• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.348-351
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• 2012

The effect of the addition of Cu on the catalytic activity of the $Mn/CeO_2-ZrO_2$ catalyst for the low-temperature SCR reaction of NO was investigated. Three different amounts of Cu, 5, 10, and 15 wt%, were impregnated on the $Mn/CeO_2-ZrO_2$ catalyst. The characteristics of the synthesized catalysts were examined by BET, XRD, XPS, and $H_2-TPR$ analyses. The de-NOx efficiency of the Cu-added catalysts increased with the amount of Cu. When 15 wt% Cu was impregnated, the deNOx efficiency was the highest, reaching as high as 99%. The increased deNOx efficiency is attributed to the enhanced reducing power stemming from the interaction between Mn and Cu on the catalyst surface.

• Journal of Korea Spatial Information System Society
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• v.7 no.2 s.14
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• pp.15-27
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• 2005

The purpose of this study is to present a methodology of GIS audit system which fully reflects standardization regarding GIS. With the recognition of the problems stemming from data exchange, building costs, and budget waste, this study utilized the standardization for evaluation factors of GIS audit. After analyzing the advantages and disadvantages of current audit methodology, this study pointed out the importance of audit, then presenting main audit factors followed by analyzing national standardization and extracting contents of audit to be added into the existing auditing items. Through the analysis of different types and characteristics, and both advantages and disadvantages of GASP, this study identifies and introduces a highly improved and practical methodology called Modified-GASP (M-GASP) that is basically set to be complementary and supplementary to GASP. Ultimately, the result of this study will support the higher degree of efficiency, stability, and extendability of GIS system, not to mention of strengthening the competitiveness of organizations involved.

• Journal of KIISE:Information Networking
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• v.32 no.6
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• pp.723-731
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• 2005

Wide spread deployment of infrastructure WLANs has made Wi Fi an integral part of today's Internet access technology. Despite its crucial role in affecting end to end performance, past research has focused on MAC protocol enhancement, analysis and simulation based performance evaluation without sufficient consideration for modeling inaccuracies stemming from inter layer dependencies, including physical layer diversity, that significantly impact performance. We take a fresh look at IEEE 802.11 WLANs, and using experiment, simulation, and analysis demonstrate its surprisingly agile performance traits. Contention based MAC throughput degrades gracefully under congested conditions, enabled by physical layer channel diversity that reduces the effective level of MAC contention. In contrast, fairness and jitter significantly degrade at a critical offered load. This duality obviates the need for link layer flow control for throughput improvement but necessitates traffic control for fairness and QoS. We use experimentation and simulation in a complementary fashion, pointing out performance characteristics where they agree and differ.

• School Mathematics
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• v.11 no.4
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• pp.723-743
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• 2009

This paper analyzed the main contents of multiplication and division of fractions in elementary mathematics textbooks and workbooks aligned to the national mathematics curriculum. This paper first explored the adequacy of when to teach the contents, the connection of instructional flow across grades, and the method of constructing a unit to teach multiplication or division of fractions. This paper then analyzed in detail the contents with regard to the types and frequency of word problems, the types of visual models and frequency, and the process of formalizing the calculation methods and principles. It is expected that the issues and suggestions stemming from this analysis of current textbooks and workbooks are informative in developing new instructional materials aligned to the recently revised mathematics curriculum.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.2
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• pp.74-81
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• 2002

In general, a multipath generator consists of a time delay generator, phase rotator, and amplitude attenuator, and is implemented mostly in an analog manner. Analog, or partially analog versions of a multipath generator is disadvantageous in that they may suffer from problems associated with component aging and adjustment, signal fidelity degradation stemming from repeated A/D and D/A conversion use of high frequency to achieve fine i.e., subsample fractional tin delays. This paper presents the design and implementation methodology of a full digital multipath generator which can be used in performance evaluations of digital terrestrial television as well as communications, receivers. In particular, an efficient practical method is proposed which can achieve both integer and fractional time delays simultaneously, without placing restrictions on the allowable system master clock frequency. The proposed algorithm lends itself to minimizing hardware implementation cost by relegating some fixed put of the computation involved to an IBM PC. The proposed multipath generator occupies only a single digital board space, and its experimental results are provided to corroborate the proposed implementation methodology.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.3
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• pp.35-46
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• 2016

Social network services (SNS) that help to build relationship network and share a particular interest or activity freely according to their interests by posting comments, photos, videos,${\ldots}$ on online communities such as blogs have adopted and developed widely as a social phenomenon. Several researches have been done to explore the pattern and valuable information in social networks data via text mining such as opinion mining and semantic analysis. For improving the efficiency of text mining, keyword-based approach have been applied but most of researchers argued the limitations of the rules of Korean orthography. This research aims to construct a database of non-standard Korean words which are difficulty in data mining such abbreviations, slangs, strange expressions, emoticons in order to improve the limitations in keyword-based text mining techniques. Based on the study of subjective opinions about specific topics on blogs, this research extracted non-standard words that were found useful in text mining process.

• Journal of Korean Library and Information Science Society
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• v.49 no.2
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• pp.179-199
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• 2018

The purpose of this study is to analyze the difference of economic condition of students, that is, the difference of basic information utilization ability stemming from education gap. First, we investigated information literacy for high school freshmen who can control the difference of information utilization education experience by school. In doing the research, 629 high school students in the metropolitan city were surveyed using web. we analyzed the educational gap between schools depending on their economic conditions and analyzed the correlation between education gap and basic information utilization ability. As a result, it was found that there is a very significant negative correlation between the ratio of students who get support for school expenses and basic information utilization ability. Second, regression equation was produced through regression analysis of information literacy regression to analyze the effect of educational gap on basic information literacy. In addition, it seeks to consider alternatives that can improve the inequality of information literacy which is derived from education gap.

• Korean Journal of Human Ecology
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• v.20 no.4
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• pp.731-743
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• 2011

The purpose of this study was to explore the relationship between personality differences and marital conflict. In particular, this study examined what impact, if any, exists between groups married for fewer than five years(Group 1) and those married for five or more years(Group 2). The sample consisted of 368 married couples. Each couple was asked to complete two questionnaires: one for measuring marital conflict and another for assessing husbands' and wives' personalities using the Myers-Briggs Type Indicator(MBTI). The results of this study were as follows: First, between Group 1 and Group 2, marital conflict showed no differences. Second, no marital conflict, caused by the four types of personality, was found in Group 2. However, for Group 1, the marital conflict perceived by wives was influenced by J-P and S-N types of wives, and the marital conflict perceived by husbands was affected by J-P type of husbands and S-N type of wives. Third, for Group 1, the marital conflict perceived by wives was influenced by the difference between S-N types. The marital conflict perceived by husbands was affected by differences between S-N types and between J-P types. No marital conflict, caused by the difference of the four types of personality, was found in Group 2. The results showed that the four types of personality and the differences in personality types between the couples affected marital conflict, depending on the duration of marriage. Therefore, it is important for the newly married couple to comprehend their spouse's personality and to adjust their lifestyles stemming from their personality differences.

• Korean Management Science Review
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• v.31 no.1
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• pp.1-15
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• 2014

As the scarcity of natural resources has become apparent, the recycling industry has emerged as a promising one for its growth potential. Yet, the recycling industry still remains undeveloped and inefficient for various reasons. In this study, we focus on firms' recycling processes to understand the current status of recycling firms' value creation activities. With respect to the adopted recycling processes, we empirically investigate the differences in firm characteristics and firm performance. We use the data from Keco (Korea Environment Cooperation) which annually conducts a survey of recycling firms in Korea. We exclusively consider the whole group of plastic recycling industry in order to control for a possible bias in firm performance, stemming from the heterogeneity in processing and recycling of materials other than plastics. We review the descriptive statistics from the sample firms and conduct a series of hierarchical regression analyses. The results show that most of the firms in this industry adopt physical transformation processes with a low-level technology. These firms with physical transformation processes are smaller in size and produce entry level items which do not secure higher margins. The results indicate that the recycling industry largely comprises low value added firms which lack economies of scale and resources for R&D. For the stable growth of the industry, recycling firms must create sustainable values through implementation of technology-driven processes and improvement in product quality. In addition, the government should help build a reliable reverse logistic network, lower the entry barriers, and provide necessary funding for the SMEs in the recycling industry.

• Journal of Digital Convergence
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• v.12 no.5
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• pp.367-376
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• 2014

This survey research investigates the relationship in adolescent attitudes toward sexual consciousness and intimate relationships according to their exposure to internet pornography. The results of the study indicated that 57.1% of the participants have experienced contact with internet pornography with most participants (48.7%) having first encountered internet pornography while in fourth, fifth or sixth grade. As students progress in school, their exposure to the internet increases thus increasing their potential to be exposed to pornography. Adolescents with no experience encountering internet pornography had a more positive attitude towards sexual consciousness, while adolescents with experience encountering pornography had more uninhibited libidos and were more open to romantic relationships. From the results above, there is a need for preventative measures against problematic behavior stemming from the influences of direct and indirect pornographic exposure on adolescent attitudes towards sexual consciousness and intimate relationships. Mental health services need to be provided for high risk adolescents addicted to pornography like mental health schools or help from specialists.