• Journal of IKEEE
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• v.27 no.4
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• pp.579-586
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• 2023

Device-to-Device communication is a very important essential feature in PPDR(Public Protection Disaster Relief) communication, but it has not yet been implemented in LTE-based PPDR communication. In this study, we propose a solution to implement the LTE-based domestic PPDR communication network by evolving the terminals into D2D in-band terminals and effectively operating the current PS-LTE terminals and digital radios in the transitional period.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.8
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• pp.860-872
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• 2013

In this paper, reasonable and effective building strategies of PPDR network is presented through investigating and analysing current policies for PPDR network of Korea and foreign countries. The research result shows that it is necessary PPDR network is designed and implemented considering currently transient status in aspects of PPDR-related technical roadmaps and existing PPDR networks. Also, in the transient period of more than 5 years, mobile broadband- based private PPDR network should be builded and it should be complemented by some commercial networks such as TRS or other mobile broadband networks.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.209-216
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• 2011

For Effective and systematic response to disasters, needs of broadband multimedia services in wireless communication of PPDR(public protection and disaster relief) is increasing gradually. Recently in Korea, by the digital television transition, Korea Communications Commission is considering whether the freed spectrum can assign additional spectrum of PPDR or not. In this paper, we were defined the input parameters, were estimated the spectrum of requirements for Korean wireless communication of PPDR based on M.1390 methodology recommended by ITU-R.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.10
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• pp.858-864
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• 2012

In South Korea, to effective and systematic response to disasters, the government will build wireless communication network for PPDR(Public Protection and Disaster Relief) on a national level by 2015. To do it, as MOPAS(Ministry of Public Administration and Security) requested the new frequency assignment for PPDR, KCC(Korea Communications Commission) has been examined new frequency allocations about TETRA and WiBro technologies. In this paper, we were defined the technical parameters, were estimated the spectrum of TETRA-TRS requirements for Korean wireless communication of PPDR based on M.2033 methodology recommended by ITU-R.

• Journal of Broadcast Engineering
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• v.20 no.1
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• pp.82-91
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• 2015

The purpose of this paper is to propose the frequency allocation plan for the terrestrial UHDTV in 700MHz frequency band. Currently 700MHz frequency band is being requested by broadcasting, communication, and public safety sites for the use of UHDTV, LTE/LTE-A and PPDR (Public Protection and Disaster Relief) by each site. Validity and proper timing of each request is examined by references, and the frequency allocation plan is proposed. As results 9 channels and guard bands are allocated for the UHDTV service, under the consideration of two 10MHz frequency bands of the PPDR in700MHz band.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.6
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• pp.1266-1272
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• 2013

This paper calculates estimated number of cell sites to build a nationwide PPDR(Public Protection and Disaster Relief) network of WiBro and LTE technical methods through a link budget calculation, presents the efficient technical method through a comparison between the number of cell sites using WiBro and LTE. As a calculation results, the number of cell sites using WiBro method are larger than twice compared to that of LTE method on the same frequency bands, due to the differences of uplink PAPR, uplink transmission technique and SINR. On the basis of the result, LTE mothod is considered as a more effective technology than the WiBro method on the economic, technical and marketing points of views on building a nationwide network.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.31-39
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• 2011

For rapid formed the ad hoc wireless backbone network in disaster scene, It is necessary for real-time deployment scheme of wireless ad hoc relay devices by first responders without pre-planning. However, in order to realize this scheme, redundant deployment should be minimized, as well as optimal location of relay devices should be selected to expand communication coverage. Therefore, in this paper, we propose a new deployment scheme of relay devices to optimize communication coverage and then through simulations showed that improved performance of algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.51-56
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• 2014

TETRA(TErrestrial Trunked RAdio) provide specialized disaster radio communication services as a standard European for digital TRS(Trunked Radio System). Especially, DMO(Direct Mode Operation) feature is used effectively in the radio shadow areas which base station does not propagate radio signal because it can communicate directly with terminal to terminal without base station's relay function. However, to effectively used DMO feature, radio coverage prediction information should be provided to users. Therefore in this paper, we were calculated link budget of TETRA DMO terminals which were distributing and operating in the country and then predicted reaching distance about radio propagation to be applied with path loss model.

• Journal of the Korea Society of Computer and Information
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• v.18 no.3
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• pp.97-105
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• 2013

All means of communication using base stations are interrupted if the scorched earth environment happens because of a disaster. In order to use the systems of the public protection and disaster relief standards, users have to use the special equipments and need the expertise of the operation. Also, it needs the enormous investment for building an infrastructure. The systems is inadequate for the quick and efficient disaster communication, and the people can be in the chaos before the national resources are committed. For solving this problem, this paper presents the design of the mobile application that general people can use immediately, and implements the android phone's application for the proof of concept.

• Journal of the Korea Society of Computer and Information
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• v.19 no.6
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• pp.81-92
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• 2014

In this paper, we propose an efficient dynamic workload balancing strategy which improves the performance of high-performance computing system. The key idea of this dynamic workload balancing strategy is to minimize execution time of each job and to maximize the system throughput by effectively using system resource such as CPU, memory. Also, this strategy dynamically allocates job by considering demanded memory size of executing job and workload status of each node. If an overload node occurs due to allocated job, the proposed scheme migrates job, executing in overload nodes, to another free nodes and reduces the waiting time and execution time of job by balancing workload of each node. Through simulation, we show that the proposed dynamic workload balancing strategy based on CPU, memory improves the performance of high-performance computing system compared to previous strategies.