• Journal of the Korean Geotechnical Society
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• v.20 no.6
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• pp.75-83
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• 2004

This study is focused on the constitutive model in order to represent brittleness and dilatancy of cohesionless soils. The constitutive model was proposed on the basis of an anisotropic hardening rule with generalized isotropic hardening rule. The shape of yield surface is a simple cylinder type in stress space and it makes the model practically useful. Flow rule was approximated by a concrete function on dilatancy. A peak stress ratio was defined to model brittle stress-strain relationships. The proposed model was formulated and implemented to calculate the stress-strain relationship from triaxial tests. In the companion paper the proposed model will be verified by comparison with the triaxial test results.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.872-878
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• 2013

In industrial control systems, flow measurement is a very important issue. It is frequently needed to calculate how much total fluid or gas flows through a cross-section. Flow volume measurement tools use simple sampling or rectangle methods. Actually, flow volume measurement process is an integration process. For this reason, measurement systems using instantaneous sampling technique cause considerably high errors. In order to make more accurate flow measurement, numerical integration methods should be used. Literally, for numerical integration method, Rectangular, Trapezoidal, Simpson, Romberg and Gaussian Quadrature methods are suggested. Among these methods, trapezoidal rule method is quite easy to calculate and is notably more accurate and contains no restrictive conditions. Therefore, it is especially convenient for the portable flow volume measurement systems. In this study, the volume measurement of air which is flowing through a cross-section is achieved by using PLC ladder diagram. The measurements are done using two different approaches. Trapezoidal rule method is proposed to measure the flow sensor signal to minimize measurement errors due to the classical sampling method as a different approach. It is concluded that the trapezoidal rule method is more effective than the classical sampling.

• Journal of Information Processing Systems
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• v.13 no.6
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• pp.1496-1515
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• 2017

One of the most visible developments in Decision Support Systems (DSS) was the emergence of rule-based expert systems. Hence, despite their success in many sectors, developers of Medical Rule-Based Systems have met several critical problems. Firstly, the rules are related to a clearly stated subject. Secondly, a rule-based system can only learn by updating of its rule-base, since it requires explicit knowledge of the used domain. Solutions to these problems have been sought through improved techniques and tools, improved development paradigms, knowledge modeling languages and ontology, as well as advanced reasoning techniques such as case-based reasoning (CBR) which is well suited to provide decision support in the healthcare setting. However, using CBR reveals some drawbacks, mainly in its interrelated tasks: the retrieval and the adaptation. For the retrieval task, a major drawback raises when several similar cases are found and consequently several solutions. Hence, a choice for the best solution must be done. To overcome these limitations, numerous useful works related to the retrieval task were conducted with simple and convenient procedures or by combining CBR with other techniques. Through this paper, we provide a combining approach using the multi-criteria analysis (MCA) to help, the traditional retrieval task of CBR, in choosing the best solution. Afterwards, we integrate this approach in a decision model to support medical decision. We present, also, some preliminary results and suggestions to extend our approach.

• Journal of the Korea Society of Computer and Information
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• v.20 no.1
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• pp.207-216
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• 2015

The development of IT technology has brought many changes in military operations. For example, the way of transmitting and receiving information from one another has changed. Partiicularly, in the case of the ROK Navy, they utilize encrypted real-time chattig over wire wireless network in operations and tranings. However, text communication is being utilized more in exanging of simple informations, and not for the partical informations required in the operations and exercises, doctrines and guidebooks are still being used in these cases. Therefore, I have designed a rule-based engine which can provide real-time informations by linking ECA rules to text communication, and it has been verified by running virtual scenarios. As a rusult, this engine showed an accuracy of 83%.

• Journal of Korean Clinical Health Science
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• v.9 no.1
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• pp.1478-1485
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• 2021

Purpose. To analysis of astigmatism in Korean adults from 20 to 29 years old. Methods. From January 2019 to February 2020, one hundred two subjects were performed in refraction test using the Auto-Refractometry. Results. In the type of astigmatism based on refractive error, the male's right eye was 4.26% simple myopic astigmatism and 95.74% complex myopic astigmatism, and the left eye was 2.22% simple myopic astigmatism and 97.78% complex myopic astigmatism. However, in the female's right eye, simple myopic astigmatism was 2.27%, complex myopic astigmatism was 97.73%, and left eye was simple myopic astigmatism was 2.17%, complex myopic astigmatism was 97.83%. The types of astigmatism in men and women similar to other. The mean refractive astigmatism values were -0.922±-0.798 diopter and -0.877±-0.707 diopter for male right and left eye, and -0.765±-0.599 diopter and -0.853±-0.586 diopter for female. On the other hand, the refraction values of the right and left eyes of men and women have statistical significance(p=0.000). The mean power comparative between refractive astigmatism and corneal astigmatism power were -0.186±-0.745 diopter, -1.091±-0.589 diopter in male and -1.140±-0.593 diopter, -1.140±-0.534 diopter in female. Therefore, the mean power values of the refractive astigmatism and corneal astigmatism of men and women were statistical significance(p=0.000). At the 0.75 diopter or more, which can have clinical symptoms of astigmatism power, males have 60.86% and 72.09% of the right and left eyes, and females have 47,64% and 60.10% of the right and left eyes. At 0.75 diopter or more, which can have clinical symptoms of corneal astigmatism power, males have 68.75% and 74% of the right and left eyes, and females have 86.50% and 82.35% of the right and left eyes. In the type of astigmatism axis, both men and women had a high frequency of the rule astigmatism. However, men had a high frequency of against-the-rule astigmatism and women showed a high frequency of oblique astigmatism. Conclusions. In this study, the complex myopic astigmatism and with-the rule astigmatism was the most common of all subjects. However, there was a statistical significance between right and left eyes of all subjects. The corneal astigmatism was higher refractive values in both males and females than refractive astigmatism. This study suggests that the analysis of the astigmatism can provide the useful diagnosis information for the correction of visual acuity.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.691-700
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• 1994

Voronoi diagram of a set of geometric entities on a plane such as points, line segments, or arcs is a collection of Voronoi polygons associated with each entity, where Voronoi polygon of an entity is a locus of point which is closer to the associated entity than any other entity. Voronoi diagram is one of the most fundamental geometrical construct and well-known for its theoretical elegance and the wealth of applications. Various geometric problems can be solved with the aid of Voronoi diagram. For example, the maximum tool diameter of a milling cutter for rough cutting in a pocket can be easily found, and the pocketing tool path can be efficiently generated from Voronoi diagram. In PCB design, the design rule checking can be easily done via Voronoi diagram, too. This paper discusses an algorithm to construct Voronoi diagram of a simple polygon which consists of simple curves such as line segments as well as arcs in a plane with O(nlogn) time complexity by employing the divide and conquer scheme.

• Proceedings of the Korean Institute of Interior Design Conference
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• 1999.04a
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• pp.94-97
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• 1999

The purpose of this study was to prepare the visual communication tool, which would be used for the interior design consulation to reduce the communication gap between an interior designer and a client. To achieve the study purpose, review of literature, questionnaire survey, qualitative analysis and design research methods were used. The major results of this study were as follows: 1) "Image Cube" was designed as a comprehensive rule to classify interior image types. By this, eight interior image types were classified: SFU(Simple-Formal-Urbane), SFN(Simple-Formal-Natural), SCU(Simple-Casual-Urbane), SCN(Simple-Casual-Natural), DFU(Decorative-Formal-Urbane), DFN(Decorative-Formal-Natural), DCU(Decorative-Casual-Urbane), DCN(Decorative-Casual-Natural). 2) The Interior image collages were composed to present the overall feeling of each interior image type. 3) The Interior image models which would be used as the standard to be modified to various sub-types through the interior design consultation were produced corresponding to interior image types.age types.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.65-69
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• 2001

To investigate the visual acuity of the primary school children. This study was researched visual acuity test using objective and subjective methods. 1. The eye types were 90.3% positive for myopia, 3.1% for emmetropia, 4.9% hyperopia, 1.7% for mired astigmatism. 2. The abnormal refraction eyes were 58.6% positive for simple myopia, 29.9% for myopic compound astigmatism, 5.1% for my optic simple astigmatism and 1.9% for simple hyperopia, 1.9% for hyperopic compound astigmatism, 1.3% for hyperopic simple astigmatism, 1.3% for mixed astigmatism. 3. The axis of astigmatism were 85.7% for astigmatism with-the-rule, 9.3% for astigmatism against-the-rule, 5.0% for astigmatism oblique. 4. On total myopic spheric power. the -0.50

• Journal for History of Mathematics
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• v.13 no.1
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• pp.99-112
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• 2000

In this paper we discuss the teaching methods about statistical inferences. Bayesian methods have the attractive feature that statistical conclusions can be stated using the language of subjective probability. Simple methods of teaching Bayes' rule described, and these methods are illustrated for inference and prediction problems for one proportions. Also, we discuss the advantages and disadvantages of traditional and Bayesian approachs in teaching inference.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.3
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• pp.173-181
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• 2019

To estimate probabilistic distribution function from experimental data, kernel density estimation(KDE) is mostly used in cases when data is insufficient. The estimated distribution using KDE depends on bandwidth selectors that smoothen or overfit a kernel estimator to experimental data. In this study, various bandwidth selectors such as the Silverman's rule of thumb, rule using adaptive estimates, and oversmoothing rule, were compared for accuracy and conservativeness. For this, statistical simulations were carried out using assumed true models including unimodal and multimodal distributions, and, accuracies and conservativeness of estimating distribution functions were compared according to various data. In addition, it was verified how the estimated distributions using KDE with different bandwidth selectors affect reliability analysis results through simple reliability examples.