• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.264-267
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• 2002

This paper presents the design of a pipelined virtual output queue routing engine for an advanced input-queued ATM switch, which has a serial cross bar structure. The proposed routing engine has been designed for wire-speed routing with a pipelined buffer management. It provides the tolerance of requests and grants data transmission latency between the routing engine and central arbiter using a new request control method that is based on a high-speed shifter. The designed routing engine has been implemented in a field programmable gate array (FPGA) chip with a 77MHz operating frequency, 16$\times$16 switch size, and 2.5Gbps/port speed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.84-88
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• 2001

Security and degradation by broadcast is the most important part that must handle in LAN. Virtual LAN can improve LAN's degradation by method to form and manages network group logically. MAC Address VLAN algorithm that propose in this research give overlap special qualify to VLAN adding extension VID field and VID connection extent table to FDB, manage overlap extent dynamically. VLAN that apply this proposal algorithm can share information and resource in network without additional equipment. Application is possible switch or Bridge that this algorithm achieves Layer 2 functions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2B
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• pp.120-130
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• 2011

Recently the multicast based contents transmission is rapidly increasing due to the various multimedia services and the importance of switching technology to handle it is increasing as a consequence. Though the CICQ architecture has advantages that reduction of HoL blocking probability and simple scheduling using cross point buffer, it has disadvantage that the processing rate of multicast traffic can be significantly degraded corresponds to the traffic load increment. Several schemes have been proposed to solve this problem however they still can't provide enough processing ratio for multicast traffic. Therefore this paper proposes the BA cell assignment scheme and the VT scheme, and the processing rate of multicast traffic can be guaranteed by reducing the HoL blocking probability of multicast traffic and reservation of cross point buffer. Also simulation results verify that using the proposed scheme, the QoS of multicast service can be improved.

• Asia pacific journal of information systems
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• v.16 no.3
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• pp.67-93
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• 2006

Some consumers prefer online and others prefer offline. What makes them prefer online or offline? There has been a lack of theoretical development to adequately explain consumers' channel switching behavior between traditional physical stores and new virtual stores. Through consumers' purchase decision processes, this study examined the reasons why consumers changed channels depending on purchase process stages. Consumer's purchase decision process could be divided into three stages: pre-purchase stage, purchase stage, and post-purchase stage. We used the intention of channel selection as a surrogate dependent variable of channel selection. And some constructs, that is, channel function, channel benefits, customer relationship benefits, and perceived behavioral control, were selected as independent variables. In buying look-and-feel products, it was identified that consumers preferred virtual stores to physical stores at pre-purchase stage. To put it concretely, all constructs except channel benefits were more influenced to consumers at virtual stores. This result implied that information searching function, which is a main function at pre-purchase stage, was better supported by virtual stores than physical stores. In purchase stage, consumers preferred physical stores to virtual stores. Specially, all constructs influenced much more to consumers at physical stores. This result implied that although escrow service and trusted third parties were introduced, consumers felt that financial risk, performance risk, social risk, etc. still remained highly online. Finally, consumers did not prefer any channel at post-purchase stage. But three independent variables, i.e. channel function, channel benefits, and customer relationship benefits, were significantly preferred at physical stores rather than virtual stores at post-purchase stage. So we concluded that physical stores were a little more preferred to virtual stores at post-purchase stage. Through this study, it was identified that most consumers might switch channels according to purchase process stages. So, first of all, sales representatives should decide that what benefits should be given them through virtual stores at the pre-purchase stage and through physical stores at the purchase and post-purchase stages, and then devise collaborative channel strategies.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.8
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• pp.833-842
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• 2011

The objectives of this research are development of guidance, navigation and control system for RUAV on virtual instrumentation and real flight test. For this research, the system is divided to DAQ (data acquisition) section, actuator section and controller section. And the hardware and software on each sections are realized on LabVIEW base. Waypoint guidance and control of auto flight are realized using PID gain tuning and waypoint vector tracking guidance algorism. For safe flight test, auto/manual switching module isolated from FCS (Flight Control System) is developed. By using the switch module, swift mode change was achieved during emergency flight case. Consequently, a meter level error of flight performance is achieved.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.11
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• pp.27-33
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• 2003

This paper proposes the efficient audit method for the distributed connection information in ATM switch. Based on this method, we design the periodic audit function by a system and immediate audit function by a operator's order. We evaluate the performance about the proposed Audit method. At the result of evaluation, We figure out that the load of call control processor is almost independent of a system load regardless of audit function operation. Therefore, we confirm that the proposed audit method nearly have an effect on the load of call control processor. The proposed audit method can reestablish a Mismatched connection information with a little load.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.6
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• pp.1323-1333
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• 1997

In this paper, we propose an efficient architecture for a high-speed cell concentrator/distributor(HCCD) in an ATM(Asynchronous Transfer Mode) switch and by analyzeing the simulation results evaluate the performance of the proposed architecuture. The proposed HCCD distributes cells from a switch link to local processors, or concentrates cells from local processor s to a switch link. This design is to guarntee a high throughput for the IPC (inter-processor communication) link in a distributed ATM switching system. The HCCD is designed in a moudlar architecture to provide the extensibility and the flexibility. The main characteristics of the HCCD are 1) Adaption of a local CPU in HCCD for improving flexibility of the system, 2) A cell-baced statistical multiplexing function for efficient multiplexing, 3) A cell distribution function based on VPI(Virtual Path Identifier), 4) A bypassing capability for IPC between processor attached to the same HCCD, 5) A multicasting capability for point-to-multipoint communication, 6) A VPI table updating function for the efficient management of links, 7) A self-testing function for detecting system fault.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3435-3454
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• 2016

Device-to-device (D2D) communication is a potential solution to the incessant increase in data traffic on cellular networks. The greatest problem is how to control the interference between D2D users and cellular mobile users, and between D2D users themselves. This paper proposes a solution for this issue by putting the full control privilege in cellular network using the software-defined networking (SDN) concept. A software virtual switch called Open vSwitch and several components are integrated into mobile devices for data forwarding and radio resource mapping, whereas the control functions are executed in the cellular network via a SDN controller. This allows the network to assign radio resources for D2D communication directly, thus reducing interference. This solution also brings out many benefits, including resource efficiency, energy saving, topology flexibility, etc. The advantages and disadvantages of this architecture are analyzed by both a mathematical method and a simple implementation. The result shows that implementation of this solution in the next generation of cellular networks is feasible.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1416_1417
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• 2009

This paper shows the characteristic of wave tail according to inductance values in 10/$350{\mu}s$ impulse circuit with crowbar switch. The PSpice was used to simulate the 10/$350{\mu}s$ current waveform and lightning current impulse generator was used to generate real current waveform. As a capacitor of condenser bank increases, a virtual front time increases and a time to half-value decreases. To get a perfect 10/$350{\mu}s$ current waveform, we should consider the combination of circuit values of the inductance, capacitance, time difference between trigger pulses and charged voltage of capacitor bank.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.6A
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• pp.1060-1066
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• 2001

레이어2 스위칭과 레이어3 라우팅의 통합 모델로써 MPLS(Multi-Protocol Label Switching) 환경에서 ATM LSR(Label-Switching Routers)은 백본망에서의 고속 전송이 가능하여 현재의 라우터 구조로써 제안되어지고 있다. MPLS가 코어 라이터로써 적용이 될 경우 확장성을 위해 label merging이라는 기술이 필요하다. VC(Virtual Circuit) merging은 ATM LSR에서 많은 IP 라우터를 하나의 라벨로 매핑을 시키며 수천 개의 목적지에 전송할 수 있는 확장성 있는 매핑 기술이다. VC merging은 같은 목적지인 다른 패킷들 간의 셀들의 섞임을 방지하기 위해 재 조합 버퍼가 요구된다. 재 조합 버퍼 사용시 일시적인 체증 현상이 발생하며 Non-VC merging과 비교시 많은 셀 손실과 많은 버퍼를 요구하게 된다. 본 논문에서는 RED(Random Early Detection) 알고리즘을 적용하여 VC merging이 필요한 버퍼의 요구량과 셀 손실을 줄였다.