• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.50-57
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• 2010

Various installation faults may lie in fasteners in the construction of a direct-fixation track by the top-down method. At an extreme, they may cause excessive interaction between the train and track, compromise the running safety of the train, and cause damage to the track components. Therefore, the faults need to be kept within the allowable level through an investigation of their effects on the interactions between the train and track. In this study, the vertical dynamic stiffness of fasteners in installation faults was measured based on the dynamic stiffness test by means of an experimental apparatus that was devised to feasibly reproduce gap faults. This study proposes an effective analytical model for a train-track interaction system in which most elements, except the nonlinear wheel-rail contact and some components that behave bi-linearly, exhibit linear behavior. To investigate the effect of the behavior of fasteners in gap faults in a direct-fixation track on the vehicle and track, vehicle-track interaction analyses were carried out, targeting key review parameters such as the wheel load reduction factor, vertical rail displacement, rail bending stress, and mean stress of the elastomer. From the results, it was noted that the gap faults in the concrete bearing surface of a direct-fixation track need to be limited for the sake of the long-term durability of the elastomer than for the running safety of the train or the structural safety of the track.

• 한국지열·수열에너지학회논문집
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• 제17권1호
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• pp.14-22
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• 2021

Drilling equipment is an essential part used in various fields such as construction, mining, etc., and it has drawn increasing attention in recent years. The drilling method is generally divided into three types. There are a top hammer method that strikes on the ground, a DTH (Down-The-Hole) method that directly strikes a bit in an underground area, and a rotary method that drills by using rotational force. Among them, the DTH method is most commonly used because it enables efficient drilling compared to other drilling methods. In the conventional DTH hammer, the valve between the piston and the bit is opened and closed using a face to face method. In order to improve the power of the DTH hammer, a DTH hammer with foot valve which is capable of instantaneous opening and closing is used in the drilling field. In this study, we designed a lab-scale DTH hammer with the foot valve, and manufactured an evaluation device for the experiment of the DTH hammer. In addition, we analyzed the performance of the DTH hammer adopted with foot valve according to the pressure range of 3-10 bar. As a result, the internal pressure distribution in the DTH hammer was experimentally analyzed, and then, the movement of the piston according to the pressure was predicted. We believe that this study provides the useful results to explain the performance characteristics of the DTH hammer with the foot valve.

• 복식
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• 제63권6호
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• pp.56-68
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• 2013

A purpose of this study is to do fundamental research of construction of coat patterns in the Daehan Empire in order to make replicas of the costumes. This study is composed of literature research, investigation of artifacts, and experiment of pattern making. The results of this study are as follows. First, even if the 15th Court Dress Rules regulated color, fabric, number of flower, width of braid, and size of button, there was no regulation regarding the shape of the coat. The analysis of the photos in those periods shows that the style of the tailcoat was different from that of today in the length of the front, the shape of breast and collar. Second, six artifacts in the collection showed that the shoulder line and the sideline were located on the further rear side than the current tailcoat. This can be confirmed in the western and Japanese pattern book, and especially the pattern drafting method in the books published in Japan in 1900s is different from current one in setting base lines of front bodice and back bodice. As a result, based on several experiments, this study proposes how to make coat patterns. The shoulder line, the sideline, and the princess line should be located in the back of the dress similar to the shape of swallowtail coats of 1900s. The front bodice should be constructed without the composition line in order to add embroidery on it. The collar, which shape looks like long half moon, should form V-shape neckline in the front breast when adjusting dress. The sleeves should be constructed top and down, and it should curve more than the modern design.

• 한국건설관리학회논문집
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• 제19권4호
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• pp.93-101
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• 2018

생명체와 같이 살아있는 도시는 성장과 소멸의 과정을 거치는 생태계와 같은 특징을 가지고 있다. 최근의 도시들은 자연발생되는 경우 보다는 설계자에 의해 설계되는 경우가 많은 데, 만약 도시가 최적화되어 설계되지 않으면, 이를 개선하는 것이 매우 어렵다. 이로 인하여, 많은 사람들은 잘못된 설계로 인한 불편을 감수하고, 그러한 도시에 적응하여 살아가게 된다. 그러므로 설계단계에서부터 오류없이 최적화된 도시설계가 이루어지는 것이 중요하다. 도시가 최적화 설계되지 못하는 이유들 중 하나는 복잡성인데, 과거의 도시 설계방법에서 도시의 복잡성 문제를 해결할 때에는 주로 경험과 지식에 의한 하향식 문제해결 방법이 적용되었다. 그런데 이는 도시의 생태적 특성을 반영하지 않는 설계방법으로, 생태계의 생성원리를 적용한 상향식 문제해결 방법이 적용되지 못하게 된다. 따라서 본 연구에서는 작은 단위문제 해결의 합이 큰 단위문제 해결이 되는 인공 생명의 일반원리를 도시설계방법에 적용하였다. 그 결과, 다양한 도시설계 대안들을 도출할 수 있었으며, 도출된 대안들은 제한된 모델링 임에도 불구하고 전문가가 설계 한 것과 차이가 없다는 점과 향후 개발의 가능성이 있다는 점을 확인할 수 있었다.

• Journal of Information Processing Systems
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• 제16권3호
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• pp.612-628
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• 2020

This paper presents a new approach for detecting abnormal behaviors in complex surveillance scenes where anomalies are subtle and difficult to distinguish due to the intricate correlations among multiple objects' behaviors. Specifically, a cascaded probabilistic topic model was put forward for learning the spatial context of local behavior and the temporal context of global behavior in two different stages. In the first stage of topic modeling, unlike the existing approaches using either optical flows or complete trajectories, spatio-temporal correlations between the trajectory fragments in video clips were modeled by the latent Dirichlet allocation (LDA) topic model based on Markov random fields to obtain the spatial context of local behavior in each video clip. The local behavior topic categories were then obtained by exploiting the spectral clustering algorithm. Based on the construction of a dictionary through the process of local behavior topic clustering, the second phase of the LDA topic model learns the correlations of global behaviors and temporal context. In particular, an abnormal behavior recognition method was developed based on the learned spatio-temporal context of behaviors. The specific identification method adopts a top-down strategy and consists of two stages: anomaly recognition of video clip and anomalous behavior recognition within each video clip. Evaluation was performed using the validity of spatio-temporal context learning for local behavior topics and abnormal behavior recognition. Furthermore, the performance of the proposed approach in abnormal behavior recognition improved effectively and significantly in complex surveillance scenes.

• Steel and Composite Structures
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• 제17권6호
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• pp.891-906
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• 2014

This study aims to present a three dimensional finite element model to investigate the wave propagation in a concrete filled steel tubular column (CFSC) due to transient impact load. Both the concrete and steel are regarded as linear elastic material. The impact load is simulated by a semi sinusoidal impulse. Besides the CFSC models, a concrete column (CC) model is established for comparing under the same loading condition. The propagation characteristics of the transient waves in CFSC are analyzed in detail. The results show that at the intial stage of the wave propagation, the velocity waves in CFSC are almost the same as those in CC before they arrive at the steel tube. When the waves reach the column side, the velocity responses of CFSC are different from those of CC and the difference is more and more obvious as the waves travel down along the column shaft. The travel distance of the wave front in CFSC is farther than that in CC at the same time. For different wave speeds in steel and concrete material, the wave front in CFSC presents an arch shape, the apex of which locates at the center of the column. Differently, the wave front in CC presents a plane surface. Three dimensional effects on top of CFSC are obvious, therefore, the peak value and arrival time of incident wave crests have great difference at different locations in the radial direction. High-frequency waves on the waveforms are observed. The time difference between incident and reflected wave peaks decreases significantly with r/R when r/R < 0.6, however, it almost keeps constant when $r/R{\geq}0.6$. The time duration between incident and reflected waves calculated by 3D FEM is approximately equal to that calculated by 1D wave theory when r/R is about 2/3.

• 건축역사연구
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• 제19권3호
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• pp.7-29
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• 2010

The form of the Wangheungsa Temple's wooden pagoda site is that of the traditional form of the wooden pagodas constructed during the Baekjae Period. Likewise, it is an important ruin for conducting research on the form and type of the wooden pagodas constructed during the Baekjae Period. In particular, the method used for the installation of the central pillar's cornerstone is a new technique. The purpose of this research is to restore the ruin of the Wangheungsa Temple's wooden pagoda of the Baekjae Period that remains at the Wangheungsa Temple's wooden pagoda site. Until now, research conducted on the wooden pagoda took place mostly centered on the Hwangryongsa Temple's wooden pagoda. Meanwhile, the reality concerning Baekjae's wooden pagoda is one in which there were not many parallel cases pertain to the design for restoration. This research paper wants to conduct academic examination of the Wangheungsa Temple's wooden pagoda to organize the intention of design and design process in a simple manner. This research included review of the Baekjae Period's wooden pagoda related ruins and the review of the existing wooden pagoda ruin to analyze the wooden pagoda construction technique of the era. Then, current status of the Wangheungsa Temple's wooden pagoda site is identified to define the characteristics of the wooden pagoda, and to set up the layout format and the measure to estimate the size of the wooden pagoda in order to design each part. Ultimately, techniques and formats used for the restoration of the wooden pagoda were aligned with the wooden pagoda of the Baekjae Period. Basically, conditions that can be traced from the current status of the Wangheungsa Temple site excavation using the primary standards as the standard. Wangheungsa Temple's wooden pagoda was designed into the wooden pagoda of the Baekjae's prosperity phase. The plane was formed into $3{\times}3$ compartments to design into three tier pagoda. The height was decided by factoring in the distance between the East-West corridors, size of the compartment in the middle, and the view that is visible from above the terrace when entering into the waterway. Basically, the origin of the wooden structure format is based on the Goguryeo style, but also the linkage with China's southern regional styles and Japan's ancient wooden pagoda methods was factored in. As for the format of the central pillar, it looks as if the column that was erected after digging the ground was used when setting up the columns in the beginning. During the actual construction work of the wooden pagoda, central pillar looks as if it was erected by setting up the cornerstone on the ground. The reason that the reclaimed part of pillar that use the underground central cornerstone as the support was not utilized, was because the Eccentric Load of the central pillar's cornerstone was factored in the state of the layers of soil piled up one layer at a time that is repeated with the yellow clay and sandy clay and the yellow clay that were formed separately with the $80cm{\times}80cm$ angle at the upper part of the central pillar's cornerstone was factored in as well. Thus, it was presumed that the central pillar was erected in the actual design using the ground style format. It is possible to presume the cases in which the reclaimed part of pillar were used when constructed for the first time, but in which central pillar was installed later on, after the supplementary materials of the underground column is corroded. In this case, however, technique in which soil is piled up one layer at a time to lay down the foundation of a building structure cannot be the method used in that period, and the reclamation cannot fill up using the $80cm{\times}80cm$ angle. Thus, it was presumed that the layers of soil for building structure's foundation was solidified properly on top of the central pillar's cornerstone when the first wooden pagoda construction work was taking place, and that the ground style central pillar was erected on its upper part by placing the cornerstone once again. Wangheungsa Temple's wooden pagoda is significant from the structure development aspect of the Korean wooden pagodas along with the Hwangryongsa Temple's wooden pagoda. Wangheungsa Temple's wooden pagoda construction technique which was developed during the prosperity phase of the Baekjae Period is presumed to have served as a role model for the construction of the Iksan Mireuksa Temple's wooden pagoda and Hwangryongsa Temple's wooden pagoda. With the plan to complement the work further by excavating more, the basic wooden pagoda model was set up for this research. Wangheungsa Temple's wooden pagoda was constructed as at the Baekjae Kingdom wide initiative, and it was the starting point for the construction of superb pagoda using state of the art construction techniques of the era during the Baekjae's prosperous years, amidst the utmost interest of all the Baekjae populace. Starting out from its inherent nature of enshrining Sakyamuni's ashes, it served as the model that represented the unity of all the Baekjae populace and the spirit of the Baekjae people. It interpreted these in the most mature manner on the Korean peninsula at the time.

• 한국건축시공학회지
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• 제18권4호
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• pp.363-373
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• 2018

고층 공동주택에서 화재시 현관문을 통해 탈출이 불가능할 경우를 대비해 발코니를 통해 피난이 가능하도록 피난시설을 설치한다. 이는 공동주택 세대의 양방향 피난이 가능하게 하며, 이로 인해 인명피해를 줄일 수 있다. 본 연구에서는 양방향 피난시설인 경량 칸막이, 발코니 대피 공간, 실내형 하향식 피난구의 특징을 살펴보고 이들의 문제점을 개선한 실외형 하향식 피난구를 제시하고 경제성에 대해 분석하였다. 화재 발생 시 피난자는 전통식 피난구를 사용할 때보다 하향식 피난구를 사용할 때 능동적인 탈출 가능 여부를 더 자율적으로 판단 할 수 있다. 따라서 피난자의 피난방식에 따라 피난소요시간에 미치는 영향을 고려하여 계단식과 하향식 피난구를 통한 4가지 피난방식의 피난 소요시간은 시뮬레이션 pathfinder를 활용하여 비교분석하였다. 피난 소요 시간 단축을 위한 적합한 대피방식을 예측 분석 판단하였다. 본 연구의 결과 고층 아파트 하향식 피난구는 계단식보다 총 피난소요시간을 단축할 수 있는 것으로 분석되었다.

• 한국전산구조공학회논문집
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• 제37권3호
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• pp.205-216
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• 2024

최근 원자력 지진 PSA(Probabilistic Safety Assessment)를 토대로 산업시설물의 지진 PSA를 수행하는 연구가 진행되었다. 해당 연구는 원자력 발전소와 산업시설물의 차이를 파악하고, 최종적으로 운영정지를 목표로 하는 고장수목(Fault Tree)를 구축한 후 시각적 확률도구인 베이지안 네트워크(Bayesian Network, BN)으로 변환하였다. 본 연구는 선행연구를 기반으로 지진으로 유발된 구조손상으로 인해 발생 가능한 화재･폭발에 대해 PSA를 수행하고자 하였다. 이를 위해 화재･폭발을 사건수목(Event Tree)으로 표현하고, BN으로 변환하였다. 변환된 BN은 화재･폭발 모듈로서 선행연구에서 제시된 고장수목 기반 BN과 연계되어 최종적으로 지진 유발 화재･폭발 PSA를 수행할 수 있는 BN 기반 방법론이 개발되었다. 개발된 BN을 검증하기위해 수치예제로서 가상의 가스플랜트 Plot Plan을 생성하였고, 가스플랜트의 설비 종류가 구체적으로 반영된 대규모 BN을 구축하였다. 해당 BN을 이용하여 지진 규모에 따른 전체시스템의 운영정지 확률 및 하위시스템들의 고장확률 산정과 더불어 역으로 전체시스템이 운영 정지되었을 때 하위시스템들의 영향도 분석과 화재･폭발 가능성을 산정하여 다양한 의사결정을 수행할 수 있음을 제시함으로써 그 우수성을 확인하였다.

• 한국치위생학회지
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• 제8권4호
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• pp.205-217
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• 2008

The purpose of this study was to provide information on the development of an oral-health promotion program geared toward office workers. The subjects in this study were 240 employees at the headquarters of S construction company. After a survey was conducted in July and August 2008, the answer sheets from 208 respondents were gathered, and 191 answer sheets were analyzed except 17 unanalyzable ones. The findings of the study were as follows: 1. In regard to subjective oral health status, the largest number of the participants that accounted for 37.2% found their mouth to be neither healthy nor unhealthy. The greatest number of them that represented 58.1% had never visited a dentist's office to receive preventive treatment. 2. Regarding relationship between toothbrushing education experience and toothbrushing frequency, the most common toothbrushing frequency was three times a day( 46.5%) among the company employees who had ever received that education. In the event of the office workers without that experience, the most prevalent frequency was three times(63.6%). The toothbrushing frequency was statistically significantly different according to the toothbrushing education experience(p<0.05). As to the relationship of toothbrushing education experience to tooth- brushing method, the largest number(48.2%) of those who had ever received that education brushed their upper and lower teeth along with the gums by rotating the toothbrush downward from the top and upward from the bottom respectively. In the event of the office workers without that experience, 49.4 percent brushed their teeth and gums by rotating the toothbrush up and down. Thus, whether they had ever received education about toothbrushing made a statistically significant difference to their toothbrushing method(p<0.05). 3. As a result of evaluating their oral health belief by utilizing a five-point scale, they got a mean of 2.95. In each area of oral health belief, they got the best marks in benefit(3.66), salience(3.42), barrier(2.84), susceptility(2.58) and seriousness(2.23). Given the above-mentioned finding of the study, two sorts of oral health beliefs, which are benefit and salience, should be stressed in the development of oral health education programs that cater to company employees. And sustained research efforts should be channeled into finding out the relationship between oral health and actual oral health care.