• Research in Mathematical Education
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• v.26 no.3
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• pp.147-166
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• 2023

Mathematics is a science of pattern. Mathematics is a subject of inquiring which aims at discovering the models hidden behind the world. Pattern is abstraction and generalization of the model. Mathematical pattern is a higher level of mathematical model. Mathematics patterns are often hidden in pattern similarity. Creation of mathematics lies largely in discovering the pattern similarity among the various components of mathematics. Inquiring is the core and soul of mathematics teaching. It is very important for students to study mathematics like mathematicians' exploring and discovering mathematics based on pattern similarity. The author describes an example about how to guide students to carry out mathematics inquiring based on pattern similarity in classroom.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.4
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• pp.143-150
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• 2013

The purpose of this study is to suggest the methodology to develop variable-scale network model, which is able to induce large-scale road network in detailed level corresponding to small-scale linear objects with various abstraction in higher level. For this purpose, the definition of terms, the benefits and the specific procedures related with a variable-scale model were examined. Second, representation level and the components of layer to design the variable-scale map were presented. In addition, rule-based data generating method and indexing structure for higher LoD were defined. Finally, the implementation and verification of the model were performed to road network in study area (Jeju -do) so that the proposed algorithm can be practical. That is, generated variable scale road network were saved and managed in spatial database (Oracle Spatial) and performance analysis were carried out for the effectiveness and feasibility of the model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.2
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• pp.154-173
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• 2010

Database outsourcing is unavoidable in the near future. In the scenario of data stream outsourcing, the data owner continuously publishes the latest data and associated authentication information through a service provider. Clients may register queries to the service provider and verify the result's correctness, utilizing the additional authentication information. Research on On-line Stream Analytics (OLSA) is motivated by extending the data cube technology for higher multi-level abstraction on the low-level-abstracted data streams. Existing work on OLSA fails to consider the issue of database outsourcing, while previous work on stream authentication does not support OLSA. To close this gap and solve the problem of OLSA query authentication while outsourcing data streams, we propose MDAHRB and MDAHB, two multi-dimensional authentication approaches. They are based on the general data model for OLSA, the stream cube. First, we improve the data structure of the H-tree, which is used to store the stream cube. Then, we design and implement two authentication schemes based on the improved H-trees, the HRB- and HB-trees, in accordance with the main stream query authentication framework for database outsourcing. Along with a cost models analysis, consistent with state-of-the-art cost metrics, an experimental evaluation is performed on a real data set. It exhibits that both MDAHRB and MDAHB are feasible for authenticating OLSA queries, while MDAHRB is more scalable.

• Journal of the Korean earth science society
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• v.39 no.4
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• pp.388-400
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• 2018

The purpose of this study was to explore the nine components of computational thinking (CT) practices and their operational definitions from the view of science education and to develop a CT practice framework that is going to be used as a planning and assessing tool for CT practice, as it is required for students to equip with in order to become creative problem solvers in $21^{st}$ century. We employed this framework into the earlier developed STEAM programs to see how it was valid and reliable. We first reviewed theoretical articles about CT from computer science and technology education field. We then proposed 9 components of CT as defined in technology education but modified operational definitions in each component from the perspective of science education. This preliminary CTPF (computational thinking practice framework) from the viewpoint of science education consisting of 9 components including data collection, data analysis, data representation, decomposing, abstraction, algorithm and procedures, automation, simulation, and parallelization. We discussed each component with operational definition to check if those components were useful in and applicable for science programs. We employed this CTPF into two different topics of STEAM programs to see if those components were observable with operational definitions. The profile of CT components within the selected STEAM programs for this study showed one sequential spectrum covering from data collection to simulation as the grade level went higher. The first three data related CT components were dominating at elementary level, all components of CT except parallelization were found at middle school level, and finally more frequencies in every component of CT except parallelization were also found at high school level than middle school level. On the basis of the result of CT usage in STEAM programs, we included 'generalization' in CTPF of science education instead of 'parallelization' which was not found. The implication about teacher education was made based on the CTPF in terms of science education.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.757-759
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• 2013

Until just a few years ago, digital circuit design techniques in register transfer level using Verilog or VHDL have been recognized as the up-to-date way compared with the traditional schematic design, and truly they have been used as the most popular skill for most chip designs. However, with the advent of era in which the complexity of semiconductor chip counts over billion transistors with advanced manufacturing technology, designing in register transfer level became too complex to meet the requirements of the needs, so the design paradigm has to change so that both design and synthesis can be done in higher level of abstraction. Bluespec SystemVerilog (BSV) is the only HDL which enables both circuit design and generating synthesizable code in the system level developed so far. In this contribution, I survey and analyze the features which supports the new paradigm in the BSV HDL, not very familiar to industry yet.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.3
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• pp.57-64
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• 2019

In this paper, an efficient prediction-based parallel simulation method using spatially partial simulation strategy is proposed for improving both the performance of the event-driven gate-level timing simulation and the debugging efficiency. The proposed method quickly generates the prediction data on-the-fly, but still accurately for the input values and output values of parallel event-driven local simulations by applying the strategy to the simulation at the higher abstraction level. For those six designs which had used for the performance evaluation of the proposed strategy, our method had shown about 3.7x improvement over the most general sequential event-driven gate-level timing simulation, 9.7x improvement over the commercial multi-core based parallel event-driven gate-level timing simulation, and 2.7x improvement over the best of previous prediction-based parallel simulation results, on average.

• Journal of KIISE:Software and Applications
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• v.26 no.10
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• pp.1178-1178
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• 1999

A spatial join has the property that its execution time exponentially increases in proportion to the number of spatial objects. Recently, there have been many attempts for improving the performance of the spatial join by using parallel processing schemes, In the case of executing parallel spatial join using the parallel machine with shared disk architecture, the disk bottleneck of parallel processing of spatial join worsens in comparison with sequential spatial join. This paper presents the algorithms of task creation and assignment to reduce the disk bottleneck caused by accessing the shared disk at the same time, and to minimize message passing between processors, This paper proposes object caching which is a higher level of abstraction than page caching, and uses it to do creation and assignment of tasks according to temporal and spatial localities for minimizing disk access time. The object caching shows the performance improvement of 50%. The task creation and assignment using localities gives the gain of 30% and 20%. Overall performance evaluation of the proposed algorithms shows 7.2 times speed up than those of sequential execution of spatial joins.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.5
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• pp.536-542
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• 2000

This paper proposes Visual Script Language which can direct a type of motion to 3D human model and create by dragging gesture like as we can express a certain meaning with hand gestures. Traditional motion control technique of articulated figures such as human needs a complex task that draws on highly developed human skills. So it will reduce the amount of motion specification to provide the motion control method that allow users to describe characters' motion at the higher level abstraction. Visual script is the visual gestures to direct various human motions, so users can express the spatial attributes of a motion such as the path of moving with high-level concepts if they use visual script. And we can show that it is possible to control the motion of human model directly and intuitively by development of 3D human motion control system based on visual script.

• Food Science and Preservation
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• v.10 no.3
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• pp.376-380
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• 2003

This aims is to estimate the consumers' preference on the brand rice using factor analysis, completed research on the consumption of brand rice revealed that the household supply in the Seoul area is increasing. An analysis whether housewives' preference in chosing the brand of rice was developed through the consumption experience and re-purchase intention investigation for the brand rice. Also the paper analyzed the consumers' preference using the logit and probit model. Number of respondents who participated in the study(95 ％) totaled 1000 and the sampling method utilized was the multistage stratification and assignment abstraction. Results showed that the preference of housewives' depends on age, education and level of income. Such that as age, education, income level increase so thus their preference for brand rices also increase. Also the re-purchasing of brand rice is high when housewives have a higher educational attainment and prefers to go to work. Conclusively, the long-term sale view for brand rice is closely related to the economic conditions of a household. Hence, with the economic growth, there is a possibility that consumption of brand rice would increase compared to the ordinary rice. We can propose the following political intent from analysis of these results. First, There is a need for continuous public information as reinforcement for brand rice. Second, Marketing operation reinforcement could also be done for customer class security etc.

• Journal of Science Education
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• v.39 no.3
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• pp.418-433
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• 2015

In this study, we investigated the cognitive characteristics of low science achieving middle school students in K-WISC-IV, and compared the results with high science achieving and achieving students. The results showed us that high science achieving students scored higher than counterparts in FSIQ. Low science achieving students scored lower than high science achieving and achieving students in VCI. Especially low science achieving students scored lower than two groups in subtest SI. The low level of abstraction in low science achieving students is due to the lack of scientific reasoning ability. Therefore subtest SI is considered as highly discriminating test for low science achieving group. Low levels in verbal comprehension, abstraction and reasoning ability are the major factors in poor school performance. High science achieving students scored more than achieving and low achieving students in WMI. Because the working memory is involved in scientific reasoning problem solving process, it is believed to play an important role in science achieved.