• School Mathematics
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• v.12 no.4
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• pp.455-471
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• 2010

Understanding of randomness is essential for learning and teaching of probability and statistics. Understanding of randomness prompts to understand natural and social phenomena from the point of view of mathematics, and plays a role of base in understanding of judgments based on rational interpretation on these phenomena. This study examined whether pre-service teachers recognize this, and they understand randomness included in various contexts. According to results, they did not have a understanding of randomness in the context related to measuring, while they grasped randomness in simple and joint events. This implies that they lack the understanding of variability which is essential in the context of measuring. This study, therefore, suggests that the settings of measuring should be introduced into probability and statistics education, especially that data from measuring should be analyzed focusing on the variability in the data set.

• Journal of Korea Technology Innovation Society
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• v.13 no.2
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• pp.310-331
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• 2010

Recently, US, EU and major development countries, including Korea, have set green growth strategy the for national robust economic growth. Green growth strategy was also adopted as economic stimulus policy. Korea also have established some policies for green growth such as Green Growth National Strategy and 5-years Plan. Thought the SMEs play an important role as the innovative driver that can supply material and components for final products, there are few policies for joining green growth strategy. So, the purpose of this paper is to explore the current extent of public procurement for technology-development products and propose the betterment of it. Firstly, we analyzed the public procurement-policies of major countries to kinds of policy-purposes and types including Korea. and then we deducted the needs to policy utilizing the public procurement for joining the SMEs to green growth strategy. Second, we proposed that the objects of purchase conditional public procurement policy be extent to the pre-commercial technologies. The pre-commercial technologies could be performed further R&D by some other compaines or pubic institutes. Considering the natures of green technology-such as quasi-public-, this improvement would be helpful for SMEs which could create initial-marketplace and sales-references.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.115-121
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• 2008

A core engine for pre-cooled turbojet engines is designed and its component performances are examined both by CFD analyses and experiments. The engine is designed for a flight demonstration of precooled turbojet engine cycle. The engine uses gas hydrogen as fuel. The external boundary including measurement devices is set within $23cm{\times}23cm$ of rectangular cross section, in order to install the engine downstream of the air intake. The rotation speed is 80000 rpm at design point. Mixed flow compressor is selected to attain high pressure ratio and small diameter by single stage. Reverse type main combustor is selected to reduce the engine diameter and the rotating shaft length. The temperature at main combustor is determined by the temperature limit of non-cooled turbine. High loading turbine is designed to attain high pressure ratio by single stage. The firing test of the core engine is conducted using components of small pre-cooled turbojet engine. Gas hydrogen is injected into the main burner and hot gas is generated to drive the turbine. Air flow rate of the compressor can be modulated by a variable geometry exhaust nozzle, which is connected downstream of the core engine. As a result, 75% rotation speed is attained without hazardous vibration and heat damage. Aerodynamic performances of both compressor and turbine are obtained and evaluated independently.

• Journal of KIBIM
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• v.11 no.1
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• pp.21-30
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• 2021

Reinforcing bars, a major component of the pre-fab structure, adheres to the existing on-site assembly method and attempts to develop and commercialize the technology of the pre-assembly method, but the effect is insignificant. Welded Wire / Bar Mat (WBM) has various advantages such as commercialization of rebar through machine manufacturing to improve workability, but it is different from the existing design and the construction method is different from the previous one. Therefore, to maximize the advantages of WBM and improve productivity, manufacturing, transportation, and construction from the design stage should be considered based on BIM from the initial design stage. In this paper, the concept of the design support system for the WBM was established based on the use of BIM in concrete reinforcement and the preliminary research on the WBM. WBM conversion design was performed for the existing prefabricated members, and based on this, the exchange format and system of the master prefabricated model with the WBM design data were set up. As a result of the pilot test, it was found that the traditional reinforcing bar information extracted from the master prefab model has transmitted 100% accurately. As for the WBM information, 100% of the information on the straight reinforcement was transmitted and represented, and the information on the bent reinforcement was found to have a 90% recall in the master BIM tool.

• The Journal of Korean Physical Therapy
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• v.33 no.6
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• pp.272-277
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• 2021

Purpose: The purpose of this study is to confirm the effect of static stretching of the plantar flexor for 5 minutes on balance and ankle muscle activity when walking in young adults. Methods: This study experimented on 20 healthy college students without vestibular and musculoskeletal diseases. Subjects performed static stretching intervention of plantar flexor for 5 minutes on a stretch board set at 15° to 25° Balance was measured four times before intervention (pre), after intervention (post), 5 minutes after intervention (post 5 min), 10 minutes after intervention (post 10 min), and ankle muscle activity was measured during walking. For the analysis and post hoc analysis, one-way Repeated Measure ANOVA and Fisher's LSD (Last Significant Difference) was performed to find out the change in balance and the activity of ankle muscles before static stretching, pre, post, post 5 minutes rest, post 10 minutes rest. Results: There was no significant difference in weight distribution index (WDI) in balance, but stability index (ST) showed a significant difference, and there was also a significant difference in correlation pre, post, post 5min rest, post 10 minutes rest (p<0.05). There was no significant difference in ankle muscle activity during walking in Tibialis anterior (TA), Medial gastrocnemius (GM), and Lateral gastrocnemius (GL) (p>0.05). Conclusion: The stability index (ST) increased significantly immediately after static stretching and decreased after 5 minutes. After static stretching, at least 5 minutes of rest are required to restore balance.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.4
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• pp.77-83
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• 2021

PURPOSE: This study examined the changes in the respiratory function when PNF chopping and lifting patterns were used in chronic stroke patients METHOD: The subjects were 30 patients diagnosed with chronic stroke. The respiratory function (FVC, FEV₁, and FEV₁/FVC) were measured by spirometry. Thirty subjects were divided randomly into an experimental group to which 15 PNF chopping and lifting were applied and a control group to which chest breathing exercise was performed. The intervention was conducted three times a week for six 6 weeks. To examine the effects of intervention, the pre- and post-intervention values for each group were compared using a paired t-test. An independent t-test was used to compare the differences in the values of changes pre- and post-intervention in the two groups. Statistical significance was set to .05. RESULTS: Satistically significant differences in FVC and FEV₁ were observed in both the experimental group and control group according to the intervention (p < .05). A statistically significant difference was found in FVC and FEV₁ compared to values of changes pre- and post-intervnetion between the experimental and control groups. There was no difference in FEV₁/FVC. CONCLUSION: The results suggest that PNF chopping and lifting can be applied as an excellent respiratory intervention program compared to general chest breathing exercises to improve respiratory function in stroke patients.

• Human Ecology Research
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• v.61 no.3
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• pp.361-373
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• 2023

The purpose of this study is to develop and apply a teaching-learning plan of apartment house class to improve middle school students' empathy for home economics education and to verify its effect. The study was conducted in five stages: analysis, design, development, implementation, and evaluation using the ADDIE model. In the analysis phase, the study set learning objectives after analyzing how community housing is dealt with in the 2015 revised home economics curriculum and 12 current technology and home economics textbooks. In the design and development stage, in order to evaluate the validity of the experts and to improve the empathy ability, the study goal design, the composition of the learning elements, the development of the learning materials, and the pre and post-questionnaire for the students were developed. In the implementation stage, the empathic ability evaluation was carried out before and after the beginning of the first class by applying the teaching-learning process plan of the 8th class. In the evaluation stage, we examined whether the teaching-learning process developed in this study has a significant effect on empathy ability by evaluating the pre-post difference of empathy ability. As a result of examining the results of the pre - and post - evaluation of empathy ability for the results of this study, both cognitive and communicative factors were improved, and the apartment house class had a significant effect on the improvement of empathy ability.

• Journal of the Korea Society of Computer and Information
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• v.28 no.9
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• pp.35-46
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• 2023

In this study, we propose a Dual Approach methodology to enhance the accuracy of document classifiers by utilizing both contextual and keyword information. Firstly, contextual information is extracted using Google's BERT, a pre-trained language model known for its outstanding performance in various natural language understanding tasks. Specifically, we employ KoBERT, a pre-trained model on the Korean corpus, to extract contextual information in the form of the CLS token. Secondly, keyword information is generated for each document by encoding the set of keywords into a single vector using an Autoencoder. We applied the proposed approach to 40,130 documents related to healthcare and medicine from the National R&D Projects database of the National Science and Technology Information Service (NTIS). The experimental results demonstrate that the proposed methodology outperforms existing methods that rely solely on document or word information in terms of accuracy for document classification.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.3
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• pp.98-107
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• 2007

For high-dimensional pattern recognition, such as face classification, the small number of training samples leads to the Small Sample Size problem when the number of pattern samples is smaller than the number of dimensionality. Recently, various LDA-extensions have been developed, including LDA, PCA+LDA, and Direct-LDA, to address the problem. This paper proposes a method of improving the classification efficiency by increasing the number of (sub)-classes through pre-clustering a training set prior to the execution of Direct-LDA. In LDA (or Direct-LDA), since the number of classes of the training set puts a limit to the dimensionality to be reduced, it is increased to the number of sub-classes that is obtained through clustering so that the classification performance of LDA-extensions can be improved. In other words, the eigen space of the training set consists of the range space and the null space, and the dimensionality of the range space increases as the number of classes increases. Therefore, when constructing the transformation matrix, through minimizing the null space, the loss of discriminatve information resulted from this space can be minimized. Experimental results for the artificial data of X-OR samples as well as the bench mark face databases of AT&T and Yale demonstrate that the classification efficiency of the proposed method could be improved.

• Journal of the Korea Computer Graphics Society
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• v.16 no.4
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• pp.25-33
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• 2010

With the popularization of digital photography, people are now capturing and storing far more photos than ever before. However, the enormous number of photos often discourages the users to identify desired photos. In this paper, we present a novel method for fast and intuitive browsing through large collections of geo-referenced photographs. Given a set of photos, we construct a hierarchical structure of clusters such that each cluster includes a set of spatially adjacent photos and its sub-clusters divide the photo set disjointly. For each cluster, we pre-compute its convex hull and the corresponding polygon area. At run-time, this pre-computed data allows us to efficiently visualize only a fraction of the clusters that are inside the current view and have easily recognizable sizes with respect to the current zoom level. Each cluster is displayed as a single polygon representing its convex hull instead of every photo location included in the cluster. The users can quickly transfer from clusters to clusters by simply selecting any interesting clusters. Our system automatically pans and zooms the view until the currently selected cluster fits precisely into the view with a moderate size. Our user study demonstrates that these new visualization and interaction techniques can significantly improve the capability of navigating over large collections of geo-referenced photos.