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어린이 천식과 주거환경적 위험요인에 대한 환자-대조군 연구
황규석,윤충식,최재욱,Hwang, Gyu-Seok,Yoon, Chung-Sik,Choi, Jae-Wook 한국환경보건학회 2012 한국환경보건학회지 Vol.38 No.3
Objective: We performed this study to determine the association between childhood asthma and residential environment risk factors including VOCs and formaldehyde exposure. Methods: We selected an asthma group (30) and a control gorup (30) through physicain diagnosis and assessed the VOCs and formaldehyde levels of exposure of elementary school children in Seoul. Results: In the results, there were no significant differences in socioeconomic factors between case and control groups. However, there were significant differences in family asthma history, amount of sunlight, level of humidity and number of household residents (p < 0.05). The level of VOC (toluene, ethylbenzene, stylene, m,p-xylene) exposure level of the case group was significantly higher than that of the control group (p < 0.05) and the result of logistic regression showed that asthma family history, amount of humidity and number of household residents were significant predictors of childhood asthma (p < 0.05). Conclusion: Some residential environments such as lower amounts of sunlight, greater amounts of humidity and smaller numbers of household residents and VOC exposure were determinded as risk factors for childhood asthma.
운전절차 합성을 위한 제약조건 전파 기반의 통합 프레임워크
황규석,허보경 한국화학공학회 2001 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.39 No.3
화학공장의 운전절차 자동 합성은 공장 안전을 향상시킬 뿐 아니라 설계 비용을 줄여 주지만 기존 방법들은 조작에 의한 공정상태의 변화를 모사하는 방법, 운전목표 달성에 필요한 조작과 중간목표의 선택 방법에 많은 한계를 가지고 있다. 따라서 본 연구에서는 목표사이의 복잡한 상호작용으로 인한 조작선택의 어려움을 해결하고 공정지식을 보다 효과적으로 표현하기 위해 필요한 제약조건 전파 기반의 통합 프레임워크를 제안하였다. 제안된 방법론은 중간목표사이의 상호작용이 매우 심한 공정에 적용하여 그 유효성을 입증하였다. The automatic synthesis of operating procedures for chemical plants improves plant safety and reduces design costs. However, the existing operating procedure synthesis techniques have limitations in simulating a change of process states by the operation and selecting operations and subgoals needed to achieve the operational goal. So in this study, we have proposed the integrated framework based on constraint propagation to resolve problems about operation selection due to subgoal interaction among subgoals and to effectively use the process knowledge. The proposed methodology has been successfully applied to the process with serious subgoal interaction.
황규석,허보경,안대명 한국화학공학회 1996 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.34 No.6
보일러 플랜트의 운전관리 미숙(오조작, 오판단)으로 인해 발생하는 shutdown을 예방하기 위한 운전 지원용 전문가 시스템을 개발하였다. 본 연구에서는 대상공정 과 거동에 대한 symbolic modeling을 실시하고, 조작에 비한 공정상태 변화의 모사방법과 상황 의존적인 문제를 해결하는 방법을 제안하였다. 또한, 위험상황과 운전상황의 인식에 필요한 지식 을 일반화하여, 오판단과 오조작으로 인한 보일러의 이상상태를 조작에 미리 앞서서 예측할 수 있는 방법을 제시하였다. 개발된 시스템을 실제 공성에 적용하여 제시한 방법이 유용한 것임을 검증하였다. An operation aiding expert system is developed for preventing an unexpected shutdown caused by operation errors or misjudgements in boiler plants. Based on symbolic model about the plant structure and the behavior characteristics, the change of process states is simulated. And the method for solving context-dependent problem is suggested. With generalized knowledges for the recognition of operational situations and hazardous conditions, a strategy is suggested for anticipating accidents caused by operation errors or misjudgements in advance. By the results of the application of this system to the real plant, it is shown that the methodology suggested in this study is useful.
화학공정의 위험상태 인식을 위한 지식 표현에 관한 연구
황규석,안대명 한국산업안전학회 1996 한국안전학회지 Vol.11 No.3
A system was developed that could predict hazardous states for safe operation of chemical plants. This system aimed to prevent hazards of chemical processes from misoperation before real operation. In this study, a data base was organized which consisted of all hazards in the chemical processes. The structure of process was represented by signed direct graph(SDG) of NODEs and ARCs. Each NODE and ARC have property variables ; connected structure and state of processes etc. The hazards that could be occurred in processes were divided into two classes ; one is by operation of unit and the other is by hazardous materials. Using Hazardous States Transition Network, we could recognize transition progress of process states.
졸-겔법을 이용한 $(Ba_{1-x}Sr_x)TiO_3$ 박막의 제조 및 특성
황규석,김병훈 한국세라믹학회 1995 한국세라믹학회지 Vol.32 No.4
In this study, to prepare the dielectric (Ba, Sr)TiO3 thin films by the sol-gel process, Titaminum (IV) sio-propoxide (Ti[OCH(CH3)2]4), Ba and Sr acetate were used for sol and thin films were prepared by dip-coating process. Stability of sol decreased with the increase of Sr, and thickness of thin films were obtained 0.13~0.17${\mu}{\textrm}{m}$ by 1 coating cycle. Transmittance of amorphous thin films heated at 500 and 55$0^{\circ}C$ was very good, and crystallization tendency of thin films according to heat-treatment temperature and crystallization characteristics of thin films heated at 11$0^{\circ}C$ for 3 hrs were analysed. As a result, good perovskite structure was obtained higher than 100$0^{\circ}C$, and tetragonality of thin film was decreased but pyrochlore was formed with increasing Sr. In case of addition to substitute 0.4mol% Sr for Ba, dielectric constant was 288 and loss factor (tan $\delta$) was 0.04.
졸-겔법에 의한 $TiO_2$ 박막의 특성에 관한 연구
황규석,김병훈 한국세라믹학회 1995 한국세라믹학회지 Vol.32 No.3
to prepare the TiO2 thin films, acetyl-acetone(2.4-pentanedione)(1 : 1 molar ratio) was dissolved in the propanol solution of titanium(IV)isopropoxide(Ti[OCH(CH3)2]4). Al, Cr and Sb in the form of soluble salt and niobium ethoxide were added s dopants, respectively. Thin films were coated by the dip-coating method and characteristics were investigated by XRD, SEM and conductance meter. As a result, viscosity of sol was maintained below 4 centi Poise more than 20 days, and crystal growth and diminution of resistivity occurred as the heat treatment temperature increased. The grains grew over 1${\mu}{\textrm}{m}$ and the lowest resistivity was obtained when Nb was added at 130$0^{\circ}C$.
저온도포열분해에 의해 제조된 Pb(Zr, Ti)O$_3$ 박막의 에피탁시와 결정화도에 미치는 전열처리 시간의 영향
황규석,이형민,김병훈 한국세라믹학회 1998 한국세라믹학회지 Vol.35 No.9
Pb(Zr, Ti)O3 (PZT) (Zr:Ti= 52: 48) thin films were prepared on MgO(100) substrates by dipping-py-rolysis process using metal naphthenates as starting materials. Thin films were fabricated by spin coating technique and the precursor films were prefired at 20$0^{\circ}C$ in air for 0.5, 1, 2, 3, and 24 h followed by final heat treatment at 75$0^{\circ}C$ for 30min. Film prefired for 24 h lost orientational properties and pole figure analysis showed the lost of the epitaxial relationship between the films and substrate while highly a/c-axis oriented thin films were obtained for the samples prefired for 1, 2, and 3h.
도포 열분해법을 이용한 Bi$_4$Ti$_3$O$_{12}$제조에 관한 연구
황규석,이형민,김병훈 한국세라믹학회 1998 한국세라믹학회지 Vol.35 No.9
Bismuth titanate thin films were prepared on {{{{ { SrTiO}_{3 } }}(100) and Si(100) substrates by dipping-pyrolysis pro-cess using metal naphthenates as starting materials. crystallinity and in-phase alignment of the films were analyzed by X-ray diffraction $\theta$-2$\theta$ scans and $\beta$ scans (pole-figures) respectively. Highly c-axis-oriented {{{{ { { {Bi }_{4 }Ti }_{3 }O }_{12 } }} thin films with smooth surfaces were obtained after heat treatment at 75$0^{\circ}C$ on {{{{ { SrTiO}_{3 } }}(100) sub-strate while the films grown of Si(100) exhibited polycrstalline characteristics. C-axis oriented film show-ed an epitaxial relationship with the {{{{ { SrTiO}_{3 } }} substrate.