ppxscal/embedding_network huggingface dataset:
Direct synthesis of timed asynchronous circuits
Authors: Sung Tae Jung, Chris J. Myers
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

This paper presents a new method to synthesize timed asynchronous circuits directly from the specification without generating a state graph. The synthesis procedure begins with a deterministic graph specification with timing constraints. A timing analysis extracts the timed concurrency and timed causality relations between any two signal transitions. Then, a hazard-free implementation of the specification is synthesized by analyzing precedence graphs which are constructed by using the timed concurrency and timed causality relations. The major result of this work is that the method does not suffer from the state explosion problem, achieves significant reductions in synthesis time, and generates synthesized circuits that have nearly the same area as compared to previous timed circuit methods. In particular, this paper shows that a timed circuit &mdash; not containing circuit hazards under given timing constraints &mdash; can be found by using the relations between signal transitions of the specification. Moreover, the relations can be efficiently found using a heuristic timing analysis algorithm. By allowing significantly larger designs to be synthesized, this work is a step towards the development of high-level synthesis tools for system level asynchronous circuits.
Abelian Difference Sets Without Self-conjugacy
Authors: K. T. Arasu, S. L. Ma
Venue: Designs, Codes and Cryptography (1998)

We obtain some results that are useful to the study of abelian difference sets and relative difference sets in cases where the self-conjugacy assumption does not hold. As applications we investigate McFarland difference sets, which have parameters of the form v=q^d+1\left( q^d+ q^d-1 +\cdots + q+2\right) ,k=q^d\left( q^d+q^d-1+\cdots +q+1\right) , \lambda = q^d \left( q^{d-1}+q^{d-2}+\cdots +q+1\right) , where q is a prime power andd a positive integer. Using our results, we characterize those abelian groups that admit a McFarland difference set of order k-\lambda =81. We show that the Sylow 3-subgroup of the underlying abelian group must be elementary abelian. Our results fill two missing entries in Kopilovich&lsquo;s table with answer &rsquo;&rsquo;no&lsquo;&lsquo;.
Visual profiles: a critical component of universal access
Authors: Julie A. Jacko, Max A. Dixon, Robert H. Rosa,  Jr., Ingrid U. Scott, Charles J. Pappas
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

This research focuses on characterizing visually impaired computer users performance on graphical user interfaces by linking clinical assessments of low vision with visual icon identification. This was accomplished by evaluating user performance on basic identification and selection tasks within a graphical user interface, comparing partially sighted user performance with fully sighted user performance, and linking task performance to specific profiles of visual impairment. Results indicate that visual acuity, contrast sensitivity, visual field and color perception were significant predictors of task performance. In addition, icon size and background color significantly influenced performance. Suggestions for future research are provided. Keywords
Classroom Note: The Power of a Matrix
Authors: M. Kwapisz
Venue: SIAM Review (1998)

In this note an elementary method of calculating any power of a given matrix is described. The method is quite similar to that presented by I. E. Leonard [SIAM Rev., 38 (1996), pp. 507--512].
Synchronizing a database to improve freshness
Authors: Junghoo Cho, Hector Garcia-Molina
Venue: ACM SIGMOD Record (2000)

In this paper we study how to refresh a local copy of an autonomous data source to maintain the copy up-to-date. As the size of the data grows, it becomes more difficult to maintain the copy \ fresh, &ldquo;making it crucial to synchronize the copy effectively. We define two freshness metrics, change models of the underlying data, and synchronization policies. We analytically study how effective the various policies are. We also experimentally verify our analysis, based on data collected from 270 web sites for more than 4 months, and we show that our new policy improves the \ freshness&rdquo; very significantly compared to current policies in use.
Coming to the wrong decision quickly: why awareness tools must be matched with appropriate tasks
Authors: Alberto Espinosa, Jonathan Cadiz, Luis Rico-Gutierrez, Robert Kraut, William Scherlis, Glenn Lautenbacher
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (2000)

This paper presents an awareness tool designed to help distributed, asynchronous groups solve problems quickly. Using a lab study, it was found that groups that used the awareness tool tended to converge and agree upon a solution more quickly. However, it was also found that individuals who did not use the awareness tool got closer to the correct solution. Implications for the design of awareness tools are discussed, with particular attention paid to the importance of matching the features of an awareness tool with a workgroup's tasks and goals.
Dissipativity and the Lur'e Problem for Parabolic Boundary Control Systems
Authors: L. Pandolfi
Venue: SIAM Journal on Control and Optimization (1998)

Dissipativity is studied for a class of boundary control systems whose free evolution is described by a holomorphic semigroup. It is proved that the system is dissipative if and only if there exists a (bounded selfadjoint) solution of the corresponding linear operator inequality. In addition, the Lur'e problem is solved under particular assumptions.
An efficient algorithm for finding a path subject to two additive constraints
Authors: Turgay Korkmaz, Marwan Krunz, Spyros Tragoudas
Venue: Proceedings of the 2000 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (2000)

One of the key issues in providing end-to-end quality-of-service guarantees in packet networks is how to determine a feasible route that satisfies a set of constraints while simultaneously maintaining high utilization of network resources. In general, finding a path subject to multiple additive constraints (e.g., delay, delay-jitter) is an NP-complete problem that cannot be exactly solved in polynomial time. Accordingly, heuristics and approximation algorithms are often used to address to this problem. Previously proposed algorithms suffer from either excessive computational cost or low performance. In this paper, we provide an efficient approximation algorithm for finding a path subject to two additive constraints. The worst-case computational complexity of this algorithm is within a logarithmic number of calls to Dijkstra's shortest path algorithm. Its average complexity is much lower than that, as demonstrated by simulation results. The performance of the proposed algorithm is justified via theoretical performance bounds. To achieve further performance improvement, several extensions to the basic algorithm are also provided at low extra computational cost. Extensive simulations are used to demonstrate the high performance of the proposed algorithm and to contrast it with other path selection algorithms.
Self-Organizing Maps and Learning Vector Quantization forFeature Sequences
Authors: Panu Somervuo, Teuvo Kohonen
Venue: Neural Processing Letters (1999)

The Self-Organizing Map (SOM) and Learning Vector Quantization (LVQ) algorithms are constructed in this work for variable-length and warped feature sequences. The novelty is to associate an entire feature vector sequence, instead of a single feature vector, as a model with each SOM node. Dynamic time warping is used to obtain time-normalized distances between sequences with different lengths. Starting with random initialization, ordered feature sequence maps then ensue, and Learning Vector Quantization can be used to fine tune the prototype sequences for optimal class separation. The resulting SOM models, the prototype sequences, can then be used for the recognition as well as synthesis of patterns. Good results have been obtained in speaker-independent speech recognition.
Making students read and review code
Authors: Andreas Zeller
Venue: ACM SIGCSE Bulletin (2000)

The Praktomat system allows students to read, review, and assess each other's programs in order to improve quality and style. After a successful submission, the student can retrieve and review a program of some fellow student selected by Praktomat. After the review is complete, the student may obtain reviews and re-submit improved versions of his program. The reviewing process is independent of grading; the risk of plagiarism is narrowed by personalized assignments and automatic testing of submitted programs. In a survey, more than two thirds of the students affirmed that reading each other's programs improved their program quality; this is also confirmed by statistical data.
H2 and \Hinf Design of Sampled-Data Systems Using Lifting. Part II: Properties of Systems in the Lifted Domain
Authors: Leonid Mirkin, Héctor P. Rotstein, Zalman J. Palmor
Venue: SIAM Journal on Control and Optimization (1999)

An important class of sampled-data systems becomes time-invariant when the systems are "lifted" into an appropriate domain. The purpose of the present paper is to study some basic properties of systems represented by state space equations in the lifted domain. Hidden modes, invariant zeros, and Riccati equations are investigated, and the connection between representations in continuous and lifted domains are clarified. The material treated here is important for solving optimal control problems of generalized sampled-data systems.
A classification of interdomain actions
Authors: Winifried E. Kühnhauser
Venue: ACM SIGOPS Operating Systems Review (1998)

This paper contributes to the recent discussion on unmet information security challenges for operating system designers. It focusses on the problem that in order to meet these challenges operating systems must be capable of supporting a multitude of information domains, each domain defined by its own and individual security policy. In such multi-domain systems, the interoperability between different information domains constitutes a major problem. While the security policies of the system control the interactions within their domains, it is an unsolved problem how interactions between different domains can be made secure.In order to provide a precise foundation for the discussion of secure interdomain actions as well as for the development of concepts for their implementation, the paper proposes a classification of interdomain actions that clearly identifies two major types of interdomain actions: interactions that cause conflicts between the involved security policies and interactions for which none of the involved policies can provide any security rule. The paper concludes that in order to support multiple information domains, operating systems must be capable of classifying interdomain actions, and they must support new types of interdomain security policies that mediate security conflicts in interdomain actions and complete the set of security rules for interdomain actions. The paper concludes with a discussion of the computational complexity of interdomain action classification.
Tangible progress: less is more in Somewire audio spaces
Authors: Andrew Singer, Debby Hindus, Lisa Stifelman, Sean White
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

We developed four widely different interfaces for users of Somewire, a prototype audio-only media space. We informally studied users experiences with the two screen- based interfaces. We prototyped a non-screen-based interface as an example of a novel tangible interface for a communication system. We explored the conflict between privacy and simplicity of representation, and identified two unresolved topics: the role of audio quality and the prospects for scsiling audio spaces beyond a single Workgroup. Finally, we formulated a set of design guidelines for control and representation in audio spaces, as follows: GUIs are not well-suited to audio spaces, users do not require control over localization or other audio attributes, and awareness of other users presence is desirable.
Efficient Sourcing and Debt Financing in Imperfect Product Markets
Authors: Venkat Subramaniam
Venue: Management Science (1998)

Supplier relations play an important role in determining a firm's product market strategy and position, by affecting the cost and quality of the product produced by the firm. These relations are especially significant because the cost of purchased materials for an average firm is more than half its total sales. In this paper, we model the adverse incentives of a firm that sources from a competitive supplier industry. We show that a firm's propensity to behave opportunistically towards its suppliers raises the firm's input costs by decreasing the number of suppliers servicing it. This results in a suboptimal production decision compared to the firm's first best choice. We argue that an appropriate level of debt financing alters the shareholder incentives and mitigates the hold-up problem. Further, we also show that at the optimal debt level, the firm produces its first best level of output.
41 is the Largest Size of a Cap in PG(4,4)
Authors: Yves Edel, Jürgen Bierbrauer
Venue: Designs, Codes and Cryptography (1999)

We settle the question of the maximal size of caps in PG(4,4), with the help of a computer program.
From Design Validation to Hardware Testing: A Unified Approach
Authors: Ghassan Al-Hayek, Chantal Robach
Venue: Journal of Electronic Testing: Theory and Applications (1999)

In this paper we propose a new approach that addresses both the problems of design validation and hardware testing since the early stages of the design flow. The approach consists in adapting the mutation testing, a software method, to circuits described in VHDL. At the functional level, the approach behaves as a design validation method and at the hardware level as a classical ATPG. Standard software test metrics are used for assessing the quality of the design validation process, and the hardware fault coverage for assessing the test quality at the hardware level. An enhancement process that allows design validation to be efficiently reused for hardware testing is detailed. The approach is shown to be efficient upon a set of representative circuits.
Measuring formal specification with &agr;-metric
Authors: Peter Kokol
Venue: ACM SIGSOFT Software Engineering Notes (1999)

This paper explains the use of alpha; - metrics in analysing and comparison of various formal specification languages.
Fault tolerant networks with small degree
Authors: Li Zhang
Venue: Proceedings of the twelfth annual ACM symposium on Parallel algorithms and architectures (2000)

In this paper, we study the design of fault tolerant networks for arrays and meshes by adding redundant nodes and edges. For a target graph G (linear array or mesh in this paper), a graph G&prime; is called a &kgr;-fault-tolerant graph of G if when we remove any &kgr; nodes from G&prime;, it still contains a subgraph isomorphic to G. The major quality measures for a fault-tolerant graph are the number of spare nodes it uses and the maximum degree it has. The degree is particularly important in practice as it poses constraints on the scalability of the system. In this paper, we aim at designing fault-tolerant graphs with both small degree and small number of spare nodes. The graphs we obtain have degree O(1) for arrays and O(log3 &kgr;) for meshes. The number of spare nodes used are O(&kgr; log2 &kgr;) and O(&kgr;2/log &kgr;), respectively. Compared to the previous results, the number of spare nodes used in our construction has one fewer linear factor in &kgr;.
Symbolic functional and timing verification of transistor-level circuits
Authors: Clayton B. McDonald, Randal E. Bryant
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

We introduce a new method of verifying the timing of custom CMOS circuits. Due to the exponential number of patterns required, traditional simulation methods are unable to exhaustively verify a medium-sized modern logic block. Static analysis can handle much larger circuits but is not robust with respect to variations from standard circuit structures. Our approach applies symbolic simulation to analyze a circuit over all input combinations without these limitations. We present a prototype simulator (SirSim) and experimental results. We also discuss using SirSim to verify an industrial design which previously required a special-purpose verification methodology.
Mind your vocabulary: query mapping across heterogeneous information sources
Authors: Chen-Chuan K. Chang, Héctor García-Molina
Venue: Proceedings of the 1999 ACM SIGMOD international conference on Management of data (1999)

In this paper we present a mechanism for translating constraint queries, i.e., Boolean expressions of constraints, across heterogeneous information sources. Integrating such systems is difficult in part because they use a wide range of constraints as the vocabulary for formulating queries. We describe algorithms that apply user-provided mapping rules to translate query constraints into ones that are understood and supported in another context, e.g., that use the proper operators and value formats. We show that the translated queries minimally subsume the original ones. Furthermore, the translated queries are also the most compact possible. Unlike other query mapping work, we effectively consider inter-dependencies among constraints, i.e., we handle constraints that cannot be translated independently. Furthermore, when constraints are not fully supported, our framework explores relaxations (semantic rewritings) into the closest supported version. Our most sophisticated algorithm (Algorithm TDQM) does not blindly convert queries to DNF (which would be easier to translate, but expensive); instead it performs a top-down mapping of a query tree, and does local query structure conversion only when necessary.
The Maximum Angle Condition for Mixed and Nonconforming Elements: Application to the Stokes Equations
Authors: Gabriel Acosta, Ricardo G. Durán
Venue: SIAM Journal on Numerical Analysis (1999)

For the Lagrange interpolation it is known that optimal order error estimates hold for elements satisfying the maximum angle condition. The objective of this paper is to obtain similar results for the Raviart--Thomas interpolation arising in the analysis of mixed methods. We prove that optimal order error estimates hold under the maximum angle condition for this interpolation both in two and three dimensions and, moreover, that this condition is indeed necessary to have these estimates. Error estimates for the mixed approximation of second order elliptic problems and for the nonconforming piecewise linear approximation of the Stokes equations are derived from our results.
VC-Dimension Analysis of Object Recognition Tasks
Authors: Michael Lindenbaum, Shai Ben-David
Venue: Journal of Mathematical Imaging and Vision (1999)

We analyze the amount of data needed to carry out various model-based recognition tasks in the context of a probabilistic data collection model. We focus on objects that may be described as semi-algebraic subsets of a Euclidean space. This is a very rich class that includes polynomially described bodies, as well as polygonal objects, as special cases. The class of object transformations considered is wide, and includes perspective and affine transformations of 2D objects, and perspective projections of 3D objects.We derive upper bounds on the number of data features (associated with non-zero spatial error) which provably suffice for drawing reliable conclusions. Our bounds are based on a quantitative analysis of the complexity of the hypotheses class that one has to choose from. Our central tool is the VC-dimension, which is a well-studied parameter measuring the combinatorial complexity of families of sets. It turns out that these bounds grow linearly with the task complexity, measured via the VC-dimension of the class of objects one deals with. We show that this VC-dimension is at most logarithmic in the algebraic complexity of the objects and in the cardinality of the model library.Our approach borrows from computational learning theory. Both learning and recognition use evidence to infer hypotheses but as far as we know, their similarity was not exploited previously. We draw close relations between recognition tasks and a certain learnability framework and then apply basic techniques of learnability theory to derive our sample size upper bounds. We believe that other relations between learning procedures and visual tasks exist and hope that this work will trigger further fruitful study along these lines.
Smooth Normal Approximations of epi-Lipschitzian subsets of $\mathbbR^n$
Authors: Bernard Cornet, Marc-Olivier Czarnecki
Venue: SIAM Journal on Control and Optimization (1999)

A sequence (Mk) of closed subsets of $\R^n$ converges normally to $M\subset \R^n$ if (sc) $M=\limsup M_{k}=\liminf M_k$ in the sense of Painlevé--Kuratowski and (nc) $\limsup {\rm G}(N_{M_k})\subset {\rm G}(N_{M})$, where G(NM) (resp., $ {\rm G}(N_{M_k})$) denotes the graph of NM (resp., $N_{M_k}$), Clarke's normal cone to (resp., $M_k$).This paper studies the normal convergence of subsets of $\R^n$ and mainly shows two results. The first result states that every closed epi-Lipschitzian subset M of $\R^n$, with a compact boundary, can be approximated by a sequence of smooth sets (Mk), which converges normally to M and such that the sets Mk and M are lipeomorphic for every k (i.e., the homeomorphism between M and Mk and its inverse are both Lipschitzian). The second result shows that, if a sequence (Mk) of closed subsets of $\R^n$ converges normally to an epi-Lipschitzian set M, and if we additionally assume that the boundary of Mk remains in a fixed compact set, then, for k large enough, the sets Mk and M are lipeomorphic.In Cornet and Czarnecki [ Cahier Eco-Maths 95-55, 1995], direct applications of these results are given to the study (existence, stability, etc.) of the generalized equation $0 \in f(x^*) +N_{M}(x^*)$ when M is a compact epi-Lipschitzian subset of $\R^n$ and $f: M \to\R^n$ is a continuous map (or more generally a correspondence).
Flexible Multiple Semicoarsening for Three-Dimensional Singularly Perturbed Problems
Authors: T. Washio, C. W. Oosterlee
Venue: SIAM Journal on Scientific Computing (1998)

We present robust parallel multigrid-based solvers for 3D scalar partial differential equations. The robustness is obtained by combining multiple semicoarsening strategies, matrix-dependent transfer operators, and a Krylov subspace acceleration. The basis for the 3D preconditioner is a 2D method with multiple semicoarsened grids based on the MG-S method from [C. W. Oosterlee, Appl. Numer. Math., 19(1995), pp. 115--128] and [T. Washio and C. W. Oosterlee, GMD Arbeitspapier 949, GMD, St. Augustin, Germany, 1995]. The 2D method is generalized to three dimensions with a line smoother in the third dimension. The method based on semicoarsening has been parallelized with the grid partitioning technique [J. Linden, B. Steckel, and K. Stüben, Parallel Comput., 7(1988), pp. 461--475], [O. A. McBryan et al., Impact Comput. Sci. Engrg., 3(1991), pp. 1--75] and is evaluated as a solver and as a preconditioner on a MIMD machine. The robustness of the 3D method is shown for finite volume and finite difference discretizations of 3D anisotropic diffusion equations and convection-dominated convection-diffusion problems.