• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.2 s.302
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• pp.11-20
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• 2005

In previous video conference system, when the number of participants in video conference increases by n, the bandwidth and memory of n2 is required. And also, it brings about increase in traffic and problem of a say during a conference in aspect of transmission of voice data. In this paper, we propose an algorithm of remote video conference using silence detection algerian to resolve the questions such as buffering method of video data in server and heavy traffic detection algorithm to the increase in participants. Video data buffering algorithm is not a method of broadcasting to other client in the server, but this algorithm uses two other methods; the buffering method of receiving compressed video data from clients and the indexing method for acquiring the video data of other participants in clients according to clients' bandwidth and network transmission speed. We apply a voice transmission algerian and a channel management algorithm to the remote video conference system. The method used in the voice transmission algorithm is a silence detection algorithm which does not send silent participants' voice data to the server. The channel management algorithm is a method allocating a say to the participants who have priority. In consideration of average 20 frames and 30ms regardless of a number of participants, we can safely conclude that the transmission of video and voice data is stable.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.298-300
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• 2005

Satellite payload on-board date compression unit are use for saving date storage space and reducing time to transmit payload data to the ground station. The KOMPSAT-3 payload will generate higher data rate than KOMPSAT-2 due to its better ground sample distance capacity. High input data rate and limited output transmission data rate might lead excessive compression and degraded image quality. This paper presents a trade-off study about data storage capacity and compression parameters for estimated KOMPSAT-3 system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.7
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• pp.728-736
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• 2014

Due to the recent development of mobile wireless telecommunication, RRHs(Remote Radio Heads) are widely being utilized to expand the cell coverage. Wire-link, an existing connection between DU(Digital Unit) and RRH through fiber cables, is considered to have limitations in relation to cost for a wide range of applications. This paper focuses on replacing the wire-link by wireless transmission using millimeter-wave, and implementing cellular network system through RRH from a remote location. After an influence element analysis on millimeter-wave wireless link transmissions, a comparative analysis between wireless link and an existing fiber link method will be made by utilizing currently commercialized LTE(Long Term Evolution), to prove the compatibility of millimeter-wave wireless link RRH method in replacing fiber link method without a significant decline in data transmission performance.

• Journal of Satellite, Information and Communications
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• v.8 no.2
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• pp.12-16
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• 2013

In this paper, we proceeded a study about the mobile software applications using smartphone technology. Firstly, we proposed a communication which a position data transmission technique using LED flashlight with built-in smartphone and we develop the application to perform a remote controller for beam-forming communication based on visible light associated with the position of Smartphone user. OOK modulation was applied for transmitting location data via LED backlight flash of smartphone and PD is used for detecting receiving light. In case of remote controller application which was controlled by WiFi IP-networking and it controls LED direction for beam-forming communication. These suggestion can be a good example for ubiquitous position recognition system using smart phone and software.

• Journal of the Korean Solar Energy Society
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• v.31 no.6
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• pp.72-77
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• 2011

The purpose for installation of offshore weather station is a measurement of wind resources and so on. If weather station is operated, it will be possible to analysis for wind resource and arrangement of wind farm by using measured data. In this paper, we carried out the development of offshore wind resource measurement system for measuring offshore wind resource. Also, In order to monitor for real-time wind data with 1 Hz, we installed the wireless transmission system. All wind characteristic data are sent to the server PC through the this system is connected outport of DataLogger. Transmitted wind data were used in order to look at in the Web-page and tablet PC on a real time basis in a graph. In this paper, we will introduce about the wind resource measurement and remote monitoring system that is the result of study.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.813-818
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• 2020

Recently, with the rapid increase in technology and users of smart devices, the smart watch market has grown, and its utility and usability are continuously expanding. The strengths of smartwatches are wearable portability, application immediacy, data diversity and real-time capability. Despite these strengths, smartwatches have limitations such as battery limitations, display and user interface size limitations, and memory limitations. In addition, there is a need to supplement developers and standard devices, operating system standard models, and killer application modules. In particular, monitoring and application of user's biometric information is becoming a major service for smart watches. The biometric information of such a smart watch generates a large amount of data in real time. In order to advance the biometric information service, stable peer-to-peer transmission of sensing data to a remote smartphone or local server storage must be performed. We propose a synchronization method to ensure wireless remote peer-to-peer transmission stability in a smart watch system. We design a wireless peer-to-peer transmission process based on this synchronization method, analyze asynchronous transmission process and proposed synchronous transmission process, and propose a transmission efficiency method according to an increase in transmission amount.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.216-219
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• 2008

It is necessary to study encryption for protection and safe transmission of the important information. Specially, the security in satellite data is also getting more and more important. This paper introduces DES and TDES algorithm, studies how to apply to satellite data with those algorithms and process of encryption and decryption for satellite data. Proposed encryption process in this paper will be utilized in satellite data for encryption in many satellites.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.486-488
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• 2004

The SRI (Super Resolution Imager) uses the CCD (Charge coupled device) detector that is used to convert the light into electronic data. The purpose of the SRI is to obtain data for high resolution images by converting incoming light into digital stream of pixel data. The SRI has a high resolution, so this electronic system needs more fast imaging data processing, detector control and data transmission systems. This report describes the required system specification and manufactured electronic system for satellite.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.280-282
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• 2003

The downlink data rates of the space-born payloads such as high-resolution optical cameras, synthetic aperture radars (SAR) and hyper-spectral sensors are being rapidly increased. For example, the image transmission rates of KOMPSAT-2 MSC(Multi-Spectral Camera) is 320Mbps even if on-board image compression scheme is used.[1] In the near future, the data rates are expected to be a level 500${\sim}$600Mbps because the required resolution will be higher and the swath width will be increased. This paper describes many techniques they enable 500Mbps data receiving and archiving system.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.811-813
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• 2003

The Satellite Technology Research Centre (SaTReC), Korea Advanced Institute of Science and Technology (KAIST) has developed and is to launch STSAT-1 (Science and Technology Satellite - 1) on 27$^{th}$ September 2003. The data collection system (DCS) is the one of its payloads. The DCS is a data relay system used for transmission from ground-based sensors through satellite to receiving station. This is one of the important methods collecting global data from the remote locations. In this paper, the DCS on the STSAT-1 will be introduced and the development of the mobile terminal (MT) will be reported.