• Composites Research
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• v.37 no.3
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• pp.170-178
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• 2024

This study proposes a hybrid composite where a thin copper film (Cu film) is embedded in carbon fiber reinforced plastic (CFRP), and quantum annealing is applied to derive the combination of Cu film placement that maximizes the through-thickness thermal conductivity. The correlation between each ply of CFRP and the Cu film is analyzed through finite element analysis, and based on the results, a combination optimization problem is formulated. A formalization process is conducted to embed the defined problem into quantum annealing, resulting in the formulation of objective functions and constraints regarding the quantity of Cu films that can be inserted into each ply of CFRP. The formulated equations are programmed using Ocean SDK (Software Development Kit) and Leap to be embedded into D-Wave quantum annealer. Through the quantum annealing process, the optimal arrangement of Cu films that satisfies the maximum through-thickness thermal conductivity is determined. The resulting arrangements exhibit simpler patterns as the quantity of insertable Cu films decreases, while more intricate arrangements are observed as the quantity increases. The optimal combinations generated according to the quantity of Cu film placement illustrate the inherent thermal conductivity pathways in the thickness direction, indicating that the transverse placement freedom of the Cu film can significantly affect the results of through-thickness thermal conductivity.

• Composites Research
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• v.36 no.6
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• pp.454-460
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• 2023

Recently, regulations on greenhouse gas emissions have been strengthened, and the International Maritime Organization (IMO) has been strengthening greenhouse gas regulations with a goal of net 'zero' emissions by 2050. In addition, in the shipbuilding/offshore sector, it is important to reduce operating costs, such as improving propulsion efficiency and lightening structures. In this regard, research is currently being conducted on topology optimization using 3D printed composite materials to satisfy structural lightness and high rigidity. In this study, three topology shapes (hexagonal, square, and triangular) were applied to the interior of a rudder, a ship structure, using 3D printed composite materials. Structural analysis was performed to determine the appropriate shape for the rudder. CFD analysis was performed at 10° intervals from 0° to 30° for each rudder angle under the condition of 8 knots, and the load conditions were set based on the CFD analysis results. As a result of the structural analysis considering the internal topology shape of the rudder, it was confirmed that the triangular, square, and hexagonal topology shapes have excellent performance. The rudder with a square topology shape weighs 78.5% of the rudder with a triangular shape, and the square topology shape is considered to superior in terms of weight reduction.

• Korean Journal of Labor Studies
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• v.17 no.1
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• pp.269-295
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• 2011

This paper is about the part-time work and related polices in Netherland, which increased the employment rate for the past 30 years with part-time job creation. Netherland has been successful in making part-time 'good' jobs. There were many factors which contributed to increaing part-time jobs such as market, institution, policies, and industrial relations. There was virtuous cycle between increase in the supply of female labor power and increase in the demand for part-time worker in the labor market. The policies were reinforced which protect part-time workers, introduced the incentive system which was favorable to part-time wokres, guaranteed the right to select working hours to workers. Particularly, the labor market, institutions and policies were created in the midst of the social dialogue. As the polder model has been persisted for almost 30 years, the switch to full-time work or long working-hour model would not be possible. As the poler model is a very specific model based on the Netherland's own social conditions, it is not easy to copy and transplant in other countries.

• KOMUNHWA
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• no.56
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• pp.215-245
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• 2000

필자는 이 글을 통해 제주도 고고학 발달사를 크게 4기로 구분하여 보았다. 제1기는 1945년 이전 일제강점기에 유적과 유물을 단순하게 보고하는 수준에 머물렀던 시기이고 제2기는 1945년에서 1983년 기간으로 향토사가와 한국 본토의 고고$\cdot$역사학자들의 부분적인 학술조사가 있었던 시기이다. 따라서 1$\~$2기는 제주 고고학의 기본적인 틀을 잡지 못한 단계라고 할 수 있다. 제3기는 1984년부터 1995년까지로 제주고고학에 있어 본격적인 발굴이 진행되지만 대부분이 긴급 발굴에 해당하고 소규모적인 발굴이었다. 하지만 이 시기에 와서 그 동안 발굴했던 자료와 그 이전의 발굴자료를 모아 나름대로 제주고고학의 시대 편년, 문화 변천 등의 기본적인 틀과 방향을 설정한 시기이기도 하다. 제4기는 1996년 이후 현재까지로 제주고고학의 기본적인 틀 속에서 이를 보완하고 새로운 선사문화의 단계를 설정하는 연구들이 진행 중이다. 이를 뒷받침하는 계기는 제주 고산리유적, 삼양동유적 등이 연차적, 계획적, 대대적으로 발굴되면서 많은 자료가 나왔기 때문이다. 또한 고고학의 범위가 선사시대에 국한되지 않고 제주목관아지, 성읍객사지, 법화사지, 존자암지, 수정사지, 고내현청터 등 역사유적의 출토자료에 대한 관심이 더욱 집중되기에 이르렀다. 제주도내 매장문화재는 발굴된 유적 대부분이 지정되어 있는 상태이다. 제주목관아지(사적 390호), 항파두리성(사적 396호), 고산리유적(사적 412호), 삼양동유적(사적 416호)로 지정되었다. 제주도 지석묘는 총 24기가 지방기념물로 지정되어 있으며 발굴했던 선사유적 중 곽지패총, 북촌리바위그늘집자리, 용담동무덤유적이 지정되어 있다. 역사유적 중 법화사지, 존자암지가 지정되었고 일부 유적지는 복원 중이다. 제주도 문화재를 보존하고 활용하기 위해서는 강화된 새로운 문화재법의 적절한 활용, 매장문화재 발굴 전문기관 설립, 발굴된 문화재의 원상보존, 문화재 주소록 작성, 문화재 행정 전문인력의 확보, 제주문화재의 상징물 선정과 활용, 지역문화재홍보위원의 위촉과 다양한 문화유산 프로그램의 개발을 들었다.

• Korean Journal of Heritage: History & Science
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• v.47 no.3
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• pp.108-127
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• 2014

Gangwha was a capital city of Goryeo, in spite of short-term occupation, where various national facilities such as palace stood in a row. Nevertheless, its historic importance has been undervalued owing to undiscovered palace. According to ${\ll}Goryeosa{\gg}$, palace in Gangwha was built in imitation of that of Gaegyeong. If it is true, the site of the old palace in Gaeseong as an original could give significant information for that of Gangwha. The distinct feature of Gaegyeong is that the palace was located in the west area of the centerline from north to south and pond lay in the east side. There is a mountain in the center of capital and two rivers runs along side the mountain. Gunggol at Gwancheong-ri is a best place where structural peculiarities of Gaegyeong can be applicable to Gangwha. There is an area of celadon distribution and is some topographic similarities such as central mountain, two rivers are quite similar. It is assumable that excavation result of no. 405 Gwancheongri reflects the function of east pond and thoroughfare responds to main street from north to south of Gaegyeong. After all the analysis from archaeological information, old maps, cadastral maps, topographic similarities and so on, Gunggol at Gwancheong-ri within an arc shape road is a most suitable place as palace in Gangwha.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.6 s.177
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• pp.1456-1469
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• 2000

Mechanical behaviors of uniaxially fiber-reinforced metal matrix composites under transverse loading conditions were studied at room and elevated temperatures. A mono-filament composite was selecte d as a representative analysis model with perfectly bonded fiber/matrix interface assumption. The elastic-plastic and visco-plastic models were investigated by both theoretical and numerical methods. The product of triaxiality factor and effective strain as well as stress components and strain energy was obtained as a function of location to estimate the failure sites in fiber-reinforced metal matrix composite. Results showed that fiber/ matrix interfacial debond plays a key role for local failure at the room temperature, while void creation and growth in addition to the interfacial debond are major concerns at the elevated temperature. It was also shown that there would be an optimal diameter of fiber for the strong fiber-reinforced metal matrix composite.

• Composites Research
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• v.29 no.2
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• pp.66-72
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• 2016

Porosity in polymer matrix composites increases rapidly during thermochemical decomposition at high temperatures. The generation of pores reduces elastic moduli and failure strengths of composite materials, and gas pressures in internal pores influence thermomechanical behaviors. In this paper, micromechanical finite element analysis is carried out by using two-dimensional representative volume elements for unidirectionally fiber-reinforced composites with porous matrix. According to the state of the pores, effective elastic moduli, poroelastic parameters and failure strengths of the overall composites are investigated in detail. In particular, it is confirmed that the failure strengths in the transvers and through-thickness directions are predicted much more weakly than the strength of nonpored matrix, and decrease consistently as the porosity of matrix increases.

• 한국게임학회지
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• v.6 no.1
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• pp.44-47
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• 2009

분명한 것은 한국형 온라인게임의 특징적 원리들이 탑재되고 있는 방식과 현상은 점차 강화되고 있음에도 불구하고 게임사 주도적으로 전개되고 있는 산업의 성장모형은 평가기능으로 작동해야 할 조정 메커니즘의 원활한 흐름을 저해하는 길항관계에 있는 것은 사실이다. 이러한 문제를 인식하고 연구자는 게임연구의 활성화지점과 게임개발 테크놀로지가 가진 길항관계를 보완할 수 있는 디자인에 주목하고자 하였다. 게임디자인은 게임의 미적, 실용적, 경제적 가치를 창출하는 직무이면서 유관 콘텐츠산업과의 연계와 매개 가능성을 함의하고 있다는 측면에서 게임연구의 활성화지점의 매개로서 충분하다는 것이 연구자의 견해이다. 이 같은 주장의 전개를 위하여 국내에서 탄생한 온라인게임에 초점을 맞추고 국내 온라인게임의 전형이 되고 있는 핵 앤 슬래쉬(Hack & Slash) 방식과 허구적 공간에서의 게임화된 사회경험을 추구하는 스토리텔링 방식의 분석을 통해 국내형 온라인게임이 성취한 디자인 좌표를 검증하고, 이를 통해 국내 게임산업에 대두되고 있는 위기 스펙트럼과의 연관성은 어떤 것이며, 디자인은 어떠한 방향으로 매개되어야 할 것인지에 대한 의제로 접근하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.744-747
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• 2001

This paper shows shear wave behavior of CFRP composite laminates as a polar grid form to evaluate vibration pattern of ultrasonic transducers, which gives measured modelling fundamental contents of nondestructive evaluation. Polarized direction can be obtained by using a c-scanner and sensitivity of transducers is founded when using through-transmission method of two transducers. And modelling of vector decomposition is presented based on ply-to-ply method to apply practicable nondestructive evaluation of CFRP laminate lay up. This modelling decomposes the transmission of linearly polarized wave into orthogonal components through each ply of a laminate. It is found that a high provable shows between the model and experimental developed in characterizing layup of CFRP composite laminates.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.4 s.23
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• pp.136-145
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• 2005

특이응력해석을 위한 일반화된 가역상반일 경계적분식이 섬유강화복합재를 모형화한 직교 이방성 크랙평판의 수치해를 위하여 발전시켰다. 이 적분방정식은 평판경계에서의 탄성변위와 트랙션의 변수로 구성된 경계적분식의 형태로 하중이 없다는 두 크랙면의 경계조건과 유한의 탄성변형에너지의 개념에서 경계적분식에 필요한 특성해를 규정하고 대응되는 보조해를 계산하였다. 대칭모우드 I형의 중앙원공크랙평판 및 복합모우드형의 반원편측크랙 일단고정평판의 응력확대계수가 임의의 섬유방향각에 따라서 계산되었다.