• Journal of the Korean School Mathematics Society
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• v.13 no.1
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• pp.23-43
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• 2010

This study is to investigate how much highschool students, who have learned functional concepts included in the Middle school math curriculum, understand chapters of the function, to analyze the types of errors which they made in solving the mathematical problems and to look for the proper instructional program to prevent or minimize those ones. On the basis of the result of the above examination, it suggests a classification model for teaching-learning methods and teaching material development The result of this study is as follows. First, Students didn't fully understand the fundamental concept of function and they had tendency to approach the mathematical problems relying on their memory. Second, students got accustomed to conventional math problems too much, so they couldn't distinguish new types of mathematical problems from them sometimes and did faulty reasoning in the problem solving process. Finally, it was very common for students to make errors on calculation and to make technical errors in recognizing mathematical symbols in the problem solving process. When students fully understood the mathematical concepts including a definition of function and learned procedural knowledge of them by themselves, they did not repeat the same errors. Also, explaining the functional concept with a graph related to the function did facilitate their understanding,

• Korean Journal of Construction Engineering and Management
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• v.16 no.1
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• pp.24-34
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• 2015

As recent multilateral collaboration design system has been advanced, BIM based data exchange is a key factor for successful next generation building project. Even though many studies have been trying to set up a data compatibility system for collaboration, There are still a lot of problem in data exchange between design and engineering phase. Therefore, In this study, we analysis causes of problem for information exchange and suggest a IFC based Information exchange framework for improving BIM based design collaboration environment. In order to find out problems that hinder establishment of advanced open BIM information exchange, proper analysis about transition of process from current and to-be BIM based design collaboration process is important, at first. From analysis of main obstacles to information exchange, this research suggests solution plan using open API and IFC based BIM collaboration supporting system. The suggested open API solution named Integrity feedback system perform a role making up for weak point derived from IFC based data exchange. And main system suggestion about framework for IFC based information exchange reflect technological system support, requirement of function for collaboration including API/BCF plug-in.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.2
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• pp.52-59
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• 2008

The objective of this study is to develop an automatic object changer unit to improve processing problems existed in the conventional horizontal machining center. To achieve this goal, this study designed a horizontal transfer as the second project continued to the first project that designed a upward and downward traverse unit. A horizontal traverse unit shows a symmetric structure and consists of frame, which consists of four unit tools, motor and reducer, which are fixed at a frame, operation unit with pinions, first traverse unit, and second traverse unit. Constraint conditions based on the operation mechanism with these elements were configured and obtained following results after modeling a model for a traverse motor. In the kinematic expression of sliding motion with one degree of freedom, the sliding motion is constrained. Also, the rack 3 installed at a frame is used to configure possible kinematic constraint conditions of the rack 2 according to the rolling motion of the pinion 2 in the first traverse unit. In addition, the moment of inertia that is a type of kinetic energy in a converted horizontal traverse unit in the side of the reducer can be applied to introduce the moment of inertia of a converted horizontal traverse unit in the side of the reducer by using the sum of kinetic energy in the rack and pinion, which is a part of the horizontal traverse unit. Also, the equation of motion of the converted upward and downward traverse unit in the side of the motor using the equation of motion of the motor. Furthermore, the horizontal traverse unit predetermines the mass of the first and second traverse unit and applied load including the radius and reduction ratio of the pitch circle in the pinion 1 and applied load to the rack 2. Then, a proper motor can be determined using several parameters in the upward and downward traverse unit in order to verify such predetermined specifications. In future studies later this study, a simulation that verifies the results of the previous two stages of studies using a finite element method.

• Journal of Korean Society of Rural Planning
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• v.20 no.4
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• pp.77-87
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• 2014

Ecotourism has the potential to boost the energy of a village as it pays keen attention to the ecosystem and the residents of the village. It is empowered by participation of and cooperation among stakeholders who are closely involved in ecotourism. However, many of them express difficulty in striking a right balance between development and conservation with regard to promoting ecotourism. Against this backdrop, this research paper investigates the structure of conflict that the stakeholders, especially those in Stork Village in Yesan County, South Chungcheong Province of Korea, experience during the process of establishment of government-led ecotourism. In addition, this study examines the problems of government-led ecotourism model and how they can be addressed. To analyze conflict structure, this paper used Q methods and found out that the budget-related stakeholders are largely divided into four groups as who; a) complain about how business profits are distributed; b) secure profits by expanding programs; c) consider human settlement, and; d) broaden people's participation. The biggest contributor to the conflicts is found that compensation was given discriminately to different jurisdictions. The second finding is that residents became less cooperative when the financial compensation did not live up to their expectation. For instance, they would demand the tourism facility physically expanded, repeatedly complain about the process of the work, and even accuse the government of degrading ecosystem. In other words, unless the compromise is reached with the residents regarding financial compensation, it could be difficult to encourage their participation and develop as a program-oriented tour. Lastly, the tour program needs to induce voluntary participation of the residents and deliver proper information on ecosystem and natural resources so as to last as sustainable ecotourism. The success of ecotourism will be subject to the cooperation of stakeholders in a region, conservation of our fragile ecosystem, and realization of sustainable growth through sharing economic benefits. This study looks into the cause of the conflicts of ecotourism sites and their structure. If this paper can bring about cooperation of stakeholders, the management and operation of ecotourism sites would be more sustainable.

• Korean Journal of Comparative Education
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• v.26 no.4
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• pp.173-198
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• 2016

The purpose of this study is to analyze the characteristics of Educational Reforms Policy in lately Japan and to evaluate it. Especially focus on the activities of the [MEXT; Ministry of Education, Culture, Sports, Science and Technology] and [CCE;The Central Council for Education] This article composed of five chapters; Implication and problem situation, History of the Japanese educational reforms, the characteristics in the site of process of educational reforms policy, evaluation on the main policies, and Conclusion(contain the suggestion for Korea). The method of study composed of the literature search and interview. The System Analysis[input-process-output-feedback] is used as a model of the analyze the characteristics of educational reforms policy. By the new Basic Act on Education, the principles of educational administration is changed. Education administration shall be carried out in a fair and proper manner through appropriate role sharing and cooperation between the national and local governments(Article 16). As a conclusion, The initiative in the establishment of educational reform plans has gone over to the cabinet side from MEXT. And evaluate the five policies. That is Japan's Basic Plan for the Promotion of Education, The new Basic Act on Education(enacted on 2006), Provincial Governor's (Tokyo & Oska) Educational Reform Plan, Reform plan of the Boards of Education, and Improvement Policy of the Quality of Teachers.

• Clean Technology
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• v.28 no.4
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• pp.316-322
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• 2022

The flow pattern at the inlet of the catalyst layer in a selective catalytic reduction (SCR) system is one of the key parameters influencing the performance of the denitrification process. In the curved diffusing parts between the ammonia injection grids and the catalyst layers, guide vanes are installed to improve flow uniformity. In the present study, a numerical simulation has been performed to investigate the effect of the geometrical configuration of the guide vanes on the aerodynamic characteristics of a denitrification facility. This application has been made to the existing SCR process in a large-scaled coal-fired power plant. The flow domain to be solved covers the whole region of the flow passages from the exit of the ammonia injection gun to the exit of the catalyst layers. ANSYS-Fluent was used to calculate the three-dimensional steady viscous flow fields with the proper turbulence model fitted to the flow characteristics. The root mean square of velocity and the pressure drop inside the flow passages were chosen as the key performance parameters. Four types of guides vanes were proposed to improve the flow quality compared to the current configuration. The numerical results showed that the type 4 configuration was the most effective at improving the aerodynamic performance in terms of flow uniformity and pressure loss.

• Journal of Convergence for Information Technology
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• v.12 no.3
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• pp.132-140
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• 2022

This study was conducted to identify the optimal lotion manufacturing conditions with decursin and decursinol angelate of Angelica gigas Nakai extraction. Lotion was confirmed that it had viscosity (5,208±112 cPs), assay (99.71±1.01%), and pH (5.62) for 3 months. The optimization of manufacturing conditions of mixing 4 for lotion formulation were made by 22+3 full factorial design. Mixing temperature (40-80℃) and mixing time (10-30 min) were used as independent variables with three responses(assay, pH, and weight variation) as critical quality attributes (CQAs). The model for assay and weight variation identified a proper fit having a determination coefficient of the regression equation (about 0.9) and a p-value less than 0.05. Estimated conditions for the optimal manufacturing process of lotion were 61.93℃ in mixing temperature and 15.85 min in mixing time. Predicted values at the mixing temperature (60℃) and mixing time (20 min) were 100.69% of assay, 5.57 of pH, and 98.07% of weight variation. In the verification of the actual measurement the obtained values showed 100.29±0.98% of assay, 5.57±0.02 of pH, and 98.27±0.89% of weight variation, respectively, in good agreement with predicted values.

• Journal of the Korea Institute of Building Construction
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• v.17 no.2
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• pp.191-197
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• 2017

The safety nature of construction industry differs from that of manufacturing sector. For instance, accident risk level dramatically varies at each phase of construction process. Korean Occupational and Health Safety Act has been regulated OHS expense and it contributed reducing accident risk and enhancing safety culture for many years. However, although current regulation guides to use OHS expense proportionate to construction progress, it still allows late use of the expense. This study was conducted for the purpose of presenting methods of estimating a step-by-step OHS expense rate required at each construction phase. In order to do provide proper OHS expense schedule, it analysed accident risk of each construction phase by sorting out 1439 cases of construction site fatality reports, and proposed a method of generating appropriate OHS expense scheme according to its construction work progress characteristics. Both linear and sigmoidal S-curve model were used for the analysis, and the latter generally requires earlier use of OHS expense. By comparing the estimated OHS expense use schedule with current criteria, more than 27%p early use of OHS expense is required for the prevention of accident.

• Korean Journal of Construction Engineering and Management
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• v.16 no.4
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• pp.118-128
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• 2015

Recently BIM technology has been expanded for using in construction project. Due to the high-cost of BIM infrastructure development, lack of regulations, lack of process and so forth, usage of BIM has been delayed than initial expectations. In design phase, especially, collaboration based on BIM system has been a key factor for successful next generation building project. Through the analysis of current research trends about IT technologies, virtualization and BIM service, data exchange such as drawings, 3D model, object data, properties using cloud computing and virtual server system is defined as a most successful solution. The purpose of this study is to enable the cloud computing BIM server to provide several main functions such as editing models, 3D model viewing and checking, mark-up and snapshot in high-performance quality by proper design of VDI system. Concurrent client connection performance is a main technical index of VDI. Through testing of test-bed server client, developed VDI system's multi-connect control is evaluated. Performance-test result of BIM server VDI effect to development direction of cloud computing BIM service for commercialization.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.855-861
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• 2009

This paper presents the concept of dynamically reconfigurable space by introducing smart building components. Thanks to the advances in ubiquitous computing and ITC technology, we are able to expect, in the near future, the aspects of future buildings which may transform their appearance and states to perform specific functions. In other words, it is certain that the building space will actively reconfigure itself to accommodate user's needs once we acquire proper technologies. Based on the assumption that building components may not be transformed through the magical process, but change its physical states (e.g. transparency, illumination, display contents, etc.) and functions of embedded devices (e.g. audio, actuators, sensors, etc.), we can envision a dynamically reconfigurable smart space. In order to conceptualize such spaces, critical surveys have been conducted on current works of leading architects. When the room needs to be used as a specific function room, the components need to change theirs states or to behave in a certain manner to create an optimum environment. Our model defines the relationships and elements to describe the mechanism of reconfigurable space. We expect this model provides a conceptual guideline for developing a smart building components based on spatial service scenarios. Therefore, a future smart spaces implemented by integrating various technologies are not designed in deterministic manner, so that spatial functions are expanded without constrained by physical existence.