• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.415-421
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• 2008

Reinforced concrete starts to corrode when the chloride ion concentration which is the sum of included in concrete and penetrated from environments exceeds a certain level of critical chloride concentration. Therefore each country regulates the upper bounds of chloride amount in concrete and the regulations are different for each country due to its circumstances. In this study, the critical threshold chloride content according to unit cement amount is empirically calculated to propose a reasonable regulation method on the chloride amount. As a result, the critical threshold chloride content increases considerably according to cement content and it agrees with the established theories. The present regulations on total chloride amount 0.3 or 0.6 kg chloride ions per $1\;m^3$ of concrete does not reflect the influences of mix design, environmental conditions and etc. So it can be said that it is more reasonable to regulate the critical threshold chloride content by the ratio of chloride amount per unit cement content than by the total chloride content in $1\;m^3$ of concrete.

• Resources Recycling
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• v.29 no.3
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• pp.43-50
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• 2020

This study reviewed the examples on analyses of the potential impacts to waste management, due to the recent trends of waste trade regulation, and summarized an analysis strategy of the impacts. As a result, a desirable analysis may begin with reasonable estimation of recent waste amounts and flows, and reasonable prediction of the future trends of waste amounts. Then, it is effective to list various key factors and derive future scenarios of the impacts, as well as employ the traditional viewpoints focusing on waste material flow or environmental regulations. The applicable analyses for each scenario can be largely divided into qualitative and quantitative methods. Due to a high uncertainty in the recent international situations with entailing possible innovative economic changes, qualitative methods may be considered in advance, and then quantitative techniques may be utilized to predict gradual changes at relieved uncertainty of the situations. Based on this review so far, proper methodology and procedures for the impact analysis were suggested on recent waste trade conditions in Korea. Given existence of the recent uncertainties such as the health and economic crises, the analysis preferably focused on deriving strategic scenarios with respect to various aspects, and suggested analysis methods applicable to each scenario.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.211-219
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• 2010

The design concept of high speed railway bridges is applied to a method for increasing the stiffness of existing bridge structures considering the impact factor by a static load. Generally, the process of structural design would be relied upon an advanced foreign technology. However, the dynamic amplification factor (DAF) and dynamic capacity assessment of high speed railway bridges may be conducted essentially a detailed estimation because the resonance phenomenon is affected by the long length (380 m) and high speed (300 km/h) moving of a high speed railway (Korea Train eXpress: KTX). Therefore, this study will be examined the dynamic capacity of the typical PSC Box Girder high speed railway bridge efficiently, and offered the basic information for the reasonable structural design. For this, the static analysis is conducted considering the load line diagram of KTX based upon existing references. In addition, the KTX moving load is transformed into the time series load considering various analytical variables. The time history analysis is assessed reasonable using the transformed time series load. At that time, analytical variables for calculating the time series load are considered loading node distance, time increment and KTX velocity variation etc. The dynamic capacity of the PSC Box Girder high speed railway bridge is examined based upon the FE analysis result systematically. The structural safety is assessed quantitatively in accordance with the related regulation of the inside and outside of the country.

• Journal of Radiation Protection and Research
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• v.37 no.4
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• pp.219-225
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• 2012

This study makes differentiated regulations which can maximize the efficiency and convenience of radiation safety regulations by deriving evidence required to establish reasonable safety regulatory structure based on the determination of the levels of actual radiation safety regulations for radiation safety managers to perform radiation safety. We surveyed approximately 10% of radiation safety managers from domestic radiation-using organizations which was based on the Nuclear Safety Act and NUREG Vol. 1~21 of RS-G-1.9 (2005), NRC of IAEA, etc. The radiation safety managers showed the highest level of awareness on the requirements for exposure management ($3.32{\pm}0.910$), and the lowest level on the requirements for record keeping and storage of documents ($2.84{\pm}0.826$). Industrial organizations showed higher levels of awareness than medical organizations whose regulations should be more stringent on requirements of the status and management of radioactive sources, facilities, measurements, pollution control, measuring equipment, monitoring, education and training, and exposure management. This suggests that the actual regulations need to be re-evaluated because it is attributed to the regulations which are statistically significant difference of the levels of radiation safety regulations between industrial organizations and medical organizations. The process of developing regulatory requirements for each characteristic of domestic organizations needs to be done in future studies, as well as safety regulations to maximize convenience should be achieved if radiation safety regulations are conducted in consideration with the characteristics of each organization.

• Journal of Wetlands Research
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• v.21 no.spc
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• pp.90-97
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• 2019

In recent years, flood due to the consecutive storm events have been occurred and property damage and casualties are in increasing trend. This study calls the consecutively occurred storm events as a mega rainfall scenario and the discharge by the scenario is defined as a mega flood discharge. A mega rainfall scenario was created on the assumption that 100-year frequency rainfall events were consecutively occurred in the Gyeongancheon stream basin. The SSARR (Streamflow Synthesis and Reservoir Regulation) model was used to estimate the mega flood discharge using the scenario in the basin. In addition, in order to perform more reasonable runoff analysis, the parameters were estimated using the SCE_UA algorithm. Also, the calibration and verification were performed using the objective functions of the weighted sum of squared of residual(WSSR), which is advantageous for the peak discharge simulation and sum of squared of residual(SSR). As a result, the mega flood discharge due to the continuous occurrence of 100-year frequency rainfall events in the Gyeongan Stream Basin was estimated to be 4,802㎥/s, and the flood discharge due to the 100-year frequency single rainfall event estimated by "the Master Plan for the Gyeongancheon Stream Improvement" (2011) was 3,810㎥/s. Therefore, the mega flood discharge was found to increase about 992㎥/s more than the single flood event. The results of this study can be used as a basic data for Comprehensive Flood Control Plan of the Gyeongan Stream basin.

• Journal of Ecology and Environment
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• v.38 no.4
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• pp.397-403
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• 2015

Rice (Oryza sativa L.) is an important feeding crop in Asia, and utilization of genetically modified (GM) rice is highly demanding. For co-existence of GM rice and non-GM rice, the proper confinement measures should be provided. Thus, we surveyed gene flow from herbicide resistant GM rice to the conventional rice cultivars in the field tests. Gene flow frequency decreased with increasing distance between the pollen donor and recipients and did not exceed more than 1% even at the nearest distance. In single recipient model plot, a maximum gene flow frequency was observed at the shortest distance and hybrid was detected up to 12 m from the pollen donor. The direction of gene was coincided with the dominant wind direction. Gene flow assessment to multiple recipient plots was conducted under the high raining season by chance, and abrupt decline of gene flow frequency and maximum distance were resulted. According to the survey results, current regulation for isolation distance is reasonable for environmental safety or for general crop production. However, we suggest an alternative measure for GM rice cultivation that should be supplemented to overcome the out of estimation and in the environment asking higher security levels.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.579-587
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• 2017

Objective: The purpose of this study is to measure the workload of Korea coastal ship crew members, to investigate whether they are following work-break time regulations and to identify the main causes of their workload. Background: According to the US Coast Guard, about 33% of human casualties are reported to be due to fatigue, and 30% of marine casualties reported by the British Marine Accident Investigation Agency (MAIB) are attributed to crew fatigue. But the coastal ship are not managed for business hours and breaks despite the harsh environment. Method: The workload of duty crew members on the 100 domestic coastal vessels was measured. It was also investigated whether they are following domestic and international work-break time regulations. Finally, the marine accidents resulted from the fatigue of the crew was analyzed. Results: As a result of workload analysis, the workload on the 42~62% of the vessels exceeded the standard of working time on the related regulation. The workload increased with the number of inbound and outbound ports. Especially, in the system where there are two seafarers, the workload exceeded the working time requirement. As a result of the marine accidents analysis on 100 vessels, it was found that collision and grounding occurred due to fatigue, workload and drowsiness in 7 marine accidents out of 30 marine accidents. Conclusion: It is necessary for the shipping companies to introduce an operation management manual for the management of the crews' workload and reasonable crew arrangement. It is also required for crew members to easily record work times and for shipping companies to manage the record. It would be possible to prevent many marine accidents by providing adequate rest to the crews and flexibly adjusting their working hours. Application: The results of this study can be used as fundamental data to manage crews' fatigue and to make job management manuals.

• Journal of Auto-vehicle Safety Association
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• v.10 no.2
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• pp.43-49
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• 2018

Southeast Asia is a strategic market for both technology and inspection system to enter simultaneously. At the core market is Vietnam which is know to have the fourth highest registration of motorcycles as of 2016. The Motorcycle Inspection System is a social regulation, furthermore, the impact of the system is delivered through indirect means such as minimization of social cost. Therefore, measurements on the perception of users on the needs for an inspection system serves as valuable data to simultaneously enter this markets. This research is an empirical study on the perception of Vietnamese users on the needs to adopt a motorcycle inspection system based on data collected through surveys and is aimed at conducting a preliminary investigation on consumer behavior in Vietnam. The empirical study conducted through surveys revealed that Vietnamese motorcycle users perceive the needs for an inspection system for maintenance, safe operations and selling used vehicles at a reasonable price. In addition, the study also verified that the safe operations factor has a moderating effect due to interaction between prevention of illegal vehicle and reduction of emission gases. This research results present implications in developing equipment adapted to the local area in order to enter into a strategic market. Moreover, it is expected that the findings will also serve as valuable data for bilateral cooperation between the two countries and the diffusion of technology.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.5_2
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• pp.163-175
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• 2010

This study is based on the viewing characteristics of mountain landscapes. It investigates whether the current landscape management-related regulations are efficient in terms of the viewing characteristics of the mountain landscape against Bukhansan Mountain in which the conventional landscape management techniques were used. In addition, some viewing characteristics of mountain landscapes, such as distance from the view point to the target mountain, angle of elevation, altitude, gradient, have been analyzed and 3 cases of viewing condition have been simulated. The following results were obtained: i) Mountain landscapes can be managed up to 7~8 times of the mountain height with a $5{\sim}9^{\circ}$ of elevation angle. ii) In the Natural Landscape District which is situated on the hillside, it is reasonable to include altitude, gradient as criteria for regulation. iii) According to a simulation of the construction permit height by viewing distance, it was confirmed that buildings can be constructed up to 111.55m when viewing the 20% ridge, 150.75m when viewing the 50% ridge and 189.05m when viewing the 70% ridge. iv) The construction permit height varies depending on the landscape analysis method that is used and the application conditions. It is therefore unfair to apply height limit regulations to all buildings without considering the geographical features or viewing characteristics. v) It is unreasonable to apply 2~3 management techniques to the same area for landscape management. Therefore, we recommend the Focused Landscape Management Area based on the landscape master plan as a integrating mountain landscape management techniques.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.67
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• pp.209-231
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• 2015

The accurate national trade statistics can show the real nation's trade situation, and contribute to setting up the national's trade plans and corporate's strategies. This study researches the differences between trade statistics and actual trade record among the national and international statistics and suggests improvement plans to solve the problems. There are 4 types' differences among the trade statistics as follows; First, a statistical differences between Korea Customs Service and Bank of Korea by yearly US$9.6billions because of standard and boundary of trade statistics. Second, a statistical differences between Ministry of Trade, Industry and Energy and Korea Customs Service because of the time and purpose of trade statistics release. Third, a statistical differences between Korea and counterpart countries because of standard of trade statistics, intermediate countries and rules of origin. Lastly, a statistical differences between nation's statistics and corporate record because of typing errors and indirect export record. The fundamental improvement plans are Korea statistics rules like Korea Foreign Trade Rules and Korea Custom Rules, need to coincide with the international rules like IMTS, MSITS, BPM6 etc. Especially the rules of statistics related to intermediary trade, processing trade and transit trade have to revise with new BPM6 rules. In addition, a reasonable care of trade statistics from accumulation to utilization of trade information is more important than statistical regulation or system, so all persons concerned including exporters, importers, government official pay attention the statistics and cooperate together.