In this paper, the hybrid-type current controller for inverter TIG systems was implemented and it was shown that the low-current pulse wave forms with high dynamic performance could be obtained. It is not sri easy to obtain the optimum gain tuning of PID controllers in digital PWM control methods. Hybrid control methods which uses automatic tuning techniques after adding fuzzy control methods to traditional PID controllers are chosen to improve the dynamic performance of PID controller's. To demonstrate the practical significance and dynamic performance improvement of the results, some simulation and experimental results are presented.

In this paper we propose a new conceptual system for a network clock in which all node clocks are simultaneously synchronized to the national standard by intermediation parameter of satellite time. Experiments have shown the possibility of its adoption by real networks. The new proposed method has various structural benefits, in particular all node clocks can be kept at the same hierarchical quality in contrast to the existing method. The measurement results show that the accuracy of the experimental slave clock system can be kept within a few parts In 1012 and the MTIE (Maximum Time Interval Error) sufficiently meets ITU-T G.811 for the primary reference clock. A prototype system with fully automatic operational functions has been realized at present and is expected to be directly used for communication network synchronization in the near future.

As using of network Increases rapidly, performance of system has been deteriorating because of the overhead and bottleneck. Nowadays, high speed I/O network standard, that is a sort of InfiniBand, PCI Express and so on, has come out to improve the limites of traditional I/O bus. The InfiniBand provides some protocols to service the applications such as SDP, SRP and IPoIB. In our paper, We explain the architecture of SDP(Socket Direct Protocol) and its features in channel based I/O network. And so, we provide a result of performance evaluation of SDP which is compared with current network protocol. Our experimental results also show that SDP is better than TCP/IP protocol.

This paper represents analysis on domestic technical regulation of high speed power line communications(PLC). Also it gives comparison of regulations for several countries which include U.S., Europe, and Japan. Power line communications radiates harmful interference in below 30MHz. This may intervene other radio equipments. The technical regulation must protect interference and provide clean radio environment. Finally this paper gives the proposal which is drafted by field tests for introducing high speed PLC.

This paper describes a development of smart power outlet and controller installation which is equipped for discrete power load environment such as office and home appliance. This system will sense a real-time power consumption and analyze the status, then, will keep optimal power use condition. The proposed method is applied to the real design, and that experimental results showed good performances on the wall-outlet, also, is expected to be used in the smart home automation installations.

This paper describes a new approach to Internet host mobility. We argue that local mobility, the performance of existing mobile host protocol can be significantly improved. It proposes Fast Moving Detection schemethat based on neighbor AP channel information and moving detection table. And, it composes Local Area Clustering Path (LACP) domain that collected in AP's channel information and MN interface information. It stored the roaming table to include channel information and moving detection. Those which use the proposal scheme will need to put LACP information into the beacon or probe frame. Each AP uses scheme to inform available channel information to MN. From the simulation result, we show that the proposed scheme is advantageous over the legacy schemes in terms of theburst blocking probability and the link utilization.

A광섬유 용융인장방법에 의해서 100GHz 채널간격을 갖는 DWDM용 8채널 광다중화기를 제작하였다. 8채널 광다중화기는 전광섬유형 Mach Zehnder 간섭계(MZI)를 3단으로 다단 연결하여 제작되었으며, 광다중화기 채널별 출력파장의 삽입손실을 균일하게 하기 위하여 파장에 대한 삽입손실변화가 적은 파장무의존형 커플러(WFC)를 이용하여 전광섬유형 MZI를 제작하였다. 광다중화기를 구성하는 광섬유형 MZI를 제작함에 있어서 경로차에 따른 출력 파장간격의 변화를 시뮬레이션을 통하여 알아보았고 다단연결에 의한 광다중화기 구현방법을 논의하였다. 전용 제작 장치를 이용하여, 전광섬유형 MZI를 제작하였으며, 미세한 파장을 저절하기 위해서, $CO_2$ 레이저를 이용하였다. 제작된 8채널 광다중화기는 평균 삽입 손실 2.1dB, 5.5dB에서의 통과대역폭이 0.8nm 이며, 25dB의 채널 Crosstalk를 갖는 특성을 얻을 수 있었고, 편광의존손실은 0.06dB 였다.

Transorthogonal 코드를 블록 단위로 확장해서 얻은 코드 집합을 적절하게 부집합으로 나누고 부호화기의 코드집합으로 할당한다. 이러한 부초화기를 병렬로 구성하고 정보 비트에 의해 선택된 부호화기의 각 출력 코드들을 합산하여 전송하는 다중코드 transorthogonal 변조 방식이 제안되어 있다. 본 논문에서는 다중코드 transorthogonal 변조 시스템의 부호화기로부터의 각 출력 코드를 또 다른 정보 비트로 이진 위상 변조한 후 합산하여 전송하는 시스템을 제안한다. 다중코드 transorthogonal 변조 시스템에서 적용된 정 진폭 부호화 알고리즘과정 전폭 부호화에 사용된 잉여비트를 이용한 수신 에러 정정 알고리즘을 제안된 시스템에 수정 없이 적용할 수 있으며 다중코드 transorthogonal 변조 방식에 비해 대역폭 효율이 개선됨을 보인다.

This Paper is implementing IPMP system based on Server/client Structured Linux. We referenced OpenIPMP System, which is a reference software of IPMP (Intellectual Property Management and Protection) solution. Using this system, we developed multimedia contents service providing system using MPEG-21's REL(XML), which is applicable to new media service environment.

In this paper, we describe ubiquitous environments and the trend of convergence that is an evolution path of. current telecommunication, and show the concept of broadband convergence network, service feature and evolution path. In order to converge wire and wireless communication, telecommunication and broadcasting, voice and data efficiently, broadband convergence network divides a network into service layer, control layer, transport layer, ubiquitous access and terminal layer. Broadband convergence network will be a network that can provide and control broadband multimedia services with QoS and security of different and customized level. Then we depict characteristics and types of broadband multimedia service, and describe the characteristic of broadband convergence network. Finally, we show ubiquitous network based on the broadband convert- gence network to provide ubiquitous service which is a future telecommunication service. We also describe requirements of ubiquitous network such as an intelligent and context based platform, convergence terminals, ubi- quitous computing devices, etc.