In this study, we estimated nitrogen dioxide (NO₂) concentrations in microenvironments where residential indoor, residential outdoor, other indoors, and transportation using measured personal exposure and multiple linear regression analysis of time-weighted average model, and compared with measured NO₂ concentration in microenvironments. Measured residential indoor, outdoor and other indoor NO₂ concentration was 22.22±9.59 ppb, 23.64±9.62 ppb, and 22.07±13.90 ppb, respectively. NO₂ concentrations in residential indoor and outdoor, total outdoor, other indoor, and transportation by multiple regression analysis were significantly estimated as 20.48 ppb, 32.79 ppb, 24.35 ppb, and 28.82 ppb, respectively (p= 0.000). Measured and estimated NO₂ concentration were similar with each other, therefore NO₂ concentrations in each microenvironment were able to be estimated using time-weighted average model and personal exposure with multiple regression analysis.

Recently, the characteristic of plant production systems in Korea has been changed with the strong trends of integration and large scale, using environmental control techniques. To satisfy this change successfully, first of all, the environmental prediction inside the system must be preceded. While many environmental prediction models for plant production system were developed by many persons, each model cannot be applied to the every situation without the perfect understanding of source codes and the technical modification. The purpose of this study is building the environmental prediction model to predict and evaluate the environment inside the system numerically, and also developing the multipurpose program available for practical design. The model consisted of the basic system model, the cultivation related model and the environmental control related model. The contents of each model are as follows : the basic system model is dealing with thermal and light environments, soil environment and ventilation : the cultivation related model with soil and hydroponic cultures ; and the environmental control related model with thermal curtain and heat exchanging system. The environmental prediction model was developed using a common simulation program, PCSMP, so that it could be easily understood and modified by anyone. Finally, the model was executed and verified through comparison between simulated and measured results for soil culture, and both results showed good agreements.

Chloride penetration into concrete is the main cause of the corrosion of steel in concrete structures exposed to chloride-rich environments. As a preventive or remedial method, surface treatments on concrete have been increasingly applied to both new and existing concrete structures to combat this problem. So far, knowledge of how a surface treatment reduces chloride diffusion is limited and the relationship between chloride diffusion resistance and surface treatment parameters, such as thickness, porosity and diffusion coefficient, has not been quantitatively identified. In this paper, chloride ion penetration modeling is performed to predict the service life of the surface treated concrete.

A new prediction scheme has been proposed for the robust teleoperation in a non-visible environment. The positioning error caused by the time delay in the non-visible environment has been compensated for by the Smith predictor and the sensory data have been estimated by the Grey model. The Smith predictor is effective for the compensation of the positioning error caused by the time delay with a precise system model. Therefore the dynamic model of a mobile robot has been used in this research. To minimize the unstable and erroneous states caused by the time delay, the estimated sensor data have been sent to the operator. Through simulations, the possibility of compensating the errors caused by the time delay has been verified using the Smith predictor. Also the estimation reliability of the measurement data has been demonstrated. Robust teleoperations in a non-visible environment have been performed with a mobile robot to avoid the obstacles effective to go to the target position by the proposed prediction scheme which combines the Smith predictor and the Grey model. Even though the human operator is involved in the teleoperation loop, the compensation effects have been clearly demonstrated.

To project the effects of climate-induced change on aquatic environments, it is necessary to determine the thermal constraints affecting different fish species and to acquire time series of the current and projected water temperature (WT). Assuming that a nonlinear regression between the WT at individual stations and the ambient air temperature (AT) at nearby weather stations could represent the best relationship of air-water temperature, This study estimates future WT using a general circulation model (GCM). In addition, assuming that the grid-averaged observations of AT correspond to the AT output from GCM simulation, this study constructed a regression curve between the observations of the local WT and the concurrent GCM-simulated surface AT. Because of its low spatial resolution, downscaling is unavoidable. The projected WT under global warming scenario A2 (B2) shows an increase of about 1.6 (0.9 ) for the period 2080-2100. The maximum/minimum WT shows an amount of change similar to that of the mean values. This study will provide guidelines for decision-makers and engineers in climate-induced river environment and ecosystem management.

매년 수질안전관리와 관련한 사건사고는 끊임없이 발생하고 있으며, 과거의 여러 사례에서 보여지듯이 수질오염으로 인한 피해는 후대까지 지속되는 인류의 끔찍한 재앙을 낳았다. 물은 인간을 비롯한 모든 생태계에 있어 가장 밀접하고도 필수적인 요소이기 때문에 철저한 유지 및 관리가 필요하다. 하지만 인간의 물 공급원인 호수나 하천은 지형적 특성상 오염 후 회복이 어려우며, 경제적인 부분은 물론, 획기적인 수질정화기술이 제시됨에도 불구하고 인구증가와 활발한 인간활동으로 그 수준을 따라가지 못하는 실정이다. 이를 위해 본 연구에서는 사용자의 편의를 위해 Matlab GUI로 제작한 수질의 오염정도를 간단히 예측해 볼 수 있는 수질 예측 모델에 대해 소개하고자 한다. 본 연구에서 소개하는 수질 예측 모델은 well-mixed, steady state라는 가정 하에 자연수역의 형태와 외부 오염 유입 등을 고려하여 알고자하는 지점의 수질 위험정도 판단이 용이하다. 또한 편리한 조작과 간단한 데이터 입력만으로도 수질오염정도의 판단 기준이 되는 여러 지표로 분석 가능하기 때문에 환경공학도들의 자가학습 툴(Self-Learning Tool)로도 효과적일 것으로 기대된다.

The plant habitat is moved by change of growth environment due to global warming. And it have to need seed germination and successful settlement of seedling in new habitat. This study aims to supply basic data for predicting change of habitat of Dendropanax morbifera Lev., warm temperate tree in Korea, by global warming. Characteristics of seed germination of D. morbifera was studied in different temperature and light conditions. Firstly, fruit and non-fleshed seed were saw without cold treatment. Second, each fruit and non-fleshed seed were treated in wet cold and dry cold conditions at 4°C for 3 months, and it were saw in 10, 15, 20, 25, 30°C conditions. After cold treatment at 4°C, non-fleshed seed shows high germination ratio of 87%, 53%, 77%, 63%, 23% in 10°C, 15°C, 20°C, 25°C, and 30°C, respectively. Also, in filed test, non-fleshed seed was high in 69.2% and in non-light condition. However, it did not shown germinated seed in light condition. In conclusion, germination of D. morbifera mainly controlled by non-light condition in temperature after cold treatment for about 3 months on 4°C.

This study forecasts changes in thermal environment and microclimate change per new building construction and assignment of green space in urban area using Computational Fluid Dynamics(CFD) simulation. The analysis studies temperature, humidity and wind speed changes in 4 different given conditions that each reflects; 1) new building construction; 2) no new building construction; 3) green spaces; and 4) no green spaces. Daily average wind speed change is studied to be; Case 2(2.3 m/s) ＞ Case 3. The result of daily average temperate change are; Case 3(26.5℃) ＞ Case 4(24. 6℃) ＞ Case 2(23.9℃). This result depicts average of 2.5℃ temperature rise post new building construction, and decrease of approximately 1.8℃ when green space is provided. Daily average absolute humidity change is analysed to be; Case 3(15.8 g/kg') ＞ Case 4(14.1 g/kg') ＞ Case 2(13.5 g/kg'). This also reveals that when no green spaces is provided, 2.3 g/kg' of humidity change occurs, and when green space is provided, 0.6 g/kg change occurnd 4(1.8 m/s), which leads to a conclusion that daily average wind velocity is reduced by 0.5 m/s per new building construction in a building complex.

해양환경 하에서 염화물의 침투를 억제하여 부식 위험을 최소화함으로써 콘크리트 구조물의 공용기간을 연장할 수 있다. 효과적으로 구조물을 관리하기 위해 적절하게 유지관리하는 것이 필요하다. 본 연구에서는 효과적인 유지관리 전략을 세우기 위한 보수된 구조물의 유지관리비용 평가와 연계하여 구조물의 사용수명을 정량적으로 평가하는 방법을 제안하였다. Fick의 제2법칙으로부터Crank-Nicolson법에 기초한 유한 차분법을 제안하여 보수되지 않은 콘크리트 구조물과 보수된 콘크리트 구조물의 염화물 이온 분포를 예측하였다. 이를 이용하여 보수에 의해 연장 가능한 사용수명과 목표한 공용기간 동안에 필요한 보수 횟수를 평가하였다. 게다가보수 횟수와 콘크리트 교체 비용을 고려하여 총 유지관리 비용을 산출하였다. 마지막으로 제안된 방법의 적용성 검토를 위해 수치해석예제를 제시하였다.

탄산화는 콘크리트 내부의 알칼리성 수화생성물과 대기 중의 탄산가스가 반응하는 것을 의미하며, 탄산화에 의한 철근부식은 철근 콘크리트의 내구성을 저하시키는 주요원인 중의 하나이다. 본 논문에서는 국내에서 광범위하게 시공된 교량구조물에 대한 실태조사를 이용하여 교량구조물이 위치한 환경에 따른 탄산화의 영향을 파악하였다. 또한 계측결과들을 바탕으로 탄산화에 의한 구조물의 내구적 파괴확률을 신뢰성 이론을 기반으로 하여 분석하고, 국내 시방서에서 제시하는 목표파괴확률을 기준으로 대상구조물의 내구수명을 평가하였다. 현장실험결과를 토대로 한 탄산화의 분석결과 교량의 사용년수가 증가함에 따라 탄산화깊이는 증가함을 보였으며, 교량구조물의 탄산화 속도 분석결과 하천교량에 비하여 도심지 및 해상 교량의 탄산화 속도가 1.6-1.9배 빠르게 나타났다. 또한, 교량구조물의 내구수명을 파악한 결과 하천 교량에 비하여 도심지 및 해상 교량의 내구수명은 약 2.4-3.3배 적게 나타났다.

일반적으로 일반대기중의 CO2 농도는 낮기 때문에 자연상태에서는 중성화정도는 매우 느리게 된다. 따라서 콘크리트의 중성화 정도를 평가하기 위해서는 일반적으로 진행속도를 빠르게 하기 위하여 촉진 시험조건하에서 진행하게 된다. 따라서 본 논문은 CO2의 확산 및 Ca(OH)2와의 반응을 바탕으로한 수학적 모델을 통하여 일반대기환경하에서의 콘크리트 중성화 진행을 예측하고자 한다. 이를 위하여 본 논문에서는 촉진 중성화시험을 통하여 얻어진 실험치와 가장 유사한 CO2 확산계수를 채택하여 일반대기환경에서의 중성화진행을 예측하고자 하였다. 그 결과 CO2 확산계수를 이용한 수학적 모델을 통하여 마감재 종류에 관계없이 일반대기환경에서의 콘크리트 중성화진행속도를 예측할 수 있었다.

The purpose of this research was develop tailored landslide hazard assessment table (LHAT) in Gyeongsangbuk-do Province and propose building strategies on environmental information system to estimate landslide hazard area according to LHAT. To accomplish this purpose, this research investigated factors occurring landslide at 172 landslide occurred sites in 23 city and county of Gyeongsangbuk-do Province and analyzed what factors effected landslide occurrence quantity using the multiple statistics of quantification method(Ⅰ). The results of analysis, factors affecting landslide occurrence quantity were shown in order of slope position, slope length, bedrock, aspect, forest age, slope form and slope. And results of the development of LHAT for predict mapping of landslide-susceptible area in Gyeongsangbuk-do Province, total score range was divided that 107 under is stable area(Ⅳ class), 107～176 is area with little susceptibility to landslide(Ⅲ class), 177～246 is area with moderate susceptibility to landslide(Ⅱ class), above 247 area with severe susceptibility to landslide(Ⅰ class). According to LHAT, this research built landslide attribute database and made 7 digital theme maps at mountainous area located in Goryeong Gun, Seongju-Gun, and Kimcheon-City. The results of prediction on degree of landslide hazard using environmental information system, area with little susceptibility to landslide(Ⅲ class) occupied 65.56% and severe susceptibility to landslide(Ⅰ class) occupied 0.51%.

Numerical simulation is essential to indicate the flow of the atmosphere in the region with a complicated topography which consists of many mountains in the inland while it is neighboring the seashore. Such complicated topography produces land and sea breeze as the mesoscale phenomenon of meteorology which results from the effect of the sea and inland. In the mesoscale simulation examines, the change of the temperature in relation to the one of the sea surface for the boundary condition and, in the inland, the interaction between the atmosphere and land surface reflecting the characteristic of the land surface. This research developed and simulated PNULSM to reflect both the SST and vegetation effect as a bottom boundary for detailed meteorological numerical simulation in coastal urban area. The result from four experiments performed according to this protocol revealed the change of temperature field and wind field depending on each effect. Therefore, the lower level of establishment of bottom boundary suitable for the characteristic of the region is necessary to figure out the atmospheric flow more precisely, and if the characteristic of the surface is improved to more realistic conditions, it will facilitate the simulation of regional environment.

Interior space in most buildings is divided into several zones. The most important factors relating to the indoor air environment are temperature, airflow, humidity, and contaminant concentration. An integrated multizone model to predict these environmental factors simultaneously was developed. Also, a computer program for this model was written by the language of VISUAL BASIC. The proposed model was applied to a apartment with five rooms that had been tested by Chung11). Comparison of predicted results by this study with measured results by Chung showed that their variations were within 14% for airflow rates, 1% for temperatures, 12% for humidities, and 5% for concentrations. It was seen that the opening operation schedule of building has a significant effect on the air moisture and contaminant removal. Thus, this model may be available for predicting the indoor air environment and may be contributed to design the ventilation plan for controling of indoor air quality.