• Journal of The Korean Association of Information Education
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• v.20 no.6
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• pp.617-628
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• 2016

For the education on information, information appliances and operating systems of the information curriculum in elementary schools, precedent studies on the content structure of domestic and foreign curricula and etc. were compared and analyzed, and the ways of improvement and implications were examined. In addition, the necessity to select these contents, time of education, appropriateness of the selected contents were surveyed by professionals, and as the research results, the contents for the education on information, information appliances and operating systems in elementary schools were chosen, and achievement standards were set and proposed. The paper results can be used for the development of national level of elementary information curriculum and for the cultivation of elementary school students' key educational capacities. This paper has the limit that its results cannot be generalized because its analysis was based on the outcome surveyed only by some experts. Nevertheless, it is meaningful in that it specifically tried to analyze the appropriateness of the content achievement standards of the elementary information curriculum, and through which, it offers the information necessary for the stable management of elementary information curriculum and the improvement of elementary information curriculum.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.9
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• pp.727-734
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• 2015

Recently, because of the increased oil prices globally, there have been studies investigating the improvement of fuel-conversion efficiency in internal combustion engines. The improvements realized in thermal efficiency using lean combustion are essential because they enable us to realize higher thermal efficiency in gasoline engines because lean combustion leads to an increase in the heat-capacity ratio and a reduction of the combustion temperature. Gasoline direct injection (GDI) engines enable lean combustion by injecting fuel directly into the cylinder and controlling the combustion parameters precisely. However, the extension of the flammability limit and the stabilization of lean combustion are required for the commercialization of GDI engines. The reduction characteristics of three-way catalysts (TWC) for lean combustion engines are somewhat limited owing to the high excess air ratio and low exhaust gas temperature. Therefore, in the present study, we assess the reaction of exhaust gases and their production in terms of the development of efficient TWCs for lean-burn GDI engines at 2000 rpm / BMEP 2 bar operating conditions, which are frequently used when evaluating the fuel consumption in passenger vehicles. At the lean-combustion operating point, $NO_2$ was produced during combustion and the ratio of $NO_2$ increased, while that of $N_2O$ decreased as the excess air ratio increased.

• Journal of Energy Engineering
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• v.11 no.2
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• pp.114-121
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• 2002

Alkali metal compounds existed in original coal or sorbents are exhausted as vapor or small particle at the outlet of combustor when operating PFBC power plant. These compounds can be removed with dust removal equipment, but total generation efficiency will be decreased because of lower operating temperature of dust removal equipment. Alkali metal contained in vapor phase is initially deposited onto turbine blade results in serious corrosion. The concentration of alkali vapor in the PFBC flue gas is 20∼40 ppm which is dependent on mineral characteristics and composition as well as operating condition of PFBC. However, the allowance limit of alkali metal vapor is assigned as less than 50 ppb for gas turbine when coal or oil is used as fuel. Therefore, alkali metal vapor in PFBC or IGCC process should be removed by solid sorbents to prevent corrosion of turbine blade and improve plant efficiency. In the present investigation, powder of Bauxite, Kaolinite and Limestone is used in the preparation of cylinder-type pellet which is inserted into the pressurized alkali removal reactor for the alkali absorption experiment. Experimental results showed that the alkali removal efficiency in the order of Bauxite, Kaolinite and Limestone. Alkali vapor removal efficiency is related with reaction temperature, porosity of pellet and alkali vapor concentration of flue gas.

• Journal of the Korean Society of Safety
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• v.32 no.2
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• pp.132-146
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• 2017

Appropriate speed limits at a reasonable level in urban roads are highly important factors for efficient and safe movement. Thus, it is greatly necessary to develop the objective models or methodology based on engineering study considering factors such as traffic accident rates, roadside development levels, and roadway geometry characteristics etc. The purpose of this study is to develop the estimate model of appropriate speed limits at each road sections in urban roads using traffic information big data and field specific data and to review the effects of accident decrease. In this study, the estimate method of appropriate speed limits in directional two or more lanes of urban roads is reflecting features of actual variables in a form of adjustment factor on the basis of the maximum statutory speed limits. As a result of investigating and testing influential variables, the main variables to affect the operating speed are the function of road, the existence of median, the width of lane, the number of traffic entrance/exit path and the number of traffic signal or nonsignal at intersection and crosswalk. As a result of testing this model, when the differences are bigger between the real operating speed and the recommended speed limits using model developed in this study, the accident rate generally turns out to be higher. In case of using the model proposed in this study, it means accident rate can be lower. When the result of this study is applied, the speed limits of directional two or more lane roads in Seoul appears about 11km/h lower than the current speed limits. The decrease of average operating speed caused by the decrease of speed limits is 2.8km/h, and the decrease effect of whole accidents according to the decrease of speed is 18% at research road. In case that accident severity is considered, the accident decrease effects are expected to 17~24% in fatalities, 11~17% in seriously injured road user, 6~9% in slightly injured road user, 5~6% in property damage only accidents.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.4
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• pp.399-404
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• 2021

From 1 January 2020, the limit for Sulphur in fuel oil used on board ships operating outside designated emission control areas will be reduced to 0.5 %. This regulation by international maritime organization (IMO) is able to significantly reduce the amount of Sulphur oxides (SOx) discharging from ships and should have environmental advantages and health for all over the world. To meet the regulation, in these days, wet scrubber system is being actively developed. However, this process leads to make washing wastewater. In this study, we evaluated ion exchange resin system in accordance with scrubber wastewater discharge regulation by IMO. Theoretical wastewater used as feed solution of lab scale water treatment systems. The results revealed that nitrate ion was removed selectively in spite of high TDS wash wastewater solution depending on ion exchange resin property. Moreover, it was possible to improve efficiency of the system by optimizing operating conditions.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.1
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• pp.107-120
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• 2019

The decommissioning of one nuclear power plant in a multi-unit nuclear power plant (multi-unit NPP) site may pose radiation exposure risk to decommissioning workers. Thus, it is essentially required to evaluate the exposure dose of decommissioning workers of operating multi-unit NPPs nearby. The ENDOS program is a dose evaluation code developed by the Korea Atomic Energy Research Institute (KAERI). As two sub-programs of ENDOS, ENDOS-ATM to anticipate atmospheric transport and ENDOS-G to calculate exposure dose by gaseous radioactive effluents are used in this study. As a result, the annual maximum individual dose for decommissioning workers is estimated to be $2.31{\times}10^{-3}mSv{\cdot}y^{-1}$, which is insignificant compared with the effective dose limit of $1mSv{\cdot}y^{-1}$ for the public. Although it is revealed that the exposure dose of operating multi-unit NPPs does not result in a significant impact on decommissioning workers, closer examination of the effect of additional exposure due to actual demolition work is required. The calculation method of this study is expected to be utilized in the future for planned decommissioning projects in Korea. Because domestic NPPs are located in multi-unit sites, similar situations may occur.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.1
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• pp.13-24
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• 2021

Tunnel boring machine (TBM) is widely used for tunnel excavation in hard rock and soft ground. In the perspective of TBM-based tunneling, one of the main challenges is to drive the machine optimally according to varying geological conditions, which could significantly lead to saving highly expensive costs by reducing the total operation time. Generally, drilling investigations are conducted to survey the geological ground before the TBM tunneling. However, it is difficult to provide the precise ground information over the whole tunnel path to operators because it acquires insufficient samples around the path sparsely and irregularly. To overcome this issue, in this study, we proposed a geological type classification system using the TBM operating data recorded in a 5 s sampling rate. We first categorized the various geological conditions (here, we limit to granite) as three geological types (i.e., rock, soil, and mixed type). Then, we applied the preprocessing methods including outlier rejection, normalization, and extracting input features, etc. We adopted a deep neural network (DNN), which has 6 hidden layers, to classify the geological types based on TBM operating data. We evaluated the classification system using the 10-fold cross-validation. Average classification accuracy presents the 75.4% (here, the total number of data were 388,639 samples). Our experimental results still need to improve accuracy but show that geology information classification technique based on TBM operating data could be utilized in the real environment to complement the sparse ground information.

• Journal of the Korean Geosynthetics Society
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• v.22 no.2
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• pp.35-45
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• 2023

In accordance with the urban development project, cases of constructing temporary wall structures for ground excavation in the vicinity of railway structures are increasing. In addition, the complaints about train vibration are also increasing from people living in large buildings newly built after installing the temporary wall structures. In order to solve this problem, a method for reducing train vibration is considered from the design stage of the building, and a vibration reduction system is installed on the structure when the building is newly constructed. However, the vibration reduction method established at the structure design stage can be determined through the results of field measurements or dynamic numerical analysis for a specific area, and there is a limit to evaluating whether the established vibration reduction method is appropriate due to the lack of objective research data. Therefore, in order to provide objective basic data when establishing a vibration reduction method, this study performed the dynamic numerical analysis for a operating train with a speed 80km/h by applying differently the depths of railway structures, the distances between railways and temporary wall structures, and ground conditions. It was found that the range of influence of a train operating at 80 km/h was within 4.5D of the lateral distance from the railway structure in the case of the condition where the temporary wall was installed.

• The Korean Society of Law and Medicine
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• v.22 no.2
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• pp.111-138
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• 2021

'Unlicensed medical practice by a non-medical practitioner' often represented by surrogate surgery or so-called 'ghost surgery,' causes irreparable damage to life or body, and therefore calls for very strict and effective controls. The 'bill on installment of CCTVs in an operating room' to prevent unlicensed surrogate surgery has been discussed for a long time, but due to numerous issues and heated confrontations, it has been pending in the National Assembly. Nevertheless, it is expected that the bill will be discussed again in earnest in the National Assembly because surrogate surgery and factory-type cosmetic surgery, which has been performed mainly in the field of cosmetic surgery, has also been occurring in the field of therapeutic surgery. In general, an operating room is considered as being locked or closed, as well as disallowing implicit complicity among insiders. Hence, if the insiders conspire to commit or cover up an illegal act, or if a surgeon performs rapid cosmetic surgery and then leaves the recipient (or medical institution) so as to perform more operations for profit - even if it is legitimate practice - it may result in serious consequences in terms of the recovery of a patient. In this case, installation of CCTVs can be of great help in identifying an illegal act and assessing any occurrence of negligence. On the other hand, while the fundamental purpose of therapeutic surgery is to restore a patient's life or body - that is, lifesaving - installation of CCTVs may base the relationship between a surgeon and a patient on distrust and surveillance, so it may increase the number of requests for CCTV footage or lead to more disputes, as well as placing a burden on the surgeon when best results are not achieved for a patient. As a result, the surgeon may choose non-invasive treatment contrary to conscience instead of risky but necessary surgery, or he/she may have significant difficulty in determining the timing of surgery, which may limit the provision of effective surgical medical care. Then, in terms of the relationship between a surgeon and patient, and in the long run, there could be significant disadvantages for the public and patients if CCTV footage is allowed. In this paper, we review domestic and overseas cases and issues regarding installation of CCTVs in an operating room, and present various viewpoints and suggestions to promote legislation with minimized legal problems and side effects, thereby contributing to protection of the lives and health of the public, patients, and recipients of surgery.

• The Korean Journal of Air & Space Law and Policy
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• v.28 no.1
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• pp.55-71
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• 2013

By aircraft from Aviation regulations and institutional regulatory framework for ensuring the safety is secured. State-of-the-art aircraft, according to the type of development and diversification, modernization and new types of aircraft are operated. In particular, light aircraft and ultralight flying device such as the gyro-plane and unmanned flying devices is introduced a new device, and the device operates at these flight in accordance with the standards of the Aviation Act regulations may not occur often. Variety of light aircraft and ultra-light aircraft assembly, can be adapted for a person engaged in the business of aviation safety management and to perform the legal basis was established. Depending on the classification of newly introduced aircraft, the biggest change is the introduction of the concept of the LSA. In Korea, the various light aircraft are operating, but these aircraft range not clearly Aviation Regulations had difficulty in ensuring safety. This study examined the differences between international rules and regulations of Korea about the classification of aircraft. The LSA are included in aircraft categories internationally, but LSA will not be included in the aircraft categories, which is one of a range of powered flight device exists in Korea Aviation Act. Limit for maximum continuous power speed in a LSA, it is a limit on the right of the people who want using the high-performance plane. Also it is an international trend does not fit in, and is consistent with the intent of LSA manufacturer. Delete the content from a range of future aviation law revisions and light aircraft-related provisions to limit the maximum continuous power speed is considered to be suitable for the purpose of introducing the light aircraft industry. The laws and regulations set up in order to ensure the safety of ultralight aircraft categories existing in ultralight aircraft that exceeds the purpose of the introduction of LSA technology development at home and abroad, and is intended to reflect. These standards complement of aircraft operation is not appropriate for the situation unless the country is difficult to ensure the safety of operations. Also developed in other countries, the introduction of aircraft operating in the country, so many problems occur early revision is required.