• Journal of Power Electronics
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• v.12 no.6
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• pp.912-924
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• 2012

In hybrid renewable power systems, the use of a multiple-input dc/dc converter (MIC) leads to simpler circuit and lower cost, when compared to the conventional use of several single-input converters. This paper proposed a novel three-input buck/boost/buck-boost converter, which can be used in applications with various values of input voltage. The energy sources in this converter can deliver power to the load either simultaneously or individually in one switching period. The steady relationship, the power management strategy and the small-signal circuit model of this converter have been derived. With decoupling technology, modeling and regulator design can be obtained under multi-loop control modes. Finally, three generating methods of a multiple-input buck/boost/buck-boost converter is given, and this method can be extended to the other multiple-input dc/dc converters.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.4_1
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• pp.411-419
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• 2021

In this study, IGBT_Total_Loss and DIODE_Total_Loss were used to analyze the slope of the junction temperature for each section for temperature and duty variables in order to simply calculate the junction temperature of the power semiconductor (IGBT). As a result of the calculation, IGBT_Max_Junction_Temp and DIODE_Max_Junction_Temp form a proportional relationship with temperature for each duty. This simulation data shows that the power loss of a power semiconductor is calculated in a complex manner according to the current dependence index, voltage dependence index, and temperature coefficient. By applying the slope for each condition and section, the junction temperature of the power semiconductor can be calculated simply.

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1327-1337
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• 2019

The purpose of this study is to study the relationship between quality of education service in scuba diving and customer satisfaction and willingness to buy again. Scuba of scuba diving in Seoul was selected as a population and a total of 200 questionnaires were distributed using the "conven-ence sampling" among the non-probability sampling methods. A total of 154 data were used as valid samples, except for 46 questionnaires that were found to have been unfaithfully answered. The data processing method was used by the SPSS18.0 program to perform frequency analysis, exploratory factor analysis, correlation, and multiple regression analysis. The results of this study are as follows. First, after analyzing the relationship between the quality of education service and customer satisfaction, the facilities among the quality of education services (β=).349), Program (β=.340) has been shown to affect satisfaction. In addition, if we look at customer satisfaction of the quality of education services, we find that the quality of education has an explanatory power of about 47% of the total quantity of the quality of education services. Second, after analyzing the relationship between the quality of education services and the repurchase, the cost of the quality of education services (β =).215), a program (β=.442) was found to affect repurchase. Also, if we look at the ability to explain the repeat purchase of the quality of education services, it is found that it has an explanatory power of about 53% of the total quantity of the quality of education services. Third, after analyzing the relationship between customer satisfaction and repurchase (β=).555) was found to affect repurchase. In addition, if we look at the explanatory power of resurchasing satisfaction, we find that it has an explanatory power of about 55% of the total quantity.

• Journal of Families and Better Life
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• v.5 no.2
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• pp.127-144
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• 1987

The purpose of this study is to explore the family communication and power. Communication is a symbolic, transactional process in functional view . To say tat communication is a process implies a continuous interaction of an indefinite large number of variables with a concomitant, continuous change in the values taken by these variables. Finally the process implies change. Family functions include the primary functions of cohesion and adaptability and supporting functions of family images, themes, boundaries, and biosocial issues, The primary functions reveal concepts integrated family interaction and supporting functions, along with those of cohesion and adaptability, give shape of family life. The message system is the major element of communication process and influences both the form and the content of thier relationship and create and share meanings. The family-of-origin issues influence all aspects of family communication and account for many of the communication patterns, rules and networks. Power does not belong to an individual. rather it is a property of a relationship between two or more persons, Power, a system property is the ability of an individual to change the behavior of other members in a social system. Power operate transactionally in a family and any power maneuvers within it have a system wide effect. In order to study power in families , it is necessary to examine 1) family power operations 2) development of family power and 3) the communication of power strutegies. The research presented indicated that a rigid power structure, characterized by dominance and little sharing, restricts family flexibility reduce cohesion, and adversely affects satisfaction in families. power constantly changes as a family grows and develops within its system. Although power changes may be more obvious in children as they mature and more from a independent stated to an independent one, each of the parents experience egual or greater. Communication and activities take place that either enhance positively or negatively the images, themes, and degree of unity of cohesion the family desires. Power operated within a dynamic, growing, changing, interdependent transactional family system. Power struggle may develop when as issue becomes important to one or more family member. When this happens, and the rational exploration of alternatives ceases, various one-up power maneuvers usally follows, This affect family intimacy. a vital element in meaningful relationships . To resolve differences and not become the victim of another's power , one need to engage in constructive conflict since the ability to clearly and comfortably repudiate another is part of the achievement of intimacy.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1422-1431
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• 2015

The reliability of power system components can be affected by a numbers of factors such as the health level of components, external environment and operation environment of power systems. These factors also affect the electrical parameters of power system components for example the thermal capacity of a transmission element. The relationship of component reliability and power system is, therefore, a complex nonlinear function related to the above-mentioned factors. Traditional approaches for reliability assessment of power systems do not take the influence of these factors into account. The assessment results could not, therefore, reflect the short-term trend of the system reliability performance considering the influence of the key factors and provide the system dispatchers with enough information to make decent operational decisions. This paper discusses some of these important operational issues from the perspective of power system reliability. The discussions include operational reliability of power systems, reliability influence models for main performance parameters of components, time-varying reliability models of components, and a reliability assessment algorithm for power system operations considering the time-varying characteristic of various parameters. The significance of these discussions and applications of the proposed techniques are illustrated by case study results using the IEEE-RTS.

• Knowledge Management Research
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• v.7 no.1
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• pp.49-63
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• 2006

The objective of the study is to verify the discriminatory power of technology innovation in predicting Early Stage Ventures' success or failure. To accomplish this objective, we test early stage ventures'(Firm's period is below 3 years)technology innovation and performance. The result of the study is expected to be useful in loan evaluation, investment decision, internal management decision making and business improvement. The results of study is as follows. First, Early Stage Ventures' technology innovation power is composed of 4 major indexes(technology, marketability, manufacturing infra and economic feasibility). Second, we find that thirty-seven minor indexes are significant ex-ante variable which are discriminating between firms' success and failure in Early Stage Ventures. Also thirty-seven minor indexes explain 57.2% of the total variance. This explainable power of these indexes is similar to that of the existing 58 index elements. Finally, we find that the most important technology innovation power of Early Stage Ventures' is economic feasibility.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.8
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• pp.498-500
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• 2005

In a CDMA system, the capacity is variable and mainly depends on multiple access interference. The multiple access interference has a deep relationship with transmitted or received power The capacity of CDMA2000 1x system is considered to be limited by the forward link capacity Different rate data traffic requires different transmitted power and rate controlling enables the system utilize radio resource more efficiently. A very simple rate control algorithm for data calls in CDMA2000 1x system is proposed. In the proposed algorithm, by monitoring the total transmit power, we can simply adjust data rate to channel conditions and efficiently use radio resources. The proposed algorithm is easy to implement in power controlled CDMA systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.2
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• pp.245-249
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• 2014

Wireless power transfer (WPT) system is very attractive because it removes power cables from home appliances, office equipments and battery chargers for electric vehicles. In this paper, non-radiative WPT systems studied recently are claimed to be technologically or theoretically identical in operation irrespective of the number of coils. Especially, 2-coil and 3-coil systems are compared in detail. It is also shown that multiplicity of coils does not increase power transfer capability.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.221-223
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• 2005

In a CDMA system, the capacity is variable and mainly depends on multiple access interference. The multiple access interference has a deep relationship with transmitted or received power. The capacity of CDMA2000 1x system is considered to be limited by the forward link capacity. Different rate data traffic requires different transmitted power and rate controlling enables the system utilize radio resource more efficiently. A very simple rate control algorithm fer data calls in CDMA2000 1x system is proposed. In the proposed algorithm, by monitoring the total transmit power, we can simply adjust data rate to channel conditions and efficiently use radio resources. The proposed algorithm is easy to implement in power controlled CDMA systems.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.1
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• pp.5-12
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• 2002

The grinding process has been mainly used fur finishing metal products as final machining stage. But chatter vibration and bum of a workpiece have a bad effect on the machined surface and should be detected in modern grinding process. This paper deals with a fault detection of the cylindrical plunge grinding process by power parameters. During the grinding process the power signals of an induced motor were sampled and used to determine the relationship between fault and change of power parameters. A neural network was used far detecting the grinding fault and an influence of power parameters to the grinding fault was analyzed.