• The KIPS Transactions:PartB
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• v.13B no.3 s.106
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• pp.329-336
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• 2006

In this paper, we propose a method of significant term extraction within a document. The technique used is Principal Component Analysis(PCA) which is one of the multivariate analysis methods. PCA can sufficiently use term-term relationships within a document by term-term correlations. We use a correlation matrix instead of a covariance matrix between terms for performing PCA. We also try to find out thresholds of both the number of components to be selected and correlation coefficients between selected components and terms. The experimental results on 283 Korean newspaper articles show that the condition of the first six components with correlation coefficients of |0.4| is the best for extracting sentence based on the significant selected terms.

• Journal of KIISE
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• v.45 no.1
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• pp.76-85
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• 2018

Governments and public agencies try to use the cloud to carry out their work and provide public services. However, a public cloud is vulnerable to security side because it has a structure to support services using public networks (i.e, the internet). Thus, this paper finds the general security vulnerabilities of a network and compares and analyzes the characteristics of transport protocols (UDP, TCP, SCTP, and MPTCP) on the basis of their security vulnerabilities. This paper uses a reliability and security factor for the comparative analysis, evaluates the security exposure, and chooses a suitable protocol considering the security of the transport protocols in the cloud circumstance.

• International Journal of Contents
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• v.5 no.4
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• pp.13-18
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• 2009

The existence of Korean schools is one of the salient characteristics of Overseas Koreans. How do such schools for Korean immigrants' children try to construct Korean ethnic identity? Also, how is immigrant children's ethnic identity developed and reinforced by the education at those schools? This paper explores these questions based on an ethnographic research at a Korean school in Paris from September 2005 to December 2007. The cultural education for immigrant children at the Korean school has a tendency to emphasize the most exotic traits of Korean culture. And this emphasis on the unfamiliar elements of Korean culture doesn't seem to help to form the ethnic identity of Korean immigrants' children. Instead, the students appear to get the sense of being a member of Koreans more from the education outside of classroom such as scholastic events than in a classroom of a Korean school. That's because scholastic events allow them to play out some of the Korean culture in more inter-ethnic settings. Therefore, it can be concluded that ethnicity of immigrant children is rather developed in inter-ethnic social contexts than born with or taught in class.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.4
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• pp.76-84
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• 2008

In this study, we try to select the sites and set the boundary in the Improvement Promotion Project as a case analysis of Busan Metropolitan City Area. Specifically speaking, we build the database of the city improvement promotion project area, spread out collectively in the Busan City, select the possible sites recommended by the basic units of local government, and analyse these sites through applying our physical standards. The result is as follows ; The degree of advancement and driving willpower from the basic units of local government are largely effective on the improvement project, but in terms of accessibility, decrepitude, and development density, there are relatively negligible differences among the possible sites.

• Proceedings of the Korean System Dynamics Society
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• 2007.11a
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• pp.49-65
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• 2007

Nowadays almost nations try to promote the competition of nation through the development of national science technology. Also Korea has been engaging in this race of through public research & development institute. But recently the commercialization of R&D products appears a poor result in the royalty of technology according weak technology transfer toward IT small and medium-sized enterprises. Even If we have been trying to find the problems and causes, as yet it is true that we don't solve clearly the problem, make a diagnosis about it. This paper analyzes the process of commercialization in public R&D research institute(ETRI: Electronics and Telecommunications Research Institute) through system thinking and researches an interrelationship among government agency, public R&D research institute, and enterprise. This one can find the fact that between research fund and R&D products, transfer technology and royalty, and enterprise's operating profit and active technology transfer like adding technology development is a positive feedback loop. This positive feedback loop in the commercialization of public R&D research institute carries out very important role in examining problems in R&D product's commercialization. Also this paper looks forward to being a guide in the commercialization of public R&D research institute.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4644-4661
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• 2015

Wireless sensor networks are often organized in the form of clusters leading to the new framework of WSN called cluster or hierarchical WSN where each cluster head is responsible for its own cluster and its members. These hierarchical WSN are prone to various routing layer attacks such as Black hole, Gray hole, Sybil, Wormhole, Flooding etc. These routing layer attacks try to spoof, falsify or drop the packets during the packet routing process. They may even flood the network with unwanted data packets. If one cluster head is captured and made malicious, the entire cluster member nodes beneath the cluster get affected. On the other hand if the cluster member nodes are malicious, due to the broadcast wireless communication between all the source nodes it can disrupt the entire cluster functions. Thereby a scheme which can detect both the malicious cluster member and cluster head is the current need. Abnormal energy consumption of nodes is used to identify the malicious activity. To serve this purpose a learning based energy prediction algorithm is proposed. Thus a two level energy prediction based intrusion detection scheme to detect the malicious cluster head and cluster member is proposed and simulations were carried out using NS2-Mannasim framework. Simulation results achieved good detection ratio and less false positive.

• Journal of Korean Society for Quality Management
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• v.26 no.2
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• pp.93-105
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• 1998

Many large scale discount stores try to enter the market in newly developed city areas. In order to sucessfully increase the market share, it is essential for them to understand customers' needs. In doing so, various forms of survey methods are often used and survey forms can influence respondents' decision. The main objective of this paper is to check consistency of different survey methods in terms of deriving the expected market share. In this paper, we a, pp.y two survey forms for both AHP and conjoint analyses using a randomized complete block design. Using AHP, we compare Kim's club, Carf, E-mart and Macro in terms of the following four customer attributes: parking facility, size of store, business hours, and special pricing policy. In conjoint analysis, we estimate the part-worth of each level of the customer's attribute so that one can design the best store which would optimizethe customer's attribute so that one can design the best store which would optimize the customer's utility. Empirical comparison results indicate very low consistency between the two methods. It implies the importance of verification methods of survey. We also analyze the impact of special pricing policy using a meta analysis. It turns out that older customers are a, pp.rently more sensitive to pricing policy.

• Journal of Korean Society of Rural Planning
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• v.19 no.1
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• pp.55-70
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• 2013

Since 2004, Ministry for Food, Agriculture, Forestry and Fisheries(MIFAFF) has been carrying out comprehensive rural village development project as the core one of Rural Area Development Schemes in Korea. Up to now, 56 projects had been completed after having with 5-year plan implementation period, on which it is possible to try post-project evaluation works. This study aims to propose a rational income-generation works model of comprehensive rural village development project, based on fulfillment checking results of their statutory stepwise working procedures specified in the project guidelines and their interim/post project performance analysis results in 56 project areas above mentioned. In comprehensive rural village development project, income-generation works generally have both quantitative and qualitative effects to rural communities; the former is focussed on income increasement of villagers, while the latter on community revitalization through job creation and spill-over effects of other linked community activities. So, the research works of this study focussed on these two comprehensive effects above mentioned.

• Transactions of Materials Processing
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• v.22 no.6
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• pp.317-322
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• 2013

A radio frequency(R/F) switch connector is widely used in wireless devices such as mobile phone and navigator to check defects of the circuit board of product. The R/F switch connector shell plays a role in protecting the switch connector. Previously, this part was machined using a turning, which is time-consuming and has poor material utilization. Furthermore, the workpiece material of brass containing lead that has excellent machinability has environmentally regulated during recent years. The purpose of the current study was to develop the connector shell by forming through progressive dies including embossing, burring and forging process in order to achieve higher productivity and dimensional accuracy without tool failure. To accomplish this objective, a strip layout was designed and finite element (FE) analysis was performed for each step in the process. Try-out for the connector shell was conducted using progressive die design based on FE-analysis results. Dimensional accuracy of developed part was investigated by scanning electron microscopy. The result of the investigation for the dimensions of the formed connector shell showed that the required dimensional accuracy was satisfied. Moreover, productivity using the progressive die increased four times compared to previous machining process.

• Journal of Welding and Joining
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• v.17 no.6
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• pp.84-89
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• 1999

Most of ferrous b.c.c weld materials may experience martensitic transformation during rapid cooling after welding. It is well known that volume expansion due to the phase transformation could influence on the relaxation of welding residual stress. To apply this effect practically, it is a prerequisite to establish a numerical model which is able to estimate the effect of phase transformation on residual stress relaxation quantitatively. For this purpose, the analysis is carried out in two regions. i.e., heating and cooling, because the variation of material properties following a phase transformation in cooling is different in comparison with the case in heating, even at the same temperature. The variation of material properties following phase transformation is considered by the adjustment of specific heat and thermal expansion coefficient, and the distribution of residual stress in analysis is compared with that of experiment by previous study. consequently, in this study, simplified numerical procedures considering phase transformation, which based on a commercial finite element package was established through comparing with the experimental data of residual stress distribution by other researcher. To consider the phase transformation effect on residual stress relaxation, the transition of mechanical and thermal property such as thermal expansion coefficient and specific heat capacity was found by try and error method in this analysis.