ppxscal/embedding_network huggingface dataset:
Performance optimization under rise and fall parameters
Authors: Rajeev Murgai
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

Typically, cell parameters such as the pin-to-pin intrinsic delays, load-dependent coefficients, and input pin capacitances have different values for rising and falling signals. The performance optimization algorithms, however, assume a single value for each parameter. No work has been done to study the impact of separate rise and fall values on the complexity of optimization. In this paper, we take the first step towards understanding this impact. We pick two problems that have polynomial-time complexities if a single value for each cell parameter is assumed. The first problem is that of buffer insertion on a fixed topology net to maximize the required time at the source of the net. The second is the gate resizing problem (and the more general technology mapping problem) for minimizing the circuit delay under the simplest, load-independent delay model. We show that under separate rise and fall parameters, both these problems become NP-complete. To the best of our knowledge, this is the first such result showing the effect of rise and fall parameters on the complexity of performance optimization problems. We then address the important question of devising a good practical algorithm for local fanout optimization.
Simulation in software engineering training
Authors: Anke Drappa, Jochen Ludewig
Venue: Proceedings of the 22nd international conference on Software engineering (2000)

Simulation is frequently used for training in many application areas like aviation and economics, but not in software engineering. We present the SESAM project which focuses on software engineering education using simulation. In the SESAM project a simulator was developed. Using this simulator, a student can take the role of a software project manager. The simulated software project can be finished within a couple of hours because it is simulated in &ldquo;quick-motion&rdquo; mode.In this paper, the background and goals of the SESAM project are presented. A new simulation model, the so called QA model, is introduced. The model behavior is demonstrated by investigating and comparing different strategies for software development. The results of experiments based on the QA model are reported. Finally, conclusions are drawn from the experiments and future work is outlined.
Conditioning of Rectangular Vandermonde Matrices with Nodes in the Unit Disk
Authors: Fermín S. V. Bazán
Venue: SIAM Journal on Matrix Analysis and Applications (1999)

Let WN=WN(z1,z2, . . . z1) be a rectangular Vandermonde matrix of order n &times; N, $N\geq n,$ with distinct nodes zj in the unit disk and $z_j^{k-1}$ as its (j,k) entry. Matrices of this type often arise in frequency estimation and system identification problems. In this paper, the conditioning of WN is analyzed and bounds for the spectral condition number $\kappa_2(W_N)$ are derived. The bounds depend on n, N, and the separation of the nodes. By analyzing the behavior of the bounds as functions of N, we conclude that these matrices may become well conditioned, provided the nodes are close to the unit circle but not extremely close to each other and provided the number of columns of WN is large enough. The asymptotic behavior of both the conditioning itself and the bounds is analyzed and the theoretical results arising from this analysis verified by numerical examples.
A flexible authorization mechanism for relational data management systems
Authors: Elisa Bertino, Sushil Jajodia, Pierangela Samarati
Venue: ACM Transactions on Information Systems (TOIS) (1999)

In this article, we present an authorization model that can be used to express a number of discretionary access control policies for relational data management systems. The model permits both positive and negative authorizations and supports exceptions at the same time. The model is flexible in that the users can specify, for each authorization they grant, whether the authorization can allow for exceptions or whether it must be strongly obeyed. It provides authorization management for groups with exceptions at any level of the group hierarchy, and temporary suspension of authorizations. The model supports ownership together with decentralized administration of authorizations. Administrative privileges can also be restricted so that owners retain control over their tables.
Foundations 2025: a Value Model for Evaluating Future Air and Space Forces
Authors: Gregory S. Parnell, Harry W. Conley, Jack A. Jackson, Lee J. Lehmkul, John M. Andrew
Venue: Management Science (1998)

Air Force 2025 was a study directed by the Chief of Staff of the United States Air Force to identify key system concepts and technologies for achieving air and space dominance in the year 2025. The study was a large effort in which over 200 military experts participated for more than one year. We developed a Value-Focused Thinking model, which we used to evaluate which futuristic system concepts have the greatest potential to ensure future U.S. air and space dominance. We named the value model Foundations 2025 because it represented a return to the basics of air and space dominance. We used the "silver standard" approach for value hierarchy development. The participants identified key verbs to describe tasks that must be performed in 2025 to ensure air and space dominance. The value hierarchy was developed bottom-up by aggregating these verbs into higher order tasks using affinity diagrams. Using the value hierarchy, we used multiattribute decision analysis techniques to develop an additive value model with 134 attributes. The Foundations 2025 value model was successfully used to score 43 futuristic system concepts and provide insights about the most promising system concepts and technologies. The analysis results directly supported the study director and the senior leadership of the United States Air Force.
Global and Local Active Contours for Head Boundary Extraction
Authors: Steve R. Gunn, Mark S. Nixon
Venue: International Journal of Computer Vision (1998)

Active contours are an attractive choice to extract the head boundary, for deployment within a face recognition or model-based coding scenario. However, conventional snake approaches can suffer difficulty in initialisation and parameterisation. A dual active contour configuration using dynamic programming has been developed to resolve these difficulties by using a global energy minimisation technique and a simplified parameterisation, to enable a global solution to be obtained. The merits of conventional gradient descent based snake (local) approaches, and search-based (global) approaches are discussed. In application to find head and face boundaries in front-view face images, the new technique employing dynamic programming is deployed to extract the inner face boundary, along with a conventional normal-driven contour to extract the outer (head) boundary. The extracted contours appear to offer sufficient discriminatory capability for inclusion within an automatic face recognition system.
Colearning in Differential Games
Authors: John W. Sheppard
Venue: Machine Learning (1998)

Game playing has been a popular problem area for research in artificial intelligence and machine learning for many years. In almost every study of game playing and machine learning, the focus has been on games with a finite set of states and a finite set of actions. Further, most of this research has focused on a single player or team learning how to play against another player or team that is applying a fixed strategy for playing the game. In this paper, we explore multiagent learning in the context of game playing and develop algorithms for &ldquo;co-learning&rdquo; in which all players attempt to learn their optimal strategies simultaneously. Specifically, we address two approaches to colearning, demonstrating strong performance by a memory-based reinforcement learner and comparable but faster performance with a tree-based reinforcement learner.
1/k phase stamping for continuous shared data (extended abstract)
Authors: Sumeer Bhola, Mustaque Ahamad
Venue: Proceedings of the nineteenth annual ACM symposium on Principles of distributed computing (2000)

Interactive distributed applications are a relatively new class of applications that are enabled by sharing continuously evolving data across distributed sites (and users). The characteristics of application data include very fine-grained updates that can atomically access a subset of the shared data, masking of update effects, and irregular locality and contention for access. Existing programming approaches are not appropriate for programming such continuous shared data in a wide-area environment. We define an object-set abstraction, where a set is replicated at sites interested in the objects, and is modified using add, delete and update operations. The key features of this abstraction are issue-time access information for update operations, and the potential for replicating the computation associated with updates. Ordering of operations is an important problem, and we present a fast, scalable ordering algorithm, 1/k phase stamping, that uses distributed tokens that correspond to objects in the set. This algorithm provides substantially better performance than alternative algorithms, is deadlock and abort free, and requires no queuing at the tokens. Therefore, tokens can be located inside a programmable 'active' network. The precise stamps generated with 1/k phase stamping enable a dynamic communication optimization technique, effect and stamp merging, which can reduce communication and allow utilization of best-effort message delivery. These algorithms have been implemented in the RAGA system which can tolerate crash failures.
Nonsmooth Duality, Sandwich, and Squeeze Theorems
Authors: A. S. Lewis, R. E. Lucchetti
Venue: SIAM Journal on Control and Optimization (2000)

Given a nonlinear function h separating a convex and a concave function, we provide various conditions under which there exists an affine separating function whose graph is somewhere almost parallel to the graph of h. Such results blend Fenchel duality with a variational principle and are closely related to the Clarke--Ledyaev mean value inequality.
Solutions and Ambiguities of the Structure and Motion Problem for 1DRetinal Vision
Authors: Kalle åström, Magnus Oskarsson
Venue: Journal of Mathematical Imaging and Vision (2000)

In this paper we investigate the geometry and algebra of multiple one-dimensional projections of a two-dimensional environment. This is relevant for one-dimensional cameras, e.g. as used in certain autonomous guided vehicles. It is also relevant for understanding the projection of lines in ordinary vision. A third application is on ordinary vision of vehicles undergoing so called planar motion. The structure and motion problem for such cameras is studied and the two possible minimal cases is solved. The technique of solving these questions reveal interesting ambiguities. It is shown that for each solution with three images there is an ambiguous solution. It is also shown that for each solution for four points there is an ambiguous solution. The connection between these two different types of ambiguities is also given. Although the paper deals with calibrated cameras, it is shown that similar results exist for uncalibrated cameras.
Interface and data architecture for query preview in networked information systems
Authors: Catherine Plaisant, Ben Shneiderman, Khoa Doan, Tom Bruns
Venue: ACM Transactions on Information Systems (TOIS) (1999)

There are numerous problems associated with formulating queries on networked information systems. These include increased data volume and complexity, accompanied by slow network access. This article proposes a new approach to a network query user interfaces that consists of two phases: query preview and query refinement. This new approach is based on the concepts of dynamic queries and query previews, which guides users in rapidly and dynamically eliminating undesired records, reducing the data volume to a manageable size, and refining queries locally before submission over a network. Examples of two applications are given: a Restaurant Finder and a prototype for NASA's Earth Observing Systems Data Information Systems (EOSDIS). Data architecture is discussed, and user feedback is presented.
When Shadows Become Interreflections
Authors: M. S. Langer
Venue: International Journal of Computer Vision (1999)

Shadows and interreflections are present in all real scenes and provide a rich set of photometric cues for vision. In this paper, we show how shadows and interreflections are intrinsically related. Shadows tend to occur in those parts of a scene in which interreflections have the largest gain. We provide several basic results concerning this relationship in terms of the interreflection modes of a scene. We show that for a given scene, the interreflection mode having the largest gain is a physically realizable radiance function. We derive bounds on the gain of this mode and discuss how this mode is related to shadows. We analyze how well an n-bounce model of interreflections approximates an infinite-bounce model and how shadows affect this approximation. Finally, we introduce a novel method for inferring surface color in a uni-chromatic scene. The method is based on the relative contrast of the scene in different color channels.
Iterative Substructuring for Hypersingular Integral Equations in $\Bbb R^3$
Authors: Norbert Heuer, Ernst P. Stephan
Venue: SIAM Journal on Scientific Computing (1998)

We study a preconditioner for the h-version of the boundary element method for hypersingular integral equations in three dimensions. Our preconditioner is based on iterative substructuring which forms an important part of the domain decomposition technique. We prove a bound for the improved condition numbers which behaves polylogarithmically in H/h. Here H is the size of the subdomains and h is the size of the elements used to construct the boundary element spaces. Numerical results which support our theory are reported.
Stair Matrices and Their Generalizations with Applications to Iterative Methods I: A Generalization of the Successive Overrelaxation Method
Authors: Hao Lu
Venue: SIAM Journal on Numerical Analysis (1999)

Stair matrices and their generalizations are introduced. Some properties of the matrices are presented. Like triangular matrices this class of matrices provides bases of matrix splittings for iterative methods. A remarkable feature of iterative methods based on the new class of matrices is that the methods are easily implemented for parallel computation. In particular, a generalization of the successive overrelaxation (SOR) method is introduced. The SOR theory on determination of the optimal parameter is extended to the generalized method to include a wide class of matrices. The asymptotic rate of convergence of the new method is derived for Hermitian positive definite matrices using bounds of the eigenvalues of Jacobi matrices and numerical radius. Finally, numerical tests are presented to corroborate the obtained results.
An Integrated Hardware/Software Data Prefetching Scheme for Shared-Memory Multiprocessors
Authors: Edward H. Gornish, Alexander Veidenbaum
Venue: International Journal of Parallel Programming (1999)

Both hardware and software prefetching have been shown to be effective in tolerating the large memory latencies inherent in shared-memory multiprocessors; however, both types of prefetching have their shortcomings. While software schemes require less hardware support than hardware schemes, they must generate address calculation instructions and a prefetch instruction for each datum that needs to be prefetched. Hardware schemes, however, must become progressively more complex to be able to compute data access strides and to increase the prefetching lookahead. In this paper, we propose an integrated hardware/software prefetching method that uses simple hardware that can handle most data accesses and software prefetching for the few remaining accesses. A compile time algorithm analyzes the access streams formed by array references and determines sequences of consecutive memory accesses to an access stream that can be prefetched by the hardware mechanism. This analysis is based on the relative memory locations of consecutive accesses to an access stream and the number of intervening data references between consecutive accesses to an access stream. In addition, the prefetching lookahead can be set separately for each access stream. Our approach yields an effective scheme that minimizes both CPU overhead and hardware costs. Execution-driven simulations show our method to be very effective.
Effective use of wireless data communications
Authors: Geoffrey Engerman, Lee Kearney
Venue: International Journal of Network Management (1998)

This article summarizes the various wireless data network technologies and describes the underlying data communication elements necessary for effective application deployment. &copy; 1998 John Wiley & Sons, Ltd.
A middleware overview: goals, research issues, and coded examples (abstract)
Authors: Michael Ogg
Venue: Proceedings of the nineteenth annual ACM symposium on Principles of distributed computing (2000)

In this tutorial, I will focus on the roles, types, and issues of middleware. I will give a short overview of the software problems that middleware addresses and (mostly) solves. I will do a survey of the different kinds of middleware and their applicability to diverse problem domains. I will spend somewhat longer discussing, with examples, CORBA, RMI, and Jini, in particular pointing out relative strengths and weaknesses. Finally, I will discuss some of the major and outstanding research issues, especially those that a PODC audience might find stimulating, and suggest where and how solutions might be found.
Ada 95 conformity assessment - Phil Brashear
Authors: Randall Brukardt, Steven Deller, Joyce L. Tokar
Venue: ACM SIGAda Ada Letters (1999)

On September 30, 1998, the Ada Resource Association (ARA) accepted responsibility to continue the activities of the Ada Joint Program Office (AIPO), as part of transitioning Ada support from government to private industry. The ARA is promoting Ada in a variety of areas. One primary responsibility is the continuation of the Ada compiler validation process.The ARA considered it necessary to distance the vendors that comprise the ARA from the validation process itself. Consequently, the ARA is supporting the activities of the Ada Working Group (JTC1/SC22/WG9) within the International Organization for Standards (ISO) to standardize the existing validation processes. To become a standard, the Ada validation terminology must be changed to match ISO terminology (for example, validation is replaced with conformance assessment). The actual validation procedures supported by the ARA are largely unchanged from those under the AJPO, with a few minor changes to reduce bureaucracy, improve reproducibility, and more easily integrate language maintenance. A number of independent organizations will work together to perform and oversee validations.The revised procedures are in use while waiting for the actual ISO approval. To date, seven conformity assessments by two vendors have been performed using the new procedures and organization.
A new framework for debugging globally optimized code
Authors: Le-Chun Wu, Rajiv Mirani, Harish Patil, Bruce Olsen, Wen-mei W. Hwu
Venue: ACM SIGPLAN Notices (1999)

With an increasing number of executable binaries generated by optimizing compilers today, providing a clear and correct source-level debugger for programmers to debug optimized code has become a necessity. In this paper, a new framework for debugging globally optimized code is proposed. This framework consists of a new code location mapping scheme, a data location tracking scheme, and an emulation-based forward recovery model. By taking over the control early and emulating instructions selectively, the debugger can preserve and gather the required program state for the recovery of expected variable values at source breakpoints. The framework has been prototyped in the IMPACT compiler and GDB-4.16. Preliminary experiments conducted on several SPEC95 integer programs have yielded encouraging results. The extra time needed for the debugger to calculate the limits of the emulated region and to emulate instructions is hardly noticeable, while the increase in executable file size due to the extra debug information is on average 76% of that of the executable file with no debug information.
The role of IS personnel in Web-based systems development: the case of a health care organization
Authors: Cynthia Ruppel, James Konecny
Venue: Proceedings of the 2000 ACM SIGCPR conference on Computer personnel research (2000)

The development process of web-based systems has received little attention in the academic literature. It is not clear whether the traditional roles, methods and techniques currently used in traditional systems analysis and design are still relevant in the development of web-based systems. This research represents a case study of a health care organization which developed two web-based systems projects with different purposes, different development processes and different roles for IS personnel. Within this single organizational system the development of these two systems is explored and rationale for the differing roles of the IS personnel are suggested. Although both systems discussed are web-based systems, the role of the IS personnel, the impact on the IS department responsibilities and the participation of users are different.
Instructional interventions in computer-based tutoring: differential impact on learning time and accuracy
Authors: Albert Corbett, Holly Trask
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (2000)

We can reliably build &ldquo;second generation&rdquo; intelligent computer tutors that are approximately half as effective as human tutors. This paper evaluates two interface enhancements designed to improve the effectiveness of one successful second generation tutor, the ACT Programming Tutor. One enhancement employs animated feedback to make key data structure relationships salient. The second enhancement employs subgoal scaffolding to support students in developing simple programming plans. Both interventions were successful, but had very different impacts on student effort required to achieve mastery in the tutor environment and on subsequent posttest accuracy. These results represent a step forward in closing the gap between computer tutors and human tutors.
Using naming time to evaluate quality predictors for model simplification
Authors: Benjamin Watson, Alinda Friedman, Aaron McGaffey
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (2000)

Model simplification researchers require quality heuristics to guide simplification, and quality predictors to allow comparison of different simplification algorithms. However, there has been little evaluation of these heuristics or predictors. We present an evaluation of quality predictors. Our standard of comparison is naming time, a well established measure of recognition from cognitive psychology. Thirty participants named models of familiar objects at three levels of simplification. Results confirm that naming time is sensitive to model simplification. Correlations indicate that view-dependent image quality predictors are most effective for drastic simplifications, while view-independent three-dimensional predictors are better for more moderate simplifications.