• 전기의세계
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• v.21 no.1
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• pp.17-21
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• 1972

Electrical resistivity and switching phenomena in glass semiconductor of AsTe and AsTeGa is studied. Samples sliced from ingot which is air quenched or water quenched, show high resistivity at room temperature. The resistivity of the AsTe and AsTeGa is 1*10$^{6}$ .ohm.-cm and 5*10$^{6}$ .ohm.-cm at 27.deg. C. Switching phenomena take place in thin the thick samples. Holding voltage is different with the thickness of the samples and the characteristics of switching in the thin and thick samhles are similar. When square wave pulse voltage is applied, delay time is detected to 5.mu.sec by oscilloscpoe.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.11
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• pp.1707-1718
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• 2009

This study examines the effects of perceived risks on purchase decision behavior among Internet fashion consumers. The study survey used a self-administered questionnaire and a total data of 244 responses were used for analysis. The results of this study are as follows: First, the perceived risks consist of 6 factors, quality risk, counterfeit product risk, credit dealing risk, social/psychological risk, size and appearance risk, and delivery risk. The purchase decision behavior consist of 3 factors, delay of purchase decision, website switching, and offline conversion behavior. Second, purchase time positively affected the quality risk and credit dealing risk. Purchase frequency negatively affected the quality risk and credit dealing risk. Third, the quality risk, size and appearance risk, counterfeit product risk, and credit dealing risk positively affected the delay of purchase decisions. Quality risk and counterfeit product risk positively affected website switching. In addition, quality risk, social/psychological risk, and credit dealing risk positively affected the offline conversion behavior. Fourth, credit dealing risk negatively affected a short term purchase intention and the delivery risk negatively affected a long term purchase intention. The social/psychological risk and credit dealing risk negatively affected the repurchase intention.

• Journal of Communications and Networks
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• v.11 no.3
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• pp.297-305
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• 2009

Multiprotocol label switching (MPLS) networks require dynamic flow admission control to guarantee end-to-end quality of service (QoS) for each Internet protocol (IP) traffic flow. In this paper, we propose to tackle the joint routing and admission control problem for the IP traffic flows in MPLS networks without rerouting already admitted flows. We propose two mathematical programming models for this problem. The first model includes end-to-end delay constraints and the second one, end-to-end packet loss constraints. These end-to-end QoS constraints are imposed not only for the new traffic flow, but also for all already admitted flows in the network. The objective function of both models is to minimize the end-to-end delay for the new flow. Numerical results show that considering end-to-end delay (or packet loss) constraints for all flows has a small impact on the flow blocking rate. Moreover, we reduces significantly the mean end-to-end delay (or the mean packet loss rate) and the proposed approach is able to make its decision within 250 msec.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.2
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• pp.167-174
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• 2015

This study describes how digital time delay deteriorates control performance in zero voltage switching (ZVS) phase-shifted full bridge (PSFB) converter. The small-signal model of the ZVS PSFB converter is derived from the buck-converter small-signal model. Digital time delay effects have been considered according to the digital sampling methods. The analysis verifies that digital time delays reduce the stability margin of the converter, and the double sampling technique exhibits better performance than the single sampling technique. Both simulation and experimental results based on 250 W ZVS PSFB confirm the validity of the analyses performed in the study.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.11
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• pp.826-833
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• 1988

In this paper we studied the control of overload which could bring the degradation of performance and threaten the stability of the electronic switching system. In order to get the essential requirement for overload control algorithm, we tried to extract the characteristics of commonly used algorithms by means of simulating overload control alogrithms in numerical stored program control switching model. As the result, we could find that the overload control algorithm which monitored the CPU occupancy had the best call complete rate and good response characteristecs and the algorithm using the offered load as a system state variable had a good grade of service which was represented by a short dial tone delay and 3rd quartile of deal tone delay. however, these control algorithms have no generality and need to get the control parameters by the trial-and-error method. We suggested the guidelines on the design of the overload control algorithm.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.4
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• pp.188-200
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• 2001

This paper presents a technique for reconstructing converter line currents using the information from a single current sensor in the DC-link for voltage-source PWM converters. When three-Phase input currents cannot be reconstructed, three methods to acquire the input current are compared. Two of them are methods of modifying the switching state (I, II), another is a method of using the predictive state observer. Also, compensation of sampling delay, and a simultaneous sample value of input currents in the center of a switching period are included. Suitable criteria for the comparison are identified, and the differences in the performance of these methods are investigated through experimental results for a typical V-S PWM converter rated at 10kVA.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.4
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• pp.24-30
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• 1984

Group delay distortion (phase distortion) is a characteristic which is of no account from a standpoint of voice transmission. But this distortion becomes the major source of distortion in wave form transmission such as data, FAX and others over the public switching telephone network (voice band transmission) so that it must be drastically studied. This paper makes analysis of group deray distortion of the telephone network, describs experimental and measuring results and refers also to the improvement of distortion for the purpose of opening the public switching telephone network to data transmission.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1852-1854
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• 2003

In manufacturing processes, various and suitable pulse shapes are required for the purpose of material processing. In order to make various pulse shapes with variable pulse length and high duty cycle, We have fabricated the power supply consisting 6 SCRs and the Pulse Forming Network(PFN) with the precise delay time control. So our control system has three switching circuits, 3 mesh PFN, and simmer circuit. In addition, we have designed and fabricated the PIC one-chip microprocessor(16F877) to control the delay time of sequential switching.

• Journal of information and communication convergence engineering
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• v.9 no.6
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• pp.625-628
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• 2011

Dynamic sensor network(DSN) technology which is based on swarming flight type air node offers analyzed and acquired information on target data gathered by air nodes in rotation flight or 3 dimension array flight. Efficient operation of dynamic sensor network based on air node is possible when problems of processing time, data transmission reliability, power consumption and intermittent connectivity are solved. Delay tolerant network (DTN) can be a desirable alternative to solve those problems. DTN using store-and-forward message switching technology is a solution to intermittent network connectivity, long and variable delay time, asymmetric data rates, and high error rates. However, all processes are performed at the bundle layer, so high power consumption, long processing time, and repeated reliability technique occur. DSN based on swarming flight type air node need to adopt store-and-forward message switching technique of DTN, the cancelation scheme of repeated reliability technique, fast processing time with simplified layer composition.

• International Journal of Control, Automation, and Systems
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• v.5 no.5
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• pp.492-500
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• 2007

This paper focuses on the problem of guaranteed cost control for a class of uncertain linear delay systems with actuator failures. When actuators suffer "serious failure" the never failed actuators can not stabilize the system, based on switching strategy of average dwell time method, under the condition that activation time ratio between the system without actuator failure and the system with actuator failures is not less than a specified constant, a sufficient condition for exponential stability and weighted guaranteed cost performance are developed in terms of linear matrix inequalities (LMIs). Finally, as an example, a river pollution control problem illustrates the effectiveness of the proposed approach.