• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.6
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• pp.437-443
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• 2009

Impact echo method estimating the soundness of concrete measures the dynamic elastic modulus of specimens which are different with static elastic modulus tested by uni-axial compression test. Thus, this paper investigates the relationships between dynamic and static elastic modulus based on in-situ concrete cores. Also, dynamic elastic modulus was compared with compressive strength. Concrete cores were obtained from about 20 to 70 years concrete structures at three different harbors which were Incheon, Wando, and Masan in Korea. In order to investigate the influence of exposure condition on the relationship, air zone, splash zone, and tidal zone were selected. Different harbors showed the different relationships between dynamic and static elastic modulus, but exposure conditions have no influence on the relationship between dynamic and static elastic modulus. Also, the relationship between dynamic elastic modulus and compressive strength has the same tendency as the relationship between dynamic and static elastic modulus. The relationship equations were proposed to estimate the relationships properly.

• The Korean Journal of Applied Statistics
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• v.31 no.1
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• pp.77-96
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• 2018

A reverse mortgage provides a pension until the death for the insured or last survivor. Long-term risk management is important to estimate the contractual period of a reverse mortgage. It is also necessary to study prediction methods of mortality rates that appropriately reflect the improvement trend of the mortality rate since the extension of the life expectancy, which is the main cause of aging, can have a serious impact on the pension financial soundness. In this study, the Lee-Carter (LC) model reflects the improvement in mortality rates; in addition, multiple life model are also applied to a reverse mortgage. The mortality prediction method by the traditional LC model has shown a dramatic improvement in the mortality rate; therefore, this study suggests mortality projection based on the projection of the skewness for the mortality that has been applied to appropriately reflect the improvement trend of the mortality rate. This paper calculates monthly payments using future mortality rates based on the projection of the skewness of the mortality. As a result, the mortality rates based on this method less reflect the mortality improvement effect than the mortality rates based on a traditional LC model and a larger pension amount is calculated. In conclusion, this method is useful to forecast future mortality trend results in a significant reduction of longevity risk. It can also be used as a risk management method to pay appropriate monthly payments and prevent insufficient payment due to overpayment by the issuing institution and the guarantee institution of the reverse mortgage.

• Journal of Environmental Policy
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• v.5 no.4
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• pp.127-154
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• 2006

It has been widely accepted that the environment is an important determining factor of human health. Appreciating the relationship between the environment and human health, Korean government has begun to deal with issues of environmental health. The government proclaimed the year of 2006 to be the first year of Environmental Health and established "The Environmental Health Plan for the next 10 Year". In order to achieve the goals in the plan, there are necessary considerations such as support systems for environment health related research, investigation, law, institution, administration, and so forth. This study suggests basic principles required to establish a legal regime of environmental health which is to implement the environmental health policies in Korea. Several cases of foreign legislation and policy relevant to environmental health are reviewed. Also, existing related legal system in Korea are analysed considering legal and institutional elements for establishing an effective environmental health policy. The main purpose of amending legal system related environmental health is to protect both public health and the soundness of ecosystem. To reach the goals effectively, the concept of 'environmental health' should be clearly established and presented. In addition, an advanced prevention system, including investigation and prevention of the cause of environmental diseases and risk assessment based on the precautionary principle, are substantial in the environmental health legislation. Also the environmental health law should guarantee public participation in decision making as well as the first consideration of susceptible or vulnerable population. This study concludes that the expected legislation related to environmental health should be a nonnative instrument not only for integrating each environmental protection scheme but also for establishing and implementing the policy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.8-13
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• 2018

A fluid-structure interaction analysis should be performed to evaluate the behavior of the internal fuel and its influence in order to confirm the structural soundness of the fuel tank against external impacts. In the past, fluid-structure interaction analyses have been limited to the obtention of numerical simulation results due to the need for considerable computational resources and excessive computation time. However, recently, computer performance has been dramatically improved, enabling complex numerical analyses such as fluid-structure interaction analysis to be conducted. Lagrangian and Euler coupling methods and Lagrangian based analysis methods are mainly used for fluid-structure interaction analysis. Since both of these methods have their advantages and disadvantages, it is necessary to select the more appropriate one when conducting a numerical analysis. In this study, a numerical analysis of a crash impact test for a fuel tank is performed using ALE. The purpose of the numerical analysis is to estimate the possibility of failure of the fuel tank mounted inside the container when it is subjected to a crash impact. As a result of the numerical analysis, the fluid behavior inside the fuel tank is investigated and the stress generated in the fuel tank and the container structure is calculated, thereby enabling the possibility of fuel tank failure and leakage of the internal fluid to be evaluated.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.4
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• pp.374-382
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• 2009

Steam generator(SG) tube, as a barrier isolating primary to the secondary coolant system of nuclear power plants(NPP), must maintain the structural integrity far the public safety and its efficient power generation capacity. And SG tubes bearing defects must be timely detected and taken repair measures if needed. For the accomplishment of these objectives, SG tubes have been periodically examined by eddy current testing(ECT) on the basis of administrative notices and intensified SG management program(SGMP). Stress corrosion cracking(SCC) on the SG tubes is not easily detected and even missed since it has lower signal amplitude and other disturbing factors against its detection. However once SCC is developed, that can cause detrimental affects to the SG tubes due to its rapid propagation rate. Accordingly SCC is categorized as prime damage mechanism challenging the soundness of the SG tubes. In this study, reproduced EDM notch specimens are examined for the detectability and quantitative characterization of the axial ODSCC by +PT MRPC probe, containing pancake, +PT and shielded pancake coils apart in a single plane around the circumference. The results of this study are assumed to be applicable fur providing key information of engineering evaluation of SCC and improvement of confidence level of ECT on SG tubes.

• Economic and Environmental Geology
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• v.51 no.2
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• pp.131-147
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• 2018

In the present study, the safety of the near surface disposal facility for low- and intermediate-level radioactive waste (LILW) is examined based on the fluid-flow simulation model. The effects of the structural design and hydrological properties of the disposal system are quantitatively evaluated by estimating the flux of infiltrated water at the boundary of the structure. Additionally, the safety margins of the disposal system, especially for the cover layer and vault, are determined by applying the various scenarios with consideration of possible facility designs and precipitation conditions. The overall results suggest that the disposal system used in this study is sufficiently suitable for the safe operation of the facility. In addition, it is confirmed that the soundness of both the cover layer and the vault have great impact on the safety of the facility. Especially, as shown in the vault degradation scenario, capability of the concrete barrier of the vault make more positive contribution on the safe operation of the facility compared to that of the cover layer.

• Environmental and Resource Economics Review
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• v.23 no.4
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• pp.643-665
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• 2014

We study the optimal policy of the contracual arrangement in raising the debt-to-equity ratio for oil, gas and mining project finance deals. We investigate the impact of the optimal contractual relationship between counterparties on the soundness of projects, differing in output price volatility and country risk. Key findings are: first, the existence of EPC sponsors and off-takers generally raises the debt-to-equity ratio. In particular, EPC sponsors and off-taking sponsors jointly mitigate the credit risk caused by counntry risk. Seocond, off-taking and EPC contracts jointly help mitigate the credit risk caused by the country risk, rather than the price volatility. Indeed, the contractual structure raises the debt-to-equity ratio.

• Journal of Energy Engineering
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• v.27 no.2
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• pp.14-25
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• 2018

The combined cycle power plant has a cycle of operating the gas turbine with fuel, such as natural gas, and then producing steam using residual heat. The fuel gas is supplied to the gas turbine at a level of 4 to 5 MPa, $200^{\circ}C$ through a compressor and a heat exchanger. In this study, the risk assessment method considering the piping system stress was carried out for safe operation and soundness of the gas fuel supply piping system. The API 580/581 RBI code, which is well known for its risk assessment techniques, is limited to reflect the effect of piping stress on risk. Therefore, the systematic stress of the pipeline is analyzed by using the piping analysis. For the study, the piping system stress analysis was performed using design data of a gas fuel supply piping of a combined cycle power plant. The result of probability of failure evaluated by the API code is compared to the result of stress ratio by piping analysis.

• Journal of the Korean Society of Food Culture
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• v.8 no.3
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• pp.249-255
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• 1993

To minimize the waste amount of surface layer kochujang during aging, the effects of the three finishing methods(nothing, salt scatering and Polyethylene film on the kochujang surface) and sunning(conventional aging method) or nonsunning aging(cap covering) on water content, redness and spreadability, film forming yeast occurance and salinity of surface layer kochujang during 120 days aging were investigated. In the case of sunning aging, film forming yeast was not visually found on the surface. The surface layer kochujang was so low spreadability(zero) and very high salinity(18-30%) that could not eat. However, the aging method after PE-film covering on the kochujang surface, and then cap covering(nonsunning) was very effective in keeping of soundness of surface layer kochujang without film forming yeast growth on the surface kochujang, especially was greatly effective in keeping of redness, moderate moisture content and spreadability. The PE-film and cap covering aging were effective in prevention of water evaporation and $CO_2$ release, and in accumulation of ethanol and organic acids between the PE-film and surface layer of kochujang.

• Journal of Korea Technology Innovation Society
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• v.10 no.3
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• pp.580-603
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• 2007

This paper examines accountability trend for government supported research institutes through the analysis of what aspects of accountability have been emphasized in the institute evaluation from 1991 to 2005. We divided research period into pre-research council period(1991-1998) and post-research council period(1999-2005). In pre-research council period, we find four kinds of accountability for government supported research institutes, that is, compliance accountability for regulation, managerial accountability, performance accountability and social accountability and great emphasis has been put on compliance accountability for regulation and managerial accountability. In post-research council period, financial accountability for soundness has been added to the above four kinds of accountability and great emphasis has been put on performance accountability and managerial accountability, especially performance accountability. The concrete contents of an accountability has been also changed between pre-research council period(1991-1998) and post-research council period(1999-2005). Regulation accountability in the pre-research council period are related to conforming to government rules for institute operation and regulation defining institute function for reformulation, but in post-research council period, it has been focused on rules for the rationalization of management. Managerial accountability has been changed from emphasizing on management efficiency approximately to focusing on more specific management efficiency like the appropriateness of personnel management, the efficiency of budget management and project management, reasonableness of evaluation and compensation. Performance accountability has been changed in methods for measuring performance, in the pre-research council period, it has been taken quantitative method for measuring productivity, but, in post-research council period, qualitative approach like objective management has been complemented. Finally, accountability for government supported research institutes has been changed towards being concrete in many sided accountabilities and focusing on performance accountability.