• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.42 no.11
• /
• pp.981-987
• /
• 2014

DC/DC switching power converters are commonly used to generate a regulated DC output voltage with high efficiency. The DC/DC converter is composed of a MOSFET (metal-oxide semiconductor field effect transistor), a PWM-IC (pulse width modulation-integrated circuit) controller, inductor, capacitor, etc. It is shown that the variation of threshold voltage and the breakdown voltage in the electrical characteristics of MOSFET occurs by radiation effects in TID (Total Ionizing Dose) testing at the low energy ${\gamma}$ rays using $^{60}Co$, and 5 heavy ions make the gate of MOSFET broken in SEGR (Single Event Gate Rupture) testing. TID testing on MOSFET is accomplished up to the total dose of 40 krad, and the cross section($cm^2$) versus LET(MeV/mg/$cm^2$) in the MOSFET operation is studied at SEGR testing after implementation of the controller board.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.54 no.8
• /
• pp.115-122
• /
• 2017

In this paper, we propose a novel power factor compensation system using slidac. The proposed power factor compensation system compensates the power factor by adjusting the output voltage of the slidac. In the conventional power factor compensation system using capacitor bank method, the power factor compensation error occurs depending on the load condition due to the limitation of the compensation capacitor capacity. However, the proposed system can finely change slidac output voltage applied to the capacitor, therefore power factor can be compensated up to 100% without error. We compare the proposed system with the conventional system, and confirm that the proposed system has excellent power factor compensation performance through simulations and experiments. If the proposed power factor compensation system is applied to an industrial field, a power factor compensation performance can be maximized. As a result, it is possible to reduce of electricity prices, reduce of line loss, increase of load capacity, ensure the transmission margin capacity, and reduce the amount of power generation.

• 한국정보교육학회:학술대회논문집
• /
• 2011.01a
• /
• pp.147-151
• /
• 2011

Educational efforts in integrating various subjects which are closely related to one another have had positive results. Additionally, integrating subjects has shown to be more effective than teaching subjects independently. The purpose of this study is to propose, construct, and develop a theme-based integrated program that teaches elementary school student's subjects which are outside the regular curriculum such as electricity, electronics, programming, and energy by using Diki-3000. Thus, having considered the theoretical background of theme-based integrated program, elementary school subjects including home economics, science, social studies, and extracurricular activities have been analyzed and restructured into theme-based program. Students will learn about and familiarize themselves with these subjects by utilizing the Diki-3000 product. This program aims to improve students understanding of the aforementioned subjects by combining Diki-3000's strengths as an educational tool with the contents of theme-based integrated program. Moreover, the learning experiences gained from completing critical problem-solving activities which are beyond normal subject knowledge is expected to help develop learners' positive thinking skills.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.12 no.1
• /
• pp.109-120
• /
• 2013

In this paper we proposed the design of the hybrid road lighting control system using solar-light generation. The proposed hybrid road lighting control system be power offer through hybrid controller using Solar-Light Generation, and it is designed so that it can control lighting up. To control supply of continuous power when during power shortages. And the gateway be transmit control command using zigbee to road lighting to ensure that automatic lighting control on human sensing. In this case, the gateway is apply the lighting control algorithm that decisions to the status of the system by a pre-set time schedule and be able to operate. In this paper, the proposed efficiency analysis results of a hybrid road lighting control system was consumed power of 129.6W per day, 3.8KW per month, 47.3KW per annual. As a result, it were able to increase the energy efficiency than existing lighting control system by reduce power consumption of 76.2% and the electricity prices of 76.8%.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.19 no.6
• /
• pp.191-196
• /
• 2019

In the case of urban railway facilities, the power supply should be maintained for the safe movement of passengers in communication facilities, disaster prevention facilities and boarding area security because of the confusion when power supply is cut off due to the nature of public transportation. In addition, considering that the number of trains is running on the urban railway line, it is necessary to operate at least 30 minutes for the bus stop and at least 1 hour for the communication and disaster prevention facilities. Therefore, it is essential to supply emergency power source to maintain stable operation of induction lamp and smoke exhaust system because main power is cut off in order to prevent further spread due to fire in case of the history of urban railway section or vehicle fires. Recently, UPS(Uninterruptible Power Supply) function to prevent power outage in emergency, emergency power generation combined with ESS function which saves electricity at nighttime price time, A hybrid power storage system with a UPS function.

• Journal of the Korean Data and Information Science Society
• /
• v.22 no.3
• /
• pp.401-412
• /
• 2011

This study uses a vector error correction model to analyze the daily time series data of the spot price of EUA (European Union Allowance). As endogenous variables, five variables are considered for the analysis, including prices of crude oil, natural gas, electricity and coal in addition to carbon price. Data period is Phase 2 period (April 21, 2008 to March 31, 2010) to avoid Phase 1 period (2005-2007) where the EUA prices were distorted. Unit-root and cointegration test results reveal that all variables have a unit root and cointegration vectors exist, so a vector error correction model is adopted instead of a vector autoregressive model.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.65 no.1
• /
• pp.31-40
• /
• 2016

The purpose of this study is to dimensionally examine the factors of policy changes by applying the ACMS model to KEPCO's structural reorganization privatization policies and study its implications. As a result of the analysis, among the external variables that affect as a financial source or restriction to advocates, all areas except for the difference in opinion of the people as well as policy decision and effects of other subordinate systems were shown to be in an advantageous condition acting as a financial source to advocates of structural reorganization privatization. On the other hand, advocates affected by the external variables share a certain belief system in which the advocates of privatization share the justification of profitability while the advocates of collectivization share the justification of publicness. In these flows, the announcement of the privatization plan of public enterprises of the committee of planning and budgeting acts as a matter of contact which opens the windows for policy changes, and this window goes through ignition, explosion, and fixation which causes fierce interactions among advocates of both sides. Eventually, in accordance with the contents of excluding electricity(KEPCO) from the list for privatization the window for policy changes has closed and things have changed to a transitional KEPCO privatization policy. Based on this, the first implication is that non-official participants such as the people, social organizations, labor unions, etc. influence policy changes more than they did before. Secondly, in the process of policy changes, there is an order of boundary even in the fierce interactions between each advocate. Thirdly, specific variables can play various roles in complex policy phenomenon. Fourthly, a logical analysis using the ACMS model is possible in Korea as well. Fifthly, as a result of analyzing the change process of the KEPCO structural reorganization privatization policy through the ACMS model, not all matched with the main research results implied by the ACMS model.

• Proceedings of the KIEE Conference
• /
• 2009.04a
• /
• pp.40-42
• /
• 2009

The economic growth and highly industrialized society have increased the demand for electricity power. As a result, concerns were focused on the energy resource scarcity and global warming. That is why the photovoltaic generation system to address these concerns has been in the spotlight recently. In this thesis, a utility interactive photovoltaic generation system was operated experimentally for the purpose of promoting the spread of the photovoltaic generation system in the future. Also, the effect of the type of array structure has on the performance of the photovoltaic generation system was evaluated quantitatively and by analyzing the comprehensive operating characteristics, the following results were obtained. In the demo system operated for a year, the average irradiation was measured to be 455,076 $[W/m^2]$ and the maximum irradiation to be 626,622 $[W/m^2]$ in May, up 171,546 $[W/m^2]$ or 38[%] compared with the average irradiation. The minimum irradiation was observed to be 294,022$[W/m^2]$ in December, down 161,054 $[W/m^2]$ or 35[%] compared with the average irradiation. The generation power in situation where there is plenty of irradiation was more than the average one, and the generation power in the fixed system amounted to 32[%], the single-axis tracker to 37[%], and the dual-axis tracker to 39[%]. The generation power in situation where there is little irradiation was less than the average one, and the generation power in the dual-axis tracker amounted to 41[%], the single-axis tracker to 40[%], and the fixed system to 36[%].

• Journal of the Economic Geographical Society of Korea
• /
• v.11 no.1
• /
• pp.148-163
• /
• 2008

As with cities, all components of a campus must be carefully calibrated to provide the facilities, services like energy, water, electricity, information and communication; classrooms, libraries and laboratories for working; transportation networks and systems for movement of persons, goods, and services; athletic and other facilities for health and competition; places to eat, recreate and socialize; places to display and store works of arts; spaces for the performing arts' spaces for active assembly or solitary pondering. The goal of this study is how to observe the campus planning and development as a part in the context of the community. This study was taken into account neighborhood concerns and Harvard design guidelines. As an observer for the university's northern campus edge, this study suggests in the context of a long and sometimes turbulent history of dialogue and negotiations between Harvard University and first host community, Agassiz which is one of Cambridge's thirteen neighborhoods.

• Journal of the Korea Society of Computer and Information
• /
• v.16 no.4
• /
• pp.101-110
• /
• 2011

A smart grid networks delivers electricity from suppliers to consumers using digital technology with two-way communications to control appliances at consumers' homes to save energy, reduce cost and increase reliability and transparency. Security is critically important for smart grid networks that are usually used for the electric power network and IT environments that are opened to attacks, such as, eavesdroping, replay attacks of abnormal messages, forgery of the messages to name a few. ZigBee has emerged as a strong contender for smart grid networks. ZigBee is used for low data rate and low power wireless network applications. To deploy smart grid networks, the collected information requires protection from an adversary over the network in many cases. The security mechanism should be provided for collecting the information over the network. However, the ZigBee protocol has some security weaknesses. In this paper, these weaknesses are discussed and a method to improve security aspect of the ZigBee protocol is presented along with a comparison of the message complexity of the proposed security protocol with that of the current ZigBee protocol.