ppxscal/embedding_network huggingface dataset:
Approximating An Optimal Production Policy in a Continuous Flow Line: Recurrence and Asymptotic Properties
Authors: Houmin Yan, Xun Yu Zhou, G. Yin
Venue: Operations Research (1999)

This work is concerned with manufacturing systems with two failure-prone tandem machines. The production is regulated by a continuous version of buffer control. Our goal is to obtain an optimal buffer-control policy to minimize a long-run average cost function. Concentrating on threshold type of control policies, our effort is devoted to parameter optimization problems for the continuous material produce-to-stock models. We estimate the gradients of the cost function with respect to the parameter using perturbation analysis techniques, and approximate the optimal value of the parameter via a constant step-size stochastic approximation algorithm. An analysis for error accumulation in perturbation propagation is undertaken, and a sufficient condition for breaking the propagation chain is derived. In addition, we show that the event of breaking the perturbation propagation chain is recurrent if the system has sufficient capacity, derive the consistency of the gradient estimators, and establish the convergence of the iterative algorithm. We also treat non-Markovian models with the machine repair time following an Erlang distribution, and provide numerical examples to illustrate the proposed algorithm.
Microarchitectural denial of service: insuring microarchitectural fairness
Authors: Dirk Grunwald, Soraya Ghiasi
Venue: Proceedings of the 35th annual ACM/IEEE international symposium on Microarchitecture (2002)

Simultaneous multithreading seeks to improve the aggregate computation bandwidth of a processor core by sharing resources such as functional units, caches, TLB and so on. To date, most research investigating the scheduling of these shared resources has focused on enhancing computational bandwidth. In this paper, we examine scheduling fairness. First, we show that a thread running on an implementation of a SMT processor can suffer from "denial of service" by a malicious thread, slowing down the original thread by a factor of 10--20. Using performance counter hardware, we show that the slowdown occurs because of deliberate misuse of shared resources and design decisions that are necessary for high speed implementation.We then propose and evaluate a number of mechanisms to counter such malicious behavior: some affect the core scheduling algorithm and others simply attempt to identify activity that would affect threads sharing the same processor core. We find that harmful activity based mechanisms outperform core scheduling mechanisms. In addition, we show that they can be designed so that they can differentiate between malicious attacks and legitimate activities that may also make use of the same harmful activities.
An application with variations as used in teaching a Palm programming course
Authors: W. Douglas Maurer
Venue: Journal of Computing Sciences in Colleges (2003)

Handheld devices such as the Palm are becoming common in the modern world. Since the Palm is programmed in C, and since computer science departments teach C, it is natural to set up a course in which students learn how to program for the Palm. However, even the simplest application for the Palm is far longer than a simple application for a personal computer. In this paper we introduce an application with a large number of variations, each of which illustrates a different feature of the Palm (buttons, checkboxes, push buttons, popup triggers, selector triggers, and the like). The text of all these variations is available from the author. Besides being a simple and interesting Palm application, our example is of considerable utility in the design of other applications.
Assessment of the complexity/regularity of transient brain waves (EEG) during sleep, based on wavelet theory and the concept of entropy
Authors: M. Mikaili, S. M. R. Hashemi Golpayegani
Venue: Iranian Journal of Science and Technology (2002)

In this paper we describe a new approach to quantify the concepts of order and complexity of EEG signals during sleep. Based on the concepts of entropy and wavelet transform, we introduce a measure named Wavelet-Entropy and we will show the results of its application to real sleep EEG signals and artificial data. The definition of wavelet entropy is very similar to the definition of entropy in information theory or spectral entropy in signal processing but its most important difference is the usage of time-frequency representation of the signal and its wavelet coefficients. Time-frequency methods proved to be very useful for signals like EEG with fast changing dynamics and high non-stationarity. This characteristic of EEG limits the usage of other complexity evaluation methods like chaos analysis and parameters like correlation dimension or Lyapunov exponent.
Comparing smart card adoption in Singapore and Australian universities
Authors: Catherine Hui Min Lee, Yuk Wing Cheng, Arnold Depickere
Venue: International Journal of Human-Computer Studies (2003)

College and university environments offer one of the best opportunities for the adoption of smart card technology. This study explores the possibility of developing smart card as a university application and investigates whether it will help to reduce the university business administration procedures as well as increase their service efficiency. This involved investigating the response of two groups (experienced and non-experienced) towards the adoption or the intention to embrace the technology of a university smart card. Studying the experiences gained by Nanyang Technological University (NTU, Singapore) students using smart card application in their university may provide an insightful picture for a university that is considering adopting such a technological innovation.Results show that compatibility pre-adoption construct is the key element that plays the most influential factor in motivating local students for adoption. This suggests that to ensure adoption, it is important to guarantee that the university smart cards are socially acceptable among the university students (fit well with the students' norm and environment). Another implication of this study is that Murdoch University (MU, Australia) students would most probably be willing to accept the adoption of a university smart card given that the results show MU students' response of (probability= 168/200) and NTU students' response of 100% (probability= 50/50) acceptance toward using their university smart card. The results also show a significant culture difference between MU students and NTU students, indicating that smart card manufacturer should take note of the ranking of user preference when designing a university smart card in order to optimize the adoption process.
Business Planning for Network Services: A Systems Thinking Approach
Authors: Amitava Dutta
Venue: Information Systems Research (2001)

As demand for online network services continues to grow, service providers are looking to meet this need and avail themselves of business opportunities. However, despite strong growth in demand, providers continue to have difficulty achieving profitability, customer churn remains high, and network performance continues to draw complaints. We suggest that strategic business planning for network services would benefit from a systems thinking approach that analyzes thefeedback effects present in the underlying business process. These feedback loops can be complex and have significant impact on business performance. For instance, while the size of a provider's customer base depends on price and network performance, network performance is itself dependent on the size of the customer base. In this paper, we develop a planning model that represents thesefeedback effects using the finite difference equations methodology of systems dynamics. The model is validated by showing its fit with essential characteristics of the underlying problem domain, and by showing its ability to replicate observed reference mode behaviors. Simulations are then carried out under a variety of scenarios to examine issues important to service providers. Among other findings, the simulations suggest that (a) under flat-rate pricing, lowering price to increase customer base can hurt profitabilityas well as network performance; (b) under usage-based pricing, lowering price need not necessarily lead to a larger customer base; and Â© in addition to price, the customers' threshold of tolerance for performance degradation plays a significant role in balancing market share with profitability. We briefly present a prototype decision support system based on the systems thinking approach, and suggest ways in which it could be used to help business planning for network services.
Termination of on-demand rewriting and termination of OBJ programs
Authors: Salvador Lucas
Venue: Proceedings of the 3rd ACM SIGPLAN international conference on Principles and practice of declarative programming (2001)

Declarative languages such as OBJ, CafeOBJ, and Maude use syntactic annotations to introduce replacement restrictions aimed at improving termination or efficiency of computations. Unfortunately, there is a lack of formal techniques for proving such benefits. We show that context-sensitive rewriting and on-demand rewriting provide a suitable framework to address this problem. We provide methods to analyze termination of on-demand rewriting and apply them to analyze termination of OBJ, CafeOBJ, and Maude programs.
Top-down decision tree learning as information based boosting
Authors: Eiji Takimoto, Akira Maruoka
Venue: Theoretical Computer Science (2003)

We consider a boosting technique that can be directly applied to multiclass classification problems. Although many boosting algorithms have been proposed so far, most of them are developed essentially for binary classification problems, and in order to handle multiclass classification problems, they need to be reduced somehow to binary ones. In order to avoid such reductions, we introduce a notion of the pseudo-entropy function G that gives an information-theoretic criterion, called the conditional G-entropy, for measuring the loss of hypotheses. The conditional G-entropy turns out to be useful for defining the weakness of hypotheses that approximate, in some way, a multiclass function in general, so that we can consider the boosting problem without reduction. We show that the top-down decision tree learning algorithm using the conditional G-entropy as its splitting criterion is an efficient boosting algorithm. Namely, the algorithm intends to minimize the conditional G-entropy, rather than the classification error. In the binary case, our algorithm turns out to be identical to the error-based boosting algorithm proposed by Kearns and Mansour, and our analysis gives a simpler proof of their results.
On the stationary flow of a waxy crude oil with deposition mechanisms
Authors: Lorenzo Fusi
Venue: Nonlinear Analysis: Theory, Methods Applications (2003)

In this paper we will present a model for the flow of a waxy crude oil in a test loop, taking into account deposition mechanisms due to the high content of paraffin. We will analyse the flow in a non-isothermal condition considering the main rheological parameters depending on the radial coordinate of the pipe. We will formulate the related mathematical problem, which will turn out to be a free boundary problem, and perform a quasi-steady approximation for some of the equations involved. For such approximated problem well posedness is proved.
Survival Analysis Methods for Personal Loan Data
Authors: Maria Stepanova, Lyn Thomas
Venue: Operations Research (2002)

Credit scoring is one of the most successful applications of quantitative analysis in business. This paper shows how using survival-analysis tools from reliability and maintenance modeling allows one to build credit-scoring models that assess aspects of profit as well as default. This survival-analysis approach is also finding favor in credit-risk modeling of bond prices. The paper looks at three extensions of Cox's proportional hazards model applied to personal loan data. A new way of coarse-classifying of characteristics using survival-analysis methods is proposed. Also, a number of diagnostic methods to check adequacy of the model fit are tested for suitability with loan data. Finally, including time-by-characteristic interactions is proposed as a way of possible improvement of the model's predictive power.
Dynamic shortest path in stochastic dynamic networks
Authors: A. Azaron, F. Kianfar
Venue: Iranian Journal of Science and Technology (2001)

This paper develops an algorithm for finding the dynamic shortest path from the source node to the sink node in stochastic dynamic networks, in which the arc lengths are independent random variables with exponential distributions. In each node there is an environmental variable, which evolves in accordance with a continuous time Markov process. The parameter of the exponential distribution of the transition time of each arc is also a function of the state of the environmental variable of its initiating node. It is also assumed that upon arriving at each node, we know the state of its environmental variable and also the states of the environmental variables of its adjacent nodes. Upon arriving at each node, we can move toward the sink node through the best outgoing arc or wait for encountering the better state of its environmental variable, which reduces the expected transition times of the outgoing arcs. In this paper, we apply the stochastic dynamic programming for finding the dynamic shortest path from the source node to the sink node by obtaining the optimal strategy of movement in each node of the network.
Parallel execution time analysis for least squares problems on distributed memory architectures
Authors: Laurence Tianruo Yang, Richard P. Brent
Venue: Practical parallel computing (2001)

In this paper we study the parallelization of PCGLS, a basic iterative method which main idea is to organize the computation of conjugate gradient method with preconditioner applied to normal equations. Two important schemes are discussed. What is the best possible data distribution and which communication network topology is most suitable for solving least squares problems on massively parallel distributed memory computers. A theoretical model of data distribution and communication phases is presented which allows us to give a detail execution time complexity analysis and to investigate its usefulness. It is shown that the implementation of PCGLS, with a row-block decomposition of the coefficient matrix, on a ring of communication structure is the most efficient choice. Performance tests of the developed parallel PCGLS algorithm have been carried out on the massively distributed memory system Parsytec and experimental timing results are compared with the theoretical execution time complexity analysis.
Long-Term Forest Ecosystem Planning at Pacific Lumber
Authors: L. Russell Fletcher, Henry Alden, Scott P. Holmen, Dean P. Angelides, Matthew J. Etzenhouser
Venue: Interfaces (1999)

In 1995, the Pacific Lumber Company contracted with VESTRA Resources to develop a 120-year, 12-period forest-eco system management plan for its properties to meet new California Board of Forestry wildlife, fisheries, and timber resource requirements and to optimize its timberland operations and profitability. VESTRA Resources developed the ecosystem planning express model, Ep(x), which seamlessly integrates geographic information systems with a database resource capability model and a policy-alternative model, providing the inputs to a linear program. The Ep(x) model uses an underlying adaptive management approach that also maximizes the knowledge base of the ecosystem through detailed sensitivity analyses. The model increased present net worth by over $398 million and generated a more optimal mix of wildlife habitat acres, including spotted-owl-nesting habitat.
On 2-arc-transitivity of Cayley graphs
Authors: Dragan Marušič
Venue: Journal of Combinatorial Theory Series B (2003)

The classification of 2-arc-transitive Cayley graphs of cyclic groups, given in (J. Algebra. Combin. 5 (1996) 83- 86) by Alspach. Conder, Xu and the author, motivates the main theme of this article: the study of 2-arc-transitive Cayley graphs of dihedral groups. First, a previously unknown infinite family of such graphs, arising as covers of certain complete graphs, is presented, leading to an interesting property of Singer cycles in the group PGL(2, q), q an odd prime power, among others. Second, a structural reduction theorem for 2-arc-transitive Cayley graphs of dihedral groups is proved, putting us--modulo a possible existence of such graphs among regular cyclic covers over a small family of certain bipartite graphs--a step away from a complete classification of such graphs. As a byproduct, a partial description of 2- arc-transitive Cayley graphs of abelian groups with at most three involutions is also obtained.
Integrated design method for flip chip CSP with electrical, thermal and thermo-mechanical qualifications
Authors: De-Shin Liu, Chin-Yu Ni, Ching-Yang Chen
Venue: Finite Elements in Analysis and Design (2003)

A new design method involving electrical, thermal and thermo-mechanical characterizations was developed to optimize the geometric parameters and material properties of a flip chip CSP. A two-dimensional nonlinear finite element model was created using the APDL commercial software ANSYS programming technique to connect with the search routines of genetic algorithms. The electrical characterization optimization objective function was used to set the characteristic impedance of the solder bump and corresponded with the first incident voltage adapting the CMOS switch event to reduce the response time delay in the binary command as well as maintaining the chip level efficiency. The thermal resistance determines the package thermal performance; that is, the objective function is to minimize the thermal resistance under certain power dissipation parameters. Thermally induced stress and warpage dominate the thermo-mechanical behavior. The objective function is the minimization of the thermal stress gradients around the chip, bump, underfill and molding compound as well as mechanical warpage in the entire package. The optimization results show that a remarkable strategy for packaging design was achieved.
A Scale Adaptive Method for Estimating the Perspective Pose of Texture Planes
Authors: Eraldo Ribeiro, Edwin R. Hancock
Venue: Proceedings of the XII Brazilian Symposium on Computer Graphics and Image Processing (1999)

Multiple vanishing point detection provides the key to recovering the perspective pose of textured planes. If vanishing points are to be detected from spectral information then there are two computational problems that need to be solved. Firstly, the search of the extended image plane is unbounded, and hence the location of vanishing points at or near infinity is difficult. Secondly, correspondences between local spectra need to be established so that vanishing points can be triangulated. In this paper we offer a way of overcoming these two difficulties. We overcome the problem of unbounded search by mapping the information provided by local spectral moments onto the unit-sphere. According to our representation, the position and direction of each local spectrum maps onto a great circle on the unit-sphere. The need for correspondences is overcome by accumulating the great circle intercepts. Vanishing points occur at local accumulator maxima on the unit sphere. To improve the accuracy of the recovered perspective pose parameters for highly slanted planes, we use an adaptive spectral window. This selects the window so as to reduce spectral defocussing by minimizing the determinant of the spectral covariance matrix. We experiment with the new shape-from-texture technique on both synthetic and real world data. Here it proves to be an accurate and robust means of estimating perspective pose.
The mutual exclusion scheduling problem for permutation and comparability graphs
Authors: Klaus Jansen
Venue: Information and Computation (2003)

In this paper, we consider the mutual exclusion scheduling problem for comparability graphs. Given an undirected graph G and a fixed constant m, the problem is to find a minimum coloring of G such that each color is used at most m times. The complexity of this problem for comparability graphs was mentioned as an open problem by Möhring [Problem 9.10, in: I. Rival (Ed.), Graphs and Orders, Reidel, Dordrecht, 1985, p. 583] and for permutation graphs (a subclass of comparability graphs) as an open problem by Lonc [On complexity of some chain and antichain partition problem, in: G. Schmidt, R. Berghammer (Eds.), Graph Theoretical Concepts in Computer Science, WG 91, Lecture Notes in Computer Science, vol. 570, 1999, pp. 97-104]. We prove that this problem is already NP-complete for permutation graphs and for each fixed constant m ≥ 6.
War and Peace: The First 25 Years of or in Great Britain
Authors: K. Brian Haley
Venue: Operations Research (2002)

This paper identifies a number of events and circumstances, which contributed in Great Britain during the period 1938--1963 to the development and adoption of OR outside the military and defence concerns. I show how the OR club formed a focus for industrial activity and the development of the subject. The early growth in education and training provision will also be traced to indicate its influence on the direction of OR and its acceptance as an academic discipline.
Economic statistical design of X control charts for systems with gamma(&#x03BB;, 2) in-control times
Authors: Hajaj A. Al-Oraini, M. A. Rahim
Venue: Computers and Industrial Engineering (2002)

In this paper, Gamma(λ,2) distribution is considered as a failure model for the economic statistical design of X control charts. The study shows that the statistical performance of control charts can be improved significantly, with only a slight increase in the cost, by adding constraints to the optimization problem. The use of an economic statistical design instead of an economic design results in control charts that may be less expensive to implement, that have lower false alarm rates, and that have a higher probability of detecting process shifts. Numerical examples are presented to support this proposition. The results of economic statistical design are compared to those of a pure economic design. The effects of adding constraints for statistical performance measures, such as Type I error rate and the power of the chart, are extensively investigated.
Mixed finite volume methods on nonstaggered quadrilateral grids for elliptic problems
Authors: So-Hsiang Chou, Do Y. Kwak, Kwang Y. Kim
Venue: Mathematics of Computation (2003)

We construct and analyze a mixed finite volume method on quadrilateral grids for elliptic problems written as a system of two first order PDEs in the state variable (e.g., pressure) and its flux (e.g., Darcy velocity). An important point is that no staggered grids or covolumes are used to stabilize the system. Only a single primary grid system is adopted, and the degrees of freedom are imposed on the interfaces. The approximate flux is sought in the lowest-order Raviart-Thomas space and the pressure field in the rotated-Q1 nonconforming space. Furthermore, we demonstrate that the present finite volume method can be interpreted as a rotated-Q1 nonconforming finite element method for the pressure with a simple local recovery of flux. Numerical results are presented for a variety of problems which confirm the usefulness and effectiveness of the method
Cliques in dense GF(q)-representable matroids
Authors: James Geelen, Geoff Whittle
Venue: Journal of Combinatorial Theory Series B (2003)

We prove that, for any finite field F and positive integer n, there exists an integer λ such that if M is a simple F-representable matroid with no M(Kn)-minor, then |E(M)|≥λr(M).