• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.5
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• pp.201-208
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• 2010

Mobile Ad Hoc Network(MANET) has highly dynamic topology, hence presents a great challenge on the network performance evaluation and network protocol design. We proposed total path break up time, $\sum_{i}T_i$, as a metric to measure the performance of the total system as well as an individual connection. In this paper, we evaluate and analyze the performance of three mobility models(Random Waypoint, Manhattan, Blocked Manhattan) by applying the total path break up metric, investigate why network parameters such as packet delivery ratio, end-to-end delay, etc. vary by mobility models. We also present analysis result how much AODV Buffer improve packet delivery ratio and increase the end-to-end delay in spite of the path break up.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.4
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• pp.35-42
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• 2008

Since Bianchi's 2-D Markov Chain Model considers collision problem only in ideal channel condition, it does not reflect real channel impaired by fading, interference, and noise. Distributed Coordination Function(DCF) doubles its contention window(CW) when transmission fails regardless of collision or transmission error. Increase of CW caused by transmission error degrade throughput and increase the delay. In this paper, we present quantitative analysis of the impact of the parameters such as contention window size(CW), transmission probability for a given time slot(${\Im}$), transmission failure probability($p_f$), on the system performance and provide a method how to decrease the initial CW to achieve equivalent performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.6
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• pp.17-22
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• 2013

Heterogeneous radios are used in disaster management agencies for a variety of reasons though the radio must have the same radio frequency and protocol for voice communication. For this reason, the variety of heterogeneous radio voice connection methods have been studied but these are simple analog voice line cross connection or partial networked based on digitalization. In this paper, we suggest the method of voice packet transmission method based on All-IP per radio through IP network using SIP/RTP for scalability and openness and developed a prototype of the proposed method was verified.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.1
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• pp.151-157
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• 2018

This paper presents an implementation of a smart plant pot which can supply light and water automatically according to the result of detection on current temperature, humidity and illumination, and deliver the images of the plant realtime by using a camera installed in the pot. We designed a container of the plant pot divided into five layers, printed each of them with a 3D printer, and then assembled them. Inside of the container, we installed sensors, a pump, and a camera. We developed an Android application so that the user can control the plant pot and monitor its state. In communication between the Android application and the Raspberry Pi, MQTT protocol was utilized.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.5
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• pp.499-504
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• 2016

The Service had a purpose to be heard through the Smart Phone APP and Smart TV Broadcasting Contents to Foreigner's Language in The Asia Culture Center. This Paper explained how to realize foreigner with Beacon's Signal and IoT gateway provided the voice service with selected his language using AllJoyn Protocol Interface function. IoT Service Platform received the Registration of foreigner's identifier, there sent messages to all devices, which were all IoT gateways, IoT gateway could connect to foreigner's Smart Phone App and heard the Broadcasting contents. If a foreigner went out of Beacon's management distance, the voice App service were released.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.51-55
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• 2015

In this paper, we proposed scheme that obtain diversity gain in the cooperative communication to mitigate, applied to the effects of fading in the vehicle communication. Relay used bus that can available in the city environment. In addition, we applied the double rayleigh fading environment so that can applied in real-environments. Therefore, proposed scheme through this paper applied to vehicle communication, user can acquire a high quality service and the operation efficiency of the network is improved. Finally, performance of the proposed protocol is analyzed in terms of bit error rate.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.4
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• pp.141-145
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• 2012

In a Ubiquitous sensor network environment, the sensor node is in general small and low price, and operating with power limited battery. The reliable TCP/IP protocol is used for transmitting sensed data from the sensor node. A new method was proposed in order to overcome the limitation of small embedded memory, but it is difficult to use for the case of frame error. In this paper, a new algorithm is proposed to manage the receiving frame error or loss, and it is appropriate to the sensor network to send sensed data periodically.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.5
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• pp.125-129
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• 2016

This study has a purpose of development of mobile health monitoring system for measuring, saving and transmitting health signals by standardizing and encoding methods under the mobile environment. The system consists of a module for measuring the health signals with Bluetooth function, encoding equipment for encoding the measured health signals by a standardized encoding method so as to maintain mutual compatibility between devices, and a mobile system for saving and transmitting the encoding health signals. The proposed system was realized under the mobilet environment and has showed to be able to make good use.

• Journal of the Korea Society of Computer and Information
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• v.10 no.2 s.34
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• pp.169-177
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• 2005

The Conditional Access System is a complete system for ensuring that broadcasting services be accessible to only those who are entitled to receive them. Secure key management and efficient delivery mechanism are very important design factors to this system. In this paper, we propose secure and efficient protocols which would be well fitted to a Pay TV system including the satellite DMB. Further. by applying our protocol to the existing conditional access system, we propose a new system that properly enables the control of conditional access to the Pay TV in satellite DMB environment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.209-214
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• 2016

IEC 61850 is a protocol used to reduce the cost of design, installation and maintenance of the Substation Automation System. GOOSE traffic used in IEC 61850 plays an important role for control, protection and automation of the substation. This study implemented a GOOSE traffic generator using the emulation function of NS-3 network simulator, by using protocols provided by a network simulator and another protocols provided by real communication equipment. The generated GOOSE traffic was analyzed with Wireshark, and it was found that the traffic was generated exactly as expected. Besides, this study measured the GOOSE traffic delay due to the increase of the number of switches according to network topology. It is expected that the GOOSE traffic generator implemented by this study will be efficiently used when experiments are performed on actual substation environments.