• 한국환경과학회지
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• 제8권5호
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• pp.587-592
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• 1999

The purpose of this study was to identify the controlling factors to construct tidal flat ecosystems having similar characteristics as natural ones. We transplanted the soil in a constructed tidal flat to a natural one and vice versa. Parameters monitored after these transplantations were silt content, organic matter, bacterial population and oxidation-reduction potential. Moreover, the relationship among silt content, organic matter and bacterial population was investigated by laboratory column experiment. The silt content, organic matter, bacterial population and vertical profile of oxidation-reduction potential in the soil transplanted from the constructed tidal flat to the natural one changed to similar values to those in the natural one. On the contrary, all the parameters for the soil transplanted from the natural tidal flat to the constructed one changed to similar values as those in the constructed one. The silt contents in thses two transplanted solis were in proportion to the organic carbon contents and bacterial population. Similarly, the bacterial population in laboratory column experiment increased with the increase in silt and organic matter contents. It seemed to be important to select a place to enhance accumulative of silt and/or to maintain the silt content by hydrodynamic control of seawater in order to construct a tidal flat having similar characteristics as natural one.

• 한국과학교육학회지
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• 제31권3호
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• pp.440-454
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• 2011

This study proposes a new instructional strategy and corresponding materials designed from various alternative frameworks to help students understand evolution as a biologically acceptable theory. Biology teachers have normally taught the evolutionary mechanism by means of comparing Lamarckism with natural selection. In this study, a new instructional strategy in which the Lamarckian explanation is first excluded because Lamarckism is known to be subsumed in a learner's cognitive structure as a strong preconception of evolution is suggested for teaching evolution. After mutation theory is introduced, Darwinism including natural selection is explained separately during the next class hour. Corresponding instructional materials that aid student understanding of the evolutionary mechanism were developed using recently published articles on human genetic traits as scientific evolutionary evidence instead of the traditional evolutionary subject matter, giraffe neck. Evolutionary evidence from human genetic traits allows students to exclude anthropocentric thoughts effectively and raise concern for the phenomenon of evolution positively. The administered instructional strategy and materials in this research improved student conception, concern, and belief of evolution and it is believed that they helped students understand the evolutionary mechanism effectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.320-326
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• 2002

Distribution system loss minimization re-configuration is 0-1 planning problem, and the number of combinations requiring searches is extremely large when dealing with typical system scales. For this reason, the application of a genetic algorithm (GA) seems attactive to solve this problem. Although Genetic algorithms are a type of random number search method, they incorporate a multi-point search feature and are therefore superior to one-point search techniques. The efficiency of GAs for solving large combinational problem has received wide attention. Further, parallel searching can be performed and the optimal solution is more easily reached. In this paper, for improving GA convergence characteristics in the distribution system loss minimization re-configeration problem, a chromosome "Limited Life" concept is intro duced. Briefly, considering the population homogenization and genetic drift problems, natural selection is achieved by providing this new concept, in addition to natural selection by fitness. This is possible because individuals in a population have an age value. Simulations were carried out using a model system to check this method's validity.

• 한국환경과학회지
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• 제20권12호
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• pp.1561-1584
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• 2011

This study aims at classifying and interpreting on the vegetation structure and analyzing the correlationship between communities and environmental conditions in Mt. Wolchulsan. We also predicted the succession possibility and the vertical distribution change of vegetations according to the global warming, through the pioneer species of a forest change and dominant species of canopy vegetations. We also analyzed the Raunkiaer's life-form. The communities in this ecotone are distributed vertically in the order of a Quercus acuta community, a Q. serrata-Q. variabilis community and a Q. serrata community. A Pinus densiflora community appears on the most of altitudes. The distribution of communities correlates highly with an altitude. The Q. serrata-Q. variabilis community will be succession to the Q. acuta community, and the Q. variabilis will be under natural selection gradually or remain locally. The Q. serrata community will possibly maintain as it is, and the P. densiflora community will be also under natural selection gradually. The valuable quantitative and numerical life-forms are confirmed and the layer structure of present vegetation will not be changed.

• 한국기계가공학회지
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• 제8권1호
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• pp.10-17
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• 2009

Spindle design is very important for the improvement of the competitive power in production cost of high quality machine tools. The important factor in spindle design is not only to improve the natural frequency of spindle but also to reduce displacement of spindle end. In this paper, parameters those influence on static and dynamic stiffness of high-speed spindle have selected form preceding studies. And those selected parameters are applied to Taguchi Method. To perform FEM analysis, bearing conditions are selected with optimized condition. To know how to improve static and dynamic stiffness of machine tool spindle, natural frequency and displacement of spindle end are obtained by FEM analysis. The Taguchi Method was used to draw optimized condition of bearing position and it's stiffness. From these results, amplitude of vibration is enough good less than $3{\mu}m$ pk-pk of the spindle of 40,000rpm manufactured in this work by the optimal design.

• 농촌계획
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• 제6권2호
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• pp.43-49
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• 2000

Buffer zone selection technique for natural purification of livestock wastewater within a small agricultural watershed was developed using Geographic Information Systems. The technique was applied to $4.12\;km^2$ watershed located in Gosan-myun, Ansung-gun which have 20 livestock farmhouses. As a necessary data for selecting process, feedlot site map, digital Elevation Model (DEM), stream network, soil and land use map were prepared. By using these data, wastewater moving-path tracing program from each feedlot to the stream was developed to get the basic topographic factors; average slope through the paths, distance to the nearest stream and watershed outlet. To identify the vulnerable feedlots for storm event, the grid-based storm runoff model (Kim, 1998; Kim et al., 1998) was adopted. The result helps to narrow down the suitable area of buffer zone, and finally by using subjective but persuasive conditions related to elevation, slope and land use, the suitable buffer zones were selected.

• 한국환경복원기술학회지
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• 제14권6호
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• pp.1-15
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• 2011

We recently witnessed increasingly more natural disturbances on forested land. On the other hand, only limited number of nursery grown tree species are available for restoration projects. At the same time, so little on the disturbance resistance of species has been studied that a selection of right species for right site condition becomes very difficult. This study is a compilation of the site specificities and disturbance resistance of each species native to South Korea. Each species was surveyed for 11 items related to site specificities, and 12 items related to disturbance resistance including the resistance to snow damage. This study was conducted for 161 tree species from 44 families : 21 evergreen conifer species, 2 deciduous conifer species, 18 evergreen broad-leaved species, 118 deciduous broad-leaved species, and 2 monocotyledon species. This study suggests that native species in South Korea show resistance to all types of natural disturbances except drought.

• The Journal of Asian Finance, Economics and Business
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• 제8권4호
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• pp.571-580
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• 2021

The study explores the factors affecting the brand selection behavior of retail chains in Vietnam and to what extent they have an impact on the customer's choice intention. This research employs a combination of both qualitative and quantitative mixed methods with the help of SPSS version 22.0 in data analysis. Expert interviews are used to design the questionnaire for the survey conducted on 700 consumers. Research results show that the eight factors of store image (1-to-3 split factor of store image including the display of goods and services), price perception, risk perception, brand attitude, brand awareness, and brand familiarity were determined. They all influence the intention to choose the retail chain brand. With a positive β coefficient, the more store image, price perception, brand attitude, and brand awareness are enhanced, the more likely the intention to choose the retail chain brand. The factor of risk perception has negative ��, resulting in an inverse impact on choosing a retail chain brand name. Price perception and risk perception have the strongest impact on retail chain decision behavior while commodity display factors the least. Based on these important results, the study proposes implications for retailers and manufacturers.

• Genomics & Informatics
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• 제20권4호
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• pp.43.1-43.18
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• 2022

Atropa belladonna is a valuable medicinal plant and a commercial source of tropane alkaloids, which are frequently utilized in therapeutic practice. In this study, bioinformatic methodologies were used to examine the pattern of coding sequences and the factors that might influence codon usage bias in the chloroplast genome of Atropa belladonna and other nightshade genomes. The chloroplast engineering being a promising field in modern biotechnology, the characterization of chloroplast genome is very important. The results revealed that the chloroplast genomes of Nicotiana tabacum, Solanum lycopersicum, Capsicum frutescens, Datura stramonium, Lyciumbarbarum, Solanum melongena, and Solanum tuberosum exhibited comparable codon usage patterns. In these chloroplast genomes, we observed a weak codon usage bias. According to the correspondence analysis, the genesis of the codon use bias in these chloroplast genes might be explained by natural selection, directed mutational pressure, and other factors. GC12 and GC3S were shown to have no meaningful relationship. Further research revealed that natural selection primarily shaped the codon usage in A. belladonna and other nightshade genomes for translational efficiency. The sequencing properties of these chloroplast genomes were also investigated by investing the occurrences of palindromes and inverted repeats, which would be useful for future research on medicinal plants.

• Steel and Composite Structures
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• 제49권6호
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• pp.633-643
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• 2023

In this study, the natural frequencies of Functional Graded Materials (FGM) plates are predicted using Artificial Neural Network (ANN). A model based on Third-order Shear Deformation Theory (TSDT) and FEM is used to train the ANN model. Different training methods are tested to simulate input and output dependency. As this is a parametric model, several architectures and optimization algorithms were tested. The proposed model allows us to minimize the CPU time to evaluate candidate material properties for FGM plate material selection and demonstrate their influence on dynamic behavior. Consequently, the time required for the FGM design process (candidate materials for material selection) and the geometric optimization of the FGM structure would remain reasonable. The ANN model can help industries to produce FGM plates with good mechanical properties of the selected materials. I addition, this model can be used to directly predict vibration behavior by testing a large number of FGM plates, representing all possible combinations of metals and ceramics in today's industry, without having to solve any eigenvalue problems.