• Title/Summary/Keyword: port and channel

Search Result 305, Processing Time 0.027 seconds

Performance Analysis of Channel Multiple Access Technique for the Multimedia Services via OBP Satellite (OBP(On-Board Processing)위성의 멀티미디어 서비스를 위한 채널 다중접속 방식의 성능 분석)

  • 김덕년;이정렬
    • Journal of the Institute of Convergence Signal Processing
    • /
    • v.2 no.2
    • /
    • pp.83-88
    • /
    • 2001
  • In this paper, System performance parameters such as throughput, blocking probability and delay have been analyzed and expressed as a function of demanding traffic and service terminating probability, and we centers our discussion at particular downlink port of satellite switch which is capable of switching the individual spot beam and processing the information signals in the packet satellite communications with demand assigned multiple access technique. Delay versa throughput as a function of traffic parameters with several service terminating probability can be derived via mathematical formulation and simulation and the relative change of transmission delay was compared.

  • PDF

Performances of the Directional Control Solenoid Valve for a Combined Power Plant

  • Kim, Chul-Jin;Yun, Yu-Seong;Kim, Do-Tae;Lee, Il-Young
    • International Journal of Safety
    • /
    • v.11 no.2
    • /
    • pp.10-14
    • /
    • 2012
  • Recently, the combined power plants are refocused rapidly as a replaceable energy system of the nuclear power plant. The large turbine is revolved highly at 1800~3600 rpm. Thus, the turbine speed should be monitored with mechanical and electrical method for a safety. The electrical cutoff valve which blocks the flow channel with the electrical signal is with a built in. The aim of this study is to develop a manufacturing technology through by the localization of a solenoid actuated directional control valve. Especially the results show performances of the solenoid valve by the experiments and modeling and the reliability estimation. Applied load port pressure was changed rapidly on the form of a quadratic curve over time. And in the cases of square waveform when 0~100 V and 20~120 V input voltage, it was driven on a stable state until 13.4 Hz and 16.6 Hz, respectively. We think that this study will give useful data for the electricity safety system of the combined power plant gas turbine.

Development of remote monitoring system based on wire and wireless internet Environment (유.무선 인터넷 환경에 연동한 원격 감시시스템 개발)

  • 박상국
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2004.05b
    • /
    • pp.557-560
    • /
    • 2004
  • In this paper, wireless internet services are combined with conventional wire internet service system. These system support that instrument manager can be access his instrument by use personal mobile devices and instrument manager can be take emergency action by use mobile devices. for this, error signal of local instruments are transmitted to the serial port of local server through Rf wireless communication channel. Also, The image of local instruments are transmitted to the web monitoring screen of main server. Network Camera System Supports remote monitoring functions. The interfacing of nam server with external user are possible through the mobile devices.

  • PDF

Tidal asymmetry in the Keum River Estuary (금강하구의 비선형조석)

  • 최병호
    • Water for future
    • /
    • v.21 no.1
    • /
    • pp.87-94
    • /
    • 1988
  • Tidal asymmetry in the Keum River Estuary has been investigated from the observed tides. Despite strong frictional attenuation within the estuary, the $M_4$ tides reach significant amplitude, resulting in strong tidal distortion. The observed asymmetry over the area shows that generally more intense flood flows transport more sediment that do less intense ebb flows of longer duration. This causes filling of the estaury as evidenced by sand flats spreaded over the inner area. The spatial distribution of peak bottom stress associated with the dominant $M_2$ and $M_4$ tides calculated via two-dimensional numerical tidal model suggest that present tidal sedimentation regimemay be altered, sepecially in the approach channel to outer Kunsan Port and downstream part of the dike, due to the construction of barrier.

  • PDF

Spatial Structure of Hinterlands and Forelands of Pusan Container Export Port: the Cases of 3 National Flag Carriers (부산 컨테이너 수출항의 배후지와 지향지의 공간구조)

  • Cho, Su-Kyung
    • Journal of the Korean Geographical Society
    • /
    • v.28 no.3
    • /
    • pp.247-267
    • /
    • 1993
  • According to developing international economy since the World War II, the increase and competition of the national business is so empha-sized tht both the interest and the necessity about marine transportation playing the impor-thant role of international transportation are increased. Today, the container transportation, as called the innovation of marine transport has been prevailed since the 1970's. The purpose of this paper is to grasp the spatial structure of the hinterlands and forelands, its object is export container cargo at Pusan Export Port, as known for the transportation node of modern containerlization. In this study, for the purpose of grasping the relation between hinterlands and forelands of Korean export container cargo, first, I researched the transition of carloading about container cargo, the bistribution channel of cargo, the change of the items of container and the carlo-adings about transport route, secondly, I used the cluster analysis so as to group hinterlands according to the items of goods and forelands. The object of the analysis is container cargo of Choyang Line, Hanjin Shipping and Hyundai Merchant Marine of National Frag Carriers. The source materials used in this study are Trucking Data of Hanjin Co., Container Ren-tal Data of Samik Transport Co. and Transpor-ting Present Condition Tables of Hyundai Mer-chant Marine. 1. There are two kinds of the transport classi-fied by its form: FCL and LCL. In Pusan Con-tainer Export, a lot of textile goods, clothings and furniture, compound, electric goods, and so on are dealed with but the rate of occupation of the transport is getting lower while that of occupation of equipment, papers and agricultu-ral, mineral and livestock industry higher. 2. In 1990, the transports of container cargo in Korea consist of 7 services and round-the world lines. We can list North America lines, East-South Asian lines, Japan lines and Inter European lines, in order of the quantity of tran-sport form the largest to the smaller. We can have another list that Japan lines, North Ame-rica lines and East-South lines in order of the rate participation of national flag carriers, be-cacuse Korean foreign trade lay disproportionate emphasis on East-South Asian lines. Japan lines among them is the biggest import-export market. Since the rationlization policy of marine tran-sport in 1984, each of national flag carriers have its own lines. Hanjin Shipping predominates over North America lines, Choyang Line over New Zealand, Inter European and Austria lines and Hyundai Merchant Marine over Center-South America lines, in terms of the volume of transport. And small-to-medium sized shippers are prevailing in lines which are adjacent to Korea, Such as Japan lines and East-South Asian lines. 3. In relation to hinterlands and forelands of Choyang Line, the light industry goods, electric goods and machinary produced in Seoul and Pusan are exported to the major ports in Europe and Japan, the same produces in Suwon, Ulsan, Kumi are exported to European Ports, and those in Incheon and Kwangju Austrian and Japanese ports, and those in the rest regions to the major port in Japan. 4. In relation to hinterlands and forelands of Hanjin Shipping, the light industry goods pro-ducing in Seoul and Pusan, the electric goods and machinary in Incheon and Pyeongteck, are exported to New York and Los Angeles. Electric goods and machinary Masan, Anyang, Cheona, Cheongju and Incheon, Electric goods machinary and light industry goods in Kwangju and non mental goods in Pohang, are exported New York, Los Angeles and Oakland. 5. In relation to hinterlands and forelands of Hyundai Merchant Marine, the region of Seoul, Pusan and Incheon closely related with the main ports in U.S.A. The rest regions with Montreal. The hinterlands of export container cargo can be classified by its export items into three kinds: the large city, industrial city and the rest city. Choyang Line's forelands are European lines, Japan lines and Austria lines, and Hanjin Shipping's forelands are North America lines, and Hyundai Merchant Marine's forelands are North America lines and Japan line. 3 National flag carriers' major forelands are determined by the size of port and the shipper's convenient use of the port terminal.

  • PDF

A Study on the Necessity of the Resurrection of Administration Organization for the Realization of Super Nation of Maritime and Fishery (해양강국 실천을 위한 행정조직 부활의 필요성 연구)

  • Kim, Hong-Seop
    • Journal of Korea Port Economic Association
    • /
    • v.27 no.4
    • /
    • pp.313-346
    • /
    • 2011
  • The Roman thinker, Cicero said, "The Nations that rule the sea, rule the world". In the world history, the countries done critical roles, have emphasized the importance of the sea. The world history is called as the histories of the countries which governed the sea, such as Phoenicia, Greece, Carthago, Roma, Portugal, Spain, England, and USA. The sea is not only the political, economical, social and cultural basis, serving as the origin of resources and channel of communication, logistics and distribution but also the area of dreams and imaginations and ground of potentiality and visions. This paper reviewed the major countries and their histories to realize the vision of Korea, super power country of maritime and fishery. Main maritime policies and its core issues and prospects of Korea were reviewed. And on the basis of these reviews, the vision of super power country of maritime and fishery was suggested. The vision, the 5th super power country of maritime and fishery in 2020, and 10th country of maritime technology level in 2020 and their details were proposed also. For achieving the vision, the resurrection of MOMAF is necessary and its reasons and 5 necessities were suggested. And the directions of the resurrection of MOMAF were proposed in terms of two viewpoints, policy/functional and institutional basis. I think Korea, the super power country of maritime and fishery, can be realized only when MOMAF may be resurrected.

Measurement of Reference Phase Offset for the Loran-C Transmitting Signal of Pohang (포항 로란-C 송신 신호의 기준위상 오프셋 측정)

  • Lee, Chang-Bok;Won, Sung-Ho;Lee, Jong-Koo;Kim, Young-Jae;Lee, Sang-Jeong;Yang, Sung-Hoon
    • Journal of Navigation and Port Research
    • /
    • v.36 no.6
    • /
    • pp.475-480
    • /
    • 2012
  • In order to establish eLoran (enhanced Long Range Navigation) system, it needs the advancement of receiver, transmitter, data channel addition for Loran information, differential Loran sites for compensating Loran-c signal and ASFs (Additional Secondary Factors) database, etc. In addition, the precise synchronization of transmitting station to the UTC (Coordinated Universal Time) is essential if Loran delivers the high absolute accuracy of navigation demanded for maritime harbor entrance. For better timing synchronization to the UTC among transmitting stations, it is necessary to measure and monitor the transmission delay of the station, and the correction information of the transmitting station should be provided to the user's receivers. In this paper we presented the measurement method of absolute delay of Pohang Loran transmitting station and developed a time delay measurement system and a phase monitoring system for Loran station. We achieved -2.23 us as a result of the absolute phase delay of Pohang station and the drift of Loran pulse of the station was measured about 0.3 us for a month period. Therefore it is necessary to measure the delay offset of transmitting station and to compensate the drift of the Loran signal for the high accuracy application of PNT (Positioning, Navigation and Timing).

Development and verification of a combined method of BEM and VOF (BEM과 VOF법을 결합한 수치모델의 개발과 그 타당성 검토)

  • Kim Sang-Ho;Yamashiro Masaru;Yoshida Akinori;Hashimoto Noriaki;Lee Joong-Woo
    • Journal of Navigation and Port Research
    • /
    • v.29 no.10 s.106
    • /
    • pp.853-858
    • /
    • 2005
  • Recently, various novel numerical models based on Navier-Stokes equation have been developed for calculating wave motions in the sea with coastal or ocean structures. Among those models, Volume Of Fluid (VOF) method might be the most popular one, and it has been used for numerical simulations of wave motions including complicated phenomena of wave breakings. VOF method, however, needs enormous computation time and large computational storage memories in general, thus it is practically difficult to use this method for calculations in the case of random waves because long and stable computation (e.g for more than 100 significant wave periods) is required to obtain statistically meaningful results. On the other hand if the wave motion is potential motion, Boundary Element Method (BEM), which is a much faster and more accurate method than VOF method, can be effectively used. The aim of this study is to develop a new efficient model applicable to calculations of wave motion and/or wave-structure interactions under random waves. To achieve this, a strictly combined BEM-VOF model has been developed by making the best use of both methods' merits; VOF method is used in a restricted fluid domain around a structure where complicated phenomena of wave breakings may exist, and BEM is used in the other domains far from the disturbance where the wave motion may be assumed to be potential. The verification of the model was performed with numerical results for Stokes' 5th order wave propagation and a random wave propagation.

Development of a 4S Multiple Media Switching Server and an Information Exchange System (4S 다중매체 스위칭 서버와 육해상 정보교환 시스템 개발)

  • Mun, Seong-Mi;Jang, Won-Seok;Son, Joo Yong;Yang, Gyu-Sik
    • Journal of Navigation and Port Research
    • /
    • v.37 no.3
    • /
    • pp.275-281
    • /
    • 2013
  • Ship Standard Network was submitted as a common subject of e-navigation by 81th IMO MSC 2005. This agenda was given an official status with strategy planning of e-navigation for Ship Standard Network after approval of WG program of 81th MSC 2006. Nowadays approximately 400 heterogeneous navigation and communication equipments are working on ships at sea. Standardization of ship network is to support exchanging various data efficiently. Among them, 4S network is defined as a wireless communication network between ship to ship and ship to shore which provides unceasing communication channel ship to shore. It has been expected to trigger various services and applications based on 4S network. However, no technologies and products has been appeared at fields yet. but now there's not specific technologies and developing products. In this paper, We developed a 4S multiple media switching server and a ship-land information exchange system to overcome the heterogeneity and provide efficient communication environments.. The performance of the implemented system was verified by TTA(Telecommunications Technology Association) V&V(Verification and Validation).

A Time Comparison Measurement Technique for eLoran Receivers (시각비교를 위한 eLoran 수신기 지연측정 기술)

  • Lee, Chang-Bok;Lee, Jong-Koo;Lee, Young-Kyu;Hwang, Sang-wook;Yang, Sung-Hoon
    • Journal of Navigation and Port Research
    • /
    • v.40 no.6
    • /
    • pp.385-390
    • /
    • 2016
  • ELoran Systems can provide Position, Navigation, and Time services with comparable performance to Global Positioning Systems (GPS) as a back up or alternative system. High timing and navigation performance can be achieved by eLoran signals because eLoran receivers use "all-in-view" reception. This incorporates Time of Arrival (TOA) signals from all stations in the service range because each eLoran station is synchronized to Coordinated Universal Time (UTC). Transmission station information and the differential Loran correction data are transmitted via an additional Loran Data Channel (LDC) on the transmitted eLoran signal such that eLoran provides improved Position Navigation and Timing (PNT) over legacy Loran. In this paper, we propose a technique for adapting the delay time compensation values in eLoran timing receivers to provide precise time comparison. For this purpose, we have designed a system that measures time delay from the crossing point of the third cycle extracted from the current transformer at the end point of the transmitter. The receiver delay was measured by connecting an active H-field, an E-field and a passive loop antenna to a commercial eLoran timing receiver. The common-view time transfer technique using the calibrated eLoran timing receiver improved the eLoran transfer time. A eLoran timing receiver calibrated by this method can be utilized in the field for precise time comparison as a GNSS backup.