• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.1055-1060
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• 2001

Springing phenomena of ships is introduced with its concept, research history and approach methodology. Being a hydroelasticity problem, non-linear vibration and stochastic process, springing was formulated and modeled in vibration point of view separating hydrodynamic force into system properties and excitation force. Both RAO and response spectrum as well as wave spectrum were presented as a case study of springing analysis for a flexible vessel with wide breadth. The effect of advance speed, heading angle and loading condition were investigated as parametric study. The results and observations showed availability of analysis for the prediction of the ship springing behavior.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(1)
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• pp.195-198
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• 2002

One-dimensional radar signature, such as range profile, is highly dependent on the aspect angle. Therefore, radar target recognition over wide angular region is a very difficult task. In this paper, we propose the Bayes classifier with Gaussian mixture model for radar target recognition over wide-angular region and compare performances of proposed technique and radar target recognition with subclasses concept in the literature of probability of correct classification ratio.

• 해양환경안전학회지
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• 제22권6호
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• pp.654-659
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• 2016

정기적으로 운행하던 여객선 세월호가 소각도 변침 중에 급격히 횡경사되면서 전복하는 사고가 최근 발생하였다. 선박의 횡경사가 발생 원인에 따라 Heel, List, Loll로 구분되어 그 원인에 따라 적절히 대응해야 함에도 불구하고 음의 복원력에 의한 횡경사(Loll)에 대한 항해사들의 인식이 매우 부족하다. 이에 본 연구에서는 음의 복원력에 의한 횡경사에 대한 개념, 발생과정 및 횡경사각 산정법을 고찰하고, 박스형 모형선을 이용한 수조 실험을 통해 실제 횡경사각의 발생과 음의 복원력 정도에 따른 횡경사각의 크기를 이론식과 비교 검증하였다. 그 결과, 실험값은 이론식에 의한 횡경사각 계산값과 잘 일치하였으며, 음의 복원력에 의한 횡경사의 특성으로서 좌현과 우현에서 동일한 각도의 횡경사가 발생하였다. 본 연구를 통하여 음의 복원력을 가진 선박의 거동에 관한 인식이 확대되고 과거 원인이 불명확한 전복사고의 원인분석에 참조되길 기대한다. 향후 음의 복원력에 의한 횡경사에서의 부적절한 대응으로 전개될 수 있는 선박의 거동에 관한 실험연구 및 사례연구가 필요하다고 사료된다.

• 대한치과교정학회지
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• 제27권2호
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• pp.245-258
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• 1997

본 연구에서는 대구에서 활동하고 있는 모델과 심미적인 안모를 가졌다고 추천받은 68명의 젊은 여성을 대상으로하여 두부X-선 사진, 정모 사진과 측모 실루엣 사진을 채득하였다. 두부X-선 사진의 연조직 측모선만을 사용한 3명씩의 측모 실루엣을 FH plane이 평행하게 한장에 그려서 제작한 사진을 경북대학교 미술학과 재학생 7명과 교정 전공의 15명에게 평가하게 하였으며 정모 사진은 교정 전공의만 평가하게 하였다. 아주 좋은 경우를 9점, 좋은 경우를 7점, 보통인 경우를 5점, 좋지 않은 경우를 3점으로 처리토록 하였다. 측모 실루엣에서 교정 전공의와 미대생의 심미안간의 상관관계, 교정 전공의가 평가한 정모와 측모의 심미성간의 상관관계, 교정 전공의가 평가한 측모 실루엣의 평균 점수가 5점 이상인 38명의 측모 계측항목과 측모 심미성간의 상관관계를 분석하여 다음과 같은 결론을 얻었다. 1. 측모 실루엣에서 교정 전공의와 미대생의 심미안간의 상관관계는 유의성있게 나타났다(r=0.67, P=0.0001). 2. 교정 전공의가 평가한 정모와 측모의 심미성간의 상관관계는 유의성있게 나타났다(r=0.26, P=0.0381). 3. 측모 실루엣과 상관관계가 유의성있게 나타난 항목은 Na-Pog to N', BNV to Pog', BNV/B'-Pog', Ls-Li-Pog', Li-B'-Pog', Z angle이었다(P<0.05). 4. 측모 계측항목의 평균치 및 표준편차를 구하였다.

• Journal of Biosystems Engineering
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• 제33권6호
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• pp.371-378
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• 2008

Bio-diesel applications seem to be extended due to bio-diesel policies and changes of agricultural environment. This study was conducted to develop a rapeseed reaping equipment attachable to the conventional combine. This paper was intended to report concept design, process and manufacturing of the prototype rapeseed reaping equipment. For concept design, physical properties of "SUNMANG", which is a typical rapeseed as bio-diesel materials, were considered. The designed prototype rapeseed reaping equipment consisted of wide-width plates, finger type knifes, side cutter knifes and drive equipments. The wide-width plate is 2.1 m wide, 0.7 m long, and 0.002 m thick. The finger type cutter knifes have 14.5 fingers, 30 knifes, and the specification was 7.6 cm of pitch, 8.3 cm of length and $21^{\circ}$ of cutting angle. The side cutter knifes consisted of a hydraulic pump, a hydraulic motor, a flow control and a relief valve, a hydraulic hose, a driving equipment and a reciprocating cutter knife. The 18 reciprocating cutter knifes were 137 cm long and knife pitch, knife length and cutting angle were 7.7 cm, 10.5 cm, and $18^{\circ}$. Prototype weight of the rapeseed reaping equipment was heavier by 272 kg when compared with the manual reaping equipments. Load distributions of left and right side showed 50% and 49%, and those of front and rear side showed 64% and 36%. Static turn-over angles in left and right of the prototype were $38.1^{\circ}$ and $38.7^{\circ}$, respectively. The designed prototype rapeseed reaping equipment was properly mounted at the front of a conventional combine.

• 콘크리트학회논문집
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• 제20권1호
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• pp.99-107
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• 2008

본 논문에서는 유효 스터럽 개념을 이용한 전단보강근의 강도 예측 방법을 제안하고 있다. 유효 스터럽 개념을 이용한 예측에서 가장 중요시 되는 부분인 전단 균열각 예측은 수정압축장이론 (modified compression field theory, MCFT)을 이용하여 수행하였다. 현 설계기준인 ACI 318-05와 기존 문헌에서 인용한 39개의 실제 실험 데이터를 이용하여 예측 방법의 유효성을 평가하였다. 평가시 고려한 영향인자로는 콘크리트 강도 그리고 전단보강근의 종류가 있었고, 추가로 2개의 full-scale의 보 실험을 수행하여 제안된 방법의 헤디드 바 사용 시험체의 확대 적용 가능성도 평가하였다.

• 한국인쇄학회지
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• 제25권1호
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• pp.43-52
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• 2007

Offset printing is one of the well known printing technique of lithographic process and consists of image area and 'non-image area on a flat image carrier. The surface tension of dampening water can be controlled by adding IPA after mixing of raw water and etching solution. The etching solution contains a surfactant for reducing surface energy, a clean agent for non-imaging area, wetting agent for protecting non-imaging area from oil components like ink and also an emulsifying agent for controlling emulsification. In this study, the present situation of dampening water maintenance has examined by collecting dampening water using at domestic companies. The pH related to dampening water, conductivity, contact angle, emulsification curve are measured to define the current situation of dampening water control of each companies and to analyze the relationship among measured properties. In the study most of companies among 16 printing companies tested controlling dampening water through pH value. However, the quality of printing has varied depending upon conductivity, contact angle, IPA content, and emulsification value. The control of dampening water should be carry at the state of the standard when adding proper ratio of etching solution. It would be more effective when pH or conductivity control carries out in parallel with controlling dampening water. Therefore the concept that pH5.5 is correct is based concept. Based on these initial tests it is defined that the standardization of dampening water control is required.

• 한국가스학회지
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• 제13권2호
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• pp.30-35
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• 2009

본 연구는 지중에서 배관이 교차할 때 상부 강성관이 하부 연성관에 영향을 미치는 유효 깊이와 유효 길이에 대한 개념을 이용하여 두 매설 배관의 교차 정도와 배관 사이의 거리에 따른 하부 매설 배관의 영향범위를 파악 하고자한다. 이를 위하여 상부 배관과 하부 배관을 각각 원심력 철근콘크리트관과 가스수송용 강관으로 구현하였다. 이때 1.0m에 매설된 상부 배관으로부터 하부 배관은 각각 0.5m에서 5m의 매설심도를 가지며 두 배관의 교차각을 0, 30, 60, $90^{\circ}$로 변화하여 연구를 진행하였다. 그 결과 유효깊이는 두 매설 배관의 교차각이 증가함에 따라 증가하며, 두 매설관 사이의 거리가 증가함에 따라 감소하다 일정 값으로 수렴하게 된다. 또한 두 교차 배관의 교차 각 증가에 따른 유효길이와 휨응력 합의 관계를 정리하였다.

• Geomechanics and Engineering
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• 제14권1호
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• pp.29-42
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• 2018

This paper presents the results of an empirical study in which square rock-like blocks containing two parallel pre-existing rough non-persistent joints were subjected to uniaxial compression load. The main purpose of this study was to investigate uniaxial compressive strength and deformation modulus of jointed specimens. Response Surface Method (RSM) was utilized to design experiments and investigate the effect of four joint parameters, namely joint roughness coefficient (JRC), bridge length (L), bridge angle (${\gamma}$), and joint inclination (${\theta}$). The interaction of these parameters on the uniaxial compressive strength (UCS) and deformation modulus of the blocks was investigated as well. The results indicated that an increase in joint roughness coefficient, bridge length and bridge angle increased compressive strength and deformation modulus. Moreover, increasing joint inclination decreased the two mechanical properties. The concept of 'interlocking cracks' which are mixed mode (shear-tensile cracks) was introduced. This type of cracks can happen in higher level of JRC. Initiation and propagation of this type of cracks reduces mechanical properties of sample before reaching its peak strength. The results of the Response Surface Methodology showed that the mutual interaction of the joint parameters had a significant influence on the compressive strength and deformation modulus.

• Steel and Composite Structures
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• 제49권2호
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• pp.125-141
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• 2023

Firstly, a new kind of prismatic tensegrity structures with redundant cables is defined, the topology, geometry and forming conditions of which are introduced further. The development of its mechanical properties including self-stress states and structural stiffness with the increment of the twist angle is also investigated carefully. Combined with the topology of this kind of structures, a reasonable erection scheme is proposed, in which some temporary lifting points need to be set and two groups of vertical cables are tensioned in batches. Then, a simplified dynamic relaxation method is employed to track the erection process inversely, which aims to predict each intermediate equilibrium state during the construction, and give the key structural parameters that can effectively guide the construction. The removal of the active cables, the relaxation or tension of the passive cables are simulated by controlling their axial stiffness, so that the structural composition as well as the serial numbers of the elements always keep invariant regardless of the withdrawal of the slack cables. The whole analysis process is clear in concept, simple to implement and easy to popularize. Finally, several examples are given to verify the practicability and effectiveness of the proposed method further.