• Journal of Information Management
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• v.38 no.1
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• pp.141-160
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• 2007

Many contents produced and provided as development of information technology on the internet. Especially discussion that collecting and storing of digital information resources, is expanded as growing dependence on academic information of research workers. Open Access is a new paradigm of information distribution that is opposite concept of high price distribution academic information. It is an OAI system that is intended to collect and automate open access data in good order. This paper constructs stOAI based on OAI that is a science and technology information providing system. This system provides international academic journal free of charge that collect and store through OAI protocol in OA(Open Access) of yesKISTI(science and technology information portal service). Also, It provides automate and centralize science technology information, that KISTI has, to external institution as a standard type.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.3
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• pp.713-720
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• 1996

In recent, the demand of mobile communication system is increasing rapidly. However, since wireless resources is limitted, the protocol to utilize wireless resource efficiently is needed. Up to now, Slotted CDMA_ALOHA(S_CDMA_ALOHA) and Mini-Slotted CDMA_ALOHA(MS_CDMA_ALOHA) methods are proposed as a CDMA_ALOHA mechanism, and it is turned out that MS_CDMA_ALOHA offers betterperformance than S_CDMA_ALOHA mechanism. Also, IS-95 multiple access mechanism has been proposed as common air interface(CAI) protocol of CDMA digital cellular system. However, in former study, the performance evaluations were made without considertion of chnnel characteristics of wireless communication environment. In this paper, a new access mechanism for improring the performance in the DS/CDMA digital cellular environment is suggested. This mechanism is adaptive to the channel condition and based on the conventional MS_CDMA_ALOHA mechanism. Also, the performance of new access mechanism is compared with that of conventional mechanisms, through computer simulation. According tot h simulation results, it is shown that the proposed NA_CDMA_ALOHA(Noise-Adaptation CDMA_ALOHA) mechanism offers better performance than conventional three CDMA_ALOHA mechanisms in view of mean delay time and system throughput characteristics. This phenomenon is due to the fast that NA_CDMA_ALOHA mechanism controls the access attempts efficiently based on the channel condition in heavy traffic environments.

• Convergence Security Journal
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• v.8 no.4
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• pp.65-71
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• 2008

According to the capacity of hard disk drive is increasing day by day, the amount of data that forensic investigators should analyze is also increasing. This trend need tremendous time and effort in determining which files are important as evidence on computers. Using the file system APIs provided by Windows system is the easy way to identify those files. This method, however, requires a large amount of time as the number of files increase and changes the access time of files. Moreover, some files cannot be accessed due to the use of operating system. To resolve these problems, forensic analysis should be conducted by using the Master File Table (MFT). In this paper, We implement the file access program which interprets the MFT information in NTFS file system. We also extensibly compare the program with the previous method. Experimental results show that the presented program reduces the file access time then others. As a result, The file access method using MFT information is forensically sound and also alleviates the investigation time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.11
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• pp.652-659
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• 2014

In this paper, we propose an access point selection method for mobile users in LTE-femtocell system. In wireless communication system, users want to receive good data service. In LTE-femtocell system, if users move a little, users can experience different data service. The proposed access point selection method help that if users move a little, users obtain the high capacity and that user selects access point that other user have not selected much and so obtains higher data service. We simulated in order to prove performance of the proposed access point selection metod. Simulation results show that in a situation that users are concentrated in order to obtain better data service users are seen scattered look. As a result, we confirm that the proposed access point selection method provides good data service to users.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7B
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• pp.760-770
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• 2011

The existing mobility management schemes do not fully support the next generation network, which is composed of IP-based core network and various access networks. Currently, ETRI has been developing the AIMS (Access Independent Mobility Service) system which satisfies the ITU-T requirements of mobility management in the next generation network. The AIMS system is designed to provide a mobile host with a fast and reliable mobility service among heterogeneous access networks. Recently, many user devices have multiple communication interfaces, e.g., 3G and WLAN, and thus they can make two or more network connections at the same time. In this paper, we design a scheme of flow mobility, i.e., the movement of selected data flows from one access technology to another, to be applied in the AIMS system, and verify the proposed scheme through the NS-3 simulation study. From the simulation results, we can know that the proposed flow mobility scheme can utilize the network resource efficiently in the heterogeneous mobile networks.

• Journal of IKEEE
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• v.27 no.4
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• pp.548-555
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• 2023

With the advancement of the internet, the use of personal information in online interactions has increased, underscoring the significance of data protection. Breaches of personal data due to unauthorized access can result in psychological and financial damage to individuals, and may even enable wide-ranging societal attacks aimed at those associated with the victims. In response to such threats, there is active research into security measures using blockchain to safeguard personal information. This study proposes a system that uses middleware and IAM (Identity and Access Management) services to protect personal information in a BaaS (Blockchain as a Service) environment where blockchain is provided via the Internet. The middleware operates on servers where IAM roles and policies are applied, authenticates users, and performs access control to allow only legitimate users to access blockchain data existing in the cloud. Additionally, to understand the impact of the proposed personal information protection method on the system, we measure the response time according to the time taken and the number of users under three assumed scenarios, and compare the proposed method and research related to personal information protection using blockchain in terms of security characteristics such as idea, type of blockchain, authentication, and confidentiality.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1349-1355
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• 2016

It should guarantee high reliability and ultra low latency communication. Additionally, it should support connection between massive devices. As one of estimated scenarios for 5G mobile communication, mobile devices and sensors using low data rate wireless communication will increase. For communication of these devices, single-carrier system can be considered. In order to satisfy these requirements, in this paper, we propose CDMA (Code Division Multiple Access) system using complex spreading and Multi-level BPSK(Binary Phase Shift Keying). The proposed system spread transmit symbol by using chip code consisted of real and imaginary number. As simulation results, we can confirm that although the proposed system has 3dB lower BER (Bit Error Rate) performance than conventional CDMA system, the proposed system can support 2 times more users in comparison with conventional CDMA system.

• International journal of advanced smart convergence
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• v.5 no.3
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• pp.66-71
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• 2016

Smart building gate security control system using smartphone integrated with near field communication (NFC) has become part of daily life usage these days. The technology change in replacing RF NFC device using visible light communication technology based approach growing faster in recent days. This paper propose a design and development of gate security control system using color code based user authentication ID generation as part of an intelligent access control system to control automatic door open and close. In this approach gate security access control use the recent visible light communication technology trends to transfer the user specific authentication code to door access control system using color code on smartphone screen. Using a camera in the door access control system (ACS), color codes on smartphone screens are detected and matched to the database of authenticated user to open the door automatically in gate security system. We measure the visual light communication technology efficiency as a part of the research and the experiments have revealed that more than 95% users authenticated correctly at the suggested experiment environment on gate security control system.

• Journal of Convergence Society for SMB
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• v.6 no.3
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• pp.29-35
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• 2016

This paper presents the design of a user authentication system (DCIAS) using the device constant information. Defined design a new password using the access device constant information to be used for user authentication during system access on the network, and design a new concept the user authentication system so that it can cope with the threat required from passive replay attacks to re-use the password obtained in other applications offer. In addition, by storing a password defined by the design of the encrypted random locations in the server and designed to neutralize the illegal access to the system through the network. Therefore proposed using the present system, even if access to the system through any of the network can not know whether any where the password is stored, and if all right even stored information is not easy to crack's encrypted to neutralize any replay attacks on the network to that has strong security features.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.722-724
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• 2010

CAS(Conditional Access System) was developed for paid-for service in cable and fixed satellite broadcast system and technology and market maturity are high. However, these assessment is limited by CAS in fixed broadcasting system. In case of digital mobile broadcast such as T-DMB is difficult to apply CAS technology of fixed broadcasting system because of a use method and technology characteristic. Expecially, in case T-DMB using limited resources, a CAS message which must transmit in each service channel can cause problems. It is desirable that system transmits the CAS message which transmitted by each service channel through logical CAS message-only channel. In order to make a logical CAS message channel, we need a multiplexing techniques for CAS message using in each channel. In this paper, we design the CAS message multiplexing techniques for composition of CAS message-only channel.