• Journal of Korea Society of Industrial Information Systems
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• v.7 no.4
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• pp.83-89
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• 2002

Oil ring and sound proof rubbers are very much important because the cause of oil leakage are mostly occupied by these rubbers. So good oil rings are the necessary parts of autolife expansion. The expensive selection system keeps from factory automation and most works are established manually. These study has been the basis of test equipments automatically in rubber products and DCT algorithm has been applied and the selection system is made efficiently differentiating good or poor.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.113-115
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• 2022

치과 진료는 대부분 인간의 시각에 의존하여 진단과 진료가 이루어진다. 하지만 미세한 치아 손상의 경우 의사가 육안으로 확인하기 어려울 수 있으며, 의사의 실력 및 피로 누적에 의해 조기에 발견을 하지 못할 가능성이 높아진다. 만약 미세한 치아 손상을 조기에 발견하지 못할 경우 시간이 지남에 따라 손상 부위가 커지고, 이를 치료하기 위해 더 큰 비용과 고통이 따르기 때문에 치과에서의 조기 발견이 매우 중요하다. 한편, 인류는 디지털 헬스케어 기술을 개발하여 보다 정확한 진단을 할 수 있게 되었고, 의료 서비스를 효율적으로 제공할 수 있게 되었다. 이에 본 논문에서는 위의 문제를 해결하기 위해 디지털 헬스케어를 사용하여 빅데이터와 딥러닝을 활용한 지능형 전자 루페에 대해 탐구하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.147-147
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• 2022

본 연구의 목적은 소형 어선에서 항해사로 인해 발생하는 인적오류에 의해서 야기될 수 있는 선박 충돌사고를 예방하여 항행안전을 도모함에 있다. 이를 위해 2005년부터 2020년까지 총 16년의 해양사고재결서를 수집하여 주제어, 사고 관련 법규, 사고위치, 사고일시 등 사고 관련 내용을 분류하였다. 분류한 내용을 기반으로 원인판단 주제어와 사고 요인들과의 상관관계를 분석하였다. 그 결과 경계소흘은 충돌 원인의 대부분을 차지하였고, 경계소홀의 원인은 무리한 조업으로 인한 피로 누적과 졸음이 상당수를 차지하였다. 이는 소형 어선의 선박 충돌사고를 예방하기 위해서는 경계소흘에 대한 대응방안이 필요하다는 것이고, 기술 개발에 따른 자동화 등의 방법을 통해 소형 선박 충돌사고 예방 연구가 적용되어야 한다. 추후에는 소형 어선의 작업 특성을 분석하겠으며, 실제 충돌사고 예방에 기여할 수 있는 연구를 수행할 예정이다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.137-140
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• 2008

현대 사회는 육체적·정신적 활동을 많이 요구하게 되며 이러한 현상으로 스트레스의 증가와 이유없는 증후군의 발병이 점차 확대되고 있다. 특히 스트레스로 인한 피로의 누적으로 인체의 혈액 농도 및 순환에 영향을 끼치게 되며 이로 인해 신장의 상태가 악화될 수 있다. 따라서 신장의 이상 유무를 조기에 판단하여 적절한 조치를 취하는 것이 무엇보다 중요하다. 이를 위해 본 논문에서는 신장 질환을 앓고 있는 환자와 정상인을 대상으로 피실험자 집단군을 각각 구성하고 음성 정보의 형태학적 분석과 수치학적 분석을 실험으로 출력하고 결과값에 대해 비교·분석을 행하고자 한다. 최종적으로 실험을 통해 신장과 음성과의 관계를 정립하고자 한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.4
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• pp.537-548
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• 2022

It is important to design the pavement thickness considering heavy-duty traffic loads, which can cause excessive stress and strain in the pavement. Port-rear roads and industrial roads have many problems due to early stress in pavement because these have a higher ratio of heavy loads than general roads such as national roads and expressways. Internationally, composite pavement has been widely applied in pavement designs in heavy-duty areas. Composite pavement is established as an economic pavement type that can increase the design life by nearly double compared to that of existing pavement while also decreasing maintenance and user costs. This study suggests a thickness design method for composite pavement using roller-compacted concrete as a base material to ensure long-term serviceability in heavy-duty areas such as port-rear roads and industrial roads. A three-dimensional finite element analysis was conducted to investigate the mechanical behavior and the long-term pavement performance ultimately to suggest a thickness design method that considers changes in the material properties of the roller-compacted concrete (RCC) base layer. In addition, this study presents a user-friendly catalog design method for RCC-base composite pavement considering the concept of linear damage accumulation for each container trailer depending on the season.

• Journal of the Korean GEO-environmental Society
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• v.11 no.12
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• pp.5-11
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• 2010

If the groundwater in rock joint is changed into ice, it induces the stress increment by volume increase. Also, if the ice is changed into groundwater again, the stress in joint decreases by volume decrease. The accumulated displacement and fatigues of joints are increased by the stress-hysterisis, induced from the continuous frost-thawing. Also the shear strength is decreased by them continuously. The stress-hysterisis is affected by the atmospheric temperature changes, whose behavior is visco-elasticity, usually. Therefore, Kelvin model could be used to analyze the frost-thawing behavior in winter. The measured data of total 5 points are examined, which are composed of 3 points of shallow joints and 2 points of deep joints. Because shallow weathered rocks have many joints, a lot of Kelvin model are connected and the behaviors are complicated. In case of deep joints, simple Kelvin model is applied and the behaviors are also simple.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.4
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• pp.1-13
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• 2018

Purpose : The purpose of this study has been performed to find the relationship between seafarers' cumulative fatigue and stress by evaluating autonomic nervous functions and the results of surveys conducted using questionnaires. Methods : The subjects were seafarers working on various ships (home trade ships) of South Korea, who were healthy adults without any diseases, as confirmed through preliminary surveys were recruited through simple random sampling. A device that measures autonomic nervous functions by analyzing heart rate variability, which is also used often in clinical diagnoses and studies at universities, university hospitals, and general hospitals was used to measure the seafarers' cumulative fatigue and stress. Pearson's correlation analyses were also conducted to test the relationship between cumulative fatigue and stress measured by evaluating autonomic nervous functions and the results of surveys conducted with questionnaires. Results : There was no correlation between mean cumulative fatigue measured for each ship type and seafarers position through autonomic nervous functions evaluation and fatigue severity scale (FSS). There also was no correlation between the mean levels of stress measured for each ship type and seafarers position through autonomic nervous functions evaluation and survey scores of Korean occupational stress scale (KOSS). Conclusion : Therefore, in order to prevent man-made accidents in the sea among seafarers working with irregular port entry/departure schedules and under environments involving continued vibration, noises, and shaking, it is necessary to analyzed cumulative fatigue and stress scientifically and objectively, such as through autonomic nervous functions evaluation rather than through surveys.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.5
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• pp.399-405
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• 2010

The accumulated displacements and fatigues of rock are increased by the stress-hysteresis, induced from repeated frost-thawing. Also the shear strength is decreased by them continuously. The stress-hysteresis is affected by the atmospheric temperature changes, whose behavior is visco-elasticity, usually. Therefore, to do ideal body analysis, Kelvin model could be used to analyze the frost-thawing behavior in winter. In general, rock slope failure occurs by the deterioration of rocks, which is caused by the repetition of freezing-thawing process. In order to keep the safety of such rock mass structures the deterioration process of rock needs to be described quantitatively using some meaningful parameters. In this work, the deterioration process in freezing-thawing cycle of tuff, which is a famous soft porous rock, is investigated through laboratory tests and successfully described as a differential equation for the change of porosity. And then, the deterioration of the mechanical properties of rock, such as Young's modulus and uniaxial compressive strength, are quantitatively described as a function of the porosity.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.3
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• pp.579-587
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• 1998

In this study, fatigue behavior of the optical fiber sensor embedded in composite laminate was investigated. Static tensile and fatigue tests were performed for three types of laminated composite specimens with embedded optical fiber sensor in the neutral plane ; [0/sub 6//OF/0/sub 6/]/sub T/, [0/sub 2//90/sub 4//OF/90/sub 4//0/sub 2/]/sub T/ and [0/sub 3//90/sub 3//OF/90/sub 3//0/sub 3/]/sub T/. The fracture of the embedded optical fiber sensor was detected by the intensity drop off of laser signal transmitted through the optical fiber sensors embedded within laminated composite specimen. The maximum fatigue stress applied to laminated specimen was compared with the average tensile stress at which the fracture of the embedded optical fiber within the laminate occurred under static tensile loading. From the experiments, firstly it is observed that the decrease in the life of optical fiber sensors embedded within unidirectional-ply laminate by the fatigue loading is relatively small compared to that of cross-ply laminate. Secondly, the optical fiber embedded in unidirectional-ply laminate is fractured by the fatigue damage due to the growth of internal defects of optical fiber, however the optical fiber embedded in cross-ply laminate is fractured by the growth of transverse matrix crack.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.10
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• pp.77-83
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• 2008

In terms of saving costs, energy and materials, the weight of cars has been gradually reduced by optimizing design of structure, which also gives us good performance. In compliance with this, it should satisfy the lifetime of cars for 25 years under the operation. The purpose of this study is to evaluate the strength of fatigue using date from strain gauges attached carbody and bogie frame. This dynamic stress can be evaluated using S-N curve based on stress amplitude. Modified S-N curve by CORTON-DOLAN is used for more conservative and substantial evaluation. In addition, !he loadings itself of carbody and bogie frame are considered by calculating the rate of the differences which are occurred between empty car and fuiiy occupied car with passengers. Rainflow cycle counting method is applied to arrange the stress data for the modified S-N curve to predict lifetime of the materials. Conclusively the cumulative damages are not only calculated by Miner's Rule, but the safety factors are also determined by Goodman diagram.