• Journal of The Korean Astronomical Society
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• v.50 no.4
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• pp.131-138
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• 2017

We present a new catalog of AGB stars based on infrared two-color diagrams (2CDs) and known properties of the pulsations and spectra. We exclude some misclassified objects from previous catalogs. We identify color areas in two IR 2CDs where most O-rich and C-rich objects listed in previous catalogs of AGB stars are found. By collecting new objects in these color selection areas in the two IR 2CDs, we find candidate objects for AGB stars. By using the color selection method, we identify 3996 new objects in the O-rich areas, 1487 new objects in the C-rich areas, and 295 new objects in the overlap areas of the two 2CDs simultaneously. We have found that 470 O-rich and 9 C-rich objects are Mira variables with positive spectral identification and they are newly identified AGB stars. We present a new catalog of 3828 O-rich AGB stars and 1168 C-rich AGB stars excluding misclassified objects and adding newly identified objects.

• Structural Engineering and Mechanics
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• v.42 no.3
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• pp.425-448
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• 2012

In this paper, a new damage detection and quantification method has been presented to perform detection and quantification of structural damage under ambient vibration loadings. To extract modal properties of the structural system under ambient excitation, natural excitation technique (NExT) and eigensystem realization algorithm (ERA) are employed. Sensitivity matrices of the dynamic residual force vector have been derived and used in the parameter subset selection method to identify multiple damaged locations. In the sequel, the steady state genetic algorithm (SSGA) is used to determine quantified levels of the identified damage by minimizing errors in the modal flexibility matrix. In this study, performance of the proposed damage detection and quantification methodology is evaluated using a finite element model of a truss structure with considerations of possible experimental errors and noises. A series of numerical examples with five different damage scenarios including a challengingly small damage level demonstrates that the proposed methodology can efficaciously detect and quantify damage under noisy ambient vibrations.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.29-32
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• 2004

Reduction of methanol crossover in proton exchange membranes (PEMs) can be achieved by 1) the selection of materials, 2) the morphology control, and 3) the adequate crosslinking [1, 2]. The selection of polymer matrix of PEM for direct methanol fuel cells (DMFCs) is very important because the proton conductivity and methanol permeability are largely dependent upon the properties of polymers.(omitted)

• Archives of design research
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• v.15 no.1
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• pp.113-122
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• 2002

This thesis is focused on online education and proposes a guideline for selecting teaming theories and multimedia representation without difficulty. On the first, consideration of learning theories and analysis of multimedia properties are made, and from these results guidelines are formed. Then they are applied to each 6 types of CAI. Objectivism and constructivism could be used for the basic framework of CAI. The former is suitable for reed, sequential, structural, and passive learning style and the latter is suitable for selectable, unstructural, active, self-controled, learning style. And the quideline for selecting multimedia representation is made out of the properties of media, learners(cognitive model, proficiency, acceptance), and teaming contents. On the basis of guideline obtaining from the previous process, I suggest mosts suitable conditions for each 6 types of CAI available today. Those conditions are consist of learning theories, media selection, levels of learners, and categories and properties of teaming contents.

• The Journal of Korean Physical Therapy
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• v.29 no.2
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• pp.62-68
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• 2017

Purpose: This study was conducted to identify the impacts of stroke patients' general and disease-related properties on depression and family support. Methods: Subjects consisted of 79 persons who were diagnosed with cerebral hemorrhage and cerebral infarction and met the criteria for selection. The Korean version of Beck depression inventory (BDI) and a revision of the family support developed by Cobb were used. Frequency analysis of the subjects' general and medical history properties was conducted, and one way ANOVA was utilized to evaluate the degree of depression and family support with respect to the properties. Pearson's correlation coefficient was conducted to investigate the degree of depression and family support. Results: Participants showed no significant difference in depression based on the subjects' general and disease-related properties (p>0.05), although there were significant differences in family support based on marital status, hobbies and the medical expenses payers (p<0.05). The correlation between family support and depression was r=-0.491 (p<0.01). Conclusion: Through the results of this study, it was found that general and disease-related properties would not have any impact on depression while they would affect family support.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.5
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• pp.129-139
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• 2012

Accurate modeling rainfall induced landslide and slope stability requires a detailed knowledge of the distribution of material strength characteristics and suction distribution. However, material properties obtained from the drying cycle are still used for infiltration analysis in many cases, even though material properties of wetting cycle are quite different from those of drying cycle due to hydraulic hysteresis and air occlusion. Therefore, the selection of proper material properties such as soil-water retention curve (SWRC) and the hydraulic conductivity function (HCF) reflecting characteristics of wetting cycle and air occlusion is an essential prerequisite in order to simulate the infiltration phenomena and to predict the suction and water content distribution in unsaturated soils. It is concluded that the simulation of infiltration with material properties from the drying cycle did not reasonably match with experimental outputs. Further discussion is made on how to describe the material properties considering air occlusion during wetting cycle over the entire suction range in order to simulate infiltration phenomena.

• Korean Journal of Materials Research
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• v.30 no.12
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• pp.693-700
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• 2020

Direct water quenching technique can be used in hot stamping process to obtain higher cooling rate compared to that of the normal die cooling method. In the direct water quenching process, setting proper water flow rate in consideration of material thickness and the size of the area directly cooled in the component is important to ensure uniform microstructure and mechanical properties. In this study, to derive proper water flow rate conditions that can achieve uniform microstructure and mechanical properties, microstructure and hardness distribution in various water flow rate conditions are measured for 3.2 mm thick boron steel sheet. Hardness distribution is uniform under the flow condition of 1.5 L/min or higher. However, due to the lower cooling rate in that area, the lower flow conditions result in a drastic decrease in hardness in some areas in the hot-stamped part, resulting in low martensite fraction. From these results, it is found that the selection of proper water flow rate is an important factor in hot stamping with direct water quenching process to ensure uniform mechanical properties.

• Computers and Concrete
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• v.28 no.6
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• pp.567-583
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• 2021

The use of waste materials as a binder or aggregate in the concrete mixture is a great step towards sustainability in the construction industry. Waste rubber (WR) can be used as coarse and fine aggregates in concrete and improves the crack resistance, impact resistance, and fatigue life of the produced concrete. However, the mechanical properties of rubberized concrete degrade significantly by replacing the natural aggregate with WR. To have accurate estimations of the mechanical properties of rubberized concrete, two machine learning methods consisting of artificial neural network (ANN) and neuro-fuzzy system (NFS) were served in this study. To do this, a comprehensive dataset was collected from reliable literature, and two scenarios were addressed for the selection of input variables. In the first scenario, the critical ratios of the rubberized concrete and the concrete age were considered as the input variables. In contrast, the mechanical properties of concrete without WR and the percentage of aggregate volume replaced by WR were assumed as the input variables in the second scenario. The results show that the first scenario models outperform the models proposed by the second scenario. Moreover, the developed ANN models are more reliable than the proposed NFS models in most cases.

• Journal of KIISE:Software and Applications
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• v.29 no.8
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• pp.521-528
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• 2002

We propose a new approach to the feature selection for the classification of handwritten characters using two-dimensional(2D) wavelet packet bases. To extract key features of an image data, for the dimension reduction Principal Component Analysis(PCA) has been most frequently used. However PCA relies on the eigenvalue system, it is not only sensitive to outliers and perturbations, but has a tendency to select only global features. Since the important features for the image data are often characterized by local information such as edges and spikes, PCA does not provide good solutions to such problems. Also solving an eigenvalue system usually requires high cost in its computation. In this paper, the original data is transformed with 2D wavelet packet bases and the best discriminant basis is searched, from which relevant features are selected. In contrast to PCA solutions, the fast selection of detailed features as well as global features is possible by virtue of the good properties of wavelets. Experiment results on the recognition rates of PCA and our approach are compared to show the performance of the proposed method.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.78.3-78.3
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• 2015

About 70 high redshift quasars with $z{\geq}5$ have been discovered through combinations of standard broad-band filters to distinguish them from contaminating sources. However, among the discovered quasars so far, there is a redshift gap at $5{\leq}z{\leq}6$ due to the limitation of traditional filter sets and selection techniques. To understand the early mass growth of supermassive black holes and the final stage of the cosmic reionization, it is important to find a statistically meaningful sample of quasars with various physical properties. Here we suggest a new selection technique of high redshift quasars using medium-band filters: nine filters with bandwidths of 50nm and central wavelengths from 625 to 1025nm. Photometry with these medium-bands traces the spectral energy distribution (SED) of a source, similar to spectroscopy with R~15. We installed these filters to SED camera for QUasars in EArly uNiverse (SQUEAN) on the 2.1m telescope at McDonald Observatory, and conducted test observations of known high redshift quasars at $4.7{\leq}z{\leq}6.1$ and also dwarf stars for comparison. We found differences in SED shapes between high redshift quasars and dwarf stars, determined their locations on color-color diagrams, and demonstrated that the medium-band filters can enhance the efficiency of selecting robust quasar candidates in this redshift range. In this poster, we propose an effective selection method of high redshift quasars using these medium-band filters and discuss its effect on our high redshift quasar survey.