• Journal of Information Processing Systems
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• v.2 no.2
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• pp.67-75
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• 2006

In order to acquire a precise and quick response to an analytical query, proper selection of the views to materialize in the data warehouse is crucial. In traditional view selection algorithms, all relations are considered for selection as materialized views. However, materializing all relations rather than a part results in much worse performance in terms of time and space costs. Therefore, we present an improved algorithm for selection of views to materialize using the clustering method to overcome the problem resulting from conventional view selection algorithms. In the presented algorithm, ASVMRT (Algorithm for Selection of Views to Materialize using Reduced Table), we first generate reduced tables in the data warehouse using clustering based on attribute-values density, and then we consider the combination of reduced tables as materialized views instead of a combination of the original base relations. For the justification of the proposed algorithm, we reveal the experimental results in which both time and space costs are approximately 1.8 times better than conventional algorithms.

• Journal of Korean Elementary Science Education
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• v.24 no.5
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• pp.558-570
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• 2005

The importance of teaching the nature of science (NOS) has been always emphasized in science education. However, the NOS is hardly taught in elementary science class. We are lacking in the strategies and materials for teaching NOS. So we designed the science drama teaching, and investigated the effects on pupils' perceptions about NOS. The subjects of this study were 185 third graders from a elementary school. The treatment group was provided with science drama lessons and the control group was provided with traditional lecture-type lessons. Their perceptions about NOS were investigated before/after the science lessons and after 3 months following them, and both of two groups were compared. The pretest results revealed that the pupils of both groups were found to have similar views on NOS. Dey had traditional views of the most items except for social construction of theories, mathematical knowledge and decision-making. After science lessons, they tended to change their views toward modem views, but the pupils of the treatment group showed more modem views than those of the control group on the observation, model, social construction of theories, predictions. After 3 months, the pupils of the control group tended to come back to their traditional views, but those of the treatment group showed tendencies that their changed views were kept up on the observation, scientific model, scientific knowledge, scientific methods, decision-making, social construction of theories, mathematical knowledge. Therefore this study suggests that science drama teaching could be one of the effective ways for teaching NOS.

• Journal of the Korea Convergence Society
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• v.11 no.3
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• pp.153-162
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• 2020

This study was conducted to identify the factors that affect the views on marriage of male and female students. Of the students recruited, 172 were male, and 185 were female. Data were collected using questionnaires about views on marriage, children, gender roles, and gender attitudes and were analyzed using the IBM SPSS 23.0 program. Data were collected from May 1, 2019 to June 15, 2019. The significant predictors of views on marriage were views on children(F=29.530, p<.001), gender roles(F=9.850, p<.001) and gender attitudes(F=7.038 p=.009), explaining 33.4% of the variance in male, were views on children(F=48.767, p<.001), gender attitudes(F=32.204, p<.001) and gender roles(F=18.904, p<.001), explaining 43.8% of the variance in female. Therefore, it is necessary to develop programs to improve views on students.

• Journal of People, Plants, and Environment
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• v.24 no.5
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• pp.545-550
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• 2021

Background and objective: With increasing land use intensity in urban areas, apartment buildings have been recognized as a typical type of urban residence. In this study, the impacts of different views through a window on health-related responses were investigated using psychological and physiological parameters. Methods: Photos of three different types of views taken on low (2-12 m), middle (28-35 m), and high (over 54 m) floors of dense apartment building areas were used as visual stimuli. Twenty-two healthy adults participated in the indoor experiment. Semantic differential methods and profile of mood states were used as psychological tools. Autonomic nervous activity was evaluated using blood pressures, pulse rate and heart rate variability (HRV). Results: Analytic data showed different characteristics of psychological and physiological outcomes in three different apartment views. In the analysis of psychological parameters, significantly negative responses to the views on middle floors were found in the subscales of tension-anxiety and anger-hostility, compared to low floors. Significantly positive scores in the subscale of vigor were found on low floors with abundance of vegetation and high floors with a view of the sky. A significantly increased value of HF was found on low floors (2,294.96 ± 169.79), compared to the middle(1,553.45 ± 84.66) and high (1,523.02 ± 70.49) floors. Despite the high scores in openness and vigor, high floor views showed significantly higher LF/HF values (1.83 ± 0.09), the indicator of the sympathetic nervous system, than low (1.30 ± 0.07) and middle floor views (1.34 ± 0.06), which might be related to the unconscious fear of heights. Conclusion: Views from different heights in an apartment building can affect the psychological states of residents. Green space through the window may have a positive health outcome by reducing physiological stress.

• The KIPS Transactions:PartD
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• v.13D no.6 s.109
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• pp.797-806
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• 2006

In the data warehouse environment, materialized views are typically used to support efficient query processing. Materialized views need to be updated when source data change. Since the update of the views need impose a significant overhead, it is essential to update the views efficiently. Though various view maintenance strategies have been discussed in the past, the efficient maintenance of SPJ materialized views has not been sufficiently investigated. In this paper, we propose an efficient incremental view maintenance method for SPJ materialized views that minimizes the total accesses to data sources. The proposed method finds an optimal view maintenance strategy using a dynamic programming algorithm. We also present various experimental results that shows the efficiency of our proposed method.

• Journal of The Korean Association For Science Education
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• v.23 no.1
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• pp.9-20
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• 2003

In this study, elementary school students' views about nature were searched. The participants were 18 students of fifth grade and sixth grade. Data were collected via semi-structured interviews involving a set of elicitation devices used to encourage students to talk about their views about nature, The results showed as follows; (1) Elementary school students had diverse views and common views about nature, (2) Their views about nature were affected by various factors, such as religion, aesthetical aspect, science, society, and so on. So when science educators construct science curriculum, they must consider these factors. (3) It is necessary to be concerned about the relations between science curriculum and others.

• The KIPS Transactions:PartD
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• v.10D no.6
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• pp.917-926
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• 2003

More views in data warehouse, can respond to the users more rapidly because the user's requests may be processed by utilizing only the materialized views with higher probabilities rather than accessing base relations. But, more views cause longer update duration of all the materialized views. During the update time, queries of users can not be processed because accesses to the datawarehouse are blocked. Thus, the update durations of the materialized views are necessary to be reduced. In this paper, we propose algorithm the update duration of the materialized views owing to managing by distinguishing insecton/deletion operations. Though there might overheads for distinguishing insertion/deletion, we concluded that the proposed algorithm could be excellent than others.

• The KIPS Transactions:PartD
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• v.16D no.4
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• pp.463-474
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• 2009

To analyze multidimensional data conveniently and efficiently, OLAP (On-Line Analytical Processing) systems or e-business are widely using views in a horizontal form to represent measurement values over multiple dimensions. These views can be stored as materialized views derived from several sources in order to support accesses to the integrated data. The horizontal views can provide effective accesses to complex queries of OLAP or e-business. However, we have a problem of occurring maintenance of the horizontal views since data sources are distributed over remote sites. We need a method that propagates the changes of source tables to the corresponding horizontal views. In this paper, we address incremental maintenance of horizontal views that makes it possible to reflect the changes of source tables efficiently. We first propose an overall framework that processes queries over horizontal views transformed from source tables in a vertical form. Under the proposed framework, we propagate the change of vertical tables to the corresponding horizontal views. In order to execute this view maintenance process efficiently, we keep every change of vertical tables in a differential file and then modify the horizontal views with the differential file. Because the differential file is represented as a vertical form, its tuples should be converted to those in a horizontal form to apply them to the out-of-date horizontal view. With this mechanism, horizontal views can be efficiently refreshed with the changes in a differential file without accessing source tables. Experimental results show that the proposed method improves average performance by 1.2$\sim$5.0 times over the existing methods.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.12
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• pp.1825-1833
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• 1990

This paper proposes an efficient algorithm that constructs 3-dimensional solid object from 3 orthogonal views. This algorithm inputs vertex and edge information of 3 orthogonal views and generates 2 dimensional surfaces, 3 dimensional vertices, edges and surfaces and then compares 2 dimensional projections of 3 dimensional surfaces with surfaces from othorgonal views. This algorithm is useful for CAD system, 3 dimensional scene analysis system and object modeling for real-time animation and has been implemented in C language on IRIS workstation. The effectiveness of this algorithm is shown by examples of aircrafts' models.

• Journal of Gifted/Talented Education
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• v.21 no.2
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• pp.511-530
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• 2011

This study aims to find out science talented students' percentage of cognition about the views of nature of science and science inquiry which are essential for having a good understanding with science concepts. Each group of 40 science gifted students and 35 ordinary students was tested with a test of views of nature of science and science inquiry which consisted of 19 items with index of content validity 97% and reliability index 0.86, then its results being compared and analyzed. A group of science gifted students' percentage of cognition about the views of nature of science ranges from 20% to 97.5% -although it differs according to detailed views-showing its mean of 67% (50% in a group of ordinary students). Especially, the percentage of cognition about the sub view that there can be different opinions among scientists was high among woman science gifted students. A group of science gifted students' percentage of cognition about the views of science inquiry ranges from 27.5% to 77.5% -although it differs according to detailed views- showing 53% in their mean (41.8% in a group of ordinary students). Especially, the percentage of cognition about the sub view that scientists can have different research methods was high among woman science gifted students. The percentage of mistaken cognition by science gifted students about views of nature of science and about views of science inquiry was 33%, 47% respectively.