ppxscal/embedding_network huggingface dataset:
Lower Bounds on Communication Loads and Optimal Placements in Torus Networks
Authors: M. Cemil Azizoglu, Ömer Egecioglu
Venue: IEEE Transactions on Computers (2000)

Fully populated torus-connected networks, where every node has a processor attached, do not scale well since load on edges increases superlinearly with network size under heavy communication, resulting in a degradation in network throughput. In a partially populated network, processors occupy a subset of available nodes and a routing algorithm is specified among the processors placed. Analogous to multistage networks, it is desirable to have the total number of messages being routed through a particular edge in toroidal networks increase at most linearly with the size of the placement. To this end, we consider placements of processors which are described by a given placement algorithm parameterized by $k$ and $d$: We show formally, that to achieve linear communication load in a $d$-dimensional $k$-torus, the number of processors in the placement must be equal to $c k^{d-1}$ for some constant $c$. Our approach also gives a tighter lower bound than existing bounds for the maximum load of a placement for arbitrary number of dimensions for placements with sufficient symmetries. Based on these results, we give optimal placements and corresponding routing algorithms achieving linear communication load in tori with arbitrary number of dimensions.
Boundary Observability, Controllability, and Stabilization of Linear Elastodynamic Systems
Authors: Fatiha Alabau, Vilmos Komornik
Venue: SIAM Journal on Control and Optimization (1999)

In 1988 Lions obtained observability and exact controllability results for linear homogeneous isotropic elastodynamic systems [ SIAM Rev., 30 (1988), pp. 1--68]. Applying some new identities we extend his theorems to nonisotropic systems. In 1991 Lagnese obtained uniform stabilizability results for two-dimensional linear homogeneous isotropic systems by applying a somewhat artificial feedback [Nonlinear Anal., 16 (1991), pp. 35--54]. Then he asked whether analogous results hold for a natural and physically implementable boundary feedback. Using some new identities and applying a method introduced in 1987 by Zuazua and the second author [ J. Math. Pures. Appl., 69 (1990), pp. 33--54], we give an affirmative answer to this question in all dimensions and also for nonisotropic systems. Moreover, we obtain good decay estimates. Finally, applying a recent general method of uniform stabilization, we construct boundary feedbacks leading to arbitrarily large energy decay rates.
Comprehensive statistical method for protein fold recognition
Authors: Jadwiga R. Bieńkowska, Lihua Yu, Sophia Zarakhovich, Robert G. Rogers,  Jr., Temple F. Smith
Venue: Proceedings of the fourth annual international conference on Computational molecular biology (2000)

We present a protein fold recognition method that uses a comprehensive statistical interpretation of structural Hidden Markov Models (HMMs). The structure/fold recognition is done by summing the probabilities of all sequence-to-structure alignments Conventionally, Boltzmann statistics dictate that the optimal alignment can give an estimate of the lowest free energy of the sequence conformation imposed by the structural model. The alignment is optimized for a scoring function that is interpreted as a free energy of an amino acid in a structural environment. Near-optimal alignments are ignored, regardless of how likely they might be compared to the optimal alignment. Here we investigate an alternative view. A structure model can be seen as a statistical representation of an ensemble of similar structures. The optimal alignment is always the most probable, but sub-optimal alignments may have comparable probabilities. These sub-optimal alignments can be interpreted as optimal alignments to the &ldquo;other&rdquo; structures from the ensemble or optimal alignments under minor fluctuations in the scoring function. Summing probabilities for all alignments gives an estimate of sequence-model compatibility. We have built a set of structural HMMs for 188 protein structures, and have compared two methods for identifying the structure compatible with a sequence: by the optimal alignment probability and by the total probability. Fold recognition by total probability was 40% more accurate than fold recognition by the optimal alignment probability.
Testability Enhancement for Control-Flow Intensive Behaviors
Authors: Kelly A. Ockunzzi, Christos A. Papachristou
Venue: Journal of Electronic Testing: Theory and Applications (1998)

A BIST-based test synthesis methodology for control-flow intensive behaviors is proposed. This methodology targets the control statements in a behavioral description, such as if-then-else and loop statements, because such statements can introduce testability problems in the resulting circuit. How well the operations in each branch of a control statement can be tested depends on the probability of taking each branch and the quality of the test patterns used in each branch. Behavioral modifications are presented that can resolve these testability issues. The proposed methodology systematically identifies poor testability areas within a behavior and applies the behavioral modifications to improve the testability. Experimental results from six practical examples show that this technique is effective.
Static scheduling algorithms for allocating directed task graphs to multiprocessors
Authors: Yu-Kwong Kwok, Ishfaq Ahmad
Venue: ACM Computing Surveys (CSUR) (1999)

Static scheduling of a program represented by a directed task graph on a multiprocessor system to minimize the program completion time is a well-known problem in parallel processing. Since finding an optimal schedule is an NP-complete problem in general, researchers have resorted to devising efficient heuristics. A plethora of heuristics have been proposed based on a wide spectrum of techniques, including branch-and-bound, integer-programming, searching, graph-theory, randomization, genetic algorithms, and evolutionary methods. The objective of this survey is to describe various scheduling algorithms and their functionalities in a contrasting fashion as well as examine their relative merits in terms of performance and time-complexity. Since these algorithms are based on diverse assumptions, they differ in their functionalities, and hence are difficult to describe in a unified context. We propose a taxonomy that classifies these algorithms into different categories. We consider 27 scheduling algorithms, with each algorithm explained through an easy-to-understand description followed by an illustrative example to demonstrate its operation. We also outline some of the novel and promising optimization approaches and current research trends in the area. Finally, we give an overview of the software tools that provide scheduling/mapping functionalities.
A Variable Memory Quasi-Newton Training Algorithm
Authors: Seán Mcloone, George Irwin
Venue: Neural Processing Letters (1999)

A new neural network training algorithm which optimises performance in relation to the available memory is described. Numerically it has equivalent properties to Full Memory BFGS optimisation (FM) when there are no restrictions on memory and to FM with periodic reset when memory is limited. Achievable performance is determined by the ratio between available memory and problem size and accordingly varies between that of the full and memory-less versions of the BFGS algorithm.
Team projects in distance education: a case in HCI design
Authors: Herman Koppleman, Charles P. A. G van der Mast, Elisabeth M. A. G van Dijk, Gerrit C. van der Veer
Venue: ACM SIGCSE Bulletin (2000)

Until recently it was difficult to incorporate team projects in distance education. Nowadays, however, new technology is available which allows for distance teamwork. In this paper we will describe a project-oriented course on human-computer interaction. The course is meant for computer science students in distance education. A serious restriction is caused by the fact that the students study at home, where they usually only have a slow connection to Internet at their disposal. We will focus on the way we structured the course to make distance teamwork possible. Furthermore the tools we offered the students will be discussed. Finally, in the paper we will present the first experiences gained in a pilot project with 12 computer science students.
Closest pair queries in spatial databases
Authors: Antonio Corral, Yannis Manolopoulos, Yannis Theodoridis, Michael Vassilakopoulos
Venue: ACM SIGMOD Record (2000)

This paper addresses the problem of finding the K closest pairs between two spatial data sets, where each set is stored in a structure belonging in the R-tree family. Five different algorithms (four recursive and one iterative) are presented for solving this problem. The case of 1 closest pair is treated as a special case. An extensive study, based on experiments performed with synthetic as well as with real point data sets, is presented. A wide range of values for the basic parameters affecting the performance of the algorithms, especially the effect of overlap between the two data sets, is explored. Moreover, an algorithmic as well as an experimental comparison with existing incremental algorithms addressing the same problem is presented. In most settings, the new algorithms proposed clearly outperform the existing ones.
XTRACT: a system for extracting document type descriptors from XML documents
Authors: Minos Garofalakis, Aristides Gionis, Rajeev Rastogi, S. Seshadri, Kyuseok Shim
Venue: ACM SIGMOD Record (2000)

XML is rapidly emerging as the new standard for data representation and exchange on the Web. An XML document can be accompanied by a Document Type Descriptor (DTD) which plays the role of a schema for an XML data collection. DTDs contain valuable information on the structure of documents and thus have a crucial role in the efficient storage of XML data, as well as the effective formulation and optimization of XML queries. In this paper, we propose XTRACT, a novel system for inferring a DTD schema for a database of XML documents. Since the DTD syntax incorporates the full expressive power of regular expressions, naive approaches typically fail to produce concise and intuitive DTDs. Instead, the XTRACT inference algorithms employ a sequence of sophisticated steps that involve: (1) finding patterns in the input sequences and replacing them with regular expressions to generate &ldquo;general&rdquo; candidate DTDs, (2) factoring candidate DTDs using adaptations of algorithms from the logic optimization literature, and (3) applying the Minimum Description Length (MDL) principle to find the best DTD among the candidates. The results of our experiments with real-life and synthetic DTDs demonstrate the effectiveness of XTRACT's approach in inferring concise and semantically meaningful DTD schemas for XML databases.
Evaluation of Capacity and Spectral Efficiency of the Emerging Digital Mobile Systems
Authors: Ibrahim A. al-Kadi
Venue: International Journal of Network Management (1996)

Digital cellular systems will have profound implications for the integration of mobile computing and communications allowing true networking on the move. The European-developed GSM system is rapidly becoming the de-facto world standard for mobile communications. Other emerging standards include IS-54 in North America and PDC in Japan, in addition to the CDMA standard &lpar;IS-95&rpar; in the USA. The aim of this article is to compare the four emerging standards, with particular emphasis on their user capacity and spectrum utilization efficiency.
Memory binding for performance optimization of control-flow intensive behaviors
Authors: Kamal S. Khouri, Ganesh Lakshminarayana, Niraj K. Jha
Venue: Proceedings of the 1999 IEEE/ACM international conference on Computer-aided design (1999)

This paper presents a memory binding algorithm for behaviors that are characterized by the presence of conditionals and deeply-nested loops that access memory extensively through arrays. Unlike previous works, this algorithm examines the effects of branch probabilities and allocation constraints. First, we demonstrate, through examples, the importance of incorporating branch probabilities and allocation constraint information when searching for a performance-efficient memory binding. We also show the interdependence of these two factors and how varying one without considering the other may greatly affect the performance of the behavior. Second, we introduce a memory binding algorithm that has the ability to examine numerous bindings by employing an efficient performance estimation procedure. The estimation procedure exploits locality of execution, which is an inherent characteristic of target behaviors. This enables the performance estimation technique to look at the global impact of the different bindings, given the allocation constraints.We tested our algorithm using a number of benchmarks from the parallel computing domain. A series of experiments demonstrates the algorithm's ability to produce bindings that optimize performance, meet memory allocation constraints, and adapt to different resource constraints and branch probabilities. Results show that the algorithm requires 37% fewer memories with a performance loss of only 0.3% when compared to a parallel memory architecture. When compared to the best of a series of random memory bindings, the algorithm improves schedule performance by 21%.
Space-efficient Routing Tables for Almost All Networks and the Incompressibility Method
Authors: Harry Buhrman, Jaap-Henk Hoepman, Paul Vitányi
Venue: SIAM Journal on Computing (1999)

We use the incompressibility method based on Kolmogorov complexity to determine the total number of bits of routing information for almost all network topologies. In most models for routing, for almost all labeled graphs, $\Theta (n^2)$ bits are necessary and sufficient for shortest path routing. By "almost all graphs" we mean the Kolmogorov random graphs which constitute a fraction of 1 - 1/nc of all graphs on n nodes, where c > 0 is an arbitrary fixed constant. There is a model for which the average case lower bound rises to $\Omega(n^2 \log n )$ and another model where the average case upper bound drops to $O(n \log^2 n)$. This clearly exposes the sensitivity of such bounds to the model under consideration. If paths have to be short, but need not be shortest (if the stretch factor may be larger than 1), then much less space is needed on average, even in the more demanding models. Full-information routing requires $\Theta (n^3)$ bits on average. For worst-case static networks we prove an $\Omega(n^2 \log n )$ lower bound for shortest path routing and all stretch factors
A domain specific software architecture style for CSCD system
Authors: Baojian Li, Guangzhou Zeng, Zongkai Lin
Venue: ACM SIGSOFT Software Engineering Notes (1999)

This paper proposes a domain-specific software architecture style. In the architecture style we define three software component types: procedure components, object components and agent components. We design a software bus or connector called Tribus to facilitate interactions among these components and specify one way quotation relations between different component types and two-way quotation relations between components of the same type. We also give an application example of the software architecture style in the domain of Computer Supported Collaborative Design (CSCD).
Co-design of interleaved memory systems
Authors: Hua Lin, Wayne Wolf
Venue: Proceedings of the eighth international workshop on Hardware/software codesign (2000)

Memory interleaving is a cost-efficient approach to increase bandwidth. Improving data access locality and reducing memory access conflicts are two important aspects to achieve high efficiency for interleaved memory. In this paper, we introduce a design framework that integrates these two optimizations, in order to find out minimal memory banks and channels required in the embedded system under performance restriction. Several important techniques, loop and data layout transformations for data access locality, extracting data streams, conflict cache miss reduction as well as data placement and optimally reordered access for interleaved memories, are incorporated in the design framework. Experiments show that our co-design method results in substantially less hardware requirement compared to the implementations without optimization.
A study on data point search for HG-trees
Authors: Joseph Kuan, Paul Lewis
Venue: ACM SIGMOD Record (1999)

A point data retrieval algorithm for the HG-tree is introduced which improves the number of nodes accessed. The HG-tree is a multidimensional indexing tree designed for point data and it is a simple modification from the Hilbert R-tree for indexing spatial data. The HG-tree data search method mainly makes use of the Hilbert index values to search for exact data, instead of using conventional point search methods as used in most of the R-tree papers. The use of Hilbert curve values and MBR can reduce the spatial cover of an MBR. Several R-tree variants have been developed; R*-tree, S-tree, Hilbert R-tree, and R*-tree combined with the linear split method by Ang et al. Our search method on the HG-tree gives a superior speed performance compared to all other R-tree variants.
Out-of-core simplification of large polygonal models
Authors: Peter Lindstrom
Venue: Proceedings of the 27th annual conference on Computer graphics and interactive techniques (2000)

We present an algorithm for out-of-core simplification of large polygonal datasets that are too complex to fit in main memory. The algorithm extends the vertex clustering scheme of Rossignac and Borrel [13] by using error quadric information for the placement of each cluster's representative vertex, which better preserves fine details and results in a low mean geometric error. The use of quadrics instead of the vertex grading approach in [13] has the additional benefits of requiring less disk space and only a single pass over the model rather than two. The resulting linear time algorithm allows simplification of datasets of arbitrary complexity. In order to handle degenerate quadrics associated with (near) flat regions and regions with zero Gaussian curvature, we present a robust method for solving the corresponding underconstrained least-squares problem. The algorithm is able to detect these degeneracies and handle them gracefully. Key features of the simplification method include a bounded Hausdorff error, low mean geometric error, high simplification speed (up to 100,000 triangles/second reduction), output (but not input) sensitive memory requirements, no disk space overhead, and a running time that is independent of the order in which vertices and triangles occur in the mesh.
A Structured Reduced Sequential Quadratic Programming andIts Application to a Shape Design Problem
Authors: Terry L. Herdman, Kyehong Kang
Venue: Computational Optimization and Applications (1998)

The objective of this work is to solve a model one dimensional duct design problem using a particular optimization method. The design problem is formulated as an equality constrained optimization, called {\it all at once} method, so that the analysis problem is not solved until the optimal design is reached. Furthermore, the sparsity structure in the Jacobian of the linearized constraints is exploited by decomposing the variables into the design and flow parts. To achieve this, sequential quadratic programming with BFGS update for the reduced Hessian of the Lagrangian function is used with the {\it variable reduction method} which preserves the structure of the Jacobian in representing the null space basis matrix. By updating the reduced Hessians of which the dimension is the number of design variables, the storage requirement for the Hessians is reduced by a large amount. In addition, the flow part of the Jacobian can be computed analytically.The algorithm with a line search globalization is described. A global and local analysis is provided with a modification of the paper by Byrd and Nocedal [Mathematical Programming 49(1991) pp 285-323] in which they analyzed a similar algorithm with the {\it orthogonal factorization method} which assumes the orthogonality of the null space basis matrix. Numerical results are obtained and compared favorably with results from the {\it black box method}, unconstrained optimization formulation.
Collinearity and Parallelism are Statistically Significant Second-Order Relations of Complex Cell Responses
Authors: Norbert Krüger
Venue: Neural Processing Letters (1998)

By investigating the second-order statistics of Gabor wavelet responses derived from natural images, we show that collinearity and parallelism are conspicuous relations. We give a precise mathematical characterization of these Gestalt principles by the conditional probability of two responses. Essential for our investigations is a non-linear transformation, initially utilized within the object recognition system [5], which transforms continuous Gabor wavelet responses into a binary code indicating the presence or absence of local oriented line segments.
Borders: An Efficient Algorithm for Association Generation in Dynamic Databases
Authors: Yonatan Aumann, Ronen Feldman, Orly Lipshtat, Heikki Manilla
Venue: Journal of Intelligent Information Systems (1999)

We consider the problem of finding association rules in a database with binary attributes. Most algorithms for finding such rules assume that all the data is available at the start of the data mining session. In practice, the data in the database may change over time, with records being added and deleted. At any given time, the rules for the current set of data are of interest. The naive, and highly inefficient, solution would be to rerun the association generation algorithm from scratch following the arrival of each new batch of data. This paper describes the Borders algorithm, which provides an efficient method for generating associations incrementally, from dynamically changing databases. Experimental results show an improved performance of the new algorithm when compared with previous solutions to the problem.
The composite health care system of tripler army medical center
Authors: Annie L. Speights
Venue: ACM SIGBIO Newsletter (1999)

This paper will briefly discuss the Composite Health Care System (CHCS) at Tripler Army Medical Center. It will define the system configuration of CHCS and show how CHCS provides a clinical application information system to support health care delivery to armed service personnel, retirees and beneficiaries, ensure medical readiness of military forces and support quality managed care. The paper will give an analysis of the challenge Tripler faced with the increasing number of calls for prescription refills and explain how the CHCS Executive Committee established a set of contingency policies to support and provide guidance during periods of planned and unplanned downtime. It will also discuss how CHCS was leveraged for the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) Information Management Initiative. Finally, it describes the automated security features designed to provide access control to the overall system of CHCS.
Error Estimates for the Solution of Linear Systems
Authors: C. Brezinski
Venue: SIAM Journal on Scientific Computing (1999)

Let Ax=b be a system of linear equations where A is a square and nonsingular matrix. When solving it by a direct or an iterative method, an approximate solution x* is obtained (x* denotes the current iterate in the case of an iterative method). In this paper, we propose estimates for the norm of the error e=x-x*. These estimates are valid for any nonsingular matrix and for approximations x* of x obtained by any method and, thus, they also implicitly take into account the effect of rounding errors.