BIM기반 MEP공사 시공용 도면 작성 자동화 프로세스 제안

최창현,권대용,조상호,김주형,Choi, Chang-Hyun,Kwon, Dae-Yong,Cho, Sang-Ho,Kim, Ju-Hyung 한국BIM학회 2020 KIBIM Magazine Vol.10 No.4

Shop drawing tasks conducted after finishing coordinated or engineering design have great influences on the quality and cost of a project. However, despite the development of commercial BIM applications, shop drawings have mainly produced manually in certain engineering fields. Incorrect shop drawings with human errors have occurred various problems such as cost overrun, time delay and reworks. An automated shop drawing publishing from BIM is expected to resolve these problems. Despite attempts for automate shop drawing production, the field of mechanical, electrical and plumbing (MEP) is yet regarded challenging due to complexity of components and connection. In this research, we develop a process for automated producing 3D MEP shop drawings in BIM environment as following steps: to analyze conventional MEP shop drawing process, to identify detailed process that can be automated, to classify existing MEP objects and assign codes usable in BIM, and to develop an application. The validation of automated process is conducted against 10 clean room projects in which MEP is more complex and its cost is higher than other projects in terms of productivity and workers' satisfaction. Results show that the number of manpower for shop drawing is reduced by 30%, and the working time is shortened by 31%. Personal opinions of involved practitioners is interpreted as positive as the average rate of agrement on practicability, easy-to-use and necessary retouch tasks is around 66%.

가시광선-근적외선 반사스펙트럼을 이용한 쇠고기의 신선도 평가

최창현,김종훈,김용주,Choi, Chang-Hyun,Kim, Jong-Hun,Kim, Yong-Joo 한국축산식품학회 2011 한국축산식품학회지 Vol.31 No.1

본 연구에서는 유통현장에서 실시간으로 쇠고기 신선도를 측정하기 위해 가시광선-근적외선 반사 스펙트럼을 이용하여 쇠고기 신선도에 영향을 미치는 인자와 설정된 저장기간에 대하여 예측 모델을 개발하고 검증하였다. 쇠고기 시료는 총 216개를 사용하였으며 0-14일의 기간 동안 2일 간격으로 가시광선-근적외선 반사 스펙트럼을 측정한 후, 쇠고기의 신선도에 영향을 미치는 인자인 총균수, pH, VBN, TMA, TBA값을 공인된 방법을 이용하여 측정하였다. 예측모델은 다중회귀분석 방법과 최적 변수 선택이 가능한 stepwise 방법을 이용하여 개발하였으며, 예측모델의 선정은 결정계수, 오차, RPD를 이용하였다. 예측모델의 검증은 미지의 시료를 이용하였으며 그 결과 결정계수, 오차, RPD는 총균수에서 각각 0.74, 0.64, 2.75 Log CFU/$cm^2$, VBN은 각각 0.73, 1.45, 2.00 mg%, TMA는 각각 0.70, 0.19, 2.58 mg%, TBA값은 각각 0.73, 0.13, 2.77 mg MA/kg로 비교적 안정된 예측성능을 보여 주었다. 저장기간에 따른 예측모델의 검증결과는 결정계수, 오차, RPD가 각각 0.77, 1.94일, 2.53으로 실험 시 저장기간이 2일 간격인 점을 고려할 때, 비교적 높은 정밀도를 보이고 있음을 알 수 있다. pH의 예측성능은 결정계수, 오차, RPD가 각각 0.43, 0.10, 1.10로 다른 신선도 인자에 비해 낮은 결과를 보여 주었다. 본 연구에서는 가시광선-근적외선 분광분석법을 이용하여 쇠고기 신선도의 비파괴 평가에 대한 가능성을 제시하였으나 유통현장에서 적용을 위해서는 보다 많은 시료의 확보를 통한 예측모델의 신뢰성 향상과 stepwise방법으로 선정된 파장 영역을 기본으로 하는 부분최소자승법, 인공지능 등의 다양한 알고리즘의 적용을 통한 성능개선이 필요할 것으로 판단된다. The objective of this study was to develop models to predict freshness factors (total viable counts (TVC), pH, volatile basic nitrogen (VBN), trimethylamine (TMA), and thiobarbituric acid (TBA) values) and the storage period in beef using a visible and near-infrared (NIR) spectroscopic technique. A total of 216 beef spectra were collected during the storage period from 0 to 14 d at a $10^{\circ}C$ storage. A spectrophotometer was used to measure reflectance spectra from beef samples, and beef freshness spectra were divided into a calibration set and a validation set. Multi-linear regression (MLR) models using the stepwise method were developed to predict the factors. The MLR results showed that beef freshness had a good correlation between the predicted and measured factors using the selected wavelength. The correlation of determination ($r^2$), standard error of prediction (SEP), and ratio of standard deviation to SEP (RPD) of the prediction set for TVC was 0.74, 0.64, and 2.75 Log CFU/$cm^2$, respectively. The $r^2$, SEP, and RPD values for pH were 0.43, 0.10, and 1.10; those for VBN were 0.73, 1.45, and 2.00 mg%; those for TMA were 0.70, 0.19, and 2.58 mg%; those for TBA values were 0.73, 0.13, and 2.77 mg MA/kg; and those for storage period were 0.77, 1.94, and 2.53 d, respectively. The results indicate that visible and NIR spectroscopy can predict beef freshness during storage.

콤바인 예취부 고장진단을 위한 예취 칼날부의 진단 시스템 개발(I) - 진동 및 부하 신호 분석 -

최창현,김용주,김종혁,문정환,Choi, Chang-Hyun,Kim, Yong-Joo,Kim, Jong-Hyuck,Mun, Joung-Hwan 한국농업기계학회 2007 바이오시스템공학 Vol.32 No.3

The purpose of this study is to develop a measurement system of cutter conditions for combine header diagnosis during rice harvesting. A load cell was installed at the locker-arm to measure load fluctuation and an acceleration senor was used to monitor vibration signal of cutter bar. The data were collected from a paddy field during harvesting. The tests were conducted with a normal cutter, a loosened cutter, a broken cutter, and a worn-out connecter pin at the field. The vibration signals converted by FFT (Fast Fourier Transformation), filtered, and normalized. The load data and peak values of vibration signals in four different frequency ranges were used to determine the cutting operation and the cutter conditions of combine. The multiple comparison tests showed that the load data and peak values of vibration signals were important to monitor the cutting operation and cutter conditions of combine header.

맥류 연구의 과거, 현재, 그리고 미래

김경민(Kyeong-Min Kim),강천식(Chon-Sik Kang),김양길(Yang-Kil Kim),김경훈(Kyeong-Hoon Kim),박종호(Jong-Ho Park),윤영미(Young-Mi Yoon),박형호(Hyoung-Ho Park),정한용(Han-Yong Jeong),최창현(Chang-Hyun Choi),박진희(Jinhee Park),김영진(You 한국육종학회 2020 한국육종학회지 Vol.52 No.S

Barley and wheat are a major food crop of humans, along with rice, soybean and corn. A systematic breeding program for Korean barley began in 1906 with selection and introduction breeding. In 1908, landrace barley was collected, and breeding focused on selection and introduction for high yielding varieties until the 1970s. In the 1980s and 1990s, breeding was carried out for diversity; thereafter, we aimed to improve quality, productivity and lodging tolerance that can be applied to the paddy field in Korea. Since 2010, the major result of breeding was shortening cultivation to approximately 6–12 days, making a double cropping system possible in the paddy field in Korea. Yield has increased by 1.2 times from 438 kg/10 a in the 1960s to 536 kg/10 a in the 2010s, and farm yield has increased by 1.7 times. In addition, as cultivation safety has been enhanced, the varieties have also improved, such as the covered barley used in making tea and other processing products. In case of wheat, up to now forty cultivars have been developed in Korea. In the early stage, we developed a domestic wheat variety that was early maturing and high yielding. As a result, the maturation time of wheat planted in the 1970s to 2010 was shortened (from 13 to 30 days), while productivity increased by 30% from 408 kg/10 a in the 1970s to 532 kg/10 a in 2010. In recent years, there have been remarkable efforts for a more stable production by focusing on increasing disaster and pest resistance due to climate change. In addition, a wheat variety discrimination marker was developed using a variety-specific marker, and selection was made using a trait-specific marker at the early stage of breeding to enhance breeding efficiency. In the 2000s, winter cereals for forage have been promoted to expand forage production and to replace imported feed grains. Therefore, winter cereal that is useful for feed, such as rye, oat, and triticale, have had various varieties and safe production techniques developed. Currently, our research goal for winter cereals for feed is to develop a double-cropping adaptation and abiotic stress tolerance cultivar, and safe production in paddy field. Hence, aggressive action is needed to support the strategic survival of the Korean wheat and barley industry. Barley is a health food that requires a multifaceted effort to improve breeding efficiency, develop varieties that contain large amounts of functional components and are more resistant to stronger biotic and abiotic stresses in response to climate change. It is necessary to recognize the role of wheat and barley as the second main crop after rice, and to improve the self-sufficiency rate of these crops for the health and food industry crisis of Korea.

이송 사과의 내부 결함 검출을 위한 투과 스펙트럼의 분광특성 분석

최창현 ( Chang Hyun Choi ),장현준 ( Hyeon Jun Jang ),홍성호 ( Sung Ho Hong ),주재옥 ( Jae Ok Joo ),이대현 ( Dae Hyun Lee ) 한국농업기계학회 2015 한국농업기계학회 학술발표논문집 Vol.20 No.2

지식검색 서비스에서의 소셜 네트워크 기반 영향력 지수 알고리즘

최창현(Chang-Hyun Choi),박건우(Gun-Woo Park),이상훈(Sang-Hoon Lee) 한국컴퓨터정보학회 2009 韓國컴퓨터情報學會論文誌 Vol.14 No.10

집단지성을 이용한 지식검색 서비스는 개방적 구조와 축적된 자료를 공유할 수 있다는 커뮤니티적인 특성으로 큰 인기를 얻고 있다. 하지만 방대한 지식공유 속에서 사용자가 진정으로 원하는 답변 획득은 점점 더 어려워지고 있다. 최근 알고리즘에서 가장 정교하다고 평가 받는 구글을 통해 상위에 랭크된 검색 결과들 중에는 집단지성을 통해 구축된 위키피디아, 야후 Q/A와 같은 소셜 검색엔진의 검색 결과들이 상당수 존재한다. 본 논문은 대부분의 질문은 인간으로부터 문제해결의 실마리를 얻을 수 있다는 점과 온라인상의 사용자에 대한 연구를 통해 지식검색 서비스 사용자 중 영향력 자를 찾는 것에 목적을 둔다. 이에 국내 소셜 검색엔진의 대표인 네이버 지식iN을 중심으로 지식검색내의 사용자 활동성과 신뢰성을 소셜 네트워크 기반으로 정의하고, 사용자간의 관계를 중앙성으로 분석하는 영향력 지수 알고리즘을 제안한다. 제안된 알고리즘을 통한 영향력 지수는 지식검색 서비스에서 문제 해결의 실마리를 가진 사용자를 랭킹화 함으로써 질문에 적합하고신뢰성 있는 답변을 하는 사용자를 분별하는 지표가 되며 이를 바탕으로 지식검색 서비스내의 영향력 자를 식별 가능하게 된다. 이는 지식검색 서비스사용자의 최대 목적인 사용자가필요로 하는 정보와 지식을 보다 용이하게 획득 가능케 함으로써 검색 만족도 향상에 큰 기여를 할 것이다. Knowledge retrieval service that uses collective intelligence which has special quality of open structure and can share the accumulative data is gaining popularity. However, acquiring the right needs for users from massive public knowledge is getting harder. Recently, search results from Google which is known for it's exquisite algorism, shows results for collective intelligence such as Wikipedia, Yahoo Q/A at the highest rank. Objective of this paper is to show that most answers come from human and to find the most influential people in on-line knowledge retrieval service. Hereupon, this paper suggest the influence value calculation algorism by analyzing user relation as centrality which social network is based on user activeness and reliance in Naver 지식iN. The influence value calculated by the suggested algorism will be an important index in distinguishing reliable and the right user for the question by ranking users with troubleshooting solutions in the knowledge retrieval service. This will contribute in search satisfaction by acquiring the right information and knowledge for the users which is the most important objective for knowledge retrieval service.

정신장애인 ‘당사자’ 운동의 가능성: 정신장애인 운동 내 당사자성 논란과 정신장애차별주의적 보조금 지원 정책의 문제점

최창현 ( Choi Chang-hyun ) 한국문화인류학회 2022 韓國文化人類學 Vol.55 No.3

This study dealt with the conflict in an organization that tried to resolve negative perceptions of the mentally challenged people by hosting an event called Mad Pride Seoul; it was among the various attempts to form a mentally challenged ‘led’ movement that began in Korea in the 2010s. In this context, I carried out this study to reveal the factors affecting the survival of the social movement. In my role as researcher, I entered an organization that had prepared the ‘Mad Pride Seoul’ festival and prepared for the festival with them. The organization that I studied exemplifies the mentally challenged-led movement, because the ‘first-personness’ or ‘Dang-sa-ja-sung’ question is critical, because of the problem of determining who can be the subjects of the activism. It is important to note that ‘first-person’ or ‘Dang-sa-ja (Tōjisha)’ is a being in the process of ‘becoming’ through ritualization, and is not made by forcing that being to become itself. However, the people in the organization wanted to stage a recovery of everyday life that could be understood, even if it is too slow for others, instead of a social movement to become the ‘first-person.’ However, the organization which has covered most of the necessary finances with many public and privately subsidized projects have constantly demanded results, which has required their competence. Mentally challenged people in the organization have lost their place amid positive and negative feedback from the subjects of the projects. In the end, the organization lost its power and collapsed, as the ousted people gathered and accused their former representatives. Through this case stud y, I have shown that the method of the projects based on Sanism that supported the survival of the mentally challenged-led movement was the direct cause of conflict within the organization, and it eliminated the possibility of a social movement that focused on the subjectivity of the ‘first-person’.

머신러닝을 이용한 호우피해 예측함수 개발

최창현(Choi, Chang Hyun),김종성(Kim, Jong Sung),김동현(Kim, Dong Hyun),김경훈(Kim, Kyung Hun),김형수(Kim, Hung Soo) 대한토목학회 2017 대한토목학회 학술대회 Vol.2017 No.10

머신러닝 기반의 범주형 호우피해 예측모형 개발

최창현(Choi, Chang Hyun),김종성(Kim, Jong Sung),김동현(Kim, Dong Hyun),이준형(Lee, Jun Hyeong),김형수(Kim, Hung Soo) 대한토목학회 2019 대한토목학회 학술대회 Vol.2019 No.10

ISBM - PP 기술의 현황과 전망

최창현(Chang Hyun Choi),김영우(Young Woo Kim) 한국고분자학회 1995 고분자 과학과 기술 Vol.6 No.6