• 환경영향평가
• /
• 제12권5호
• /
• pp.323-340
• /
• 2003

There have been persistent civil appeals in Ansan area against the odor and aerosols emitted from nearby Banwol/Sihwa industrial complex. A fundamental solution for the good air quality has not been addressed yet in spite of the continuous counterplan to reduce odor emission. A systematic and scientific study is needed to examine the reason for the odor episode and to predict the impact coverage of odor pollution. An approach by computational simulation is considered to be adequate to investigate the transportation and the dispersion processes of air pollutants blown by sea breeze toward the coastal city, Ansan. This study has employed various dispersion models to simulate the transportation and the dispersion processes of odor pollutants by a local circulation between land/sea breeze using the data set of emission rates of odorous species from the Banwol/Sihwa industrial complex.

• 산업기술연구
• /
• 제24권A호
• /
• pp.47-57
• /
• 2004

Industrial efforts for increased market sales have directed towards the development and implementation of on-line marketing systems under recent e-business environment. Internet-based shopping mall is one of the most popular system. A business process model for an intermediary type shopping mall using IDEF0 has been presented in this study. Specific efforts have been focused on defining and analyzing a diversity of business processes embedded in practical B2B and B2C mall system operations. We first briefly examined the considered system with IDEF0 design. We then defined fundamental business processes within shopping mall systems. Upon careful examination and analysis of them, a detailed business process model based on IDEF methodology has been designed. The results in this study may well form a conceptual framework for shopping mall development and operations.

• 대한전자공학회논문지
• /
• 제17권2호
• /
• pp.37-52
• /
• 1980

산업프로세스(industrial _Process)가 점차 복잡하여지고 자동화됨에 따라 계통(system)의 신뢰도를 높이고 인간의 한계능력을 해결하기 위하여 경보분석(alarm analysis)흑은 고장진단(fault diagnosis)의 필요성이 절실화 되어 가고 있다. 본 논문에서는 화학 반응기 (chemical reactor)의 고장진단을 위한 방법으로 시이퀸스 콤퓨터 프로그램밍(sequence computer programming )에 의한 "사전(dictionary)" 작성방법이 시도 되었고 실험을 통해 그 유용성이 입증 되었다. 그리고 점차 복잡되어가고 있는 경보 시스템(alarm system)을 단순화 시킬 수 있는 결과 시스템 설계에 대한 제안을 마련하였다.

• 산업경영시스템학회지
• /
• 제39권3호
• /
• pp.147-155
• /
• 2016

Industry 4.0's goal is the 'Smart Factory' that integrates and controls production process, procurement, distribution and service based on the fundamental technology such as internet of the things, cyber physical system, sensor, etc. Basic requirement for successful promotion of this Industry 4.0 is the large supply of semiconductor. However, company I who produces dicing blades has difficulty to meet the increasing demand and has hard time to increase revenue because its raw material includes high price diamond, and requires very complex and sensitive process for production. Therefore, this study is focused on understanding the problems and presenting optimal plan to increase productivity of dicing blade manufacturing processes. We carried out a study as follows to accomplish the above purposes. First, previous researches were investigated. Second, the bottlenecks in manufacturing processes were identified using simulation tool (Arena 14.3). Third, we calculate investment amount according to added equipments purchase and perform economic analysis according to cost and sales increase. Finally, we derive optimum plan for productivity improvement and analyze its expected effect. To summarize these results as follows : First, daily average blade production volume can be increased two times from 60 ea. to 120 ea. by performing mixing job in the day before. Second, work flow can be smoother due to reduced waiting time if more machines are added to improve setting process. It was found that average waiting time of 23 minutes can be reduced to around 9 minutes from current process. Third, it was found through simulation that the whole processing line can compose smoother production line by performing mixing process in advance, and add setting and sintering machines. In the course of this study, it was found that adding more machines to reduce waiting time is not the best alternative.

• KSBB Journal
• /
• 제20권4호
• /
• pp.291-298
• /
• 2005

본 연구는 재조합 대장균과 S.cerevisiae의 발효공정에서 형광스펙트럼 데이터를 수집하였으며, SOM을 이용하여 형광스펙트럼 데이터를 특정 그룹으로 분류하고 발효공정을 분석하고자 하였다. 배출가스 내 이산화탄소농도와 세포농도 같은 공정변수들은 SOM 알고리즘으로부터 얻은 분산 및 정규화된 가중치들과 좋은 연관성을 나타내었다. 전체 스펙트럼 데이터의 분류는 생물공정 모델링을 위한 매우 중요한 단계인데 그 이유는 몇몇 여기파장과 방출파장의 유의한 조합들이 전체영역의 스펙트럼 데이터로부터 추출되기 때문이다. 예를 들면, 본 연구에서 SOM을 이용하여 추출한 98개의 스펙트럼 데이터의 예제들은 부분최소자승법이나 감독신경망 (supervised neural network)을 이용한 공정의 모델링에 사용될 수 있다.

• Industrial Engineering and Management Systems
• /
• 제4권1호
• /
• pp.75-81
• /
• 2005

Borror et al. discussed the EWMA(Exponentially Weighted Moving Average) chart to monitor the count of defects which follows the Poisson distribution, referred to the $EWMA_c$ chart, as an alternative Shewhart c chart. In the $EWMA_c$ chart, the Markov chain approach is used to calculate the ARL (Average Run Length). On the other hand, in order to monitor the process fraction defectives P in high-yield processes, Xie et al. presented the CCC(Cumulative Count of Conforming)-r chart of which quality characteristic is the cumulative count of conforming item inspected until observing $r({\geq}2)$ nonconforming items. Furthermore, Ohta and Kusukawa presented the $CS(Confirmation Sample)_{CCC-r}$ chart as an alternative of the CCC-r chart. As a more superior chart in high-yield processes, in this paper we present an $EWMA_{CCC-r}$ chart to detect more sensitively small or moderate shifts in P than the $CS_{CCC-r}$ chart. The proposed $EWMA_{CCC-r}$ chart can be constructed by applying the designing method of the $EWMA_C$ chart to the CCC-r chart. ANOS(Average Number of Observations to Signal) of the proposed chart is compared with that of the $CS_{CCC-r}$ chart through computer simulation. It is demonstrated from numerical examples that the performance of proposed chart is more superior to the $CS_{CCC-r}$ chart.

• 산업경영시스템학회지
• /
• 제44권2호
• /
• pp.85-92
• /
• 2021

Ambient Air Vaporizer (AAV) is an essential facility in the process of generating natural gas that uses air in the atmosphere as a medium for heat exchange to vaporize liquid natural gas into gas-state gas. AAV is more economical and eco-friendly in that it uses less energy compared to the previously used Submerged vaporizer (SMV) and Open-rack vaporizer (ORV). However, AAV is not often applied to actual processes because it is heavily affected by external environments such as atmospheric temperature and humidity. With insufficient operational experience and facility operations that rely on the intuition of the operator, the actual operation of AAV is very inefficient. To address these challenges, this paper proposes an artificial intelligence-based model that can intelligent AAV operations based on operational big data. The proposed artificial intelligence model is used deep neural networks, and the superiority of the artificial intelligence model is verified through multiple regression analysis and comparison. In this paper, the proposed model simulates based on data collected from real-world processes and compared to existing data, showing a 48.8% decrease in power usage compared to previous data. The techniques proposed in this paper can be used to improve the energy efficiency of the current natural gas generation process, and can be applied to other processes in the future.

• Korean Chemical Engineering Research
• /
• 제59권4호
• /
• pp.521-531
• /
• 2021

진공가압함침공정(Vacuum Pressure Impregnation, VPI)은 발전기, 전동기 등 대형 회전기에 사용되는 고정자 권선에 에폭시 계열의 레진을 코팅시켜 물성을 강화하는 공정이다. VPI 공정 중 진공과 가압과정에서 에폭시 레진의 기화에 의해 레진 가스가 발생하고, 함침공정이 끝나고 경화를 위해 탱크 개방 시 레진 가스가 제거되지 않고 탱크 밖으로 유출된다. 유출된 레진 가스가 작업장 전체에 확산 시 화재, 폭발 및 호흡기 문제와 같은 안전 환경 문제가 있으므로 공정 내 레진 가스 배출시스템이 필요하다. 따라서, 본 연구에서는 VPI 공정에서 발생한 레진 가스를 배출하는 시스템을 설계하기 위해 전산유체역학(Computational Fluid Dynamics, CFD)을 이용하여 공기 유입구·배출구의 위치에 따른 배출효율에 대한 사례연구를 진행하였다. 본 연구의 최적의 배출시스템을 활용 시 1,800초 이내 90%이상의 레진 가스를 배출할 수 있으며, 레진 가스의 폭발하한계(Low Explosive Limit, LEL)이하로 레진 가스의 분율을 낮출 수 있었다.

• 대한산업공학회지
• /
• 제41권1호
• /
• pp.25-33
• /
• 2015

From the viewpoint of applications to manufacturing, data mining is a useful method to find the meaningful knowledge or information about states of processes. But the data from manufacturing processes usually have two characteristics which are multicollinearity and imbalance distribution of data. Two characteristics are main causes which make bias to classification rules and select wrong variables as important variables. In the paper, we propose a new data mining procedure to solve the problem. First, to determine candidate variables, we propose the multiple hypothesis test. Second, to make unbiased classification rules, we propose the decision tree learning method with different weights for each category of quality variable. The experimental result with a real PDP (Plasma display panel) manufacturing data shows that the proposed procedure can make better information than other data mining procedures.

• 한국산학기술학회논문지
• /
• 제15권10호
• /
• pp.6176-6186
• /
• 2014

본 연구는 간호학생의 간호 수기술 향상을 위해 사전 동영상 학습방법을 활용한 기본간호학 실습 교육평가방법의 학습동기, 학업적 자기효능감 및 문제해결과정을 파악하고자 하는 상관성 조사연구였다. 학습동기와 학업적 자기효능감은 간호과 선택동기, 전공만족도, 기본간호학실습 만족도, 사전 동영상 시청의 도움정도, 체크리스트 활용 실기평가의 적절성에 따라 통계적으로 차이가 있었다. 문제해결과정은 전공만족도, 기본간호학실습만족도, 사전 동영상 시청의 도움 정도, 체크리스트 활용 실기평가의 적절성에 따라 통계적으로 차이가 있었다. 학습동기는 학업적 자기효능감 및 문제해결과정과, 학업적 자기효능감은 문제해결과정과 유의한 정적상관관계를 나타냈다. 결론적으로, 사전 동영상 학습방법을 활용한 기본간호학실습 교육평가방법은 간호학생의 학습동기, 학업적 자기효능감 및 문제해결과정과 관련이 있었다.