• Journal of Forest and Environmental Science
• /
• 제28권4호
• /
• pp.205-211
• /
• 2012

Yield tables are a frequently used data base for regional timber resource forecasting. A normal yield table is based on two independent variables, age and site (species constant), and applies to fully stocked (or normal) stands while empirical yield tables are based on average rather than fully stocked stands. Normal and empirical yield tables essentially have many limitations. The limitations of normal and empirical yield tables led to the development of variable density yield tables. Mathematical models for estimating timber yields are usually developed by fitting a suitable equation to observed data. The model is then used to predict yields for conditions resembling those of the original data set. It may be accurate for the specific conditions, but of unproven accuracy or even entirely useless in other circumstances. Thus, these models tend to be specific rather than general and require validation before applying to other areas. Dalbergia sissoo forms a major portion of irrigated plantations in the hot desert of India and is an important timber tree species where stem wood is primarily used as timber. Variable density yield model is not available for this species which is very crucial in long-term planning for managing the plantations on a sustained basis. Thus, the objective of this study was to develop variable density yield model based on the data collected from 30 sample plots of D. sissoo laid out in IGNP area of Rajasthan State (India) and measured annually for 5 years. The best approximating model was selected based on the fit statistics among the models tested in the study. The model develop was evaluated based on quantitative and qualitative statistical criteria which showed that the model is statistically sound in prediction. The model can be safely applied on D. sissooo plantations in the study area or areas having similar conditions.

• 환경영향평가
• /
• 제10권2호
• /
• pp.123-133
• /
• 2001

Gaussian dispersion model is the most widely used tool for the ground level air pollution simulation. Though in spite of the convenience there are important problems on the Pasquill- Gifford' stability classification scheme which was used to define the turbulent state of the atmosphere or to describe the dispersion capabilities of the atmosphere which was each covers a broad range of stability conditions, and that they were very site specific, and the vertical dispersion calculation formula on the case of the unstable atmospheric condition. This paper was carried out to revise the Gaussian dispension model for the purposed of increase the modeling performance and propose the revised model, which was composed of the turbulent characteristics in the unstable atmospheric conditions. The proposed models in this study were composed of the profile method, Monin-Obukhove length, the probability density function model and the lateral dispersion function which was composed of the turbulent parameters, $u_*$(friction velocity), $w_*$(convective velocity scale), $T_L$(lagrangian time scale) for the model specific. There were very good performance results compare with the tracer experiment result on the case of the short distance (<1415m) from the source, but increase the simulation error(%) to stand off the source in the all models. In conclusion, the revised Gaussian dispersion model using the turbulent characteristics may be a good contribution for the development of the air pollution simulation model.

• 한국지진공학회논문집
• /
• 제13권1호
• /
• pp.1-8
• /
• 2009

본 논문에서는 부지응답 해석 시 통제운동 지점의 전단파속도가 부지응답해석에 미치는 영향을 살펴보았다. 내진설계기준 연구(II)(건설교통부, 1997)에서는 '재현주기별 지진가속도의 작용 위치는 "기본적인 지진재해도는 보통암지반을 기준으로 평가한다."라고 정의하고 있다. 그러나 보통암지반(SB)의 전단파속도 범위가 $760m/sec{\sim}1500m/sec$로 폭넓게 분포되어 있어, 부지응답 해석 시 통제운동지점의 선택에 따라 해석의 결과에 차이가 발생할 수 있다. 따라서, 본 논문에서는 국내의 대표적인 해성퇴적지반층인 인천 및 부산지역의 상세부지조사결과를 바탕으로 1차원 등가선형해석을 수행하였다. 통제운동지점인 기반암 전단파속도에 따른 지층내 가속도의 크기 변화, 그리고 이에 따른 액상화 안전율 변화정도를 살펴보았다. 또한, 해석결과와 외국의 내진설계기준을 바탕으로 국내 내진설계기준의 개선방향에 대하여 살펴보았다.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 1996년도 춘계학술대회
• /
• pp.178-178
• /
• 1996

Hepatitis B virus (HBV) infection is one of the serious problems in Southeast Asia including Korea because it causes chronic hepatitis, which can easily be transformed In fatal conditions such as cirrhosis and hepatoma. Even though lots of informations on structural characteristics and gene expression mechanisms have been accumulated, the mechanism for HBV-induced hepatocellular injury which is believed to be the consequences of the immunological response is not well understood. In order tn perform immunopathological studies for prevention and treatment of HBV infection, we designed transgenic mice as a disease model which can mimic HBV infection, In this study, a promoter-HBV DNA fragment for the preparation of HBV transgenic mice has been constructed. To add a proper enzyme site on 5' end of HBV gene, total HBV (subtype adr) gene was inserted into BamHI site of pBluescript SK vector and reextracted by PstI-SacI treatment A liver-specific promoter, rat ${\alpha}$ 2u globulin gene promoter, was insrted to pBluescript SK vector and reextracted by BamHI-PstI treatment, Promoter-HBV DNA was constructed by ligation of two fragments using identical PstI sites. For large scale production of promoter-HBV DNA, it was inserted to BamHI-SacI site of pBluescript SK vector.

• Nuclear Engineering and Technology
• /
• 제44권7호
• /
• pp.745-754
• /
• 2012

The correlations between Large Early Release Frequency (LERF) and Early Fatality need to be investigated for risk-informed application and regulation. In Regulatory Guide (RG) -1.174, while there are decision-making criteria using the measures of Core Damage Frequency (CDF) and LERF, there are no specific criteria on LERF. Since there are both huge uncertainties and large costs needed in off-site consequence calculation, a LERF assessment methodology needs to be developed, and its correlation factor needs to be identified, for risk-informed decision-making. A new method for estimating off-site consequence has been presented and performed for assessing health effects caused by radioisotopes released from severe accidents of nuclear power plants in this study. The MACCS2 code is used for validating the source term quantitatively regarding health effects, depending on the release characteristics of radioisotopes during severe accidents. This study developed a method for identifying correlations between LERF and Early Fatality and validates the results of the model using the MACCS2 code. The results of this study may contribute to defining LERF and finding a measure for risk-informed regulations and risk-informed decision-making.

• 한국토양비료학회지
• /
• 제19권3호
• /
• pp.251-268
• /
• 1986

Selecting a site for the safe disposal of radioactive waste requires the evaluation of a wide range of geologic, mineralogic, hydrologic, and physicochemical properties. Although highly diverse, these properties are in fact interrelated. Site requirements are also diverse because they are influenced by the nature of the radionuclides in the waste, for example, their half-lives, specific energy, and chemistry. A fundamental consideration in site selection is the mineralogy of the host rock, and one of the most ubiquitous mineral groups is clay minerals. Clays and clay minerals as in situ lithologic components and engineered barriers may playa significant role in retarding the migration of radionuclides. Their high sorptivity, longevity (stability), low permeability, and other physical factors should make them a very effective retainer of most radionuclides in nuclear wastes. There are, however, some unanswered questions. For example, how will their longevity and physicochemical properties be influenced by such factors as radionuclide concentration, radiation intensity, elevated temperatures, changes in redox condition, pH, and formation fluids for extended periods of time? Understanding of mechanisms affecting clay mineral-radionuclide interactions under prevailing geochemical conditions is important; however, the utilization of experimental geochemical information related to physicochemical properties of clays and clay-bearing materials with geohydrologic models presents a uniquely challenging problem in that many assessments have to be based on model predictions rather than on experiments. These are high-priority research investigations that need to be addressed before complete reliance for disposal area performance is made on clays and clay minerals.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제24권3호
• /
• pp.13-23
• /
• 2019

The purpose of this study is to suggest conceptual models based on finite numerical method that can be used to assess contaminant transport through subsurface and estimate exposed concentration at contaminated site. This study tested various assumptions of the numerical models for contaminant transport in unsaturated and saturated zones to simulate the pathways to the human exposal point. For this purpose, models for seven possible scenarios of contaminant transport were simulated using the numerical code MODFLOW and MT3D. The simulation results that showed different peak concentrations and travel times were compared. In conclusion, the potential utility of the numerical models in the site specific risk analysis suggested as well as future research ramifications.

• Journal of Biosystems Engineering
• /
• 제33권4호
• /
• pp.260-268
• /
• 2008

Optical diffuse reflectance sensing has potential for rapid and reliable on-site estimation of soil properties. For good results, proper calibration to measured soil properties is required. One issue is whether it is necessary to develop calibrations using samples from the specific area or areas (e.g., field, soil series) in which the sensor will be applied, or whether a general "factory" calibration is sufficient. A further question is if specific calibration is required, how many sample points are needed. In this study, these issues were addressed using data from 42 paddy fields representing 14 distinct soil series accounting for 74% of the total Korean paddy field area. Partial least squares (PLS) regression was used to develop calibrations between soil properties and reflectance spectra. Model evaluation was based on coefficient of determination ($R^2$) root mean square error of prediction (RMSEP), and RPD, the ratio of standard deviation to RMSEP. When sample data from a soil series were included in the calibration stage (full information calibration), RPD values of prediction models were increased by 0.03 to 3.32, compared with results from calibration models not including data from the test soil series (calibration without site-specific information). Higher $R^2$ values were also obtained in most cases. Including some samples from the test soil series (hybrid calibration) generally increased RPD rapidly up to a certain number of sample points. A large portion of the potential improvement could be obtained by adding about 8 to 22 points, depending on the soil properties to be estimated, where the numbers were 10 to 18 for pH, 18-22 for EC, and 8 to 22 for total C. These results provide guidance on sampling and calibration requirements for NIR soil property estimation.

• Nuclear Engineering and Technology
• /
• 제51권6호
• /
• pp.1561-1574
• /
• 2019

A standard form of six stylized human intrusion scenarios for a near-surface disposal facility (e.g. the planned Korean repository, Gyeongju Phase II) is proposed through re-categorization of totally thirty-one past cases reported in public literature. A reference assessment framework for inadvertent human intrusion is newly developed using GENII Version 2 conforming to the ICRP Publication 60 and thereafter. Calculated dose from the assessment framework is verified by comparing with hand calculation results for simplified model equations independently derived. Results from GENII Version 2 and 1.485 show inevitable differences, which is mainly attributed to the difference in the external dose assessment model. If intake dose coefficients in GENII Version 1.485 are modified, the difference can be reduced but still exist to an extent. Through deterministic and probabilistic sensitivity analysis, most affecting four parameters are derived and uncertainties of the parameters are quantified. It is expected that the reference assessment framework together with representative stylized scenarios can be used to do a human intrusion impact assessment for a specific repository using site-specific information. Especially, the past practice of human intrusion impact assessment using GENII Version 1.485 with or without modification may be replaced with the new assessment framework developed in this study.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2019년도 춘계학술대회
• /
• pp.51-52
• /
• 2019

종래에는 해양 및 해안 구조물에 작용하는 주된 외력요소인 파도는 안전성의 측면에 중점하여 다뤄져왔다. 최근 해양 에너지의 개발 및 해양 레저스포츠 등의 다변화된 해양 활동의 수요 증가에 대응하기 위해 특정 해역의 파도의 특징을 정의하기 위한 다양한 연구가 수행되고 있다. 파도의 특징은 장소에 따라 특수하지만, 선행 연구들에서 제안된 활용가능한 스펙트럼 모델은 제한적이다.