• Title/Summary/Keyword: Navigation Channel

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Packet Performance Simulation of ACL/SCO Link in Bluetooth Piconet (블루투스 Piconet에서 ACL/SCO 링크의 패킷 성능 시뮬레이션)

  • Kim, Do-Gyun;Roh, Jae-Sung;Cho, Sung-Eon;Cho, Sung-Joon;Kim, Jung-Sun
    • Journal of Advanced Navigation Technology
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    • v.6 no.1
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    • pp.77-83
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    • 2002
  • The emergence of Bluetooth as a radio interface scheme has allowed electronic devices to be instantly interconnected as ad-hoc networks. These short range ad-hoc wireless networks are called piconets, operated in the unlicensed 2.45 GHz ISM(Industrial, Scientific, Medical) band where up to eight devices may be used to configure single or overlapping piconets. In this paper, we have simulated the PER(Packet Error Rate), the ratio of received packet and payload BER(Bit Error Rate) of piconet with packet types of Bluetooth ACL/SCO(Asynchronous Connection Less/Synchronous Connection Oriented) link over wireless ad-hoc environment. The Rayleigh fading effects are considered as channel model, and the simulation results are based on the baseband model of Bluetooth specification. From the simulation results, the PER and the throughput of Bluetooth piconet are sensibly affected by the packet type of ACL/SCO link.

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Reliability Improvement of the Industrial Equipment Control and Management System Using ZigBee Wireless Network Technology (ZigBee 무선 네트워크 기술을 이용한 산업용 장비 제어 및 관리 시스템의 신뢰성 향상)

  • Kim, Woo-Jin;Kang, Chul-Gyu;Oh, Chang-Heon
    • Journal of Advanced Navigation Technology
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    • v.13 no.5
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    • pp.742-748
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    • 2009
  • Zigbee wireless communication technology has features which are low cost, low power and coping ability against a high delay time when the automatic wireless system is manufactured. Therefore, in this paper, we research a method improving the data transmission reliability of the industrial equipment control and management system using zigbee wireless communication technology. we used a convolutional code with code rate R=1/2, constraint K=5 and generation polynomial constant g1=(10111) and g2=(10011) as a reliability method. From the transmission simulation at LOS environment, we are able to predict the transmission error performance according to the distance difference. Furthermore, At the PER performance analysis, we can get the result that this system reliability with convolutional code is improved about 5 times than the existing system. From these results, we can prove that the convolutional code is the solution to improve the system reliability of the industrial equipment control and management system using zigbee wireless communication technology.

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A Study on the Analysis of Danger Elements in Navigational Areas Adjacent Mokpo port (목포 인근해역 항행 위험요소에 관한 분석)

  • Park Jung Ho;Keum Jong Su;Noh Chang Keun;Yun Myung Oh;Sin Chul Ho;Jeong Jae Yong;Park Gyei Kark
    • Proceedings of KOSOMES biannual meeting
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    • 2003.11a
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    • pp.75-83
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    • 2003
  • The navigation area approach to Mokpo port consists of narrow channels with 30mile section, and the route is crossed with many fairways. Specially, except Mokpo-Gu fairway routeing is not assigned and there are many threatening factors against the safe operation of vessel because fishing and mining areas are designated Therefore, this paper proposed a plan for safe passage through a maritime transportation environmental assessment with the analysis of surrounding environment, danger element of navigation, traffic observation and marine accidents.

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A Predistortion Linearizer Using the In-phase Modulator (동 위상 변조기를 이용한 전치왜곡 선형화기)

  • Kim, Eel-Kou;Jeon, Ki-Kyung;Kim, Young;Youn, Young-Chul
    • Journal of Advanced Navigation Technology
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    • v.10 no.1
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    • pp.41-47
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    • 2006
  • In this paper, a predistortion linearizer using the in-phase modulator is proposed. The harmonic generator of the proposed predistorter extracts a second harmonic signals. These signals are divided in-phase and quadrature-phase signals, and then amplifying each signals using variable gain amplifier. An in-phase modulator, modulate fundamental signal with second harmonic signals, generates the predistortion intermodulation distortion (IM) signals and controls amplitude and phase of them with modulation factors. As a result, this predistorter is suppressed intermodulation distortion signals of power amplifier effectively. The proposed linearizer has been implemented to operate in Cellular-band. The test results show that the third order IM is cancelled more than 20dB in case of CW 2-tone signals with ${\Delta}f$=1MHz. Also, it's improved the adjacent channel power ratio (ACPR) more than 7dB for IS-95 CDMA 1FA signals.

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Compensation of Distorted WDM signals due to Cross Phase Modulation Effects using Mid-Span Spectral Inversion (상호 위상 변조에 의해 왜곡된 WDM 신호의 Mid-Span Spectral Inversion을 이용한 보상)

  • Lee, Seong-Real
    • Journal of Advanced Navigation Technology
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    • v.7 no.2
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    • pp.128-134
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    • 2003
  • In this paper, we investigated the degree of compensation for WDM channel signal distortion due to chromatic dispersion, self phase modulation (SPM) and cross phase modulation (XPM) as a function of transmission length using mid-span spectral inversion (MSSI) compensation method. The considered system is $3{\times}40$ Gbps intensity modulation direct detection (IM/DD) WDM transmission system. This system has highly nonlinear dispersion shifted fiber (HNL-DSF) as a nonlinear medium in optical phase conjugator (OPC). We confirmed that the transmission length is more increased by applying MSSI to distorted signal due to chromatic dispersion, SPM and XPM as dispersion coefficient of fiber becomes higher. And the compensation degree of distorted WDM channels due to chromatic dispersion, SPM and XPM becomes better stable as dispersion coefficient of fiber becomes higher.

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WLAN OFDMA Random Access Based Communications for In-Aircraft Wireless Sensor Networks (비행체 무선 센서망을 위한 무선랜 OFDMA 임의접근 기반 통신)

  • Ahn, Woojin;Kim, Ronny Yongho
    • Journal of Advanced Navigation Technology
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    • v.20 no.3
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    • pp.252-257
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    • 2016
  • In this paper a novel access scheme for uplink multiuser transmission based on IEEE 802.11ax random access in in-aircraft wireless sensor networks is proposed. The proposed scheme provides an efficient access control mechanism with three divisions of OFDMA backoff counter (OBO): access, deferring, dropping, which controls the number of potential uplink transmission stations. The proposed scheme can be used efficiently in in-aircraft wireless sensor network where a large number of sensors need to be supported. By using the proposed scheme, since in-aircraft sensors attempt channel access using the proposed differentiated OBO parameters, the number of stations exceeds the access capacity can be efficiently controlled. This paper also provides the mathematical analysis of the proposed scheme, regarding the optimal parameters. According to the performance analysis, the proposed scheme is able to efficiently control the access behavior of wireless sensors in the network.

The Analysis of Voice Communication Traffic based on ADS-B Providing the Aiming Altitude Parameter (목적고도 정보를 제공하는 ADS-B 환경의 음성통신량 분석)

  • Hyun, Jung-Wook;Gil, Hyun-Cheol;Ahn, Dong-Mhan;Hong, Gyo-Young
    • Journal of Advanced Navigation Technology
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    • v.15 no.6
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    • pp.946-952
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    • 2011
  • In term of inaccuracy of information and increasing channel occupancy time, the use of voice communication in Air Traffic Control has many problems. In order to improve it, ICAO proposed digital communication and ADS-B system that is more effective for voice communication in ATC. For improvement of effectiveness to add additional parameter to designated ADS-B In-Out data group, many studies being performed. In this paper, we analysis voice communication for reduce the communication traffic in ATC and simulate to add aiming altitude parameter for comparative effect analysis of communication traffic between pilot and controller. The result of the analysis were successfully validated that reduction of communication traffic in ADS-B environments.

The Activation of Shipping Logistics Information System on Logistics Performance (해운물류정보(海運物流情報)시스템의 활성화요인(活性化要因)이 물류성과(物流成果)에 미치는 영향(影響)에 관한 연구(硏究))

  • Kim, Seong-Kyu;Cho, Sung-Mou;Lee, Yong-Ho;An, Ki-Myung
    • Journal of the Korean Institute of Navigation
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    • v.25 no.2
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    • pp.159-172
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    • 2001
  • The information technology(IT) development of telecommunication, along with the information analyzation over the world, enables the firms to process their inner and outer operations through Electronic Data Interchange (EDI) system. And the concept of logistics has become more important to the enterprises in strategic sense because it had aggrandized itself to more comprehensive and integrative concept. Also the world shipping market is more competitive than any other market. In these environment, to maintain competitive power, shipping firms process operations by Logistics Information system(LIS), And then, reduce the working processes, working time and its costs. So the LIS has become more important in developing our national logistics system and industry. Therefore, this study purposes on empirically analyzing the activation factors of shipping LIS and the relationship these, factors with logistic performances in the shipping industry. Considering environments of Shipping logistics information system, this study sets up the research model and hypothesis to examine the activation factors of shipping LIS and the relationship these factors with logistic performances. We used the field data on the 163 numbers of firms(29 overseas shipping companies and 133 forwarding Agency) to get the empirical evidence. According to the study results, The shipping LIS activation factors which the sample firms recognized as important: were top managers support, well structured communication channel, strategic plans connection and inner information analyzation level. And IS organization & human resources, IS discipline & training, software development, IS organizational alignment, database management system, information standardization, competitive advantage, financial support and government support represent partially significant. Also, the current shipping LISs main problems are expensive system cost, standardization of working processs, institutions imperfection and systems interaction defect. So these problems must be improved to activate shipping LIS.

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Multipath Routing Protocol based on Multi-Rate Transmission in Mobile Ad Hoc Networks (이동 에드혹 네트워크에서 다중전송률전송에 기반한 다중경로 라우팅 기법)

  • Lee, Kang-Gun;Park, Hyung-Kun
    • Journal of Advanced Navigation Technology
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    • v.18 no.3
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    • pp.236-241
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    • 2014
  • In a mobile ad hoc networks, multi-hop transmission is used to transfer data from source node to destination node and the routing protocol is the one of the important technical issues. The links between nodes can be unstable due to the changes of node location and channel conditions, and it can induce link error. To solve this problem, multipath routing was proposed. Multipath routing can reduce the data congestion and increase data throughput. In the multipath routing, however, each path can be interfered by the other path, and it can aggravate network performance. In this paper, we propose the multipath routing technique in the multi-rate MANET. The proposed multipath routing can avoid interference without the knowledge of node location. Simulation results show that the proposed multipath routing can reduce transmission delay and error.

Sensitivity Analysis of Hydrodynamic Derivatives on Characteristics of Manoeuvring Motion of Manta-type Unmanned Undersea Test Vehicle (Manta형 무인잠수정의 조종운동 특성에 미치는 유체력미계수의 민감도 해석에 관한 연구)

  • Bae, Jun-Young;Sohn, Kyoung-Ho
    • Journal of Navigation and Port Research
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    • v.32 no.8
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    • pp.603-609
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    • 2008
  • Manta-type Unmanned Undersea Test Vehicle(MUUTV) is based on the same design concept as Unmanned Undersea Vehicle called Manta Test Vehicle(MTV), which was originally built and operated by the Naval Undersea Warfare Center(Lisiewicz et al., 2000, Sirmalis et al. 2001). The authors carried out the sensitivity analysis of the response of manoeuvring motion of MUUTV to changes in hydrodynamic derivatives, In order to calculate the sensitivity indices of hydrodynamic derivatives on MUUTV, the method by Sen(2000) was adopted Basically the dynamic mathematical model with six degrees of freedom by Feldman(1979) is used but a little revised, refered to Sohn et al.(2006) and some experiment in circulating water channel. Through the present research, some hydrodynamic derivatives of significance are found out, and also the numerical simulation using simplified mathematical model based on result of sensitivity analysis is ascertained to be enough for prediction of manoeuvring characteristics of MUUTV.