• Journal of The Korean Association For Science Education
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• v.25 no.3
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• pp.400-410
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• 2005

According to the cognitive conflict process model, student anxiety factor is known to have both positive and negative effects on student response behaviors in a conflict situation for conceptual change learning. However, there is little research that reveals what type of anxiety, either constructive or destructive, is related when conducting step-by-step experiments to resolve cognitive conflicts. This study attempted to learn the characteristic of explanatory hypothesis according to anxiety type after conducting five step-by-step experiments related to action and reaction concept. Results found that students who belonged to the types of 'conviction in logical misconception', 'insisting on additional variables', and 'reasonable modification' suggested explanatory hypothesis close to physical nature. On the other hand, those who showed the other five types of anxiety ('compatible predictions', 'dependence on others', 'fusion of past experience', 'lack of confidence', and 'conflict with past experience') suggested temporary supported hypothesis or simple explanatory hypothesis according to student intuition and simple observation. These results indicate that students in the above-mentioned five categories need more external interactions with instructors based on the type of anxiety related to student behavior. In addition, the results present student characteristics which instructors should be more attentive to when using step-by-step experiments to resolve cognitive conflicts.

• Journal of the Korean association of regional geographers
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• v.22 no.1
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• pp.120-134
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• 2016

This study aims to investigate the hierarchical stepwise migration and its influences on regions (metropolitan areas, cities and counties of Korea administrative district) through analyzing the city rank-size and the changes of natural increase of population. The result shows that the inter-regional migration has been associated to the decrease of the population and the decline of NIR in the regions where outflows have been persisted. Also, theses demographic events have sequentially occurred through the hierarchy of settlement system: gradually from rural (gun) and lower ranked regions in the system of city rank-size, to urban (si) and regions in the high ranks in the system. Based on the result of this study, it is possible to understand and expect the major origins of inter-regional migration, the presence of the hierarchical stepwise migration and most significantly, the spatial expansion of depopulation problems.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.5
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• pp.109-122
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• 1993

ln this paper, a finite element analysis procedure is proposed for the incremental multi-step excavations in a fluid-saturated porous medium such as saturated soil ground. As the basis of derivation, Biot's equation was used. The proposed procedure was applied to some one- and two-dimensional problems under incremental excavations. Unsaturated cases as well as saturated cases were considered for comparison. Through numerical tests, the effects of permeability and excavation speed on the deformation history was investigated. Results showed that pore pressure built up during incremental excavation has a significant effect on the deformation and stresses of solid skeleton and validated the use of the present procedure for the analysis of multi-step excavations in fluid-saturated media such as in saturated shallow ground.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.10a
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• pp.391-392
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• 2016

• Journal of the Korean Vacuum Society
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• v.12 no.1
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• pp.51-54
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• 2003

The spontaneous oscillations in the optogalvanic signals are observed in negative glow region of Ar hollow cathode discharge. The spontaneous oscillations in the optogalvanic signals are observed at low discharge currents less than about 3 mA. Based on the simultaneous measurements of both the density variation of metastable atoms and emission intensities of the 1s-2p transitions, one of the possible mechanisms for the spontaneous oscillation is considered to be related to the stepwise ionization of the metastable atoms due to collisions with slow electrons in the discharge.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.134-136
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• 2014

현대시대에 변화하는 정보사회에서 정보자원의 폭발적인 증가에 따른 빅 데이터 시대의 도래와 함께, 빅 데이터의 사용을 좀 더 효과적으로 사용하기 위하여 클라우드 컴퓨팅 방식의 관심이 높아지고 있다. 클라우드 컴퓨팅이란 어느 하나의 대형 서버에 소프트웨어나 데이터가 저장되는 것이 아니라 네트워크로 연결되어 마치 구름처럼 고정된 형태가 없는 가상 세계의 서버에 저장된다는 의미이다 본 논문에서는 정보자원의 효과적인 관리 및 처리를 위해서 기존시스템에 클라우드 컴퓨팅 도입하기 위한 단계적 접근방법을 제안한다.

• Fire Science and Engineering
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• v.29 no.3
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• pp.13-20
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• 2015

As building height is increased, more careful decisions about the required safe egress time is needed for evacuation. This study analyzed the influence of three training sessions on the vertical speed of evacuation in the high rise building. Evacuation experiments were done in a high-rise office building in Seoul, and we analyzed the vertical evacuation speed as a function of density using a camera. Controlled and uncontrolled total evacuation were compared using the Pathfinder simulation. The process of repeated training, changed the specific stair utilization rate from 6.3% to 39.5%. The vertical evacuation speed as a function of density was analyzed using the equation s = 1.004 ? 0.288D, which is very similar to the equation used in a different study. The total evacuation time of the special controlled total evacuation was reduced by about 25% compared to the simultaneous evacuation.

• Journal of the Korean Society for Library and Information Science
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• v.51 no.4
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• pp.161-181
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• 2017

The present study aimed at investigating health information seeking behaviors of health information consumers who changed their health behaviors by using mobile health applications according to the dynamic stages of change. For this purpose, the study analyzed the changes of perception, health information needs and seeking behaviors of health information consumers in each stage by employing Stages of Change as a theoretical framework. A total of 30 college students participated in this study to change health behaviors such as smoking or alcohol cessation, and regular exercise, while using health applications for 3 months; then written interviews were conducted with these students based on their experiences. Findings indicated that the study participants used diverse information sources, including social media and the Internet, seeking for different types of sources of information according to information needs. Above all, the health information needs and seeking behaviors examined in active utilization of health applications by consumers in the stage of action suggest the implications of health information services, particularly through health applications. In addition, stress management and relapse that consumers experienced while attempting health behavior changes, and the positive and negative effects of behavior changes inform health information providers of insights for supporting consumers' changes of health behaviors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.1
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• pp.111-119
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• 1994

In this paper we propose a reversible image coding methods with progressive build-up function by bit-plane of multi-lavel image. Firstly, the differencial conversion is applied to reduce the entropy of source images. Then the bit-plane sequences of converted images are coded by means of the newly designed VFRL(Variable to Fixed Run-Llength) code and the RDHC(Run-length Dynamic Huffman Coding). We aim to the simple construction to reduce the complexity. The computer simulated results show that the proposed methods are very effective to the multi-level digital images. For "GIRL" and "COUPLE" of 1EEE monochromatic standard images, the compressibility are superior to the results obtained by the well-known universal codes.own universal codes.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.513-516
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• 2007

인터넷상의 정보가 빠르게 변화함에 따라 정보의 최신성을 유지하며 웹 상의 정보를 통합하기 위한 실시간 웹 통합 방법들이 제안되고 있다. 하지만 대부분이 실시간 추출에 소요되는 시간이 너무 긴 단점을 가진다. 본 논문에서는 추출시간을 줄이기 위해 입력 질의를 분리하여 사용자와 상호작용하며 단계적으로 웹 통합을 수행하는 방법을 제안한다. 실험을 통해 기존 방식과 응답시간을 비교하여 유용성을 확인하였다.