• Journal of KIISE:Information Networking
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• v.29 no.1
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• pp.77-85
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• 2002

The surge in use of networks has recently increased demands for cryptography. Cryptography, however, can cause various problems because of difficulty of key management. A lot of researchers have been concentrating on the key recovery technique to eliminate the reverse effect of using these kinds of security and to promote positive aspects of using it. They have suggested many key recovery techniques up to the present. we propose a mechanism as a solution, which are employed to reduce the time needed to reconnect SG and the host in Host-to-Gateway in VPNs supporting IPsec, in case they are disconnected. This new mechanism using KRFSH stores information at each session in advance so that users can recall the session information when needed to rebuild the tunnel between SG and the host in a VPN. As a result, the mechanism built into SG will solve the problems above in host-to-gateway VPNs using IPsec.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8B
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• pp.699-706
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• 2003

This paper is to verify that 2-state MMPP Model conform to ATM VBR traffic characteristics by measuring and analyzing real-time VBR traffic in KT's ATM network. As a result, we validated the fact that real-time VBR traffic of ATM network cannot be apply to MMPP model and must be represented by previously general On-Off Model with characteristics as follows: arrival rate of On state (λ$_1$) is deterministic, arrival rate of Off state (λ$_2$) is zero, and two transition rate (T$_1$,T$_2$) is only random variable. As research results are to handle real traffic, these results can be used to all ATM network traffic model with traffic management function such as KT's ATM network.

• Journal of Distribution Research
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• v.15 no.3
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• pp.35-69
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• 2010

Successful management of distributors is crucial for the success of multi-level marketing (MLM) because MLM sells products and services through distributor networks. The present study examines the impact of the up-line distributors' transformational leadership on down-line distributors' entrepreneurship, market orientation, and performance. The proposed research questions were examined based on a survey of 135 down-line distributors working at the largest domestic MLM company. A mediation mechanism was found that the up-line distributors' transformational leadership increases the down-line distributors' entrepreneurship and market orientation, which in turn influences their performance. Based on the findings, the present study suggests the importance of transformational leadership in MLM. Practical implications for the roles of transformational leadership and its impact on corporate management in specific business areas are also discussed.

• Journal of Navigation and Port Research
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• v.32 no.6
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• pp.473-479
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• 2008

Recently the trade patterns of the entire economy are rapidly changing on development of IT. The field of port logistics is enforcing a competitiveness through preliminary offer of information and a batch process for improving the structure of logistics management which is apparently high cost and the low efficiency since 1990. But a previous EDI is insufficient in process ability. Bemuse it costs for the purchasing and maintenance of the expensive communication devices which is operated on the VAN environment. A web based EDI operating on an open network environment is needed to improve these problems and to handle transaction efficiently among many and unauthorized personals. Therefore, this study is willing to present a new web based model of the pull process which extracts the data when the receiver is needed to improve the push process which is transmitting data unilaterally.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.338-341
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• 2014

Recently, many research efforts have paid attention to spectrum pooling meshanism that provides efficient way to manage transient spectrum requests of secondary users in cognitive radio networks. Spectrum pooling is maintained by WSP (wireless service provider). WSP leases the spectrums stored in her spectrum pool to secondary users with being paid for it. It is natural that WSP tries to get profits as much as possible, which implies the WSP tries to minimize the cost required for maintaining her spectrum pool. In this paper, we model the spectrum pool into a probabilistic inventory model. Assuming secondary users' spectrum requests follow normal distribution, we give a strategic way that minimizes the maintenance cost of the spectrum pool. By a series of simulations, we show that WSP can reduce the total maintenance cost through our inventory model-based spectrum pooling than maintaining fixed inventory level.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.100-103
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• 2019

Due to the fourth industrial revolution called 'fusion and connection', interest in 'high connectivity society' and 'highland society' is increasing, and related objects are not limited to automation and connected cars. The Internet of Things is the main concern of the 4th Industrial Revolution and it is expected to play an important role in establishing the basis of the next generation mobile communication service. Several domestic and foreign companies have been studying various types of LPWANs for the construction of the Internet based on things, and there is Semtech's LoRaWAN technology as representative. LoRaWAN is a long-distance, low-power network designed to manage a large number of devices and sensors, with communications from hundreds to thousands to thousands of devices and sensors. In this paper, we analyze the optimum node capacity of gateway for maximum performance while reducing resource waste in using LoRaWAN.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.13-21
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• 2019

The restricted network or the unbalanced distribution of spectrum is causing the problems of lack of spectrum resources and deterioration of the service quality. In addition, the existing centralized radio sharing method has not been a fundamental solution for radio sharing and is inefficient in terms of cost, convenience, and security. In this paper, we propose a blockchain-based spectrum sharing as a low-cost, trustworthy, high-efficiency platform that can distribute and share spectrum resources, and propose policies to realize this. In the spectrum sharing platform, spectrum information about Wi-Fi AP and LTE mobile hotspot is registered in the blockchain, and spectrum sharers and users can conclude peer-to-peer spectrum sharing contract quickly and efficiently through smart contract. The pay for the shared spectrum resources and reward for spectrum quality management open platform ecosystem to activate the circulation-sharing and it can provide a convenient and efficient public wireless infrastructure.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.2
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• pp.283-293
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• 2012

A new type of malware that extracts personal and account data over an extended period of time and that apparently is resistant to detection by vaccines has been identified. Generally, a malware is installed on a computer through network-to-network connections by utilizing Web vulnerabilities that contain injection, XSS, broken authentication and session management, or insecure direct-object references, among others. After the malware executes registration of an arbitrary service and an arbitrary process on a computer, it then periodically communicates the collected confidential information to a hacker. This paper is a systematic approach to analyzing a new type of malware called "winweng," a kind of worm that frequently made appearances during the first half of 2011. The research describes how the malware came to be in circulation, how it infects computers, how its operations expose its existence and suggests improvements in responses and countermeasures. Keywords: Malware, Worm, Winweng, SNORT.

• Journal of the Korean Society for Library and Information Science
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• v.55 no.1
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• pp.343-364
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• 2021

In this study, as examples of domestic libraries currently using the cloud-based library system, the main characteristics and issues that appeared in the experience of use divided into the processes of introduction, conversion, and operation of each system were investigated, and the results are as follows. First, it is said that new systems were introduced as alternatives to problems caused by the operation of the existing system, and the current products were selected because they were cost-effective. Second, the main issues in the conversion process were data migration work, implementation of existing service functions, and linking problems of internal and external systems in the library. Third, the main advantages identified in the operation process were cost reduction, simple installation and automatic management and maintenance, and convenient use in mobile devices. The main drawbacks were the difficulty of customizing that reflects the characteristics of the library, and the need for stability of the network. The disappeared role of the information technology librarian is the regular system inspection and maintenance support, and various new roles have been suggested. The responses of librarians and users to the new system were generally satisfied rather than dissatisfied.

• 한국노년학
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• v.41 no.3
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• pp.353-371
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• 2021

The purpose of this study is to provide clues to social welfare policy making by revealing discourse on social intervention and response based on big data on elderly living alone in the COVID-19 situation. Keyword analysis, network analysis, and topic analysis were utilized to explore the ways in which news media have portrayed challenges facing older individuals and the ways in which the central and local government as well as private organization have responded to them. Results are as follows. First, networks(degree, closeness, betweenness) were formed around region, delivery, society, support, and vulnerability, suggesting an increased demand for economic assistance and social support as well as stronger service delivery systems. Second, key topics derived included "establishing public delivery systems", "establishing local networks", "Managing care gap", "Establishing a private economic support system", and "Establishing service organization system". Based on the research results, discourse on the organic role of government, communities and the private sector has been presented, suggesting policy and practical implications by proposing a discussion on how to intervene for elderly living alone in disaster situations such as COVID-19.