• Journal of Korean Library and Information Science Society
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• v.14
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• pp.149-179
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• 1987

The concept of a "switching language " between different indexing languages and information retrieval systems has been discussed since the mid-1960s. Some preliminary investigates into the feasibility of switching between mediating tool yielded positive results. The Broad system of ordering(BSO) , a general classification scheme for information exchange and switching, has been under development as a joint FID/UNESCO project since 1973. The purpose of this study is to find out the origin, development, definition, and principle of BSO. The results of the study can be summarized as follows: (1) BSO is a switching language for the purpose of interconnection of information system which is located different regions, or using different indexing languages. (2) BSO is in effect, fully faceted and broad classification system. (3) BSO is not only a subject code but also an ordering system. (4) BSO can be used information retrieval system because the notation of composite subjects is formed by combining notation. (5) BSO has to some extent sacrificed brevity by leaving large unused notational gap for future use. (6) The structure of the scheme is in no way dependent upon the notation. notation.

• Proceedings of the KIPE Conference
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• 1998.11a
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• pp.39-43
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• 1998

A large number of soft switching topologies included a resonant circuit have been proposed. But these circuits increase number of switch in circuit and complicate sequence of switching operation. In this paper, the authors propose power conversion system, DC-AC inverter of high efficiency and high power factor with soft switching mode by partial resonant method. The switching devices in a proposed circuits are operated with soft switching by the partial resonant method, that is, PRS2MPC (Partial Resonant Soft Switching Mode Power Converter). The result is that the switching loss is very low and the efficiency of system is high. And the snubber condenser used in partial resonant circuit makes charging energy regenerated at input power source for resonant operation.

• ETRI Journal
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• v.17 no.1
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• pp.23-36
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• 1995

We present a performance evaluation model of cell reassembly mechanism in an ATM switching system. An ATM switching system may be designed so that communications between processors of its control part can be performed via its switching network rather than a separate inter-processor communications network. In such a system, there should be interface to convert inter-processor communication traffic from message format to cell format and vice versa, that is, mechanisms to perform the segmentation and reassembly sublayer. In this paper, we employ a continuous-time Markov chain for the performance evaluation model of cell reassembly mechanism with individual buffering, judicially defining the states of the mechanism. Performance measures such as message loss probability and average reassembly delay are obtained in closed forms. Some numerical illustrations are given for the performance analysis and dimensioning of the cell reassembly mechanism.

• Journal of Power Electronics
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• v.15 no.6
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• pp.1480-1488
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• 2015

In this paper, a revolutionary buck converter is proposed with soft-switching technology, which is realized by a coupled inductor. Both zero-voltage switching (ZVS) of main switch and zero-current switching (ZCS) of freewheeling diode are achieved at turn on and turn off without using any auxiliary circuits by the resonance between the parasitic capacitor and the coupled inductor. Furthermore, the peak voltages of the main switch and the peak current of the freewheeling diode are significantly reduced by the coupled inductor. As a result, the proposed converter has the advantages of simple circuit, convenient control, low consumption and so on. The detailed operation principles and steady-state analysis of the proposed ZVS-ZCS buck converter are presented, and detailed power loss analysis and some simulation results are also included. Finally, experimental results based on a 200-W prototype are provided to verify the theory and design of the proposed converter.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.3
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• pp.76-81
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• 2002

In high power motor drive system, the hard-switching topology produces severs switching losses and EMI noises. Also the inverter switching frequency is thus limited because of excessive loss and thermal handling problem. The primary purpose of the proposed works on the induction motor drive system is to develop an advanced soft-switching inverter topology that is most suitable for high power induction motor drive applications. To make the optimal selection EMI comparison of the switching losses presented. To verify the proposed design procedure, detailed simulation analysis with theoretical and experimental approaches have been done using laboratory prototype.

• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.11-19
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• 2018

In the Unmanned Aerial Vehicle Line-Of-Sight datalink system, there is a possibility that the communication line is disconnected because line of sight can not be secured by one antenna due to changes in position and posture of the air vehicle. In order to prevent this, both top and bottom of air vehicle are equipped with antennas. At this time, if the signal can be transmitted and received by switching to an antenna advantageous for securing the line of sight, communication disconnection can be minimized. The legacy antenna switching method has disadvantages such that diffraction, fading due to the surface or obstacles, interference and reflection of the air vehicle are not considered, or antenna switching standard is not clear. In this paper, we propose an airborne antenna switching method for improving the performance of UAV LOS datalink system. In the antenna switching method, the performance of each of the upper and lower parts of the mounted antenna according to the position and attitude of the air vehicle is predicted by using the deep learning in an UAV LOS datalink system in which only the antenna except the receiver is duplicated. Simulation using flying test dataset shows that it is possible to switch antennas considering the position and attitude of unmanned aerial vehicle in the datalink system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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• pp.744-749
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• 2013

The protection switching technology is widely adopted in the fiber-optical transmission equipments based on TDM(Time Division Multiplexing), such as PDH, SDH/SONET. A variety of protection switching algorithms for Ethernet networks and the progress of standardization are summarized in the document. There are several kinds of protection switching algorithms for Ethernet networks, such as STP, RSTP, MSTP and etc. However, since Ethernet signal move through detour route, it causes much time to recover. Accordingly, it is difficult to secure a usability of Ethernet networks and QOS(Quality of Service). Also, if the protection switching protocol standardized by IEEE and ITU-T is used, it remains a inherent network switching time for protection. Therefore, a specific protection switching algorithm for Ethernet are needed for seamless and stable operation of Ethernet networks service for Distribution Automation System(DAS). A reliable protection algorithm with no switching delay time is very important to implement Self-healing service for DAS. This study of FPGA based protection switching algorithm for Ethernet networks shows that in case of faults occurrence on distribution power network, immediate fault isolation and restoration are conducted through interaction with distribution equipments using P2P(Peer to Peer) communication for protection coordination. It is concluded that FPGA based protection switching algorithm for Ethernet networks available 0ms switching time is crucial technology to secure reliability of DAS.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.411-414
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• 1989

It is well known that switching overvoltages in the electric power system can damage electric power apparatus. To investigate switching overvoltages, electric power system has been modeled using mathematical equal ions. Using developed model, switching overvoltages in the transformer terminal have been computed and analysed.

• Journal of Korean Institute of Industrial Engineers
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• v.35 no.2
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• pp.171-177
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• 2009

This study presents the switching strategy between admission control and pricing control policies and clarifies the properties of the switching strategy in an M/M/1/K queueing system. In addition, this study demonstrates that employing the switching strategy can significantly improve the maximum total expected profit.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.356-356
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• 2000

For irregular nonlinear systems, switching controlk form is proposed recently. This control law is designed to overcome the singularities through the scheme that switches between an approximate tracking law close to the singularities, and an exact tracking law away from the singularities. But, that form has problems which may break the system's stability through unstable control input value at switching procedure. In this paper, We propose new switching control law which supervises approximate tracking control law and exact tracking control law by fuzzy rules to overcome unstability problem in switching procedure.