• Journal of the Korean Institute of Telematics and Electronics C
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• 제34C권6호
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• pp.79-88
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• 1997

New technologies, systems, and services in telecommunication have increased the need for an efficient and robust control mechanism to protect switching systems from overload. To achieve proper control, it is necessary to find a set of parameters that can describe the system. However, it is difficult to find types of data that can form a suitable basis for control. In this paper, we categorize the load status of a switching system into three classes (i.e., normal state, pre-overload state, and overload state) and formulate the overload detection as a classification problem. We find the relationships between the load classes and a set of monitored switching system parameters by applying a fuzzy rule-generation method. The rules are automatically generated from training data. Simulation results involving a switching system is given.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.457-458
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• 2007

This paper propose a method for representing distributed data of sensor networks. The proposed method is based on a general distributed regression framework that models sensor data by fitting a global function to each of the local measurements and explores the possible extensions of distribution regression by using complex signal representations. In order to reduce the amount of processed data and the required communication, the signal model has to be as compact as possible, with the ability to restore the arbitrary measurements. To achieve this requirement, data compression step is included, where the basis function set is changed to an overcomplete set. This have better advantages in case of nonstationary signal modeling than complete base representation.

• Proceedings of the KIPE Conference
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.268-269
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• 2017

This paper presents an improved current control strategy for a three-phase grid-connected inverter under distorted grid conditions. Distorted grid condition is undesirable due to negative effects such as power losses and heating problem in electrical equipments. To enhance the power quality of distributed generation systems under such a condition, a modulated finite control set - model predictive control (MFCS-MPC) scheme will be proposed, in which the optimal switching signals of inverter are chosen by online basis using the principle of current error minimization. In addition, the moving average filter (MAF) is used to improve the phase-lock loop in order to obtain the harmonic-free reference currents on the stationary frame. The usefulness of the proposed MFCS-MPC method is proved by the comparative simulation results under different operating conditions.

• The Mathematical Education
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• 제49권4호
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• pp.395-410
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• 2010

Current mathematics of CSAT(College Scholastic Ability Test) faces time to prepare examination questions according to the new curriculum making this year the last. MEST(Minister of Education, Science and Technology) already decided the range of examination in 2008. However, the discuss about how to construct the questions and what form of questions should be set was not conducted enough. Mathematics items of CSAT will have to undergo changes both in 2012 and 2014. Also, reconstruction of the examination questions for the past 16 years and the exploration of the new direction are strongly required. To accord with these requirements, this study analyze Japan's college entrance exam, NCTUA(National Center Test for University Admissions) which is the most similar to our exams. And then on the basis of this, the applicable implication to set mathematics questions in 2012 and 2014 CSAT will be deducted.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제14권23호
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• pp.57-64
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• 1991

The preliminary, advanced and final evaluation of R&D project is essential in order to reduce loss of resource and opportunity and to minimize uncertainty resulting from optimal selection and efficient progress of R&D project. This thesis examined characteristics of deterministic evaluation, economical evaluation, and OR-approach evaluation as theoretical methodology of evaluation of R&D project applicable to food industry in Korea by using scoring method, one of deterministic evaluations. In addition, this thesis divided the evaluation factors for preliminary evaluation of R&D project into 5 groups and 30 factors on basis of the environment of domestic companies and set up the standard of each evaluation factors and contains marking-selecting way. But, generally, the evaluation model by this thesis, as the conditions of the business company environment are different to each other, contents to be set up evaluation factors, evaluation standard and decision method conforming to each the environment of the business companies with referring to as one standard of evaluation project for selecting R&D project.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제42권2호
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• pp.28-35
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• 2019

Since guided missiles with the characteristics of the one-shot system remain stored throughout their entire life cycle, it is important to maintain their storage reliability until the launch. As part of maintaining storage reliability, period of preventive test is set up to perform preventive periodic test, in this case failure detection rate has a great effect on setting up period of preventive test to maintain storage reliability. The proposed method utilizes failure rate predicted by the software on the basis of MIL-HDBK-217F and failure mode analyzed through FMEA (Failure Mode and Effect Analysis) using data generated from the actual field. The failure detection rate of using the proposed method is applied to set periodic test of the actual guided missile. The proposed method in this paper has advantages in accuracy and objectivity because it utilizes a large amount of data generated in the actual field.

• East Asian mathematical journal
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• 제25권3호
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• pp.229-245
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• 2009

G. Cantor gave a deep influence to the society of mathematics in many ways, especially in the set theory. It is important for gifted and talented high school students in mathematics to understand the Euler constant and the fractal dimension of the Cantor set in a heuristic sense. On the historic basis of mathematics and the standard of high school students, we give the teaching method for the talented high school student to understand them better. Further we introduce the Riesz-N$\acute{a}$gy-Tak$\acute{a}$cs distribution and its first moment. We hope that from these topics, the gifted and talented students in mathematics will have insight in the analysis of mathematics.

• Korean Institute of Interior Design Journal
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• 제25권1호
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• pp.35-46
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• 2016

The purpose of this study was to identify the characteristics of expressionism in the space of deconstructive architecture by comparing the spaces of "The Cabinet of Dr. Caligari" video with the expressionist characteristics of film narrative structure and expressionist architecture and making an expansion based on the results. The findings were as follows: first, the "The Cabinet of Dr. Caligari" is divided into two set spaces: one has the perspective representation distorted in the viewpoint of a mad person applied to it, and the other reflects the viewpoint of a normal person from medieval paintings with no perspective. Second, the expressionist buildings did not reflect the expressionist characteristics in the interior spaces as fully as in the exterior ones. Third, the incomplete combination of Signifiant and $Signifi{\acute{e}}$, which were the theoretical basis of deconstructive architecture, showed a tendency of binary opposition like the double narrative structure of "The Cabinet of Dr. Caligari." Fourth, deconstructive architecture seems to embody the exterior form and interior space of "The Cabinet of Dr. Caligari" and its set spaces in the phenomenal aspect but exhibits its limitations with the realization of dynamics, one of the characteristics of expressionism. Finally, the Seattle Public Library presents the best embodiment of expressionist characteristics found in the set spaces of "The Cabinet of Dr. Caligari" while seeking after the combination of horizontal and vertical paths of action through the spiral ramps and inclined slabs.

• Journal of Mechanical Science and Technology
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• 제18권6호
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• pp.972-978
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• 2004

Forward slip is an important parameter often used in rolling-speed control models for tandem hot strip rolling mills. In a hot strip mill, on-line measurement of strip speed is inherently very difficult. Therefore, for the set-up of the finishing mill, a forward slip model is used to calculate the strip speed from roll circumferential velocity at each mill stand. Due to its complexity, most previous researches have used semi-empirical methods in determining values for the forward slip. Although these investigations may be useful in process design and control, they do not have a theoretical basis. In the present study, a better forward slip model has been developed, which provides for a better set-up and more precise control of the mill. Factors such as neutral point, friction coefficient, width spread, shape of deformation zone in the roll bite are incorporated into the model. Implementation of the new forward slip model for the control of a 7-stand hot strip tandem rolling mill shows significant improvement in roll speed set-up accuracy.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 한국퍼지및지능시스템학회 2006년도 추계학술대회 학술발표 논문집 제16권 제2호
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• pp.29-32
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• 2006

In this paper, we propose a customer personalized system that presents the web pages to users which are customized to their individuality. It analyzes the action of users who visit the shopping mall, and preferentially supplies the necessary information to them. When they actually buy some items, it forecasts the users' access pattern to web site and their following purchasable items and improves their web pare on the bases of their individuality. It reasons the relation among the web documents and among the items by using the log data of web server and the purchase information of DB. For reasoning it employs Rough Set, which is a method that searches the association rule and offers most suitable cases by reduces cases. It reasons the web pages by considering the users' access pattern and time by using the web log and reasons the users' purchase pattern by using the purchase information of DB. On the basis of the relation among them, it appends the related web pages to link of users' web pages and displays the inferred goods on users' web pages.