• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.113-114
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• 2016

This paper proposes a technical requirements analysis of implementation of multi-trade prefabrication. Recently, there has been a rise in the use of prefabrication to minimize on-site work for time reduction to increase productivity. Prefabrication technique is evolved into multi-trade prefabrication combining other trades from single-trade prefabrication. For implementation of new technique, not only itself but complementary techniques have to be prepared. In this paper, MEP corridor rack, a major item of multi-trade prefabrication, was implemented in the test bed and its process was analyzed to find out technical requirements. As a result, comparatively high level of IT technique was required for efficient use of multi-trade prefabrication in design, lifting and construction phase. In design phase, component level of BIM library was needed for manufacturing; and in lifting phase, BIM-based site logistics process was required. Also in construction phase, laser scanning was implemented for gathering shape and geometry of the wall and slab that were attached to multi-trade prefabrication module.

• 한국해양공학회지
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• 제25권4호
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• pp.1-6
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• 2011

The installation of a topside structure can be categorized into the following stages: start, pre-lifting, lifting, lifted, rotating, positioning, lowering, mating, and end of installation. The transfer of the module onto the floating spar hull occurs in the last three stages, from lowering to the end. The coupled multi-body motions are calculated in both calm water and in irregular waves with a significant wave height (1.52m). The effects of the hydrodynamic interactions between the heavy lifting vessel and the spar hull during the lowering and mating stages are considered. The internal forces caused by the load transfer and ballasting are derived for the mating phases. The results of the internal forces for the calm water condition are compared with those in the irregular sea condition. Although the effect of the pitch motion on the relative vertical motion between the deck of the floating structure and the topside module is significant in the mating phases, the internal force induced pitch motion is too small to have this influence. However, the effect of the internal force on the wave-induced heave responses in the mating phases is noticeable in the irregular sea condition because transfer mass-induced draught changes for the floating structure are observed to have higher amplitudes than the external force induced responses. The impacts of the module on the spar hull in the mating phase are investigated.

• 한국운동역학회지
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• 제14권2호
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• pp.41-55
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• 2004

This study analyzed snatch technique in weight-lifting performed by female gold, silver, and copper medalists at the 75kg level in the 2002 Pusan Asian Games and obtained the following conclusions. 1. KSH used more extensor in the waist than those in ankles, knees, or hip joints during the second pull, So further training is required to manifest both each of joints and waist extensor effectively and thus for the line from shoulders through barbell to hip joints to form a smooth vertical pattern. 2. Contrary to those in other countries, Korean athlete KSH tended to be swift in starting but slow in the second pull section, showing less effectiveness in movement during the second pull; therefore, they must try to exert a swift movement in lockout. 3. KSH showed slowdown in the speed, which was a factor interfering with performance during second pull, despite the great maximum speed of moving barbell. It is important to use barbell sufficiently not to reduce the speed of vertical movement but rather to keep the speed increasing. 4. KSH, who kept doing inefficient movements such as failure to perform swift lockout after lifting the heel at the maximum angle of lower limbs, needs to reduce this meaningless extension of ankles, knees, or hip joints to exert energy effectively.

• 대한조선학회논문집
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• 제52권4호
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• pp.283-289
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• 2015

RGT(Riser Guide Tube) is a part of mooring on the bottom of a turret system to be connected with a production riser, and DBSC(Diverless Bend Stiffener Connector) is a latching component between them. In this paper, appropriate lug arrangement is decided mathematically for the case that a DBSC is lifted and installed on a RGT under the water while FPSO is under construction. Considering asymmetric arrangement & position of RGT and initial lug position, additional lug positions are determined by using an optimization method. The modified installation scheme with new lug points is investigated with a lifting simulation system, SIMSON. The simulation result shows that the installation of DBSC on RGT under the given conditions is quite feasible; therefore the mathematical method is proven to be appropriate.

• 대한물리의학회지
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• 제4권1호
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• pp.9-14
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• 2009

Purpose : The purpose of this study is change of lumbar multifidus muslce recorded simultaneously by ultrasound imaging during upper extremity functional movement in chronic low back pain patients. The subject were consisted of 10 women patients with chronic low back pain and healthy asymptomatic subject 10 women. Methods : 10 women patients with chronic low back pain and healthy asymptomatic subject 10 women is voluntary participated for the research. Subjects were positioned in standing. Multifidus size were measured from L4 vertebral segement. The ultrasound imaging apparatus(Sonoace 6000, Medison, Korea) was epuipped with a 5-MHz convex array transducer. The upper extremity lifting movement used to activate the multifidus was then measured. Results : Results of the analysis showed that at the L4 vertebral leves, healthy asymptomatic subjects had significantly larger multifidus muscle compared with chronic LBP subjects. Conclusion : This study will be used as treatment method of patient with chronic LBP. The multifidus muscle in chronic LBP patients clinical significance. Most of chronic LBP patients have multifidus contraction pattern. Especially multifidus contraction in L4 vertebral segement. So chronic LBP patients necessary multifidus muscle release treatment.

• Journal of Mechanical Science and Technology
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• 제20권10호
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• pp.1753-1764
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• 2006

A U-80 propeller and its modified version, U-75 propeller, are used for a micro air vehicle. The performance characteristics of a U-80 propeller and a U-75 propeller have not much known in the published literature. Thus, their aerodynamic characteristics are investigated using a lifting surface numerical method. The lifting surface method is validated by comparing computed results with measured data in a wind tunnel. From the computed results, it is found that the U-75 propeller produces larger thrust with higher efficiency than the U-80 propeller. To enhance the performance of these propellers, a new propeller is designed by following the sequential design procedures with the design parameters such as hub-tip ratio, maximum camber and its position, and chord length distribution along the radial direction. The performance of the designed propeller is shown to be improved much comparing with those of both the U-80 and U-75 propellers.

• 한국기계가공학회지
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• 제20권4호
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• pp.31-38
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• 2021

In this paper, we proposed an optimal design for determining the shape of a lifting lug freely by applying a multivariate function to the D-type lug, which is commonly used in shipyards. We derived the optimal aspect ratio of the lug through structural analysis and analyzed the safety and behavior of the lug aspect ratio. As a result, two types of final candidates, both lighter than the existing lug weight, were suitable for the ratio. They were found to have the greatest force at an angle of 45 degrees when a load of 100 tons was imposed. When the horizontal and vertical feature ratio of the lug was 1:3, it showed excellent results in terms of safety rates while maintaining weight reduction and functional aspects.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.411-414
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• 2015

The purpose of this study is to conduct a comparative analysis between Korea and the United States of the supply process of unit modular housing at both the factory production phase and the transportation and lifting phase, as part of an attempt to invigorate the unit modular housing market in Korea. Unlike the practice in the United States, one of Korea's unique characteristics is that the floor is constructed with reinforced concrete and hot water heating system. To do this, the wet method in Korea is used that includes concrete placement, curing and constructing hot water floor heating system at the factory production phase, which results in a longer production time and also requires the lifting of heavier loads. In the United States, interior and exterior finishing works of modular housing are performed by different companies, and the distance between the unit module factory and the construction site is quite far. This kind of dualized production structure may cause confusion when it comes to schedule management, procurement management, and stock management. Moreover, problems caused by external environmental factors such as wind and rainfall were reported in the course of long-distance transportation. The results of this case comparison are expected to provide fundamental data that will reduce the amount of trial and error in the unit module production, transportation and lifting work in Korea, which has a comparatively small number of unit modular housing cases.

• International Journal of Naval Architecture and Ocean Engineering
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• 제5권3호
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• pp.431-453
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• 2013

The principal purpose of this paper is to present a novel two phases rational scenario applied in constructing an offshore monopod platform; in which the two phases are the all-ground horizontal construction phase and the post-construction phase. Concerning the all-ground construction phase, a brief investigation of its different stages, i.e., pre-fabrication, fabrication, pre-assembling, positioning, assembling, and surface finishing is introduced. The important practical aspects of such construction phase are investigated without going into the nitty-gritty of the details involved therein. Concerning the post-construction phase, a clear investigation of its sequential stages, i.e., lifting, moving and up-righting is introduced. A finite element model (FEM) of the monopod platform is created to perform the structural analysis necessary to decide the suspension points/devices and the handling scenario during the various stages of the post-construction phase on a rational wise. Such structural analysis is performed within the framework of the three dimensional quasi-static modeling and analysis aiming at simulating the realistic handling condition, and hence introducing a reliable physical interpretation of the numerical results. For the whole effort to be demonstrated efficiently, the results obtained are analyzed, the conclusions are presented, and few related recommendations are suggested.

• 한국건설관리학회논문집
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• 제12권6호
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• pp.120-129
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• 2011

초고층 건축공사에 있어서의 건설리프트 설치는 여러 가지 제한조건들에 의해 한정적인 대수만이 설치될 수 있으며, 이러한 건설리프트의 특징에서 기인하는 설치의 제약은 수직동선 관리에 의해 변화하는 각 층별 노무 생산성에 밀접한 영향을 미치게 된다. 따라서 초고층 건축공사에 있어서의 리프트 운영관리는 현장의 작업생산성을 결정하는 중요한 관리요소이나, 현재 초고층 건축공사의 건설리프트 운영계획의 경우, 각 건설사별 다른 기준을 바탕으로 해당사의 숙련 기술자들의 경험에 의존하는 형태로 계획 및 관리가 이루어지고 있으며, 이러한 관리형태는 프로젝트가 초고층화 및 대형화됨에 따라 고려하지 못하거나 착오가 발생할 수 있는 부분이 생길 수 있는 리스크를 가지고 있다. 이에 본 연구에서는 초고층 건축공사의 중요한 관리요소인 건설리프트 양중관리 시뮬레이션 개발의 일환으로, 건설 리프트의 가감속 능력을 고려한 양중계획 시간산정 알고리즘을 개발하고, 개발된 알고리즘에 대해 시뮬레이션 및 현장측정을 통해 검증하였다.