ppxscal/embedding_network huggingface dataset:
Diffusive Relaxation Schemes for Multiscale Discrete-Velocity Kinetic Equations
Authors: Shi Jin, Lorenzo Pareschi, Giuseppe Toscani
Venue: SIAM Journal on Numerical Analysis (1998)

Many kinetic models of the Boltzmann equation have a diffusive scaling that leads to the Navier--Stokes-type parabolic equations, such as the heat equation, the porous media equations, the advection-diffusion equation, and the viscous Burgers equation. In such problems the diffusive relaxation parameter may differ in several orders of magnitude from the rarefied regimes to the hydrodynamic (diffusive) regimes, and it is desirable to develop a class of numerical schemes that can work uniformly with respect to this relaxation parameter. Earlier approaches that work from the rarefied regimes to the Euler regimes do not directly apply to these problems since here, in addition to the stiff relaxation term, the convection term is also stiff. Our idea is to reformulate the problem in the form commonly used for the relaxation schemes to conservation laws by properly combining the stiff component of the convection terms into the relaxation term. This, however, introduces new difficulties due to the dependence of the stiff source term on the gradient. We show how to overcome this new difficulty with an adequately designed, economical discretization procedure for the relaxation term. These schemes are shown to have the correct diffusion limit. Several numerical results in one and two dimensions are presented, which show the robustness, as well as the uniform accuracy, of our schemes.
Using the Concept of Intelligent Agents in FaultManagement of Distributed Services
Authors: Maria-Athina Mountzia, Gabi Dreo Rodosek
Venue: Journal of Network and Systems Management (1999)

This paper proposes the application of concepts from the area of intelligent agents to overcome deficiencies of existing management architectures regarding distribution of functionality and flexibility. Its main contribution is the proposal of a methodology for a flexible, distributed realization of complex management tasks. The main application areas are distributed services which are complex pieces of software, distributed across various heterogeneous end systems in a network. Mostly, they rely on the provision of other services as well. The approach relies on well-known concepts, such as cooperative distributed problem solving and intelligent agents, and offers a framework to combine these two concepts, providing a step on the roadmap to a flexible, distributed management architecture. The assessment of the approach is displayed throughout the paper by scenarios from the area of nontime critical fault management.
A Full Bayesian Approach to Curve and Surface Reconstruction
Authors: Daniel Keren, Michael Werman
Venue: Journal of Mathematical Imaging and Vision (1999)

When interpolating incomplete data, one can choose a parametric model, or opt for a more general approach and use a non-parametric model which allows a very large class of interpolants. A popular non-parametric model for interpolating various types of data is based on regularization, which looks for an interpolant that is both close to the data and also &ldquo;smooth&rdquo; in some sense. Formally, this interpolant is obtained by minimizing an error functional which is the weighted sum of a &ldquo;fidelity term&rdquo; and a &ldquo;smoothness term&rdquo;.The classical approach to regularization is: select &ldquo;optimal&rdquo; weights (also called hyperparameters) that should be assigned to these two terms, and minimize the resulting error functional.However, using only the &ldquo;optimal weights&rdquo; does not guarantee that the chosen function will be optimal in some sense, such as the maximum likelihood criterion, or the minimal square error criterion. For that, we have to consider all possible weights.The approach suggested here is to use the full probability distribution on the space of admissible functions, as opposed to the probability induced by using a single combination of weights. The reason is as follows: the weight actually determines the probability space in which we are working. For a given weight &lambda;, the probability of a function f is proportional to exp(&minus; &lambda; \int f^2_uu du) (for the case of a function with one variable). For each different &lambda;, there is a different solution to the restoration problem&semi; denote it by f_&lambda;. Now, if we had known &lambda;, it would not be necessary to use all the weights&semi; however, all we are given are some noisy measurements of f, and we do not know the correct &lambda;. Therefore, the mathematically correct solution is to calculate, for every &lambda;, the probability that f was sampled from a space whose probability is determined by &lambda;, and average the different f_&lambda;&lsquo;s weighted by these probabilities. The same argument holds for the noise variance, which is also unknown.Three basic problems are addressed is this work:&bull; Computing the MAP estimate, that is, the function f maximizing Pr(f/D) when the data D is given. This problem is reduced to a one-dimensional optimization problem.&bull; Computing the MSE estimate. This function is defined at each point x as \intf(x)Pr(f/D) {\cal D}f. This problem is reduced to computing a one-dimensional integral.In the general setting, the MAP estimate is not equal to the MSE estimate.&bull; Computing the pointwise uncertainty associated with the MSE solution. This problem is reduced to computing three one-dimensional integrals.
On changing from written to on-line tests in Computer Science I: an assessment
Authors: Amruth N. Kumar
Venue: ACM SIGCSE Bulletin (1999)

How do on-line tests compare with written tests in Computer Science I? Do students who do well in written tests also do well in an online test? Is an online test better or worse than a written test at assessing the problem-solving skills of a student? This paper summarizes the answers to these questions that we found during our switch from written to on-line testing.
An exploration into supporting artwork orientation in the user interface
Authors: George W. Fitzmaurice, Ravin Balakrishnan, Gordon Kurtenbach, Bill Buxton
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

Rotating a piece of paper while drawing is an integral and almost subconscious part of drawing with pencil and paper. In a similar manner, the advent of lightweight pen-based computers allow digital artwork to be rotated while drawing by rotating the entire computer. Given this type of manipulation we explore the implications for the user interface to support artwork orientation. First we describe an exploratory study to further motivate our work and characterize how artwork is manipulated while drawing. After presenting some possible UI approaches to support artwork orientation, we define a new solution called a rotating user interface (RUIs). We then discuss design issues and requirements for RUIs based on our exploratory study.
Storing semistructured data with STORED
Authors: Alin Deutsch, Mary Fernandez, Dan Suciu
Venue: Proceedings of the 1999 ACM SIGMOD international conference on Management of data (1999)

Systems for managing and querying semistructured-data sources often store data in proprietary object repositories or in a tagged-text format. We describe a technique that can use relational database management systems to store and manage semistructured data. Our technique relies on a mapping between the semistructured data model and the relational data model, expressed in a query language called STORED. When a semistructured data instance is given, a STORED mapping can be generated automatically using data-mining techniques. We are interested in applying STORED to XML data, which is an instance of semistructured data. We show how a document-type-descriptor (DTD), when present, can be exploited to further improve performance.
Parallel and distributed execution of constraint programs
Authors: Enrico Pontelli
Venue: ACM SIGSOFT Software Engineering Notes (2000)

The goal of this research project is to study techniques and methodologies for execution of Constraint logic programs on parallel and distributed architectures. These models will be applied to implicit and explicit parallelization of complex and irregular symbolic applications, such as those arising in Natural Language Processing, Knowledge-based Systems, and Digital Libraries, and to provide novel frameworks for advanced World-Wide Web programming and coordination of software components.
A secure dynamic copy protocol in real-time secure database systems
Authors: Sungyoung Lee, Byeong-Soo Jeong, Hyon-Woo Seung
Venue: Proceedings of the ACM SIGPLAN 1999 workshop on Languages, compilers, and tools for embedded systems (1999)

Concurrency control for real-time secure database systems must satisfy not only logical data consistency but also timing constraints and security requirements associated with transactions. These conflicting natures between timing constraints and security requirements are often resolved by maintaining several versions (or secondary copies) on the same data items. In this paper, we propose a new lock-based concurrency control protocol, Secure Dynamic Copy Protocol, ensuring both conflicting requirements. Our protocol aims for reducing the storage overhead of maintaining secondary copies and minimizing the processing overhead of update history. The main idea of our protocol is to keep a secondary copy only when it is needed to resolve the conflicting read/write operations in real time secure database systems. For doing this, a secondary copy is dynamically created and removed during a transaction's read/write operations. While comparing the existing real-time security protocol, we have also examined the performance characteristics of our protocol through simulation under different workloads. The results show that our protocol consumed less storage and decreased the deadline missing transactions.
Bipartite Edge Coloring in $O(\Delta m)$ Time
Authors: Alexander Schrijver
Venue: SIAM Journal on Computing (1999)

We show that a minimum edge coloring of a bipartite graph can be found in $O(\Delta m)$ time, where $\Delta$ and m denote the maximum degree and the number of edges of G, respectively. It is equivalent to finding a perfect matching in a k-regular bipartite graph in O(km) time.By sharpening the methods, a minimum edge coloring of a bipartite graph can be found in $O((p_{\max}(\Delta)+\log \Delta)m)$ time, where $p_{\max}(\Delta)$ is the largest prime factor of $\Delta$. Moreover, a perfect matching in a k-regular bipartite graph can be found in O(pmax(k)m)time.
Implementing the spirit of SQL-99
Authors: Paul Brown
Venue: Proceedings of the 1999 ACM SIGMOD international conference on Management of data (1999)

This paper describes the current INFORMIX IDS/UD release (9.2 or Centaur) and compares and contrasts its functionality with the features of the SQL-99 language standard. INFORMIX and Illustra have been shipping DBMSs implementing the spirit of the SQL-99 standard for five years. In this paper, we review our experience working with ORDBMS technology, and argue that while SQL-99 is a huge improvement over SQL-92, substantial further work is necessary to make object-relational DBMSs truly useful. Specifically, we describe several interesting pieces of functionality unique to IDS/UD, and several dilemmas our customers have encountered that the standard does not address.
Optimization Based Algorithms for Finding Minimal Cost Ring Covers in Survivable Networks
Authors: J. L. Kennington, V. S. S. Nair, M. H. Rahman
Venue: Computational Optimization and Applications (1999)

Designing low cost SONET networks composed of self-healing rings is an important problem facing the providers of broadband services. This manuscript demonstrates how optimization technology coupled with the highly efficient CPLEX software system can be used to help solve this important problem. For the first time, provable optimal designs are presented for several small networks which appear in the literature. In an empirical analysis, we demonstrate how this same methodology can be used to find good (but not provably optimal) designs for large test cases.
Table-based QoS control for embedded real-time systems
Authors: Sugawara Tomoyoshi, Tatsukawa Kosuke
Venue: Proceedings of the ACM SIGPLAN 1999 workshop on Languages, compilers, and tools for embedded systems (1999)

This paper proposes a new QoS control scheme that is suited for embedded real-time systems. Our scheme focused on real-time systems where both device control and multimedia processing are required. Such systems needs to keep timing constraints of control tasks while providing the highest possible quality of service(QoS) to multimedia processing tasks. Although many QoS control schemes are proposed and used in distributed multimedia systems, they are not suited for such real-time systems. Their QoS control policies cannot exactly keep the timing constraints of control tasks.To overcome this problem we chose a scheme which uses a table describing resource requirements of all tasks. Resource allocations for tasks and total resource utilization in a system can be calculated from the table. Using our scheme, any QoS control policies, such as a fair-share policy or a priority based policy, can be implemented. In other words, it has become possible for the first time to allow the intention of system designers to be directly reflected on QoS control.We have implemented a CPU time QoS control mechanism based on our proposed scheme and evaluated it on a mu;-ITRON Ver. 3.0 based real-time OS. The evaluation results demonstrate that the QoS control scheme can keep deadline misses low and CPU utilization high under an overloaded state. The results also show that overhead of the QoS control mechanism is small enough to support both multimedia and control applications.
The Use of a Neural Factory to Investigate the Effect of Product Line Width on Manufacturing Performance
Authors: Paul M. Swamidass, Satish S. Nair, Sanjay I. Mistry
Venue: Management Science (1999)

The dual goals of this study are: (1) to develop an empirically valid neural model of U.S. factories in a range of industries producing discrete products, and (2) to use the model to test the effect of changes in product line width on plant performance variables. Accordingly, a neural factory was developed using 59 input and 5 output/performance variables, and was trained using field data collected from 385 U.S. manufacturing plants. The model was validated using a holdout sample before conducting sensitivity tests. The study demonstrates that, through the use of parametric sensitivity analysis, the neural factory could be used to investigate the relationship between inputs and performance of a factory. While the focused factory principle would favor a smaller product line, economies of scope theory would favor a larger product line for the good of the factory; this implies a rather complex relationship between product line width (PLW) and plant performance. The neural factory was used to study the sensitivity of output/performance variables when product line width was varied over a range extending from 10% to 200% of the average values. The sensitivity analysis of the neural factory shows that, as the product line increases, it (1) does not affect cost-of-goods-sold (COGS), (2) decreases return on investment, (3) has a negative effect on the top management's perception of manufacturing performance, (4) increases inventory turns, and (5) increases sales per employee. The explanations for these findings show how complex and intertwined the relationships between PLW and performance variables are. They enhance our understanding of PLW and provide some new directions for future empirical research.
Multiresolution Based on Weighted Averages of the Hat Function I: Linear Reconstruction Techniques
Authors: Francesc Aràndiga, Rosa Donat, Ami Harten
Venue: SIAM Journal on Numerical Analysis (1998)

In this paper we analyze a particular example of the general framework developed in [A. Harten, {\it SIAM J. Numer. Anal}., 33 (1996) pp. 1205--1256], the case in which the discretization operator is obtained by taking local averages with respect to the hat function. We consider a class of reconstruction procedures which are appropriate for this multiresolution setting and describe the associated prediction operators that allow us to climb up the ladder from coarse to finer levels of resolution. In Part I we use data-independent (linear) reconstruction techniques as our approximation tool. We show how to obtain multiresolution transforms in bounded domains and analyze their stability with respect to perturbations.
Quality Determination for Gate Delay Fault Tests Considering Three-State Elements
Authors: Frank Pöhl, Walter Anheier
Venue: Journal of Electronic Testing: Theory and Applications (1999)

Most industrial digital circuits contain three-state elements besides pure logic gates. This paper presents a gate delay fault simulator for combinational circuits that can handle three-state elements like bus drivers, transmission gates and pulled busses. The well known delay faults&mdash;&ldquo;slow-to-rise&rdquo; and &ldquo;slow-to-fall&rdquo;&mdash;are considered as well as delayed transitions from isolating signal state &ldquo;high impedance&rdquo; to binary states &lsquo;0&rsquo; and &lsquo;1&rsquo; and vice versa. The presented parallel delay fault simulator distinguishes between non-robust, robust and hazard free tests and determines the quality of a test. Experimental results for ISCAS85/89 benchmark circuits are presented as well as results for industrial circuits containing three-state elements.
Supporting Cost-Effective Fault Tolerance in Distributed Message-Passing Applications with File Operations
Authors: Jinsong Ouyang, Piyush Maheshwari
Venue: The Journal of Supercomputing (1999)

In this paper we present an approach to reliable distributed computing, which incorporates fault tolerance into applications at low cost, in terms of both run-time performance and programming effort required to construct reliable application software. In our model fault tolerance is based on distributed consistent checkpointing and rollback-recovery integrated with a user-level reliable transmission protocol. By employing novel techniques 8and algorithms, our approach is distinguished from other consistent checkpointing schemes by the following features: first, minimum communication overhead for constructing a consistent distributed checkpoint and catching messages in transit during checkpointing; second, tolerance to message losses due to site failures or unreliable non-FIFO networks; and third, efficient checkpointing and recovery of persistent state, i.e., user files. Based on the model, a software library prototype called Libra has been implemented for supporting fault tolerance in distributed message-passing applications with file operations. The library provides an easy to use programming interface including message-passing and file I/O primitives, which hides the complexity of both fault-tolerant network communications and checkpointing and recovering user files from the application level. Experience with a number of long-running distributed applications shows that Libra can provide fault tolerance in a cost-effective manner.
Efficient Arithmetic on Koblitz Curves
Authors: Jerome A. Solinas
Venue: Designs, Codes and Cryptography (2000)

It has become increasingly common to implement discrete-logarithm based public-key protocols on elliptic curves over finite fields. The basic operation is scalar multiplication: taking a given integer multiple of a given point on the curve. The cost of the protocols depends on that of the elliptic scalar multiplication operation.Koblitz introduced a family of curves which admit especially fast elliptic scalar multiplication. His algorithm was later modified by Meier and Staffelbach. We give an improved version of the algorithm which runs 50 than any previous version. It is based on a new kind of representation of an integer, analogous to certain kinds of binary expansions. We also outline further speedups using precomputation and storage.
Self-adapting Fortran 77 machine constants: comment on Algorithm 528
Authors: David M. Gay, Eric Grosse
Venue: ACM Transactions on Mathematical Software (TOMS) (1999)

This note discusses user dissatisfaction with the need to uncomment data statements in Algorithm 528, comments on alternative approaches tried by the community, and proposes a solution that is both automatic and safe.
Compuational analyses of developmental cis-regualtory control systems (invited presentation)
Authors: Eric Davidson
Venue: Proceedings of the fourth annual international conference on Computational molecular biology (2000)

Developmental processes are hardwired in the genomic DNA of each animal species. The DNA sequences that specify the architecture of developmental control networks are the cis-regulatory elements that individually determine the state of activity of each of the many genes required to generate a developmental event. These elements each mediate many interactions with transcription factors, which are selected with high specificity according to the target binding sites in each cis-regulatory element. Cis-regulatory elements can be thought of as analog information processing devices. This concept is illustrated by an experimental and computational analysis of a cis-regulatory system from the developmentally regulated Endo 16 gene of the sea urchin embryo. Large-scale developmental events require mobilization of batteries of downstream genes, and are instituted by signal inputs to regulatory genes encoding transcription factors. Functional linkages between genes determine which signals affect which regulatory genes, in space and time, and which gene batteries will be involved. Thus both inter cis-regulatory networks and intra cis-regulatory systems are specified by arrays of genomic target site sequences. A model of an intergenic network of this kind that controls endomesoderm specification in sea urchin embryos has been constructed on the basis of experimental information. This model consists of a set of predicted inputs and outputs to a minimal group of regulatory genes encoding endodermal and mesodermal transcription factors, and components of signaling systems. The predictions of the model are experimentally testable, and indeed some such model is a clear necessity for productive experimental analysis. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player