• Geomechanics and Engineering
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• 제38권6호
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• pp.633-645
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• 2024

Disc cutters, used as excavation tools for rocks in a Tunnel Boring Machine (TBM), naturally undergo wear during the tunneling process, involving crushing and cutting through the ground, leading to various wear types. When disc cutters reach their wear limits, they must be replaced at the appropriate time to ensure efficient excavation. General disc cutter life prediction models are typically used during the design phase to predict the total required quantity and replacement locations for construction. However, disc cutters are replaced more frequently during tunneling than initially planned. Unpredictable disc cutter replacements can easily diminish tunneling efficiency, and abnormal wear is a common cause during tunneling in complex ground conditions. This study aims to overcome the limitations of existing disc cutter life prediction models by utilizing machine data generated during tunneling to predict disc cutter wear patterns and determine the need for replacements in real-time. Artificial intelligence classification algorithms, including K-nearest Neighbors (KNN), Support Vector Machine (SVM), Decision Tree (DT), and Stacking, are employed to assess the need for disc cutter replacement. Binary classification models are developed to predict which disc cutters require replacement, while multi-class classification models are fine-tuned to identify three categories: no replacement required, replacement due to normal wear, and replacement due to abnormal wear during tunneling. The performance of these models is thoroughly assessed, demonstrating that the proposed approach effectively manages disc cutter wear and replacements in shield TBM tunnel projects.

• Journal of Preventive Medicine and Public Health
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• 제49권5호
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• pp.301-307
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• 2016

Objectives: This study investigated the association between perceived ethnic discrimination and depressive symptoms among biethnic adolescents in South Korea. Methods: We performed a cross-sectional study of 4141 biethnic adolescents using data from the 2012 National Survey of Multicultural Families. Perceived ethnic discrimination was measured using the question "Have you ever been discriminated against or ignored because either of your parents is not a Korean?" with an assessment of depressive symptoms over the past 12 months. Logistic regression was applied to examine potential associations between perceived ethnic discrimination and depressive symptoms. Results: Among 4141 biethnic adolescents, 558 (13.5%) reported having experienced ethnic discrimination. The most common discriminatory perpetrators were friends (n=241, 5.8%), followed by strangers (n=67, 1.6%). Depressive symptoms were related to experience of ethnic discrimination (odds ratio [OR], 3.80; 95% confidence interval [CI], 2.89 to 4.98) after adjusting for potential confounders. In an analysis focusing on the perpetrators of discrimination, depressive symptoms were found to be associated with perceived ethnic discrimination from friends (OR, 3.95; 95% CI, 2.75 to 5.68), teachers (OR, 4.53; 95% CI, 2.16 to 9.51), family members and relatives (OR, 3.89; 95% CI, 1.59 to 9.48), neighbors (OR, 2.48; 95% CI, 1.14 to 5.38), and strangers (OR, 2.49; 95% CI, 1.30 to 4.79). Furthermore, the OR for depressive symptoms among those exposed to 1, 2, or 3 or more discriminatory perpetrators were 3.61 (95% CI, 2.49 to 5.24), 3.61 (95% CI, 1.68 to 7.74), and 6.69 (95% CI, 2.94 to 15.22), respectively. Conclusions: According to our findings, friends were the most common perpetrators of discrimination and the experience of ethnic discrimination was associated with depressive symptoms among biethnic adolescents in South Korea.

• 디지털콘텐츠학회 논문지
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• 제18권4호
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• pp.739-745
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• 2017

본 논문에서는 GPU 병렬 처리 하드웨어 아키텍처 내 최소 물리적 스레드 실행 단위(warp) 내에서 shifted sort 기반 k개 최근접 이웃 검색 기법을 구현하는 방법을 논의하고 일반적으로 동일한 목적으로 널리 사용되는 GPU 기반 kd-tree 및 CPU 기반 ANN 라이브러리와 비교한 결과를 제시한다. 또한 많은 애플리케이션에서 k가 비교적 작은 값이 필요한 경우가 많다는 사실을 고려해서 k가 warp 내부에서 직접 처리 가능한 2, 4, 8, 16개일 때 최적화에 집중한다. 구현 세부에서는 사용한 CUB 공개 라이브러리의 루프 내 메모리 관리 방법, GPU 하드웨어 직접 명령 적용 방법 등의 최적화 방법을 논의한다. 실험 결과, 제안하는 방법은 기존의 GPU 기반 유사 방법에 비해 데이터 지점과 질의 지점의 개수가 각각 $2^{23}$개 일 때 16배 이상의 빠른 처리 속도를 보였으며 이러한 경향은 처리해야 할 데이터의 크기가 커지면 더욱 더 커지는 것으로 판단된다.

• 한국컴퓨터정보학회논문지
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• 제26권11호
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• pp.149-156
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• 2021

추천 시스템의 여러 구현 기법들 중 협력 필터링은 과거 평가 이력을 토대로 유사성이 높은 인접 이웃들을 선정하여, 그들이 선호했던 상품들을 추천하는데, 많은 상업 사이트에서 성공적으로 활용되고 있다. 유사도의 정확한 측정은 시스템의 성능을 좌우하는 매우 중요한 요소이다. 기존에 다양한 방식의 유사도 척도들이 개발되었는데, 대개 전통적인 유사도 척도와 기개발된 여러 계수들과의 통합 방식이었다. 본 연구에서는 새로운 방식의 유사도 척도를 제안한다. 두 사용자 간의 공통 평가 영역을 평가치 크기에 따라 분할하여 각 부분 영역별로 유사도를 측정하고 이들을 가중 통합함으로써, 유사한 영역이 구체적으로 파악되어 최종 유사도값에 반영된다. 두 종류의 개방형 데이터셋을 활용한 성능을 측정하였고, 그 결과 특히 밀집 데이터셋에서 제안 방법의 예측 정확도, 순위 정확도, 평균 정밀도 성능이 기존보다 우수하였다. 제안 척도는 다양한 상업 시스템에서 사용자들의 선호에 보다 적합한 상품을 추천하는데 유용하게 활용될 것으로 기대한다.

• 대한건축학회논문집:계획계
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• 제35권1호
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• pp.55-62
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• 2019

Hayakawa Kunihiko introduced community space as an open space in Housing in Japan for the first time. We can find the continuity of his architectural intent from his three works (Atrium, Steps, Labyrinth) during the early period of his Housing buildings, In particular, from Labyrinth, his intent was expanded to cities through 'Urban Void', seeking communication and harmony. Accordingly, based on the architectural overview and a field survey of Labyrinth, an analysis was conducted using Space Syntax to investigate whether the space of an inner courtyard is being used as a community space for neighbors who pass through the courtyard and whether the courtyard plays the role of 'Urban Void' as intended by the architect. For this investigation, according to VGA, the courtyard showed the role of great visual connectivity and integration and facilitated connections to the center of the entire space. On the other hand, according to J-Graph, the access stairway connected to each household from the courtyard helped secure privacy in the midst of common space. Step Depth noted that a hierarchy of space was formed to ensure visual privacy within each unit household in addition to privacy for each household.

• 대한건축학회논문집:계획계
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• 제36권2호
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• pp.13-24
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• 2020

This study derives the characteristics of the private external space planning in multi-family housing through the analysis of the good case built after 2000 in Europe. First, the cases were categorized into block or block perimeter, linear and point type to examine the relationship between the type of building in urban context and the location of private external space. By block or block perimeter and linear type, private external spaces are planned in the inner courtyards or open space between buildings used as common space for residents, inducing communications between neighbors. And the direction of private external space depends on the arrangement of the building mass in urban context. In the classification as point type, there are many cases, where private external spaces are arranged in all directions, connected almost all interior spaces. Second, based on the above results, the planned characteristics of the private external space are derived by dividing it into three categories: intermediated space between inside and outside, intermediate space between private and public /individual and collective space and the identity of the intermediate space. (1) In most cases, direction, size of enclosed area and location of private extern space is designed to fit the surrounding context, so residents can perceive as much of the assets of the surrounding environment as possible, and it can be used as an extended area of living space. In another cases, it is divided into various sub-areas to experience the spatial transition from inside to outside or vice versa. 2) The private external space, which is placed in a courtyard or in a collective open space, is partially enclosed and blocked, allowing interaction with the neighbors without pressure. Along the street, they are designed to allow residents to experience the vitality of the city and to be formative element of the facade, which could confidently reveal the lifestyle and taste of residents. 3) By some of point types, which facade is three-demensional layer as a habitable external space, the private external space is very flexible for use. This intermediate space is composed of diverse spaces for various needs, or it has generous size with positional conditions connected with all interior spaces to be used multi-functional.

• 한국가족관계학회지
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• 제21권2호
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• pp.25-51
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• 2016

Objectives: This research started with the attempt to comprehend the relationship between household types and psychological stability by linking single-person households to the emotional index "depression." Method: For this purpose, we first compare to see if there is a difference in socio-demographic variables, social relationships, the degree of depression between single households and multi-person households, and to comprehend the relative influence that household types have on depression by taking other factors under consideration. Results: Then based on the results, we compare and analyze the factors that affect the degree of depression on single-person households and multi-person households, respectively. To summarize the results, first of all, residents in single-person households are somewhat older but show lower level of income, education, and health condition compared to peers inmulti-person households. They also had a consistently high level not only in the frequency of contact and emotional connection with families, relatives, and friends, but also in the degree of depression when compared to multi-person households. Secondly, for depression, considering the various factors targeting all the households, the following had a strong influence in the order of "health condition compared to peers," "emotional connection with family," "household types," "emotional connection with colleagues," "frequency of contact with neighbors," "gender," and "age."The degree of depression increases in the following conditions: if the health condition is worse, lower emotional connection with family, single-person household, lower emotional connection with colleagues, lower the frequency of contact with neighbors, female, and older the age. Thirdly, comparing the factors that affect depression by dividing single-person households and multi-person households, "health condition compared to peers" and "emotional connection with family" had the largest effect in common, respectively. In cases of living alone, regardless of other factors, the degree of depression increases with "health condition compared to peers" and "emotional connection with family." Conclusions: On the contrary, in multi-person households, "health condition compared to peers," "emotional connection with family," "emotional connection with colleagues," "income," and "gender" are important.

• 한국실내디자인학회논문집
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• 제22권3호
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• pp.22-32
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• 2013

The quality of apartment houses has been gradually upgraded. However the changes in demographic composition of residents such as seniors, disabled persons, and etc. have not been considered in the process of planning. If apartment houses are designed on the base of the concept of universal design, their residents could live as long as they want to live in. This study evaluates the Korean standard-sized apartment housing units and the common spaces of those apartment buildings, and it's outdoor environments from the perspective of universal design. The observation and measuring was conducted with the questionnaire survey with 100 residents living in those housing units. 60 items were designed for evaluating them in relation to the principles of universal design. The results are as follows : 1) In general, the principles of universal design were relatively applied to the apartment houses. However their application needs to be broadened. 2) The number of parking lots needs to be increased and the width of individual parking lot to be increased. Also, the location of gazebo and senior center needs to be placed in easily accessible areas. 3) The shape, color, finishes of the ramp and the entrance area of the apartment building and housing unit should be made more homelike. Also, the entrance area of apartment building and housing unit needs to be made large enough for residents themselves and meeting with neighbors. 4) Among all of the rooms in a housing unit, bathroom should be improved immediately. Also, the width of doors should be at least 80cm wide and the floor should be made even.

• 한국소음진동공학회논문집
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• 제24권4호
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• pp.339-347
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• 2014

Floor impact sound in high-rise apartment building became one of social problems. A lot of civil complaints on floor impact sound occur continuously and the number of disputes between neighbors in small and aged apartment buildings is increasing. Interests on heavy-weight impact sound pressure level measurement and evaluation method is increased. Previous study reported that heavy-weight impact sound level was changed by the sound field condition of receiving reverberation chamber. In this study, heavy-weight impact sound pressure level change by the receiving sound field condition was measured in standard test facility and mock-up test room. These two experimental conditions were designed to simulate averaged living room of common apartment units. By the change of sound absorption power in receiving room, heavy-weight impact sound pressure level in most of frequency bands were changed in standard test facility and mock-up room. Normalized maximum sound pressure level regulated in ISO 16032 showed wider range of heavy/soft impact sound pressure level. Heavy/soft impact sound pressure level change was became smaller by the application of standardized maximum sound pressure level and ISO/CD 10140-3 Amd 2 method. In the case of standardized maximum sound pressure level, absolute sound pressure level changed. From these results, receiving sound field correction method regulated in ISO/CD 10140-3 Amd 2 is needed for the precision measurement and evaluation of heavy-weight impact sound.

• 한국정보과학회논문지:정보통신
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• 제37권4호
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• pp.301-306
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• 2010

이 논문은 클러스터 형태의 다중 인터페이스 다중 홉 인지 라디오 환경을 위한 효율적인 제어 채널 접근 방식을 제안한다. 인지 라디오 대역 안에서 전체 네트워크 영역에 걸친 공통 채널을 확보하는 것이 어렵기 때문에, 대부분의 멀티 인터페이스 멀티 홉 인지 라디오 네트워크는 라이센스 사용자의 채널 사용 현황과 같은 제어 정보의 교환을 위해인지 라디오 대역 밖에 제어 채널을 두고 하나의 인터페이스를 제어 채널에 고정시켜 할당한다. 그러나 이러한 방식은 네트워크 인터페이스의 낭비를 초래한다. 이 연구는 인지 라디오 노드들이 다수의 데이터 채널을 통해 이웃 노드들과 연결되는 클러스터 구조 하에서 멀티 채널 상황에서의 숨겨진 노드 문제없이 데이터 채널과 제어 채널을 수시로 번갈아 가며 접근하는 방식에 대하여 고찰한다. 시뮬레이션을 사용하여 제안한 방식의 성능을 측정한다. 시뮬레이션 결과를 통해 제안한 방식이 하나의 네트워크 인터페이스를 제어 채널에 고정적으로 할당하여 데이터 전송을 하지 않는 방법에 비해 더 높은 네트워크 처리량을 보임을 확인한다.