ppxscal/embedding_network huggingface dataset:
Linearised Euclidean Shortening Flow of Curve Geometry
Authors: Alfons H. Salden, Bart M. Ter Haar Romeny, Max A. Viergever
Venue: International Journal of Computer Vision (1999)

The geometry of a space curve is described in terms of a Euclidean invariant frame field, metric, connection, torsion and curvature. Here the torsion and curvature of the connection quantify the curve geometry. In order to retain a stable and reproducible description of that geometry, such that it is slightly affected by non-uniform protrusions of the curve, a linearised Euclidean shortening flow is proposed. (Semi)-discretised versions of the flow subsequently physically realise a concise and exact (semi-)discrete curve geometry. Imposing special ordering relations the torsion and curvature in the curve geometry can be retrieved on a multi-scale basis not only for simply closed planar curves but also for open, branching, intersecting and space curves of non-trivial knot type. In the context of the shortening flows we revisit the maximum principle, the semi-group property and the comparison principle normally required in scale-space theories. We show that our linearised flow satisfies an adapted maximum principle, and that its Green&lsquo;s functions possess a semi-group property. We argue that the comparison principle in the case of knots can obstruct topological changes being in contradiction with the required curve simplification principle. Our linearised flow paradigm is not hampered by this drawback&semi; all non-symmetric knots tend to trivial ones being infinitely small circles in a plane. Finally, the differential and integral geometry of the multi-scale representation of the curve geometry under the flow is quantified by endowing the scale-space of curves with an appropriate connection, and calculating related torsion and curvature aspects. This multi-scale modern geometric analysis forms therewith an alternative for curve description methods based on entropy scale-space theories.
Configuration of Locally Spared Arrays in the Presence of Multiple Fault Types
Authors: Laurence E. LaForge
Venue: IEEE Transactions on Computers (1999)

The bulk of results for the performance of configuration architectures treat the case of failed processors, but neglect switches that are stuck open or closed. By contrast, the present work characterizes this multivariate problem in the presence of either iid or clustered faults. Suppose that the designer wishes to assure, with high probability, a fault free $s \times t$ array. If local sparing is used then, as we prove, the area of the redundant array is 1) $\Theta(st\; \log st)$ in the presence of faulty elements or faulty elements and switches stuck open; 2) $\Theta(st\; \log^2 st)$ in the presence of faulty elements and switches stuck closed; 3) $\Theta([st]^2\; \log st)$ in the presence of faulty elements and switches that may be either stuck open or stuck closed. We also furnish bounds on maximum wirelength and an optimal configuration algorithm.
Test Generation for Mixed-Signal Devices Using Signal Flow Graphs
Authors: Rajesh Ramadoss, Michael L. Bushnell
Venue: Journal of Electronic Testing: Theory and Applications (1999)

We describe a new reverse simulation approach to analog and mixed-signal circuit test generation that parallels digital test generation. We invert the analog circuit signal flow graph, reverse simulate it with good and bad machine outputs, and obtain test waveforms and component tolerances, given circuit output tolerances specified by the functional test needs of the designer. The inverted graph allows backtracing to justify analog outputs with analog input sinusoids. Mixed-signal circuits can be tested using this approach, and we present test generation results for two mixed-signal circuits and four analog circuits, one being a multiple-input, multiple-output circuit. This analog backtrace method can generate tests for second-order analog circuits and certain non-linear circuits. These cannot be handled by existing methods, which lack a fault model and a backtrace method. Our proposed method also defines the necessary tolerances on circuit structural components, in order to keep the output circuit signal within the envelope specified by the designer. This avoids the problem of overspecifying analog circuit component tolerances, and reduces cost. We prove that our parametric fault tests also detect all catastrophic faults. Unlike prior methods, ours is a structural, rather than functional, analog test generation method.
Convergence of a Crystalline Algorithm for the Motion of a Closed Convex Curve by a Power of Curvature $V=K^\alpha$
Authors: TaKeo K. Ushijima, Shigetoshi Yazaki
Venue: SIAM Journal on Numerical Analysis (1999)

A finite difference scheme is constructed for the evolution of a plane curve driven by a power of curvature: $V=K^\alpha$, $\alpha>0$, where V and K are the normal velocity and the curvature, respectively. Here we assume that the curve is closed, strictly convex, and immersed in the plane R2. This curve-evolution is discretized using a crystalline approximation which is a kind of finite difference scheme for the nonlinear evolution equation. We prove convergence of this scheme and show the rate of convergence. Moreover, some numerical examples are presented.
Plans for the TREC-9 web track
Authors: David Hawking
Venue: ACM SIGIR Forum (1999)

In recent years, TREC has broadened its scope to include many more facets of the Web searching process. In TREC-8 (1999), the Web special interest track evaluated link-based retrieval methods investigated differences between Web and traditional TREC ad hoc documents, and studied efficiency and effectiveness tradeoffs on large data sets. In addition, although neither used Web data, both the Cross-Lingual track and the Question amp; Answer track studied issues of considerable importance to everyday Web search.In TREC-9, the main Web track task will use a larger set of Web documents than last year and will use search topics derived from search engine logs. This task will be the closest approximation in TREC-9 to the traditional TREC Ad Hoc retrieval task.
Energy-driven integrated hardware-software optimizations using SimplePower
Authors: N. Vijaykrishnan, M. Kandemir, M. J. Irwin, H. S. Kim, W. Ye
Venue: ACM SIGARCH Computer Architecture News (2000)

With the emergence of a plethora of embedded and portable applications, energy dissipation has joined throughput, area, and accuracy/precision as a major design constraint. Thus, designers must be concerned with both optimizing and estimating the energy consumption of circuits, architectures, and software. Most of the research in energy optimization and/or estimation has focused on single components of the system and has not looked across the interacting spectrum of the hardware and software. The novelty of our new energy estimation framework, SimplePower, is that it evaluates the energy considering the system as a whole rather than just as a sum of parts, and that it concurrently supports both compiler and architectural experimentation. We present the design and use of the SimplePower framework that includes a transition-sensitive, cycle-accurate datapath energy model that interfaces with analytical and transition sensitive energy models for the memory and bus subsystems, respectively. We analyzed the energy consumption of ten codes from the multidimensional array domain, a domain that is important for embedded video and signal processing systems, after applying different compiler and architectural optimizations. Our experiments demonstrate that early estimates from the SimplePower energy estimation framework can help identify the system energy hotspots and enable architects and compiler designers to focus their efforts on these areas.
On the Approximate Cyclic Reduction Preconditioner
Authors: Arnold Reusken
Venue: SIAM Journal on Scientific Computing (1999)

We present a preconditioning method for the iterative solution of large sparse systems of equations. The preconditioner is based on ideas both from ILU preconditioning and from multigrid. The resulting preconditioning technique requires the matrix only. A multilevel structure is obtained by using maximal independent sets for graph coarsening. A Schur complement approximation is constructed using a sequence of point-Gaussian elimination steps. The resulting preconditioner has a transparent modular structure similar to the algorithmic structure of a multigrid V-cycle.
Performance optimization using separator sets
Authors: Yutaka Tamiya
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

In this paper, we propose a new method to optimize a performance of a very large circuit. We find the best set of local transformations to be applied to the circuit, by inserting &ldquo;padding nodes&rdquo; on non-critical edges of the circuit, and calculating separator sets of the circuit using separator sets. Our method is robust for very large circuits, because its memory usage and calculation time are linear and polynomial order with the size of the circuit.According to our experimental results, our method has accomplished all circuits, while K. J. Singh's selection function method has aborted with three large circuits because of memory overflow. The results also shows our method has a comparable capability in delay optimization to Singh's method.
Video helps remote work: speakers who need to negotiate common ground benefit from seeing each other
Authors: Elizabeth S. Veinott, Judith Olson, Gary M. Olson Xiaolan Fu
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

More and more organizations are forming teams that are not co-located. These teams communicate via email, fax, telephone and audio conferences, and sometimes video. The question often arises whether the cost of video is worth it. Previous research has shown that video makes people more satisfied with the work, but it doesnt help the quality of the work itself. There is one exception; negotiation tasks are measurably better with video. In this study, we show that the same effect holds for a more subtle form of negotiation, when people have to negotiate meaning in a conversation. We compared the performance and communication of people explaining a map route to each other. Half the pairs have video and audio connections, half only audio. Half of the pairs were native speakers of English; the other half were non-native speakers, those presumably who have to negotiate meaning more. The results showed that non-native speaker pairs did benefit from the video; native speakers did not. Detailed analysis of the conversational strategies showed that with video, the non-native speaker pairs spent proportionately more effort negotiating common ground.
Cell replication and redundancy elimination during placement for cycle time optimization
Authors: Ingmar Neumann, Dominik Stoffel, Hendrik Hartje, Wolfgang Kunz
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

This paper presents a new timing driven approach for cell replication tailored to the practical needs of standard cell layout design. Cell replication methods have been studied extensively in the context of generic partitioning problems. However, until now it has remained unclear what practical benefit can be obtained from this concept in a realistic environment for timing driven layout synthesis. Therefore, this paper presents a timing driven cell replication procedure, demonstrates its incorporation into a standard cell placement and routing tool and examines its benefit on the final circuit performance in comparison with conventional gate or transistor sizing techniques. Furthermore, we demonstrate that cell replication can deteriorate the stuck-at fault testability of circuits and show that stuck-at redundancy elimination must be integrated into the placement procedure. Experimental results demonstrate the usefulness of the proposed methodology and suggest that cell replication should be an integral part of the physical design flow complementing traditional gate sizing techniques.
Assessing and enhancing software testing effectiveness
Venue: ACM SIGSOFT Software Engineering Notes (2000)

Although many techniques for testing software have been proposed over the last twenty years, there is still not enough solid evidence to indicate which (if any) of these techniques are effective. It is difficult to perform meaningful comparisons of the cost and effectiveness of testing techniques; in fact, even defining these terms in a meaningful way is problematic. Consider an erroneous program P, its specification S, and a test data adequacy criterion C (such as 100% branch coverage). Even if we restrict the size of the test sets to be considered, there are a huge number of different test sets that satisfy criterion C for P and S. Since these adequate test sets typically have different properties, in order to investigate effectiveness (or other properties) rigorously, the entire space of test sets must be considered (according to some reasonable probability distribution) and appropriate probabilistic analysis and/or statistical sampling techniques must be used.In earlier research, supported by NSF Grant CCR-9206910, we developed analytical tools and an experiment design to address these issues and applied them to comparing a number of well-known testing techniques. The primary measure of effectiveness considered was probability that an adequate test set would detect at least one fault and the most of the experiment subjects were fairly small. The main thread of this research project extends that work in several directions: additional measures of cost and effectiveness are considered, analytical and experimental tools are developed for these measures, and experiments are conducted on larger programs.
Superlinear Convergence of a Stabilized SQP Method to a Degenerate Solution
Authors: Stephen J. Wright
Venue: Computational Optimization and Applications (1998)

We describe a slight modification of the well-known sequential quadratic programming method for nonlinear programming that attains superlinear convergence to a primal-dual solution even when the Jacobian of the active constraints is rank deficient at the solution. We show that rapid convergence occurs even in the presence of the roundoff errors that are introduced when the algorithm is implemented in floating-point arithmetic.
Optimum loading dispersion for high-speed tree-type decision circuitry
Authors: Jie-Hong Roland Jiang
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

With increasing density and capacity due to technology scaling, augmenting data (especially in semiconductor memories) burden selection circuitry with exponentially growing capacitive loads. This tendency violates stringent timing requirements.This work ameliorates the situation for k-stage tree-type decision circuitry. We show that for a k-stage binary decision tree, there always exists an optimum solution such that, after the select-signal arrangement, the worst case loading among select signals equals a lower bound. Our proposed procedure not only provides an optimum solution but also minimizes the loading variance. The worst case loading can be reduced up to nearly k/2 times, thus speeding up and saving power up to k/2 times or so for the select signal with the heaviest loading. In contrast, excluding one unit-loading select signal, the empirical variance of the remaining (k - 1) signals is always less than 1 instead of diverging. Hence, our approach, for timing-driven layout synthesis, is competent to design high-performance tree-type decision circuitry with more accurate timing and power prediction. In addition, by the presented approach, we can have the alternative of optimizing either for k-stage or for (k-1)-stage, meanwhile possibly minimizing the other. Our algorithm, also, can easily be extended for a general k-stage decision tree with r descendants per node, not restricted to a binary tree; the resultant worst case loading could be quite close to the lower bound and reduced up to nearly k(r - 1)/r times.
Boundary Treatments for Multilevel Methods on Unstructured Meshes
Authors: Tony F. Chan, Susie Go, Jun Zou
Venue: SIAM Journal on Scientific Computing (1999)

In applying multilevel iterative methods on unstructured meshes, the grid hierarchy can allow general coarse grids whose boundaries may be nonmatching to the boundary of the fine grid. In this case, the standard coarse-to-fine grid transfer operators with linear interpolants are not accurate enough at Neumann boundaries so special care is needed to correctly handle different types of boundary conditions. We propose two effective ways to adapt the standard coarse-to-fine interpolations to correctly implement boundary conditions for two-dimensional polygonal domains, and we provide some numerical examples of multilevel Schwarz methods (and multigrid methods) which show that these methods are as efficient as in the structured case. In addition, we prove that the proposed interpolants possess the local optimal L2-approximation and H1-stability, which are essential in the convergence analysis of the multilevel Schwarz methods. Using these results, we give a condition number bound for two-level Schwarz methods.
Excentric labeling: dynamic neighborhood labeling for data visualization
Authors: Jean-Daniel Fekete, Catherine Plaisant
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

The widespread use of information visualization is hampered by the lack of effective labeling techniques. An informal taxonomy of labeling methods is proposed. We then describe excentric labeling, a new dynamic technique to label a neighborhood of objects located around the cursor. This technique does not intrude into the existing interaction, it is not computationally intensive, and was easily applied to several visualization applications. A pilot study with eight subjects indicates a strong speed benefit over a zoom interface for tasks that involve the exploration of large numbers of objects. Observations and comments from users are presented.
Asynchronous Parallel Simulation of Parallel Programs
Authors: Sundeep Prakash, Ewa Deelman, Rajive Bagrodia
Venue: IEEE Transactions on Software Engineering (2000)

Parallel simulation of parallel programs for large datasets has been shown to offer significant reduction in the execution time of many discrete event models. This paper describes the design and implementation of MPI-SIM, a library for the execution driven parallel simulation of task and data parallel programs. MPI-SIM can be used to predict the performance of $existing$ programs written using MPI for message-passing, or written in UC, a data parallel language, compiled to use message-passing. The simulation models can be executed sequentially or in parallel. Parallel execution of the models are synchronized using a set of asynchronous conservative protocols. This paper demonstrates how protocol performance is improved by the use of application-level, runtime analysis. The analysis targets the communication patterns of the application. We show the application-level analysis for message passing and data parallel languages. We present the validation and performance results for the simulator for a set of applications that include the NAS Parallel Benchmark suite. The application-level optimization described in this paper yielded significant performance improvements in the simulation of parallel programs, and in some cases completely eliminated the synchronizations in the parallel execution of the simulation model.
Preconditioned Mixed Spectral Element Methods for Elasticity and Stokes Problems
Authors: Luca F. Pavarino
Venue: SIAM Journal on Scientific Computing (1998)

This paper continues our study of efficient preconditioners for the indefinite systems obtained by discretizing the linear elasticity and Stokes problems with mixed spectral methods in three dimensions. Our study is extended here in two new directions, to include i) more general (multidomain) mixed spectral element methods and ii) a new class of block-triangular preconditioners. The stiffness matrices resulting from Stokes and mixed elasticity problems have the structure of saddle point problems with a penalty term, which is associated with the Poisson ratio for elasticity problems or with stabilization techniques for Stokes problems. The main result of this paper shows that the convergence rate of the proposed preconditioned iterative methods is independent of the penalty parameter $\nu$, the number of spectral elements N, and mildly dependent on the spectral degree n via the inf-sup constant. The number of iterations required by the block-triangular preconditioner is much smaller than the one required by the block-diagonal preconditioner. On the other hand, the block-triangular preconditioner is no longer symmetric and has a small extra cost. These results and several numerical experiments presented in the final section show that these algorithms are a practical and efficient strategy for the iterative solution of the indefinite systems arising from mixed spectral element discretizations of elliptic systems.
The WarpEngine: an architecture for the post-polygonal age
Authors: Voicu Popescu, John Eyles, Anselmo Lastra, Joshua Steinhurst, Nick England, Lars Nyland
Venue: Proceedings of the 27th annual conference on Computer graphics and interactive techniques (2000)

We present the WarpEngine, an architecture designed for real-time imaged-based rendering of natural scenes from arbitrary viewpoints. The modeling primitives are real-world images with per-pixel depth. Currently they are acquired and stored off-line; in the near future real-time depth-image acquisition will be possible, the WarpEngine is designed to render in immediate mode from such data sources. The depth-image resolution is locally adapted by interpolation to match the resolution of the output image. 3D warping can occur either before or after the interpolation; the resulting warped/interpolated samples are forward-mapped into a warp buffer, with the precise locations recorded using an offset. Warping processors are integrated on-chip with the warp buffer, allowing efficient, scalable implementation of very high performance systems. Each chip will be able to process 100 million samples per second and provide 4.8GigaBytes per second of bandwidth to the warp buffer. The WarpEngine is significantly less complex than our previous efforts, incorporating only a single ASIC design. Small configurations can be packaged as a PC add-in card, while larger deskside configurations will provide HDTV resolutions at 50 Hz, enabling radical new applications such as 3D television. WarpEngine will be highly programmable, facilitating use as a test-bed for experimental IBR algorithms.
ACOM (&ldquo;computing for all&rdquo;): an integrated approach to the teaching and learning of information technology
Authors: Hannah Dee, Peter Reffell
Venue: ACM SIGCSE Bulletin (1999)

This poster describes the ACOM modules at Leeds University, teaching IT skills to a very large and diverse student body.
Biotransport in the human respiratory system
Authors: David Elad
Venue: Technology and Health Care (1999)

The human respiratory system is an 'open' organ, which is designed to exchange oxygen and carbon dioxide between the circulating blood and the external environment. This gas exchange is successfully accomplished via a set of transport phenomena comprised of oscillatory air flow, heat and water vapor exchange, mucus transport and air-blood gas exchange all of which take place in a complex geometry that undergoes large changes. These transport phenomena occur simultaneously to supply the body's need for oxygen in different physiological conditions and/or environments, while defending it from external hazards. The need for better comprehension of the mechanisms involved in pulmonary diseases and for advanced techniques for both diagnosis and intervention stimulated numerous studies of the different biotransport processes that take place in the human respiratory system.