ppxscal/embedding_network huggingface dataset:
Contextualizing the information space in federated digital libraries
Authors: M. P. Papazoglou, J. Hoppenbrouwers
Venue: ACM SIGMOD Record (1999)

Rapid growth in the volume of documents, their diversity, and terminological variations render federated digital libraries increasingly difficult to manage. Suitable abstraction mechanisms are required to construct meaningful and scalable document clusters, forming a cross-digital library information space for browsing and semantic searching. This paper addresses the above issues, proposes a distributed semantic framework that achieves a logical partitioning of the information space according to topic areas, and provides facilities to contextualize and landscape the available document sets in subject-specific categories.
Automatic node selection for high performance applications on networks
Authors: Jaspal Subhlok, Peter Lieu, Bruce Lowekamp
Venue: ACM SIGPLAN Notices (1999)

A central problem in executing performance critical parallel and distributed applications on shared networks is the selection of computation nodes and communication paths for execution. Automatic selection of nodes is complex as the best choice depends on the application structure as well as the expected availability of computation and communication resources. This paper presents a solution to this problem for realistic application and network scenarios. A new algorithm to jointly analyze computation and communication resources for different application demands is introduced and a framework for automatic node selection is developed on top of Remos, which is a query interface to network information. The paper reports results from a set of applications, including Airshed pollution modeling and magnetic resonance imaging, executing on a high speed network testbed. The results demonstrate that node selection is effective in enhancing application performance in the presence of computation load as well as network traffic. Under the network conditions used for experiments, the increase in execution time due to compute loads and network congestion was reduced by half with node selection. The node selection algorithms developed in this research are also applicable to dynamic migration of long running jobs.
On the content of materialized aggregate views
Authors: Stéphane Grumbach, Leonardo Tininini
Venue: Proceedings of the nineteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems (2000)

We consider the problem of answering queries using only materialized views. We first show that if the views subsume the query from the point of view of the information content, then the query can be answered using only the views, but the resulting query might be extremely inefficient. We then focus on aggregate views and queries over a single relation, which are fundamental in many applications such as data warehousing. We show that in this case, it is possible to guarantee that as soon as the views subsume the query, it can be completely rewritten in terms of the views in a simple query language. Our main contribution is the conception of various rewriting algorithms which run in polynomial time, and the proof of their completeness which relies on combinatorial arguments. Finally, we discuss the choice of materializing or not ratio views such as average and percentage, important for the design of materialized views. We show that it has an impact on the information content, which can be used to protect data, as well as on the maintenance of views.
Two- and Higher-Dimensional Pattern Matching in Optimal Expected Time
Authors: Juha Kärkkäinen, Esko Ukkonen
Venue: SIAM Journal on Computing (1999)

Algorithms with optimal expected running time are presented for searching the occurrences of a two-dimensional m X m pattern P in a two-dimensional n X n text T over an alphabet of size c. The algorithms are based on placing in the text a static grid of test points, determined only by n, m, and c (not dynamically by earlier test results). Using test strings read from the test points the algorithms eliminate as many potential occurrences of P as possible. The remaining potential occurrences are separately checked for actual occurrences. A suitable choice of the test point set leads to algorithms with expected running time O(n2logc m2/m2) using the uniform Bernoulli model of randomness. This is shown to be optimal by a generalization of a one-dimensional lower bound result by Yao. Experimental results show that the algorithms are efficient in practice, too. The method is also generalized for the k mismatches problem. The resulting algorithm has expected running time O(kn2logc m2/m2), provided that $k\leq(m\lfloor m/\lceil\log_c m^2\rceil\rfloor-1)/2$.\ All algorithms need preprocessing of P which takes time and space O(m2). The text processing can be done on-line, using a rather small window. The algorithms easily generalize to d-dimensional matching for any d.
An experimental study of a simple, distributed edge coloring algorithm
Authors: Madhav V. Marathe, Alessandro Panconesi, Larry D. Risinger
Venue: Proceedings of the twelfth annual ACM symposium on Parallel algorithms and architectures (2000)

We conduct an experimental analysis of a distributed, randomized algorithm for edge coloring simple undirected graphs. The algorithm is extremely simple, yet, according to the probabilistic analysis, it computes nearly optimal colorings very quickly [12]. We test the algorithm on a number of random as well as non-random graph families. The test cases were chosen based on two objectives &mdash; (i) to provide insights into the worst case behavior (in terms of time and quality) of the algorithm and (ii) to test the performance of the algorithm with instances that are likely to arise in practice. Our main results include the following: The empirical results obtained compare very well with the recent empirical results reported by other researchers [5, 6, 18]. The empirical confirm the bounds on the running time and the solution quality as claimed in the theoretical paper. Our results show that for certain classes of graphs the algorithm is likely to perform much better than the analysis suggests The results demonstrate that the algorithm might be well suited (from a theoretical as well as practical stand-point) for edge coloring graphs quickly and efficiently in a distributed setting. Based on our empirical study, we propose a simple modification of the original algorithm with substantially improved performance in practice.
A Comparison Design of Comb Decimators for Sigma-Delta Analog-to-Digital Converters
Authors: Yonghong Gao, Lihong Jia, Jouni Isoaho, Hannu Tenhunen
Venue: Analog Integrated Circuits and Signal Processing (2000)

This paper presents a comparison design of comb decimators based on the non-recursive algorithm and the recursive algorithm. Compared with the recursive algorithm, the main advantage of the non-recursive algorithm is its abilities of reducing power consumption and increasing circuit speed especially when the decimation ratio and filter order are high. Based on the non-recursive algorithm, a decimator with programmable filter orders (3rd, 4th and 5th), decimation ratios (8, 16, 32 and 64) and input bits (1 and 2 bits) has been implemented in a 0.6 &mu;m 3.3 V CMOS process. Its measured core power consumption is 44 mW at the oversampling rate of 25 MHz and its highest input data rate is 110 MHz.
Incremental formalization with the hyper-object substrate
Authors: Frank M. Shipman,  III, Raymond J. McCall
Venue: ACM Transactions on Information Systems (TOIS) (1999)

Computers require formally represented information to perform computations that support users; yet users who have needed such support have often proved to be unable or unwilling to formalize it. To address this problem, this article introduces an approach called incremental formalization, in which, first, users express information informally and then the system aids them in formalizing it. Incremental formalization requires a system architecture the (1) integrates formal and informal representations and (2) supports progressive formalization of information. The system should have both tools to capture naturally available informal information and techniques to suggest possible formalizations of this information. The hyper-object substrate (HOS) was developed to satisfy these requirements. HOS has been applied to a number of problem domains, including network design, archeological site analysis, and neuroscience education. Users have been successful in adding informal information and then later formalizing it incrementally with the aid of the system. Our experience with HOS has reaffirmed the need for information spaces to evolve during use and has identified additional considerations in the design and instantiation of systems enabling and supporting incremental formalization
Symmetric Versus Non-Symmetric Spin Models for Link Invariants
Authors: François Jaeger, Kazumasa Nomura
Venue: Journal of Algebraic Combinatorics: An International Journal (1999)

We study spin models as introduced in [20]. Such a spin model can be defined as a square matrix satisfying certain equations, and can be used to compute an associated link invariant. The link invariant associated with a symmetric spin model depends only trivially on link orientation. This property also holds for quasi-symmetric spin models, which are obtained from symmetric spin models by certain &ldquo;gauge transformations&rdquo; preserving the associated link invariant. Using a recent result of [16] which asserts that every spin model belongs to some Bose-Mesner algebra with duality, we show that the transposition of a spin model can be realized by a permutation of rows. We call the order of this permutation the index of the spin model. We show that spin models of odd index are quasi-symmetric. Next, we give a general form for spin models of index 2 which implies that they are associated with a certain class of symmetric spin models. The symmetric Hadamard spin models of [21] belong to this class and this leads to the introduction of non-symmetric Hadamard spin models. These spin models give the first known example where the associated link invariant depends non-trivially on link orientation. We show that a non-symmetric Hadamard spin model belongs to a certain triply regular Bose-Mesner algebra of dimension 5 with duality, and we use this to give an explicit formula for the associated link invariant involving the Jones polynomial.
Optimal Production Policies for Multi-Stage Systems with Setup Costs and Uncertain Capacities
Authors: Juhwen Hwang, Medini R. Singh
Venue: Management Science (1998)

The increased complexity of modern manufacturing has led to uncertainties in production processes. Factors such as unplanned machine maintenance, tool unavailability, and complex process adjustments make it difficult to maintain a predictable level of output. To be effective, an appropriate production model must incorporate these uncertainties into the representation of the production process. This paper considers a one-time production of an application-specific product which must follow a fixed routing through the manufacturing system. The flow of items can be modeled as a multi-stage serial production line. The productive capacity is uncertain at each stage and the decision to produce at any stage incurs a significant setup cost. Semifinished products have little value and inability to satisfy the demand incurs a penalty for each unit of unmet demand. We show that the optimal production policy for this system can be characterized by two critical numbers, which can be computed apriori based on the cost parameters and distributional information for all downstream stages. Sensitivity of the critical numbers is also explored.
Alternatives: exploring information appliances through conceptual design proposals
Authors: Bill Gaver, Heather Martin
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (2000)

As a way of mapping a design space for a project on information appliances, we produced a workbook describing about twenty conceptual design proposals. On the one hand, they serve as suggestions that digital devices might embody values apart from those traditionally associated with functionality and usefulness. On the other, they are examples of research through design, balancing concreteness with openness to spur the imagination, and using multiplicity to allow the emergence of a new design space. Here we describe them both in terms of content and process, discussing first the values they address and then how they were crafted to encourage a broad discussion with our partners that could inform future stages of design.
Java and distributed object models: an analysis
Authors: Marjan Hericko, Matjaz B. Juric, Ales Zivkovic, Ivan Rozman, Tomaz Domajnko, Marjan Krisper
Venue: ACM SIGPLAN Notices (1998)

Java has an important role in building distributed object oriented web enabled applications. In the article an analysis of two distributed object models in context of Java language is presented. Several aspects of RMI and CORBA such as features, maturity, support for legacy systems, learning curve and ease of development are compared. A special emphasis is given to the performances. Different testing scenarios give a complete overview about real world performances of both architectures. Based on the comparison results, recommendations for selecting the most appropriate architecture for a given problem domain are presented. Therefore the paper contributes to the understanding of the distributed object architectures and to the study of Java RMI and CORBA performances.
An efficient bitmap encoding scheme for selection queries
Authors: Chee-Yong Chan, Yannis E. Ioannidis
Venue: ACM SIGMOD Record (1999)

Bitmap indexes are useful in processing complex queries in decision support systems, and they have been implemented in several commercial database systems. A key design parameter for bitmap indexes is the encoding scheme, which determines the bits that are set to 1 in each bitmap in an index. While the relative performance of the two existing bitmap encoding schemes for simple selection queries of the form &ldquo;v1 &le; A &le; v2&rdquo; is known (specifically, one of the encoding schemes is better for processing equality queries; i.e., v1 = v2, while the other is better for processing range queries; i.e., v1 < v2), it remains an open question whether these two encoding schemes are indeed optimal for their respective query classes in the sense that there is no other encoding scheme with better space-time tradeoff. In this paper, we establish a number of optimality results for the existing encoding schemes; in particular, we prove that neither of the two known schemes is optimal for the class of two-sided range queries. We also propose a new encoding scheme and prove that it is optimal for that class. Finally, we present an experimental study comparing the performance of the new encoding scheme with that of the existing ones as well as four hybrid encoding schemes for both simple selection queries and the more general class of membership queries of the form &ldquo;A &isin; {v1, v2, .&hellip;, vk}&rdquo;. These results demonstrate that the new encoding scheme has an overall better space-time performance than existing schemes.
An Efficient Method To Estimate Bagging&lsquo;s Generalization Error
Authors: David H. Wolpert, William G. Macready
Venue: Machine Learning (1999)

Bagging (Breiman, 1994a) is a technique that tries to improve a learning algorithm&lsquo;s performance by using bootstrap replicates of the training set (Efron Tibshirani, 1993, Efron, 1979). The computational requirements for estimating the resultant generalization error on a test set by means of cross-validation are often prohibitive, for leave-one-out cross-validation one needs to train the underlying algorithm on the order of m&nu; times, where m is the size of the training set and &nu; is the number of replicates. This paper presents several techniques for estimating the generalization error of a bagged learning algorithm without invoking yet more training of the underlying learning algorithm (beyond that of the bagging itself), as is required by cross-validation-based estimation. These techniques all exploit the bias-variance decomposition (Geman, Bienenstock Doursat, 1992, Wolpert, 1996). The best of our estimators also exploits stacking (Wolpert, 1992). In a set of experiments reported here, it was found to be more accurate than both the alternative cross-validation-based estimator of the bagged algorithm&lsquo;s error and the cross-validation-based estimator of the underlying algorithm&lsquo;s error. This improvement was particularly pronounced for small test sets. This suggests a novel justification for using bagging&mdash;more accurate estimation of the generalization error than is possible without bagging.
Existence and Approximation of Robust Solutions of Variational Inequality Problems over Polytopes
Authors: Gerard vander Laan, Dolf Talman, Zaifu Yang
Venue: SIAM Journal on Control and Optimization (1999)

We study nonlinear variational inequality problems over polytopes from a viewpoint of stability and propose a new solution concept. Extending an earlier concept proposed by Yang [Z. Yang, SIAM J. Control Optim., 34 (1996), pp. 491--506] on the unit simplex, we will introduce the concept of the robust stationary point, which is a refinement of the concept of the stationary point. Though a stationary point need not be robust, it is shown that every continuous function on a polytope has a robust stationary point. We develop a simplicial algorithm to compute a robust stationary point of a continuous function on a polytope. The algorithm can be briefly stated as follows. Starting with any point in the relative interior of a polytope, the algorithm generates a piecewise linear path which leads to an approximate robust stationary point of any a priori chosen accuracy within a finite number of steps. Moreover, we also discuss several numerical examples and apply the new concept to noncooperative games and economic equilibrium problems.
An Introduction to Simulated Annealing Algorithms for the Computation ofEconomic Equilibrium
Authors: Lihua Wu, Yuyun Wang
Venue: Computational Economics (1998)

Economic equilibrium computation has raised the issue of global optimization algorithms since economic equilibrium problems can be cast as a global optimization problem. However, nearly all conventional algorithms stop when they find a local optimum. Over the last decade a number of new optimization algorithms have appeared, simulated annealing is one of them. It is a powerful stochastic search algorithm applicable to a wide range of problems for which little prior knowledge is available, and it asymptotically probabilistically converges to a global optimum. In this paper, we will give a brief introduction to simulated annealing and apply it to the computation of economic equilibrium. We also reported our computational experience in the paper. This early result shows that the application of simulated annealing to computation of economic equilibrium is encouraging and it deserves further research.
RoboProf and an introductory computer programming course
Authors: Charlie Daly
Venue: ACM SIGCSE Bulletin (1999)

RoboProf is an online teaching system. It is based on WWW technology and can easily incorporate WWW-compatible media such as graphics, audio and video. It is structured as a self-paced course book: RoboProf presents the student with information on a closely-defined topic and then marks a set of exercises covering that material. When the students results are satisfactory, a new topic is introduced.The idea behind RoboProf is to increase motivation by borrowing ideas from certain games. These ideas include providing a challenge, giving quick feedback, making progress visible and encouraging experimentation.RoboProf was used to teach an introductory computer programming course. An introductory computer programming course must cover two main areas, the computer model (syntax and semantics of a programming language) and program design. In this paper I show how RoboProf can be effectively used to help teach the syntax and semantics of a programming language.
Charting past, present, and future research in ubiquitous computing
Authors: Gregory D. Abowd, Elizabeth D. Mynatt
Venue: ACM Transactions on Computer-Human Interaction (TOCHI) (2000)

The proliferation of computing into the physical world promises more than the ubiquitous availability of computing infrastructure; it suggest new paradigms of interaction inspired by constant access to information and computational capabilities. For the past decade, application-driven research on abiquitous computing (ubicomp) has pushed three interaction themes:natural interfaces, context-aware applications,andautomated capture and access. To chart a course for future research in ubiquitous computing, we review the accomplishments of these efforts and point to remaining research challenges. Research in ubiquitious computing implicitly requires addressing some notion of scale, whether in the number and type of devices, the physical space of distributed computing, or the number of people using a system. We posit a new area of applications research, everyday computing, focussed on scaling interaction with respect to time. Just as pushing the availiability of computing away from the traditional desktop fundamentally changes the relationship between humans and computers, providing continuous interaction moves computing from a localized tool to a constant companion. Designing for continous interaction requires addressing interruption and reumption of intreaction, representing passages of time and providing associative storage models. Inherent in all of these interaction themes are difficult issues in the social implications of ubiquitous computing and the challenges of evaluating> ubiquitious computing research. Although cumulative experience points to lessons in privacy, security, visibility, and control, there are no simple guidelines for steering research efforts. Akin to any efforts involving new technologies, evaluation strategies form a spectrum from technology feasibility efforts to long-term use studies&mdash;but a user-centric perspective is always possible and necessary
Memory access scheduling
Authors: Scott Rixner, William J. Dally, Ujval J. Kapasi, Peter Mattson, John D. Owens
Venue: Proceedings of the 27th annual international symposium on Computer architecture (2000)

The bandwidth and latency of a memory system are strongly dependent on the manner in which accesses interact with the &ldquo;3-D&rdquo; structure of banks, rows, and columns characteristic of contemporary DRAM chips. There is nearly an order of magnitude difference in bandwidth between successive references to different columns within a row and different rows within a bank. This paper introduces memory access scheduling, a technique that improves the performance of a memory system by reordering memory references to exploit locality within the 3-D memory structure. Conservative reordering, in which the first ready reference in a sequence is performed, improves bandwidth by 40% for traces from five media benchmarks. Aggressive reordering, in which operations are scheduled to optimize memory bandwidth, improves bandwidth by 93% for the same set of applications. Memory access scheduling is particularly important for media processors where it enables the processor to make the most efficient use of scarce memory bandwidth.