• 한국경영과학회지
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• 제30권4호
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• pp.15-25
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• 2005

As implied by the terms of IT productivity Paradox, measuring the Information technology contribution to economic performance has been one of the challenging issues to both policy makers and business professionals. As such, diverse attempts with sophisticate analyses have been reported in the literature to analyze the effect of IT contributions. In this paper, we follow Growth Accounting Method to measure the IT contribution effect to manufacturing firm's economic performance in Korea. Various regression methods and statistical analyses are applied with fourteen years of industry Panel data. Using the Cobb-Douglas function, time lag analysis is made to understand IT effect to economic growth. Instead of capturing data from individual firm, industry level data from the National Statistics Bureau is used for IT capital, non-IT capital, and so on. Statistical analysis following the panel unit test and Panel co-integration test was performed to reveal the exact effect of IT contribution to economic performance. Empirical testing results for non-stationary nature of IT investment effect are reported as well as IT contribution to manufacturing industry's economic performance.

• 한국경영과학회지
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• 제29권2호
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• pp.45-57
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• 2004

The purpose of this paper is studying the valuation of option prices in Incomplete markets. A market is said to be incomplete if the given traded assets are insufficient to hedge a contingent claim. This situation occurs, for example, when the underlying stock process follows jump-diffusion processes. Due to the jump part, it is impossible to construct a hedging portfolio with stocks and riskless assets. Contrary to the case of a complete market in which only one equivalent martingale measure exists, there are infinite numbers of equivalent martingale measures in an incomplete market. Our research here is focusing on risk minimizing hedging strategy and its associated minimal martingale measure under the jump-diffusion processes. Based on this risk minimizing hedging strategy, we characterize the dynamics of a risky asset and derive the valuation formula for an option price. The main contribution of this paper is to obtain an analytical formula for a European option price under the jump-diffusion processes using the minimal martingale measure.

• Korean Journal of Radiology
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• 제23권10호
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• pp.986-997
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• 2022

Objective: Whether metabolic redistribution occurs in patients with white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) is unknown. This study aimed 1) to propose a measure of the brain metabolic network for an individual patient and preliminarily apply it to identify impaired metabolic networks in patients with WMHs, and 2) to explore the clinical and imaging features of metabolic redistribution in patients with WMHs. Materials and Methods: This study included 50 patients with WMHs and 70 healthy controls (HCs) who underwent ¹⁸F-fluorodeoxyglucose-positron emission tomography/MRI. Various global property parameters according to graph theory and an individual parameter of brain metabolic network called "individual contribution index" were obtained. Parameter values were compared between the WMH and HC groups. The performance of the parameters in discriminating between the two groups was assessed using the area under the receiver operating characteristic curve (AUC). The correlation between the individual contribution index and Fazekas score was assessed, and the interaction between age and individual contribution index was determined. A generalized linear model was fitted with the individual contribution index as the dependent variable and the mean standardized uptake value (SUV_mean) of nodes in the whole-brain network or seven classic functional networks as independent variables to determine their association. Results: The means ± standard deviations of the individual contribution index were (0.697 ± 10.9) × 10^-3 and (0.0967 ± 0.0545) × 10^-3 in the WMH and HC groups, respectively (p < 0.001). The AUC of the individual contribution index was 0.864 (95% confidence interval, 0.785-0.943). A positive correlation was identified between the individual contribution index and the Fazekas scores in patients with WMHs (r = 0.57, p < 0.001). Age and individual contribution index demonstrated a significant interaction effect on the Fazekas score. A significant direct association was observed between the individual contribution index and the SUV_mean of the limbic network (p < 0.001). Conclusion: The individual contribution index may demonstrate the redistribution of the brain metabolic network in patients with WMHs.

• 대한가정학회지
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• 제36권4호
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• pp.35-48
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• 1998

The imputation of monetary value of women's contribution to the informal economy for inclusion in satellite accounts to the formal System of National Accounts has been attempted along many methods. This is bases on official laborforce statistics and time-use survey. In this statistical system, household work is not an economic activity(or productive labor). Also, the clssification of activities involved in household work is different from that of sampling survey relating evaluation. The measurement of women's unpaid work is one of the important tasks for the improvement of women's status and the establishment of a development policy. To measure unpaid work in the economic terms, we should take following measures; 1) develop satellite or other official accouts to measure unpaid work outside national accounts. 2) conduct a nation-wide time-use survey to measure the unpaid work. 3) develp a proper classificaition of activities for time-use statistics. 4) reexamine the minimum time criterion. 5) determine a proper method of valuing along the law system.

• 원예과학기술지
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• 제16권3호
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• pp.352-354
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• 1998

정밀 양액제어를 위하여 양액재배시스템 및 고정도의 양액의 계측/제어가 가능한 시스템을 제작하였고, EC 제어하에서 양액중의 각 이온이 EC에 기여하는 비율을 추정하였다. 양액재배시스템에 별도의 측정조를 사용하여 센서의 세척 및 측정이 가능하도록 설계하였고, 1대의 본체로 복수의 양액재배 시스템의 정밀 계측이 가능하였다. 또한 정량조를 이용한 Overflow 방식의 양액공급장치에 의하여 양액제어 결과, $EC{\pm}0.05mS/cm$, $pH{\pm}0.05$ 이하의 범위에서 양액의 정밀 제어가 가능하였다. EC 제어상태에서 양액중의 2가이온의 증가와 활동도계수의 감소가 나타났고, 활동도계수와 당량이온전 도도를 이용한 양액중의 각 이온의 EC기여도의 변화 내용이 확인되었다.

• The Korean Journal of Ceramics
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• 제7권1호
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• pp.30-35
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• 2001

The contribution of the non-$180^{\circ}C$ domains to the electric-field-induced strains (EFI-strains) of PZT ceramics was evaluated by an XRD method and by an interferometric method. The XRD intensity ratio of 200 and 002 diffraction peaks of tetragonal PZT was measured under strong electric fields. The amount of the $90^{\circ}$ domain reorientation was evaluated and the strain due to the domain reorientation was calculated. It was confirmed that the EFI-strain of PZT ceramics was equal to the sum of the strain calculated from the d$_33$ constant determined by the resonance-antiresonance method and the strain due to the $90^{\circ}$ domain reorientation. The amount of the $90^{\circ}$domain reorientation has a linear relation with the c/a ratio in the "soft" PZT ceramics. A Mech-Zehnder interferometer was constructed to measure the EFI-strains vs. electric-field curves of PZT ceramics as a function of frequency. The EFI-strain vs. electric-field curve showed a hysteresis due to the effect of the non-$180^{\circ}$ domain reorientation when the applied voltage was high and its frequency was low. The apparent piezoelectric constant increased from the d$_33$ value determined by the resonance-antiresonance method with decreasing frequency. This deviation was attributed to the non-$180^{\circ}$ domain contribution.tribution.

• 기술혁신학회지
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• 제7권3호
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• pp.657-679
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• 2004

The purpose of this paper is to measure economic impact of marine environment conservation research development project. Benefit-Cost(B/C) analysis and Contingent Valuation Methods(CVM) are used to valuate the benefits from the research development projects. A period of three years for research development fund is considered as a part of the costs and adjusted to the net present value (NPV) of the 2002 ending period. The environmental charges for marine environment improvement are considered for the benefit measurement. The benefits are estimated by using monthly average willingness to pay, which is 2,289 Korean won. The contribution of the developing a management model for environmental pollution in the Gwangyang Bay is evaluated utilizing survey data and information. Based on the assessment by expert groups, the contribution of the model was 37.5％. The research results showed that B/C ratio is 20.61, NPV is 89,200 million Korean won, and social rate of return is 185.7％. When the level of contribution is over 1.83％ at the assessment of potential influence, it is recognized to be economically feasible. This research presents a quantitative framework for Research and Development projects for marine environment conservation, and it can be applied to decision making for the investment size of R&D projects.

• 부모자녀건강학회지
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• 제17권1호
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• pp.29-36
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• 2014

Purpose: Competence in parenting helps the parent to recognize the ability to resolve problems arising to children, allowing positive interactions with children through desirable child-rasing behavior and smooth communication with children. This study aims to identify the contribution of uncertainty and educational needs to the competence in parenting. Methods: Total 159 mothers responded a questionnaire developed to measure uncertainty, educational needs, and competence in parenting. t-test, ANOVA, and stepwise multiple regression with the SPSS program were used to analyze the data. Results: We found that uncertainty, nursing educational need, and mothers' age had influence to the competence in parenting. Conclusion: Nursing interventions provided to the mothers of hospitalized children for better parental competence need to include programs for alleviating uncertainty and satisfying the need for nursing education.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2011년도 학술발표회
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• pp.188-193
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• 2011

This study was intended to estimate the soil runoff at the basin of Mandaechun where the measure needs to be taken to deal with the increasing muddy water resulting from soil runoff during wet season and torrential rain at the high reaches of the Soyang lake where highland vegetables are cultivated and soil replacement for improvement is carried out every two to three years. The study was carried out in such a way of identifying the topographic factors using geographical spatial data from Water Management Information System (WAMIS) and ARC-VIEW program and estimating the soil runoff by rainfall frequency using Revised Universal Soil Loss Equation (RUSLE), and furthermore, evaluating the soil runoff contribution at the basin of Mandaechun based on estimate of the soil runoff by section.

• 한국IT서비스학회지
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• 제12권2호
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• pp.119-129
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• 2013

The degree to which people share knowledge has major impacts on the effectiveness of virtual community of practice (VCoP). As an extension to the previous study which investigated the effect of individual cooperative types (cooperator, reciprocator, and free rider) on knowledge sharing, it is investigated how much increase in the degree of cooperation will enhance knowledge sharing when there are more knowledge contributors and strong ties exist across the community. Simulation method is adopted to measure the effect of the cooperative type and tie strength on knowledge sharing. The results reveal that the tie strength positively affects knowledge contribution in VCoP and strongly tied VCoP generates equivalent level of knowledge contribution as that of weakly-tied VCoP with 5% more contributors.