysiological Assessment and Rehabilitation - are two European Community funded projects (Telematics for health - HC 1053/HC 1055 - http colon;//www.psicologia.net) that are trying to develop a modular PC-based virtual reality system for the medical market. The paper describes the rationale of the developed modules and the preliminary results obtained.
Issues in calibrating effort estimation models
Authors: Petri Vesterinen
Venue: ACM SIGSOFT Software Engineering Notes (1999)

This paper discusses some important issues when calibrating, or developing effort estimation models for software projects. The author has developed and calibrated several effort estimation models within Nokia Corporation. The paper takes use of the experience gained in those situations.
A case study in root cause defect analysis
Authors: Marek Leszak, Dewayne E. Perry, Dieter Stoll
Venue: Proceedings of the 22nd international conference on Software engineering (2000)

There are three interdependent factors that drive our software development processes: interval, quality and cost. As market pressures continue to demand new features ever more rapidly, the challenge is to meet those demands while increasing, or at least not sacrificing, quality. One advantage of defect prevention as an upstream quality improvement practice is the beneficial effect it can have on interval: higher quality early in the process results in fewer defects to be found and repaired in the later parts of the process, thus causing an indirect interval reduction.We report a retrospective root cause defect analysis study of the defect Modification Requests (MRs) discovered while building, testing, and deploying a release of a transmission network element product. We subsequently introduced this analysis methodology into new development projects as an in-process measurement collection requirement for each major defect MR.We present the experimental design of our case study discussing the novel approach we have taken to defect and root cause classification and the mechanisms we have used for randomly selecting the MRs to analyze and collecting the analyses via a web interface. We then present the results of our analyses of the MRs and describe the defects and root causes that we found, and delineate the countermeasures created to either prevent those defects and their root causes or detect them at the earliest possible point in the development process.We conclude with lessons learned from the case study and resulting ongoing improvement activities.
QoS-aware resource management for distributed multimedia applications
Authors: Klara Nahrstedt, Hao-hua Chu, Srinivas Narayan
Venue: Journal of High Speed Networks (1998)

The ability of operating system and network infrastructure to provide end-to-end quality of service (QoS) guarantees in multimedia is a major acceptance factor for various distributed multimedia applications due to the temporal audio-visual and sensory information in these applications. Our constraints on the end-to-end guarantees are (1) QoS should be achieved on a general-purpose platform with a real-time extension support, and (2) QoS should be application-controllable. In order to achieve the users acceptance requirements and to satisfy our constraints on the multimedia systems, we need a QoS-compliant resource management which supports QoS negotiation, admission and reservation mechanisms in an integrated and accessible way. In this paper we present a new resource model and a time-variant QoS management, which are the major components of the QoS-compliant resource management. The resource model incorporates, the resource scheduler, and a new component, the resource broker, which provides negotiation, admission and reservation capabilities for sharing resources such as CPU, network or memory corresponding to requested QoS. The resource brokers are intermediary resource managers semi; when combined with the resource schedulers, they provide a more predictable and finer granularity control of resources to the applications during the end-to-end multimedia communication than what is available in current general-purpose networked systems. Furthermore, this paper presents the QoS-aware resource management model called QualMan, as a loadable middleware, its design, implementation, results, tradeoffs, and experiences. There are trade-offs when comparing our QualMan QoS-aware resource management in middleware and other QoS-supporting resource management solutions in kernel space. The advantage of QualMan is that it is flexible and scalable on a general-purpose workstation or PC. The disadvantage is the lack of very fine QoS granularity, which is only possible if supports are built inside the kernel. Our overall experience with QualMan design and experiments show that (1) the resource model in QualMan design is very scalable to different types of shared resources and platforms, and it allows a uniform view to embed the QoS inside distributed resource management semi; (2) the design and implementation of QualMan is easily portable semi; (3) the good results for QoS guarantees such as jitter, synchronization skew, and end-to-end delay, can be achieved for various distributed multimedia applications.
Analytical approach to custom datapath design
Authors: Serkan Askar, Maciej Ciesielski
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

This paper addresses the problem of layout design automation of datapath cells. We present a novel approach to transistor placement problem for custom datapath designs and demonstrate that it can be applied to practical designs. Our approach is based on an analytical model which employs a mixed integer linear programming (MILP) technique. The novelty and originality of the method is the efficient management of the complexity of the underlying mathematical model. Our prototype tool automatically handles transistor merging, folding, and intra-cell component sharing.
Teaching computer communication skills using case study method
Authors: Przemyslaw Polak
Venue: ACM SIGCSE Bulletin (1999)

Modern management activities involve extensive usage of computer communication services. The poster summarizes experience in teaching these skills on the basis of case study method. Two scenarios of computer game involving extensive usage of communication software and implementation of group decision making model are presented.
Small Parameter Limit for Discrete-Time Partially Observed Risk-Sensitive Control Problems
Authors: Francesca Albertini, Paolo Dai Pra
Venue: SIAM Journal on Control and Optimization (1999)

We show that risk-sensitive control problems and deterministic dynamic games can be connected, under rather mild assumptions, by a small noise limit. In order to control this limit, new techniques are developed to study propagation of large deviations through conditional probabilities.
Towards estimation error guarantees for distinct values
Authors: Moses Charikar, Surajit Chaudhuri, Rajeev Motwani, Vivek Narasayya
Venue: Proceedings of the nineteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems (2000)

We consider the problem of estimating the number of distinct values in a column of a table. For large tables without an index on the column, random sampling appears to be the only scalable approach for estimating the number of distinct values. We establish a powerful negative result stating that no estimator can guarantee small error across all input distributions, unless it examines a large fraction of the input data. In fact, any estimator must incur a significant error on at least some of a natural class of distributions. We then provide a new estimator which is provably optimal, in that its error is guaranteed to essentially match our negative result. A drawback of this estimator is that while its worst-case error is reasonable, it does not necessarily give the best possible error bound on any given distribution. Therefore, we develop heuristic estimators that are optimized for a class of typical input distributions. While these estimators lack strong guarantees on distribution-independent worst-case error, our extensive empirical comparison indicate their effectiveness both on real data sets and on synthetic data sets.
Toward a theory of maximally concurrent programs (shortened version)
Authors: Rajeev Joshi, Jayadev Misra
Venue: Proceedings of the nineteenth annual ACM symposium on Principles of distributed computing (2000)

Typically, program design involves constructing a program P that implements a given specification S; that is, the set P of executions of P is a subset of the set S of executions satisfying S. In many cases, we seek a program P that not only implements S, but for which P = S. Then, every execution satisfying the specification is a possible execution of the program; we then call P maximal for the specification S. We argue that maximality is an important criterion in the context of designing concurrent programs because it disallows implementations that do not exhibit enough concurrency. In addition, a maximal solution can serve as a basis for deriving a variety of implementations, each appropriate for execution on a specific computing platform. This paper also describes a method for proving the maximality of a program with respect to a given specification. Even though we prove facts about possible executions of programs, there is no need to appeal to branching time logics; we employ a fragment of linear temporal logic for our proofs. The method results in concise proofs of maximality for several non-trivial examples. The method may also serve as a guide in constructing maximal programs.
Querying network directories
Authors: H. V. Jagadish, Laks V. S. Lakshmanan, Tova Milo, Divesh Srivastava, Dimitra Vista
Venue: ACM SIGMOD Record (1999)

Heirarchically structured directories have recently proliferated with the growth of the Internet, and are being used to store not only address books and contact information for people, but also personal profiles, network resource information, and network and service policies. These systems provide a means for managing scale and heterogeneity, while allowing for conceptual unity and autonomy across multiple directory servers in the network, in a way for superior to what conventional relational or object-oriented databases offer. Yet, in deployed systems today, much of the data is modeled in an ad hoc manner, and many of the more sophisticated &ldquo;queries&rdquo; involve navigational access. In this paper, we develop the core of a formal data model for network directories, and propose a sequence of efficiently computable query languages with increasing expressive power. The directory data model can naturally represent rich forms of heterogeneity exhibited in the real world. Answers to queries expressible in our query languages can exhibit the same kinds of heterogeneity. We present external memory algorithms for the evaluation of queries posed in our directory query languages, and prove the efficiency of each algorithm in terms of its I/O complexity. Our data model and query languages share the flexibility and utility of the recent proposals for semi-structured data models, while at the same time effectively addressing the specific needs of network directory applications, which we demonstrate by means of a representative real-life example.
BlurFit: an application of functional programming to scientific analysis
Authors: D. McClain
Venue: ACM SIGPLAN Notices (1999)

Functional languages offer numerous advantages when applied to scientific programming. Significant reductions in the complexity of the problem expression are possible. The speed of execution is competitive with native C code. The use of a functional programming style allows the investigator to concentrate more on the scientific problem and less on its expression in a computer language. These characteristics were clearly demonstrated in our version of the BlurFit algorithm written in the OCaml language.
Frequency Filtering for Elliptic Interface Problems with Lagrange Multipliers
Authors: B. N. Khoromskij, G. E. Mazurkevich, G. Wittum
Venue: SIAM Journal on Scientific Computing (1999)

The solution of the saddle point interface problem arising in hybrid formulation with the Lagrange multipliers for elliptic problems with nonmatching grids is considered. The preconditioner is constructed using frequency filtering decompositions of the local Schur complements. The convergence rate of the resulting iterative process does not depend on the size of the interface problem. The approach is applied for the treatment of the local refinement procedures and considered as an alternative to the refinement with slave nodes or full closure of the grid. Numerical experiments on the convergence rate are presented.
SARA in the design room
Authors: Gerald Estrin
Venue: Proceedings of the 1985 ACM thirteenth annual conference on Computer Science (1985)

This paper presents an overview of SARA (System ARchitects Apprentice), an interactive environment which was created so that designers might enhance their capabilities to effectively design concurrent computer systems. SARA's requirements, methodology, support tools, and experiences are summarized in turn. The paper ends with a discussion of collaborative capabilities needed in the &ldquo;design room&rdquo;.
A scalable substrate noise coupling model for mixed-signal ICs
Authors: Anil Samavedam, Karti Mayaram, Terri Fiez
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

A scalable macromodel for substrate noise coupling in heavily doped substrates has been developed. This model is simple since it requires only four parameters which can readily be extracted from a small number of device simulations or measurements. Once these parameters have been determined the model can be used for any spacing between the injection and sensing contacts and for different contact geometries. The scalability of the model with separation and width provides insight into substrate coupling and optimization issues prior to and during the layout phase. The model is validated for a 2&mgr;m and a 0.5&mgr;m CMOS process where it is shown that the simple model predicts the noise coupling accurately. Measurements from a chip fabricated in a 0.5&mgr;m CMOS process show good agreement with the model.
Feature Detection with Automatic Scale Selection
Authors: Tony Lindeberg
Venue: International Journal of Computer Vision (1998)

The fact that objects in the world appear in different ways depending on the scale of observation has important implications if one aims at describing them. It shows that the notion of scale is of utmost importance when processing unknown measurement data by automatic methods. In their seminal works, Witkin (1983) and Koenderink (1984) proposed to approach this problem by representing image structures at different scales in a so-called scale-space representation. Traditional scale-space theory building on this work, however, does not address the problem of how to select local appropriate scales for further analysis. This article proposes a systematic methodology for dealing with this problem. A framework is presented for generating hypotheses about interesting scale levels in image data, based on a general principle stating that local extrema over scales of different combinations of &gamma;-normalized derivatives are likely candidates to correspond to interesting structures. Specifically, it is shown how this idea can be used as a major mechanism in algorithms for automatic scale selection, which adapt the local scales of processing to the local image structure.Support for the proposed approach is given in terms of a general theoretical investigation of the behaviour of the scale selection method under rescalings of the input pattern and by integration with different types of early visual modules, including experiments on real-world and synthetic data. Support is also given by a detailed analysis of how different types of feature detectors perform when integrated with a scale selection mechanism and then applied to characteristic model patterns. Specifically, it is described in detail how the proposed methodology applies to the problems of blob detection, junction detection, edge detection, ridge detection and local frequency estimation.In many computer vision applications, the poor performance of the low-level vision modules constitutes a major bottleneck. It is argued that the inclusion of mechanisms for automatic scale selection is essential if we are to construct vision systems to automatically analyse complex unknown environments.
KWM: Knowledge-based Workflow Model for Agile Organization
Authors: Ha Bin Lee, Jong Woo Kim, Sung Joo Park
Venue: Journal of Intelligent Information Systems (1999)

The workflow management system (WFMS) in an agile organization should be highly adaptable to the frequent organizational changes. To increase the adaptability of contemporary WFMSs, a mechanism for managing changes within the organizational structure and changes in business rules needs to be reinforced. In this paper, a knowledge-based approach for workflow modeling is proposed, in which a workflow is defined as a set of business rules. Knowledge on the organizational structure and special workflow, such as role/actor mappings and complex routing rules, can be explicitly modeled in KWM (Knowledge-based Workflow Model). Using knowledge representation scheme and dependency management facility, a change propagation mechanism is provided to adapt to the frequent changes in the organizational structure, business rules, and procedures.
A simple algorithm for partial redundancy elimination
Authors: Vineeth Kumar Paleri, Y. N. Srikant, Priti Shankar
Venue: ACM SIGPLAN Notices (1998)

Partial redundancy elimination was originally formulated as a bidirectional, bit-vector, data-flow analysis problem by Morel and Renvoise. Dhamdhere improved the original algorithm using the concept of edge placement. Knoop, R uuml;thing, and Steffen viewed the problem within a framework that required only four unidirectional analyses for an optimal solution. Here, we propose an algorithm for partial redundancy elimination based on well known concepts, viz., availability, anticipability, partial availability, and partial anticipability. The algorithm is both computationally and lifetime optimal. Our algorithm also requires four unidirectional data-flow analyses. The main advantage of the algorithm is its simplicity.
Decision-Making With and Without Information Technology in Acute Care Hospitals: Survey in the United States
Authors: Myron Hatcher
Venue: Journal of Medical Systems (1998)

These survey results are from a national survey of acute care hospitals. A random sample of 813 hospitals was selected with 115 responding and 33 incorrect addresses resulting in a 15% response rate. The purpose of the study was to measure the extent of information systems integration in the financial, medical, and administrative systems of the hospitals. Decision making with and without information technology is explored based upon the survey data. The results indicate why and how meetings are held. Necessary changes in the decision-making environment are identified for decision making utilizing information technology to be successful. These results will provide a benchmark for hospitals to determine their technology transfer position and to set goals for computer assisted decision-making.