• 컴퓨터교육학회논문지
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• 제12권3호
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• pp.53-62
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• 2009

정보통신 기술의 발달로 다양한 교수매체가 등장함에 따라 교수매체에 적합한 콘텐츠 제공이 학습의 중요한 요소로 주목받고 있는 가운데, 특히 PDA와 같은 이동통신 학습 환경에 대한 학습자 요구가 꾸준히 증가하고 있다. 본 논문은 초등학생들의 수학 학습(사칙연산)을 보조하기 위한 이동 학습단말기로서의 PDA 매체를 이용한 학습콘텐츠 설계 기법, 즉 학습 콘텐츠 내에서의 학습 시퀀싱 모델과 학습 콘텐츠사이의 학습 시퀀싱 모델을 설계하였다. 그리고 이를 PDA에서 구현하고, 이를 지원해주는 학습운영시스템을 설계하고 개발하였다. 또한 PDA를 학습 보조 단말기로 활용할 수 있는 실질적인 학습 서비스를 구현하였다. 대한 요약을 기술하시면 됩니다.

• Advances in concrete construction
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• 제11권5호
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• pp.419-428
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• 2021

The pH of cement-based materials (CBMs) is an important factor for their durability, sustainability, and long service life. Currently, the use of supplementary cementitious materials (SCMs) is becoming mandatory due to economic, environmental, and sustainable issues. There is a decreasing trend in pH of CBMs due to incorporation of SCMs. The determination of numerical values of pH is very important for various low and high volume SCMs blended cement mortars for the better understanding of different defects and durability issues during their service life. In addition, the effect of cement hydration and pozzolanic reaction of SCMs on the pH should be determined at initial and later ages. In this study, the effect of low and high-volume fly ash (FA) and ground granulated ballast furnace slag (GGBFS) cement mortars in different curing conditions on their pH values has been determined. Thermal gravimetric analysis (TGA) was carried out to support the findings from pH measurements. In addition, thermal conductivity (k-value) and strength activity indices of these cement mortars were discussed. The results showed that pH values of all blended cement mortars were less than ordinary Portland cement (OPC) mortar in all curing conditions used. There was a decreasing tendency in pH of all mortars with passage of time. In addition, the pH of cement mortars was not only dependent on the quantity of Ca(OH)₂. The effect of adding SCMs on the pH value of cement mortar should be monitored and measured for both short and long terms.

• 한국실내디자인학회논문집
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• 제15권2호
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• pp.108-117
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• 2006

This study is to promote barrier-free environment to accommodate the request and the need for accessibility and convenience of disabled people including pregnant women, children and the elderly in using civic service offices which are supposed to play a role as community centers. This study researches the current state of facilities for convenience and analyzes the result according to the type of reasons which prevent disabled persons to get the accessibility and convenience for the information as well as the facilities. Sample cases are 15 civic service offices which are newly built after 1998 in the city of Daegu. There are found three types of problems about convenient facilities, which are the first cases with facilities not installed, the second cases with facilities not properly installed according to the rule, and the third cases with facilities installed properly according to the rule but inconvenient for the actual use. This study proposes a more critical process for the building permit to promote the rate of proper installation of convenience facilities, and the supplementary law with more specific regulations to improve the physical environment for the actual use of physically disabled people.

• 대한인간공학회지
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• 제31권1호
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• pp.211-217
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• 2012

Objective: The aim of this study is to show a correct application procedure using the compact Korean anthropometric data application program called Korean Human Scale(KHS) for anthropometric design. Background: The nation-wide anthropometric survey project called 'Size Korea' developed KHS and distributed it to the public on the web site. But some insufficiency of the current web service of KHS misleads the users; they just put their own statue and pick up a meaningless data for a body dimension. Method: This study provides five steps to follow to read appropriate data from KHS for an anthropometric design. Results: As a case study, the depth dimension of the supervisory and control console used in the Korea nuclear power plant was determined following the procedure and compared with the console design guideline recommendation. Conclusion: The supplementary anthropometry table should be added on the web service of KHS for users to read a meaningful data for design. Application: If properly used, the KHS has a lot more potential application area than users can expect such as in control center design area.

• Journal of the Korean Statistical Society
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• 제31권4호
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• pp.491-507
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• 2002

We analyze a single server bulk input queue with optional server vacations under a single vacation policy and balking phenomenon. The service times of the customers as well as the vacation times of the server have been assumed to be arbitrary (general). We further assume that not all arriving batches join the system during server's vacation periods. The supplementary variable technique is employed to obtain time-dependent probability generating functions of the queue size as well as the system size in terms of their Laplace transforms. For the steady state, we obtain probability generating functions of the queue size as well as the system size, the expected number of customers and the expected waiting time of the customers in the queue as well as the system, all in explicit and closed forms. Some special cases are discussed and some known results have been derived.

• International Journal of Contents
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• 제5권3호
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• pp.40-49
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• 2009

While numerous studies have suggested the significance of uncertainty during the process of information-seeking, less research has investigated user uncertainty in the actual search process using a real system. This study investigated user perceptions of uncertainty in the process of the selection of information retrieval system in the real information-seeking process. Considering the role of commercial Web search engines as supplementary tools for traditional bibliographic databases in academic research environments, this study analyzed the selection behavior of scholarly researchers, who use such search tools for their academic study. The researchers were limited to the discipline of science in order to understand user perceptions in this field. The findings revealed various dimensions, types, and incidents of uncertainty. Variations appeared in different incidents of uncertainty relating to the unique characteristics of the subjects' information-seeking context. The identification of three principal origins of uncertainty based on the different types of uncertainty generated implications to improve information systems and services.

• 한국가정과교육학회지
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• 제18권2호
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• pp.47-62
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• 2006

이 연구는 교육서비스 가격에 초점을 맞춤으로써 기존의 교육비 지출규모에 초점을 맞춘 선행연구들과 접목시켜 교육비 과다지출의 원인 및 개선에 기초 자료를 제공하고자 수행하였다. 분석기간은 15년(1990-2004)이며 자료는 물가연보이다. 첫째, 15년간(1990-2004)의 소비지출 비목의 물가 중에서 교육서비스 가격이 연평균 7.3%로 가장 높게 상승하였다. 납입금가격은 연평균 7.5%, 기타교육은 6.0%상승하였다. 둘째, 납입금가격은 전문대납입금, 유치원납입금, 사립대학납입금, 국공립대학납입금, 중고교납입금 순으로 상승하였다. 기타교육 서비스 가격은 초등교과서, 중학교교과서, 중학교참고서, 가정학습지 순으로 높게 나타났다. 셋째, 중고교의 교육서비스 가격을 16개 지역별로 분석한 결과, 중고교교과서, 중학교 참고서, 고교참고서는 지역에 따른 차이가 없었다. 단과입시학원에서는 광주시가 가장 많이 상승하였고 서울시가 가장 적게 상승하였다. 연평균 상승률의 지역별 차이는 7%정도였다. 2000년을 100으로 가정 할 때 광주 80%, 강원 57%로 가장 많이 상승하였다. 종합입시학원에서는 전남이 가장 많이 상승하였고 경북이 가장 적게 상승하였다. 대체로 지역별로 차이가 많은 것으로 나타났다. 연평균 상승률의 차이는 7%정도였다. 2000년을 100으로 가정 할 때 부산과 경남이 37%, 제주도 34%로 가장 많이 상승하였다.

• Journal of Korea Trade
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• 제25권5호
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• pp.19-38
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• 2021

Purpose - This study aims to verify the direct causal relationship between cost competitiveness and global network competitiveness, which are the tangible service quality factors determined by the shipping company, which in turn affect the shipper's customer satisfaction. Additionally, we empirically investigate the intangible, related service qualities determined by shipping companies, such as operational competitiveness and customer relationship quality, and how these then positively affect customer satisfaction through the formation of trust. Therefore, we examine the mediating effect of trust formation among different contractors for shipping services. Design/methodology - In order to examine the shipping company's tangible and intangible service-qualities perceived by the shipper on customer satisfaction and the process of trust formation between contractors, we collected valid data from 114 respondents out of 200 distributed questionnaires. The respondents consisted of domestic freight forwarders who engage with domestic and international shipping and logistics agencies. Descriptive statistics, confirmatory factor analysis, reliability, convergent and discriminant validities, common method bias, and PLS-SEM (partial least square-structural equation model) were analyzed using the program STATA 16. Findings - The findings of this study are as follows. First, our results showed that all hypotheses assumed in this study had statistically significant supporting evidence. Second, it was found that the mediating effect of trust was significant in affecting the quality of intangible service- qualities for customer satisfaction. Third, through supplementary analysis, we found that the global network competitiveness of domestic shipping companies will increase in importance in the future. In conclusion, the theoretical and practical implications of these findings are presented. Originality/value - This study reaffirmed the traditional causal relationship between customer satisfaction and tangible service quality. Additionally, we also contribute to the literature on the understanding of the causal relationship between trust formation and customer satisfaction through intangible interactions from a long-term perspective.

• Computers and Concrete
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• 제10권4호
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• pp.391-407
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• 2012

Utilization of supplementary cementing materials (SCM) by the cement industry, as a highly promising solution of sustainable cement development aiming to reduce carbon dioxide emissions, necessitates a more thorough evaluation of these types of materials on concrete durability. In this study a comparative assessment of the effect of SCM on concrete durability, of every cement type as defined in the European Standard EN 197-1 is taking place, using a software tool, based on proven predictive models (according to performance-related methods for assessing durability) developed and wide-validated for the estimation of concrete service life when designing for durability under harsh environments. The effect of Type II additives (fly ash, silica fume) on CEM I type of cement, as well as the effect of every Portland-composite type of cement (and others) are evaluated in terms of their performance in carbonation and chloride exposure, for a service life of 50 years. The main aim is to portray a unified and comprehensive evaluation of the efficiency of SCM in order to create the basis for future consideration of more types of cement to enter the production line in industry.

• 한국융합학회논문지
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• 제3권3호
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• pp.7-12
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• 2012

mVoIP 서비스는 IP 네트워크를 이용하여 모바일 장비에서 음성 정보를 보다 효율적으로 전송할 수 있는 기술이다. mVoIP 서비스는 적은 통신 비용으로도 다양한 부가서비스를 제공할 수 있으며, IP 기반 네트워크를 이용하여 효율성과 가용성을 높일 수 있는 방식이다. 또한 일반 사용자는 시간과 장소에 상관없이 모바일 장비에서 음성대화 서비스를 이용할 수 있다는 장점이 있다. 하지만, 모바일 장비에서의 SIP 프로토콜은 도청, DoS 공격 및 오작동, 스? 공격 등과 같은 다양한 공격과 위협에 노출되어 있어 많은 문제점으로 대두되고 있다. 이에 본 연구에서는 기존 mVoIP 서비스에 대한 위협과 취약성에 대해 분석하여 다양한 형태의 공격 시나리오를 도출하였다. 공격 시나리오에 대한 보안 취약성을 분석하여 보다 안전한 SIP 메커니즘을 제시하였으며 모바일 환경에서의 취약성을 제거할 수 있는 대응 방안을 제시하였다.