• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.865-867
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• 2001

Generally large synchronous rotating machines with 2 poles have more merits than the others with more than 2 poles Superconducting synchronous rotating machines also have the same tendency, but they have different structure from conventional ones because of no magnetic core inside of the rotor. As the result, design approaches of the superconducting field coils are also different, which would be classified into 2 types according to their coil shapes. The first one is race-track type and the other is saddle type Race-track type machines have almost the same structure with conventional salient pole generators which are being used as largely small scale machines with more than 2 poles. On the other hand saddle type machines correspond to conventional cylindrical generators with 2 poles used for large turbine system in power plants. In this paper several types of superconducting field coils are introduced for 2 pole superconducting machine design and then the feasibility of each type is considered. Moreover, based on the consideration. 1MVA superconducting generator(S.G.) with saddle type field coil is designed electromagnetically.

• Structural Engineering and Mechanics
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• 제62권3호
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• pp.325-344
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• 2017

The present paper investigates the propagation of Love-type wave in a composite structure comprised of imperfectly bonded piezoelectric layer with lower fiber-reinforced half-space with rectangular shaped irregularity at the common interface. Closed-form expression of phase velocity of Love-type wave propagating in the composite structure has been deduced analytically for electrically open and short conditions. Some special cases of the problem have also been studied. It has been found that the obtained results are in well-agreement to the Classical Love wave equation. Significant effects of various parameters viz. irregularity parameter, flexibility imperfectness parameter and viscoelastic imperfectness parameter associated with complex common interface, dielectric constant and piezoelectric coefficient on phase velocity of Love-type wave has been reported. Numerical computations and graphical illustrations have been carried out to demonstrate the deduced results for various cases. Moreover, comparative study has been performed to unravel the effects of the presence of reinforcement and piezoelectricity in the composite structure and also to analyze the existence of irregularity and imperfectness at the common interface of composite structure in context of the present problem which serves as a salient feature of the present study.

• 전기학회논문지
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• 제66권8호
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• pp.1297-1302
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• 2017

Recently, SRMs are used in automobiles for power assistant steering, accessory motion control and traction drives. Especially in the motion control and traction drives, safety and efficiency are of paramount importance. The paper describes the essential elements faced in designing and constructing driving circuits for a switched reluctance motor for automobiles. An important factor in the selection of a motor and a drive for industrial application is the cost. The switched reluctance motor(SRM) is a simple, low-cost, and robust motor suitable for variable-speed as well as servo-type applications. With relatively simple converter and control requirements, the SRM is gaining an increasing attention in the drive industry. This paper presents a modified C-dump converter for Switched Reluctance Motor (SRM) machine application in the cooling system of automobiles. The experiments are performed to verify the capability of applicate control method on 6/4 salient type SRM.

• Nuclear Engineering and Technology
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• 제56권7호
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• pp.2683-2689
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• 2024

This work investigated the most suitable type of degrader (Cu, Al or Nb) and its thickness, taking into consideration the salient aspects of concrete activation for high-purity ⁸⁹Zr production by ⁸⁹Y(p,n)⁸⁹Zr nuclear reaction. The MCNP and FISPACT codes were used to determine the optimal degrader thickness and the radioactivity of shielding concrete by neutron activation, respectively. The results showed that the optimal thickness of the beam degraders was 1.16, 3.19, and 1.33 mm for Cu, Al, and Nb, respectively. The neutron production rate per proton and the energy and angular distributions of neutrons varied depending on the type of degrader. Considering the radioactivity of the target-room concrete and the amount of radioactive waste expected to be generated, the use of a 1.33-mm-thick Nb degrader for ⁸⁹Zr production was determined to be the best choice.

• 한국소음진동공학회논문집
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• 제26권2호
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• pp.165-171
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• 2016

A prosthetic knee for above-knee (AK) amputee is categorized into passive and active type. The passive prosthetic knee is generally made by elastic material. Although AK amputee can easily walk by using passive prosthetic leg, knee joint motions are not similar to ordinary persons. The active prosthetic leg can control the knee angle owing to the actuator and microprocessor. However, the active type is not cost-effective and the stability may be lost due to the malfunction of sensors. In order to resolve these disadvantages of passive and active type, a semi-active prosthetic knee which can control the knee angle is proposed in this work. The proposed semi-active one requires a less input energy but provides active type performance. In order to achieve this goal, in this work, a semi-active prosthetic knee using magneto-rheological (MR) damper for AK amputees is designed. The MR damper can support the weight of body by using less energy than actuator of active prosthetic. It can control knee angle by inducing the magnetic field at the time of stance phase. This salient characteristic is evaluated and presented in this work.

• 가정과삶의질연구
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• 제19권5호
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• pp.147-166
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• 2001

The Purpose of this study was 1) to analyse the attitudes about Elderly Assisted Living (EAL) among urban Korean 2) to consider the policy implications for elderly communal housing. The research methods used were 1) social survey research with questionnaire to find attitudes and preferences about EAL among potential elderly client in Seoul, Korea 2) interpretative suggestion for appropriate policy implications to facilitate developing EAL in urban Korea. A questionnaire was used to find attitudes/preferences about EAL was adapted from the results of the review about communal housing in the UK. The survey was undertaken from September to October, 2000 in Seoul, Korea. Data was collected from 413 subjects and analysed using various statistical techniques. From the results, location should be differentiated into urban type and suburban type. The urban type would prefer around 5 stories multi-family house style with elevator and suburban type would prefer single detached house style with shared garde. The most preferred characteristics found by factor analysis were factor I named as communal facilities and environment(the items belong to factor I was neighbour environment, communal spaces and facilities, heating system, and elevator). The most important advantages of EAL were social activities and convenience. The most salient disadvantages of EAL were difficulty of family contact. The higher the occupational status and income, the lower the preference for the characteristics of EAL with a preference for finding appropriate living arrangements in present housing market. But the higher the educational level, the higher the degree of preference for the characteristics of EAL.

• Ocean Systems Engineering
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• 제9권4호
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• pp.423-448
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• 2019

Very Large Floating Structures (VLFS) are one among the solution to pursue an environmentally friendly and sustainable technology in birthing land from the sea. VLFS are extra-large in size and mostly extra-long in span. VLFS may be classified into two broad categories, namely the pontoon type and semi-submersible type. The pontoon-type VLFS is a flat box structure floating on the sea surface and suitable in regions with lower sea state. The semi-submersible VLFS has a deck raised above the sea level and supported by columns which are connected to submerged pontoons and are subjected to less wave forces. These structures are very flexible compared to other kinds of offshore structures, and its elastic deformations are more important than their rigid body motions. This paper presents hydroelastic analysis carried out on an innovative VLFS called truss pontoon Mobile Offshore Base (MOB) platform concept proposed by Srinivasan and Sundaravadivelu (2013). The truss pontoon MOB is modelled and hydroelastic analysis is carried out using HYDRAN-XR^* for regular 0° waves heading angle. Results are presented for variation of added mass and damping coefficients, diffraction and wave excitation forces, RAOs for translational, rotation and deformational modes and vertical displacement at salient sections with respect to wave periods.

• Journal of Biosystems Engineering
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• 제33권1호
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• pp.7-13
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• 2008

The tillage depth control system is one of the most salient control system of tractor implements. A contact-type height sensor was developed to measure ground clearance for the tillage depth control. The height sensor was fabricated in this study, and its efficacy in a tillage depth control system was evaluated. Experiments were conducted in order to determine both static and dynamic detection characteristics of the height sensor using soil bin system on the sampled soil (sandy loam, sand, clay loam). The results of the static detection characteristics showed that in the case, sandy loam soil despite and clay loam soil at a wet basis moisture content of 30%, large measurement errors were observed a due to penetration of a plastic puck into the sampled soil. The results of the dynamic detection characteristics showed that the height sensor detected the distance from the ground of sandy loam soil despite the uneven nature of the ground surface and the changes in traveling speed $1km/h{\sim}5km/h$ at a wet basis moisture content of 10%.

• 한국과학교육학회지
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• 제32권1호
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• pp.160-181
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• 2012

본 연구의 목적은 과학탐구활동 수행평가 시 총체적 채점의 신뢰도를 높이기 위하여 채점자간 불일치의 정도와 유형을 이해하는 것이다. 이를 위하여 중학생 60명을 대상으로 과학탐구 수행평가를 실시하였고, 4명의 훈련된 채점자 채점을 실시하였다. 분산 분석결과 교사 관련 분산성분에 의해 전체 분산의 25%를 설명할 수 있으며, 4명의 채점자중 2명은 관대한 채점자, 2명은 엄격한 채점자의 경향을 지닌 것으로 나타났다. 전체 240 채점 사례 중 4명의 채점자가 모두 일치한 사례는 51사례이다. 채점자간 불일치가 나타나는 189사례에 대하여 채점자 협의를 통하여 확인한 결과, 채점자간 중요하게 생각하는 부분의 차이 때문에 발생하는 불일치 유형1이 38%, 채점자의 관대함과 엄격함에 의해 발생하는 불일치 유형2가 25%, 채점자가 중요하게 생각하지 않은 부분에서 간과하기 때문에 발생하는 등 실수에 의한 불일치 유형3이 31%로 나타났다. 불일치 유형1은 채점자마다 중요하게 생각하는 과제 요소와 평가 요소가 다른 경우로 나누어서 나타났으며, 맥락상의 의미를 강조하는 채점자는 관대한 경향을, 특정 요소를 강조하여 분석적으로 해석하는 채점자는 엄격한 경향을 나타냈다. 불일치 유형 2는 많은 경우 채점 척도의 경계에 학생의 응답에 대하여 나타났으며, 채점자들은 이러한 학생 응답에 대하여 옳은 서술의 개수를 세는 등 분석적인 채점을 수행하는 것을 확인할 수 있었다. 또한 불일치 유형3은 채점자의 실수로 발생하는 불일치로 주로 학생의 응답 중 평가 기준에 부합하는 부분인데 채점자가 중요하게 생각하지 않기 때문에 간과하여 발생하는 것으로 파악할 수 있었다. 이상과 같은 채점자간 불일치를 제어하기 위해서는 채점자가 중요하게 생각하는 과제 요소와 평가 요소에 대하여 사전 및 진행 중 협의를 할 필요가 있다고 판단된다. 또한 총체적 채점을 하는 경우도 각 수준에 해당하는 평가 기준과 함께 경계에 놓인 학생 응답을 변별하는 기준을 제시하는 것이 필요하다. 채점자들은 자신의 채점경향이 엄격한지 관대한지를 파악하고 경계에 놓인 학생의 응답에 대한 판단을 주의 깊게 하여야 불일치를 줄일 수 있다. 실수에 의한 오차를 줄이기 위해서는 여러 명의 채점자가 교차 채점하는 것이 필요하다. 동일한 채점 기준에 대한 채점자의 해석이 다르게 나타나는 경향과 원인에 대한 추후 연구가 필요하다.

• 복식
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• 제40권
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• pp.95-107
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• 1998

The purpose of this research paper is to offer basic data for cloth design which is intended to apply appropriate shape and catacity to cloth. Followings are the analyzed result of investigation which was conducted to figure out the character of middle aged from 35 to 59 years old-women body especially in lower half of their body. 177 women took part in this investigation. 1. As a result of analyzed characters for middle aged women body shape, taking a side view of body, there are great variance in thickness coefficient which indicates the size of body. 2. According to a comparison result of early middle aged women body shape with late middle aged women body shape, the value in height items get shorter otherwise the value in thickness items get longer getting older. It means late middle aged women are relatively fat. 3. For the analysis of women body especially in lower half, 8 factors were used. They are as followings. Factor 1. Side thickness of lower half. Factor 2. Width of lower half. Factor 3. Height of lower half Factor 4. Droop of underbelly Factor 5. Salient rate of buttocks. Factor 6. Length of buttocks. Factor 7. Salient rate of underbelly. Factor 8. Droop of buttocks 4. Lower half shapes of middle aged women were divided into three groups and the character of each group are as followings. 〈Group 1〉65.0% of women who took part in this investigation have this type of body shape. They have long value in height items and thickness items. 〈Group 2〉16.4% of women who take part in this investigation were belonged to this group. The value in height items were not so different from group 1 but the thickness value are shorter than group 1. Women of group 2 have slime body shape. 〈Group 3〉18.6% of women were belonged to group 3. They show the shortest value in height items otherwise the longest value in thickness items. Therefore they are the smallest and the fattest group in this investigation.