ppxscal/embedding_network huggingface dataset:
Distributed credential chain discovery in trust management
Authors: Ninghui Li, William H. Winsborough, John C. Mitchell
Venue: Journal of Computer Security (2003)

We introduce a simple Role-based Trust-management language RT0 and a set-theoretic semantics for it. We also introduce credential graphs as a searchable representation of credentials in RT0 and prove that reachability in credential graphs is sound and complete with respect to the semantics of RT0. Based on credential graphs, we give goal-directed algorithms to do credential chain discovery in RT0, both when credential storage is centralized and when credential storage is distributed. A goal-directed algorithm begins with an access-control query and searches for credentials relevant to the query, while avoiding considering the potentially very large number of credentials that are unrelated to the access-control decision at hand. This approach provides better expected-case performance than bottom-up algorithms. We show how our algorithms can be applied to SDSI 2.0 (the 'SDSI' part of SPKI/SDSI 2.0).Our goal-directed, distributed chain discovery algorithm finds and retrieves credentials as needed. We prove that the algorithm is correct by proving that the algorithm is sound and complete with respect to the credential graph composed of the credentials it retrieves, and that the algorithm retrieves all credentials that constitute a traversable chain. We further introduce a storage type system for RT0, which guarantees traversability of chains when credentials are well typed. This type system can also help improve search efficiency by guiding search in the right direction, making distributed chain discovery with large number of credentials feasible.
Verifying minimum stable circuit values
Authors: C. K. Poon
Venue: Information Processing Letters (2003)

We study properties of the minimum stable circuit value of a certain class of arithmetic circuits and describe a polynomial time algorithm that checks if a given circuit value is minimum stable for any such circuit.
A prototype multilingual document browser for ancient Greek texts
Authors: Jeffrey A. Rydberg-Cox
Venue: The New Review of Hypermedia and Multimedia (2002)

This paper describes a prototype multilingual keyword extraction and information browsing system for texts written in Classical Greek. This system automatically extracts keywords from Greek texts using a tf x idf keyword discovery routine, clusters documents into thematically coherent groups based on these keywords, translates the keywords into English, and presents this information in two different formats so that users with limited knowledge of Ancient Greek can browse the documents and orient themselves to important concepts in the collections of a digital library.
Density-driven compaction and temperature evolution in porous media
Authors: Xin-She Yang
Venue: Applied Mathematics and Computation (2002)

Compactional flow and temperature evolution in porous media is modelled as a two-phase deformation process. The mathematical model leads to a pair of nonlinear diffusion equations with a moving boundary. Two distinguished features of density-driven compaction and temperature profile are then analysed and different styles of behaviour are compared and shown in this paper.
Stable adaptive control of fuzzy dynamic systems
Authors: G. Feng, S. G. Cao, N. W. Rees
Venue: Fuzzy Sets and Systems (2002)

This paper discusses fuzzy model reference adaptive control for a class of nonlinear systems. The system concerned is represented by a family of local transfer function models smoothly connected together by fuzzy membership functions. The model reference adaptive control law is first designed in each local region and then constructed in global domain. It is shown that the resulting fuzzy adaptive control system is globally stable based on a suitable piecewise differentiable Lyapunov function. A simulation example is given for demonstration of the application of the method.
Phoneme recognition using wavelet based features
Authors: O. Farooq, S. Datta
Venue: Information Sciences&mdash;Informatics and Computer Science: An International Journal (2003)

This paper proposes the use of the discrete wavelet transform (DWT) for the extraction of features from phonemes. Instead of using the short time Fourier transform for feature extraction a new set of features is obtained from the DWT. The new set of features overcomes the previously reported problem of shift variance in DWT based features. Training and test samples of the phonemes were obtained from the TIMIT database. To account for the fast changes in the phonemes, the features were calculated for different phoneme durations and the performance was compared. For the classification of the phonemes, two different classifiers were used, based on linear discriminant analysis and multi-layer perceptron.
Hardware-software bipartitioning for dynamically reconfigurable systems
Authors: Daler N. Rakhmatov, Sarma B. K. Vrudhula
Venue: Proceedings of the tenth international symposium on Hardware/software codesign (2002)

The main unique feature of dynamically reconfigurable systems is the ability to time-share the same reconfigurable hardware resources. However, the energy-delay cost associated with reconfiguration must be accounted for during hardware-software partitioning. We propose a method for mapping nodes of an application control flow graph either to software or reconfigurable hardware, explicitly targeting minimization of the energy-delay cost due to both computation and configuration. The addressed problems are energy-delay product minimization, delay-constrained energy minimization, and energy-constrained delay minimization. We show how these problems can be tackled by using network flow techniques, after transforming the original control flow graph into an equivalent network. If there are no constraints, as in the case of the energy-delay product minimization, we are able to generate an optimal solution in polynomial time.
Partial evaluation of pattern matching in strings, revisited
Authors: Bernd Grobauer, Julia L. Lawall
Venue: Nordic Journal of Computing (2001)

Specialization of a string matcher is a canonical example of partial evaluation. A naive implementation of a string matcher repeatedly matches a pattern against every substring of the data string; this operation should intuitively benefit from specializing the matcher with respect to the pattern. In practice, however, producing an efficient implementation by performing this specialization using standard partial-evaluation techniques requires non-trivial binding-time improvements. Starting with a naive matcher, we thus present a derivation of such a binding-time improved string matcher. We show that specialization with respect to a pattern yields a matcher with code size linear in the length of the pattern and a running time independent of the length of the pattern and linear in the length of the data string. We then consider several variants of matchers that specialize well, amongst them the first such matcher presented in the literature, and we demonstrate how variants can be derived from each other systematically.
Effect of aspect ratio on three-dimensional natural convection in a horizontal enclosure with a uniform heat flux on the lower surface
Authors: P. H. Oosthuizen
Venue: Scientific computing and applications (2001)

Flow in a rectangular enclosure with horizontal upper and lower walls and vertical side walls and with a uniform heat flux applied across the lower horizontal surface and with the upper horizontal surface cooled to a uniform low temperature has been numerically studied. The length of one side of the horizontal cross-section is equal to the height of the enclosure while the length of the other side is in general different from the height of the enclosure. The enclosure aspect ratio is here defined as the ratio of the lengths of the sides of the horizontal cross-section. The vertical side-walls of the enclosure are adiabatic. It has been assumed that the flow is laminar and that the fluid properties are constant except for the density change with temperature which gives rise to the buoyancy forces. The unsteady forms of the dimensionless governing equations have been solved using a finite-difference procedure. The solution, in general, has the following parameters: the heat flux Rayleigh number, the Prandtl number and the aspect ratio of the horizontal cross-sectional shape. Results have only been obtained for a Prandtl number of 0.7, for Rayleigh number of up to 30000 and for aspect ratios of between 0.5 and 3. The results have been used to determine the effect of the governing parameters on the conditions under which fluid motion develops in the enclosure and to examine the flow patterns that arise in the enclosure.
Incentives and Computing Systems for Team-Based Organizations: A Mathematical and Economic Analysis
Authors: Ugo Merlone
Venue: Organization Science (2002)

This paper provides a mathematical and economic analysis "Incentives and Computing Systems for Team-Based Organizations" by A. Barua, C. H. Sophie Lee, and A. B. Whinston, which was published in Organization Science in 1995. Several points were not adequately stated in the original article and one of the key definitions is not clear, nor is it in keeping with the classical theory of production. Although the Cobb-Douglas production function is often used in the article, it does not comply with the article's definitions. The two main contributions of this paper are (1) to provide a word of caution to other readers who might try to extend Barua et al. (1995) and (2) to suggest alternative formulations and directions for future research.
Organizational Capabilities in Product Development of Japanese Firms: a Conceptual Framework and Empirical Findings
Authors: Ken Kusunoki, Ikujiro Nonaka, Akiya Nagata
Venue: Organization Science (1998)

Using a large-scale data set on product development organizations of Japanese manufacturing firms, this paper explores the effects of organizational capabilities on product development performance. We present a conceptual framework assuming that organizational capabilities consist of multilayered knowledge. Based on the idea, we classify organizational capabilities into "local," "architectural," and "process" capabilities along two dimensions: modularity and designability. The empirical analysis demonstrates differential effects of different types of organizational capabilities on different types of product development performance, and compares the differential effects between two types of industries that differ in terms of their product characteristics: system based and material based. The central message from our analysis is that the process capabilities emerging from dynamic interaction of knowledge play a crucial role as core capabilities for product development of Japanese firms in the system-based industries in which Japanese firms are relatively competitive. In the material industries, ho wever, local capabilities have major effects on performance while effects of process capabilities are limited, which underlies the relative weakness of Japanese firms in developing material-based products. Our results raise some intriguing implications on the competitive advantages and challenges of Japanese firms' product development.
A Chebyshev set and its distance function
Authors: Zili Wu
Venue: Journal of Approximation Theory (2002)

We prove that in a Banach space X with rotund dual X* a Chebyshev set C is convex iff the distance function dc is regular on X/C iff dc admits the strict and Gâteaux derivatives on X\C which are determined by the subdifferential ∂||x - x'|| for each x ∈ X\C and x'\c Pc(x) := {c ∈ C:||x - c|| = dc(x)}. If X is a reflexive Banach space with smooth and Kadec norm then C is convex iff it is weakly closed iff Pc is continuous. If the norms of X and X* are Fréchet differentiable then C is convex iff dc is Fréchet differentiable on X\C. If also X has a uniformly Gâteaux differentiable norm then C is convex iff the Gâteaux (Fréchet) subdifferential ∂-dc (x) (∂Fdc(x)) is nonempty on X\C.
Detection of Invalid Routing Announcement in the Internet
Authors: Xiaoliang Zhao, Dan Pei, Lan Wang, Dan Massey, Allison Mankin, Shyhtsun Felix Wu, Lixia Zhang
Venue: Proceedings of the 2002 International Conference on Dependable Systems and Networks (2002)

Network measurement has shown that a specific IP address prefix may be announced by more than one autonomous system (AS), a phenomenon commonly referred to as Multiple Origin AS, or MOAS. MOAS can be due to either operational need to support multi-homing, or false route announcements due to configuration or implementation errors, or even by intentional attacks. Packets following such bogus routes will be either dropped or, in the case of an intentional attack, delivered to a machine of the attacker's choosing.This paper presents a protocol enhancement to BGP which enables BGP to detect bogus route announcements from false origins. Rather than imposing cryptography-based authentication and encryption to secure routing message exchanges, our solution makes use of the rich connectivity among ASes that exists in the Internet. Simulation results show that this simple solution can effectively detect false routing announcements even in the presence of multiple compromised routers, become more robust in larger topologies, and can substantially reduce the impact of false routing announcements even with a partial deployment.
The congenial talking philosophers problem in computer networks
Authors: Yuh-Jzer Joung
Venue: Distributed Computing (2002)

Group mutual exclusion occurs naturally in situations where a resource can be shared by processes of the same group, but not by processes of different groups. For example, suppose data is stored in a CD-jukebox. Then when a disc is loaded for access, users that need data on the disc can concurrently access the disc, while users that need data on a different disc have to wait until the current disc is unloaded.The design issues for group mutual exclusion have been modeled as the Congenial Talking Philosophers problem, and solutions for shared-memory models have been proposed [12, 14]. As in ordinary mutual exclusion and many other problems in distributed systems, however, techniques developed for shared memory do not necessary apply to message passing (and vice versa). So in this paper we investigate solutions for Congenial Talking Philosophers in computer networks where processes communicate by asynchronous message passing. We first present a solution that is a straightforward adaptation from Ricart and Agrawala's algorithm for ordinary mutual exclusion. Then we show that the simple modification suffers a severe performance degradation that could cause the system to behave as though only one process of a group can be in the critical section at a time. We then Present a more efficient and highly concurrent distributed algorithm for the problem, the first such solution in computer networks.
Continued fractions and integrable systems
Authors: Richard Beals, David H. Sattinger, Jacek Szmigielski
Venue: Journal of Computational and Applied Mathematics (2003)

Stieltjes' solution of the classical moment problem is the forerunner of inverse spectral theory. In the modern theory of completely integrable systems, the method of inverse scattering is used to obtain explicit solutions of a class of Hamiltonian systems which arise as isospectral deformations of a linear operator. In this lecture we explain how Stieltjes's formulas are used to obtain explicit solutions to a number of completely integrable systems, including discrete reductions of some nonlinear partial differential equations, and the isospectral deformations of Jacobi matrices a.k.a. Toda flows.
Sensitivity of traffic emissions over the Iberian Peninsula by using MM5-CMAQ air quality modelling system
Authors: R. San José, J. L. Pérez, F. Blanco, R. Barquín, R. M. González
Venue: Development and application of computer techniques to environmental studies (2002)

The continuous increase on the vehicle fleet in Europe is contributing in a very significant portion to total emission budget particularly over cities with high population density. The ozone concentrations are particularly sensitivity to NOX and VOC's emissions produced by vehicle traffic. The importance of long range transport on urban ozone concentrations is a task subject to heavy research in the last years since urban emission reduction strategies seem to impact on ozone concentration reductions lower than expected. The impact of long range transport is becoming more and more important to explain the resistance to ozone concentrations to be reduced by taking into account only local vehicle traffic emission reductions strategies. In this contribution we have used the MM5 (PSU/NCAR) meteorological model and CMAQ (EPA, U.S.) air quality modelling system to simulate the impact of NOx emissions due to vehicle traffic (road traffic) on ozone concentrations over the Iberian Peninsula nesting over Madrid domain. The mother domain covers a 8100 km × 6480 km centered over the Iberian Peninsula but taking most of North of Africa and up to the North part of Norway. Three nesting levels are used up to Madrid Community level. High sensitivity of emission at Iberian Peninsula level (nesting level 1) are found.
Interactive feature specification for focus+context visualization of complex simulation data
Authors: Helmut Doleisch, Martin Gasser, Helwig Hauser
Venue: Proceedings of the symposium on Data visualisation 2003 (2003)

Visualization of high-dimensional, large data sets, resulting from computational simulation, is one of the most challenging fields in scientific viualization. When visualization aims at supporting the analysis of such data sets, feature-based approches are very useful to reduce the amount of data which is shown at each instance of time and guide the user to the most interesting areas of the data. When using feature-based visualization, one of the most difficult questions is how to extract or specify the features. This is mostly done (semi-)automatic up to now. Especially when interactive analysis of the data is the main goal of the visualization, tools supporting interactive specification of features are needed.In this paper we present a framework for fiexible and interactive specification of high-dimensional and/or complex features in simulation data. The framework makes use of multiple, linked views from information as well as scienti c visualization and is based on a simple and compact feature definition language (FDL). It allows the definition of one or several features, which can be complex and/or hierarchically described by brushing multiple dimensions (using non-binary and composite brushes). The result of the specification is linked to all views, thereby a focus+context style of visualization in 3D is realized. To demonstrate the usage of the specification, as well as the linked tools, applications from flow simulation in the automotive industry are presented.
A Capacitated Production-Inventory Model with Periodic Demand
Authors: Roman Kapuscinski, Sridhar Tayur
Venue: Operations Research (1998)

For a single product, single-stage capacitated production-inventory model with stochastic, periodic (cyclic) demand, we find the optimal policy and characterize some of its properties. We study the finite-horizon, the discounted infinite-horizon and the infinite-horizon average cases. A simulation based optimization method is provided to compute the optimal parameters. Based on a numerical study, several insights into the model are also provided.
Predicting user satisfaction from subject satisfaction
Authors: Margaret B. Swan, Mark Notess
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

In this paper, we describe work-in-progress in comparing user satisfaction ratings after user tests with ratings obtained following actual use of a digital music library software. We identify some of the variables that hamper prediction, and we reflect on the utility of surveys for predicting user/subject gaps in satisfaction.
The first known type (7,1) amicable pair
Authors: Mariano Garcia
Venue: Mathematics of Computation (2003)

Amicable pairs of type (i, 1) have been the object of special search partly because they breed other amicable pairs. Examples exist for i = 2, 3, 4, 5, and 6. In this paper we exhibit the first known type (7, 1) pair.
The Optimal Performance of the Global Firm: Formalizing and Extending the Integration- Responsiveness Framework
Authors: Timothy M. Devinney, David F. Midgley, Sunil Venaik
Venue: Organization Science (2000)

With the increasing globalization of business, there has been growing interest in how to create and manage a successful international enterprise. Although researchers and practitioners have grappled with the issue of globalization for some time, there is no one model that encompasses the range of phenomena we observe in the global economy, nor have those models that do exist been precisely formalized.This paper provides an expanded approach to thinking about the organizational forms and linkages that exist in international business operations. Building on the popular integrationresponsiveness framework of international strategic orientation, we develop a more expansive approach that is better able to account for the diversity of organizational forms and strategic choices open to managers. By adding a third set of environmental pressures, incorporating the beliefs of managers, and by employing the idea of efficient frontiers, we reformulate the integration-responsiveness framework, making it more consistent with modern economic models of the firm. Our integration-responsiveness-completeness (IRC) model argues that global firms can respond to these fundamental and competing pressures by configuring themselves in a variety of ways--rather than normatively prescribing that the transnational form is optimal. In addition, our model has methodological ramifications. Its formal structure suggests that empirical techniques that focus on the best rather than average performance are necessary to adequately investigate the performance differences among alternative organizational forms. This may explain the paradoxical lack of empirical support for a link between organizational form and performance.
Model modification in structural equation modeling by imposing constraints
Authors: Chih-Ping Chou, P. M. Bentler
Venue: Computational Statistics Data Analysis (2002)

Two approaches for model modification, or specification search, in structural equation modeling are: releasing constraints (e.g., adding free parameters) and imposing constraints (e.g., deleting free parameters). These two approaches can be considered as "forward search" and "backward search", respectively. The forward search approach, which starts with a more limited model to find a more general model by adding free parameters, is very frequently utilized in practice. However, the success rate of the forward approach in obtaining the correct model is usually low. The forward search also has been found to depend very highly on the initial model selected in the modification process. The farther the initial model differs from the true model, the less likely is the proper modification to occur. This study illustrates the backward search approach, which starts with a more general model and improves the model by imposing constraints, using the z and Wald (W) tests. Assuming a correct measurement model, this study focuses on the model modification of structural relationships among factors. The results showed that with correct specification of the causal order of latent factors the correct model may be located with higher than 60% accuracy, using the incremental univariate Wald test, or the z test. With more cautious, or restricted, search, the success rates are even higher.