• Title/Summary/Keyword: Self-switching

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Numerical Analysis of Switching Arcs with the Ablation of PTFE Nozzles (PTFE 노즐로부터 발생하는 용삭가스를 고려한 스위칭 아크 해석)

  • Lee, Won-Ho;Kim, Hong-Kyu;Lee, Jong-Chul
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1536-1537
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    • 2011
  • The high-voltage circuit breaker plays an important role in the electrical system because there has been a need for suitable switching devices capable of initiating and interrupting the flow of the electric fault current. It continues as the contacts recede from each other and as the newly created gap is bridged by a plasma. The arc plasma happens inside the insulation nozzle of SF6 self-blast interrupter which is newly developed as the next-generation switching principle. The ablation of PTFE nozzle is caused by this high temperature medium, the PTFE vapor from the nozzle surfaces flows toward the outlets and the pressure chamber. The vapor makes the pressure of the chamber increased by heat and mass transfer from the arcing zone. Because the rate of ablation depends on the magnitude of applied current, it decreases when the current goes to zero. The compressed gas inside the chamber flows reversely toward the arc plasma during this moment. According to this principle, the arc can be cooled down and the fault current can be interrupted successfully. In this study, we calculate arc plasmas and thermal-flow characteristics caused by fault current interruption inside a SF6 self-blast interrupter, and to investigate the effect of PTFE ablation on the whole arcing history.

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Self-similarity of SMS Traffic (SMS 트래픽의 Self-similarity)

  • Ha, Jun;Shin, Woo-Cheol;Park, Jin-Kyung;Choi, Cheon-Won
    • Proceedings of the IEEK Conference
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    • 2003.11c
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    • pp.353-356
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    • 2003
  • As the wireless mobile telecommunication system has been developed with astonishment, its offering service has also widely been expanded including various data service. Currently, the wireless mobile telecommunication network presents voice service that covers for the most part of the whole service areas. For this reason, the availability of the switching capacity in the mobile switching center(MSC) is manipulated by the required volume of voice service. However, considering the increase of data service, it is desirable for the current switching method to be modified for more efficiency. In this Paper, we analyze the data traffic caused by providing data service in the wireless mobile telecommunication network. For this, we are firstly going to review the result of the analysis in the feature of the data traffic. Secondly, based on the review, we are also going to perform analyzing the other feature of the data traffic normally generated in the wireless mobile telecommunication network. We expect that this paper would be utilized as an elementary source for the feature of the SMS data .traffic and it will be an honour for ourselves to work on it.

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Clamp mode forward multi-resonant conveter with synchronous rectifier (동기 정류기를 이용한 클램프 모드 포워드 다중 공진형 컨버터)

  • 안강순;김희준
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.2
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    • pp.112-120
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    • 1997
  • The clamp mode (CM) forward zero voltage switching multi resonant converter (ZVS-MPC) with self-driven synchronous rectifier is studied. The loss at the synchronous rectification stage of the converter is analyzed using MOSFET piecewise linear model and is compared with the loss at the conventional schottky diode rectification stage of th econverter. From the results of the analysis, it is known that the use fo MOSFETs as a synchronous rectifier reduces the loss at the rectification stage overthe whole load range comparing the use of schottky diodes as a conventional rectifier in the converter. In order to verify the validit of the analysis, we have built a 33W(3.3V/10A) CM forward ZVS-MRC with self-driven synchronous rectifier, in which switching frequency is 1MHz, and tested. FRom the experimental results, it is known that the synchronous rectification achieved about 1W improvement in the loss at the rectification stage and about 3% in the efficiency at the converter as compared with the conventional schottky diode rectification.

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Influence of Shopping Orientation of Female Consumers in Their 20s and 30s on Motivation for Brand-Switching in Purchasing Cosmeceuticals -Focusing on Whitening, Sunscreen, and Anti-Aging Treatments- (기능성 화장품 쇼핑성향이 상표전환 동기에 미치는 영향)

  • Kim, Myung Hee;Hwang, Choon Sup
    • Journal of the Korean Society of Clothing and Textiles
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    • v.37 no.3
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    • pp.334-347
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    • 2013
  • This study obtains information required for a comprehensive understanding of the brand-switching behavior by cosmetics consumers and for the establishment of effective strategies to make customers more loyal to the company. The study examines the relationships between customer shopping orientation and brand switching motives with respect to cosmeceuticals. A descriptive survey method using a self-administered questionnaire was employed. The sample consisted of 1,258 females between the ages of 20's and 30's residing in Seoul and the Gyeonggi area who use whitening products, sunscreen, or other anti-aging cosmetics. The results showed that shopping orientation influenced brand-switching motives in regards to purchasing cosmeceuticals. The orientation of depending on information and seeking fashion trend were the major factors to induce brand-switching behavior in purchasing whitening products, sunscreen, and anti-aging treatments. However, there were differences in the type of factors of shopping orientation and in their intensity of affecting brand-switching motives depending on the specific cosmeceuticals. In particular, in the case of sunscreen, as compared to other products, the customer shopping orientation should be considered from more diverse perspectives in order to formulate effective marketing strategies related to brand switching. In light of these results, customer shopping orientation with respect to cosmeceuticals is a variable that influences the cause brand switching. Therefore, differentiated marketing strategies that reflect the different characteristics of shopping orientation according to each item of cosmeceuticals are recommended to improve the satisfaction level of the companies' target market. Current consumer needs for practical benefits and for new products should be simultaneously reflected in the plans for new product development of each type of cosmeceutical.

The Impact of Patient Satisfaction With Nursing Care Services, Switching Costs and Perceived Risk on Intention of Reuse in the Emergency Medical Center (응급의료센터 내원환자의 간호서비스 만족도, 전환비용 및 지각된 위험이 재이용 의도에 미치는 영향)

  • Kim, Hyun-Jeong;Yom, Young-Hee
    • Journal of Korean Academy of Nursing Administration
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    • v.17 no.4
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    • pp.432-442
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    • 2011
  • Purpose: The purpose of this study was to identify the factors influencing the intention of the reuse in patients admitted in university hospital emergency medical center. Method: The participants were 253 patients admitted to a niversity hospital emergency medical center. Data were collected with self-administrated questionnaires and analyzed by hierarchical multiple regression. Results: Patient satisfaction with nursing care service and switching cost were positively correlated with reuse by patients while the perceived risk was negatively correlated. As levels of satisfaction with nursing care services and switching cost increase, intention of reuse increases. Satisfaction with nursing care service, switching cost and perceived risk in emergency medical center influence intention to reuse and explain 68.8% of total variation of intention to reuse. Conclusion: Findings provide strong empirical evidence for importance of atient satisfaction with nursing care service, the switching costs and the perceived risk in explaining the intention of reuse an emergency medical center.

The Impact of Life Satisfaction, Quality Consciousness, and Religiosity on Customer Switching Intention to Halal Cosmetic

  • USMAN, Hardius;PROJO, Nucke Widowati Kusumo;WULANSARI, Ika Yuni;FADILLA, Thasya
    • Asian Journal of Business Environment
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    • v.11 no.3
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    • pp.5-19
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    • 2021
  • Purpose: The purpose of this research is to study the role of life satisfaction, quality consciousness, and religiosity, which are integrated with the TRA Model to explain the switching intention of Muslim consumers to use Halal Cosmetics and Personal Care (HCPC). The second purpose is to investigate the relationship between variables used in this study to provide recommendations to HCPC producers about Muslim consumer behavior in the market. Research design, data, and methodology: The target population in this study is Muslims who live in Greater Jakarta. Data collection is carried out by the self-administered survey method based on the Purposive sampling technique, and the questionnaire is distributed online. The statistical analysis to test the research hypotheses is the Partial Least Squares - Structural Equation Model (PLS-SEM). Results: Life satisfaction, product quality consciousness, and religious commitment have a significant effect on attitude to switching but do not significantly influence the intention of switching to use HCPC. Conclusions: Life satisfaction, quality consciousness, and religiosity that represent individual factors indirectly affect the intention to switch to use HCPC. Thus, religious commitment influences attitude to switching both directly and indirectly.

Linking Benefit/Cost, Negative Attitudes toward Shadow Work, and Consumer's Response Behavior (혜택/비용, 그림자 노동에 대한 부정적 태도, 반응행동 간 구조적 관계)

  • Liu, Ting Ting;Koh, Joon
    • The Journal of Information Systems
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    • v.30 no.2
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    • pp.79-103
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    • 2021
  • Purpose Based on consumers' economic, psychological, self-development and conversion costs, this study discusses the relationship between consumers' negative attitude to their shadow work during the course of using self-service in unmanned supermarkets and their behavior. Design/methodology/approach Along with the Hirschman(1970)'s EVLN(Exit, Voice, Loyalty, and Neglect) reviewed, the proposed model of this study is based on the S-O-R model(Mehrabian and Russel, 1974) and mental accounting theory(Thaler, 1999), having empirical validation. Findings In the process of visits and consumption in unmanned supermarkets, increasing economic and psychological benefits can effectively reduce consumers' negative attitudes towards shadow work. In addition, the increase in switching costs will also effectively reduce consumers' negative attitudes towards shadow work. When shadow work holds a negative attitude, all the three kinds of actions will occur. Unmanned supermarket operators use consumers to create value while giving a certain return to them, which is conducive to the sustainable development of unmanned supermarket enterprises.

A study on the switching character and loss of power semiconductor device (전력용 반도체 디바이스의 스위칭 특성과 손실에 관한 연구)

  • Kim, Yong-Ju;Han, Suk-Woo;Ma, Young-Ho;Kim, Han-Sung;Yu, Gwon-Jong
    • Proceedings of the KIEE Conference
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    • 1990.11a
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    • pp.263-266
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    • 1990
  • In order to high-respone and high-reliability of devices, it depended upon how we can increase the high-frequency of the Inverter, UPS and it's application. but using high-frequency of self turn-off devices, it is important to reduce switching device loss and spike voltage of turn off. This paper proposed new methode about computer simulation of device loss also experimental results with switching device characteristic are presented.

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Hysteresis Current Control with Self-Locked Frequency Limiter for VSI Control (자기동조 주파수 제한기를 갖는 전압원 인버터의 히스테리시스 전류제어)

  • Choe, Yeon-Ho;Im, Seong-Un;Gwon, U-Hyeon
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.1
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    • pp.23-33
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    • 2002
  • A hysteresis control is widely used to control output current of inverter. A hysteresis bandwidth is affected by system parameters such as source voltage, device on/off time, load inductance and resistance. The frequency limiter is used to protect switching devices overload. In the conventional hysteresis controller, a lock-out circuit with D-latch and timer is used to device protection circuit. But switching delay time and harmonic components are appeared in output current. In this paper the performance of lock-out circuit is tested, and new circuit for switching device fault protection is proposed ad it's performance is simulated.

A New Soft Switching Step-Down/Up Converter with Inherent PFC Performance

  • Jabbari, Masoud;Farzanehfard, Hosein
    • Journal of Power Electronics
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    • v.9 no.6
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    • pp.835-844
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    • 2009
  • In this paper a new buck-boost type DC-DC converter is presented. Its voltage gain is positive, all active elements operate under soft-switching condition independent of loading, magnetic isolation and self output short-circuit protection exist, and very fast dynamic operation is achievable by a simple bang-bang controller. This converter also exhibits appropriate PFC characteristics since its input current is inherently proportional to the source voltage. When the voltage source is off-line, it is sufficient to add an inductor after the rectifier, then near unity power factor is achievable. All essential guidelines to design the converter as a DC-DC and a PFC regulator are presented. Simulation and experimental results verify the developed theoretical analysis.