• International Journal of Control, Automation, and Systems
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• 제4권4호
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• pp.495-505
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• 2006

A class of robust control for flexible joint manipulators with nonlinearity mismatched uncertainty is designed based on Lyapunov approach. The uncertainties are unknown but their values are within certain prescribed sets. No statistic information of the uncertainties is imposed. The control which utilizes state transformation via virtual control is proposed. The resulting robust control guarantees practical stability for the transformed system and later the stability for the original system is proved. The designed robust control is implemented by experiments in a 2-link flexible joint manipulator.

• 한국기계가공학회지
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• 제16권1호
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• pp.102-111
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• 2017

An automobile ball joint is the element for connecting the control arm and the knuckle arm, allowing rotational motion. The ball joint consists of the stud, plug, socket, and seat. These components are assembled through the caulking process that consists of plugging and spinning. In the existing research, the pull-out strength and gap stiffness were calculated, but we did not consider the uncertainties due to the numerical analysis and production. In this study, the uncertainties of material property and tolerance are considered to predict the distributions of pull-out strength and gap stiffness. Also, pull-out strength and gap stiffness are predicted as the a distribution rather than one deterministic value. Furthermore, a robust design applying the Taguchi method is suggested.

• 수산경영론집
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• 제24권2호
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• pp.83-97
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• 1993

Since the last decade, the fisheries industry in Korea has faced many difficulties in terms of comparative economic advantage partly because of marine environmental damage caused by Pollution and coastal reclamation, and partly because of too expensive production factors like labor. In addition, new order of world trade created by Uruguay Round will force the Korean fisheries industry to prepare some remedies including a joint-venture business with China for international compatativeness. As a result, this paper mainly deals with an analysis on feasibility of Sino-Korean joint cooperation in fisheries business. Especially, the Shandong Province in China is expected to take advantage of its geographical proximity to Koreas well as of its abundance in marine natural resources in order to achieve a fast economic growth. Thus, for the next decade to come, it would be very important for the Korean fisheries industry to cope with the international fisheries market by the Sino-Korean joint-venture combining the capital and technology from Korea with the cheap labor and favorable marine environment for aquaculture from China.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2000년도 추계 학술대회지
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• pp.46-78
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• 2000

This paper is to introduce recent collaborative activities in agricultural weather information services among institutions in Korea as well as key concepts for understanding agrometeorological services. KMA and RDA have agreed upon the establishment of the Joint Committee for Agrometeorolgy at national level to strengthen the national agrometeorological services in data collection, information production, research, and services to end-users of agrometeorological information in Korea. Several on-going joint projects in agrometeorology by RDA/KMA are introduced in brief. The projects being developed are : Strengthening of the Joint Committee of agrometeorology, Extension of observation network for agricultural weather, Production of the detailed agrometeorological information based on numerical weather forecasts, Development of seasonal and interannual weather forecasts for agricultural applications, Information network system for supporting agrometeorological research, and Improvement of agrometeorological information services at national and regional level. Strengthening of programs for the education and training of agrometeorologists will be impending responsibilities of the government. The government must consider establishment of organizations dedicated to and in charge of national agrometeorological services to end-users. RDA and KMA should play a major role to obtain this goal, based on a close cooperation with universities, scientific societies, and other relevant institutions. If this plan is successful, major infrastructures and services in agrometeorology shall be established in the next 5 years, and we can contribute to regional and global societies through sharing experiences and know-hows.

• 대한물리치료과학회지
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• 제24권1호
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• pp.69-78
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• 2017

Background: The purpose of the present study is to report the effect of muscle performance on knee flexion and extension by chin in exercise. Methods: This study was Participated in 10 healthy subjects. For conducting the chin-in exercise, subjects are lay down with supine position. Using the rounded towel, subjects was performed contraction of longus colli and longus capatis muscle by push the towel. Chin-in exercise was conducted 3 times a day, 4 times a week for 4 weeks. By using the Biodex system4, We measured absolute muscle strength, relative muscle strength, total exercise quantity and average rate of production in knee flexion and extension. The data was analyzed by the repeated-measure ANOVA for comparing before, after exercise 2 weeks, after exercise 4 weeks changes of factors. Results: After chin-in exercise, there was significant difference of before, after 2 weeks and 4weeks results in absolute muscle strength, relative muscle strength, total exercise quantity, average rate of production, agonist/antagonist ratio(p<.05). Conclusion: As a results of this study, chin-in exercise may help to improve muscle ability of knee joint activation and knee joint action performance.

• 한국항공우주학회지
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• 제41권12호
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• pp.967-974
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• 2013

저자는 최근 산업체 생산 현장에서 Z-피닝 복합재 구조물을 간편하게 제작할 수 있는 Z-피닝 패치 개념을 제안하였고, 이를 적용하여 복합재 단일-겹침 전단 접합시편을 제작하였으며, 정적시험을 통하여 54~68%의 접합강도의 향상을 발표하였다. 본 연구는 상기 연구의 후속으로서, 반복하중에 대한 접합강도의 향상을 측정하기 위하여 피로시험을 수행하였다. 사용된 Z-핀은 스테인레스강 핀이며, 복합재료와의 결합력을 증가시키기 위하여 표면을 요철 형상으로 가공하였으며, 화학적으로 부식시켰다. 반복하중 조건에서 접합강도는 약 98~125% 향상되었다.

• 화약ㆍ발파
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• 제36권4호
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• pp.9-15
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• 2018

발파에 의한 암석의 파쇄도는 적재, 운반과 2차 파쇄로 이어지는 후속공정에 직접적인 영향을 미치므로 파쇄도의 조절은 발파 효율성과 생산비용을 평가하는데 필수적이다. 본 연구에서는 인공절리의 방향에 따른 암석의 파쇄도에 대해 분석하였다. 갱내 암반에 수직 및 수평인공절리를 생성한 후 발파실험을 수행하였다. 생성된 암석파쇄물의 입도분포는 2차원 영상해석 프로그램인 split-desktop으로 평가하였다. 평가결과 수평인공절리가 수직인공절리에 비해 전체적인 암석파쇄물의 크기가 작게 평가되었고, 다양한 크기로 암석파쇄물이 분포하였다. 인공절리의 방향에 따라 대괴발생을 억제하고 암석파쇄물을 일정한 크기 이하로 조절 할 수 있을 것으로 판단된다.

• 대한산업공학회지
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• 제36권4호
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• pp.243-247
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• 2010

Every products, which made by mass production, is not identical in their size but have variations in some intervals specified by tolerance dimensions. Tolerances play major role in standardization of part and its quality, and also make a huge impact on manufacturing cost. The optimal condition for tolerances is giving the values as loose as possible for low production cost while satisfying quality specification, which usually demand tight control of tolerances. Tolerance analysis is necessary to get an optimal solution for this conflict situation. This paper have studied tolerance analysis for universal joint assembly of vehicle steering system and tried to find useful results of the study for product design and quality control.

• 지역연구
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• 제14권2호
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• pp.51-64
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• 1998

This paper investigates how the factor inputs of firms are affected by the expectation about land-price increase in the future. We develope a two-factor (land and labor) model, in which expectation about land-price increase plays a key role in determining the "optimal" input level of labor and land. Expecting capital gains from input of the land when land price increases, firms input land up to the point where the marginal productivity of land falls short of the marginal cost of purchasing the land, in order to maximize the "joint-profit". That is, firms have an incentive to use more land than they do when capital gains are not expected. We mean joint-profit by profit in the standard sense plus capital gains. Once the land is input "excessively", the productivity of labor increase and labor is also input more, since land and labor are assumed as complementary in production. This mechanism works in the opposite direction when land price decrease. This paper suggests that land price fluctuation is a major destabilizer of an economy.or destabilizer of an economy.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.439-449
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• 2002

This paper reviews our recent research works on the interconnection technologies in electronic packaging and assembly. At the aspect of advanced joining methods, laser-ultrasonic fluxless soldering technology was proposed. The characteristic of this technology is that the oxide film was removed through the vibration excitated by high frequency laser change in the molten solder droplet. Application researches of laser soldering technology on solder bumping of BGA packages were carried out. Furthermore, interfacial reaction between SnPb eutectic solder and Au/Ni/Cu pad during laser reflow was analyzed. At the aspect of soldered joints' reliability, the system for predicting and analyzing SMT solder joint shape and reliability(PSAR) has been designed. Optimization design method of soldered joints' structure was brought forward after the investigation of fatigue failure of RC chip devices and BGA packages under temperature cyclic conditions with FEM analysis and experimental study. At the aspect of solder alloy design, alloy design method based on quantum was proposed. The macroproperties such as melting point, wettability and strength were described by the electron parameters. In this way, a great deal of the experimental investigations was replaced, so as to realize the design and research of any kinds of solder alloys with low cost and high efficiency.