• Journal of The Korean Astronomical Society
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• v.47 no.6
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• pp.255-258
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• 2014

Using sunspot number data from 270 historical stations for the period 1981-2013, we investigate their personal reduction coefficients (k) statistically. Chang & Oh (2012) perform a simulation showing that the k varies with the solar cycle. We try to verify their results using observational data. For this, a weighted mean and weighted standard deviation of monthly sunspot number are used to estimate the error from observed data. We find that the observed error (noise) is much smaller than that used in the simulation. Thus no distinct k-variation with the solar cycle is observed contrary to the simulation. In addition, the probability distribution of k is determined to be non-Gaussian with a fat-tail on the right side. This result implies that the relative sunspot number after 1981 might be overestimated since the mean value of k is less than that of the Gaussian distribution.

• Wind and Structures
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• v.11 no.1
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• pp.19-33
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• 2008

This research investigates the adaptive input estimation method applied to the multilayer shearing stress structure. This method is to estimate the values of wind load inputs by analyzing the active reaction of the system. The Kalman filter without the input term and the adaptive weighted recursive least square estimator are two main portions of this method. The innovation vector can be produced by the Kalman filter, and be applied to the adaptive weighted recursive least square estimator to estimate the wind load input over time. This combined method can effectively estimate the wind loads to the structure system to enhance the reliability of the system active performance analysis. The forms of the simulated inputs (loads) in this paper include the periodic sinusoidal wave, the decaying exponent, the random combination of the sinusoidal wave and the decaying exponent, etc. The active reaction computed plus the simulation error is regard as the simulated measurement and is applied to the input estimation algorithm to implement the numerical simulation of the inverse input estimation process. The availability and the precision of the input estimation method proposed in this research can be verified by comparing the actual value and the one obtained by numerical simulation.

• Journal of Korean Academy of Nursing
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• v.50 no.6
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• pp.787-798
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• 2020

Purpose: This study aimed to assign weights for subscales and items of the Post-Intensive Care Syndrome questionnaire and suggest optimal cut-off values for screening unplanned hospital readmissions of critical care survivors. Methods: Seventeen experts participated in an analytic hierarchy process for weight assignment. Participants for cut-off analysis were 240 survivors who had been admitted to intensive care units for more than 48 hours in three cities in Korea. We assessed participants using the 18-item Post-Intensive Care Syndrome questionnaire, generated receiver operating characteristic curves, and analysed cut-off values for unplanned readmission based on sensitivity, specificity, and positive likelihood ratios. Results: Cognitive, physical, and mental subscale weights were 1.13, 0.95, and 0.92, respectively. Incidence of unplanned readmission was 25.4%. Optimal cut-off values were 23.00 for raw scores and 23.73 for weighted scores (total score 54.00), with an area of under the curve (AUC) of .933 and .929, respectively. There was no significant difference in accuracy for original and weighted scores. Conclusion: The optimal cut-off value accuracy is excellent for screening of unplanned readmissions. We recommend that nurses use the Post-Intensive Care Syndrome Questionnaire to screen for readmission risk or evaluating relevant interventions for critical care survivors.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.6
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• pp.96-108
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• 2003

Agricultural water occupies the largest portion of total water use in Korea, and generally researches on the development of agricultural water have been stressed on the demand of agricultural water itself. But it is unavoidable to change a policy from the development of water resources to cope with the increase of water demand to the effective management of existing water resources. Evaluation of the decrepitude of irrigation facilities and their reasonable maintenance are important for the effective supply and use of agricultural water. Therefore it is necessary to develop evaluation technique that diagnoses the current condition of irrigation canals and suggest a countermeasure to improve the found problems. 25 items in 6 classes were selected for the evaluation of irrigation canal systems, and the weighted value between the items was calculated using AHP (Analysis Hierarchy Process) method. The current condition of the irrigation facilities was evaluated from the class evaluation marks, and ranking was decided from the total marks between the projects, and finally the priority of the project for the improvement was given.

• Steel and Composite Structures
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• v.11 no.2
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• pp.115-130
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• 2011

Considering the randomness of material parameters in the laminated composite plate, a scheme of stochastic finite element method to analyze the displacement response variability is suggested. In the formulation we adopted the concept of the weighted integral where the random variable is defined as integration of stochastic field function multiplied by a deterministic function over a finite element. In general the elastic modulus of composite materials has distinct value along an individual axis. Accordingly, we need to assume 5 material parameters as random. The correlations between these random parameters are modeled by means of correlation functions, and the degree of correlation is defined in terms of correlation coefficients. For the verification of the proposed scheme, we employ an independent analysis of Monte Carlo simulation with which statistical results can be obtained. Comparison is made between the proposed scheme and Monte Carlo simulation.

• Korean Institute of Interior Design Journal
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• v.24 no.2
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• pp.108-116
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• 2015

The probability of visual perception occurrence varies in case the expectation of using each unit space of which the whole space consists because the size of space subject to analysis is very large or the organization is complicated in the analysis of spatial visual configuration. Therefore, it is necessary to compensate space analysis and index measurement by applying weight to the point of view for the probability of experiencing space. This study proposed a method of analyzing visibility ratio by applying the integration of space syntax theory as weight, and grasped the effect in comparison with the visibility ratio when weight was not applied.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.2
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• pp.362-372
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• 1996

Recently, need for the development of the quantification of subjective evaluation is growing for the production of high-touch and high-tech textile products. In this study, Fuzzy theory is utilized for the evaluation of the wear comfort of the various blouses. Result of a new evaluation method and factor scores, validity of the new evalution technique adopted fuzzy theory was crosschecked with the results of fator analysis and factor scores. As results, fuzzy theory was proved to be adequate methodology to objectify the subjective evaluation of the adequacy of clothing which is worn. When DUNCAN'S multiple comparion among median of the fuzzy composite score were compared with the results of factor score, the sensitivity of the test methods tends to increase. Therefore, it is suggested that fuzzy weighted checklist is an alternative evaluation scale for the subjective comparison of the textile products. In addition, individual median of fuzzy composite score value should be treated by statistical for the sensitive analysis of subjective evalution.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.11-18
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• 1998

In this paper the stochastic analysis of semi-infinite domain is presented using the weighted integral method, which is expanded to include the infinite finite elements. The semi-infinite domain can be thought as to have more uncertainties than the ordinary finite domain in material constants, which shows the needs of and the importance of the stochastic finite element analysis. The Bettess's infinite element is adopted with the theoretical decomposition of the strain matrix to calculate the deviatoric stiffness of the semi-infinite domains. The calculated value of mean and the covariance of the displacement are revealed to be larger than those given by the finite domain assumptions giving the rational results which should be considered in the design of structures on semi-infinite domains.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.609-619
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• 2017

A Manufacturing Readiness Assessment (MRA) was adapted to prevent the probable ascending expense, poor quality, and delay from the development to production phase and assess the level of manufacturing readiness in 2012. Consequently, there are positive effects on improving the quality to identify the manufacturing risks during the production of military supplies and manage the issues in advance. On the other hand, because the appraisee is becoming accustomed to preparing for MRA checklists tailoring, it was found to intensify the MRA points more than before, which damages the goal of the MRA. This paper proposes the quantitative MRA methodology using MWV (Manufacturing Readiness Level 8 Weighted Value) to define and measure the HOM8, DOM8, ICOM8, and M8RA to reflect the history of MRA, the difficulties of MRA checklists, the intrinsic cruciallity and risk assessment of program, which can overcome the problems mentioned before. This paper shows the MWV of four weapon system programs to be carried out and an analysis of the proposed MRL 8 methodology.

• Journal of the Korean GEO-environmental Society
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• v.21 no.5
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• pp.5-11
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• 2020

Outliers detection and elimination included in field monitoring datum are essential for effective foundation of unusual movement, long and short range forecast of stability and future behavior to various structures. Integrated outlier analysis system for assessing long term time series data was developed in this study. Outlier analysis could be conducted in two step of primary analysis targeted at single dataset and second multi datasets analysis using synthesis value. Integrated outlier analysis system presents basic information for evaluating stability and predicting movement of structure combined with real-time safety management platform. Field application results showed increased correlation between synthesis value including similar sort of sensor showing constant trend and each single dataset. Various monitoring data in case of showing different trend can be used to analyse outlier through correlation-weighted value.