• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.327-330
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• 2007

This paper verifies that the normality assumption that the simulation output data, Project Completion Times (PCTs), follow normal distribution is not always acceptable and the existing belief may lead to misleading results. A risk quantification method, which measures the effect caused by the assumption, relative to the probability distribution of PCTs is implemented as an algorithm in MATLAB. To validate the reliability of the quantification, several series of simulation experiments have been carried out to analyze a set of simulation output data which are obtained from different type of Probability Distribution Function (PDF) assigned to activities'duration in a network. The method facilitates to find the effect of PDF type and its parameters. The procedure necessary for performing the risk quantification method is described in detail along with the findings. This paper contributes to improving the reliability of simulation based scheduling method, as well as increasing the accuracy of analysis results.

• Korean Journal of Remote Sensing
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• v.20 no.6
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• pp.397-408
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• 2004

In this study, surface temperature which was extracted from Landsat TM band 6 was compared and analyzed with the AWS(Automatic Weather System) observation data for studying urban heat environment properties with possibility of remote sensing data application. In order to verification of the distribution properties of urban surface temperature, correlation analysis between surface temperature and NDVI, the distribution properties of urban surface temperature by land use/cover patterns were carried out by GIS spatial analysis techniques. The results presented that the spatial distribution of urban surface temperature was very different depending on various land use/cover patterns of surrounding areas. Also there was the reverse linear relationship between surface temperature and NDVI. These results will be worked as one of the major factors for environmentally sustainable urban planning considering the characteristics of weather environments in the near future.

• Korean Journal of Plant Resources
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• v.12 no.4
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• pp.297-302
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• 1999

This study was carried out to find morphological characters of flower and its distribution in mixed population of Paeonia lactiflora Pallas. In distribution of flowering periods, early, medium, and late matured type were 18%, 56%, and 26%, respectively. Flowering duration was less than eight days in 9% of flowers. In next 9 to 11 days, 12 to 14 days and more than 15 days showed, 50%, 37% and 4% respectively. For flower sizes, small size below 9cm diameter were 11%, medium size between 9 to 13cm diameter and large size above 13cm diameter were 65% and 24%, respectively. Among six kinds of flower colors - red, red pink, pink, light pink, pale yellow and white, pink color flowers was dominant, showed 56%. In flower types, single flower was 76%, and anemone, crown, bomb and japanese types were also present. Flower stem diameter were positively correlated with flowering duration, flower size and number of stamens, and negatively correlated with number of stamens and pistils, number of pistils and petals.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.1
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• pp.17-25
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• 2019

An intake of Aircraft becomes S-shaped geometry due to spatial limitation or procuring survivability. But curvature of the S-shaped geometry makes secondary flow or flow separation which is the cause of non-uniform pressure distribution. In this study, boundary layer suction is applied to RAE M 2129 S-Duct by attaching sub duct. Design variable is suction location and angle. A mass flow rate drawn out by suction at the sub duct outlet is constant over every model. A grid dependency test was conducted to verify validity of computation. The comparison among the CFD (Computation Fluid Dynamics), ARA experimental result, and ARA computation result of non-dimensional pressure distribution on the Port side and Starboard Side confirmed the validity of CFD. In this study, Distortion Coefficient was used for evaluating aerodynamic performance of S-Duct. The analysis, which was about flow separation, vortex, mass flow rate distribution, and pressure distribution were also investigated. Maximum 26.14% reduction in Distortion Coefficient was verified.

• Korean Journal of Clinical Pharmacy
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• v.25 no.4
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• pp.280-285
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• 2015

Objectives: To suggest direction for improving policies by understanding current management of narcotics or psychotropic drugs and analyzing their distributions and usage. Method: We conducted a comparison analysis between health insurance claims and the amount supplied to health care institutions for narcotics or psychotropic drugs through health insurance claims data and drug distribution supply data from 2010 to 2012 collected from Korea Pharmaceutical Information Service Center (KPIS). Furthermore, we carried out literature investigation and online search to comprehend the current management of narcotics drugs in Korea. Results: The amount supplied to medical institutions for all drugs in 2012 was 19.4 trillion won, which increased from 19.5 trillion in 2011 by 0.54%. For narcotic drugs, the amount supplied was 318.4 billion won in 2011 and increased to 335.1 billion won by 5.3% in 2012, which exceeded the rate of increase for the amount supplied for all drugs. The proportion of amount claimed in the total amount supplied to medical institutions for all drugs was 60.5% in 2012, whereas the proportion of amount claimed for narcotic drugs was 55.6%, which showed that narcotic drugs were used relatively less within health insurance. Furthermore, management of the current domestic distribution supply data focuses on manufacturing and medical institution supply stages. Conclusion: Hereafter, the management of narcotics or psychotropic drugs needs to be improved by reinforcing active monitoring in optimal prescription and usage in patients by collecting and analyzing information on drug usage of patients.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.10
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• pp.1281-1289
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• 2011

This paper deals with several statistical distribution functions for the analysis of fatigue life data of composite laminates for small wind-turbine blades. A series of tensile tests was performed on triaxial glass/epoxy laminates for loading directions of $0^{\circ}$, $45^{\circ}$, and $90^{\circ}$. Then, fatigue tests were carried out to determine the fatigue life at the aforementioned loading directions and the fatigue stresses at four levels. Two-parameter Weibull, three-parameter Weibull, normal, and log-normal distributions were used to fit the fatigue life data of the triaxial composite laminates. The three-parameter Weibull distribution most accurately described the fatigue life data measured experimentally for all the cases considered. Furthermore, the variation of fatigue life was simultaneously affected by the loading direction and fatigue stress level.

• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.1-9
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• 2008

In this paper, make a study decision problem called an optimal release policies after testing a software system in development phase and transfer it to the user. When correcting or modifying the software, because of the possibility of introducing new faults when correcting or modifying the software, infinite failure non-homogeneous Poisson process models presented and propose an optimal release policies of the life distribution applied log-logistic distribution which can capture the increasing! decreasing nature of the failure occurrence rate per fault. In this paper, discuss optimal software release policies which minimize a total average software cost of development and maintenance under the constraint of satisfying a software reliability requirement. In a numerical example, after trend test applied and estimated the parameters using maximum likelihood estimation of inter-failure time data, make out estimating software optimal release time.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.562-567
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• 2012

Noises from the large scale marine propeller are calculated numerically on non-cavitation condition. The hydrodynamic analysis are carried out by potential based panel method with time marching free wake approach. The distribution of hyrodynamic loads on the propeller surface and noise signals are obtained using the unsteady Bernoulli's equation and the Farasssat formula respectively. It turns out that the noise signal shows strong peak at the blade passage frequency. Noise signals and directivity patterns for both the thickness and the loading noise are compared with each other. The directivity pattern for the loading noise shows minor lobe at the backward side of the rotating disc plane.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.107-112
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• 2002

In order to investigate the situation of ocular disorders involving visual functions of elder in the Island area, the survey was carried out subjective methods on 228 persons(456 eyes) over the of 60. The analysis of data resulted in as follows : 1. Among the total 456 eyes, the ocular disorders was 54.8%. 2. The causes of ocular disorders with visual impairment ; Senile cataract(44.8%), Pterygium(55.2%) 3. Age distribution of cataract showed the sixties 46.4%, the seventies 37.5% and the eighties($80{\leq}$) 16.1%. 4. As to the distribution corrected visual acuity in cataract ; 0.1 below(8.9%). 0.1~0.3(14.3%), 0.4~0.6(36.6%), 0.7 over(40.2%). 5. Age distribution of pterygium showed the sixties 60.9%, the seventies 26.1% and the eighties($80{\leq}$) 13.0%. 6. As to the distribution corrected visual acuity in pterygium ; 0.1 below(5.l%), 0.1~0.3(5.8%), 0.4~0.6(20.3%), 0.7 over(68.8%).

• Journal of Korea Water Resources Association
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• v.33 no.2
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• pp.169-179
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• 2000

The study was carried out to investigate the characteristics of vertical velocity distribution measured by current meter at Kangkyung station in Keum river during the period of 1995 to 1997. It suggests the quadratic parabola equation to estimate the vertical velocity profile only from the measurement data of surface velocity. The equation was found to be statistically very stable and showed high significance to express the surface velocity and bottom velocity. The vertical velocity profile was detennined by the relationships to the surface velocity, and a coefficient of the quadratic parabolic equation. The equation was verified to the reserved survey data, and the results were confirmed to be good for the estimation of the characteristics of the vertical velocity distribution. The vertical velocity profile can be applied to calculating the mean velocity and discharge, and to analyse the dispersion of pollutant materials in the streamflow.