• ETRI Journal
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• v.26 no.3
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• pp.265-268
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• 2004

We develop a simple exact solution method for return link capacity allocation scheduling in a satellite interactive network using a hybrid code-division multiple access / time-division multiple access (CDMA/TDMA) scheme.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.39-45
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• 2010

Most traffic in the real internet is TCP traffic. Therefore newly proposed network coding schemes must consider their effects on TCP performance. However, in most studies on network coding, performance evaluation has been conducted using other types of traffic than TCP traffic because network coding has effects on the pattern of packet transmission, which again can impact TCP performance. In most packet transmission schemes based on network coding for wireless mesh networks, it is determined which node, among the ones that received a broadcasted packet, should encode and forward it. In this paper, we examine how the forwarder nodes impact TCP performance.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.144-150
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• 2020

Reinforcement learning is a technology that can present successful and creative solutions in many areas. This reinforcement learning technology was used to deploy containers from cloud servers to fog servers to help them learn the maximization of rewards due to reduced traffic. Leveraging reinforcement learning is aimed at predicting traffic in the network and optimizing traffic-based fog computing network environment for cloud, fog and clients. The reinforcement learning system collects network traffic data from the fog server and IoT. Reinforcement learning neural networks, which use collected traffic data as input values, can consist of Long Short-Term Memory (LSTM) neural networks in network environments that support fog computing, to learn time series data and to predict optimized traffic. Description of the input and output values of the traffic-based reinforcement learning LSTM neural network, the composition of the node, the activation function and error function of the hidden layer, the overfitting method, and the optimization algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.169-175
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• 2011

This paper addresses mobile IP router which communicate between nodes in Ad Hoc network as well as supply attachment to outer Internet. Ad Hoc network is one which exchanges information through cooperations among nodes without wire infrastructure, mobile IP router considers the network as one mobile unit, and supports Internet connection in mobile as well as fixed spaces. Therefore, this router can accommodate the routing of Ad Hoc network, and provide nodes in Ad Hoc network with Internet connection. So mobile IP router can provide Ad-Hoc terminals with the diverse wireless services, such as Internet connection service, routing, mobility, and so on.

• Journal of Broadcast Engineering
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• v.13 no.4
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• pp.463-478
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• 2008

A Distributed Translator Network(DTxR) is a cost-effective and frequency-effective method which can use existing transmission utilities and can be constructed in a shorter time as compared with Multiple Frequency Network(MFN) or Single Frequency Network(SFN) using On Channel Repeater(OCR). In order to verify the feasibility of DTxR, this field test was done in 30 points of north-west area in Seoul using 3rd, 5th, and 6th generation DIV receivers. Electric field strength, noise margin and ease of reception were measured and subjective evaluation of video quality was done in these points during the field test. With the test result, an improvement of receiving quality was obtained and an ease of reception was increased in case of the 5th. and 6th. receiver. From the results, we conclude that DTxR is a feasible method in DIV networks.

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.58-62
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• 2012

Emergency alerting broadcasting of T-DMB is being serviced to deliver the event of a disaster to the people quickly and effectively through a T-DMB network. DGPS has been developed in order to improve the accuracy of the GPS receiving data and transmitting of DGPS information through the T-DMB network is being studied for a wide range of usage. Because DGPS information and AEAS message are sent through the same T-DMB network, if DGPS information is applied to AEAS message disaster area can be specified more precisely and the exact location of the disaster can be measured in the terminal. In this paper, a implementation method of T-DMB emergency alerting broadcasting system based on a DGPS including a new structure of AEAS message was proposed to identify the location of disaster accurately.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.531-534
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• 2010

Currently the functionality of the PRC-999K radio that is widely used in Korean Army is half-duplex and the broadcasting system that all subscribers have to listen when one subscriber speaks in time. Radio data communication system configures peer-to-peer network between command post and network members in military fire control system. And the system applies CSMA/CA(Carrier Sense Multiple Access/Collision Avoidance) technique to avoid data collision. Such a data transmitting/receiving time could be reduced by allocating address in serial order to each network members. By doing that, command post need to broadcast data only one time and assigned members will reply in order without data collision. This paper provides such a protocol and algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.197-203
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• 2011

Ad-hoc networks do not rely on a preexisting infrastructure such as Access Points(AP) in wireless network infrastructure. Instead each node participates in routing by forwarding data for other nodes. It makes required broadcasting to transmit packets to the whole network. In that part, each node tries to transmit data without any information about the other nodes. Therefore it causes duplication of transmission and waste of power. This paper presents adaptive probabilistic broadcasting schemes based on packet reception counts to alleviate the broadcast storm problem for wireless ad hoc networks. In this algorithm, each node calculates efficiency broadcast probability. Simulation results for the proposed flood algorithm are also presented.

• Journal of Korea Multimedia Society
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• v.21 no.3
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• pp.415-422
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• 2018

Advances of telecommunication technology bring various changes in journalism field. Reporters started to gather, edit, and transmit content to main server in media company using hand-held smart media and notebook computer. This paper tried to testify valid bit-rate of visual news content using LTE network and mobile phone. Field news like natural disasters need real-time transmission of video content. But broadcasting company normally use heavy ENG system and transmission satellite trucks. We prepared and experimented different types of visual content that has different bit-rates. Transmission tool was LU-60HD mobile system of LiveU Corporation. Transmission result shows that bit-rate of 2Mbps news content is not suitable for broadcasting and VBR (Variable Bit Rate) transmission has better definition quality than CBR (Constant Bit Rate) method. Three different bit-rate of VBR transmission result shows that 5Mbps clip has better quality than 1Mbps and 3Mbps. The higher bit-rate, the better video quality. But if the content has much movements, that cause delay and abnormal quality of video. So optimizing the balance between stability of signal and quality of bit-rate is crucial factor of real-time broadcasting news gathering business.

• ETRI Journal
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• v.38 no.1
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• pp.112-122
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• 2016

This paper presents a set of candidate regulatory requirements for TV band devices (TVBDs) in the Rep. of Korea. To guarantee the protection of incumbent services, especially digital TV (DTV) and wireless microphones, in TV frequency bands, we suggest minimum separation distances of TVBDs from the noise-limited contour according to incumbent users and TVBD types. This paper also deals with multiple sets of separation distances of a co-channel TVBD network from a DTV protected contour on the basis of the radio propagation characteristics of different geographic areas to make good use of TV white space (TVWS) and safely protect the DTV service. We present a low-power transmission mode of TVBDs and the relevant separation distances for small-cell deployment. The service coverage reduction ratio of a TVBD network is investigated in the presence of DTV interference in four geographic areas. The TVWS field verification results, conducted on the island of Jeju (Rep. of Korea), show that incumbent services operate well without harmful interference from neighboring TVBDs with the proposed separation distances.