• Journal of Digital Contents Society
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• v.3 no.1
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• pp.89-99
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• 2002

Saturation routing algorithm is known to be an effective routing mechanism for tactical application and packet radio networks, since it minimizes the call set-up time and does not have to maintain routing tables. But, it is known that it has significant drawbacks with respect to the network efficiency, the overhead on the control messages [1]. We consider a tactical circuit-switched grid network with a maximum of tour links and two priority classes of voice traffic. Using the minimum first-derivative length (MFDL) path, we improve the blocking probability performance of a circuit-switched network without increasing the call set-up time and processor loading of the algorithm.

• ETRI Journal
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• v.22 no.3
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• pp.1-9
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• 2000

Self-Clocked Fair Queueing (SCFQ) algorithm has been considered as an attractive packet scheduling algorithm because of its implementation simplicity, but it has unbounded delay property in some input traffic conditions. In this paper, we propose a Rate Proportional SCFQ (RP-SCFQ) algorithm which is a rate proportional version of SCFQ. If any fair queueing algorithm can be categorized into the rate proportional class and input is constrained by a leaky bucket, its delay is bounded and the same as that of Weighted Fair Queueing (WFQ) which is known as an optimal fair queueing algorithm. RP-SCFQ calculates the timestamps of packets arriving during the transmission of a packet using the current value of system potential updated at every packet departing instant and uses a starting potential when it updates the system potential. By doing so, RP-SCFQ can have the rate proportional property. RP-SCFQ is appropriate for high-speed packet-switched networks since its implementation complexity is low while it guarantees the bounded delay even in the worst-case input traffic conditions.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.2
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• pp.55-60
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• 2008

Packet-switched wavelength division multiplexing (WDM) ring networks have been extensively studied as solutions to the increasing amount of traffic in metropolitan area networks, which is widely expected to be a mix of unicast and multicast traffic. In this paper we study the fairness between unicasting and multicasting in slotted packet-switched WDM ring networks that employ a tunable transmitter and fixed tuned receiver at each node and a posteriori buffer selection. We find that single-step longest queue selection algorithm generally results in unfairness between unicasting and multicasting or a lilted relative priority for multicast vs. unicast traffic. We present the various virtual output queue structures and their performance.

• Journal of Korean Institute of Industrial Engineers
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• v.30 no.3
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• pp.213-223
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• 2004

We consider the traffic grooming problem for the design of SONET/WDM(Synchronous Optical NETwork/Wavelength Division Multiplexing) ring networks. Given a physical network with ring topology and a set of traffic demands between pairs of nodes, we are to obtain a stack of rings with the objective of minimizing the number of ADMs installed at the nodes. This problem arises when a single ring capacity is not large enough to accommodate all the demands. As a solution method, an efficient algorithm based on the branch-and-price approach has been reported in the literature for the problem in which only unidirecional path switched ring (UPSR) was considered. In this study, we suggest integer programming models and the algorithms based on the same approach as the above one, considering two-fiber bidirectional line switched ring(BLSR/2), and BLSR/4 additionally. Using the results, we compare the number of required ADMs for all types of the ring architecture.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6B
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• pp.538-547
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• 2004

Optical Burst Switched (OBS) networks usually employ one-way reservation by sending a burst control packet (BCP) with a specific offset time, before transmitting each data burst frame (BDF). Therefore, The quality of service may be degraded because contentions may lead to loss of BDFs. Especially, this phenomenon becomes more serious when burst size is longer. This necessitates an effective method of prevention to avoid burst collision in nodes. OBS networks can employ several methods to avoid such burst losses. One is that burst size is cut short to reduce burst loss probability during scheduling time. In this paper, we evaluate the burst generation and transmission using Sub-Carrier Multiplexting (SCM) in OBS networks. We propose an appropriate burst assembly architecture and transmission scheme based on SCM in OBS networks. The performance of SCM in OBS networks is examined in terms of number of Sub-Carriers per wavelength, burst loss probability, throughput, and total bandwidth of an optical fiber.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.3
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• pp.360-371
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• 1993

Flood search algorithm is known to be an effective routing mechanism for tactical application, since it provides high degree of survivability and robustness. But it is known that it has significant drawbacks with respect to the network efficiency [1]. We consider a tactical circuit-switched grid network with a maximum of four links and two priority classes of voice traffic, Using the minimum first-derivative length (MFDL) path, we improve the blocking probability performance of the circuit-switched network without increasing the call set-up time and processor loading of the algorithm.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1735-1742
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• 2016

This paper proposes an interleaved five-level boost converter based on a switched-capacitor network. The operating principle of the converter under the CCM mode is analyzed. A high voltage gain, low component stress, small input current ripple, and self-balancing function for the capacitor voltages in the switched-capacitor networks are achieved. In addition, a three-loop control strategy including an outer voltage loop, an inner current loop and a voltage-balance loop has been researched to achieve good performances and voltage-balance effect. An experimental study has been done to verify the correctness and feasibility of the proposed converter and control strategy.

• Information and Communications Magazine
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• v.21 no.7
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• pp.117-132
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• 2004

이동 통신 시스템의 최종적인 목표는 광범위 한 사용을 위하여 정보통신 서비스에 대한 유비 쿼터스 접근을 제공하기 위한 것이다. 이 목적을 달성하기 위하여, 여러 가지 많은 기술적인 문제들이 극복되어야 하지만, 그 중에서도 특히 비 인가된 사용자로부터 네트워크와 가입자 자원을 보호하는 것이 매우 중요한 과제 중의 하나이다. 이러한 보호는 네트워크에서 비밀성, 인증 및 접근 제어를 통하여 실현될 수 있다. 따라서 본 고체서는 이 문제에 대하여 기술하고자 한다［10］. 보안은 공중 교환 전화망(PSTN: Public Switched Telephone Networks), 근거리 통신망(LAN: Local Area Networks)과 같은 유선통신시스템에서 보다 무선 통신시스템에서 더욱 중요한 역할을 차지한다.(중략)

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1794-1803
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• 1989

This paper presents and evaluates a distributed routing algorithm for effective routing control in circuit-switched multistage interconnection networks. The proposed method uses the distributed control based on the incividual-switching element control and it is very effective for allowing any broadcast connection from a source to arbitrary number of destinadtions. The performnace of the proposed method is analyzed and evaluated by computer simulation in terms of the normalized average time delays.

• Electronics and Telecommunications Trends
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• v.35 no.6
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• pp.68-77
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• 2020

Along the advancement of mobile networks, fixed telephone networks are gradually advancing from legacy networks based on copper and circuit-switches to optical cables and packet-switched IP networks. Incumbent fixed-line telephone operators are facilitating the introduction of IP networks and are gradually converting to IP-based facilities according to the investment plans for each operator. As the PSTN's IP conversion exceeds a certain level and VoIP; (an alternative service); is activated, some countries; such as Europe; are considering terminating the PSTN service, centering on operators. In this paper, trends in the procedure, timing, and major issues related to the termination of an overseas PSTN are examined. The domestic status is also examined.