• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.1089-1095
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• 2005

This paper presents a new low-cost Built-In Self-Test (BIST) circuit for 50Hz low noise amplifier (LNA). The BIST circuit is designed for system-on-chip (SoC) transceiver environment. The proposed BIST circuit measures the LNA specifications such as input impedance, voltage gaih, noise figure, and input return loss all in a single SoC environment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.286-287
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• 2005

Critical current(Ic) degradation of HTS tapes and AC loss under mechanical load is one of the hottest issues in HTS development and application. Mechanical load reduces the critical current of superconducting wire, and the Ie degradation affects the AC loss of the wire. We measured the Ie degradation and AC loss under tension and bending of Bi-2223 tapes processed by "Powder-in-Tube" technique at 17K with self-field. And we have studied the frequency dependence of self-field AC loss in multi-filamentary Bi-2223/Ag tape at 77K. The measurement results and discussions on the relationship between Ic degradation and AC loss are presented.

• Progress in Superconductivity and Cryogenics
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• v.7 no.3
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• pp.29-33
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• 2005

Critical current$(I_c)$ degradation of High $T_c$ Superconducting(HTS) tapes and AC loss under mechanical load is one of the hottest issues in HTS development and application. Mechanical load reduces the critical current of superconducting wire, and the $I_c$ degradation affects the AC loss of the wire. We measured the $I_c$ degradation and AC loss under tension and bending of Bi-2223 tapes made by 'Powder-in-Tube' technique at 77K with self-field. Also, we have studied the frequency characteristics on self-field AC loss in multi-filamentary Bi-2223/Ag tape at 77K. The measurement results and discussions on the relationship between $I_c$ degradation and AC loss are presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.440-447
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• 2019

The purpose of this study was to identify the relationship between leisure function, self-esteem and social role loss among golf players in the middle age. Furthermore, it was meaningful to provide basic data on leisure activities and healthy retirement preparation through golf at the present time of the aging society. The subjects of study who adults were recruited from Seoul, Gyeonggi-do. For the data processing, it conducted frequency, reliability, confirmatory factor, correlation, and structure equaling modeling analyses. The results were as follows; First, leisure function of middle age golf participant had a positive influence on self-esteem(p<.05). Second, leisure function of middle age golf participant had a positive influence on social role loss(p<.05). Third, self-esteem of middle age golf participant had a positive influence on social role loss(p<.05). Forth, self-esteem mediated the relationship between middle age golf participant leisure function and social role loss.(p<.05).

• 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.

• Nutrition Research and Practice
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• v.14 no.1
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• pp.45-54
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• 2020

BACKGROUND/OBJECTIVES: This study aimed to examine differences in weight control practices, beliefs, self-efficacy, and eating behaviors of weight class athletes according to weight control level. SUBJECTS/METHODS: Subjects were weight class athletes from colleges in Gyeong-gi Province. Subjects (n = 182) responded to a questionnaire assessing study variables by self-report, and data on 151 athletes were used for statistical analysis. Subjects were categorized into High vs. Normal Weight Loss (HWL, NWL) groups depending on weight control level. Data were analyzed using t-test, ANCOVA, x²-test, and multiple logistic regressions. RESULTS: Seventy-three percent of subjects were in the HWL group. The two groups showed significant differences in weight control practices such as frequency (P < 0.01), duration and magnitude of weight loss, methods, and satisfaction with weight control (P < 0.001). Multiple logistic regression showed that self-efficacy (OR: 0.846, 95% CI: 0.730, 0.980), eating behaviors during training period (OR: 1.285, 95% CI: 1.112, 1.485), and eating behaviors during the weight control period (OR: 0.731, 95% CI: 0.620, 0.863) were associated with weight control level. Compared to NWL athletes, HWL athletes agreed more strongly on the disadvantages of rapid weight loss (P < 0.05 - P < 0.01), perceived less confidence in controlling overeating after matches (P < 0.001), and making weight within their weight class (P < 0.05). HWL athletes showed more inappropriate eating behaviors than NWL athletes, especially during the weight control period (P < 0.05 - P < 0.001). CONCLUSIONS: Self-efficacy was lower and eating behaviors during pre-competition period were more inadequate in HWL athletes. Education programs should include strategies to help athletes apply appropriate methods for weight control, increase self-efficacy, and adopt desirable eating behaviors.

• Korean Journal of Mathematics
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• v.11 no.1
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• pp.35-43
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• 2003

We study the weak convergence to Fractional Brownian motion and some examples with applications to traffic modeling. Finally, we get loss probability for queue-length distribution related to self-similar process.

• Journal of Digital Contents Society
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• v.5 no.1
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• pp.7-11
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• 2004

There are many problems that must solve to construct next generation high-speed communication network. Among these, item that must consider basically is characteristics analysis of traffic that nows to network Traffic characteristics of many Internet services that is offered present have shown that network traffic exhibits at a wide range of scals-self-similarity. Self-similarity is expressed by long term dependency, this is contradictory concept with Poisson model that have relativity short term dependency. Therefore, first of all, for design and dimensioning of next generation communication network, traffic model that are reflected burstiness and self-similarity is required. Here self-similarity can be characterized by Hurst parameter. In this paper, the calculation equation is derived considering queueing delay and self-similarity of data traffic art compared with simulation results.

• Journal of Power Electronics
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• v.16 no.1
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• pp.121-132
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• 2016

In this paper, high-efficiency design methodology of a zero-voltage-switching full-bridge (ZVS-FB) pulse width modulation (PWM) converter for server-computer power supply is discussed based on self-driven synchronous rectifier (SR) performance. The design approach focuses on rectifier conduction loss on the secondary side because of high output current application. Various-number parallel-connected SRs are evaluated to reduce high conduction loss. For this approach, the reliability of gate control signals produced from a self-driver is analyzed in detail to determine whether the converter achieves high efficiency. A laboratory prototype that operates at 80 kHz and rated 1 kW/12 V is built for various-number parallel combination of SRs to verify the proposed theoretical analysis and evaluations. Measurement results show that the best efficiency of the converter is 95.16%.

• Journal of the Korean Society of Combustion
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• v.17 no.1
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• pp.37-47
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• 2012

Experimental study on comparison of diffusive-thermal self-excitation with buoyancy-driven one due to accumulation of partially premixed, preheated mixture in front of edge flame was conducted in horizontally and vertically injected laminar free-jet flames with an applied DC electric field of -10 kV. The application of horizontal injection method with the DC electric field to jet flames was experimentally designed to suppress heat-loss-induced self-excitation and thereby to highlight the definite difference between both diffusive-thermal and buoyancy-driven self-excitations with the same order of O(1.0 Hz), in that diffusive-thermal self-excitation has not been so far found experimentally in laminar jet flames. Flame stability maps in vertically and horizontally injected jet flames are presented. The distinct modes of individual self-excitation are shown to be well described by their own phase diagrams. The results show that buoyancy-driven self-excitation due to the accumulation of partially premixed, preheated mixtures in front of edge flame is branched from the buoyancy-induced self-excitation with O(10 Hz) due to a flame flicker. Once the buoyancy-driven self-excitation appears, it suppresses buoyancy-induced as well as diffusive-thermal self-excitation. The key characteristics for individual self-excitation are discussed and their functional dependencies of Strouhal number upon related physical parameters are also presented.