• Journal of Electrical Engineering and Technology
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• v.4 no.3
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• pp.346-352
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• 2009

The eventual goal of this paper is to help the generating companies and load-serving entities to choose appropriate relative levels of interconnected system versus bilateral trades while considering risk, and economic performance. In competitive power markets, electricity prices are determined by balance between demand and supply in electric power exchanges or bilateral contracts. The problem formulation is bilateral contract incorporated into Multi-area unit commitment with import/export and tie-line constraints. This proposed method considers maximizing own profit or minimize the operating cost among the generating companies in multi-area system. The feasibility of the proposed algorithm has been demonstrated using IEEE system with four areas and experimental results shows that proposed method is reliable, fast and computationally efficient

• 대한공업교육학회지
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• v.36 no.1
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• pp.1-22
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• 2011

The purpose of this study was to develop and apply activity-centered STEM education program of electricity and electronics technology are in middle schools. The program was developed on the emphasis of problem solving in real world in relation to knowledge, attitude, and skill of Science, Technology, Engineering, and Mathematics. Basically the activity-centered STEM education program was developed through three steps of preparation, development and improvement. In the preparation stage the fellowing was included: (1) need analysis of student, educator, society (2) selection of integration type (3) analyzing subject matter of electricity, electronics area (4) establishing criteria for selecting activity tasks. In the development stage the fellowing was conducted: (1) selection of activity tasks (2) setting up educational goals (3) analyzing activity and clarifing the detailed activity (4) selecting program content, (5) organization of instructional content (6) statement of instructional objectives (7) structuring STEM education program In the improvement stage the fellowing was consisted of: (1) verification of validity by experts (2) execution of pilot test and field test by students and correction of program. The results of the applied the Activity-Based STEM Education Program to 'Afterschool' activities of S middle school were as follow: First, student' satisfaction level was high. Second, student' achievement in the cognitive domain, and affective domain was positive change. Third, student' problem solving ability was positive effect.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.172-176
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• 2004

In this paper, We are inclined to design automated mushroom-cultivation system technology grafting communication technology as CAN(Control Area Network). Mushroom cultivation automated system have a goal to construct stable crop cultivation system ,as we construct embedded-system that can make into one to advance current system. Its sensor part is composed of temperature , humidity and CO2 concentration sensor and of chilling, heating and unit humidity-controlling unit, ventilation fan. In particular, having saved analized temperature, humidity, CO2 concentration data in each sensor, CAN which can control realtime communication is used to analyze the next mushroom-cultivation.

• Journal of Power Electronics
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• v.12 no.1
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• pp.208-214
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• 2012

This paper presents a novel approach based on the loci of instantaneous symmetrical components called "Wing Shape" which requires the measurement of three input stator currents and voltages to diagnose interturn insulation faults in three phase induction motors operating under different loading conditions. In this methodology, the effect of unbalanced supply conditions, constructional imbalances and measurement errors are also investigated. The sizes of the wings determine the loading on the motor and the travel of the wings while their areas determine the degree of severity of the faults. This approach is also applied to detect open circuit faults or single phasing conditions in induction motors. In order to validate this method, experimental results are presented for a 5 hp squirrel cage induction motor. The proposed technique helps improve the reliability, efficiency, and safety of the motor system and industrial plant. It also allows maintenance to be performed in a more efficient manner, since the course of action can be determined based on the type and severity of the fault.

• Current Photovoltaic Research
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• v.11 no.2
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• pp.49-53
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• 2023

Expanding the supply of BIPV is crucial to strengthening the competitiveness of the photovoltaic industry and achieving Nationally Determined Contributions through the zero-energy building mandatory policy. BIPV is a technology that integrates into the building envelope to generate electricity and provide functions as a building material. It is suitable for domestic environments with many high-rise buildings due to the narrow land area and urbanization. To expand the supply of BIPV, economics, safety, and aesthetics must be ensured. In this study, a color BIPV module with a color PET film applied as a front material was manufactured for aesthetic and economic feasibility. The relationship between power output and transmittance according to color was analyzed. By analyzing the power output of the module and the transmittance of the film, the wavelength band (transmittance reduction band) that has the greatest effect on efficiency was analyzed regarding the color of the film. The red film showed the narrowest transmittance reduction band and the lowest degree of decrease in transmittance, making it ideal for minimizing the efficiency decrease rate compared to existing ones.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.1
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• pp.36-39
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• 2014

MFC(microbial fuel cell) is the device to produce the electricity by using the microbes which are living in the waste water. In this paper, the electric characteristics of the MFC were investigated according to each different structure and electrode materials. The voltage being reversed phenomenon was observed in the MFC which uses the cupper plate as the cathode material. This result comes from the oxidation reaction of the cupper plate electrode in this MFC. And this MFC has lower output voltage than one that has a platinum plate electrode. The smaller gap distance of the cupper plate electrode of the MFC showed the higher output voltage. The larger electrode area of the cupper plate electrode showed that the reaching time of the output voltage to the maximum value was delayed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.3
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• pp.9-16
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• 2008

We centrally study effect of very high voltage 345kV T/L which is set up at residential area (Yangyang~Donghae in Gangwon-do) to broadcasting radio wave and human body. First, to compare predicted result of radio wave disturbance, we set 7 area 13 point and divide broadcasting quality, electric and magnetic fields in T/L process. Result of estimation, we confirm that when receiving broadcasting radio wave, broadcasting quality's difference is generated by topographic property of near receiving point. also through result of electric fields and broadcasting quality and their comparison, we judge that high voltage T/L is barely affect receive of broadcasting radio wave. To judge effect of magnetic fields to human body, we analyze magnetic fields in variable area and condition. as a result, magnetic fields of every area has 1.8mG(WHO international standard amount is 833mG). So It is proved that magnetic fields of 345kV Yangyang~Donghae area has slight, tiny effect to human body.

• Journal of Practical Engineering Education
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• v.10 no.1
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• pp.73-79
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• 2018

The purpose of this study is to explore the supporting scenario to promote vocational training in North Korea in terms of cooperation level. To this end, we have embarked on a regional and industry based vocational training program by predicting the political and social situation of North Korea and staging three scenarios systematically. These scenarios were designed originally based on the Futures Group methodology. The first scenario is to establish a technical training center in one area, focusing on the electrical, electronics, and clothing sectors. The second scenario is to set up a pilot campus of vocational training college in one region by selecting the electric, electronic, and automobile industries as its main industries. The third scenario is to establish five vocational training college campuses in North Korea, focusing on electricity and electronics, IT manufacturing, telecommunications, heavy industry, and women-specialized industries. We suggested the followings: First, establishing goals and strategies for North Korean vocational training and establishing road maps. Second, the North Korean vocational training governance system needs to be established. Third, R & D infrastructure for vocational training needs to be established. Fourth, HRD and HRM system in North Korea vocational training field needs to be established. In addition, the role of public and private employment services centers to provide them should be strengthening.

• Journal of Korean Home Economics Education Association
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• v.17 no.4 s.38
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• pp.133-156
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• 2005

This study clarifies the concept of the education content relevance in order to evaluate the content relevance of Technology & Home Economics in a secondary school, and design its standards based on the preceding study. In other words, four standards such as the amount of studying content, the degree of difficulty, the validity of contents and the sequence of contents are established. Also, a survey on the current status of nationwide units targeting students, teachers, and professors was conducted to collect actual data about relevance evaluation. The results are as follows. First, as for the evaluation in terms of the amount of studying content, the majority of respondents answered that it decreased by about $30\%$ when compared to the 6th Technology & Home Economics Curriculum However, middle school teachers pointed out that the number of classes is not enough considering the fact that it's an activity-oriented subject. So, they acknowledged that the amount of study time during a Technology Sl Home Economics class is 'quite a lot.' Second, the evaluation in the degree of difficulty is divided into two responses. Teachers responded that it's reasonable overall, but according to students, it's difficult. Especially, the chapters that students don't understand well including 'The Elements of Draftsmanship,"' 'Understanding of Machinery,' 'Electronics & Electricity Technology,' and 'Energy & Transportation Technology.' In the Home Economics area, 'The Design of Home Life' is the only chapter that students don't understand well. Third, as for the validity of contents, the chapters that were not considered as important considering the objective of Technology Sl Home Economics Curriculum include 'The Elements of Draftsmanship,' 'Computer & Processing,' and 'The Management of Resources and Environment.' Fourth, as for the sequence of contents, the survey was conducted including the name of the course asone of the survey items. The majority of teachers wanted it as it is, but the Professors of education colleges who wanted the 3rd name to connect the course with the elementary school course was a little more $(50.5\%)$ than the ones who don't want any changes $(45.5\%)$. The follow-up study should correct and complement the standards that this study suggested through analytic and critical review according to the character & goal of the subject. Based on such standards, the evaluation of content relevance should be continued to realize the quality control of the curriculum systematically.

• Journal of the Korean Electrochemical Society
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• v.19 no.3
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• pp.69-79
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• 2016

Lithium ion battery with high energy density is expanding its application area to electric automobile and electricity storage field beyond existing portable electric devices. Such expansion of an application field is demanding higher characteristic and stable long life characteristic of an anode material, the natural graphite that became commercialized in lithium ion battery. This thesis produced cathode by using natural graphite anode material, analyzed creation of the cathode SEI film created due to initial reaction by using electrolyte additives, VC (vinylene carbonate), VEC (vinyl ethylene carbonate), and FEC (fluoroethylene carbonate), and considered correlation with the accompanying electrochemical transformation. This study compared and analyzed the SEI film variation of natural graphite cathode according to the electrolyte additive with SEI that is formed at the time of initial filling and cathode of $60^{\circ}C$ life characteristic. At the time of initial filling, the profile showed changes due to the SEI formation, and SEI was formed in No-Additive in approximately 0.9 V through EVS, but for VC, VEC, and FEC, the formation reaction was created above 1 V. In $60^{\circ}C$ lifespan characteristic evaluation, the initial efficiency was highest in No-Additive and showed high contents percentage, but when cycle was progressed, the capacity maintenance rate decreased more than VC and FEC as the capacity and efficiency at the time of filling decreased, and VEC showed lowest performance in efficiency and capacity maintenance rate. Changes of SEI could not be verified through SEM, but it was identified that as the cycle of SEI ingredients was progressed through FT-IR, ingredients of Alkyl carbonate ($RCO_2Li$) affiliation of the $2850-2900cm^{-1}$ was maintained more solidly and the resistance increased as cycle was progressed through EIS, and specially, it was identified that the resistance due to No-Additive and SEI of VEC became very significant. Continuous loss of additives was verified through GC-MS, and the loss of additives from partial decomposition and remodeling of SEI formed the non-uniform surface of SEI and is judged to be the increase of resistance.