Catálogo de publicaciones - libros

This study designed a system that prevents the leakage of information flowing through physical communication networks in ubiquitous computing environment. The information security system was designed from the viewpoint of information life cycle based on u-Office’ service scenario and, as a result, security holes were identified including indiscreet information access, malicious information leakage, unauthorized information alteration, illegal information retrieval, information leakage using various portable storage devices and printed-out information leakage. In addition, this study defined and designed essential security technology required to resolve these security holes.

In this paper, we introduce the design and implementation of a Home Media Server for personalized broadcasting service in ubiquitous environment. A implemented Home Media Server support multimedia contents like audio, video and metadata using wired/wireless digital interface. In bi-directional network environment, the special request of the HMS is sent to TV-Anytime metadata service providers and then the metadata server provides the personalized metadata back to HMS. We describe the actual system configuration and usage example of metadata for contents management.

This paper develops an adaptive, optimal planning algorithm for signal control at a single intersection using an efficient dynamic programming technique. It is called ADPAS (Adaptive Dynamic Programming Algorithm for Signaling). The objective of ADPAS is to minimize the total delay experienced by vehicles passing through an intersection. ADPAS can generate any sequence of green phases to optimize signal control without restriction to fixed cycles of green phases. The algorithm employs as the method to solve the forward DP functional equation, which does not require any prior knowledge of the states of the DP network. The efficiency of the algorithm results from two acceleration techniques that adaptively eliminate inferior states as the algorithm progresses. We verify computational efficiency of ADPAS with several test cases.

In this paper, we consider a class of Inverse Constrained Bottleneck Problems (ICBP). Given two weight vectors and , the constrained bottleneck problem is to find a solution that minimizes -bottleneck weight subject to a budget constraint on -sum weight. Whereas, in the inverse problem (ICBP), a candidate solution is given, we wish to modify the two weight vectors under bound restrictions so that the given solution becomes an optimal one to the constrained bottleneck problem and the deviation of the weights under some norm is minimum. When the modifications of two weight vectors are proportioned, we present a general method to solve the problem (ICBP) under weighted norm and give two examples of the method including the inverse constrained bottleneck spanning tree problem and the inverse constrained bottleneck assignment problem.

In this paper we give a polynomial algorithm for the problem | , =, | ∑ . This result is applied to derive a polynomial algorithm for the problem | , =1| ∑ .

We present differential approximation results (both positive and negative) for optimal satisfiability, optimal constraint satisfaction, and some of the most popular restrictive versions of them. As an important corollary, we exhibit an interesting structural difference between the landscapes of approximability classes in standard and differential paradigms.

We revisit in this paper the probabilistic coloring problem () and focus ourselves on bipartite and split graphs. We first give some general properties dealing with the optimal solution. We then show that the unique 2-coloring achieves approximation ratio 2 in bipartite graphs under any system of vertex-probabilities and propose a polynomial algorithm achieving tight approximation ratio 8/7 under identical vertex-probabilities. Then we deal with restricted cases of bipartite graphs. Main results for these cases are the following. Under non-identical vertex-probabilities is polynomial for stars, for trees with bounded degree and a fixed number of distinct vertex-probabilities, and, consequently, also for paths with a fixed number of distinct vertex-probabilities. Under identical vertex-probabilities, is polynomial for paths, for even and odd cycles and for trees whose leaves are either at even or at odd levels. Next, we deal with split graphs and show that is -hard, even under identical vertex-probabilities. Finally, we study approximation in split graphs and provide a 2-approximation algorithm for the case of distinct probabilities and a polynomial time approximation schema under identical vertex-probabilities.

The majority of previous studies on tolerance allocation have viewed the issue as a design methodology to determine optimal component tolerances on behalf of a manufacturer, while meeting given assembly tolerance requirements. Although a considerable amount of research has been done on this issue, a couple of important questions still remain unanswered. First, how can a design engineer quantitatively incorporate a customer’s perception on a product quality into a tolerance allocation scheme at the early design stage? Second, how can component tolerances and assembly tolerance be optimized in a simultaneous way? To answer these questions, this paper presents the so-called customer-driven concurrent tolerance allocation which is facilitated by the notion of truncated distribution and the use of mathematical programming techniques, while adopting the major principles of Taguchi philosophy. The procedures are demonstrated in a numerical example. The work presented in the paper is an effort to gain insights, which can be useful in practice when setting up guidelines for an overall tolerance allocation.

This paper presents a comprehensive and successful application of data mining methodologies to improve wafer yield in a semiconductor wafer fabrication system. To begin with, this paper applies a clustering method to automatically identify AUF (Area Uniform Failure) phenomenon from data instead of visual inspection that bad chips occurs in a specific area of wafer. Next, sequential pattern analysis and classification methods are applied to find out machines and parameters that are cause of low yield, respectively. Finally, this paper demonstrates an information system, Y2R-PLUS (Yield Rapid Ramp-up, Prediction, analysis & Up Support) that is developed in order to analyze wafer yield in a Korea semiconductor manufacturer.

In this paper, we consider the problem of determining the optimum target values of the process mean and screening limits for a production process under single screening procedure. Two surrogate variables are observed simultaneously in single screening procedure. It is assumed that two surrogate variables are correlated with the quality characteristic of interest. A model is constructed that involve selling price and production, inspection and penalty costs. A method for finding the optimum target values of the process mean and screening limits is presented when the quality characteristic of interest and surrogate variables are assumed to be jointly normally distributed. A numerical example is presented.