• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.1 s.343
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• pp.111-120
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• 2006

In this paper, a node architecture of WDM metro network for connecting broadband access networks to converge wire/wireless networks. In consideration of the proposed node architecture and network requirements we proposed and evaluated medium access control protocols. We review WDM related technologies of sub-carrier multiplexing and optical components in order to resolve the bottleneck between optical backbone networks md access networks, and a access node architecture sharing common wavelength is introduced. Source-stripping (SS) MAC protocol Is evaluated under the proposed functional node architecture. DS+IS (Destination-Stripping and Source-Stripping) and DS+IS (Destination-Stripping and Intermediate-Stripping) MAC protocols are described to increase the slot-reuse factor which is low on SS MAC protocol. The key function of new MAC protocols regards the optical switch module of proposed node architecture and helps intermediate or source access nodes for dropping slots to destinations of different wavelength group. Thus, slot-reuse factor increases as the MAC protocols reduce the unnecessary ring-rotation of transferred slots. We use a numerical analysis to expect bandwidth efficiency and maximum throughput by slot-reuse factor Throughput network simulation, the verification of throughput, queuing delay, and transmission fairness are compared among MAC protocols.

• Journal of Broadcast Engineering
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• v.7 no.3
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• pp.211-218
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• 2002

This paper introduces the HD 3DTV camera and 3DTV receiver that are compatible with the ATSC HDTV broadcasting system. The developed 3DTV camera is based on stereoscopic techniques, and it has control function to control both left and right zoom lens simultaneously and to control the vergence. Moreover, in order to control the vergence manually and to eliminate the synchronization problem of the both images, the 3DTV camera has the 3DTV video multiplexing function to combine the left and right images into the single image. The developed 3DTV signal, and it has the various analog/digital interfaces. The performance of the developed system is confirmed by shooting the selected soccer game in 2002 FIFA KOREA/JAPANTM World Cup and by broadcasting the match. The HD 3DTV camera and receiver will be applied to the 3DTV industries such as 3D movie, 3D game, 3D image processing, 3DTV broadcasting system, and so on.

• Industry Promotion Research
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• v.2 no.2
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• pp.1-6
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• 2017

SCADA (Supervisory Control and Data Acquisition) System was first introduced to the Seoul Electricity Authority, which manages the transportation part among the three business fields that produce, transport and supply electric power in Korea. Has been using the data link with 1200 bps and 9600 bps in 5 protocols such as HARRIS 6000, BSC, HDLC, L & N and Toshiba by configuring 3 layers of EMS, SCADA and RTU computer equipments in 1: N radial form. This paper presents the OSI standard network packet flow, analyzing DataLink and Network Layer, and presents a KEPCO SCADA network model composed of X.25 high - speed communication network using 3 layers of network. We proposed a future SCADA communication structure that improved the current SCADA communication structure, defined the SCADA DB structure, introduced the concept of the remote SCADA gateway to the SCADA functional structure, applied the standard communication protocol, Multiplexing of surveillance and control in other local facilities and ensuring communication openness.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.328-338
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• 2017

In this paper, a zero torque control scheme adopting current sharing function (CSF) used in integrated Switched Reluctance Motor (SRM) drive with DC battery charger is proposed. The proposed control scheme is able to achieve the keeping position (KP), zero torque (ZT) and power factor correction (PFC) at the same time with a simple novel current sharing function algorithm. The proposed CSF makes the proper reference for each phase windings of SRM to satisfy the total charging current of the battery with zero torque output to hold still position with power factor correction, and the copper loss minimization during of battery charging is also achieved during this process. Based on these, CSFs can be used without any recalculation of the optimal current at every sampling time. In this proposed integrated battery charger system, the cost effective, volume and weight reduction and power enlargement is realized by function multiplexing of the motor winding and asymmetric SR converter. By using the phase winding as large inductors for charging process, and taking the asymmetric SR converter as an interleaved converter with boost mode operation, the EV can be charged effectively and successfully with minimum integral system. In this integral system, there is a position sliding mode controller used to overcome any uncertainty such as mutual inductance or DC offset current sensor. Power factor correction and voltage adaption are obtained with three-phase buck type converter (or current source rectifier) that is cascaded with conventional SRM, one for wide input and output voltage range. The practicability is validated by the simulation and experimental results by using a laboratory 3-hp SRM setup based on TI TMS320F28335 platform.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.842-849
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• 2000

In this paper, We analyzed the protocol to improve the performance of the multicast traffic processing in WDM networks. In the protocol, control channels are devided into contention-less minislots and contention minislots. And the packets which fail to have successful reservation in the present time slot have priority to have successful reservation in the contention-less minislots of the next time slot. Therefore, control channel contentions and destination conflicts can be reduced with the use of contention-less minislots. For the multicast traffic processing, the theoretical analysis and computer simulation are important to estimate the network performance and to calculate the optimized number of contention-less minislots. In this paper, the state transition probability of the number of contention-less minislots and arrival packets are calculated using 4-dimension matrix. The maximum number of contention-less minislots is equal to the number of channels for maximum performance improvement of the system. It is theoretical analysis and prove to computer simulation the performance of the protocol.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.9 s.339
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• pp.71-84
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• 2005

A 'VPN over Intemet' has the benefit of being cost-effective and flexible. However, it has difficulties providing sufficient QoS and adequate transmission capacity for high bandwidth service. Given the increasing demand for high bandwidth Internet and QoS assurances in a 'VPN over Internet', IP/GMPLS based on a control plane combined with a high bandwidth, DWDM optical network is seen as a very favorable anroach for realizing the future 'OVPN over IP/GMPLS over DWDM'. Within this architecture, providing QoS guaranteed multimedia services with a differentiated QoS guaranteed protocol framework with QoS recovery is one of the key issues to implement. Therefore, in this paper, we suggest the entire interoperability procedure of control protocols based on differentiated optical QoS service (DOQOS) classes for providing end-to-end QoS in an 'OVPN over IP/GMPLS over DWDM' architecture.

• Convergence Security Journal
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• v.21 no.1
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• pp.25-31
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• 2021

The purpose of this study was to keep the Security Control Center, which operates under a shift system, uninterrupted during the COVID-19 virus epidemic. Security facilities responding to cybersecurity threats are essential security facilities that must be operated 24 hours a day, 365 days a day in real time, and are critical to security operations and management. If security facilities such as infectious disease epidemic, system failure, and physical impact are closed or affected, they cannot respond to real-time cyberattacks and can be fatal to security issues. Recently, there have been cases in which security system facilities cannot be operated, such as the closure of facilities due to the COVID-19 virus epidemic and the availability of security systems due to the rainy season, and other cases need to be prepared. In this paper, we propose a plan to configure a security system facility as a multiplexing facility and operate it as an alternative in the event of a closed situation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.1
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• pp.131-143
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• 1996

In this paper, we propose the improved structure of fully interconnected ATM Switch to develop the small sized switch element and represent practical implementation of switch network. As the part II of the full study about structure and implementation of fully interconnected ATM Switch, this paper especially describes the implementation of an ATM switching element with 8 input port and 8 output port at 155 Mbits/sec each. The single board switching element is used as a basic switching block in a small sized ATm switch for ATM LAN Hub and customer access node. This switch has dedicated bus in 12 bit width(8 bit data + 4 bit control signal) at each input and output port, bit addressing and cell filtering scheme. In this paper, we propose a practical switch architecture with fully interconnected buses to implement a small-sized switch and to provide multicast function withoutany difficulty. The design of switching element has become feasible using advanced CMOS technology and Embedded Gate Array technology. And, we also represent Application Specific Integrated Circuit(ASIC) of Switch Output Multiplexing Unit(SOMU) and 12 layered Printed Circuit Board for interconnection network of switch.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.568-570
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• 2002

With the development of Wavelength Division Multiplexing (WDM) and Optical Cross-Connect (OXC) systems, an efficient integration of IP and WDM has been focused. The Optical Internetworking Forum (OIF) proposes a new model that is called Overlay model for the integration of IP and WDM. In the Overlay model, UNI 1.0 signaling is adopted to establish signaling interface between Optical and IP network. UNI 1.0 signaling consists of a lot of functions; especially, reliability, light traffic, and etc. For that reason, Srefresh and ACK messages in UNI signaling support reliable messaging and reduce the amount of information that must be transmitted and processed in order to maintain RSVP states and processing time. This paper focuses on an implementation of Srefresh and ACK messages based on UNI 1.0 signaling and comparison between before and after implementing. The results show that Srefresh and ACK messages improve intelligence in the control plane of the optical network, which will make them more survivable, flexible, reliable, and controllable.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3A
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• pp.160-167
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• 2005

The gain-clamped EDFA has been developed to eliminate the output power change of WDM surviving channels to occur with added or dropped channels, which degrades the performance of WDM optical network. It maintains the constant gain of surviving channels when WDM channels are added or dropped in a network amplifying node. In this paper, the hi-directionally pumped gain-clamped EDFA is implemented to compensate the change of the input power by a lasing. The results show that the lasing of a short wavelength and backward propagation is the optimal condition to minimize the transient response of surviving channels in terms of the overshoot and gain saturation due to the inhomogeneous broadening effect.