• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.4
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• pp.395-406
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• 2023

The first technological advance to improve the output and efficiency of the latest steam turbines operating in co-generation plants in Korea can be said to be progress in the field of materials that can use high-temperature, high-pressures steam. As a result of design efforts to improve the internal efficiency of steam turbines along with the development of materials, only a few manufacturers of steam turbine have produced high efficiency steam turbines. The internal efficiency of a steam turbine on the steam path operating for a long period of time is gradually lost owing to the limit of mechanical life, and efficiency and output decrease. Therefore, this study aims to develop a model that can analyze the steam flow path performance of HP (High Pressure) and IP (Intermediate Pressure) steam turbine for a co-generation plant using a commercial program and propose a performance calculation method. Owing to the complex performance calculation method of steam turbines, major variables are presented to serve as practically useful references for steam turbine practitioners. In addition, the thermal dynamic analysis(such as heat balance diagram calculation) and the the thermal dynamic calculation required for steam turbine performance calculation and the suitability of the steam turbine performance calculation results were compared with the performance test results.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.3
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• pp.29-43
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• 2012

This study evaluated 23 botanic gardens and arboretums under two main categories including professional group and operational group. As for professional group, the main difference between the functions of botanic gardens and arboretums was analyzed. In the case of operational group compared professional group respectively, on categories including importance of function and implementation, seeking to provide fundamental data of botanic gardens and arboretums by enhancing the quality of visitors and examining functional differences. The result of a difference in arboretums' function between professional and operational groups, the study analyzed the importance of botanic gardens and arboretums in terms of detailed categories such as research, education, collection, display, retention, and service for visitors. As a result, professional group showed retention 4.32>education 4.11>research 4.09>service for visitors 4.05, and operational group showed retention 3.70>service 3.52>education 3.41>research 3.37, indicating that both groups had retention as the most selected answer. Looking closely at the functions of the currently implemented detailed categories of botanic gardens and arboretums, such as research, education, collection, display, retention, and service for visitors, the study showed that 91.3% selected rare species and individual multiplication for research function, 78.3% chose education of natural ecosystem for children for education, 73.9% answered space for experiencing nature for display, and 73.9% also replied managon, diof rare species, reproduction, and retention of native plants' species for retention category, and service for visitors showed 95.7% for implementation. The study could not clearly point out the influence between predictors due to absence of an established comprehensive evaluation model. Also, it analyzed and reviewed comparison of functions of professional group and operational group, but in the future, it should conduct study on a systemic and objective classification of botanic gardens and arboretums to clearly examine the difference in views between groups, which also requires, at the same time, study on management policy of botanic gardens and arboretums or suggesting guidelines that suit types of forms, and also study on facilities and program development that can be applied to each class.

• Journal of radiological science and technology
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• v.36 no.2
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• pp.99-110
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• 2013

In the medical field, the necessity of education growth for the professional Radiation Technologists has been emphasized to become experts on radiation and the radiation field is important of the society. Also, in hospitals and companies, important on thesis is getting higher in order to active and cope with rapidly changing internal and external environment and a more in-depth expert training, the necessity of new teaching and learning model that can cope with changes in a more proactive has become. Thesis writing classes brought limits to the in-depth learning as to start a semester and rely on only specific programs besides, inevitable on passive participation. In addition, it does not have a variety opportunity to present, an actual opportunity that can be written and discussed does not provide much caused by instructor-led classes. As well as, it has had a direct impact on the quality of the thesis, furthermore, having the opportunity to participate in various conferences showed the limitations. In order to solve these problems, in this study, writing thesis has organized training operations as a consistent gradual deepening of learning, at the same time, the operational idea was proposed based on the connectivity integrated operating and effective training program & instructional tool for improving the ability to perform the written actual thesis. The development of teaching and learning model consisted of 4 system modeling, scaffolding, articulation, exploration. Depending on the nature of the course, consisting team following the personal interest and the topic allow for connection subject, based on this, promote research capacity through a step-by-step evaluation and feedback and, fundamentally strengthen problem-solving skills through the journal studies, help not only solving the real-time problem by taking wiki-space but also efficient use of time, increase the quality of the thesis by activating cooperation through mentoring, as a result, it was to promote a positive partnership with the academic. Support system in three stages planning subject, progress & writing, writing thesis & presentation and based on cognitive apprenticeship. The ongoing Coaching and Reflection of professor and expert was applied in order to maintain these activities smoothly. The results of this study will introduce actively, voluntarily and substantially join to learners, by doing so, culture the enhancement of creativity, originality and the ability to co-work and by enhance the expertise of based-knowledge, it is considered to be help to improve the comprehensive ability.

• Analytical Science and Technology
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• v.5 no.4
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• pp.349-358
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• 1992

The direct determination of lead in the whole-blood by graphite furnace atomic absorption spectrometric analysis was carried out by using the sample which was diluted five-fold with 1% Triton X-100. Matrix modification was tried to remove the interferences of blood matrix and also to get the optimum analytical condition. Good agreement with certificated values in reference materials(bovine blood) supplied by comparison program in Japan was obstained when 1% $(NH_4)_2HPO_4$ as matrix modifier and ashing temperature, $700^{\circ}C$ were used or 1% $(NH_4)_2HPO_4$ and 0.1% $PdCl_2$ as matrix modifier and ashed at $700^{\circ}C$. Standard deviations were appeared as 2.2~6.3% for 1% $(NH_4)_2HPO_4$ and 3.1~9.1% for 1% $(NH_4)_2HPO_4$ and 0.1% $PdCl_2$ in the range of $31{\sim}624{\mu}gPb/l$.

• Journal of Nutrition and Health
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• v.39 no.7
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• pp.684-691
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• 2006

Abdominal obesity (AO) is a strong risk factor for type 2 diabetes and cardiovascular disease, which has shown a remarkable increase in Korea. This study aimed to identify prevalence of AO and related risk factors in Korean adults. A total of 5,132 men and women aged 20-85 years old from the 2001 Korean National Health and Nutrition Examination Survey were included in the analyses. AO was defined as waist circumference >=90 cm in men and >=85 cm in women as proposed by Korean Society of Obesity. Multiple logistic regression was carried out to identify risk factors for AO. Three models were specified: (i) demographic and socioeconomic factors (model 1: age, education, poverty income ratio, employment), (ii) lifestyle factors and covariates (model 2: physical activity, cigarette smoking, alcohol consumption, dietary quality, type 2 diabetes, co-morbidity) and (iii) demographic, socioeconomic and lifestyle factors (model 3). The prevalence of AO was 24.1 % in men, 23.5% in women. High poverty income ratio in men and low education attainment in women were risk factors for AO in model. 1. There was a significant association of AO with alcohol consumption, physical inactivity and dietary quality in men, alcohol consumption and cigarette smoking in women. These factors except alcohol consumption in men became insignificant in model 3. This findings underscore the importance of developing AO prevention programs in Korea that target the at risk groups identified in this study. A program focusing on low income men or less educated women would be more efficient.

• KIEAE Journal
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• v.17 no.4
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• pp.67-74
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• 2017

Purpose: As the recent climate environment changes so rapidly, environmental problems such as hot weather and fine dust have occurred, and interest in environmental policies and technology development is increasing in countries around the world. Similarly in the Architecture, researches to reduce greenhouse gas emissions and to reduce energy application are actively conducted. Looking at previous studies, it is analyzed that the electric VRF is more energy efficient than the gas engine VRF. However, energy costs have changed due to recent price hikes and discounts on gas charges due to high electricity consumption in summer. Method: In this study, the actual building of Gas Engine VRF system was modeled using SketchUp program, and EnergyPlus was used to simulate actual building. Also, Electric VRF system was simulated, and compared with Gas Engine VRF system. Result: The total secondary energy requirement of Electric VRF system was 19.6% less than that of the Gas Engine VRF system, But when analyzing with primary energy requirement, EHP used 15.8% more energy. CO2 emissions were also estimated to be 16.9% more EHP. Energy costs were 14.8% more in Electric VRF systems, because their electricity charges are 0.6 to 160% more expensive than gas charges.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.1-8
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• 2017

Recently, the development of the head mounted display (HMD) device has attracted a great deal of attention to the actual contents. Especially, Augmented Reality (AR), which is a mixture of actual information and virtual world information, is focused on. AR HMD is able to interact by arranging virtual objects in real space through spatial recognition using depth camera. In order to naturally mix virtual space with real space, it is necessary to develop a technology for realizing spatial mapping information with high accuracy. The purpose of this paper is to evaluate the optimal configuration of augmented reality application program by realizing accurate spatial mapping information when mapping a real space and an object placement environment using HoloLens. To do this, we changed the spatial mapping information in real space to three levels, which are the number of meshes used in cubic meters to scan step by step. After that, it was compared with the 3D model obtained by changing the actual space and mesh number. Experimental result shows that the higher the number of meshes used in cubic meters, the higher the accuracy between real space and spatial mapping. This paper is expected to be applied to augmented reality application programs that require scanning of highly mapped spatial mapping information.

• Journal of the Korea Society of Computer and Information
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• v.18 no.5
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• pp.9-17
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• 2013

This paper presents the design of the educational router system. This system is designed and implemented to support network configuration and embedded programming technology of the user on Internet. Not only Static routing protocol but also a kind of dynamic routing protocols such as OSPF and RIP and firewall have been programmed for education based on ethernet interface. ADS 1.2 as debugging environment, uC/OS-ii as RTOS and C language as development language are used. The educational procedures is compile, loading of static routing protocol, a kind of dynamic routing protocols such as OSPF and RIP and firewall program already supplied. Thereafter the verification is checked by using "ping" test to allow for demo operation such as hands-on training procedure. Finally programming procedure similar with demo operation of static routing protocol, a kind of dynamic routing protocols such as OSPF and RIP and packet filtering function is educated step by step.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.452-460
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• 2014

Due to increased concerns for rising oil prices and environmental problems, various solutions have been proposed for solving energy problems through tightening environmental regulations such as those regarding $CO_2$ reduction. Among them, Electrical Vehicles (EVs) are evaluated to be the most realistic and effective approach. Accordingly, research and development on EVs and charging infrastructures are mainly proceeding in developed countries. Since EVs operate using electric energy form a battery, they must be connected to the power system to charge the battery. If many EVs are connected during a short time, power quality problems can occur such as voltage sag, voltage unbalance and harmonics which are generated from power electronics devices. Therefore, when EVs are charged, it is necessary to analyze the effect of power quality on the distribution system, because EVs will gradually replace gasoline vehicles, and the number of EVs will be increased. In this paper, a battery for EVs and a PWM converter are modeled using an ElectroMagnetic Transient Program (EMTP). The voltage sag and unbalance are evaluated when EVs are connected to the distribution system of the Korea Electric Power Corporation (KEPCO). The simulation results are compared with IEEE standards.

• Journal of the Korean GEO-environmental Society
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• v.20 no.1
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• pp.35-42
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• 2019

Various development works inevitably increase cutting slopes due to land use, and many of trails managed by different authorities are being deteriorated by long-term weathering. Collapse of slopes causes unavoidable damage of property and loss of lives because of its uncertainty and difficulty in predicting its occurrence. In order to overcome the unavoidability, America, Japan, and several European nations analyze the kinetic energy and moving distance when rocks of upper slope move along the inclined plane, via field tests and computerized interpretation of the test results. Also, they are making efforts to develop measures with which the kinetic energy of the rocks moving along the slope is absorbed and fails to reach to specific structures. However, domestic researches just focus on fragmentary prediction of rockfall using existing programs, and there have been few approaches to identify interpretation methods appropriate for domestic cases or determination of parameters. In this context, we in this study defined rockfall types and affecting factors and analyzed effects of parameters using a general-purpose rockfall simulation program to understand principles of rockfall and to estimate effects of various parameters.