• 한국토양비료학회지
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• 제34권1호
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• pp.42-54
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• 2001

질소비료는 작물의 생장에 있어서 가장 핵심적인 영양소라 할 수 있으며, 질소의 효율적 이용은 안정적인 수확량의 확보 뿐만 아니라 비용절감 및 환경오염원 감축 등 다양한 편익을 제공할 수 있을 것이다. 정밀농업은 토양의 특성에 따라 작물에 필요한 적정량의 시비로 영양분의 이용효율을 높임으로써 환경 경제적 편익을 동시에 추구하는 농법이라 할 수 있다. 본 연구는 GIS를 이용하여 구축한 455개 표본농경지의 토양 및 지형에 관한 Database에 근거하여 각 농경지내에서 토양을 세분하여 적정 시비를 할 경우(site-specific management)와 농경지별 적정 시비를 하였을 경우(uniform rate application) 비료의 사용량, 수확량, 수질오염 정도 등을 EPIC모델을 이용하여 비교분석 하였다. 전체 농경지에서의 가중평균적인 환경 경제적 효과는 큰 차이를 보이지 않지만 각각의 농경지가 다양한 토양으로 구성되어 있고 다양한 토양에 대한 최적의 질소량이 큰 차이를 나타낼 때는 정밀농업의 실천이 경제적 및 환경적 측면에서 충분한 잠재력이 있는 것으로 나타났다.

• 대한기계학회논문집
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• 제16권1호
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• pp.63-69
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• 1992

본 연구에서는 특히 앞서 지적한 표면균열의 진전거동에 관한 연구와도 관련 하여 측면홈을 가진 중앙관통균열(side-grooved center cracked tension) 시험편에 대 해 피로균열 진전실험을 수행하고, 평면변형률 조건의 만족여부 및 응력강도계수 평가 방법에 관하여 검토하여 비교적 새로운 결과를 얻었으므로 여기에 보고하고자 한다.

• 한국정밀공학회지
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• 제28권7호
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• pp.769-776
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• 2011

In order to cope with the requirements of smaller patterns, larger surfaces and lower costs in the fields of displays, optics and energy, greater attentions is now being paid to the development of micro-pattern machining technology. Compared with flat molds, roll molds have the advantages of short delivery, ease of manufacturing larger surfaces, and continuous molding. This paper presents the state-of-the-art of the micro pattern machining technology on the roll molds and introduces some research results on the machining process technology. The copper and nickel-phosphorous-alloy plating process, machining process technology for uniform micro patterns. micro cutting simulation and the real time monitoring system for micro machining are summarized. The developed technologies have led the complete localization of the prism sheets and will be applied to the direct forming process with succeeding research & development.

• Journal of Astronomy and Space Sciences
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• 제37권3호
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• pp.199-208
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• 2020

This paper presents a kinematic ephemeris generator for Korea Pathfinder Lunar Orbiter (KPLO) and its performance test results. The kinematic ephemeris generator consists of a ground ephemeris compressor and an onboard ephemeris calculator. The ground ephemeris compressor has to compress desired orbit propagation data by using an interpolation method in a ground system. The onboard ephemeris calculator can generate spacecraft ephemeris and the Sun/Moon ephemeris in onboard computer of the KPLO. Among many interpolation methods, polynomial interpolation with uniform node, Chebyshev interpolation, Hermite interpolation are tested for their performances. As a result of the test, it is shown that all the methods have some cases that meet requirements but there are some performance differences. It is also confirmed that, the Chebyshev interpolation shows better performance than other methods for spacecraft ephemeris generation, and the polynomial interpolation with uniform nodes yields good performance for the Sun/Moon ephemeris generation. Based on these results, a Kinematic ephemeris generator is developed for the KPLO mission. Then, the developed ephemeris generator can find an approximating function using interpolation method considering the size and accuracy of the data to be transmitted.

• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1864-1871
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• 2017

This paper presents a design of a 2-phase segmental stator type 4/3 switched reluctance motor (SRM) for air-blower application. The air-blower requires only one direction rotation, high rotor speed without torque dead-zone. In order to satisfy the requirements of the load, the rotor of the 4/3 proposed SRM is designed with wider rotor pole arc and non-uniform air-gap is applied on the rotor shape. With a special rotor structure, the motor generates a wider positive torque region and has no torque dead-zone. The stator of the proposed SRM is constructed with two segmental C-cores, and there are no magnetic connections between 2 C-cores. The flux follows in a short closed loop in each C-core and has no reversal flux in the stator. The static and dynamic characteristics of the proposed motor are analyzed by the finite element method (FEA) and Matlab-Simulink, respectively. In order to verify the design, a prototype of the proposed motor has manufactured for laboratory test. The performance of the proposed motor is verified by the simulation and experimental results.

• 한국도서관정보학회지
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• 제36권2호
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• pp.221-239
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• 2005

FRBR(Functional Requirements for Bibliographic Records)은 개체-관계형 모델을 기반으로한 서지 정보의 새로운 개념 모델로 향후 개정될 AACR 3의 기본 개념으로 자리잡고 있다. JSC(Joint Steering Committee for Revision of AACR)는 FRBR 개념을 수용하기 위한 다각도의 작업을 진행하고 있으며, 특히, 표현형 계층 문제를 해결하기 위하여 통일 표제의 전면적인 용도 변경과 GMD(General Material Designation)의 개선을 건의한 상황이다. 본 연구에서는 FRBR의 발전 과정과 표현형 계층의 문제점을 분석하고 FRBR 개념 수용을 위한 AACR3의 개정 방향을 고찰한다. 또한 이러한 세계적 흐름에 따른 우리 목록 규칙과 목록 레코드의 실제 작성 현황을 분석하고 문제점과 앞으로의 발전 방향을 모색해 본다.

• 복식문화연구
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• 제28권3호
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• pp.344-355
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• 2020

The purpose of this study was to develop a workwear design that takes into account the characteristics of people with severe developmental disabilities who can engage in vocational activities. The aim was to identify needs according to the specific characteristics of people with severe disabilities to design work clothes and develop products according to universal design guidelines. This research method was conducted through representative interviews from a company employing people with severe dis- abilities in Daegu to determine the requirements for workers-related work clothes, and then applied universal design guidelines to perform appropriate design. The results of the study show that the hygiene and warmth of clothing are important for people with developmental disabilities. Therefore, the use of bright materials is required. Second, people with brain lesions often have low body temperature due to difficulties with blood circulation, for which warmth is a required factor. Third, people with severe developmental disabilities should not be differentiated in comparison to people without disabilities, therefore, it was important to use nondiscriminatory designs. Accordingly, it was more efficient to modify and supplement clothing designed for non-disabled people with hidden functions to suit specific characteristics, rather than to develop specialized clothing. These demands were found to conform to what is referred to as a universal design concept, through which three nondiscriminatory shirt designs and two easy-to-use pants were designed.

• 대한기계학회논문집B
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• 제30권6호
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• pp.594-601
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• 2006

Optimization study has been carried out to design an energy efficient, high temperature vacuum furnace which satisfies users' design requirements. First of all, the transient temperature distribution and the uniform temperature zone results have been compared with the steady state results to validate the feasibility of using steady state solution when constructing the thermal analysis DB. In order to check the accuracy, the interpolated results using thermal analysis DB have been compared with the computational and the experimental results. In this study, total heat flux is selected as the objective function, and the geometry parameters of vacuum furnace including the thickness of insulator, the heat zone sizes and the interval between heater and insulator are the design variables. The Uniform temperature zone sizes and the wall temperature are imposed as the design constraints. With negligible computational cost a high temperature vacuum furnace which has $40\sim60%$ reduction in total heat flux is designed using thermal analysis DB.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1978-1985
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• 2018

In this paper, a novel single-phase hybrid switched reluctance motor (HSRM) is proposed for hammer breaker application. The hammer breaker requires only unidirectional rotation and high-speed operation. To satisfy the requirements and eliminate torque dead-zone, the rotor of the proposed 4/4 poles SRM is designed with wider pole arc and non-uniform air-gap. This motor has a simple structure and produces low torque ripple. Permanent magnets (PMs) are mounted on the inner stator at a certain position which enables it to park the rotor for self-start and create positive cogging torque in the torque dead-zone. Compared with conventional single-phase switched reluctance motor, HSRM has an increased torque density and relatively low torque ripple. To verify effectiveness, finite element method (FEM) is employed to analyze the performance of the proposed structure. Then, the proposed motor is compared with the existing motor drive system for the same application. The proposed HSRM is easy to manufacture along with competitive performance.

• Journal of information and communication convergence engineering
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• 제1권3호
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• pp.133-138
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• 2003

The preparation of $Al_{2}O_{3}-SiO_{2}$ thin films from less than one micron to several tens of microns in thickness had been prepared from metal alkoxide sols. Two methods, dip-withdrawal and electrophoretic deposition, were employed for thin films and sheets formation. The requirements to be satisfied by the solution for preparing uniform and strong films and by the factors affecting thickness and other properties of the films were examined. For the preparation of thin, continuous $Al_{2}O_{3}-SiO_{2}$ films, therefore, metal-organic-derived precursor solutions contained Si and Al in a chemically polymerized form has been developed and produced in a clear liquid state. In the process of applying to substrates, this liquid left a transparent, continuous film that could be converted to crystalline $Al_{2}O_{3}-SiO_{2}$ upon heating to $1000^{\circ}C$. And, a significant change of the film density took place in the crystallization process, thus leading to the strict requirements as to the film thickness, which could survive crystallization.