• Geomechanics and Engineering
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• 제36권3호
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• pp.295-301
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• 2024

Understanding the post-liquefaction shear behavior is crucial for predicting and assessing the damage, such as lateral flow, caused by liquefaction. Most studies have focused on the behavior until liquefaction occurs. In this study, we performed undrained multi-stage tests on clean sand, sand-silt mixtures, and silty soils to investigate post-liquefaction shear strain based on soil compressibility. The results confirmed that it is necessary to consider the soil compressibility and the shape of soil particles to understand the post-liquefaction shear strain characteristics. Based on this, an index reflecting soil compressibility and particle shape was derived, and the results showed a high correlation with post-liquefaction small resistance characteristic regardless of soil type and fine particle content.

• 한국자동차공학회논문집
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• 제17권2호
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• pp.49-56
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• 2009

In this study, a side collision accident reconstruction using database based on the deformed shape information from the collision test using model cars is suggested. A deformation index and angle index related to the deformed shape is developed to set the database for the collision accident reconstruction algorithm. Two small size RC cars are developed to carry out the side collision test. Several side collision tests according to the velocity and collision angles are performed for establishing the side collision database. A high speed camera with 1000fps is used to capture the motion of the car. A side collision accident reconstruction algorithm is developed and applied to find the collision conditions before the accident occurs. Two collision cases are tested to validate the database and the algorithm. The results obtained by the reconstruction algorithm show good match with original conditions with regard to the velocity and angle.

• 대한전자공학회논문지
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• 제24권4호
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• pp.696-700
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• 1987

Guide modes in a graded index multinmode optical fiber are turned into clad modes when the optical fiber was bended into a perpendicular direction to its optical axes by microbending forces, which causes the loss of the guiding optical power. The theories reported on this microbending power loss can be applied to calculation of the transmission power loss only when the beding period equals to the mode coupling length. In this paper, we obtained the general expression of the optical power transmission loss in a graded index multimode fiber bended periodically. This can be applied to the calculation of the power loss of the periodically microbended fiber with an arbitrary bending shape and period. Also, by using the beam theory in mechanics, we could derive the expression of the displacement of the optical fiber caused by the external force which bends the fiber into a periodic trapezoidal shape. Experiments were carried out to determine the dependence of the power loss on the period of the microbending forces. Experimnetal results were in good agreement (in the same order of the magnitude) with theoritical values derived in our work within the bending period region of 2mm-10mm.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.106-109
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• 2002

With the wide application of fiber-reinforced composite material in aero-structures and mechanical parts, the design of composite joint have become a very important research area because they are often the weakest areas in composite structures. In this paper, the failure area index method to predict the strength of the mechanically fastened composite joint which has the same stacking sequence was used and evaluated. By the used failure area index method, the strength of the mechanically fastened composite joint which has the specimen of different shape and stacking sequence could be predicted within 9.96%.

• Steel and Composite Structures
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• 제36권1호
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• pp.31-45
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• 2020

The purpose of this study is to develop an effective iterative two-stage method (ITSM) for structural damage identification of offshore platform structures. In each iteration, a new damage index, Modal Energy-Based Damage Index (MEBI), is proposed to help effectively locate the potential damage elements in the first stage. Then, in the second stage, the beetle antenna search (BAS) algorithm is used to estimate the damage severity of these elements. Compared with the well-known particle swarm optimization (PSO) algorithm and genetic algorithm (GA), this algorithm has lower computational cost. A modal energy based objective function for the optimization process is proposed. Using numerical and experimental data, the efficiency and accuracy of the ITSM are studied. The effects of measurement noise and spatial incompleteness of mode shape are both considered. All the obtained results show that under these influences, the ITSM can accurately identify the true location and severity of damage. The results also show that the objective function based on modal energy is most suitable for the ITSM compared with that based on flexibility and weighted natural frequency-mode shape.

• 상하수도학회지
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• 제22권1호
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• pp.105-112
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• 2008

Disinfection is a basic and effective microorganism inactivation method and historically contributed a decrease in waterborne diseases. To guarantee the disinfection ability, improving T in CT value is important. Many indexes are used to estimate the hydraulic efficiency, however, these are black-box analysis. Therefore it is need to develope new estimation method. In this study, internal short-circuiting estimation method (ISEM) is developed using CFD and we inquire into the factor which causes increase of $T_{10}/T$ value as LW ratio increases. And the effect of shape on the relation of LW ratio and $T_{10}/T$ is analyzed. As LW ratio increases, internal short-circuiting index (ISI) of influent and effluent zone is rapidly reduced and recirculation and dead zone are reduced in channel zone. Therefore, as the $T_{10}/T$ value converges maximum value, ISI curve is changed from "V" shape to "U" shape and hydraulic efficiency is improved especially in downstream portion of clearwell. The less the shape ratio(width/length of clearwell) is the less the $T_{10}/T$ value is at a same LW ratio because the portion of turning zone increases as shape ration decreases, therefore more boundary separation is generated.

• 한국콘텐츠학회논문지
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• 제15권10호
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• pp.327-335
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• 2015

본 연구는 후기청소년의 자신의 체형에 대한 인식, 대인관계 문제, 그리고 영적 안녕의 정도를 확인하고 그 관계를 규명하기 위한 목적으로 시행된 서술적 조사연구이다. 본 연구 대상자는 수도권 소재 1개 고등학교 3학년 학생과 2개 대학교의 학생으로 본 연구에 참여하기로 동의한 116명을 임의로 표출하였다. 2012년 10월 12일부터 11월 16일까지 구조화된 질문지를 이용하여 진행되었으며, 수집된 자료는 t-test, Kruskal-Wallis test, Bonferroni correction, Pearson's correlation coefficient 등을 통해 분석되었다. 연구 결과는 다음과 같다. 연구대상자의 94.9%가 체질량지수가 저체중 혹은 정상체중이었지만 현재 보다 더 마르기를 원하는 것으로 나타났다. 체형 인식은 성별, 종교 유무, 체중조절 경험 유무, 현재 체질량지수와 원하는 체질량 지수에서 그룹 간 유의한 차이가 있었고, 영적 안녕은 종교 유무와 음주경험에 따라 유의한 차이가 있었다. 체형 인식과 대인관계 문제는 통계적으로 유의한 상관관계가 없었으며, 대인관계 문제와 영적 안녕 간에는 유의한 음의 상관관계가 나타났다. 본 연구 결과를 통해 후기 청소년의 왜곡된 체형 인식에 대한 교육과 상담의 필요성이 있으며, 후기 청소년의 대인관계 문제에 대한 중재 요소로서 영적 안녕에 대한 영역을 활용하기를 기대한다.

• 한국의류산업학회지
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• 제22권4호
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• pp.495-503
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• 2020

This study classified lower body shape according to thigh and waist shape to improve the fit of skinny blue jeans in adult women in their 20s. We analyzed the three-dimensional automatic measurement data, three-dimensional indirect measurement data, and index data using the three-dimensional female (20-29 years old) body scan data provided by Size Korea (6^th Korean Human Dimensional Survey Project). Factor analysis was performed to classify body type. We selected and analyzed 34 items related to thigh shape based on index items, angle items, and protrusion amount items from 99 items; consequently, seven factors were extracted and 82.39% of the total variance was explained. Cluster analysis according to factor analysis classified it into 4 types, and a post-test Duncan test was conducted to classify thigh features according to classified types. As a result, the characteristics of lower body shape according to the thigh types of women in their 20s are as follows. Lower Body Type 1 is shape with a more prominent belly and less prominent thighs. Lower Body Type 2 is a slender body figure with larger hips. Lower Body Type 3 has more prominent thighs compared to the waist and belly. Lower Body Type 4 has both a prominent belly and prominent thighs.

• 치위생과학회지
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• 제23권3호
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• pp.193-198
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• 2023

Background: The nose is located at the center of the face, and it is possible to determine race, sex, and the like. Research using the nasal index (NI) classification method to classify the shape of the nose is currently in progress. However, domestic research is required as most research is being conducted abroad. In this study, we used a 3D program to confirm the ratio of the nose shape of Koreans. Methods: One hundred patients (50 males and 50 females) in their 20s were evaluated (IRB approval no. DKUDH IRB 2020-01-007). Cone beam computed tomography was performed using the Mimics ver.22 (Materialise Co., Leuven, Belgium) 3D program to model the patient's skull and soft tissues into three views: coronal, sagittal, and frontal. To confirm the ratio of measurement metrics, analysis was performed using the SPSS ver. 23.0 (IBM Co., Armonk, NY, USA) program. Results: Ten leptorrhine (long and narrow) type, 76 mesorrhine (moderate shape) type, and 14 platyrrhine (broad and short) type noses were observed. In addition, as a result of sex comparison, five males had the leptorrhine (long and narrow) type, 40 mesorrhine (moderate shape), and five platyrrhine (broad and short) types. For females, five patients had the leptorrhine (long and narrow) type, 36 patients had the mesorrhine (moderate shape) type, and nine patients had the platyrrhine (broad and short) type. Conclusion: This study will be helpful when performing nose-related surgeries and procedures in clinical practice and for similar studies in the future.

• 복식
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• 제47권
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• pp.73-88
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• 1999

To find the reasonable gathering amount by a length of gathered skirt and a fabric the methods of this study were divided on three types-five kinds of the gathering amounts three kinds of fabrics and three kinds of skirt length-so forty five kinds of the samples were made. As the visual evaluation and the shape of hemlines evaluation of the gathered skirt were practiced by these factors this study found the aesthetical gathering amount and analyzed the shape of hemlines. The following are the results of this research. 1. In the same fabric and skirt length to estimate a hemlines shape of a gathered skirt the increased amount of the node number of cotton fabric was widest and wool fabric was most stable And when the gathering amounts of each fabric were higher than 1.5 times the node indexes were no difference. According as a skirt length was longer the node indexes assumed a similar aspects but according as the skirt length was shorten an the gathering amount was smaller the node shapes were level and broad. And according to being increased a gathering amount the width of right and left of gathered skirt was generally wider. 2. In the same gathering amount and skirt length in seeing the estimation of a hemlines shape of a gathered skirt when the skirt length was 40cm in cotton polyester wool fabrics the node indexes were similar at up to 1.5 times of gathering amount and especially it became very bigger at 0.5 times and according as the gathering amount was increased node index became gradually smaller. The width of right and left of the skirt hemlines of wool fabric was more smaller than polyester and cotton fabrics so it is happen to hang down. 3. In the same gathering amount and fabric in seeing the estimation of a hemlines shape as a variation of a skirt length when the gathering amount of cotton and polyester was from up to 1.5 times and wood fabric was from up to 1.0 times according as skirt length was longer node index in the same gathering amount was decreased. And in case as it was 0.5 times the node indexes of the 40cm and 60cm skirt length were bigger than other factors. In the same gathering amount the width of right and left of the skirt hemlines was smaller at 60cm skirt length and polyester fabric was smaller at 80cm skirt length.