• 한국패션뷰티학회지
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• 제1권1호
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• pp.105-118
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• 2003

The purpose of this study was to analyze entertainer Byeon Jeong-su's hair styles and thereby, apply the results to models. For the applications, models' hair styles were bisected into two sections, and thereby, the edges of the outsides were cut into solid points, and thereupon, into diverse bases by using vertical section, Perpendicular direction and square angles. On the other hand, the insides were cut in the same way of the outside bases by using radial section, varied combing and $45{\sim}90$ degree head angles. In addition, tops and sides were arranged in their corners, while a graduation technique was used to express a natural difference of levels. The fringes were cut by using free-hand and slicing techniques. furthermore, the quantity and mass of the hairs were treated with such techniques as thinning, swing, effect, rolling, slide and slicing, while a bridge product was used for coloring together with a highlight technique. The hair styles were rendered for straight and wave by using an magic iron machine. It was confirmed through this study that the same cutting techniques would result in different images depending on individuals' physical shapes, facial shapes, head skeletons and types of hairs. Thus, it is required of the hair designers to suggest their own custom hair designs adequate to individuals' images through continued image-wise hair design practices.

• 자원리싸이클링
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• 제20권1호
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• pp.69-79
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• 2011

마그네슘 합금은 비중이 1.74로 가벼운데다 비강도는 구조용 금속 중에서 가장 크며, 방진성, 전자파 차폐성, 저용점 용 여러 가지 장점이 있어 최근 자동차 부품과 전자산업 제품 분야에서 이용이 크게 기대되는 금속이다. 그러나 마그네슘의 결정구조는 조밀 육방정이기 때문에 소성변형이 가능한 슬립면이 한정되어 있으며 압연이나 압출가공 시에는 강한 집합조직이 형성되어 상온가공이 곤란하다. 따라서 지금까지 성형성 개선을 위한 조직제어와 성형기술 분야에서 많은 연구개발이 이루어져 왔다. 본고에서는 결정립과 집합조직에 관한 미세조직의 제어방법, 용체성형, 압연 및 압출에 관한 성형가공 기술과 마그네슘 스크랩 리싸이클링 기술에 관하여 최근의 연구개발 사례를 소개한다.

• 제어로봇시스템학회논문지
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• 제8권5호
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• pp.363-372
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• 2002

In ship operation, the roll motions can seriously degrade the performance of mechanical and personnel effectiveness. So many studies for the roll stabilization system design have been performed and good results have been achieved. In many studies, the stabilizing fins are used. Recently rudders, which have been extensively modified, have been used exclusively to stabilize the roll. But, in the roll stabilization control system, the control performance is very sensitive to the ship speed. So, we can see that it is important to consider the ship speed in the rudder roll control system design. The gain-scheduling control technique is very useful in the control problem incorporating time varying parameters which can be measured in real time. Based on this fact, in this paper we examine the;$H_{\infty}$-Gain Scheduling control design technique. Therefore, we assume that a parameter, the ship speed which can be estimated in real time, is varying and apply the gain-scheduling control technique to design the course keeping and anti-rolling control system far a ship. In this control system, the controller dynamics is adjusted in real-time according to time-varying plant parameters. The simulation result shows that the proposed control strategy is shown to be useful for cases when the ship speed is varying and robust to disturbances like wind and wave.

• 한국소음진동공학회논문집
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• 제15권7호
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• pp.788-798
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• 2005

The monopole theory has long been used to model air-pumped effect from the elastic cavities in car tire. This approach models the change of an air as a Piston moving backward and forward on a spring and equates local air movements exactly with the volume changes of the system. Thus, the monopole theory has a restricted domain of applicability due to the usual assumption of a small amplitude acoustic wave equation and acoustic monopole theory This paper describes an approach to predict the air-pumping noise of a car tyre with CFD/Kirchhoff integral method. The tyre groove is simply modeled as piston-cavity-sliding door geometry and with the aid of CFD technique flow properties in the groove of rolling car tyre are acquired.'rhese unsteady flow data are used as a air-pumping source in the next CFD calculation of full tyre-road geometry. Acoustic far field is predicted from Kirchhoff integral method by using unsteady flow data in space and time which is provided by the CFD calculation of full tyre-road domain. This approach can cover the non-linearity of acoustic monopole theory with the aid of Non-linear governing equation in CFD calculation. The method proposed in this paper is applied to the prediction of air-pumping noise of simply modeled car tyre and through the predicted results, the influence of nonlinear effect on air-pumping noise propagation is investigated.

• 대한기계학회논문집A
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• 제36권4호
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• pp.443-449
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• 2012

Ti-6Al-4V 재에 다양한 표면처리방법을 통하여 나노스킨화된 피로시험편을 제작하고 회전굽힘피로 시험과 축하중 인장압축피로시험을 수행하였다. 특히 S-N 곡선에서 초음파나노표면개질(UNSM)법은 국내특허기술로 다른 처리법들보다 우수한 결과를 보였고, UNSM 처리된 직경 5 mm 재는 6 mm 티타늄재를 대치 가능할 성능을 얻었다. UNSM 처리된 $10^6$ 사이클 이상의 장수명영역에서 피로강도가 크게 향상되는 시험결과를 얻었다. 균열발생 패턴의 분석을 통하여 Ti-6Al-4V 재는 응력의 작용형태에 따라 표면균열발생형(surface originating crack type)과 내부균열발생형(interior originating crack type)인 어안균열(fish eye crack)이 발생하는 메커니즘을 분석하였다.

• Journal of Ship and Ocean Technology
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• 제6권2호
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• pp.23-36
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• 2002

This paper describes the powering, seakeeping and maneuvering performances for a 2,500-ton class trimaran. Influence of the side-hull forms and location of those in longitudinal and transverse direction to resistance performance was systematically investigated by a series of model tests and numerical calculations. It was found that the longitudinal location of side-hulls was the most influential design parameter to the resistance performance of the trimaran and the optimum location of side-hull depends on ship speeds. When the side-hull stem is located near the primary wave hollow generated by the main hull, the trimaran shows the best resistance performance. Powering performance of the trimaran is superior to those of similar mono-hull ships. Seakeeping model tests for the trimaran were executed and the results were compared with the theoretical results of a similar mono-hull ship. Generally speaking, seakeeping performance of the trimaran is superior to that of a mono-hull ship. In particular, pitching and rolling performance of the trimaran is excellent, which is due to the increased length and breadth. Maneuvering model tests using a HPMM equipment were executed to evaluate the maneuvering performance of the trimaran. Maneuvering simulation was performed using the maneuvering coefficients from the model tests. The results show that the control ability of heading angle and the direction keeping stability of the trimaran is excellent, even though the turning performance is rather worse compared to those of a similar mono-hull ship.

• 해양환경안전학회지
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• 제7권3호
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• pp.17-28
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• 2001

The wheelhouse front glass of a Fore-Bridge-Ship (Ro-Ro Ship) was broken by the shipping of water in rough seas, and then the flooding of seawater into the wheelhouse caused the uncontrollable condition of the ship. The hull which was entered into the floating condition rolled severely, and the heavy rolling caused secondary damage such as the collapse of a lot of cargo. It was an incredible accident because the height of bow freeboard was about 2.5 times higher than the standard height of minimum bow freeboard regulated by the International Load Line Convention(1966). And it would be also difficult for navigators to imagine a great deal of seawater flooding into the wheelhouse because the front glass was positioned at about 20m height above the sea surface. In this paper, we carried out the evaluation for the safety navigation of the Fore-Bridge-Ship numerically against ship's speed and encountering angle to the wave in each sea state of rough sea, by using the integrated seakeeping performance index (ISPI) which is able to evaluate synthetically the safety operation of ships. And then the problem on the application of the past criteria proposed as the safety navigation of a merchant ship was clarified by inquiring the dangerousness of the shipping of water at her bow deck, which caused the breakage of the wheelhouse front glass.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2005년도 추계학술대회 논문집
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• pp.69-74
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• 2005

본 연구에서는 선박의 항해 안전성과 정박 중인 선박의 계류 안전성 평가에 기초가 되는 선체운동 평가를 위한 다목적 계측시스템을 개발 하는데 있다. 다목적 계측시스템은 선박에 탑재되어 외력에 의해 발생하는 동적 동요를 계측 및 분석하기 위해 상하, 좌우, 전후방향의 가속도량을 측정하는 3축 가속도 계측기를 포함하여, 방위 센서, 2축 경사계 및 초음파 변위계로 구성하였다. 선박의 항해 및 계류 안전성을 종합적으로 평가하기 위해서는 특정 센서를 이용 선체운동을 실시간으로 측정하여 내항성능 평가 시스템과 항해 또는 정박 중인 선박의 상태에 관한 선박 데이터베이스 시스템을 이용하여 평가한다. 개발된 다목적 계측시스템은 해상에서의 전복사고 분석, 선박 출입항 통제, 부두에서의 하역작업 통제, 조선소에서의 내항성능 및 안전설계에 있어서도 적용이 가능하리라 본다.

• Composites Research
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• 제34권6호
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• pp.350-356
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• 2021

활주 선형의 선박은 직선으로 운항하거나 선회할 때, 그 속도에 따라 위치와 트림이 변화하며, 선체에 큰 저항이 발생한다. 본 논문에서는 탄소복합소재를 선체에 적용하여 선체무게와 내구성이 향상된 레저보트의 전산유체역학을 통해 선형에 대한 저항을 추정하였다. 18ft급 레저보트의 선수부와 선미부의 저항 성능을 확인하고 선형 전체의 유동장을 추정하였으며, 수치해석을 통해 각 트림의 저항을 비교하여 선형에 대한 안정성을 확인하였다. 또한, 선체에 걸리는 힘이 크지 않아 설계된 선형이 충분히 견딜 수 있을 것을 확인하였고, 파도의 파장과 배의 길이를 관성력에 대한 중력의 비로 계산하여 롤링이 얼마의 힘으로 발생하는지 확인하여 보트의 안정성을 분석하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제21권5호
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• pp.94-100
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• 2017

기존의 예인식으로 운용하는 사이드스캔소나의 경우 조사 시 사용자가 원하는 단면 조사에 어려움이 있어 수중구조물 전동 지그가 개발되었지만, 전동지그를 사용한 음파촬영방법의 경우 보트와 소나가 일체 거동하기 때문에 파랑에 의한 보트 롤링현상, 보트운전자의 운용미숙 등으로 인한 음파영상의 흔들림발생 등, 작업환경에 따른 여러 가지 문제로 인하여 데이터의 왜곡이 발생하였다. 따라서 본 연구에서는 기존 사이드스캔소나의 수중조사를 위한 장비운용 시 발생하는 영상의 흔들림을 해결하기 위해, 흔들림 보정센서를 부착하고 흔들림 보정 알고리즘을 개발하여 흔들림보정이 가능하도록 프로그램을 보완하였다. 또한, 소나 데이터 해상도의 향상 정도를 검증하기 위하여, 현장조사를 통해 흔들림 보정 전 후 음파영상을 수집하고 손상 의심부에 잠수사를 투입하여 실제 손상길이 및 수심을 측정하여 취득한 음파영상 데이터의 분석을 수행하였다. 본 연구는 향후 사이드스캔소나를 활용한 구조물의 수중부 및 하상면 음파영상 촬영기법의 발전에 기여할 것으로 판단된다.