ppxscal/embedding_network huggingface dataset:
Flexible architectures for CSCW system support
Authors: Richard Bentley
Venue: ACM SIGOIS Bulletin (1995)

Despite the widespread attention CSCW has received from researchers and product developers there have been very few examples of successful cooperative applications. This lack of success can be attributed in part to the lack of principles we have for CSCW system development. Identification of such principles requires a better understanding of the core functionality required to support group work. My own belief is that tools which allow developers to experiment with different strategies to support cooperation, such as alternative approaches to information sharing and presentation, update propagation, synchronisation and so on, would contribute significantly to this understanding. As such I advocate an approach to the development of cooperative systems based on prototyping, and I see this as complementary to other work focusing on discovering and articulating social interaction in order to better inform cooperative system development.Cooperative applications place novel requirements on supporting architectures, over and above those of more traditional multi-user systems. One such requirement is the need for a high degree of flexibility, necessary to support different end-users, engaged in different tasks and often adopting different methods of working. This requirement for flexibility is emphasised if we consider toolkits and environments intended to support experimentation with different strategies for managing and promoting cooperative interaction.In this brief exposition I will attempt to support my position which is based on the need for experimental prototyping of cooperative systems, and justify the claim that this prototyping requires more flexible software architectures. My thinking in this area to date has been shaped largely by experiences gained in developing the MEAD multi-user interface prototyping environment at Lancaster University. Although the MEAD system proved useful for prototyping user interfaces to support the cooperative work of air traffic controllers, it is limited in the range of cooperative interaction which can be supported. In this respect I believe MEAD is similar to most other platforms supporting development of cooperative systems.
Comment on Using the Uniformity Measure for Performance Measure in Image Segmentation
Authors: W. S. Ng, C. K. Lee
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1996)

In this correspondence, we will point out that the image segmentation performance measure¿the uniformity measure, which is suggested by Levine and Nazif [1]¿is basically equivalent to the criterion measure proposed by Otsu [2].
Pointing in entertainment-oriented environments: appreciation versus performance
Authors: J. H. D. M. Westerink, K. van den Reek
Venue: ACM SIGCHI Bulletin (1995)

Multimedia applications for consumer entertainment often employ a point-and-select interaction style, borrowed from more task-oriented computer applications. The environment of use and the pointing devices involved are so different, however, that a higher importance should be attributed to the users' appreciation of the pointing device than to its efficiency or any other objective performance measure. We set up an experiment to investigate how appreciation and performance measures relate. The experiment involved six different input devices, two CD-i titles and 16 subjects making both voluntary and prescribed cursor control movements. For the mouse-like pointing devices we obtained a Fitts' Law-like dependence on target width and target distance. This was, however, not replicated for any of the other input devices, mainly owing to a positive influence of cursor constraints. Concerning the relation of the performance measures with the users' appreciation, we found that neither time-to-target nor relative-path-length on its own is a reliable indicator of the users' appreciation. Together, however, they might explain the appreciation scores to a considerable extent.
Layout based model generation
Authors: Peter Lorenz, Thomas Schulze
Venue: Proceedings of the 27th conference on Winter simulation (1995)

Layouts of systems (e.g. barber shops, job shop, road traffic and copper smelter) contain information important for modelling. Layout based model generation (LBMG) entails: extracting all model relevant data from layouts, complementing the initial layout by simulation specific components, extracting additional model relevant data from other data sources, generating a simulation model from these extraction's, asking the user for complementary input data, running the simulation model, and presenting the simulation results and animation on the layout, generated in the second step. The paper describes an efficient approach to simulation modelling. This approach intends to avoid any doubled or repeated data acquisition and any avoidable mouse click or drop and drug. The modeler can make precise, realistic models with little cost in terms of time or money. The models that are created are now free of bugs that are normally introduced by the manual model construction and data acquisition process. The preconditions for LBMG are the the existence of a defined set of object classes in the domain of application and the existence of layouts or other pictures which contain model relevant information and which are of interest for the presentation of results by animation. The first ideas for LBMG were described by Lorenz, Schriber and Schulze (1994) and by Lorenz and Schulze (1995). The LBMG approach is described and verified by the implementation of a prototype. The prototype uses AutoCAD, DXF and Proof Layout file types as the layout basis for model generation. The approach can be used for any simulator with a language oriented model description interface, e.g. GPSS/H, MODSIM, SIMAN and other simulation systems.
Machine Learning Approaches to Estimating Software Development Effort
Authors: Krishnamoorthy Srinivasan, Douglas Fisher
Venue: IEEE Transactions on Software Engineering (1995)

Accurate estimation of software development effort is critical in software engineering. Underestimates lead to time pressures that may compromise full functional development and thorough testing of software. In contrast, overestimates can result in noncompetitive contract bids and/or over allocation of development resources and personnel. As a result, many models for estimating software development effort have been proposed. This article describes two methods of machine learning, which we use to build estimators of software development effort from historical data. Our experiments indicate that these techniques are competitive with traditional estimators on one dataset, but also illustrate that these methods are sensitive to the data on which they are trained. This cautionary note applies to any model-construction strategy that relies on historical data. All such models for software effort estimation should be evaluated by exploring model sensitivity on a variety of historical data.
A framework for formalizing inconsistencies and deviations in human-centered systems
Authors: Gianpaolo Cugola, Elisabetta Di Nitto, Alfonso Fuggetta, Carlo Ghezzi
Venue: ACM Transactions on Software Engineering and Methodology (TOSEM) (1996)

Most modern business activities are carried out by a combination of computerized tools and human agents. Typical examples are engineering design activities, office procedures, and banking systems. All these human-centered systems are characterized by the interaction among people, and between people and computerized tools. This interaction defines a process, whose effectiveness is essential to ensure the quality of the delivered products and/or services. To support these systems, process-centered environments and workflow management systems have been recently developed. They can be collectively identified with the term process technology. This technology is based on the explicit definition of the process to be followed (the process model). The model specifies the kind of support that has to be provided to human agents. An essential property that process technology mut exhibit is the ability of tolerating, controlling, and supporting deviations and inconsistencies of the real-world behaviors with respect to the proocess model. This is necessary to provide consistent and effective support to the human-centered system, still maintaining a high degree of flexibility and adaptability to the evolving needs, preferences, an expertise of the the human agents. This article presents a formal framework to characterize the interaction between a human-centered system and its automated support. It does not aim at introducing a new language or system to describe processes. Rather, it aims at identifying the basic properties and features that make it possible to formally define the concepts of inconsistency and deviation. This formal framework can then be used to compare existing solutions and guide future research work.
Inspections of formal specifications
Authors: Thomas B. Hilburn
Venue: ACM SIGCSE Bulletin (1996)

This paper describes a student peer review process that has been incorporated within an introductory course in formal methods. As a course project, a team of students develops a formal specification of the requirements for a software system. The final part of the project involves the inspection of the specification by another team of student reviewers. The paper presents a rationale for including inspections as part of a formal methods course. It provides a detailed description of the inspection process and reports on the application of the process to a specific class project. Finally, the paper assesses the results of the use of such a paradigm and discusses how to improve it.
Sequential patterns in information systems development: an application of a social process model
Authors: Daniel Robey, Michael Newman
Venue: ACM Transactions on Information Systems (TOIS) (1996)

We trace the process of developing and implementing a materials management system in one company over a 15-year period. Using a process research model developed by Newman and Robey, we identify 44 events in the process and define them as either encounters or episodes. Encounters are concentrated events, such as meetings and announcements, that separate episodes, which are events of longer duration. By examining the sequence of events over the 15 years of the case, we identify a pattern of repeated failure, followed by success. Our discussion centers on the value of detecting and displaying such patterns and the need for theoretical interpretation of recurring sequences of events. Five alternative theoretical perspectives, originally proposed by Kling, are used to interpret the sequential patterns identified by the model. We conclude that the form of the process model allows researchers who operate from different perspectives to enrich their understanding of the process of system development.
Multivalent digital documents in UC Berkeley's digital library project
Authors: Thomas A. Phelps, Robert Wilensky
Venue: ACM SIGWEB Newsletter (1995)

UC Berkeley's Digital Library Project aims to develop the technologies to incorporate the use of massive, distributed, multimedia repositories into tasks to be performed by groups of users. We call this approach "work-centered digital libraries". To develop this approach, we have been constructing a testbed focused on the California environment. This testbed involves real users from a variety of backgrounds, and a large collection of diverse kinds of data of interest to them, including environmental technical reports, computer models, county general plans, aerial and ground photography, maps, videos and databases about California biota. Our project has broad technical objectives, seeking to incorporate in an advanced database framework better information extraction and access technology, including document recognition, natural language and computer vision techniques, supplemented with advanced user interface and authoring tools. One element of this work is a new, higher functionality model for digital documents.
Dover: An Optimal On-Line Scheduling Algorithm for Overloaded Uniprocessor Real-Time Systems
Authors: Gilad Koren, Dennis Shasha
Venue: SIAM Journal on Computing (1995)

Consider a real-time system in which every task has a value that it obtains only if it completes by its deadline. The problem is to design an on-line scheduling algorithm (i.e., the scheduler has no knowledge of a task until it is released) that maximizes the guaranteed value obtained by the system. When such a system is underloaded (i.e., there exists a schedule for which all tasks meet their deadlines), Dertouzos [Proceedings IFIF Congress, 1974, pp.\ 807--813] showed that the earliest deadline first algorithm will achieve 100% of the possible value. Locke [Ph. D. thesis, Computer Science Dept., Carnegie-Mellon Univ., Pittsburgh, PA] showed that earliest deadline first performs very badly, however, when the system is overloaded, and he proposed heuristics to deal with overload. This paper presents an optimal on-line scheduling algorithm for overloaded uniprocessor systems. It is optimal in the sense that it gives the best competitive ratio possible relative to an off-line scheduler.
Correlation and aliasing in dynamic branch predictors
Authors: Stuart Sechrest, Chih-Chieh Lee, Trevor Mudge
Venue: Proceedings of the 23rd annual international symposium on Computer architecture (1996)

Previous branch prediction studies have relied primarily upon the SPECint89 and SPECint92 benchmarks for evaluation. Most of these benchmarks exercise a very small amount of code. As a consequence, the resources required by these schemes for accurate predictions of larger programs have not been clear. Moreover, many of these studies have simulated a very limited number of configurations. Here we report on simulations of a variety of branch prediction schemes using a set of relatively large benchmark programs that we believe to be more representative of likely system workloads. We have examined the sensitivity of these prediction schemes to variation in workload, in resources, and in design and configuration. We show that for predictors with small available resources, aliasing between distinct branches can have the dominant influence on prediction accuracy. For global history based schemes, such as GAs and gshare, aliasing in the predictor table can eliminate any advantage gained through inter branch correlation. For self-history based prediction scheme, such as PAs, it is aliasing in the buffer recording branch history, rather than the predictor table, that poses problems. Past studies have sometimes confused these effects and allocated resources incorrectly.
The unconventional replacement algorithms
Authors: Humayun Khalid
Venue: ACM SIGARCH Computer Architecture News (1995)

This work proposes several new schemes for the replacement of cache lines/blocks in high performance computer systems. Our algorithms rely on judiciously chosen neural networks for accurate real-time statistical predictions. These algorithms, therefore, provide better cache performance as compared to the conventional LRU (Least Recently Used) algorithm. Simulation results indicate that the proposed set of replacement strategies can provide a performance improvement of as much as 16.4711% over the LRU algorithm for our selected benchmark trace files. The results are based on an experimentation involving 6 neural network paradigms and 21 different cache configurations. Excellent performance of the neural network-based replacement strategies means that this new approach can be studied as an alternative to the existing page replacement and prefetching algorithms in virtual memory systems.
Computing in Vietnam: an Asian tiger in the rough
Authors: S. E. Goodman, L. I. Press
Venue: Communications of the ACM (1995)

Nguyen Dinh Ngoc and Dang Huu were among the senior technology leaders at the Fourth Informatics Week conference and exhibition held in Ho Chi Minh City (HCMC) in August 1994, an event that swarmed with teenagers, young techies, and businessmen.
NPSI adaptive synchronization algorithms for PDES
Authors: Sudhir Srinivasan, Paul F. Reynolds,  Jr.
Venue: Proceedings of the 27th conference on Winter simulation (1995)

Adaptive approaches to synchronization in parallel discrete event simulations hold significant potential for performance improvement. We contend that an adaptive approach based on low cost near-perfect system state information is the most likely to yield a consistently efficient synchronization algorithm. We suggest a framework by which NPSI (near-perfect state information) adaptive protocols could be designed and describe the first such protocol-elastic time algorithm. We present performance results which show that NPSI protocols are very promising. In particular, they have the capacity to outperform time warp consistently in both time and space.
On the Stability of the Bareiss and Related Toeplitz Factorization Algorithms
Authors: A. W. Bojanczyk, R. P. Brent, F. R. de Hoog, D. R. Sweet
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

This paper contains a numerical stability analysis of factorization algorithms for computing the Cholesky decomposition of symmetric positive definite matrices of displacement rank 2. The algorithms in the class can be expressed as sequences of elementary downdating steps. The stability of the factorization algorithms follows directly from the numerical properties of algorithms for realizing elementary downdating operations. It is shown that the Bareiss algorithm for factorizing a symmetric positive definite Toeplitz matrix is in the class and hence the Bareiss algorithm is stable. Some numerical experiments that compare behavior of the Bareiss algorithm and the Levinson algorithm are presented. These experiments indicate that generally (when the reflection coefficients are not all of the same sign) the Levinson algorithm can give much larger residuals than the Bareiss algorithm.
Building testable software
Authors: Lin Zucconi, Karl Reed
Venue: ACM SIGSOFT Software Engineering Notes (1996)

This paper examines a connection between well known specification, design, implementation methodologies and test-design which appears not to have been previously well-formulated. We refer to the fact that the use of finite state machines (FSMs) in each development phase (specification, design, implementation and testing) is well known and documented. However, despite the fact that much of this work is more than twenty years old, there appears to be no detailed proposal for a consistent FSM-based approach be used across all development phases for other than very specific application types. We suggest that the adoption of a systematic FSM-based approach across all phases, including implementation, may allow a number of major problems in software development to be either eliminated or simplified. In this way, testable, highly dependable systems can be produced. In such systems, behaviour is explicitly defined, built, and tested using both functional and structural methods. Undesired behaviours can be found and eliminated, and abnormal or unexpected input explicitly handled. We discuss the issues we consider to be involved, and the benefits which we expect may be gained. We also identify those areas where further work appears to be required.
Efficient routing in optical networks
Authors: Alok Aggarwal, Amotz Bar-Noy, Don Coppersmith, Rajiv Ramaswami, Baruch Schieber, Madhu Sudan
Venue: Journal of the ACM (JACM) (1996)

This paper studies the problem of dedicating routes to connections in optical networks. In optical networks, the vast bandwidth available in an optical fiber is utilized by partitioning it into several channels, each at a different optical wavelength. A connection between two nodes is assigned a specific wavelength, with the constraint that no two connections sharing a link in the network can be assigned the same wavelength. This paper considers optical networks with and without switches, and different types of routing in these networks. It presents optimal or near-optimal constructions of optical networks in these cases and algorithms for routing connections, specifically permutation routing for the networks constructed here.
High-energy physics on DECPeRLe-1 programmable active memory
Authors: Laurent Moll, Jean Vuillemin, Philippe Boucard
Venue: Proceedings of the 1995 ACM third international symposium on Field-programmable gate arrays (1995)

The future Large Hadron Collider (LHC) to be built at CERN, by the turn of the millenium, provides an ample source of challenging real-time computational problems. We report here some results from a collaboration between CERN EAST (RD-11) group and DEC-PRL PAM team. We present the implementations of the three foremost LHC algorithms on DECPeRLe-1 [2]. Our machine is the only one which presently meets the requirements from CERN (100 kHz event rate), except for another dedicated FPGA-based board built for just one of the algorithm. All other implementations based on single and multiprocessor general purpose computing systems fall short either of computing power, or of I/O resources or both.
A new look at pattern matching in abstract data types
Authors: Pedro Palao Gostanza, Ricardo Peña, Manuel Núñez
Venue: Proceedings of the first ACM SIGPLAN international conference on Functional programming (1996)

In this paper we present a construction smoothly integrating pattern matching with abstract data types. We review some previous proposals [19, 23, 20, 6, 1] and their drawbacks, and show how our proposal can solve them. In particular we pay attention to equational reasoning about programs containing this new facility. We also give its formal syntax and semantics, as well as some guidelines in order to compile the construction efficiently.
Exact Observability of the Time-Varying Hyperbolic Equation with Finitely Many Moving Internal Observations
Authors: A. Yu. Khapalov
Venue: SIAM Journal on Control and Optimization (1995)

The problem of exact observability of the linear hyperbolic equation with time-varying coefficients under finitely many internal observations is considered. The question with which we are concerned in this paper is a sharp correspondence between the internal regularity of the solutions and a type of observation required to provide $L^\infty(0,T; R^{n+1})$- or $C([0,T[; R^{n+1})$-exact observability with respect to the energy norm. Two types of observations are considered: pointwise and spatially averaged, for which the existence of needed observation curves (continuous on $[0,T[$ for $n=1$) and set-valued maps (continuous on $[0,T[$ with respect to Lebesgue measure) is established. The techniques involved are related to the construction of suitable skeletons for these curves and maps.
Interactive teaching modules for computer graphics
Authors: Avi C. Naiman
Venue: ACM SIGGRAPH Computer Graphics (1996)

We are developing a suite of interactive modules for teaching introductory computer graphics, using a library we have built to support such efforts. The modules provide explanations of fundamental concepts, tutorial demonstrations of basic techniques and interactive control of the parameters used in and execution of high level representations of elementary algorithms. The modules are used in laboratory sessions to supplement formal lectures. Here, we present our philosophy in building the library and modules, discuss the lessons we have learned in our initial implementation and outline our future plans.