• Journal of Science Education
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• v.36 no.2
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• pp.341-353
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• 2012

The purpose of this study is to explore how science teachers' views about physics and biology are different. From a survey of 45 science teachers who majored in physics, this study found that their views about physics were closer to the experts' views than their views about biology. But it seemed that their views about neither physics nor biology were similar to the experts' views. Compared their views about physics with their views about biology in six dimensions, in four dimensions including structure dimension, methodology dimension, validity dimension, and reflective thinking dimension, the scores of the views about physics were higher, in learnability dimension, the scores of the views about biology were higher, and in personal relevance dimension, the scores of the two kinds of views were similar. Specially the their views about physics in learnability dimension were closer to novices'. In addition, science teachers majored in physics seemed to think that compared with biology, physics is coherent, systematic and reasoning, but it is not learnable.

• Journal of Korean Elementary Science Education
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• v.29 no.2
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• pp.195-206
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• 2010

The purposes of this study were to develop science education programs for changing students' science research ethical views, and to investigate the types and features of their views, and to examine their changes overtime. The subject of this study was one 6th grade class(41 students) at an elementary school located in Seoul. The scientific research ethical education programs developed in the study was applied through 8 lessons over 4 weeks. The results of this study show that 3 types of science research ethical views were appeared in elementary students participated in this study: 'human technology centered views', 'value ecology centered views' and the mixed views. The numbers of students, who changed their views from type I or type II to type III, were significantly increased. Students with type III appeared to actively involve in classroom activities aligned with science research ethical issues. The results imply that intended science ethical education program can affect students' ethical views on science. It is also important to aware that teacher's effective assistance and help contribute to students' meaningful changes on their traditional scientific ethical views. Educational implications on science education are discussed.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.1
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• pp.14-24
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• 2004

Views are essential in providing logical data independence for database systems. Object views in object-oriented/object-relational databases have requirements quite different from those of relational databases due to support for object-oriented concepts. Although many commercial object-oriented/object-relational database systems support object views, implementation techniques have not been discussed sufficiently in the literature. In this paper, we devise a technique for implementing views in object-oriented/object-relational databases and apply it to the ODYSSEUS object-relational database system. We first analyze the requirements of object views. Next, to implement object views, we extend the existing query modification algorithm that has been proposed for implementing views in relational databases. Next, we compare the features of the proposed object view with those of object views in commercial object-relational database systems. It is shown that the proposed object view supports all object-oriented concepts such as object identifiers, inheritance, methods, and composite objects, while existing object views support part of them. Last, we propose detailed techniques for implementing the extended query modification algorithm in the ODYSSEUS object-relational database system.

• Asia pacific journal of information systems
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• v.5 no.2
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• pp.131-142
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• 1995

In distributed database systems materialized views are useful to solve many problems caused by data replication. This paper deals with the problem of updating materialized views incluing join operations. We use a differential update which uses logs that record the change of base tables in certain periods. This method avoids locking of the base tables so that it makes the system more efficient. We update materialized views periodically to save the updating cost envolved. A screen test is applied to differential files to eliminate tuples that are irrelevant to any of the views being updated. Using these methods, a detailed procedure is addressed to refresh materialized views. Then we show that our update procedure performs better than a semijoin approach.

• IE interfaces
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• v.16 no.2
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• pp.229-239
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• 2003

The On-Line Analytical Processing (OLAP) tools access data from the data warehouse for complex data analysis, such as multidimensional data analysis, and decision support activities. Current research has lead to new developments in all aspects of data warehousing, however, there are still a number of problems that need to be solved for making data warehousing effective. View maintenance, one of them, is to maintain view in response to updates in source data. Keeping the view consistent with updates to the base relations, however, can be expensive, since it may involve querying external sources where the base relations reside. In order to reduce maintenance costs, it is possible to maintain the views using information that is strictly local to the data warehouse. This process is usually referred to as "self-maintenance of views". A number of algorithm have been proposed for self maintenance of views where they keep some additional information in data warehouse in the form of auxiliary views. But those algorithms did not consider a consistency of materialized views using view self-maintenance. The purpose of this paper is to research consistency problem when self-maintenance of views is implemented. The proposed "conveyor algorithm" will resolved a complete consistency of materialized view using self-maintenance with considering network delay. The rationale for conveyor algorithm and performance characteristics are described in detail.

• Journal of Korean Elementary Science Education
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• v.29 no.3
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• pp.243-251
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• 2010

The purpose of this study is to investigate the relationships between elementary school teachers' points of view about the organization of the science curriculum and their views on the nature of science (NOS). We surveyed 132 elementary school teachers' view points about these two kinds of views, analyzed the data by their variables, and compared the two viewpoints with their personal details. The elementary school teachers thought the science curriculum should be emphasized through the process more than contents. They thought the contents of the science curriculum should be integrated rather than separated. As teachers' career progressed, they focused on the contents more than the process. On the other hands, because elementary school teachers showed the NOS views as relativism, deductivism, decontextualism, content, and instrumentalism, when we plotted sub-viewpoints of NOS in process-content dimension, we thought it would be similar distributions with point of views on the organization of science curriculum. However, there was no meaningful relation. This showed that teachers' views on the organization of the curriculum and the NOS are totally different. These findings suggest further research is needed to find how factors influence elementary school teachers' views on the organization of the science curriculum and what inclinations can occur in science classes with their different views.

• Journal of The Korean Association For Science Education
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• v.24 no.6
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• pp.1158-1172
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• 2004

This study searched secondary school students' epistemological views and ontological views about nature and the root causes of such their views. The subjects were 156 secondary school students and data were gathered by the questionnaire developed based on preceding researches. As a result, many secondary school students had epistemological views of unknowable nature. There were various root causes of their epistemological views such as regularity and harmony of nature, predictable and circular natural phenomenon, causation, the relation between human and nature. On the other hand, a lot of secondary school students had ontological view of supernatural nature. Their religious beliefs were very powerful influence their supernatural ontological views. The nature is the object of science and the physical world. Because those views supply science educators basic backgrounds how leaners understand science class, secondary school students' epistemological views and ontological views are precious information. From now on, it is necessary to study relations between students' epistemological views and ontological views and their science class processes.

• Journal of The Korean Association For Science Education
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• v.15 no.1
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• pp.104-115
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• 1995

Teachers' conception about the nature of science is considered to be an important factor to improve the students' conceptions of that. It is assumed that teachers' conception of the nature of science may be influenced by their views of learning. The first purpose of this study was to investigate the exploratory relationships between teachers' conceptions about the nature of science and their views of learning. The second one was to compare the their conceptions and views of learning before and after science education lectures during 1 semester. We administered the questionnaires for the nature of science and for constructivist's learning, respectively, consisted of 5 dimensions (relativism-positivism; inductivism- deductivism; decontextualism-contextualism; content-process; instrumentalism-realism) and of 6 aspects (student; learning; instruction; teacher; curriculum; evaluations) were administered to 57 pre-service elementary teachers (female=44; male=13) before and after lectures. In pre-test it was revealed that respondents had not the consistent conceptions about the nature of science. The conception of relativism was more dominant than those of positivism, deductivism than inductivism, decontextualism than contextualism, process than content and instrumentalism than realism. They had more constructivist views in the respect of process of learning than in other respects, that is, students, instruction, teacher, curriculum and evaluation. But no significant correlations between the dimensions of the nature of science and the aspects of the views of learning suggest that constructivst views of learning was not deeply related with their conceptions of the nature of science. In post-test we had similar results with those of the pre-test, but the process-content dimensions of the nature of science was correlated with the constuctivist views of learning. Therefore we concluded that elementary pre-service teachers had the constructivist views of learning which was isolated with their conceptions of the nature of science although they had science educations course. We need to develop the course to make the conceptions of the nature of science relate view of learning.

• Journal of the Korean Society of Earth Science Education
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• v.12 no.3
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• pp.208-223
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• 2019

In this study, it was analyzed first the views of nature of elementary and middle school students using the analysis framework of the views of nature that reflects the results of the literature analysis on the traditional views of nature that Koreans traditionally have. Next, it was analyzed characteristics of the views of nature which elementary and secondary school teachers. Finally, it was discussed the implications of the results of analysis of students' and teachers' views on science education in elementary and secondary schools. For this purpose, the framework for analysis the views of nature was reconstructed by combining the characteristics of Korean's traditional views of nature (Lee & Son, 2017) with the framework developed by Cobern and his colleagues (Cobern, Gibson, & Underwood, 1995). And in order to analyze in depth how students and teachers perceive nature, each question was asked to write a reason why they thought about their responses. According to the study, students and teachers respected nature and viewed it as a living creature, and had the view that nature was cyclical and that humans and nature interacted with each other. And they also had a traditional Korean view of nature that they consider naturalness important and nature is beautiful. It can be said that this is different from the view of Western modern science which perceives the world as a material and see nature with the view of linear time. Therefore, Korea's traditional views of natures, which students and teachers have, can be a conflict with the view of modern science in science class. Therefore, the science teaching strategy for students and teachers with different natural views will require consideration of the individual's understanding of nature and lesson strategies related to it. And it is also necessary that science textbook and science class cultures need to actively interact with teachers and students, and between students to share and understand each other's view of nature, and create a science class culture that considers the values students have and views on nature.

• 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.