• Journal of KIISE:Information Networking
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• v.32 no.2
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• pp.180-189
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• 2005

This paper describes a transmission power control method for power saving in 802.11b wireless LANs. We have first explored how much effects reducing transmission power has on communication performance. Then we propose a power control algorithm, whose approach is similar to that of TCP congestion control, determining an appropriate transmission power level by monitoring the retransmission rate. We have implemented an utility software on a Linux-based system and made several experiments to validate the proposed method. The results show that it is possible to save energy consumption by controlling transmission power without sacrificing communication performance.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.6
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• pp.29-46
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• 2002

We generally use SSL/TLS protocol utilizing X.509 v3 certificates so as to provide a secure means in establishment an confidential communication and the support of the authentication service. SPKI/SDSI was motivated by the perception that X.509 is too complex and incomplete. This thesis focuses on designing a secure server and an implementation of the prototype which has two main modules, one is to support secure communication and RBAC, not being remained in the SPKI/SDSI server which was developed by the existing Geronimo project and the other is to wholly issue name-certificate and authorization-cerificate. And the demonstration embodied for our sewer is outlined hereafter.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.5
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• pp.574-580
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• 2016

In this paper, we will introduce the system that can control multiple vehicles on the road through Single Board Computers and V2I (Vehicle-To-Infrastructure). Also, we will propose the group evasive maneuver decision algorithm, which plays a critical role in deciding whether the vehicles in the system have to conduct evasive maneuvers to avoid obstacles on the road. In order to test this system, we have utilized Wi-Fi and TCP/IP for establishing the communication between multiple vehicles and the relay server, and observed their driving states on the road with obstacles. During the experiments, we have discovered that our original decision algorithm possesses high failure rate when there is frequency interference in ISM (Industrial Scientific Medical) band. In order to reduce this failure rate, we have implemented the data transition detector. This paper will focus on how the use of data transition detector can affect the reliability of the system under the frequency interference of ISM band. If this technology is improved and applied in the field, we will effectively deal with such dangerous situations as multiple collision accidents through vehicle-to-vehicle communication or vehicle-to-infrastructure communication. Furthermore, this can be applied to the autonomous driving technologies. This can be used as the reference data for the development of the similar system.

• Journal of information and communication convergence engineering
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• v.20 no.4
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• pp.273-279
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• 2022

Owing to the need to establish a cooperative-intelligent transport system (C-ITS) environment in the transportation sector locally and abroad, various research and development efforts such as high-tech road infrastructure, connection technology between road components, and traffic information systems are currently underway. However, the current central control center-oriented information collection and provision service structure and the insufficient road infrastructure limit the realization of the C-ITS, which requires a diversity of traffic information, real-time data, advanced traffic safety management, and transportation convenience services. In this study, a network construction method based on the existing received signal strength indicator (RSSI) selected as a comparison target, and the experimental target and the proposed intelligent edge network compared and analyzed. The result of the analysis showed that the data transmission rate in the intelligent edge network was 97.48%, the data transmission time was 215 ms, and the recovery time of network failure was 49,983 ms.

• Journal of information and communication convergence engineering
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• v.10 no.4
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• pp.337-342
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• 2012

The medical industries are integrated with information technology with mobile devices and wireless communication. The advent of mobile healthcare systems can benefit patients and hospitals, by not only providing better quality of patient care, but also by reducing administrative and medical costs for both patients and hospitals. Security issues present an interesting research topic in wireless and pervasive healthcare networks. As information technology is developed, many organizations such as government agencies, public institutions, and corporations have employed an information system to enhance the efficiency of their work processes. For the past few years, healthcare organizations throughout the world have been adopting health information systems (HIS) based on the wireless network infrastructure. As a part of the wireless network, a mobile agent has been employed at a large scale in hospitals due to its outstanding mobility. Several vulnerabilities and security requirements related to mobile devices should be considered in implementing mobile services in the hospital environment. Secure authentication and protocols with a mobile agent for applying ubiquitous sensor networks in a healthcare system environment is proposed and analyzed in this paper.

• The Journal of Information Systems
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• v.8 no.1
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• pp.149-176
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• 1999

Regional information infrastructure(RII) plays an increasingly important role in determining the competitiveness of companies operating within the region. The purposes of this research are (1) to identify the types of RII demanded by the companies operating within Pusan and KyungNam areas in Republic of Korea, (2) to explain the levels of RII demand using variables including organizational environment, organizational strategy, and the importance of information systems for the organization, and (3) to examine whether the types of RII demand are different depending on the competition strategies that companies are pursuing. The most important type of RII that region companies demand is information systems personnel having knowledge in systems control, systems planning, communication network, database administration, and system construction. In addition, demanded are TSDN, satellite communication network, and shareable software and hardware. The levels of RII demand are different depending on the importance of information systems(IS) roles for the businesses. The more important IS role is for a company, the more sharable computing equipments and facilities are demanded. The importance of IS role is affected by the organizational environment and organizational strategy. The levels of RII demand are different also depending on the competitive advantages that companies are pursuing. Companies focusing on achieving short-term and direct benefits using information technology tend to have higher demands on sharable computing equipments and facilities as well as on information communication services. This research is explorative in nature One major limitation of this research, therefore, is that the plausibility of the postulated hypotheses was not examined simultaneously. This research is meaningful in that it first attempted to measure the demands of regional companies for RII.

• Convergence Security Journal
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• v.19 no.1
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• pp.61-66
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• 2019

Cyber space is a place where free activities are guaranteed. However, it is also true that not all individuals and countries strive for peaceful cyberspace, and that there is a growing tendency to gain unfair advantage through this space. Therefore, the state should reform laws and institutions to keep cyberspace safe. By establishing the "Basic Law on Cyberspace" which includes the law of the state law on cyberspace, it is necessary to be able to recognize and respond to the direction of the national legal discipline on cyberspace. The development of digital forensics is an urgent task due to the rapid development of IT. However, if the law is delayed for various reasons, some of the existing laws should be amended to improve the stability of the law in accordance with the circumstances. To this end, it is necessary to revise the "Information and Communication Infrastructure Protection Act", "Information and Communication Network Enhancement and Information Protection Act", "Integrated Defense Law", "Establishment of Defense Information Infrastructure Infrastructure and Defense Information Resource Management Act".

• Journal of the Society of Disaster Information
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• v.14 no.2
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• pp.203-210
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• 2018

Purpose: The purpose of this study is to build a model for the meta - evaluation of the national infrastructure system and to improve the evaluation system of the national infrastructure system using the model. Method: For the study, the disaster-related laws and regulations, the evaluation report of the national infrastructure system published by the government, the guideline for the establishment of the national infrastructure protection plan, the meta-evaluation previous research data, To analyze the actual state of the evaluation. Results: Among the indices of evaluation of the current national infrastructure system, the supplementary requirements were derived from seven indicators such as appropriateness of education and training plan and implementation of disaster response, evaluation and communication with stakeholders, and evaluation committee training time. Conclusion: It is expected that the improvement plan derived from this study can be used to improve the evaluation index of the national infrastructure system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.8
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• pp.3766-3788
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• 2017

A blockchain is an underlying technology and basic infrastructure of the Bitcoin system. At present, blockchains and their applications are developing rapidly. However, the basic research of blockchain technology is still in the early stages. The efficiency and reliability of blockchain communication is one of the research problems that urgently need to be studied and addressed. Existing algorithms may be less feasible for blockchain-based communication because they only consider a single communication factor (node communication capability or node trust degree) and only focus on a single communication performance parameter(communication time or communication reliability). In this paper, to shorten the validation time of blockchain transactions and improve the reliability of blockchain-based communication, we first establish a multi-link concurrent communication model based on trust degree, and then we propose a novel integrated factor communication tree algorithm (IFT). This algorithm comprehensively considers the node communication link number and the node trust degree and selects several nodes with powerful communication capacity and high trust as the communication sources to improve the concurrency and communication efficiency. Simulation results indicate that the IFT algorithm outperforms existing algorithms. A blockchain communication routing scheme based on the IFT algorithm can increase communication efficiency by ensuring communication reliability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.3
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• pp.283-293
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• 1998

The numbering plan, basic requirements for interworking standards, and technical standard specification for National Information Infrastructure have not been defined specifically yet. It is reviewed for the numbering plans of public/private ATM networks based on the standard specifications of W-T and ATM Forum. The specifications for numbering plan are discussed for the interworking between current various networks and National Information Infrastructure based on the related standard specification of ITU-T and ATM Forum.