• Journal of Chest Surgery
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• 제54권3호
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• pp.186-190
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• 2021

Background: Pre-lifting of the sternum marked a major turning point in pectus excavatum repair. The author developed the crane technique in 2002 and successfully applied it to more than 2,000 cases using sternal wire stitching. However, blind sternal suturing limited the use of the wire-stitch crane. We propose a novel screw for sternal lifting as a new tool for the crane technique. Methods: We developed a screw system strong enough to withstand the pressure needed for sternum lifting. The screw was designed to have a broader thread to hold the bony tissue securely. The screw's sustaining power was tested using the torsion, driving torque, and axial pull-out tests in a polyurethane block and ex-vivo porcine sternum. Results: The screws were easily driven into the sternum, and the head of the screw was connectable to the table-mounted retractor. In the torsion test, the 2° offset torsional yield was 4.53 N·m (reference value, 1 N·m). In the polyurethane block driving torque test, the maximum torque was 0.98 N·m (reference value, 0.70 N·m). The axial pull-out test was 446 N (reference value, 100 N). The maximum pull-out resistance in the ex-vivo porcine sternum model was 1,516 N. Conclusion: The screw crane was strong enough to sustain the chest wall weight to be lifted. Thus, the screws could effectively replace the sternal wire stitching in crane pre-lifting of the sternum. We expect that application of the screw-crane will be easy and that it will improve the safety and success rate of pectus repair surgery.

• 한국해양공학회지
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• 제11권4호
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• pp.249-261
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• 1997

A basic study on the lifting lug design has performed through the rational and systematic process. In order to evaluate the proper design-load distribution around lug eye investigation of contact force between lifting lug and shackle pin is performed using non-linear parametric analysis idealized by gap element models. Gap element modeling and nonlinear analysis procedures are illustrated and discussed based on MSC/NASTRAN. Some analysis and design guides are suggested through the consideration of several important effects such as stress distribution pattern, circumferential contact force distribution along the lug eye face, loading share rate between lug main plate and doubler, effect of loading direction, relation between applied force and deflection and size effect of shackle pin radius. Additionally optimum design studies are performed and general trends according to the variation of design parameters are suggested.

• 대한조선학회 특별논문집
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• 대한조선학회 2005년도 특별논문집
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• pp.165-170
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• 2005

The weight of a ship depends on the size of the ship. Normal lightweight of a ship is over 10,000 tons. So it is inevitable to divide a ship into about more than hundreds of lumps. Each of lumps is called as a block in shipbuilding. The sizes of blocks are decided by a yard's facilities. Among them lifting cranes are most decisive facilities. By block's size the productivity of a yard is decided very much. So it is very important to have a proper block division during shipbuilding. This paper refers to the recent trend of block division among yards. This paper would give an idea how to decide boundaries of blocks. Block division also decides both quality of a ship and work volume of it. These days the block erection method is changed dramatically due to use sea barge mounted crane for erection of a grand ring block. This paper explains the new trend of block division in shipbuilding.

• 대한조선학회논문집
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• 제51권1호
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• pp.42-50
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• 2014

Lifting lugs are frequently used in shipyard to transportate and turn over blocks. As the shipbuilding technology develops, blocks has become bigger and bigger, and block management technology takes a more important role in shipbuilding to enhance the productivity. For the sake of economic as well as safe design of lug structure, more rigorous analysis is needed. In this study in order to investigate the strength characteristics of two type of lug, that is, D and T type lugs, non-linear strength analysis has been carried out to compare the ultimate strength characteristics of two types of lug varying in-plane and out-of-plane loading directions. Based on the present numerical analysis results, it can be drawn that T type lug is superior to D type lug from view points of ultimate strength and deformation.

• 한국해양공학회지
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• 제25권2호
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• pp.101-107
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• 2011

In view of the importance of material reduction because of the jump in oil and steel prices, structural design studies for lifting lugs were performed. Hundreds of thousands of such lifting lug structures are needed every year for ship construction. A direct design study was reviewed using the developed design system to increase the design efficiency and provide a way of directly inserting a designer's decisions into the design system process. In order to understand the design efficiency and convenience of a lug structure, parametric studies for prototype lug shapes were performed using the developed design system. From these design studies, various patterns of design parameters for the lug structure according to changes in the main plate length were examined. Based on these parametric study results, design guides were developed for more efficiently suggesting structural data for enormous lug structures. Additionally, a more detailed structural analysis through local strength evaluations will be performed to verify the efficiency of the optimum structural design for a lug structure.

• 한국인터넷방송통신학회논문지
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• 제23권6호
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• pp.75-80
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• 2023

미래의 무선과 휴대용 계산 응용에서 DCT 대체할 수 있는 가역적인 블록 변환의 구현을 제시하였다. 이것을 binDCT라 불린다. BinDCT에서 정방향과 역방향 변환들은 이진 천이와 더하기 연산으로 구현될 수 있다. 그리고 binDCT는 바람직한 DCT 특징인(고코딩이득, DC손실 없음, 대칭적인 기저함수, 재귀적 구성)을 유지한다. 또한 binDCT는 lifting 특징인(빠른 구현, 가역적인 정수대정수 매핑, 내부 계산)을 유지한다. 따라서 복잡한 DCT 연산을 보다 빠르게 실행할 수 있는 장점을 가진다. 이 논문에서는 DCT와 binDCT의 계산비용과 성능분석을 Shapiro의 EZW을 사용하여 제시하였다.

• 한국통신학회논문지
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• 제27권8A호
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• pp.814-821
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• 2002

SPIHT(set partitioning in hierarchical tree)는 제로트리 알고리즘 중 효율적이며 잘 알려져 있다. 그러나 높은 메모리 요구로 인해 하드웨어 구현에 큰 어려움을 가지고 있다. 본 논문에서는 저 메모리 사용과 빠른 제로트리 부호화 알고리즘을 제안한다. 메모리를 줄이고 빠른 코딩을 위한 방법으로 다음 3가지를 제안한다. 첫 번째, 리프팅(lifting)을 이용한 웨이블릿(wavelet) 변환은 기존의 필터뱅크 방식의 변환보다 저 메모리와 계산량의 감소를 가진다. 두 번째 방법은 웨이블릿 계수들을 블록으로 나누어 각각 부호화 한다. 여기서 블록은 제로트리 구조가 유지되는 STB(spatial tree-based block)이다. 마지막으로 Wheeler와 Pearlmandl 제안한 NLS(no list SPIHT)를 이용한 부호화이다. NLS의 효율성은 SPIHT와 거의 같으며 작고 고정된 메모리와 빠른 부호화 속도를 보여준다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.19.1-19.4
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• 2016

Background: Implant surgery has become popular with the advance of surgical techniques such as sinus lifting, guided bone regeneration, and block bone graft. However, there were no data about the frequency of bone graft during implant surgery. The purpose of this study was to report the frequency and types of bone graft depending on dental implant patients' profile to complement the database regarding implant surgery. Methods: The implant operations had been performed from January 2006 to October 2014. The upper and lower jaws were divided into six sextants. A total of 792 sextants were included in this study. Patient information including sex, age, sites, bone graft, and types of bone were investigated. Results: A total of 1512 implants had been placed. Male and female sextants were 421 and 371, respectively (M:F = 1:0.88). Average age was 54.3 (ranging from 20 to 88 years old). Implants were placed in the posterior maxilla (322 sextants, 40.7 %), posterior mandible (286 sextants, 36.1 %), anterior maxilla (127 sextants, 16.1 %), and anterior mandible (57 sextants, 7.2 %). Bone graft was performed in 50.3 % of the sextants. Among the bone grafted sites, sinus lifting with lateral approach (22.1 %) and guided bone regeneration (22.7 %) were performed most frequently. Conclusions: Bone graft in implant surgery was necessary to augment defects. More than half of the sextants needed bone graft for implant installation.

• Journal of Ship and Ocean Technology
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• 제10권4호
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• pp.1-11
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• 2006

The finite volume based multi-block RANS code, WAVIS developed at MOERI is applied to the numerical self-propulsion test. WAVIS uses the cell-centered finite volume method for discretization of the governing equations. The realizable $k-{\epsilon}$ turbulence model with a wall function is employed for the turbulence closure. The free surface is captured with the two-phase level set method and body forces are used to model the effects of a propeller without resolving the detail blade flow. The propeller forces are obtained using an unsteady lifting surface method based on potential flow theory. The numerical procedure followed the self-propulsion model experiment based on the 1978 ITTC performance prediction method. The self-propulsion point is obtained iteratively through balancing the propeller thrust, the ship hull resistance and towing force that is correction for Reynolds number difference between the model and full scale. The unsteady lifting surface code is also iterated until the propeller induced velocity is converged in order to obtain the propeller force. The self-propulsion characteristics such as thrust deduction, wake fraction, propeller efficiency, and hull efficiency are compared with the experimental data of the practical container ship. The present paper shows that hybrid RANS and potential flow based numerical method is promising to predict the self-propulsion parameters of practical ships as a useful tool for the hull form and propeller design.

• 대한전자공학회논문지SD
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• 제41권8호
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• pp.75-84
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• 2004

본 논문에서는 Motion JPEG2000 등의 이산 웨이블릿 기반의 고속 영상처리를 위해서 리프팅 방식의 효율적인 H/W 구조를 제안하였다. 리프팅 내부연산의 반복성을 이용하여 알고리즘 레벨에서 구조적인 사상을 적용하고 데이터 스케줄링을 이용하여 최적화되고 간략화된 리프팅 기반의 필터링 셀의 구조를 제안한다. 이를 바탕으로 (9,7) 및 (5,3) 필터를 모두 수용할 수 있는 리프팅 커널의 구조를 구현하였다. 제안된 리프팅 커널은 일정 대기지연 시간 후에 연속적으로 데이터를 출력할 수 있는 간략화된 구조를 갖고 있다. 시간적인 순서로 입력되는 데이터에 대해서 일정한 출력을 발생할 수 있기 때문에 단순히 H/W를 추가하면 병렬적인 동작을 통해서 높은 출력율을 간단히 얻을 수 있다. 본 논문에서 제안된 리프팅 커널은 ASIC 및 FPGA 환경으로 모두 구현하였는데, ASIC으로는 삼성전자의 0.35㎛ CMOS 라이브러리를 이용하여 구현하였고 FPGA은 Altera사의 APEX을 타겟으로 하였다. ASIC의 경우 리프팅 연산을 위해 41,592개의 게이트 수와 라인 버퍼링을 위한 128Kbit의 메모리를 사용하였으며, FPGA의 경우 6,520개의 LE(Logic Element)와 128개의 ESB(Embedded System Block)을 사용하였다. 각각의 경우에 대해서 125MHz와 52MHz의 속도에서 안정적으로 동작할 수 있었다.