• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.4
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• pp.38-46
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• 1999

This paper discusses the repetitive tracking control method for a coarse-fine actuator. The proposed system is composed of a magnetic linear drive as a coarse actuator and a piezoelectric linear positioner as a fine actuator. In particular, nonlinear friction in a magnetic linear drive and hysteresis characteristic of a piezoelectric linear positioner are modeled first. The feedback linearization loop uses these models in tracking position control. The control strategy is then further extended to include a repetitive control algorithm in tracking periodic reference inputs. This repetitive controller is implemented on the existing PID controller augmented with feedback linearization loop. The experimental results show that performance in tracking sinusoidal waveforms is noticeably improved by augmenting a PID controller with feedback linearization loop and a repetitive controller together.

• KDI Journal of Economic Policy
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• v.29 no.2
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• pp.1-40
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• 2007

This paper mainly estimates a trajectory of GDP induced by variations in fiscal expenditure and taxation policy using three variable structural VAR models. By assigning different combinations of identifying restrictions on the disturbances and measuring the corresponding fiscal multipliers, we compare how robust the estimated values of fiscal multipliers are with respect to the restrictions. Then, considering the dependency of Korean economy on the foreign sector, we extend the three variable SVARs to four variable ones by adding a variable reflecting external shocks. Empirical analyses into the Korean quarterly data (from 1979 to 2000) with the three variable SVARs reveal that the size and the significance of the estimated fiscal multipliers in Korea are very small and low or they decay very fast. Results from the four variable SVARs confirm these results while the significance of the effectiveness of fiscal policy is enhanced in some cases.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.102-107
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• 2009

As technology gets developed, medical equipments are also modernized and leading-edge systems, such as PACS become popular. Many scientists noticed importance of medical image processing technology. Technique of region segmentation is the first step of digital medical image processing. Segmentation technique helps doctors to find out abnormal symptoms early, such as tumors, edema, and necrotic tissue, and helps to diagnoses correctly. Segmentation of white matter, gray matter and CSF of a brain image is very crucial part. However, the segmentation is not easy due to ambiguous boundaries and inhomogeneous physical characteristics. The rate of incorrect segmentation is high because of these difficulties. Fuzzy-based segmentation algorithms are robust to even ambiguous boundaries. In this paper a modified Fuzzy-based segmentation algorithm is proposed to handle the noise of MR scanners. A proposed algorithm requires minimal computations of mean and variance of neighbor pixels to adjust a new neighbor list. With the addition of minimal compuation, the modified FCM(mFCM) lowers the rate of incorrect clustering below 30% approximately compared the traditional FCM.

• Journal of KIISE:Software and Applications
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• v.33 no.9
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• pp.741-750
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• 2006

In this paper, we propose a method for reconstructing a 3D object (or a set of objects) from a 2D drawing provided by a designer. The input 2D drawing consists of a set of contours that may partially overlap each other or be self-overlapping. Accordingly, the resulting 3D object(s) may occlude each other or be self-occluding. The proposed method is composed of three major steps: 2D contour analysis, 3D skeleton computation, and 3D object construction. Our main contribution is to compute the 3D skeleton from the self-intersecting 2D counterpart. We formulate the 3D skeleton construction problem as a sequence of optimization problems, to shape the skeleton and place it in the 3D space while satisfying C1-continuity and intersection-free conditions. Our method is mainly for a silhouette-based sketching interface for the design of 3D objects including self-intersecting objects.

• Journal of the Korean Wood Science and Technology
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• v.24 no.2
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• pp.7-14
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• 1996

이 연구(硏究)는 미국(美國) 남부(南部)의 9개 주(州)에 소재하고 있는 가구공장(家具工場)에 대한 설문조사(設問調査)를 통해 산업구조(産業構造)와 마케팅 전략을 조사(調査) 하였다. 이번 조사 결과를 요약하면 1. 가구공장(家具工場)이 사용하는 원자재(原資材)는 red oak, pine, poplar, maple 등으로 한국 가구공장(家具工場)이 원자재(原資材)의 95% 이상(以上)을 남양재(南洋材)에 의존하고 있는 것과 뚜렷한 차이를 보였다. 2. 가구공장(家具工場)의 68.8%는 주요시장(主要市場)을 자기 주내(州內)에 가지고 있고, 28.8%가 주(州) 밖에 그리고 조사공장(祖師工場)의 2.5%만이 수출(輸出)했다. 아울러 수출(輸出)이나 자기 주외(州外)에 시장(市場)을 가지고 있을 수록 공장규모(工場規模)가 컸다. 3. 주요시장(主要市場)까지의 거리는 50%가 160km 이내(以內)였는데 이것은 활엽수 제재목(製材木) 공장(工場)의 30%가 800km 밖에까지 시장(市場)을 가지고 있는 것에 비해 매우 좁은 시장(市場)을 형성하고 있는 것으로 나타났다. 4. 제품(製品)의 유통(流通)은 직접 소비자(消費者)에게 출하(出荷)하는 것이 3/4로 압도적이었지만, 중간유통기관에 출하(出荷)하는 곳일수록 공장규모(工場規模)도 컸다. 5. 가구산업(家具産業)의 성공에 기여(寄與)하는 요인(要因)으로는 제품품질(製品品質)과 장기적(長期的)인 소비자(消費者)와의 관계(關係) 증진(增進)을 가장 중요한 요인으로 지적하였고, 그 다음으로 기업에 대한 평판(評判)과 높은 소비자(消費者) 서비스를 지적하였다. 반면에 가구산업발전(家具産業發展)의 장애요인(障碍要因)으로는 원자재(原資材)의 품질(品質)과 원료(原料)의 불안정(不安定)한 공급(供給)이 제일 중요하게 인식되어 있었다. 그러나 해외공급자(海外供給者)와의 경쟁(競爭)은 장애요인(障碍要因)으로 거의 인식되고 있지 않았다. 6. 공장(工場)의 확장(擴張)이나 이전(移轉)에 가장 큰 영향을 미치는 요인(要因)으로는 노동력(勞動力) 문제(問題)(생산성(生産性)과 비용(費用))가 가장 중요하게 지적되었고, 그 다음으로 세금구조(稅金構造), 건설비(建設費) 등이 지적되었다.

• Journal of Engineering Education Research
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• v.8 no.1
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• pp.20-30
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• 2005

Recently, a new education paradigm 'Self-directed Learning' has attracted considerable attention. Problem-Based Learning (PBL) has been recognized as methodology to help students expand scientific thinking and knowledge. improve applicability, develope critical knowledge, and creatively solve problems. There have been significant efforts to develope PBL-based courses in mechanical engineering. A new PBL-based, multi-disciplinary course 'Product Dissection and Design Reasoning' has been developed in this paper. The course examines the way in which products and machines work and is intended to show freshman or sophomore level students how fundamental physical principles relate to engineering practice through hands-on dissection experience : thus, the course emphasizes the importance of knowledge of the fundamental physics for design reasoning. The primary role of this course is to develop creative design manpower. This paper describes the philosophy and content of this course and presents results from one year of development.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.549-552
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• 2013

The research conducted here focuses on the definition and organization of information privacy concerns in e-commerce process. Based on the identified concept of information privacy concerns(IPC), this study additionally explores the interrelationships among consumers' individual characteristics(self-efficacy, digital literacy, customer alienation), customer satisfaction and intention to buy. Through empirical model analysis, this study found that self-efficacy and digital literacy affect negatively IPC, while customer alienation has an positive effect on IPC. IPC affects positively customer satisfaction. Academically, this study extends IPC to an empirical research model by identifying the conceptualization and organization of IPC. Moreover, practically, e-commerce providers can develop how to relieve IPC of online consumers.

• Journal of Korean Society of Disaster and Security
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• v.13 no.3
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• pp.59-74
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• 2020

The purpose of this study is to explore the subjective perception of college students' Internet addiction by applying photovoice method, a participatory research method. The subjects of the study were nine university students at G University. The data were analyzed by orientation, photo collection, photo selection, contextualizing and codifying according to the general photo voice research procedure.As a result, 15 sub-categories were derived based on the meaning of Internet addiction, the effects of Internet addiction on life, and how to get out of Internet addiction. The perception of the meaning of Internet addiction was divided into five categories: 'loss of self-regulation', 'habit without exit', 'disconnection from the world', 'loss of me', and 'voluntary prison'. The effects of Internet addiction on life were 5 categories: 'health deterioration', 'social isolation', 'broken daily life', 'anonymous violence' and 'my discovery and life extension'. In terms of how to get out of internet addiction, 'self-looking', 'new hobbies', 'nearby', 'reality meetings', and 'forced blocking' were derived. It suggested the discussion about Internet addiction viewed by college students and the implications of constructing a counseling program that can help to use the Internet correctly.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.2 s.302
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• pp.1-10
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• 2005

This paper presents a technique for localization of a mobile robot using a single ultrasonic sensor. The mobile robot is designed for operating in a well-structured environment that can be represented by planes, edges, corners and cylinders in the view of structural features. In the case of ultrasonic sensors, these features have the range information in the form of the arc of a circle that is generally named as RCD (Region of Constant Depth). Localization is the continual provision of a knowledge of position which is deduced from it's a priori position estimation. The environment of a robot is modeled into a two dimensional grid map. we defines a physically-based sonar sensor model and employs an extended Kalman filter to estimate position of the robot. The performance and simplicity of the approach is demonstrated with the results produced by sets of experiments using a mobile robot.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.43-54
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• 2016

The purpose of this research was to develop a group counseling program for improving the psychological well being and mental health of the university entrants, and to verify the effectiveness of the program. The research procedure consisted of the program development step and the program verification step, and in detail, 6 steps of program development processes were established. The subjects of the research were 116 university entrants, and 15 group counselings were conducted. As the result, significant variations were shown in the scores of the psychological well being and mental health through the pre and post test on the group, and the experience report analysis evaluated that the objective of the program was accomplished. It is expected that these results would be helpful for suggesting various education methodology or education policy for the university entrants.