• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.153-158
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• 2008

The technology of Software Defined Radio (SDR) is a possible solution to interwork flexibly between various wireless transport protocols. Ubiquitous network, like u-health service network, includes sensor devices or nodes which do not facilitate all the same transport protocols to access network. As such this may be in such unreachable situations as poverty of all required AP (Access Point)’s, faults or contention in a path of particular protocol communication, etc. This paper presents research results of modeling and simulation to analyze transport performance of multi-protocol ubiquitous network which includes SDR-based interwork nodes and congestion-controlled AP’s. Focusing mainly on dynamics of overall transport performance rather than protocol execution procedures, this paper employs the Zeigler’s DEVS (Discrete Event Systems Specification) methodology and DEVSim++simulation environment to experiment.

• The Journal of the Korea Contents Association
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• v.13 no.4
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• pp.389-398
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• 2013

This study aims to support rational security investment decision making through prioritizing on operational level of management measures strategically, in carrying out industrial security activities. For this, AHP survey is conducted against industrial security professionals and analyzed. Thereafter, the importance and the priority of industrial security management measures are determined. As a result, in a comparison evaluation among the criteria, 'ICT service management' represents the highest weight (0.54). And the sub-criteria could be divided into three groups (Group I, II, III), depending on their importance. The sensitivity analysis results show that if the weight of the criterion, 'ICT systems/networks access control' is doubled, the sub-criteria, 'O/S access control', 'application access control', and 'wired/wireless network access control' are enter into top rank group. In case of the criterion, 'physical/environmental security' is doubled, the sub-criteria, 'protection zoning/access control' and 'disaster prevention on business equipment/counter-terrorism' are enter into the top rank group, 'securing utilities' is enter into the mid rank group.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.6
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• pp.1551-1560
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• 2016

With the advancement of wearable devices and wireless body are networks, smart healthcare systems based on such technologies have been emerging to effectively monitor patient health and disease progression. In order to implement viable smart healthcare systems, the security and privacy of patient's personal health information must be considered. Yang et al. proposed a privacy-preserving authentication scheme using key-insulation technique for remote health monitoring system, however, key-insulation technique is not properly adapted to their scheme which in turn causes a security pitfall contrary to their assertions. Besides, Yang et al.'s scheme does not guarantee user anonymity against healthcare service provider. Therefore, in this paper, we discuss the security concerns for Yang et al.'s scheme and present an improved anonymous authentication scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1B
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• pp.27-34
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• 2010

As VoIP systems move to wireless environments with much higher average packet loss rates than wired networks, it becomes less possible for the network to assure a reasonable QoS. So, real-time quality monitoring for mobile VoIP applications is an important issue to be explored. In this paper, we explore perceptual quality dependency on two parameters: the burst loss rate and average burst length. Also, we propose a simple 'moving average' approach with $\alpha$ aiming to measure those parameters on real-time basis. In order to find how accurately the two parameters measured estimate the real perceptual quality, we compare actual measured PESQ scores with estimated value by matching the measured quality metric to the trained MOS table. Finally, we propose the quality-based accounting system, which can set obvious continuities between quality and billing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1360-1368
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• 2010

Recently, as the development of Radio Frequency Identification (RFID) technology becomes active, the demand for services which can electronically manage the history and location information of major trees, including trees for cultural heritage restoration and nurse trees, has been increased. This information has been managed by separated drawings and documents or storing its information into PDAs and then structuring data files through input and computation. But, these methods imply limitations in terms of its extensibility and scalability. This paper has designed and implemented an RFID based Tree History Information System (THIS) for cultural heritage restoration. The purpose of the proposed system is to support to be able to effectively and consistently manage historical information of major trees and improve working processes by implementing mobile RFID services through wireless Internet or Local Area Network (LAN) as mobile communication networks. Through implementation, it is confirmed that the proposed system can manage the historical information of major trees more effectively than conventional methods and also improve previous field working conditions.

• Journal of Communications and Networks
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• v.18 no.1
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• pp.50-64
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• 2016

Nowadays, smart meter (SM) technology is widely effectively used. In addition, power allocation (PA) and channel selection (CS) are considered problems with many proposed approaches. In this paper, we will suggest a specific scenario for an SM configuration system and show how to solve the optimization problem for transmission between SMs and the data concentrator unit (DCU), the center that collects the data from several SMs, via simulation. An efficient CS with PA scheme is proposed in the TV white space system, which uses the TV band spectrum. On the basic of the optimal configuration requirements, SMs can have a transmission schedule and channel selection to obtain the optimal efficiency of using spectrum resources when transmitting data to the DCU. The optimal goals discussed in this paper are the maximum capacity or maximum channel efficiency and the maximum allowable power of the SMs used to satisfy the quality of service without harm to another wireless system. In addition, minimization of the interference to the digital television system and other SMs is also important and needs to be considered when the solving coexistence scenario. Further, we propose a process that performs an interference analysis scheme by using the spectrum engineering advanced Monte Carlo analysis tool (SEAMCAT), which is an integrated software tool based on a Monte-Carlo simulation method. Briefly, the process is as follows: The optimization process implemented by genetic evolution optimization engines, i.e., a genetic algorithm, will calculate the best configuration for the SM system on the basis of the interference limitation for each SM by SEAMCAT in a specific configuration, which reaches the solution with the best defined optimal goal satisfaction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1139-1145
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• 2014

In shipyard site, a ship is constructed by integrating lots of modules that are made in several sites with different capabilities and specifications. Recently, it needs to make a shipyard to be smart communicating various multimedia information with wired and wireless broadband networks between hierarchical shipyards. In this paper, we propose an additional function of an LTE femtocell local gateway at a remote shipyard, an information exchange method between hierarchical shipyards, and an offload method to separate the general traffic. To reduce traffic of duplicated requests in shipyard, we apply a D2D communication scheme for supporting communication between shipyard equipments without IP service network. Hence, it is expected to increase the productivity of shipyard industry with mobile communications, D2D and broadband Internet technologies.

• The Transactions of the Korea Information Processing Society
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• v.6 no.9
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• pp.2460-2469
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• 1999

Recently, appearing of various wireless telecommunications services, the competitive power of paging service is requested. In this paper, two-way paging earth station for satellite was proposed and designed to enhance the competitive power of cost and technique, and the link budget of this two-way paging networks using Koreas at was discussed. To reduce the cost of remote station, the antenna and HPA size of Hub and remote station were differently designed, and an idea of power allocations of inbound and outbound carriers was proposed and utilized in this link budget of two-way earth station for using satellite. The results of this link budget were follows. At the 0.043% time rate of rain, antenna size of Hub and remote station were 3.7m and 1.2m, the HPA size of Hub and remote station were 10.37W and 2.0W, and power allocations of outbound and inbound were 84% and 16% respectively. At the 0.02% time rate of rain, the antenna size of Hub and remote station were 3.7m and 1.8m and power allocations of outbound and inbound were 63% and 37% respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3455-3461
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• 2015

LTE and Wi-Fi networks provide wireless communication services to passengers in subway where the number of network access fluctuates according to passenger movement. While the number of network access increase, LTE can provide stable communication service but Wi-Fi suffers temporal access delay to network. This paper analyzes the increase in access delay of Wi-Fi network according to increasing user in subway section by making mathematical modeling of Wi-Fi network and simulation study. The access delay characteristics of Wi-Fi network is measured along an subway line and the results are compared to the theoretical study. These results can be applied to the connection method to build an efficient network structure between LTE and Wi-Fi interworking network and the future introduction of LTE-R.

• Journal of KIISE:Information Networking
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• v.29 no.4
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• pp.333-345
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• 2002

As computers and networks become popular, distributing information on the Internet is common in our daily life. Also, the explosion of the Internet, of wireless digital communication and data exchange on Internet has rapidly changed the way we connect with other people. But secure mail is gaining popularity abroad and domestically because of their nature of providing security. That is. It has been used a variety of fields such as general mail and e-mail for advertisement. But, As the data transmitted on network can be easily opened or forged with simple operations. Most of existing e-mail system don't have any security on the transmitted information. Thus, security mail system need to provide security including message encryption, content integrity, message origin authentication, and non-repudiation. In this paper, we design and implement secure mail system with secure key agreement algorithm, non-repudiation service, and encryption capability to provide services for certification of delivery and certification of content as well as the basic security services.