• Journal for History of Mathematics
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• v.21 no.3
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• pp.143-156
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• 2008

In this study, we divided the teaching and learning of proof into three steps in the demonstrative geometry of the middle school mathematics. And then we surveyed the student's difficulties in the teaching and learning of proof by using of questionnaire. Results of this survey suggest that students cannot only understand the meaning of proof in the teaching and learning of proof but also they cannot deduce simple mathematical reasoning as judgement for the truth of propositions. Moreover, they cannot follow the hypothesis to a conclusion of the proposition It results from the fact that students cannot understand clearly the meaning and the role of hypotheses and conclusions of propositions. So we need to focus more on teaching students about the meaning and role of hypotheses and conclusions of propositions.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.6
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• pp.530-539
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• 2015

A business model (BM) can be developed based on a business model framework (BMF) consisting of key components such as value proposition, customers, and resources. To systematically generate and analyze emerging BMs such as healthcare BM, an integration of diverse BMF components is needed. The present study is to establish a comprehensive BMF and evaluate its applicability to healthcare BMs. Based on a review of eight BMF studies, ten BMF components were identified and classified into five major components (value proposition, resources, organizing model, customers, and revenue model) and five minor components (technology, service platform, delivery, competitive strategy, and growth/exit) by analyses of frequency and functional importance. Lastly, the BMs of three emerging healthcare companies (WellDoc, Inc., CFW Shops, and Aravind Eye Care System) were analyzed and compared in terms of the proposed BMF components. The comprehensive BMF components presented in the study can be of help for developing new BMs and analyzing the strengths and weaknesses of BMs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.909-914
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• 2002

In this thesis, noise reduction of image with impulse noise in circle image removed noise to harness existing median filter for noise reduction from image data of damage by noise when impulse noise is high or noise reduction is low, but it is not made up of noise reduction to harness existing median filter in case of existence of non-impulse noise. Therefore noise reduction of image with non-impulse noise had to remove noise by morphological arithmetic in this thesis's proposition. In contrast to median filtering, result of edge detection is more efficient after remove non-impulse noise by method of thesis's proposition and it compare and demonstrate through this experimentation.

• Journal of Educational Research in Mathematics
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• v.18 no.1
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• pp.123-135
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• 2008

This study analysed the schemata which are requisite to understand and prove examples of mathematical induction, and examined students' construction of the schemata. We verified that the construction of implication-valued function schema and modus ponens schema needs function schema and proposition-valued function schema, and needs synthetic coordination for successive mathematical induction schema. Given this background, we establish $1{\sim}4$ levels for students' understanding of the mathematical induction. Further, we analysed cognitive difficulties of students who studying mathematical induction in connection with these understanding levels.

• Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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• v.7
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• pp.215-235
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• 2003

Karl $B\"{u}hlers$ Sprachtheorie orientiert sich an der Psychologie. Das zeigt sich im zweten Teil dieser Arbeit. $Au{\ss}erdem$ haben wir da gesehen, wie $pl\"{o}tzlich$ er im deutschen Gebiet seine Wissenschaft abbrechen und so eilig nach Amerika auswandern musste. Damit konnte er sein wissenschaftliches Ziel, also allgemeine Sematologie im Sinne der Logik der $Humanit\"{a}t$, nicht erreichen. Aber trotzdem $la{\ss}t$ sich erwarten, dass wir mit seinem $unverg\"{a]nglichen$ Buch und anderen Daten wieder starten $k\"{o}nnen$. Er nennt das Sprechereignis, das unsere Sinne $r\"{u}hrt$, den ersten Gegenstand der Sprachwissenschaft. Das ist etwas Einmaliges, ein Geschehen hier und jetzt im bestimmten Zeitraum. Das anschauliche Zeigen $geh\"{o}rt$ so zum Wesen der $nat\"{u}rlichen$ Sprache wie die Abstraktion und das begriffliche Erfassen der Welt. Karl $B\"{u}hler$ spricht von dem anschaulichen Zeigen, weil er betonen wollte, dass Deixis an die Weltanschauung gebunden ist; symbolische $Ausdr\"{u}cke$ sind begrifflich andererseits, weil sie von der Sprechsituation $unabh\"{a}ngig$ sind. Die zwei Elemente, die zum vollendeten Erkenntnis $geh\"{o}ren$, sind unelinierbar in jedem $Sprachph\"{a}nomen$ enthalten. Wir mobilisieren die zwei auf jeden fall zu unserem vollendeten Erkenntnis der Welt. Ich habe die These mit der Formel S = M$\times$P beschrieben, die als Cartesisches Produkt von pragmatischen Komponent und Proposition interpretiert werden soll. Diese $Erkl\"{a}rung$ kann auch $ad\"{a}quat$ auf Zeichensinterpretation angewandt werden.

• Journal of Information Technology Applications and Management
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• v.20 no.4
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• pp.191-205
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• 2013

Recently, the topic of predicting interpersonal trust in online social networks is receiving considerable attention, because trust plays a critical role in controlling the spread of distorted information and vicious rumors, as well as reducing uncertainties and risk from unreliable users in social networks. Several trust prediction models have been developed on the basis of transitivity and composability properties of trust; however, it is hard to find empirical studies on whether and how transitivity and composability properties of trust are operated in real online social networks. This study aims to predict interpersonal trust between two unknown users in social networks and verify the proposition on whether and how transitivity and composability of trust are operated in social networks. For this purpose, we chose three social network sites called FilmTrust, Advogato, and Epinion, which contain explicit trust information by their users, and we empirically investigated the proposition. Experimental results showed that trust can be propagated farther and farther along the trust link; however, when path distance becomes distant, the accuracy of trust prediction lowers because noise is activated in the process of trust propagation. Also, the composability property of trust is operated as we expected in real social networks. However, contrary to our expectations, when the path is synthesized more during the trust prediction, the reliability of predicted trust did not tend to increase gradually.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.565-568
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• 2006

This study evaluates the physical mchanical properties, durability of porous concrete for pavement according to content of polymer and steel fiber to elicit the presentation of data and the way to enhance its function for the practical field application of porous concrete as a material of pavement. The results of the test indicate that in every condition, the void ratio and the coefficient of water permeability of porous concrete for pavement satisfy both the domestic standards and proposition values. Among the properties of strength, the compressive strength satisfies the standards in the specification of Korea National Housing Corporation as for every factor of mixture but in the case of the flexural strength, more than 0.6Vol.% of steel fiber satisfied the Japan Concrete Institute proposition values. The case when 0.6Vol.% of steel fiber and 10Wt.% of polymer are used at the same time shows that the loss rate of mass by Cantabro test became 36.7% better and freeze-thaw resistance became 33% better.

• Journal of Information Technology Services
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• v.15 no.4
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• pp.153-174
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• 2016

On account of multiple causes, including prolonged global economic crisis, addressing environmental pollution and the advent of hyper-connected society, a new paradigm called 'sharing economy' has rapidly emerged. Many startups have attempted to build promising business model based on the sharing economy concept. Nevertheless, successful cases are still very rare in the global level, except for Uber and Airbnb cases. Therefore, this study analyzes necessary causes and sufficient causes for successful settlements in the market through a comparative case analysis on digital matching firms in the sharing economy businesses. For the case study, we compare five successful cases (Uber, Airbnb, Kickstarter, TaskRabbit and DogVacay), three failure cases (Homejoy, Ridejoy and Tuterspree) and a platform cooperativism case (Juno) in accordance with six value attributes of business model including value proposition, market segment, value chain, cost structure and profit potential, value network and competitive strategy. We apply Boolean method to support controlled comparison and eliminate unnecessary attributes. The Boolean analysis result shows that value proposition, cost structure and profit potential, value network and competitive strategy are the essential attributes. Furthermore, the result indicates that each attribute is a necessary condition, where all four conditions should be met simultaneously in order to be successful. With this result, we discuss essential consideration for those who are planning startup based on the sharing economy business model.

• Asian Journal of Business Environment
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• v.5 no.4
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• pp.37-46
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• 2015

Purpose - The present study examines interrelationships among antecedent factors defining consumer behavior in selecting online shopping websites. Research design, data, and methodology - The study identified factors from existing literature and used Interpretive Structural Modeling (ISM) to propose a conceptual approach to explain consumer website selection behavior. Through extensive discussions among industry and academia experts, qualitative assessment of the relationship between various factors was determined. Results - According to the model, eight congregating factors do not converge directly for website selection, rather, they operate following a hierarchy of influence. The ISM and MICMAC analysis reveal that information on a website and website aesthetics play key roles in influencing website selection. However, convenience and the value proposition also play very significant roles. Conclusions - The study's findings can help the e-commerce industry, especially online retailers. The findings can be used to enhance e-retailer ability to attract, communicate, engage, achieve, monitor, and evaluate web traffic and design appropriate strategies. The study's prime contribution is the application of Interpretative Structural Modeling (ISM) to the field of website selection.

• Journal of Korean Society for Quality Management
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• v.46 no.4
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• pp.797-820
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• 2018

Purpose: It is to seek for an appropriate cost rate analysis methodology of credit card value propositions in Korea. For this issue, it is claimed that methodologies based on probability distribution is more suitable than methodologies based on data-mining. The analysis model constructed for the cost rate estimation is called VCPM model. Methods: The model includes two major variables denoted as S and P. S is monthly credit card usage amount. P stands for the proportion of usage amount at special merchants over the whole monthly usage amount. The distributions assumed for P are positively skewed distributions such as exponential, gamma and lognormal. The major inputs to the model are also derived from S and P, which are E(S) and the aggregate proportion of usage amount at special merchants over the total monthly usage amount. Results: When the credit card's value proposition is general discount, the VCPM model fits well and generates reasonable cost rate(denoted as R). However, it seems that the model does not work well for other types of credit cards. Conclusion: The VCPM model is reliable for calculating cost rate for credit cards with positively skewed distribution of P, which are general discount card. However, another model should be built for cards with other types of distributions of P.