• Journal of the Korean Society of Radiology
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• v.5 no.5
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• pp.223-229
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• 2011

When negative electron in x-ray tube is accelerated in to a high speed and then the currency of the electron is blocked by the target, x-ray happens by the conversion of the energy. The real area where the fast accelerated electron collides to a target area is called actual focal spot. When the string focused size is observed at the central ray side, where the direction x-ray comes out, the size seems to be reduced. This focus is called effective focal spot. According to radiation angle of x-rays tube, the degree of the negative pole side presents higher value than inclination, the amount of exposed radiation that patient receives differs by the angle of positive pole, which means effective focal spot is the variable. This paper presents the correlation between size of effective focal spot and amount of exposed radiation to the patient by it, and effective research for homogenized dose dispersion by the size of effective focal spot. In conclusion, following the focal size, effective range which was -8cm ~ 0 cm on average, was found and average dose rate was 0.019 R/min. Through this range, for patients with small radiation exposure, image with good density and resolution in aspect of diagnosing will be able to be obtained.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.4
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• pp.109-121
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• 2003

The point of this research is the use of the high resolution satellite image for local government's new address system, as well as spatially field investigation support and base map error finding. Most local governments use scale 1/1,000 and 1/5,000 digital map for base map and field investigation. But field investigator's knowledge insufficiency and the lack of base map's currency make things too difficult from the beginning of the project. As the way of solving this problem, this research offers the use of the high resolution satellite image in new address system with cadence data of digital base map. Until now satellite image is not suitable for our situation because it has low resolution. But this problem was solved for 1m space resolution satellite image and it is being applied wider and wider. Now vector data and Raster data are integrated for complimenting of each weak point. In this study the use of the high resolution satellite image in new address system is expected to improve the quality of the results and reduce the expenses. In addition the satellite image can use local government's fundamental data.

• Journal of Korea Multimedia Society
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• v.16 no.8
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• pp.982-993
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• 2013

Currency crisis, in order to solve the problem of the polarization of economic and serious youth unemployment rate, to prepare for the smart new economic era, and like to support and nurture the one-persion creating company of mobile app industry of central and local government people policies are underway. To be able to contribute to the establishment of the success of mobile app One-person creating company, to target the mobile app One-person creating company int the Busan region, we conducted an empirical study of success factors, and thus, support these solutions, more effective and efficient in an attempt to try to seek the support measures, was carried out this research. In this study, results derive a research three hypotheses about the success factors of One-person creating company through literature discussion, were investigated on the basis of empirical data of the mobile app one-persion creative company of Busan region of 51 individual, establishment of company period is longer, the number of organizations employee is large and attract a lot of external funds, and was able to find the tendency of more entrepreneurs receives an education, may increase an outcome of business. In this study, it is possible to obtain the policy implications as follows. First, to attract investment funds and attract government funding to support the funding of One-person creating company, it is necessary to pay attention more. Second, policy founder to an education about the management on an ongoing basis is needed than the education of marketing and technology for human resources development. Future, you will be able to expand across the country study company, we have established a policy of mobile app industry of national dimension, in this foundation, will be expanded to all industries.

• KDI Journal of Economic Policy
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• v.27 no.1
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• pp.1-38
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• 2005

Our paper aims to estimate a household consumption function in the presence of liquidity constraints as well as household characteristics. Empirical findings from a Korean cross-sectional data (National Survey of Household Income and Expenditure) reveal that several family characteristics, such as household size, number of working members, children in school, and educational level and age of the household head, turn out to be critical determinants of household consumption. Especially, the influence of household size on consumption decision is shown to be highly significant, not only indirectly through its impact on household income, but also directly by affecting the household's preference for consumption itself. While, the other family characteristics primarily influences household income. Our paper distinguishes itself from existing literature in that it greatly improves the explanatory power of the estimated household consumption function by measuring the degree of the liquidity constraint rather than simply identifying its presence. Based on the assumption that the present value of human capital is a function of household characteristics, the degree of the liquidity constraint is represented by the underestimated portion of the human capital. Such a method of implementing the liquidity constraint is useful in treating various types of assets according to their liquidity. Finally, our estimated household consumption function is applied to decompose cross-sectional variances of consumption inequality. The analysis confirms that the overall alleviation in liquidity constraints in Korea after the 1997 currency crisis reduced consumption inequality despite the worsening of income inequality and changes in the demographic composition of family characteristics during the same period.

• KDI Journal of Economic Policy
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• v.27 no.1
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• pp.185-209
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• 2005

This study examines ERPT with asymmetric response and both import and export market shares, using wool trade data. The study found that, asymmetric response may be as common as symmetric response. In addition, the responses (both in price and quantity demanded) to the changes in exchange rate are considerably different across goods, and even for the homogenous goods, across countries. In case of depreciation, the export price changes more than appreciation case in general, and as a result the destination price changes less. It is also found that the cases of excessive or perverse pass-through are found more frequently than reported by previous studies. This finding points out that strategic behavior of firms or unexpected response to exchange rate fluctuation takes place more frequently than we commonly expect or take, in particular at disaggregated levels. When the model considers asymmetric responses of the export price to appreciation and depreciation (of exporter's currency), the estimation provided that for 39 trade cases out of 83, export price responded to appreciation and depreciation in different fashions, although the normal response was the dominating phenomenon with 99 cases or about 60% out of 166 cases. Market shares affected the extent and direction of responses in select cases. These findings will have important implications for policy makers and traders.

• Journal of Information Management
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• v.33 no.1
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• pp.31-47
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• 2002

The main purpose of this research is to look into not only how users evaluate two major databases(BIST and SATURN) of the scientific and technical literature in Korea, but also what users expect from scientific and technical information services in general. The result of the user evaluation shows that there is a very little difference between two databases in database quality. It was found that BIST is better than SATURN in terms of accuracy, customer support, searching capability, and currency, whereas SATURN is preferred to BIST for completeness and the average number of retrieved items. User expectation for scientific and technical information is also investigated by surveying its user community. Among three user groups, there is notable disagreement in language uses to search non-korean literature. Each group also shows different demands for translation of original literature. This study attempted to evaluate the quality of the scientific and technical information (BIST and SATURN) and simultaneously to investigate users demands in general. By doing so, the specificity implied in quality evaluation of specific information services as well as the generalization of the users behaviors in scientific and technical community were accommodated in this study.

• Proceedings of the Korea Database Society Conference
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• 1999.06a
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• pp.175-186
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• 1999

Detecting the features of significant patterns from their own historical data is so much crucial to good performance specially in time-series forecasting. Recently, a new data filtering method (or multi-scale decomposition) such as wavelet analysis is considered more useful for handling the time-series that contain strong quasi-cyclical components than other methods. The reason is that wavelet analysis theoretically makes much better local information according to different time intervals from the filtered data. Wavelets can process information effectively at different scales. This implies inherent support fer multiresolution analysis, which correlates with time series that exhibit self-similar behavior across different time scales. The specific local properties of wavelets can for example be particularly useful to describe signals with sharp spiky, discontinuous or fractal structure in financial markets based on chaos theory and also allows the removal of noise-dependent high frequencies, while conserving the signal bearing high frequency terms of the signal. To date, the existing studies related to wavelet analysis are increasingly being applied to many different fields. In this study, we focus on several wavelet thresholding criteria or techniques to support multi-signal decomposition methods for financial time series forecasting and apply to forecast Korean Won / U.S. Dollar currency market as a case study. One of the most important problems that has to be solved with the application of the filtering is the correct choice of the filter types and the filter parameters. If the threshold is too small or too large then the wavelet shrinkage estimator will tend to overfit or underfit the data. It is often selected arbitrarily or by adopting a certain theoretical or statistical criteria. Recently, new and versatile techniques have been introduced related to that problem. Our study is to analyze thresholding or filtering methods based on wavelet analysis that use multi-signal decomposition algorithms within the neural network architectures specially in complex financial markets. Secondly, through the comparison with different filtering techniques' results we introduce the present different filtering criteria of wavelet analysis to support the neural network learning optimization and analyze the critical issues related to the optimal filter design problems in wavelet analysis. That is, those issues include finding the optimal filter parameter to extract significant input features for the forecasting model. Finally, from existing theory or experimental viewpoint concerning the criteria of wavelets thresholding parameters we propose the design of the optimal wavelet for representing a given signal useful in forecasting models, specially a well known neural network models.

• Korean journal of communication and information
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• v.78
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• pp.177-205
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• 2016

This study set out to investigate the reality of local press and changes to the occupational identity of reporters through the job mobility of reporters at local newspapers. The study examined what reasons the reporters had when they retired from one of three paper newspapers in Daejeon, where they moved to, and how their career mobility was. Some of them remained in the field of journalism including paper newspapers of the same kind and Internet newspapers, and others moved to various areas including politics, administration, academy, economy, and culture and art. The biggest number of them said they left their old paper newspapers because of poor wages and welfare benefits and absence of future visions. Their decision of leaving their old paper newspapers was also influenced by restructuring, restrictions to coverage and reporting, and great workload. Before the IMF foreign currency crisis in 1997, the press labor market was a typical internal labor market with the practitioners joining a newspaper in open recruitment and climbing up the promotion ladder from a common reporter through Deputy Head and Head of a department to Director of a bureau. The emergence of new media and the financial difficulties of newspaper corporations were currently making the internal labor market worse. Reporters made active use of social capital such as regionalism, alumni ties, and news beats rather than changing jobs by increasing their professionalism through self-development, thus causing side effects including the weakened supervision and criticism functions of local newspapers and damaging their occupational identity as reporters.

• Journal of Digital Convergence
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• v.13 no.12
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• pp.151-160
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• 2015

As a lexical meaning, casino is defined as "a certified gambling house, equipped with recreational facilities such as dance and music, etc., where people play roulette or cards." Casinos started from 17th to 18th century for European nobility and their social meetings and established a casino industry framework in the United States in the 1930s. The success of the casino business leads to the increase of sales; it became very helpful for the local and national government revenues and also for the related incidental tasks. Casino operations include a variety of fields, such as general customer management, dealer game management, security, account management, currency exchange, re-exchange management, marketing management, comp management and placement management, etc. These operations should be organically connected to each other by information systems such as a groupware, ERP and Customer Relationship Management (CRM), etc. In addition, in order to effectively manage comprehensive entertainment service, including accommodation and tourism, it is necessary to develop an information system which supports casino business and collateral entertainment service, collects the data generated throughout the business and provides information about the situations of management. Thus, this study will propose a casino information system designed and implemented, considering these details.

• Journal of the Korean Society for Library and Information Science
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• v.46 no.2
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• pp.29-54
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• 2012

This study aims to grasp what factors affect users' recognition level and expectation level for library service, being offered at the library of Korea National Open University. Also, this study seeks to conduct a survey and analyze whether users' recognition level by library service dimensions has actually influenced the intention and the satisfaction with using the library. For this, it carried out the theoretical approach, which considers domestic and foreign documents on evaluation of quality of library service, and the empirical approach of questionnaire research and analysis. A research model was designed on the basis of LibQUAL+model to achieve the objective of this research. And the group-based difference was confirmed by carrying out verification on research hypothesis. As a result of analysis, the users' current recognition level by library service dimensions of Korea National Open University was indicated to have influence on the whole satisfaction with library and the continuous use intention. The whole satisfaction was indicated to have an effect on continuous use intention. Also, to enhance users' satisfaction level according to the behavioral characteristics of using library, the core elements for improving the library service of Korea National Open University were cited and these include improving the facility of library, implementing smart digital library system for offering remotely academic information, and securing diversity and currency of academic information sources such as printing materials and electronic materials.