• 전자공학회논문지SC
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• 제39권6호
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• pp.71-78
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• 2002

본 논문은 하프브릿지 컨버터와 포화자심으로 구성되는 간단한 회로에 의하여 소프트스위칭이 가능한 새로운 회로방식을 제안한다. 본 방식에서는 컨버터의 출력단자와 병렬로 각형의 자화특성을 갖는 포화인덕터를 결합하여 컨버터의 온시간과 인덕터의 불포화기간을 일치시킨다. 2개의 MOSFET 스위치에는 짧은 데드타임을 설정하여 그 기간에 자심의 포화인덕턴스와 스위치의 기생용량 성분에 의한 공진을 일으켜 소프트스위칭을 실현시킨다. 또한 전원 전압의 변동에 대처하기 위해 반도체와 선형인덕터를 가지고 자심의 동작을 모의한 새로운 실용회로를 제안한다. 본 논문에서는 포화자심의 모델링의 방법을 통하여 소프트스위칭의 원리를 해석하고 1.25kW의 컨버터에 대한 실험에 의해 그 타당성을 확인하였다.

• 대한한의학원전학회지
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• 제29권2호
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• pp.91-119
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• 2016

Objectives : In this paper, the main objective is to analyze and evaluate Kim Gwangjin(金光鎭, 1885-1940)'s academical achievements of integration of eastern with western medicine and innovation of traditional medicine(TM, 漢醫). Methods : This paper is composed of two parts. First, analyzing Kim's medical book, the principle of Up and Down in Medicine(醫學升降法) by the way of text analysis and interpretation faithfully. Second, adding historical perspectives about his achievements. Results : Kim opened a clinic and practiced TM in Daegu, a city of Youngnam(嶺南) area of Korea, in 1924, and published the book in 1936. While Kim acknowledged the scientific results by western medicine and criticized the typical explanation of five viscera or qi circuits of TM, he clarified the treatment range for TM and provided his own interpretations of pathophysiology through the ups and downs of qi, without conflicting between western medicine and TM. Moreover, he critically follows the TM discourses of the most noted practitioner, Lee Gyoojoon(李圭晙), in the Youngnam area of the time. Conclusions : In the 1930s, although western medicine has become the new core orientation and has forced out TM to the districts, within the abyss of the districts, TM still maintained its strong presence.

• 유통과학연구
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• 제17권12호
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• pp.71-79
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• 2019

Purpose: This study focuses on lean implementation evaluation in Third Party Logistics (TPL) industry by using the lean principles measurement from Toyota Ways which consist of 14 principles. The core goal of this study is to appraise the lean implementation level in Third Party Logistics in East Java of Indonesia in order to achieve efficient logistics, distribution and transportation activities. Research design, data and methodology: This study uses a sample of 80 respondent who are Third Party Logistics managers in East Java Province, Indonesia. Data collection uses a questionnaire and standard statistical test was performed in order to analyze questionnaire. Results: The implementation level of lean management in Third Party Logistics shows that application of principle 3 (utilizing pull systems) has a higher score than the other principles. This situation shows that management give the best performance in plan process. They prioritize customer requirement in every process designed. However, the principle 8 (using reliable technology) show the weakness performance. Conclusions: Overall, this study shows the Third Party Logistics in East Java Province of Indonesia have applied the lean principle quite well, although the scores are only slightly above the average. This condition provides a strong basis for further lean implementation, especially for improving logistics, distribution and transportation activities in Third Party Logistics Business.

• Smart Structures and Systems
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• 제25권4호
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• pp.471-486
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• 2020

Stability analysis of three-layered piezoelectric doubly curved nano shell with accounting size dependency is performed in this paper based on first order shear deformation theory and curvilinear coordinate system relations. The elastic core is integrated with sensor and actuator layers subjected to applied electric potentials. The principle of virtual work is employed for derivation of governing equations of stability. The critical electrical and mechanical buckling loads are evaluated in terms of important parameters of the problem such as size-dependent parameter, two principle angle of doubly curved shell and two parameters of Pasternak's foundation. One can conclude that mechanical buckling loads are decreased with increase of nonlocal parameter while the electrical buckling loads are increased.

• Architectural research
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• 제20권2호
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• pp.45-52
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• 2018

According to previous studies, the form of a city mentioned in Kaogongji(考工記) of Zhouli(周禮) does not exist in reality. Only Beijing during Ming(明) and Qing(淸) Dynasties is discussed as an example, making it lose its worth as a theory. But of all the annotation of Zhouli throughout the 2,000 years before the modern era, core theory related to capital construction had never been stated from the aspect of the present day. Such discussion can be found depicted in Yingzaofashi(營造法式), a specialized book about architectural technology. Unlike what is known until now, the principle of capital construction has a link to the theory of Fengshui(風水), in that it implies the logic of 'Yi(易)'.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.121-126
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• 2005

This paper describes the attributes, performance and development status of a high performance capacitive torque sensor intended for use in a electric power steering (EPS) system. The EPS system is composed of torque sensor, ECU, motor, gears and etc. Among the elements, torque sensor in the steering column is one of the core technologies. The new capacitive torque sensor in this paper is developed differently from working principle and mechanical structure compare to extant torque sensors in market and patent. Based on the result of numerical analysis, a experimental equipment is made which is composed of a test jig and a capacitive sensor and validity of numerical analysis and feasibility of the torque sensor are verified.

• 농업과학연구
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• 제35권1호
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• pp.53-67
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• 2008

The principle goal of environmentally-friendly agriculture is to maintain and conserve water and agriculture environment including drinking water resources by properly using agricultural materials such as agricultural chemicals, chemical fertilizers, and other agricultural materials according to act 19 of foster law of environmentally-friendly agriculture. To achieve these goals, we have to establish Integrated Nutrient Management(INM) and Integrated Pesticide Management(IPM) which are most important core technologies for environmentally-friendly rice cultivation. However, there are lack of criteria and technology for evaluation category according to soil management and its soil classes to practice an environmentally-friendly agriculture. Therefore, we should eatablish the standards to produce the safe agricultural products based on the soil physical and chemical characteristics which are basic properties of soil to accomplish the principle aims of environmentally-friendly agriculture.

• 한국항해학회지
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• 제22권4호
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• pp.21-29
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• 1998

The marine self-organizing VHF data link is a digital radio link with self-organizing ability, which exploits the STDMA algorithm and operates in marine VHF channels. It can support the applications of surveillance, situation awareness and communication. It is the core technology of the Universal AIS which is considered as a future surveillance system at sea by the IMO. In this paper, the operational principle of the marine self-organizing VHF data link is introduced. Simultaneously, a new access protocol is proposed to enhance the marine self-organizing VHF data link so as to support point-to-point communication. The point-to-point communication is one of the most important bases to establish dynamic internetworks among computers on the bridges in the future.

• Wind and Structures
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• 제23권1호
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• pp.59-73
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• 2016

In this paper, a hyperbolic shear deformation beam theory is developed for free vibration analysis of functionally graded (FG) sandwich beams. The theory account for higher-order variation of transverse shear strain through the depth of the beam and satisfies the zero traction boundary conditions on the surfaces of the beam without using shear correction factors. The material properties of the functionally graded sandwich beam are assumed to vary according to power law distribution of the volume fraction of the constituents. The core layer is still homogeneous and made of an isotropic material. Based on the present refined beam theory, the equations of motion are derived from Hamilton's principle. Navier type solution method was used to obtain frequencies. Illustrative examples are given to show the effects of varying gradients and thickness to length ratios on free vibration of functionally graded sandwich beams.

• Structural Engineering and Mechanics
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• 제42권1호
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• pp.39-53
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• 2012

This paper presents an alternative way to derive the exact element stiffness matrix for a beam on Winkler foundation and the fixed-end force vector due to a linearly distributed load. The element flexibility matrix is derived first and forms the core of the exact element stiffness matrix. The governing differential compatibility of the problem is derived using the virtual force principle and solved to obtain the exact moment interpolation functions. The matrix virtual force equation is employed to obtain the exact element flexibility matrix using the exact moment interpolation functions. The so-called "natural" element stiffness matrix is obtained by inverting the exact element flexibility matrix. Two numerical examples are used to verify the accuracy and the efficiency of the natural beam element on Winkler foundation.