• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1285-1292
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• 2011

The characteristics of a semiconductor chiller system with EEV have been experimentally studied. Three experiments on temperature changes (increase and decrease), load variation, and control precision were conducted to investigate the operating characteristics of the semiconductor chiller. The power consumption was 8.9 kW during increase in temperature. The required time was 37.5 min for CH1 and 39.5 min for CH2. Moreover, the time required for falling temperature was 26.5 min. The control precision for partial load operation was relatively low compared to that of a full load operation. In addition, the CH2 equipped with a step motor showed better control precision. The power consumed by the chiller for process cooling water was 1.8 kW, which was one-half of that consumed during the refrigeration cycle. The objective of this study is to provide an optimal control guideline for the semiconductor chiller design.

• Journal of Korean Society of Rural Planning
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• v.23 no.3
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• pp.163-174
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• 2017

This study developed the prototype of the system and implemented its main functions, which is the intelligent integrated agricultural water management information system and service (IaWAMISS). The developed system was designed to be able to collect, process and analyze the agricultural water information of spatially dispersed reservoirs in whole country and spatial geographic information distributed in various systems of other organizations. The system, IaWAMISS, is also possible to provide the reproduced information services in each reservoir and space units, such as agricultural water demand and supply analysis and drought prediction, to the people, experts, and policy makers. This study defined the 6 step modules to develop the system, which are to design the components of intelligent integrated information system, to derive the utilization contents of existing systems, to design the new development elements for IaWAMISS, to design the reservoir information system can be used by managers of city and county, to designate the monitoring reservoirs managed by city and county, and finally to prepare the sharing system between organizations with the existing information systems. In order to implement the prototype of the system, this study shows the results for three important functions of the system: spatial integration of reservoirs' information, data link integration between the existing systems, and intelligent analysis program development to assist decision support for agricultural water management. For the spatial integration with the reservoir water information of the Korea Rural Community Corporation, this study get IaWAMISS to receive the real-time reservoir storage information from the measurement facility installed in the municipal management reservoir. The data link integration connecting databases of the existing systems, was implemented by integrating the meteorological information of the Korea Meteorological Administration with IaWAMISS, so that the rainfall forecast data could be derived and used. For the implementation of the intelligent analysis program, this study also showed the results of analysis and prediction of agricultural water demand and supply amount, estimation of Palmer drought index, analysis of flood risk area in typhoon course region, and analysis of the storage status of reservoirs related to each storm. This study confirmed the possibility and efficiency of an useful system development through the prototype design and implementation of IaWAMISS. By solving the preliminary 6 step modules presented in this study, it is possible not only to efficiently manage water by spatial unit, but also to provide the service of information and to enhance the relevant policy and national understanding to the people.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.1
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• pp.39-45
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• 2012

Three-dimensional integrated circuit(3D IC) technology has become increasingly important due to the demand for high system performance and functionality. In this work, BOE and HF wet etching of Cu line surfaces after CMP were conducted for Cu-Cu pattern direct bonding. Step height of Cu and $SiO_2$ as well as Cu dishing after Cu CMP were analyzed by the 3D-Profiler. Step height increased and Cu dishing decreased with increasing BOE and HF wet etching times. XPS analysis of Cu surface revealed that Cu surface oxide layer was partially removed by BOE and HF wet etching treatment. BOE treatment showed not only the effective $SiO_2$ etching but also reduced dishing and Cu surface oxide rather than HF treatment, which can be used as an meaningful process data for reliable Cu-Cu pattern bonding characteristics.

• Journal of the Korean Chemical Society
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• v.32 no.3
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• pp.233-242
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• 1988

The uranium(VI) complexes with new unsaturated macrocyclic ligands of cryptand types and the neodymium(III) complexes with cryptand 222 and DBC ligands have been investigated polarographically in dimethylsulfoxide solvent. The reduction states, electron numbers involved in the reduction process, effects of the added acid on the polarograms of complexes, and the mechanisms of the reduction electrode reactions have been examined. The stability constants and mole-ratio of new complexes were also obtained by polarographic method. The reaction of ligands was controlled by the diffusion in the reduction with four electrons at a step, whereas the redox reaction with six electrons at three steps in $UO_2\;^{2+}$ complexes with macrocyclic ligands and the redox reaction with one electron at a step in $Nd^{3+}$ complexes with cryptand 222 and DBC have been observed. The imine ligands formed stable complexes with uranium(VI) above pH 7.0, and the neodymium(III) complexes with cryptand 222 and DBC ligands were stable above pH 4.0.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.652-656
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• 2018

In this study, effects of the reaction pressure were studied for petroleum-based pitch synthesis. A two-stage reaction process was performed based on different reaction pressure conditions. Each stage experiments for the two-stage reaction were consecutively carried out. The first stage was consisted of three different pressure conditions; high (10 bar), normal and low (0.1 bar). And the second stage was carried out at the normal and low (0.1 bar) pressure. The pitch synthesis was realized at $400^{\circ}C$ for 2 h. Thermal properties and molecular weight distributions of each samples were investigated by analyzing the softening point and MALDI-TOF data. Volatilized components during the pith synthesis were measured by GC-SIMDIS. In case of the first-step reaction with the high pressure condition, the low molecular weight component participated to the pitch formation more effectively and the pitch with the low softening point was obtained. However, for the case of the first-step with the low pressure, the low molecular weight component was vent outside and the partial coke formation occurred. Eventually, pitch properties such as the softening point and yield were controlled effectively by changing the pressure in the pitch synthesis reaction.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.31-37
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• 2021

As the size of buildings increases due to urbanization due to the development of industry, the need to purify the air and maintain a comfortable indoor environment is also increasing. With the development of monitoring technology for refrigeration systems, it has become possible to manage the amount of electricity consumed in buildings. In particular, refrigeration systems account for about 40% of power consumption in commercial buildings. Therefore, in order to develop the refrigeration system failure diagnosis algorithm in this study, the purpose of this study was to understand the structure of the refrigeration system, collect and analyze data generated during the operation of the refrigeration system, and quickly detect and classify failure situations with various types and severity . In particular, in order to improve the classification accuracy of failure types that are difficult to classify, a three-step diagnosis and classification algorithm was developed and proposed. A model based on SVM and LGBM was presented as a classification model suitable for each stage after a number of experiments and hyper-parameter optimization process. In this study, the characteristics affecting failure were preserved as much as possible, and all failure types, including refrigerant-related failures, which had been difficult in previous studies, were derived with excellent results.

• Journal of Korea Entertainment Industry Association
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• v.13 no.2
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• pp.1-12
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• 2019

Based on the capabilities of smartphone cameras which have developed rapidly in recent decades, coupled with and the global market penetration rate, it will study the possibility of various international exchanges through smartphone filmmaking. This aims to achieve a civilian-oriented cultural exchange, instead of simply providing capital-oriented exchanges and film production education. The Smartphone Film Workshop was held as an auxiliary event of the Korea-Vietnam Film Festival, which ran from November 17 to 22, 2017. The three-day workshop, which took place within the festival period, drew attention for its international collaboration project between Korean film directors and Vietnamese film students. The researcher conducted practical-based research while participating as a mentor at this workshop. A step-by-step approach to the entire process of production and post-production was administered, including workshop team composition, scenario, and pre-production in Korea such as shooting equipment, schedule, completion of local works, and screening. Through an analysis of exchange cases at international workshops, we will use trial and error as ways to improve and consider the results of cultural exchanges and the effects of future expectations. Taking this empirical case study into account, we anticipate more active international exchanges through the smartphone workshops.

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.357-366
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• 2023

In the purpose of this study, the college textbooks of self-narrative writing and examples of classroom practice are analyzed to find a way to educate it. The self- narrative writing subject with a learning of recognization, expression, and communication with oneself, emphasizes the necessity when they become college students through entrance exam-oriented education. The research methods are as follows. Firstly, three university textbooks which include a section on self-narrative writing were compared and analyzed. The analysis highlights the needs for a textbook covering self-narrative writing more extensively and comprehensively as what is offered by the existing textbooks is limited in facilitating students to fully develop the ability of self-reflection, which should be dealt as a long-term goal. Secondly, the current discussion on self-narrative writing and examples of real classroom practice were analyzed. It shows that a step-by-step approach is required to encourage the practice of deep self-reflection to be incorporated into writing. In addition, during the writing process, various correction and feedback activities should be carried out on a macro level and gradually while the communication and feedback should take place not only between a teacher and students, but also among students. As a result, it is expected that this study will help establish a teaching model of self-narrative writing by seeking complementary points and educational directions for self-narrative writing.

• Hwankyungkyoyuk
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• v.3 no.1
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• pp.141-152
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• 1992

The purpose of this study is to search for the ways to diversify Outdoor/Environmental Education Program in the Nature Study Center(NSC), especially for the middle school students. For this study, various research methods such as literature review, questionnaire survey (448 students, 11 middle school teachers, 19 NSC staffs), interview and participant observation are used the process of this study consists of two steps. The first step is to define research questions through pilot survey and the second is to investigate the research questions, in the form of hypotheses through main survey. Nine hypotheses are formulated. Six are related with program elements (educational goals, student characteristics, staff resources, teaching methods, instructional resources, contents). three are related with program implementation process(preplan, implementation, post-evaluation). The hypotheses are tested and alternatives for program improvement are proposed. 1. Educational goals : Educational goals of NSC should be focused on Outdoor /Environmental Education and each NSC should specialize on its own theme. The objectives of every sub-program should be unified toward educational goals. 2. Student characteristics: The Outdoor/Environmental Education Program should reflect student characteristics: sex, urban/rural origins, normal/handicapped, number of visit and so on. 3. Staff resources : Provide qualified staff with professional knowledge and positive attitudes, reeducate staffs periodically, reduce management staff and increase teaching staffs. Provide permanent and well paid position, encourage and give opportunities and the middle school teachers to participate in program. 4. teaching method: Increase outdoor classes two way communication between teaching staffs and students adopt more open ended teaching method so that students can exercise coworks in small groups. 5. Instructional resources: Diversify NSC sites(mountains, coastal areas, urban areas and so on), teaching media (audio/visual equipments, graphic design of signs). Consider design for handicapped and integrate indoor and outdoor educational facilities. Plan nature trails with separate themes, allign nature trail so that it passes through diverse environments. 6. Content : Reflect characteristic site potential specialize on day or night program, on seasonal program, and on site specific social issues(such as interpreting of environmental damages around the NSCs). 7. Preplan: Get Information and know about visiting students in advance. Discuss with middle school teachers and adjust program weeks before visits if many or all of the students had already visited a NSC. arrange a visit to other NSC. Provide an introductory class for the teachers and students before they visit a NSC. 8. Implementation: During NSC visit and classes apply various and appropriate techniques to collect in formation for later evaluation. Improve NSC provided evaluation sheet so as to reflect student characteristic. Compare with formal education and investigate on effects of NSC program. 9. Post-evaluation: Formalize a post-evaluation process and organization. During the winter vacation, develop new programs based on the post-evaluationacation, for the next year. Also, have comparative evaluation meetings of staff from various NSCs during the winter vacation while there is no visitors and classes.

• Journal of Technology Innovation
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• v.18 no.2
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• pp.221-252
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• 2010

This study presents a concept of technology trade network and management, and proposes a procedural method for optimally selecting the technology transferor when a technology transferee needs to buy a specific technology. We develop a technology trade network where technology supplier, technology marketer, and technology transferee are informatively linked. And a technology trade management consists of three step of estimating technology, trading technology, and commercialization technology. Technology transferees could import the best appropriate technology which they want through these technology network method and cost optimization method. And we hope that these methodologies can be used in selecting new technology. A methodology can be classified into an estimating technology process and a choice of technology supplier process. In an estimating technology process, we calculate the technology similarity quantitatively through developing method of estimating technology which is focused on its technological characteristics. After defining the related cost of technology introduction, we suggest goal programming model to find a solution which can be acceptable both maximizing the technology similarity and minimizing the cost of technology. And suggested model is verified with a supplier selection problem of next generation tanks.