• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.4
• /
• pp.3-12
• /
• 2001

Bluetooth stands for a technical specification for radio communication or a radio equipment that uses the Bluetooth specification of which the main purpose is to substitute the complicated communication cable of the informative device or electronic apparatus used at home or industrial fields, and was expected to be a mastermind of revolution in the short range radio communication. But the Bluetooth has recently been led to the mobile communication field which is somewhat apart from the primary purpose of Bluetooth and occur the question on its effectiveness. This paper review the situation of Bluetooth in the aspect of radio technical criteria and propose the direction for improvement of regulatory basis considering the prospection of the technical development of Bluetooth.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.29 no.1
• /
• pp.17-22
• /
• 2016

The activation energy of a material is an important factor that significantly affects the lifetime and can be used to develop a degradation model. In this study, a thermal analysis was carried out to evaluate and collect quantitative data on the degradation of insulation materials like EPR and CSP used for nuclear power plant cables. The activation energy was determined from the relationship between log ${\beta}$ and 1/T based on the Flynn.Wall.Ozawa method, by a TGA test. The activation energy was also derived from the relationship between ln(t) and 1/T based on isothermal analysis, by an OIT test. The activation energy of EPR derived from thermal analysis was used to calculate the accelerated aging time corresponding to the number of years of use, employing the Arrhenius equation, and determine the elongation corresponding to the accelerated aging time.

• The Journal of the Korea Contents Association
• /
• v.3 no.2
• /
• pp.78-86
• /
• 2003

The Minisoy of Information and Communication(MIC) requires telecompanys to share base stations in order to prevent the duplicated investment and environmental destruction which would be caused by the indiscreet construction of basestations for enlarging their own service area among telecompanys. This paper discusses' the problems of mobile communication services that have been generated in common-repeater at the Metropolitan subway. These problem include factors of power obstacles, communication equipment and establishment obstacles. The content of this paper is helpful in organizing the basestation sharing of IMT-2000 and the 4th generation mobile system, and provides the basics of a higher quality service for common-service communication.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.5
• /
• pp.8-18
• /
• 2009

CableLAB published DOCSIS 3.0 Specifications to supply broadband access to homes and small businesses. The primary technique of DOCSIS 3.0 Specification is channel bonding which provides cable operators with a flexible way to significantly increase up/downstream speeds. In this paper, we propose the upstream scheduler that serves channel bonding. Proposed scheduler consists of two sub-scheduler: bonding group scheduler and channel scheduler. Also, we propose three scheduling algorithms to allocate request bandwidth of CM to each bonding channel: equivalent scheduling algorithm, current request-based scheduling algorithm, and last grant-based scheduling algorithm. In order to evaluate the performance of these algorithms and DOCSIS 3.0 MAC protocol, we develop the DOCSIS 3.0 simulator with the network simulator, OPNET, to model DOCSIS network, CMTS, and CM. Our results show that equivalent scheduling algorithm is superior to others in the view of transmission delay and throughput and DOCSIS 3.0 protocol provides higher throughput than pre-DOCSIS 3.0 protocol.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.03a
• /
• pp.768-773
• /
• 2009

Measuring method being applied for off-shore works is performed by using data logger or manual measuring instrument with wiring the cable connected from the sensor up to the position where measuring is allowed.(upper part of embankment or marine structure) Measuring management by using existing measuring method may be acceptable on the condition that the ground deformation volume(vertical, horizontal) is generally minimal and the site condition is good. But loss of measuring instrument, sensor cable failure or cutting is taken place frequently due to significant change of ground behavior caused by an external force change(embankment, excavation) under very soft ground condition(N value below 0-4). In case of the marine works, in particular, loss rate of measuring instrument is highly represented due to the factors of working barge anchoring, constructional interference and natural disaster. In order to solve these problems, measuring management was performed with employing underground wireless system at the immersed tunnel site. Measuring data was obtained freely under the marine environment by using underground wireless communication and cable cutting potential by ground behavior could be reduced. Measuring cost savings and its installation convenience were maximized by way of off-shore tower installation or cabling and by minimizing constructional interference of off-shore working barge. This case of measuring management was accomplished successfully.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2002.05a
• /
• pp.205-208
• /
• 2002

When establishing the submarine optical fiber table between international and domestic, marine survey in advance it grasps the submarine geological features which is accurate and a depth of water condition. And the route which is safe for selecting and submarine optical fiber cable laying it is a work which secures an ease one location. If also, the PLGR the submarine of optical fiber table root the sea contamination material (rope, wire and net) it removes in advance and if the submarine of the optical fiber cable ease it does to arrive safely. And it is a work the Plough and ROV laying work hour laying work efficiency improvement and laying equipment it will be able to protect. So, This paper presents the monitoring system of ship information management and operation for marine survey and PLGR work in submarine optical fiber table construction enterprise. In order to achieve these purpose, overall serial multi-port communication modulo of configuration, realtime processing for management and operation of receiving data, realtime graph and a printout are described.

• Journal of Digital Convergence
• /
• v.13 no.9
• /
• pp.219-224
• /
• 2015

The broadcasting communications service will accelerate its development with the convergence of broadcasting media and internet service. In the field of CATV network related technology, only those service providers will be able to survive in future, and they can combine available services in the most effective and economical way. This research aims to explain the CATV status of Korea and China and its technology trends. It also analyzes CMC(Cable Modem Concentrator) technology, suggested as one of the high-speed internet technology. CMC technology has the advantages of enhancing the transmission speed while using the existing basic structure of HFC network and expanding service area by adding amplifiers within CMC. The distance between coaxial cables is getting shorter with more concentrated areas in large cities in Korea. However, in China, the demand for long distance transmission service is increasing. CMC technology satisfies both short and long distance service subscribers without any geographical limitations. With these advantages, CMC technology is expected to generate lots of economic benefits if applied for the CATV network in the area of China, Middle East, and Southeast Asia.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.6
• /
• pp.1069-1076
• /
• 2007

DOCSIS 3.0 protocol are proposed to support high-speed cable network DOCSIS 3.0 MAC protocol regulates CM and CMTS channel transfer times through MAP message. So MAP Inter-arrival time is primary factor of network performance. However, standards does not include the details of MAP Inter-arrival Time affecting the performance of MAC protocols for DOCSIS 3.0. In this paper, we evaluated the performance of DOCSIS 3.0 protocol follow in MAP Inter-arrival Time. Based on the evaluation results, we propose the optimal MAP Inter-arrival Time. We found that the protocol shows best performance when the MAP Inter-arrival Time is 0.05sec. The research results can apply to performance element which important for the construction of DOCSIS 3.0 base cable networks.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.5A
• /
• pp.631-639
• /
• 2008

This paper reports the mode shapes of Seohae cable-stayed bridge extracted by TDD technique. In order to record total 72 acceleration points in the vertical direction of the bridge deck, a custom made data acquisition system with LAN communication has been especially developed and a set of ambient vibration tests has been conducted. For the measured acceleration responses, total twenty four mode shapes up to 2Hz has been extracted by TDD technique. The extracted mode shapes include many new modes that have not been identified in the current on-line health monitoring system installed in the bridge. It is confirmed that TDD technique is the most effective in extracting the high resolution mode shapes on a particularly long span bridge.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.16 no.4
• /
• pp.165-170
• /
• 2016

The XLPE(or CV) cables installed to deliver high electric power from generator at the power station have operating for the last 40 years in Korea. In 6-8 years from the time of initial operation, the cables in operation start a deteriorating process, depending on the installation and usage conditions. Some cables, even before 6-8 years from the installation, can cause accidents due to the faulty construction or other inadequate environments. In order to prevent cable accident in advance, the regular auditing of power cables are required. For a systematic realization of surveillance and prevention of accidents, we have invented a measuring device. In this paper, we present the device installed at Korean Western Power Co. Ltd., in order to detect the deterioration status of insulation resistances of dielectrics in the cables. We present that the measured results by the device we developed show the deteriorating processes in the cables in operation.