• Journal of Chest Surgery
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• v.37 no.2
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• pp.146-153
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• 2004

As the experience of coronary artery bypass grafting (CABG) has been accumulated, the number of reoperation after CABG is increasing. We analyzed our clinical experience of redo-CABG. Material and Method: Fourteen patients who underwent redo-CABG between Jan. 1994 and Dec. 2002 were included in this study. The mean period from the first operation to reoperation was 66$\pm$56 (3∼157) months, and the average ages were 62.8$\pm$8.7 (51∼78) years. The survivors were followed up 39$\pm$29 (4∼101) months postoperatively. Indications of reoperation were stenosis or occlusion of previous grafts in 11 patients, progression of native coronary artery disease in one patient, and both etiologies in two patients. Result: There were two in-hospital mortalities (14.3%) resulting from low cardiac output syndrome, Postoperative morbidities were perioperative myocardiac infarction in 2 patients (14.3%), mediastinitis in one patient (7.2%), duodenal perforation in one patient, ischemic necrosis of the lower extremity in one patient, gastric perforation after mesenteric infarct in one patient, delayed brain infarct in one patient, and intraoperative splenic rupture in one patient. There was one late mortality at six months postoperatively during the follow up. There was no angina recurrence during the follow up. Conclusion: Although redo CABG demonstrated relatively high operative mortalities and morbidities, postoperative status and clinical outcome of the survivors were favorable.

• Journal of The Korean Association For Science Education
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• v.26 no.3
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• pp.356-366
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• 2006

The purpose of this study was to investigate the effects of offering similar experiences for hypothesis-generation based on abduction. Two hundred and seventy eight students in Seoul(8th and 10th grades) were requested to propose causal questions and generate hypotheses after observing an unfamiliar situation. Then, after having been presented numerous similar experimental situations to initial situation, the students were asked to regenerate a hypothesis. When the $X^2$ analysis was done to determine differences in hypothesis generation before and after offering the similar experimental situations, a meaningful difference appeared(p<.001). This study proposes that offering similar experimental situations ease hypothesis-generation based on abductive reasoning. Additionally, the second meaningful difference was discovered when the $X^2$ analysis was carried out to find differences in causal question proposal and hypothesis generation among students who had varied cognitive levels(p<.05) Considering the findings of the study, a progressive stage offering similar scenarios may further abductive reasoning while implementing lessons related to hypothesis generation in middle and high school.

• Journal of the Korean Data and Information Science Society
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• v.8 no.1
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• pp.21-30
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• 1997

In accelerated life tests, the failure time of an item is observed under a high stress level, and based on the time the performances of items are investigated at the normal stress level. In this paper, when the mean of the prior of a failure rate is known in the exponential lifetime distribution with censored accelerated failure time data, we utilize the empirical Bayesian method by using the moment estimators in order to estimate the parameters of the prior distribution and obtain the empirical Bayesian predictive density and predictive intervals for a future observation under the normal stress level.

• Journal of the Korean School Mathematics Society
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• v.10 no.2
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• pp.207-219
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• 2007

Students have a hard time with a formal proof, which is one of most important part in mathematics education. They were taught the proof with algebraic visual materials using technology and specialized visual materials. But, they experienced the difficulty in justifying due to the lack of experimental recognition with the representation using technology. The specialized visual materials limited the extension of mathematics thinking of students because it worked only for the case that is fixed. In order to solve this type of problem, we made algebraic visual materials for 9th graders using technology and generalized visual materials so that students experience for themselves to help them to experience experimental justification, thus we recognized that they were improved in enhancing mathematical thinking.

• Archives of design research
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• v.17 no.2
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• pp.289-300
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• 2004

Recently, web casting on the internet has been expanding in number and size. Web Casting is different from the conventional television broadcasting since it can transmit various types of information through multimedia and it also can include interaction between users and broadcasting server. User experience by interaction becomes more important. Therefore, it is needed to win over customers by supplying satisfied experience through creative and different services, especially when there are consider competitions among music casting sites. In order to know how to make customers satisfied, we have to try to inspect what real customers in the Web Sites are acting and thinking, namely 'customer experience'. The 'customer experience' means every experience what users are expecting, doing, thinking and feeling when they stay in the Web site and online. In this thesis, the evaluation Guideline for music casting websites is developed by understanding customer experience on the music casting websites. The process of understanding customer experience was implemented through user observation methods, such as web Diary, group interview, and questionnaire. As a result of the study, 67 evaluation Guidelines with weight rate in 6 categories which are searching music, listening music, music video, music broadcasting, music mailing and other contents are developed. It can be used to analyze strengths and weakness of music casting sites and to establish business strategy for the more satisfied customer experience.

• Journal of the Korean Geographical Society
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• v.38 no.5
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• pp.802-821
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• 2003

This paper aims to illuminate how the Naturalists' concern on geography and geography education, mainly in Comenius, Rousseau, Pestalozzi who have played key roles in the development of Naturalism, has developed and how the Naturalism has influenced on the development of geography and geography education. Starting from sensual realism, the Naturalism suggested the educational principle and methods adjusting to the Nature well as exercised great influence on the formation of modem school education toward popular common education. The geography took the firm position as subject in the curriculum of the Naturalists and achieved the rationale of existence as subject in curriculum with utility to expand human experience, thanks to Naturalists. The Naturalists developed several ideas on geography teaching method such as labouring activity-centered geography teaching based on strengthening sense and experience by 'look-and-see' approach, local geography-centered geography teaching with stress the local area as the focus of direct experience and living environment, and the real thing-centered geography teaching by fieldwork. Moreover, The Naturalists had an great effect on the geographer, Karl Ritter in terms of methodology of geography.

• Journal of the Korean earth science society
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• v.34 no.1
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• pp.93-101
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• 2013

This study investigated how the unique educational contexts in the Republic of Korea (RK) impacted two science teachers' teaching practices in a public middle school and what the science teaching experience means to them. In particular, we explored how the middle school science teachers decide pedagogical approaches to use in their teaching based on classroom climate, students' attitude toward learning science, school curriculum and classroom culture. Using a phenomenological research approach, we analyzed classroom observation data and interview data to interpret the teachers' science teaching experience. Results of the study showed that the teachers' practice was dominantly affected by two external factors. First, the teachers' teaching practice was affected by the amount of science content knowledge they need to cover within a given class time. Second, the teachers' teaching practice was affected by students' attitudes toward science learning and their science preparedness in private tutoring centers. Implications of the study results are discussed in the paper.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.12 no.1
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• pp.38-45
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• 2018

The purpose of this study was to investigate the effects of an increase in self - determination experience on the behavior of young children with autism spectrum disorder by telepresence robot. As for research method, the study used AB design, two selected children engaged in activities with a telepresence robot in free play time in the morning. The activities were conducted in 19 sessions, twice a week, 15 to 40 minutes each. To investigate the effect of the activity on the child's behavior was observed using the behaviors of free play time and work time in the afternoon. All the process was recorded by a camera and then analyzed by frequency recording. The results of the study are as follows. First, the participation of young children with autism spectrum disorder in free play time increased. Second, choice-making or preference behavior of young children with autistic spectrum disorder were increased. This study suggests that increasing the self-determination experience of young children with autism spectrum disorders using telepresence robots increases their participation and increases their choice-making or preference behavior.

• Journal of the Korea Computer Graphics Society
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• v.27 no.5
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• pp.13-23
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• 2021

This study examined how users use smart speakers in cooking situations. Skilled and unskilled participants cooked a new recipe while following voice instructions delivered by a smart speaker. The results from video recordings of their cooking, think-aloud protocols, and interviews showed that the smart speakers freed users' hands, allowing them to cook while checking recipes. The lack of visual information did not pose a serious challenge to the cooking task, but impacted cooking quality. The implications for VUI-based recipe service designs are discussed.

• Journal of Digital Convergence
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• v.16 no.6
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• pp.325-333
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• 2018

The quality of indoor air quality is facing a very serious situation due to the impact of the quality of the atmosphere in the atmosphere and the surrounding environment. While awareness of the danger of these populations is increasing, there is no way to detect the quality of the indoor air quality as well as the measures to detect the quality of indoor air quality as well as the countermeasures. The study drew a general problem with the design of the service design, the general purpose of the general office, and the use of the public facilities for the purpose of measuring the usage of indoor air quality, the general purpose of public facilities, and the interpretation of the current law. Based on this research, most of the general users' perception of the seriousness of the disease is not reflected in the perception that the dust and indoor air are accumulated in the eyes of the general public.