• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.403-405
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• 1988

Recently, Power change devices using thyristor and transistor have grown with the rapid development of power electronics. But the devices using these semiconductors generate harmonics from the non-linear load, which gives rise to various obstacles. In this paper, therefore, as 3 taps are connected in input line, we can multiply the pulse in input line, by which harmonics is reduced.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.735-737
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• 2004

This paper proposes a method of fault diagnostics on switching mode power supply. When the error of switching mode power supply cannot be found when the conventional diagnostics is performed, this proposed method first performs diagnosis on the switching mode power supply strictly to judge the operating condition. This method analyzes the PWM wave which depends on the load change, to make sure the feedback control of the power supply to diagnosis the operation of the power supply system.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.743-745
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• 1999

In these days, pumped storaged power plants are under operations mainly for load regulation in power system. After we investigated the governor related electrical circuit of a pumped storaged power plant, we measured speed regulation and dead time of both the governor and the hydraulic system according to the change of variables of the governor during generation. After that the measured speed regulation improved much.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.153-156
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• 2001

The transformer and the OF cable are cooled and insulated by insulating oils in their body. The insulating oil expands or contracts with the heat transfer according to the operating conditions of the electric facilities. So we install the $N_2$ gas tank connected with the insulating oil system to overcome the change. The change of the insulating oil volume for the operation temperature range must be calculated to decide the $N_2$ gas volume and to set the alarm point for safe operation. It is known that this change is proportional to the temperature change and to the insulating oil volume if the temperature change is small enough.[1][11] However this proportional formula has been accepted generally in the design of electric facilities for wide operation temperature range such as $40^{\circ}C{\sim}125^{\circ}C$. Hence, it makes large errors in calculation which car result in serious damage against safe operation of the electric facilities. This paper presents a improved method of calculating the accurate change of the insulating oil volume to insure the safe operation of electric facilities.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.3 s.162
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• pp.387-397
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• 2007

Due to the recent trend of relationship marketing and characteristics of the apparel retail industry that relys heavily on employees' performance, internal marketing toward the employees gives a critical influence on firms' overall performance. This study is aiming at the factors of internal marketing and relationship management that enhance positive attitude toward change. A survey questionnaire was developed and about two hundreds department store sales staffs working for apparel brands participated in the empirical study. Factor analysis ensured the existence of five aspects of internal marketing: educational training, internal communication, power endorsement, management capability and incentive system. Results indicated that age, marital status, years of employment, position rank, and salary types of salespersons had significant influence on internal marketing factors. Incentive system had significant influence on internal customer relationship management. Internal customer relationship management had significant impact on employees' attitude toward change. Educational training had significant influence on employees' perceived importance of change. Educational training, power endorsement and incentive system affected employees' perceived outcome of change.

• Journal of the Korean Data and Information Science Society
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• v.14 no.2
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• pp.187-199
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• 2003

We deal with the problem of testing a sequence of independent normal random variables with constant, known or unknown, variance for no change in mean versus alternatives with a single change-point. Various tests based on the likelihood ratio and recursive residuals, score statistics and cusums are studied. Proposed tests are modified version of Buckley's cusum statistics. A comparison study of various change-point test statistics is done by Monte Carlo simulation with S-plus software.

• Analyses & Alternatives
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• v.1 no.2
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• pp.44-64
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• 2017

From the field survey of the main ethnic minority areas in the south China, it is found that political, economic, cultural and natural environmental changes are the main reasons leading to the change of customary law. The power mechanism of the customary law change include the three aspects, such as the promotion of country elite, the dominance of grassroots government, and the daily demands of the villagers, which promote the change of customary law alone or together. Through the application of customary law, the country elites can adjust and refine the rules of customary law in order to make out the new customary law and promote its development. In the current pattern of rural governance, grassroots self-government is actually the "official supervision of people's autonomy". The executive power of the grassroots government often intervene the practice of customary law and other informal rules. This is another mechanism of customary law change. Customary law arises from the practice of the daily life of the villagers. If the villagers think that the norms of customary law cannot meet the actual needs of daily life practice, the customary law will be promoted in the form of collective consultation. This is the most important dynamic practice mechanism of customary law change. Transformation and abandonment are the two ways to change customary law. No matter what kind of change does not lead to the demise of the customary law system, the demise of the customary law is only an outdated result, which is made by the universality, nature and objectivity of customary law. The procedure of customary law change is the process of continuation and rebirth about customary law. The result of the change is to produce the new customary law of keeping pace with the times, and the customary law will be presented with new content and form after the change. The continuation of customary law means the inheritance of traditional customary law, but it is based on the transformation of traditional customary law. The rebirth of customary law means that the traditional customary law is completely discarded. But it will produce new customary law rules and be based on the needs of social life practice. Customary law occupies a pivotal position in the normative system and the national law cannot be replaced. The purpose of customary law change will let the customary rules better adapt to the development of modern society, adjust the social relations more reasonably and better meet people's needs of production and life, which is decided by the character of customary law.

• Transactions on Electrical and Electronic Materials
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• v.15 no.6
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• pp.328-332
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• 2014

Thin film transistors (TFTs) with an amorphous silicon zinc tin oxide (a-2SZTO) channel layer have been fabricated using an RF magnetron sputtering system. The effect of the change of excitation electron on the variation of the total interfacial trap states of a-2SZTO systems was investigated depending on sputtering power, since the interfacial state could be changed by changing sputtering power. It is well known that Si can effectively reduce the generation of the oxygen vacancies. However, The a-2SZTO systems of ZTO doped with 2 wt% Si could be degraded because the Si peripheral electron belonging to a p-orbital affects the amorphous zinc tin oxide (a-ZTO) TFTs of the s-orbital overlap structure. We fabricated amorphous 2 wt% Si-doped ZnSnO (a-2SZTO) TFTs using an RF magnetron sputtering system. The a-2SZTO TFTs show an improvement of the electrical property with increasing power. The a-2SZTO TFTs fabricated at a power of 30 W showed many of the total interfacial trap states. The a-2SZTO TFTs at a power of 30 W showed poor electrical property. However, at 50 W power, the total interfacial trap states showed improvement. In addition, the improved total interfacial states affected the thermal stress of a-2SZTO TFTs. Therefore, a-2SZTO TFTs fabricated at 50 W power showed a relatively small shift of threshold voltage. Similarly, the activation energy of a-2SZTO TFTs fabricated at 50 W power exhibits a relatively large falling rate (0.0475 eV/V) with a relatively high activation energy, which means that the a-2SZTO TFTs fabricated at 50 W power has a relatively lower trap density than other power cases. As a result, the electrical characteristics of a-2SZTO TFTs fabricated at a sputtering power of 50 W are enhanced. The TFTs fabricated by rf sputter should be carefully optimized to provide better stability for a-2SZTO in terms of the sputtering power, which is closely related to the interfacial trap states.

• Journal of Climate Change Research
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• v.9 no.2
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• pp.197-207
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• 2018

The Korean government views coal-fired power plants as the key cause of the fine dust generation, and is developing an energy policy to replace and demolish old coal-fired power plants. According to the Eighth Power Supply Base Plan (2017-2031), the maximum power capacity in 2030 is expected to be 100.5GW, which is 17.9% higher than the current level (85.2GW). The plan aims to reduce the facility size and power generation ratio from nuclear and coal resources to even lower levels than today, and to rapidly expand power generation from new and renewable energy. Despite that, the proportion of coal power generation is still much higher than other resources, and it is expected that the reliance on goal will maintain for next several decades. Under such circumstances, the development, supply, and expansion of clean coal technology (CCT) that is eco-friendly and highly efficient, is crucial to minimize the emission of pollutants such as carbon dioxide and fine dust, as well as maximize the energy efficiency. The Korean government designated the Yong-Dong Thermoelectric Power Plant in Gangneung to develop clean coal power generation, and executed related projects for three years. The current study aims to suggest a plan to develop parts, technologies, testing, evaluation, certification, and commercialization efforts for coal-fired power generation, In addition, the study proposes a strategy to vitalize local economy and connect the development with creation of more jobs.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1584-1602
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• 2024

It is vital to output the required electrical power following various task requirements when the space reactor power supply is operating in orbit. The dynamic performance of the closed Brayton cycle thermoelectric conversion system is initially studied and analyzed. Based on this, a load tracking power regulation method is developed for the liquid metal cooled space reactor power system, which takes into account the inlet temperature of the lithium on the hot side of the intermediate heat exchanger, the filling quantity of helium and xenon, and the input amount of the heat pipe radiator module. After comparing several methods, a power regulation method with fast response speed and strong system stability is obtained. Under various changes in power output, the dynamic response characteristics of the ultra-small liquid metal lithium-cooled space reactor concept scheme are analyzed. The transient operation process of 70 % load power shows that core power variation is within 30 % and core coolant temperature can operate at the set safety temperature. The second loop's helium-xenon working fluid has a 65K temperature change range and a 25 % filling quantity. The lithium at the radiator loop outlet changes by less than ±7 K, and the system's main key parameters change as expected, indicating safety. The core system uses less power during 30 % load power transient operation. According to the response characteristics of various system parameters, under low power operation conditions, the lithium working fluid temperature of the radiator circuit and the high-temperature heat pipe operation temperature are limiting conditions for low-power operation, and multiple system parameters must be coordinated to ensure that the radiator system does not condense the lithium working fluid and the heat pipe.