• Journal of Advanced Marine Engineering and Technology
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• v.36 no.5
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• pp.694-699
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• 2012

This paper proposes a new sensorless speed control scheme of permanent magnet DC motor using a numerical model and hysteresis controller, which requires neither shaft encoder, speed estimator nor PI controllers. By supplying the identical instantaneous voltage to both model and motor in the direction of reducing torque difference, the rotor speed approaches to the model speed, namely setting value and the system can control motor speed precisely. As the numerical model whose electric parameters are the same as those of the actual motor is adopted, the armature rotating speed can be converged to the setting value by controlling torque on both sides to be equalized. And the hysteresis controller controls torque by restricting the torque errors within respective hysteresis bands, and motor torque are controlled by the armature voltage. The experiment results indicate good speed and load responses from the low speed range to the high, show accurate speed changing performance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.2
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• pp.107-114
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• 2014

This paper proposes a common rail pressure control algorithm for passenger car diesel engines. For handling the parameter-varying characteristics of common rail systems, the quantitative feedback theory (QFT) is applied to the design of a robust rail pressure control algorithm. The driving current of the pressure control valve and the common rail pressure are used as the input/output variables for the common rail system model. The model parameter uncertainty ranges are identified through experiments. Rail pressure controller requirements in terms of tracking performance, robust stability, and disturbance rejection are defined on a Nichols chart, and these requirements are fulfilled by designing a compensator and a prefilter in the QFT framework. The proposed common rail pressure control algorithm is validated through engine experiments. The experimental results show that the proposed rail pressure controller has a good degree of consistency under various operating conditions, and it successfully satisfies the requirements for reference tracking and disturbance rejection.

• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.709-716
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• 2007

An active steering bogie has been theoretically proved to improve both stability and steering performance remarkably. However, It has not been commercialized yet even though many researchers have been trying to develop it because some technical difficulties still exist such as information acquisition fer active control, increasing mechanical components, high energy consumption, fail-safe problem and so on. To solve those problems, an advanced active steering mechanism is proposed in this paper. With this mechanism, required control force is small enough to use direct drives. Therefore, the number of additional mechanical components can be minimized since mechanical transducers like gears are not necessary. Fail-safe function can be also inserted easily. In this paper, concept design of the proposed active steering bogie is introduced and the possibility is verified through computer simulation using linear dynamic model.

• Journal of Convergence for Information Technology
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• v.8 no.5
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• pp.251-261
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• 2018

Under the great influence of ICT technology, China is forging ahead steadily and rapidly in the area of smart farming. In the last decade, Chinese government has carried out strategic plans to promote its economic development in agriculture, such as the plan of Made In China 2025 and One Belt One Road initiative. This thesis's objective is to analyze how such plans and initiative can provide 'windows of opportunity' to the development of smart farming industry in China. China led the development of smart agriculture by making a T-shaped rise which is composed with 'One Belt One Road Initiative and Made in China 2025 Plan. This thesis is divided into three types as path-following catch-up, path-skipping catch-up, path-creating catch-upAs this thesis also manages to provide some implications on the export strategies of South Korea's smart farming industry by understanding chinese samrt farm industry.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.9
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• pp.723-732
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• 2001

In this paper, the neurofuzzy controller of optically guided AGV is proposed to improve the path-tracking performance A differential steered AGV has front-side and rear-side optical sensors, which can identify the guiding path. Due to the discontinuity of measured data in optical sensors, optically guided AGVs break away easily from the guiding path and path-tracking performance is being degraded. Whenever the On/Off signals in the optical sensors are generated discontinuously, the motion errors can be measured and updated. After sensing, the variation of motion errors can be estimated continuously by the dead reckoning method according to left/right wheel angular velocity. We define the estimated contour error as the sum of the measured contour in the sensing error and the estimated variation of contour error after sensing. The neurofuzzy system consists of incorporating fuzzy controller and neural network. The center and width of fuzzy membership functions are adaptively adjusted by back-propagation learning to minimize th estimated contour error. The proposed control system can be compared with the traditional fuzzy control and decision system in their network structure and learning ability. The proposed control strategy is experience through simulated model to check the performance.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.58-58
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• 2016

This study aims to enhance Korea's competitiveness by taking the lead in the international standardization and relevant global market. This is to be achieved by performing the role of First Mover through the resolute investment from Fast Follower that is servile to the decision of the organization in the e-Navigation strategy that has been promoted by the IMO. The study methodology is an integrated approach. It is established by modelling LSCM G2B2C2 Platform in maritime safety/security logistics and applied to the enhancement of maritime safety/security in global LSCM. This paper externally contributes to the reduction of world maritime accidents and exalt the national prestige; internally, the enhancement of the national competitiveness through the improvement of shipping port logistics and others. These eventually contribute to Korea's economic development that is combined by both theory and practice and of practical use of the integrated approach.

• Journal of The Korean Association For Science Education
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• v.26 no.7
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• pp.856-869
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• 2006

J. J. Schwab is usually considered as the founder of the concept of scientific enquiry, perhaps the most important key word of science education of the 20th century. Mainly through the method of literature review, this study reappraises Schwab's life as a science educator as well as a curriculum scholar, and his ideas concerning several important issues about science and science education. Like other eminent science educators, before the 1950s, who were originally talented scientists but later became engaged in educational activities, Schwab were trained and known as a genetic scientist, but later he concentrated on university reform, curriculum studies and science education. His academic interest was very diverse across different disciplines, from biology and science in general to history, philosophy and education. The essence of his theory of scientific enquiry was 'to teach science as science', and the best way to do it was 'to teach science as enquiry'. With enquiry, however, he tried to deliver some important but differentiated meanings, for example by distinguishing 'science as enquiry' and 'teaching as enquiry', and 'static enquiry' and 'fluid enquiry'. Scientific enquiry was the core concept upon which many of his ideas concerning science education and education in general were based, such as the diversity of science, textbooks, curriculum and roles of teachers. In summary, Schwab can be characterized as a rational reformist of science education, who tried to identify the very nature and goals of the discipline and to bring its substantial changes with concrete and practical guidelines. Nevertheless, some of his ideas, like the diversity of science and conceptual invention, have been handed down by his followers frequently with considerable distortion.

• Journal of Distribution Science
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• v.9 no.1
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• pp.29-38
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• 2011

Since a distribution market was opened in 1993 after the conclusion of the Uruguay Round (UR), various new businesses emerged in the Korean retail industry, such as convenience shops, supermarkets, specialty stores, non-store marketing methods, and cyber shopping malls, in addition to traditional markets and department stores. Competition among these retail businesses has intensified. According to the National Statistical Office (NSO), the growth rate of the total retail industry has shown a 32% increase in the past 5 years. While department stores, supermarkets, specialty stores, and other non-store retailing venues have shown signs of stagnation at a growth rate of 20-30%, which is similar to the growth rate of the entire retail industry, convenience shops and non-store marketing have shown 60-70% growth over the same period. By comparison, the growth rate of cyber shopping malls has nearly tripled. When applying development aspects of retail businesses through the competition to the retail life cycle, mom-and-pop stores and traditional markets have already entered the decline phase as specialty stores reach their maturity phase and demonstrate their limit of growth. Department stores are now in the latter part of the growth phase, which is still considered to have some growth potential. Big super markets are still in the early part of their growth stage although they were introduced 20 years ago. Meanwhile, retail businesses such as convenience stores, supermarkets, mail order houses, and warehouse stores are entering the middle growth phase and are expected to continue with their quantitative growth. At a time when most retail businesses in Korea are in a state of development or in the full growth stage, what kind of new innovative retailing will appear and develop? Moreover, what growth engine will drive it? This study analyzes the appearance of innovative retailing and its development process by establishing a discussable consumer's choice model through the interlocking mutual behavior of differentiated competitiveness and consumers' choice based on an awareness of this issue. The analysis of the results of this study can be summarized as follows. First, if a new vacuum zone emerges at the retail market level, innovative retailing such as low price/low service or high price/high service will emerge simultaneously. Second, if the number of new businesses in the vacuum zone increases, this will create competitiveness among the businesses, and each retailer will develop raising of level. Third, if a new business that raises the level develops, competition between the new and the existing retailer will occur, and an assimilation process between the existing retailing and the new retailing will be unfolded. Fourth, each retailing will promote distribution innovations in order to break the frontier of the existing distribution technology, and other retailing will follow the innovator. On the basis of an analysis of the abovementioned results, this study presents the following three suggestions. First, responding to the consumer's decision-making process on the attributes of retail shops that promote differentiation in strategies, this study established a consumer's choice model that can be discussed in relation to changes in market share. Second, this study provided an analysis of the emerging and developmental processes of innovative retail businesses using a more precise logical structure on the basis of the consumer's choice model described in this study. Third, the development process of retail businesses discussed in this study presented retailing solutions regarding management aspects on how to compose a strong retail mix that can help retail businesses gain competitive advantages in the market.

• Journal of architectural history
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• v.10 no.4 s.28
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• pp.77-92
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• 2001

현대의 건축시기는 다원성의 시기 또는 복합성의 시기라고 불리운다. 모더니즘과 포스트모더니즘의 시기를 거치며 다양한 형태적 실험의 과정을 겪었고 수많은 이데올로기와 이론들로 무장된 논쟁의 역사도 갖게 되었다. 이러한 현대건축의 다양성은 건축디자인이라는 전문직의 사회에 기여하는 역할을 반추(反芻)함과 동시에 다변하는 인간사고의 역동성을 반영하고 있다. 건축관련 책자나 저널 등에서 흔히 발견할 수 있는 Neo-Classicism, Deconstructivism, Minimalism, High-Tech, New Moderns 등등의 건축양식들은 스타일을 지칭하는 언어라기보다는 건축적 사고를 지칭하는 언어라고 할 수 있다. 결국 건축디자인이라는 작업은 인간을 둘러 싼 건조환경의 생성에서 출발하는 것이므로 건축적 사고방식은 그 시기의 사회현상과 밀접한 관계를 맺게 된다. 20세기 말부터 불어닥친 디지털 문화의 사회변혁은 전 세계를 하나의 채널로 엮게 되었고, 이러한 영향들은 지역과 민족, 그리고 종교적인 요소들까지도 혼합하여 국경을 초월한 미래의 새로운 이상들을 꿈꾸게 되었다. 19세기 산업혁명과 함께 급속히 벨라진 인류문명의 진보는 필수적으로 세계화를 동반하는 것이고, 세계화와 지역성사이의 괴리를 통해 나타나는 문화적 비판과 충돌은 아직도 진행상태인 것이다. 세계화라는 통염은 문명의 보편성을 기반으로 하며 전통문화의 파괴가 뒤따를 수밖에 없는데, 현재와 같이 IT혁명을 통해 급속도로 빨라진 세계문화의 교류는 한 국가가 뿌리를 내리고 있는 문화적 유산이라는 토양을 포기하여야 할 단계에 와 있다고 논평할 정도이다. 여기서 건축은 문화적 상징으로 작용하게 되는데, 그것이 심미적이든 관습적이든 또는, 경제적이든 건축가는 해답의 제시라는 임무에 직면하게 된다. 20세기에 진행된 모더니즘의 건축은 구조와 공간에 대한 고전건축의 숙원을 고덕건축이 이룬 것처럼 15세기 르네상스 시대로부터 진행된 형태와 공간, 기능, 그리고 아름다움과 기술(technology) 또는 경제성 등에 대한 건축적 의문과 탐구를 일단락지었다고 할 수 있다. 이러한 모더니즘의 한복판에 Mies van der Rohe라는 거장이 깊은 발자국을 남기며 한 시대를 이루었고 그가 남긴 시대정신의 이념과 가치를 Miesianism이라고 부른다. 실용성과 도덕성을 근본으로 하는 Miesianism은 대중에 호소하는 미적 표현주의를 부정하고 지역정서를 중시하는 문맥적 접근방식을 경시함으로써 보편화라는 현상을 불러일으킨 국제주의 양식의 한 부류로 비판을 받아왔다. 즉, Miesianism의 단순하고 강렬한 외형적 요소는 그것이 내포하는 기술적 합리성이나 공간적 완결성을 무시한 채 전 세계에 영향을 미쳤고 동시에 지역적 저항을 받게 되었다. 시카고 및 전 세계의 Miesian들, 즉 Mies van der Rohe의 제자들이나 그로부터 영향을 받은 수많은 건축가들은 이러한 저항과 비판에 직면하게 되며 새로운 사고의 시대적 요구 앞에 고뇌하게 된다. 한국에서는 1978년 Mies van der Rohe의 제자인 김종성이 미국에서 서울로 돌아와 '서울건축컨설탄트'를 설립하며 본격적으로 Miesianism의 규범적 건축론을 설파하기 시작하였다. 이른바 시카고 국제주의학파의 건축전수라고 할 수 있는데 '서울건축컨설탄트'를 통하여 배출된 김종성의 제자들은 명쾌하고도 간결한 건축해법의 경험을 토대름대로의 정체성을 갖고자 노력하였으나 결국 다원적 가치를 요구하는 시대적 흐름 속에 혼란을 겪고 있는 것 또한 사실이다. 본 연구는 Miesianism의 기원을 밝히고 그것의 실수와 오류를 밝힘과 동시에 현대의 여러 가지 건축유형들과 비교하여 봄으로써 Post-Miesianism의 실체와 그 미래에 대하여 고찰하여 보고자 한다. 미스의 유산이라고 할 수 있는 Miesianism의 요체는 첫째, Schinkel로부터 이어받은 시대정신의 사명감, 둘째, Berlage가 전해준 전문가로서의 도덕성을 바탕으로 하여 이루어진 기술적 합리성의 실현, 그리고 마지막으로 그 당시의 추상예술에 대한 이해로써 받아들인 nee-Suprematism의 아방 가르데적인 자세라고 할 수 있다. 그러나 이것들을 전파하고 수용하는 과정에서 미스적인 단순하고 명쾌한 외관이 더욱 강한 인상을 남기게 되었고 또한 미스가 현대성의 본질이라고 믿는 기술의 전수는 모든 외관을 동일하게 만드는 International Style로서의 보편적 획일성을 초래하였다. Mies van der Rohe의 강력하고 규범적인 dogma는 그의 제자들에게는 강렬한 카리스마로 각인되었고, Mies가 원한 것이 아닐지라도 그들을 하나의 틀 속에 가두는 영향력을 행사하였다. 2세대이든 3세대이든 기술적 합리성과 추상적 단순미라는 믿음을 맹목적으로 추종할 때 그들은 Miesian으로 남아있게 되며, 거기서 벗어났을 때 non-Miesian, 또는 배신자로 취급하기까지 하였다. 이것은 미스의 제자들에게 강한 족쇄가 되어 형태적 또는 개념적 변화의 시도를 어렵게 하였고 시대적 요구에 부응하지 못한다는 평가에 이르게 되었다. 문화의 다양성과 역동성을 인정함과 동시에 Miesianism에 대한 새롭고 시대에 적합한 해석을 기대하게 되는데, 이러한 기대 속에서 우리는 Post-Miesianism이라는 새로운 유형을 엿볼 수 있게 된다. Post-Miesianism의 징후를 현대의 다양한 건축유형에서 발견할 수 있는데, High-Tech의 구축적이고 정밀한 건축 기술적 해법과 Minimalism의 반복성을 통한 추상미의 표현 등에서 뿐만이 아니라 Post-Modernism의 인간성의 추구나 문맥적 고려, 또는 해체주의의 형이상학적이고 아방가르데적인 실험주의 정신까지조차 Post-Miesianism이 공유할 수 있는 부분이 있다고 보여진다. 또한, 미스의 영향이 2세대, 3세대의 건축가들에게 미치면서 여러 방향으로 변질되어 가는 것을 우리는 발견할 수 있으며 그러한 시대성에 적응하는 시도들이야말로 새로운 미래를 향한 Post-Miesianism의 실체인 것이다. Mies가 말하였듯이 한 시대의 끝은 그 시대가 완전히 이해되었을 때이며, 모더니즘의 숙제는 아직 해결되지 않았으므로 Miesianism의 탐구는 Post-Miesianism이라는 새로운 주제로 계속될 것이다. 이를 통하여 21세기 디지털 문명의 시대 속에서 현대건축이 안을 수밖에 없는 보편성과 지역성의 충돌이라는 문제의 해결에 한 발걸음 다가갈 수 있기를 기대하여 본다.