• The Journal of the Petrological Society of Korea
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• v.20 no.1
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• pp.23-37
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• 2011

The scaling properties on the length distribution of microcrack populations from Tertiary crystalline tuff are investigated. From the distribution charts showing length range with 15 directional angles and five groups(I~V), a systematic variation appears in the mean length with microcrack orientation. The distribution charts are distinguished by the bilaterally symmetrical pattern to nearly N-S direction. The whole domain of the length-cumulative frequency diagram for microcrack populations can be divided into three sections in terms of phases of the distribution of related curves. Especially, the linear middle section of each diagram of five groups represents a power-law distribution. The frequency ratio of linear middle sections of five groups ranges from 46.6% to 67.8%. Meanwhile, the slope of linear middle section of each group shows the order: group V($N60{\sim}90^{\circ}E$, -2.02) > group IV($N20{\sim}60^{\circ}E$, -1.55) > group I($N60{\sim}90^{\circ}W$, -1.48), group II($N10{\sim}60^{\circ}W$, -1.48) > group III($N10^{\circ}W{\sim}N20^{\circ}E$, -1.06). Five sub-populations(five groups) that closely follow the power-law length distribution show a wide range in exponents( -1.06 - -2.02). These differences in exponent among live groups emphasizes the importance of orientation effect. In addition, breaks in slope in the lower parts of the related curves represent the abrupt development of longer lengths, which is reflected in the decrease in the power-law exponent. Especially, such a distribution pattern can be seen from the diagram with $N10{\sim}20^{\circ}E,\;N10{\sim}20^{\circ}W$ and $N60{\sim}70^{\circ}W$ directional angles. These three directional angles correspond with main directions of faults developed around the study area. The distribution chart showing the individual characteristics of the length-cumulative frequency diagrams for 15 directional angles were made. By arraying above diagrams according to the categories of three groups(A, B and C), the differences in length-frequency distributions among these groups can be easily derived. The distribution chart illustrates the importance of analysing microcrack sets separately. From the related chart, the occurrence frequency of shorter microcracks shows the order: group A > group B > group C. These three types of distribution patterns could reveal important information on the processes occurred during microcrack growth.

• Journal of The Korean Association For Science Education
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• v.17 no.3
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• pp.229-237
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• 1997

Due mainly to the complexity of educational system, it is difficult to comprehend the phenomena and nature of the science education. Educators have developed various kinds of means and methods useful for easy understanding of the phenomena and nature. This study added another method supporting that the phenomena and nature of the science education should be understood in the context of educational system. System approach into thought is holistic and contextual in nature. It focuses on both the whole and its relevant parts, and is concerned with environmental context. By its definition, a system interact not only with another system but also with its environments. The purpose of this study was to answer such questions as "What is the science education?", or "What is the meaning of the science education?", "Why do we teach science?", "Why are we ought to teach science?", and "How do we know that those facts and methods are valid?" The results for the study are as follows: 1. Science education is the human behavior with the purpose to attain something through science and education. It is socio-cultural process, social and organizational activity into which the public deeply involved. The process and activity are usually undergirded upon the value of science education. 2. The science education system is analyzed in the light of the legislative institution. The system model that characterize of the system and the interrelationship among the systems is suggested in terms of the conceptions of boundary, components, variables, parameters and linkage, etc. Then, the science education system is divided into the plan-system, do-system and see-system by the use of the criterion of plan-do-see that is the general process of human activity. The study also identified that the system of science education is consisted of the aspects of science education administration, school science education, and science education evaluation. 3. As the frame of thought on the contextuality in the science education system, the contexts of meaning, organization, legislation and policy were presented, along with the main cognitive interest, the system, the orientation, and the premise of each context which were used to explain the reasons. The results of this study suggested a new approach into the comprehension of the educational phenomena in teaching science and the possibility of understanding science education as a whole.

• Economic and Environmental Geology
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• v.13 no.3
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• pp.167-184
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• 1980

The granitic plutons associated with Ogcheon geosynclinal zone can be grouped into three different subzones; SE-Subzone for the migmatitic and schistose granites of the southeast margin, 101-181m.y. old; NW-Subzone for those of the northwest margin, 112-163m. y. old; and C-Subzone for those of central part of the zone, 63-183m.y. old. The intrusives in C-Subzone are further subdivided into the older, adamellite to granodiorite (148-183m.y. old) and the younger, perthitic granites (63-106m,y. old). The metallogenic distribution of South Korea suggests that, in the Ogcheon Zone, it is possible to delineate an elongated polymetallogenic province in the general orientation of the zone intimately related with the migmatite and plutonic zones mentioned. Moreover, the mineralization in the province was basically controlled by the patterns of local geology involving country rocks and related igneous bodies, that permit subdivision of the province into the following three parts: Northeast (NE) Province consists dominantly of thick Paleozoic calcareous sediments; Middle (M) Province is characterized by predominant argillaceous and partly calcareous sediments of Precambrian to Late Paleozoic age; and Southwest (SW) Province consisting mainly of volcanic and arenaceous sediments of Mesozoic age. The three different plutonic zones with three different country rock provinces above mentioned make a combination which consists of nine classes. Each class can be assumed to be characterized by specific mineralization type. In order to classify the mineralization types, the present study sampled twenty six ore deposits and mineralized areas in Ogcheon zone as shown figure 2; eight ore deposits from plutonic SE-Subzone, ten from the plutonic NE-Subzone and eight from the plutonic C-Subzone. The characteristics of the classes are as follows: NE-SE is predominant in Au-Ag vein and Sn-migmatite of katazonal occurrence; NE-C is most productive in Pb-Zn and remarkable in Fe contact deposit in mesozone and partly Pb-Zn-Cu skarn in limestone and subordinate in mesozone and partly Pb-Zn pipes; M-SE is considerable in Au-Ag vein and rare elements (Nb, Ta, etc.) of pegmatite; M-C is predominant in F-veins in epizone and Mo-W, Fe, Cu veins occur in replacement type; M-NW is productive in Fe metamorphic and skarn types, partly remarkable in Cu, Pb-Zn contact; SW-SE is barren in mineralization related to Jurassic igneous rocks; SW-C is predominant in alunite and pyrophyllite in tuffs; and SW-NW is scarece in Pb-Zn, Cu, As and Au-Ag veins.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.136-142
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• 2018

Additive manufacturing process technology, known as the 3D printing process, is expanding its utilization from simple model realization to commercialized part production based on continuous material development. Recently, research and development have been actively carried out to fabricate lightweight and high-strength parts using polymers, such as polyamide (polyamide), which is a high-strength engineering plastic material. In this study, the Izod impact characteristics were analyzed for polyamide 12 (PA12) materials. For the specimen production, selective laser sintering process technology, which has excellent mechanical properties of finished products, was applied. In addition, PA12 and glass bead reinforced PA12 materials were produced. The specimens were classified according to the production direction on the production platform, and each specimen was subjected to an Izod test at test temperatures of $-25^{\circ}C$, $25^{\circ}C$, and $60^{\circ}C$. As a result, the impact strength of PA12 and glass bead-reinforced PA12 of vertical direction specimens were 48.8% and 16.3% lower than those of the parallel specimens at a $25^{\circ}C$ test temperature and the impact strength of parallel specimens was improved by 46.5% and 20.4% at a test temperature of $60^{\circ}C$ compared to that at $-25^{\circ}C$.

• The Journal of the Korea Contents Association
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• v.18 no.7
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• pp.272-281
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• 2018

The purpose of this study was to examine the influence of an academic tutoring program on interpersonal relationships, self- directed learning capability and academic self-efficacy. The research question posed in this study was whether an academic tutoring program would affect interpersonal relationships, self-directed learning capability and academic self-efficacy. To address the research question, a self-administered survey was conducted to gather data on 214 students who participated in an academic tutoring program during a semester from September 4 to November 10, 2017. The findings of the study were as follows: After their participation in the tutoring program, there was a little decrease in self-directed learning capability and personal learning orientation, and they made progress in interpersonal relationships and academic self-efficacy. By gender, there was the greatest improvement in interpersonal relationships as well after their participation in the tutoring program. By academic year and motivation for participation, they showed the best improvement in interpersonal relationships as well, followed by academic self-efficacy. In other words, it could be said that the parts which the tutoring program brought about the biggest change to and worked best on were interpersonal relationships and academic self-efficacy. In conclusion, the improvement of interpersonal relationships and academic self-efficacy could boost not only the school adjustment of students but their academic levels and then eventually prevent them from dropping out. Therefore this program seems to be one of outstanding learning programs that could make a contribution to the stable management and qualitative competitiveness of universities.

• Geophysics and Geophysical Exploration
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• v.4 no.1
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• pp.8-18
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• 2001

To delineate the inhomogeneities including fractures and to estimate the freshness of rock borehole radar consisting of the reflection and tomography methods, and GPR surveys were conducted at a granite quarry mine. The borehole reflection survey using the direction finding antenna was also conducted to get the spatial orientations of reflectors. 20 MHz was adopted as the central frequency for the borehole radar reflection and tomography surveys and 100 MHz was for GPR. Through the interpretation of borehole reflection data using dipole and direction finding antenna as well as GPR images, which are good agreement with each other, we could determine the orientation of the major fractures in three dimensional way. Parts of travel time curves of tomography data showed the anisotropy, which is uncommon in granite quarry. By comparing the tomography data and TeleViewer images, the anisotropy effect in this area are closely related to fine fissures aligned in the same direction. The area confined by the two fractures, MF2 and MF5, might consist of the most fresh granite in the surveyed area, which was concluded from the borehole radar tomography, and GPR images as well as the distribution of anisotropy.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.13 no.5
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• pp.131-154
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• 2018

While strong investments on startup and venture ecosystem prosper worldwide, growing interest on nurturing startup ecosystem in Korea is also on its way. However, korean entrepreneurial ecosystem currently results few successful business models with those continuous development of itself compared to the one in China, which is breeding more than 50% of unicorns internationally. Accordingly, this study examined how people in the venture ecosystem, especially in IT industry feel about themselves and startup itself and compared startup ecosystem in Seoul, Korea to the one in Chengdu, China considering each of economic, social and administrational environment. The study tried to provide an implication about the future orientation of Korea's starup and venture ecosystem to policy makers and the ones inside the environment to make a better one. Therefore, the study choose Seoul, Korea and Chengdu, China as geological specimens of startup ecosystem and conduct qualitative study by interviewing selected ones who work in startup incubator, accelerator specified to IT industry and started their own business in IT industry funded by startup reward program. The study categorize the result in social, economic, and administrative parts and screens whether the interviewees from both Korea and China have similar opinions toward each of questions and can be translated to have tendency or not in each part of study. According to the study, the national recognition of startup should be moved from means of maintenance such as restaurants, franchise business to IT startup especially based on software business for the sustainable flourish in Korean venture ecosystem. Investors including accelerator, Angel investors and VCs should be less risk-aversion and therefore prefer stake purchase to solely giving subsidies. The role of governors should be limited to be a middleman of the network, connecting each people in need inside the ecosystem and their reward program should focus on nurturing the growing ones, not just multiplying the numbers of startups to expand the size of entrepreneurial ecosystem. Since this study indicated that entire revision of startup ecosystem should be applied to make a better one, it could be used to design future entrepreneurial infrastructure and the ways of activating startup ecosystem elsewhere in Korea.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.5
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• pp.404-411
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• 2009

We introduce in this paper a new method for smooth foldover-free warping of images, based on the vector field deformation technique proposed by Von Funck et al. It allows users to specify the constraints in two different ways: positional constraints to constrain the position of a point in the image and gradient constraints to constrain the orientation and scaling of some parts of the image. From the user-specified constraints, it computes in the image domain a C1-continuous velocity vector field, along which each pixel progressively moves from its original position to the target. The target positions of the pixels are obtained by solving a set of partial derivative equations with the 4th order Runge-Kutta method. We show how our method can be useful for texture mapping with hard constraints. We start with an unconstrained planar embedding of a target mesh using a previously known method (Least Squares Conformal Map). Then, in order to obtain a texture map that satisfies the given constraints, we use the proposed warping method to align the features of the texture image with those on the unconstrained embedding. Compared to previous work, our method generates a smoother texture mapping, offers higher level of control for defining the constraints, and is simpler to implement.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.4
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• pp.317-324
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• 2013

Twitter sentiment analysis is to classify a tweet (message) into positive and negative sentiment class. This study deals with SentiWordNet(SWN)-based twitter sentiment analysis. SWN is a sentiment dictionary in which each sense of an English word has a positive and negative sentimental strength. There has been a variety of SWN-based sentiment feature extraction methods which typically first determine the sentiment orientation (SO) of a term in a document and then decide SO of the document from such terms' SO values. For example, for SO of a term, some calculated the maximum or average of sentiment scores of its senses, and others computed the average of the difference of positive and negative sentiment scores. For SO of a document, many researchers employ the maximum or average of terms' SO values. In addition, the above procedure may be applied to the whole set (adjective, adverb, noun, and verb) of parts-of-speech or its subset. This work provides a comparative study on SWN-based sentiment feature extraction schemes with performance evaluation on a well-known twitter dataset.

• Composites Research
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• v.12 no.5
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• pp.31-39
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• 1999

Glass-fiber reinforced polymeric composites provide the desitable properties of high stiffness and strength as well as specific weight. Hence, they have become some of the most important materials in several industries. These composites can be grouped into thermoplastic and thermoset composites, with thermoplastic composites having several advantages over thermoset composites in mechanical properties and processing. As a result, the study of the material behavior and forming techniques of such composites has attracted considerable attention in recent years. When the continuous fiber-reinforced polymeric composites are molded by flow molding, the molded parts leads to be nonhomogeneity and anisotropic because of the separation and orientation of fibers. As the characteristics of the products are greatly dependent on the separation, it is very important to clarify the separation in relarion to molding conditions, fiber mat structures and mold geometry. In this study, the effects of the mold geometry and the fiber mat structure on the compression moldability are studied using the cup-type molding.