• Electronics and Telecommunications Trends
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• v.14 no.1 s.55
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• pp.36-52
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• 1999

본 고에서는 ATM 통신망에서 시험의 필요성, 종류 및 방법 그리고 시험 시스템의 기능 등에 대해서 기술하였다. ATM은 보다 높은 속도를 제공하고 통신망의 QoS(Quality of Service)를 제어하며 보다 효율적으로 통신망 자원을 사용할 수 있는 방법을 제공한다. 그러나 이러한 모든 서비스를 만족시키기 위해서는 신뢰성이 필요한데 큰 용량과 복잡한 특성을 갖는 ATM 통신망은 서비스 열화와 고장에 매우 민감하다. 이를 해결하기 위한 최선의 방법이 ATM 구성요소와 시스템 수준에서 엄격하고 표준화된 시험을 통해서 이루어진다. 본 고에서는 여러 국제 표준화 기관에서 ATM 통신망에 대한 시험의 표준화 동향에 대해서 기술하였다. 또한 표준화된 시험 방법을 수행하기 위해서 시험 수행방법과 통신망 및 시험 시스템에 대한 문제점을 기술하였으며, 이러한 문제점을 극복하기 위한 시험 자동화, 효율적인 시험 방법 등에 대해서도 기술하였다. 또한 ATM 통신망 시험에서 많이 사용되는 시험 시스템의 기능을 분류하고 시험실 수준의 테스트베드(testbed) 구축방법을 제안하였다.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.94-97
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• 1999

In this paper, a new real-time neural network connection admission controller is proposed. The proposed controller measures traffic flows, cell loss rate and cell delay periodically each classes. The Neural network learns the relation between those measured information and service quality by real-time. Also the proposed controller uses the DWRR multiplexer with buffer dedicated to every traffic source in order to measure the delay that cells experience in buffer. Experimental result shows that the proposed method can control effectively heterogeneous traffic sources with diverse QoS requirement.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.9
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• pp.12-20
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• 2001

The ATM-PON has an important meaning at next generation access network because the equipment transmits various types of user traffic with a single platform through the passive optical splitter. Ranging is a technology to place all ONUs at the same virtual distance in order to provide the synchronization for the upstream signal in the ATM-PON based on the Time Division Multiplexing (TDM). In this paper, we review the merits of ATM PON and related protocol for the PON operation. We summarize and analyze the steps about the ranging protocol based on ITU-T G.983.1 and implement a simulator that can simulate the ranging procedure based on our modeling. In this paper, we can investigate time requirements of G.983.1 by using the simulator and find out the wasted rate of the bandwidth during the ranging procedure in order to know the influence for ONUs while ATM-PON is in-service. Also, we show that a new ranging scheme reducing window size can avoid the degradation of quality of service of ONUs in service with simulation.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.10
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• pp.30-39
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• 1999

In this paper, the size of IWU frame cell buffer is analyzed that receives FR frame cells from other FR networks through ATM backbone network. The frame cell buffer receives multiplexed ATM cells from other IWUs that provide interworking with ATM network for other FR networks A receiving IWU reassembles frames from multiplexed ATM cells by identifying the VPI/VCIs. The reassembled frames are transmitted on FR network links according to their destination. Therefore, IWU needs sufficient amount of buffers for the assembly of the frames and for providing the assembled frames with the queue to wait until the frame is transmitted by FR network link. In this paper, the probability of frame loss at the frame cell buffer is derived in terms of traffic parameters, the number of multiplexed FR connections, the number of FR links and the transmission capacity. By applying the derived results, we analyzed the required buffer size for a given probability of frame loss. Also, it is presented that how the probability and the required size are effected by the number of multiplexed FR connections and FR transmission links.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.5A
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• pp.863-872
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• 2001

본 논문에서는 PNNI(Private Network to Network Interface) 기반의 무선 ATM 망에서 이웃(neighborhood)과 이동 단말기의 위치 관계를 고려하여 계층화된 위치 등록기에 의한 적응적 위치 관리 기법을 제시한다. 제안된 위치 추적 과정에서는 단말기의 위치 영역을 홈(home) 이웃과 외부(foreign) 이웃으로 구분하고, 홈 이웃에서는 최하위 레벨의 위치 등록기와 홈 위치 등록기에 단말기의 위치를 등록하고 외부 이웃에서는 각 계층의 위치 등록기에 위치를 등록한다. 착신 단말기, 발신 단말기와 착신측 홈 이웃의 위치 관계를 고려하여 최소한의 비용으로 위치 파악 및 호 설정 과정을 수행한다. 그리고, PNNI 기반의 무선 ATM 망에서 제안된 적응적 위치 관리 기법을 기존 LR(Location Registers) 기법과 위치 관리비용 측면에서 성능을 비교하여 우수한 성능을 가지는 것을 알 수 있다.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.99-102
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• 1998

As multimedia communication services have been widely spreading, the amount of video traffic is rapidly increasing in B-ISDN environment based on the ATM technology. The image quality of MPEG services is very sensitive to the cell losses in ATM network, since each cell contains information needed at decoding process. Since the number of cells in each frame of MPEG is variable, this video smoothing technology need to prepare a buffer for no overflow or underflow at the transmission, requires that some number of cells be taken to the buffer in client before the playback of video. To ensure the high quality image of video, the video smoothing is scheduled by a Group of Picture unit. In this paper, we then apply the theory to reds nightmare encoded in MPEG, and find minimum smoothing buffer size, initial buffer size. It can be used to study the smoothing of stored video.

• Korean Management Science Review
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• v.11 no.2
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• pp.147-159
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• 1994

The problems of determining appropriate QOS(Quality of service) requirements of B-ISDN services and finding the corresponding NP(Network Performance) values satisfying the given QOS requirements are very important problems which are directly related to the successful operation of the ATM network, but have not been studied with enough attention yet. The QOS(NP) parameter definition, QOS measurements, and QOS managements are three major problems that should be solved. In this paper, we first introduce the basic concepts of QOS and NP and their relationships. Then we discuss more comprehensive concepts of QOS based on the layered structure of ATM services and the reference time, which can provide a systematic approach for QOS and NP mapping problems. We also provide examples of determining basic QOS(NP) parameters in the ATM layer and a specific example of QOS mapping based on the file transfer in ATM. The results of this paper can be used to establish the comprehensive QOS management model.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11S
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• pp.3260-3268
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• 1999

As the proliferation of multimedia traffic over High-speed Internet increases, ATM network will be vital to adopt as backbone network over various parts of Internet. In this paper, we investigate the performance of TCP/IP traffic flow over ABR and UBR of ATM service to study for the high throughput and good fairness by simulation technique. Although TCP is run in the transport layer, it is controlled by several methods, e.g, EPD, PPD, RED, EFCI, ER etc, in ATM layer when TCP uses the ABR/UBR service. Therefore, if one cell is discarded in ATM layer, a packet of TCp will be laost. And, also, along with the increasing of the number of VC among switches, the throughput and fairness will be degraded. In order to improve these degradations, we propose the effective parameter control operations of EFCI and ER on ABR service, and also suggest the buffer management methods on UBR service. Finally, through the simulation results, the improved throughput and fairness are shown.

• Convergence Security Journal
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• v.7 no.1
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• pp.99-106
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• 2007

We propose a distributed anchor Crossover Switches (CX) searching algorithm to play an important role in ensuring fast and seamless handoff control in wireless ATM networks. Within networks that are grouped together, connection management is done for each group by anchor switches, and Permanent Virtual Circuit (PVC) with a narrow bandwidth is assigned between anchors for exchange of information. The proposed algorithm enables quick searching of a targeted CX, makes management of the overall network easier, and reduces system overhead or propagation delay time, thus providing fast and seamless handoff.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.1
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• pp.1-8
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• 1997

A wide class of networking application services, such as video teleconferencing, VOD, LAN bridging, and distributed data processing require multipoint communications. The essential component inteh network to achieve this is a multicast packet switch which is capable of packet replication and switching. In this paper, we propose an efficient mukticast addressing scheme using the smallest number of routing bits which is deterministic lower bound. The new scheme performs all point-to-multipoint connection in radix-2 tree ATM switch like banyan network. Also, we provide a simple radix-2 switch block diagram for achieving our algorithm. And we investigate several addressing schemes for implementing multicasting in radix-r tree ATM switch and evaluate several performance factors, such as complexity of the additional header bits, requirement of the internal speedup and complexity of the major hardware.