• The KIPS Transactions:PartC
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• v.11C no.4
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• pp.519-526
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• 2004

This paper presents an efficient interoperation scheme of a VPN(Virtual Private Network) and Mobile IP using a hierarchical structure of a FA(Foreign Agent). In the proposed scheme, the GFA(Gateway Foreign Agent) plays a role of VPN gateway on behalf of the MN(Mobile Node). When the MN moves in the same GFA domain, because the GFA has already an IPsec security association with a VPN gateway in the home network of the MN, the MN does not need an IPsec re-negotiaion. In this way, our mechanism reduces a message overhead and a delay resulted from an IPsec negotiation. And a MN can send a data to a correspondent node without a packet leakage. We show a performance of our scheme by using a discrete analytical model. Analytical results demonstrated that the total processing cost calculated by a registration update cost and a packet delivery cost is significantly reduced through our proposed scheme.

• Journal of KIISE
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• v.44 no.4
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• pp.344-351
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• 2017

An attribute based signature system is a cryptographic system where users produce signatures based on some predicate of attributes, using keys issued by one or more attribute authorities. If a private key is leaked during signature generation, the signature can be forged. Therefore, signing operation computations should be performed using secure hardware, which is called tamper resistant hardware in this paper. However, since tamper resistant hardware does not provide high performance, it cannot perform many operations requiring attribute based signatures in a short time frame. This paper proposes a new attribute based signature system using high performance general hardware and low performance tamper resistant hardware. The proposed signature scheme consists of two signature schemes within a existing attribute based signature scheme and a digital signature scheme. In the proposed scheme, although the attribute based signature is performed in insecure environments, the digital signature scheme using tamper resistant hardware guarantees the security of the signature scheme. The proposed scheme improves the performance by 11 times compared to the traditional attribute based signature scheme on a system using only tamper resistant hardware.

• The Korean Journal of Applied Statistics
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• v.28 no.1
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• pp.103-114
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• 2015

The role of small and medium enterprises as an economic growth factor has been accentuated; consequently, the need to develop a business forecast model and indexes that accurately examine business situation of small and medium enterprises has increased. Most current business model and indexes concerning small and medium enterprises, released by public and private institutions, are based on Business Survey Index (BSI) and depend on subjective (business model and) indexes; therefore, the business model and indexes lack a capacity to grasp an accurate business situation of these enterprises. The business forecast model and indexes suggested in the study have been newly developed with Principal Component Analysis(PCA) and weight method to accurately measure a business situation based on reference dates addressed by the National Statistical Office(NSO). Empirical studies will be presented to prove that the newly proposed business model and indexes have their basis in statistical theory and their trend that resembles the existing Composite Index.

• Journal of the Korean Society for Marine Environment & Energy
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• v.20 no.2
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• pp.117-125
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• 2017

SNS Big-data Analysis means to find potential value from big data which has produced by the social media. In this paper, SNS Big-data has been analysed to find Korean concerns by using 24 key words from the marine and fisheries sector. Among 24 key words, seafood, shipping and Dokdo Island are the most mentioned ones. Some key words such as ocean policies and marine security that have less concerns have bess mentioned less. Also, key words that are led by government are mostly mentioned by news media, but key words that are led by private sector and have intimate relationship with people's lives are mostly mentioned by Blogs and Twitters. Therefore, reflecting close national concerns by SNS Big-data Analysis and especially resolving negative factors are the most significant part of the policy establishment. Also, differentiated promotion methods need to be prepared because the frequency of key words mentioned from each type of media are different.

• Journal of Communications and Networks
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• v.17 no.1
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• pp.75-83
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• 2015

In mobile ad-hoc networks (MANETs), nodes are mobile in nature. Collaboration between mobile nodes is more significant in MANETs, which have as their greatest challenges vulnerabilities to various security attacks and an inability to operate securely while preserving its resources and performing secure routing among nodes. Therefore, it is essential to develop an effective secure routing protocol to protect the nodes from anonymous behaviors. Currently, game theory is a tool that analyzes, formulates and solves selfishness issues. It is seldom applied to detect malicious behavior in networks. It deals, instead, with the strategic and rational behavior of each node. In our study,we used the dynamic Bayesian signaling game to analyze the strategy profile for regular and malicious nodes. This game also revealed the best actions of individual strategies for each node. Perfect Bayesian equilibrium (PBE) provides a prominent solution for signaling games to solve incomplete information by combining strategies and payoff of players that constitute equilibrium. Using PBE strategies of nodes are private information of regular and malicious nodes. Regular nodes should be cooperative during routing and update their payoff, while malicious nodes take sophisticated risks by evaluating their risk of being identified to decide when to decline. This approach minimizes the utility of malicious nodes and it motivates better cooperation between nodes by using the reputation system. Regular nodes monitor continuously to evaluate their neighbors using belief updating systems of the Bayes rule.

• Korean Journal of Childcare and Education
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• v.8 no.1
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• pp.5-24
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• 2012

The purpose of this study was to investigate the cognition on community childcare policy and childcare service needs between working mothers and non-working mothers using the 2008 Child Panel by Korea Childcare Policy Institute. The participants were 654 working mothers and 1,416 non-working mothers. The data were analyzed by $x^2$. The results were as follows; 1) 50% of working mothers and non-working mothers thought that the number of childcare centers was enough. Forty-five percent of working mothers and non-working mothers recognized that the number of kinder gartens and private education institutes was enough. Fifty-two percent of working mothers and 4 5% of non-working mothers thought that use of public leisure facilities were convenient. Twenty-seven percent of working mothers and 20% of non-working mothers thought that use of culture institutes were easily accessible. About 50% of working mothers and non-working mothers felt safe about public security and community safety. 2) Second, working mothers perceived social support higher than non-working mothers in several areas.

• International journal of advanced smart convergence
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• v.10 no.3
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• pp.113-121
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• 2021

This study was conducted on 1,174 retirees in their 50s and 60s nationwide using the 7th data of the National Pension Service's National Elderly Security Panel Survey. We were able to confirm the following results through the SPSS WIN 18.0 program.. First, men showed a higher level of education than women. From these results, it is expected that men will be better prepared for retirement. Second, men had spouses and two or more household members than women. According to previous studies showing that men are better prepared for retirement if they have a spouse, it is expected that men are better prepared for retirement. Second, 38% of men and 62% of women were voluntary retirees. Third, both men and women responded that their own and spouses should play the main role in preparing for retirement. Fourth, both men and women had very low rates of preparation for old age, economic independence, and public and private pensions. Among them, women were lower than men. Fifth, economic problem solving, health, and medical care were the priority as parts to be done for retirement in oneself and society. Based on these results, the directions for preparing retirees for retirement are as follows. First, education on wage peak system, retirement age extension and financial management for involuntary retirees is required, and guidance and management methods on health care and disease should be provided to address needs for health and health care. Women had more voluntary retirees than men, and they need to know why. Second, when both men and women are very poor at preparing for retirement, there should be job creation measures to ensure that they and their spouses are fully prepared for retirement.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.105-114
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• 2014

There are many studies on the adoption intentions for mobile banking. But there are no apparent effect on the popularity of it. This is so because the users have resistance to innovation on Mobile Banking. Therefore, it is necessary to identify empirically the problem of user resistance. In this paper, we identified hindrance factors of mobile banking with previous papers. And then we conducted empirical study by survey reply from undergraduates and graduate students in China. The results of this study are as follows. Social Influence and Perceived Complexity have positive effect on Perceived Risk, and Trust has negative effect on Perceived Risk. Perceived Security and Perceived Protection of Private information have no effect on Perceived Risk. Perceived Risk has effect on User Resistance. The significance of this paper is that financial institutions and telecommunications companies of China could potentially establish new and more accurate strategies based on the resistance factors identified in this paper to gain more profits.

• Journal of Service Research and Studies
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• v.2 no.2
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• pp.53-79
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• 2012

According to Electronic Times(2012. 1. 3), "PMO was introduced from 1950s in the USA and as of 2010, PMO participated in 84% of project ordered by public and private sector." And Ministry of public administration and security announced that the Ministry will organize Task Force for arranging "standard for introduction and operation of PMO" for support of project implementation and strengthening specialty of ordering organization, and then, actively launch the Task Force from February, 2012. Thus, necessity of PMO is regarded as natural in some aspect but thesis for doctoral degree written by Kim Gi-yeong(2007) suggested, "performance of several projects begun at the same time cannot be interpreted as high according to whether PMO team exists or not." Martin et al.(2005) asserted, "according to whether PMO team exists or not, but there is no significant difference in other factor." In the contradictory situation, it is necessary to perform more various approaches for performance and necessity of PMO in the academic aspect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6282-6289
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• 2015

Today, there is an increasing number of cases in which certificate information is leak, and accordingly, electronic finance frauds are prevailing. As certificate and private key a file-based medium, are easily accessible and duplicated, they are vulnerable to information leaking crimes by cyber-attack using malignant codes such as pharming, phishing and smishing. Therefore, the use of security token and storage toke' has been encouraged as they are much safer medium, but the actual users are only minimal due to the reasons such as the risk of loss, high costs and so on. This thesis, in an effort to solve above-mentioned problems and to complement the shortcomings, proposes a system in which digital signature for Internet banking can be made with a simply bio-authentication process. In conclusion, it was found that the newly proposed system showed a better capability in handling financial transitions in terms of safety and convenience.