ppxscal/embedding_network huggingface dataset:
A 16 &times; 16 Cellular Neural Network UniversalChip: The First Complete Single-Chip Dynamic Computer Array withDistributed Memory and with Gray-Scale Input-Output
Authors: J. M. Cruz, L. O. Chua
Venue: Analog Integrated Circuits and Signal Processing (1998)

This paper presents a 16 &times; 16 Cellular Neural Network Universal Chip with analog input and output ports, which can read in and process gray-scale images in the analog domain. The chip contains about 5,000 analog multipliers and has been fabricated in a 0.8 &micro;m CMOS process.
Time--Space Tradeoffs For Undirected st-Connectivity on a Graph Automata
Authors: Jeff A. Edmonds
Venue: SIAM Journal on Computing (1998)

Undirected st-connectivity is an important problem in computing. There are algorithms for this problem that use O(n) time and ones that use O(log n) space. The main result of this paper is that, in a very natural structured model, these upper bounds are not simultaneously achievable. Any probabilistic jumping automaton for graphs (JAG) requires either space $\Omega( \log^2 n / \log log n )$ or time $n^{(1 + \Omega ( 1 / \log \log n )) }$ to solve undirected st-connectivity.
Regularization by Truncated Total Least Squares
Authors: R. D. Fierro, G. H. Golub, P. C. Hansen, D. P. O'Leary
Venue: SIAM Journal on Scientific Computing (1997)

The total least squares (TLS) method is a successful method for noise reduction in linear least squares problems in a number of applications. The TLS method is suited to problems in which both the coefficient matrix and the right-hand side are not precisely known. This paper focuses on the use of TLS for solving problems with very ill-conditioned coefficient matrices whose singular values decay gradually (so-called discrete ill-posed problems), where some regularization is necessary to stabilize the computed solution. We filter the solution by truncating the small singular values of the TLS matrix. We express our results in terms of the singular value decomposition (SVD) of the coefficient matrix rather than the augmented matrix. This leads to insight into the filtering properties of the truncated TLS method as compared to regularized least squares solutions. In addition, we propose and test an iterative algorithm based on Lanczos bidiagonalization for computing truncated TLS solutions.
A New Lagrangian Relaxation Based Algorithm for a Class ofMultidimensional Assignment Problems
Authors: Aubrey B. Poore, Alexander J. Robertson,  III
Venue: Computational Optimization and Applications (1997)

Large classes of data association problems in multiple target tracking applications involving both multiple and single sensor systems can be formulated as multidimensional assignment problems. These NP-hard problems are large scale and sparse with noisy objective function values, but must be solved in &ldquo;real-time&rdquo;. Lagrangian relaxation methods have proven to be particularly effective in solving these problems to the noise level in real-time, especially for dense scenarios and for multiple scans of data from multiple sensors. This work presents a new class of constructive Lagrangian relaxation algorithms that circumvent some of the deficiencies of previous methods. The results of several numerical studies demonstrate the efficiency and effectiveness of the new algorithm class.
Dynamics and Approximations of a Velocity Tracking Problem for the Navier--Stokes Flows with Piecewise Distributed Controls
Authors: L. S. Hou, Y. Yan
Venue: SIAM Journal on Control and Optimization (1997)

We study the dynamics of a piecewise (in time) distributed optimal control problem for the Navier--Stokes equations which models velocity tracking over time. We also study the dynamics of semidiscrete and fully discrete approximations of this velocity tracking problem. We prove that the rates of velocity tracking are exponential. Some computational results are presented, which reinforces the theoretical results derived.
The Conceptual-Level Design Approach to Complex Systems
Authors: David B. Lidsky, Jan M. Rabaey
Venue: Journal of VLSI Signal Processing Systems (1998)

The increasing complexity and heterogeneity of current-day systems makes early design trade-offs and analysis a necessity. Typically such exploration is performed at a time that specifications are incomplete or ill-defined, and no behavioral or structural descriptions have been formulated. The only information available are properties of the system and its components, such as abstract functionality, complexity, constraints and cost functions.In present design practice, this level of abstraction, henceforth called the conceptual-level, is addressed in an ad-hoc fashion without much support from tools or without utilizing existing data and models.This paper proposes a methodology and framework to support conceptual-level design. It consists of a distributed data modeling environment combined with a set of appropriate user interfaces.
Computing Hopf Bifurcations I
Authors: John Guckenheimer, Mark Myers, Bernd Sturmfels
Venue: SIAM Journal on Numerical Analysis (1997)

This paper addresses the problems of detecting Hopf bifurcations in systems of ordinary differential equations and following curves of Hopf points in two-parameter families of vector fields. The established approach to this problem relies upon augmenting the equilibrium condition so that a Hopf bifurcation occurs at an isolated, regular point of the extended system. We propose two new methods of this type based on classical algebraic results regarding the roots of polynomial equations and properties of Kronecker products for matrices. In addition to their utility as augmented systems for use with standard Newton-type continuation methods, they are also particularly well adapted for solution by computer algebra techniques for vector fields of small or moderate dimension.
Multilevel circuit partitioning
Authors: Charles J. Alpert, Jen-Hsin Huang, Andrew B. Kahng
Venue: Proceedings of the 34th annual Design Automation Conference (1997)

Recent work has illustrated the promise ofmultilevel approaches for partitioning large circuits. Multilevel partitioningrecursively clusters the instance until its size is smallerthan a given threshold, then unclusters the instance while applyinga partitioning refinement algorithm. Our multilevel partitioner usesa new technique to control the number of levels in the matching-basedclustering phase and also exploits recent innovations in classiciterative partitioning. Our heuristic outperforms numerousexisting bipartitioning heuristics, with improvements rangingfrom 6.9 to 27.9% for 100 runs and 3.0 to 20.6% for just 10 runs(while also using less CPU time).
3D Surface Estimation and Model Construction From Specular Motion in Image Sequences
Authors: Jiang Yu Zheng, Yoshihiro Fukagawa, Norihiro Abe
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1997)

This work reconstructs a 3D graphics model of an object with specular surfaces by its rotation. Continuous images are taken to measure highlights on the smooth surfaces and their motion. Coplanar extended lights determine a plane of rays to produce a highlight stripe on the object. 3D surfaces are then recovered from the moving stripe. We investigate global motion characteristics of the highlights in the Epipolar-plane images so as to qualitatively identify surface types and control the modeling process. Under single and multiple plane-of-rays illuminations, we give two quantitative approaches for surface and normal recovery which use highlight orientation in the image and highlight motion in the Epipolar-Plane images. The computations employ a first-order differential equation and linear equations, respectively.
Future computing environments for DA (panel)
Authors: Andrew Rappaport
Venue: Proceedings of the 25th ACM/IEEE Design Automation Conference (1988)

With the advent of 10MIPS workstations, and 50MIPS workstations promised in two years, what will the next generation engineering computing environment look like, five years from now? Will all the workstations use the same architecture? SPARC? MIPS? AMD? VAX? Does it matter? Will all CAD tools run on a 10MIPS, $1,000 Personal Computer? Will the term 'mainframe' become obsolete? What operating systems will be used? What languages will tools be written in? C++? Smalltalk? Common Loops? What is the role of software standards? UNIX? X-Windows? PostScript? Will 'C' ever be standardized? What about software development environments - what will they look like? How much will parallel, general-purpose computing be used? How much performance will be available from parallel computers? Is 'massively parallel' computing the answer or will 'conventional' multiprocessors provide better price-performance? What will be the role of hardware accelerators; will they be needed at all? How will high-speed networks figure in this system and how fast do they have to be? Will the Ethernet cables just installed be sufficient or will they need to be replaced again?
A multimedia C programming course that supports different learning situations (poster)
Authors: Simon Moore, Martyn Spink
Venue: ACM SIGCSE Bulletin (1998)

A colour-coded framework for organising material in a multimedia C programming course is described. Together with maps of the 'solar-system' of material, the framework allows users to choose a variety of routes through the material. This allows students to tailor the course to their needs.
Sampling procedural shaders using affine arithmetic
Authors: Wolfgang Heidrich, Philipp Slusallek, Hans-Peter Seidel
Venue: ACM Transactions on Graphics (TOG) (1998)

Procedural shaders have become popular tools for describing surface reflectance functions and other material properties. In comparison to fixed resolution textures, they have the advantage of being resolution-independent and storage-efficient.While procedural shaders provide an interface for evaluating the shader at a single point, it is not easily possible to obtain an average value of the shader together with accurate error bounds over a finite area. Yet the ability to compute such error bounds is crucial for several interesting applications, most notably heirarchical area sampling for global illumination, using the finite element approach, and for generation of textures used in interactive computer graphics.Using affine arithmetic for evaluating the shader over a finite area yields a tight, conservative error interval for the shader function. Compilers can automatically generate code for utilizing affine arithmetic from within shaders implemented in a dedicated language such as the RenderMann shading language.
Core-stateless fair queueing: achieving approximately fair bandwidth allocations in high speed networks
Authors: Ion Stoica, Scott Shenker, Hui Zhang
Venue: ACM SIGCOMM Computer Communication Review (1998)

Router mechanisms designed to achieve fair bandwidth allocations, like Fair Queueing, have many desirable properties for congestion control in the Internet. However, such mechanisms usually need to maintain state, manage buffers, and/or perform packet scheduling on a per flow basis, and this complexity may prevent them from being cost-effectively implemented and widely deployed. In this paper, we propose an architecture that significantly reduces this implementation complexity yet still achieves approximately fair bandwidth allocations. We apply this approach to an island of routers --- that is, a contiguous region of the network --- and we distinguish between edge routers and core routers. Edge routers maintain per flow state; they estimate the incoming rate of each flow and insert a label into each packet header based on this estimate. Core routers maintain no per flow state; they use FIFO packet scheduling augmented by a probabilistic dropping algorithm that uses the packet labels and an estimate of the aggregate traffic at the router. We call the scheme Core-Stateless Fair Queueing. We present simulations and analysis on the performance of this approach, and discuss an alternate approach.
User-oriented document clustering: a framework for learning in information retrieval
Authors: J. S. Deogun, V. V. Raghavan
Venue: Proceedings of the 9th annual international ACM SIGIR conference on Research and development in information retrieval (1986)

In information retrieval, cluster analysis is an important tool employed to enhance both efficiency and effectiveness of the retrieval process. Most clustering algorithms have difficulty in reflecting the closeness of documents as perceived by the user. A two phase scheme for document clustering, whose results reflect the &ldquo;conceptual&rdquo; clusters that are perceived by the user of the retrieval system, is proposed. Since the clusters obtained by this scheme are not characterized in terms of the document representations, a strategy for cluster searching is also developed. Both the proposed document clustering scheme and document searching strategy are experimentally evaluated using a test collection from the SMART system. The preliminary experimental results obtained are very encouraging.
Adaptive Morphological Representation of Signals: Polynomialand Wavelet Methods
Authors: Hyungtai Cha, Luis F. Chaparro
Venue: Multidimensional Systems and Signal Processing (1997)

In this paper, we propose a novel signal representation based on mathematical morphology, and with it develop representations analogous to the polynomial transform and the bank-of-filters implementation of the wavelet representation. The geometric decomposition of a signal is achieved by separating it into analysis frames and applying mathematical morphological operators with adaptive structuring functions to each frame. The adaptation parameters are found by solving iteratively nonlinear equations that result from constraining the morphological results to achieve optimal fitting. If the structuring functions are derived from real-valued orthogonal polynomials defined on a window, the representation is analogous to the polynomial transform. Using a morphological interpolation, we derive a pyramid-like structure to decompose a signal into gross and fine information components, at different scales, just as in the wavelet transformation. Non-linear morphological operators reduce the computational complexity of the proposed representations. Although these representations are easily extended to two-dimensions, one needs to consider the non&ndash;unique ordering of the structuring functions, and the different sampling, decimation and interpolation procedures in two-dimensions. The application of our procedures is mainly in image data compression, but they could also used in object identification. We illustrate our representations by means of one- and two-dimensional examples.
Generating Low-Degree 2-Spanners
Authors: Guy Kortsarz, David Peleg
Venue: SIAM Journal on Computing (1998)

A k-spanner of a connected (undirected unweighted) graph G=(V,E) is a subgraph G' consisting of all the vertices of V and a subset of the edges, with the additional property that the distance between any two vertices in G' is larger than that distance in G by no more than a factor of k. This paper is concerned with approximating the problem of finding a 2-spanner in a given graph, with minimum maximum degree. We first show that the problem is at least as hard to approximate as set cover. Then a randomized approximation algorithm is provided for this problem, with approximation ratio of $\tilde O(\Delta^{1/4})$. We then present a probabilistic algorithm that is more efficient for sparse graphs. Our algorithms are converted into deterministic ones using derandomization.
Exact analysis of Dodgson elections: Lewis Carroll's 1876 voting system is complete for parallel access to NP
Authors: Edith Hemaspaandra, Lane A. Hemaspaandra, Jörg Rothe
Venue: Journal of the ACM (JACM) (1997)

In 1876, Lewis Carroll proposed a voting system in which the winner is the candidate who with the fewest changes in voters' preferences becomes a Condorcet winner&mdash;a candidate who beats all other candidates in pairwise majority-rule elections. Bartholdi, Tovey, and Trick provided a lower bound&mdash;NP-hardness&mdash;on the computational complexity of determining the election winner in Carroll's system. We provide a stronger lower bound and an upper bound that matches our lower bound. In particular, determining the winner in Carroll's system is complete for parallel access to NP, that is, it is complete for Theta_2p for which it becomes the most natural complete problem known. It follows that determining the winner in Carroll's elections is not NP-complete unless the polynomial hierarchy collapses.
Optimal Registration of Object Views Using Range Data
Authors: Chitra Dorai, John Weng, Anil K. Jain
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1997)

This paper deals with robust registration of object views in the presence of uncertainties and noise in depth data. Errors in registration of multiple views of a 3D object severely affect view integration during automatic construction of object models. We derive a minimum variance estimator (MVE) for computing the view transformation parameters accurately from range data of two views of a 3D object. The results of our experiments show that view transformation estimates obtained using MVE are significantly more accurate than those computed with an unweighted error criterion for registration.
Optimization of the background memory utilization by partitioning
Authors: Uwe Eckhardt, Renate Merker
Venue: Proceedings of the 10th international symposium on System synthesis (1997)

The skillful utilization of the memory structure of a processor and of its background memory may crucially affect the system performance. We propose a restructuring of for-loop programs by hierarchical partitioning which improves the properties of the algorithm with respect to the memory utilization. We consider the problem for regularly connected processor arrays (where single processors are a special case) and for a memory structure which is subdivided into local foreground memory (register) and background memory with up to three levels (cache, RAM, mass storage). The extension of the lifetime of a variable on an inner memory level, i.e. the decrease of the number of read accesses to more outer memory levels is the object of the proposed method.
Prediction of Chaotic Time-Series with a Resource-Allocating RBF Network
Authors: Roman Rosipal, Miloš Koska, Igor Farkaš
Venue: Neural Processing Letters (1998)

One of the main problems associated with artificial neural networks on-line learning methods is the estimation of model order. In this paper, we report about a new approach to constructing a resource-allocating radial basis function network exploiting weights adaptation using recursive least-squares technique based on Givens QR decomposition. Further, we study the performance of pruning strategy we introduced to obtain the same prediction accuracy of the network with lower model order. The proposed methods were tested on the task of Mackey-Glass time-series prediction. Order of resulting networks and their prediction performance were superior to those previously reported by Platt [12].
Average and Worst Case Number of Nodes in Decision Diagrams of Symmetric Multiple-Valued Functions
Authors: Jon T. Butler, David S. Herscovici, Tsutomu Sasao, Robert J. Barton,  III
Venue: IEEE Transactions on Computers (1997)

We derive the average and worst case number of nodes in decision diagrams of r-valued symmetric functions of n variables. We show that, for large n, both numbers approach ${\textstyle{{{n^r} \over {r\,!}}}}.$ For binary decision diagrams (r = 2), we compute the distribution of the number of functions on n variables with a specified number of nodes. Subclasses of symmetric functions appear as features in this distribution. For example, voting functions are noted as having an average of ${\textstyle{n^2} \over 6}$ nodes, for large n, compared to ${\textstyle{{{n^2} \over 2}}},$ for general binary symmetric functions.
Multi-stage programming with explicit annotations
Authors: Walid Taha, Tim Sheard
Venue: ACM SIGPLAN Notices (1997)

We introduce MetaML, a statically-typed multi-stage programming language extending Nielson and Nielson's two stage notation to an arbitrary number of stages. MetaML extends previous work by introducing four distinct staging annotations which generalize those published previously [25, 12, 7, 6]We give a static semantics in which type checking is done once and for all before the first stage, and a dynamic semantics which introduces a new concept of cross-stage persistence, which requires that variables available in any stage are also available in all future stages.We illustrate that staging is a manual form of binding time analysis. We explain why, even in the presence of automatic binding time analysis, explicit annotations are useful, especially for programs with more than two stages.A thesis of this paper is that multi-stage languages are useful as programming languages in their own right, and should support features that make it possible for programmers to write staged computations without significantly changing their normal programming style. To illustrate this we provide a simple three stage example, and an extended two-stage example elaborating a number of practical issues.
Bounding of performance measures for a threshold-based queueing system with hysteresis
Authors: Leana Golubchik, John C. S. Lui
Venue: ACM SIGMETRICS Performance Evaluation Review (1997)

In this paper, we consider a K-server threshold-based queueing system with hysteresis in which the number of servers, employed for servicing customers, is governed by a forward threshold vector F= (F1, F2, hellip;, FK-1) (where F1 lt; F2 lt; hellip; lt; FK-1) and a reverse threshold vector R= (R1, R2, hellip;, RK-1) (where R1 lt; R2 lt; hellip; lt; RK-1). There are many applications where a threshold-based queueing system can be of great use. The main motivation for using a threshold-based approach in such applications is that they incur significant server setup, usage, and removal costs. And, as in most practical situations, an important concern is not only the system performance but rather its cost/performance ratio. The motivation for use of hysteresis is to control the cost during momentary fluctuations in workload. An important and distinguishing characteristic of our work is that in our model we consider the time to add a server to be non-negligible. This is a more accurate model, for many applications, than previously considered in other works. Our main goal in this work is to develop an efficient method for computing the steady state probabilities of a multi-server threshold queueing system with hysteresis, which will, in turn, allow computation of various performance measures.
Utilizing symmetry when model-checking under fairness assumptions: an automata-theoretic approach
Authors: E. A. Emerson, A. P. Sistla
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1997)

One useful technique for combating the state explosion problem is to exploit symmetry when performing temporal logic model checking. In previous work it is shown how, using some basic notions of group theory, symmetry may be exploited for the full range of correctness properties expressible in the very expressive temporal logic CTL*. Surprisingly, while fairness properties are readily expressible in CTL*, these methods are not powerful enough to admit any amelioration of state explosion, when fairness assumptions are involved. We show that it is nonetheless possible to handle fairness efficiently by trading some group theory for automata theory. Our automata-theoretic approach depends on detecting fair paths subtly encoded in a quotient structure whose arcs are annotated with permutations, by using a threaded structure that reflects coordinate shifts caused by the permutations.