• Title/Summary/Keyword: Communications

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Millimeter-wave Technologies for ITS Wireless Communications

  • Fujise, Masayuki
    • Information and Communications Magazine
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    • v.19 no.9
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    • pp.31-42
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    • 2002
  • CRL (Communications Research Laboratory, Independent Administrative Institution, Japan) is developing ITS wireless communication technologies in millimeter-wave frequency region. Technologies are categorized for inter-vehicle communications (IVC) and road-vehicle communications (RVC). In this paper, system concepts and the experimental facilities are introduced. The experimental facility for inter-vehicle communications is gotten ready in 60 GHz frequency region and the experimental system for road-vehicle communications is based on RoF (Radio on Fiber) technology in 36-37GHz frequency region.

Demonstration of Time- and Wavelength-Division Multiplexed Passive Optical Network Based on VCSEL Array

  • Mun, Sil-Gu;Lee, Eun-Gu;Lee, Jie Hyun;Park, Heuk;Kang, Sae-Kyoung;Lee, Han Hyub;Kim, Kwangok;Doo, Kyeong-Hwan;Lee, Hyunjae;Chung, Hwan Seok;Lee, Jong Hyun;Lee, Sangsoo;Lee, Jyung Chan
    • ETRI Journal
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    • v.38 no.1
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    • pp.9-17
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    • 2016
  • We demonstrate a time- and wavelength-division multiplexed passive optical network system employing a vertical-cavity surface-emitting laser array-based optical line terminal transceiver and a tunable bidirectional optical subassembly-based optical network terminal transceiver. A packet error-free operation is achieved after a 40 km single-mode fiber bidirectional transmission. We also discuss an arrayed waveguide grating, a photo detector array based on complementary metal-oxide-semiconductor photonics technologies, and low-cost key devices for deployment in access networks.

Development of the Test and Mnitor System for Satellite Communications Payload and Network

  • Kong, Nam-Soo
    • 제어로봇시스템학회:학술대회논문집
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    • 1994.10a
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    • pp.34-37
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    • 1994
  • A satellite communications monitoring and control system(SCMCS) has been developed at ETRI to provide the capabilities of in-orbit test (IOT) for communications payload and communications system monitoring(CSM) for the satellite communications services. The paper discusses the system level design of SCMCS and its tasks.

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IDNet: Beyond All-IP Network

  • Jung, Heeyoung;Lim, Wan-Seon;Hong, Jungha;Hur, Cinyoung;Lee, Joo-Chul;You, Taewan;Eun, Jeesook;Kwak, Byeongok;Kim, Jeonghwan;Jeon, Hae Sook;Kim, Tae Hwan;Chun, Woojik
    • ETRI Journal
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    • v.37 no.5
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    • pp.833-844
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    • 2015
  • Recently, new network systems have begun to emerge (for instance, 5G, IoT, and ICN) that require capabilities beyond that provided by existing IP networking. To fulfill the requirements, some new networking technologies are being proposed. The promising approach of the new networking technology is to try to overcome the architectural limitations of IP networking by adopting an identifier (ID)-based networking concept in which communication objects are identified independently from a specific location and mechanism. However, we note that existing ID-based networking proposals only partially meet the requirements of emerging and future networks. This paper proposes a new ID-based networking architecture and mechanisms, named IDNet, to meet all of the requirements of emerging and future networks. IDNet is designed with four major functional blocks-routing, forwarding, mapping system, and application interface. For the proof of concept, we develop numeric models for IDNet and implement a prototype of IDNet.

Pre-select Diversity with the Aid of Downlink Beamforming in Indoor MC-CDMA System

  • Pham, Van-Su;Le, Minh-Tuan;Linh Mai;Yim, Mun-Hyuk;Yoon, Gi-Wan;Kim, Dong-Hyun
    • Journal of information and communication convergence engineering
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    • v.2 no.2
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    • pp.71-75
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    • 2004
  • In non-selective frequency environment, it is difficult to take the advantage of path diversity. In the literature, some methods have been proposed to solve the issue. This paper presents a new method to obtain the resolvable path in Indoor Multi-carrier Code Division Multiple Access (MC-CDMA) system by using downlink beam forming. With the aid of downlink beamforming, the most reliable path is found and chosen for the communication link. The new approach is evaluated in term of bit error rate (BER) and power consumption. The simulation results show that the new approach can get better BER performance. However, the cost of BER improvement is a small degradation in power reservation.

Context-aware Multimedia Framework based on Software Agent Platforms

  • Hendry;Seongjoon Pak;Yumi Sohn;Kim, Munchurl
    • Proceedings of the Korean Information Science Society Conference
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    • 2003.10b
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    • pp.253-255
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    • 2003
  • We address an integrated multimedia framework based on a software agent platform for context-aware multimedia computing. We adopt the FIPA (Foundation for Intelligent Physical Agents) platform which provides agent communications and management mechanisms. In order to express context information, we use MPEG-21 metadata for describing user characteristics and usage environment. We encapsulate such context information as a FIPA message to be delivered between agents. Based on context information, appropriate multimedia content delivery becomes possible. We present our system implementation with a use case scenario and show that our proposed framework is effective for context-aware multimedia computing so that personalization of multimedia consumption can be possible.

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Novel High-Rate High-Performance Space-Time Codes

  • Le, Minh-Tuan;Linh Mai;Pham, Van-Su;Yoon, Gi-Wan
    • Journal of information and communication convergence engineering
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    • v.2 no.2
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    • pp.67-70
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    • 2004
  • In this paper, we propose two novel high-rate high-performance space-time codes for multiple-input multiple-output (MIMO) systems. When $n_T$ transmit antennas and When $n_R$ = When $n_T$ receive antennas are deployed, the two proposed codes respectively offer transmission rates of (When $n_T$ -1) and (When $n_T$ -2) symbols per channel use and diversity orders of 3 and 5. As a consequence, our proposed codes allow the MIMO systems to employ a simple detection technique based on QR decomposition. Moreover, for equal or even higher spectral efficiencies, our proposed codes always provide much better bit error rate (BER) performances than V-BLAST architecture does when When $n_R$ = When $n_T$. Computer simulation is given to verify performances of our proposed codes.

Blind Source Separation of Instantaneous Mixture of Delayed Sources Using High-Order Taylor Approximation

  • Zhao, Wei;Yuan, Zhigang;Shen, Yuehong;Cao, Yufan;Wei, Yimin;Xu, Pengcheng;Jian, Wei
    • ETRI Journal
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    • v.37 no.4
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    • pp.727-735
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    • 2015
  • This paper deals with the problem of blind source separation (BSS), where observed signals are a mixture of delayed sources. In reference to a previous work, when the delay time is small such that the first-order Taylor approximation holds, delayed observations are transformed into an instantaneous mixture of original sources and their derivatives, for which an extended second-order blind identification (SOBI) approach is used to recover sources. Inspired by the results of this previous work, we propose to generalize its first-order Taylor approximation to suit higher-order approximations in the case of a large delay time based on a similar version of its extended SOBI. Compared to SOBI and its extended version for a first-order Taylor approximation, our method is more efficient in terms of separation quality when the delay time is large. Simulation results verify the performance of our approach under different time delays and signal-to-noise ratio conditions, respectively.

Development of ETRI satellite simulator-ARTSS

  • Kang, J.Y.;Lee, S.;Hong, K.Y.;Shin, K.K.;Rhee, S.W.;Choi, W.S.;Oh, H.S.;Kim, J.M.;Chung, S.J.
    • 제어로봇시스템학회:학술대회논문집
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    • 1994.10a
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    • pp.49-53
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    • 1994
  • Advanced Real-Time Satellite Simulator(ARTSS) has been developed to support the telemetry, tracking and command operations of the ETRI satellite control system and to provide satellite engineers a more powerful and informative satellite simulations tool on the desktop. To provide extensive simulation functions for a communication satellite system in the pre-operational and operational missions, ARTSS uses a geosynchronous orbit(GEO) satellite model consisting of the attitude and orbit control subsystem, the power subsystem, the thermal subsystem, the telemetry, command and ranging subsystem, and the communications payload subsystem. In this paper, the system features and functions are presented and the satellite subsystem models are explained in detail.

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Factors Influencing Brand Image and Purchase Intention in Indonesia's Furniture Distribution Channels

  • Felicia HERMAN;Ricardo INDRA;Kurniawati;Michael CHRISTIAWAN;Muhammad ARAS
    • Journal of Distribution Science
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    • v.22 no.7
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    • pp.33-42
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    • 2024
  • Purpose: The furniture industry has a huge potential for growth in Indonesia. Due to Indonesia's vast natural resources, furniture designers, makers, and retailers are given ease of access. The research analyzes the influence of service quality, promotion, product, and price on brand image and purchase intention in Indonesia's furniture distribution channels. Research design, data, and methodology: The variables used are service quality, promotion, product, price, brand image, and purchase intention. This research is cross-sectional research, which will be conducted among the furniture consumers in Indonesia, from the Instagram followers of a community as of 31 July 2023 with 837.5 thousand followers. The tools that will be used are surveys, conducted according to the sample size and processed using SMARTPLS 4 and the SEM-PLS model. Results: The findings urge that some variables have a significant influence on purchase intention directly but become less significant when influenced by brand image. Some variables can influence purchase intentions significantly through brand image, even if the certain variable did not have a significant influence on purchase intention directly. Conclusions: By knowing the significance of the variables towards brand image and purchase intention, ones with major influence can be implemented as a strategy to improve marketing in Indonesian furniture distributors.