• The Journal of the Acoustical Society of Korea
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• v.21 no.4
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• pp.178-178
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• 2002

In this paper, we propose an adaptive wavelet method for car interior noise cancellation. For this purpose, we use a node dependent threshold which minimizes the Bayesian risk. We propose a noise estimation method based on spectral entropy using histogram of intensity and a candidate best basis instead of Donoho's best bases. And we modify the hard threshold function. Experimental results show that the proposed algorithm is more efficient, especially to heavy noisy signal than conventional one.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.3
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• pp.197-203
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• 2009

Finite field arithmetic is very important in the area of cryptographic applications and coding theory, and it is efficient to use normal bases in hardware implementation. Using the fact that $GF(2^{mk})$ having a type-I optimal normal basis becomes the extension field of $GF(2^m)$, we, in this paper, propose a new serial multiplier which reduce the critical XOR path delay of the best known Reyhani-Masoleh and Hasan's serial multiplier by 25% and the number of XOR gates of Kwon et al.'s multiplier by 2 based on the Reyhani-Masoleh and Hasan's serial multiplier for type-I optimal normal basis.

• Korean Management Science Review
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• v.22 no.1
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• pp.103-125
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• 2005

Korean government is planning to adopt double entry bookkeeping with accrual basis in the government accounting system. This paper attempts to identify influencing attitudes of information producers toward the acceptance of the new service system. Several models are introduced, including Luder's Contingency Model, Cheng's Politico-Economic Model of Accounting Policy Choice, Roger's Diffusion of innovation, and Davis's Technology Acceptance Model(TAM). A set of constructs are developed as fellows : information producers' knowledges, experiences, altitudes toward the reform, characteristics of cash based accounting system and new accrual based system, a chief executive officer's willingness to support, availability of supporting systems, and social Influences from external environment. This study also incudes hey factors used in TAM, such as perceived usefulness and ease of use. Survey responses are gathered from accounting officers in government ministries and agencies as well as from local governments. Regression analysis shows that, for information producers, both 'perceived ease of use' and 'perceived usefulness' of the new system are the best explanatory variable for the dependent variable. It has also found that 'perceived usefulness' is explained best by individual characteristics such as knowledge and experiences, quality of current cash based s1n91e entry bookkeeping system, chief executive's support, Positive supporting systems and social influences. The useful guidelines for implementing double-entry bookkeeping system with accrual basis are also provided.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.6
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• pp.19-19
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• 2002

In this paper the authors explore the effect of bandwidth sharing to the utility of the customer for the best-effort Internet services and draw a basis for the pricing principle in Internet Protocol networks. Especially, we investigate the behavior of a customer′s utility in case an arbitrary amount of additional bandwidth is allowed to each customer for the elastic traffic, which is the typical example of the non-real time Internet data traffic. After drawing the utility curve, which will be proved to follow the concave curve, we will apply it to the pricing of Internet traffic. Finally, via numerical experiments, we will illustrate the validity and implication of the proposed method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.6
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• pp.277-284
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• 2002

In this paper the authors explore the effect of bandwidth sharing to the utility of the customer for the best-effort Internet services and draw a basis for the pricing principle in Internet Protocol networks. Especially, we investigate the behavior of a customer's utility in case an arbitrary amount of additional bandwidth is allowed to each customer for the elastic traffic, which is the typical example of the non-real time Internet data traffic. After drawing the utility curve, which will be proved to follow the concave curve, we will apply it to the pricing of Internet traffic. Finally, via numerical experiments, we will illustrate the validity and implication of the proposed method.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.6
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• pp.68-73
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• 2005

Tire manufactures have dealt with noise problem by varying the pitch of the tread. The various formulas for the variations are generally determined differently, however. Often these variations are based on a combination of trial and error, intuition, and economics. Some manufactures have models and analogs to test tread patterns and their variations. These efforts, however practical, do not determine the best variation beforehand or guarantee the best results. For this reason it was felt that a general mathematical approach fur determining the best variation was needed. Moreover, the method should be completely general, easy to use, and sufficiently accurate. This paper discusses a mathematical method called Mechanical Frequency Modulation(MFM) which meets the above requirements. Thus, MFM pertains to computing an irregular time sequence of events so that the resulting excitation spectrum is shaped to a preferred form. The first part of this paper treats the theoretical basis for computing an optimum variation ; the second part discusses experimental results and simulation program which corroborate the theory.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.2
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• pp.137-143
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• 2005

Autonomous mobile robot has an ability to navigate using both map in known environment and sensors for detecting obstacles in unknown environment. In general, autonomous mobile robot navigates by global path planning on the basis of already made map and local path planning on the basis of various kinds of sensors to avoid abrupt obstacles. This paper provides a global path planning method using self-organizing feature map which is a method among a number of neural network. The self-organizing feature map uses a randomized small valued initial weight vectors, selects the neuron whose weight vector best matches input as the winning neuron, and trains the weight vectors such that neurons within the activity bubble are move toward the input vector. On the other hand, the modified method in this research uses a predetermined initial weight vectors, gives the systematic input vector whose position best matches obstacles, and trains the weight vectors such that neurons within the activity bubble are move toward the input vector. According to simulation results one can conclude that the modified neural network is useful tool for the global path planning problem of a mobile robot.

• Journal of KIISE:Software and Applications
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• v.37 no.6
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• pp.455-463
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• 2010

In this paper, we present an approach to sentence boundary detection for web documents that builds on statistical-based methods and uses rule-based correction. The proposed system uses the classification model learned offline using a training set of human-labeled web documents. The web documents have many word-spacing errors and frequently no punctuation mark that indicates the end of sentence boundary. As sentence boundary candidates, the proposed method considers every Ending Eomis as well as punctuation marks. We optimize engine performance by selecting the best feature, the best training data, and the best classification algorithm. For evaluation, we made two test sets; Set1 consisting of articles and blog documents and Set2 of web community documents. We use F-measure to compare results on a large variety of tasks, Detecting only periods as sentence boundary, our basis engine showed 96.5% in Set1 and 56.7% in Set2. We improved our basis engine by adapting features and the boundary search algorithm. For the final evaluation, we compared our adaptation engine with our basis engine in Set2. As a result, the adaptation engine obtained improvements over the basis engine by 39.6%. We proved the effectiveness of the proposed method in sentence boundary detection.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.211-216
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• 2009

Bidding systems in the domestic public construction work have been amended many times since the lowest-bidding system was implemented in 1951. However, this hasn't had much success. Competition in technical development among companies has declined as the contracts for buildings are given to company which submits the lowest price without considering traits of projects. In addition, as the construction market turns to the limitless competition system due to FTA(Free Trade Agreement), advanced techniques are needed to promote the national competitive power. Considering the needs of the times, Korean government announced that "Best Value Contract (Design-Bid-Build)" and "Bridging Contracts (Design-Build)" are included to 4 existing bidding systems in October 2007. Thus this study aims to suggest devised the evaluation criteria including major items for evaluating bidders, in order to establish and revitalize the best-value bid system successfully.

• Nuclear Engineering and Technology
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• v.52 no.4
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• pp.742-754
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• 2020

Zircaloy cladding oxidation is an important phenomenon for both design basis accident and severe accidents, because it results in cladding embrittlement and rapid fuel temperature escalation. For this reason during the last decade, many experts have been conducting experiments to identify the oxidation phenomena that occur under design basis accidents and to develop mathematical analysis models. However, since the study of design extension conditions (DEC) is relatively insufficient, it is essential to develop and validate a physical and mathematical model simulating the oxidation of the cladding material at high temperatures. In this study, the QUENCH-05 and -06 experiments were utilized to develop the best-fitted oxidation model and to validate the SPACE code modified with it under the design extension condition. It is found out that the cladding temperature and oxidation thickness predicted by the Cathcart-Pawel oxidation model at low temperature (T < 1853 K) and Urbanic-Heidrick at high temperature (T > 1853 K) were in excellent agreement with the data of the QUENCH experiments. For 'LOCA without SI' (Safety Injection) accidents, which should be considered in design extension conditions, it has been performed the evaluation of the operator action time to prevent core melting for the APR1400 plant using the modified SPACE. For the 'LBLOCA without SI' and 'SBLOCA without SI' accidents, it has been performed that sensitivity analysis for the operator action time in terms of the number of SIT (Safety Injection Tank), the recovery number of the SIP (Safety Injection Pump), and the break sizes for the SBLOCA. Also, with the extended acceptance criteria, it has been evaluated the available operator action time margin and the power margin. It is confirmed that the power can be enabled to uprate about 12% through best-estimate calculations.