• Journal of Computing Science and Engineering
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• v.6 no.2
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• pp.79-88
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• 2012

Power continues to be a driving force in central processing units (CPU) design. Most of the advanced breakthroughs in power have been in a realm that is applicable to workstation CPUs. Advanced power management systems will manage temperature, dynamic voltage scaling and dynamic frequency scaling in a CPU. The use of power management systems for microcontrollers and embedded CPUs has been modest, and mostly focuses on very large scale integration (VLSI) level optimizations compared to system level optimizations. In this paper, a dynamic frequency controlling (DFC) technique is introduced, to lay the foundation of a system level power management system for commercial microcontrollers. The DFC technique allows a commercial microcontroller to have minor modifications on both the hardware and software side, to allow the clock frequency to change to save power; results in this study show a 10% savings. By adding an additional layer of software abstraction at the interrupt level, the microcontroller can operate without having knowledge of the current clock frequency, and this can be accomplished without having to use an embedded operating system.

• Korean Journal of Child Studies
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• v.36 no.1
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• pp.125-146
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• 2015

The "Child Care and Education Policy(CCEP)" is important because it is responsible for providing 'care and education service' to young children in their 'most sensitive period' of human development. In reality, however, children's rights can only be sanctioned by adults and their rights are recognized at the level of abstraction. This study analyzes the 'Child Edu-care Act(CEA)' first enacted in 1991 from the 'perspective of children's rights', especially in terms of the rights of infants and preschoolers. In order to assess the CEA's "children's rights guarantee level", this study developed a number of standards based on the "UN Convention on the Rights of the Child(CRC)" and other documents. The results revealed that "children's rights guarantee level" was assessed against 4 categories ('Right to Survival and Development', 'Right to Welfare', 'Right to Education', and 'Right to Proper Care'), and the CEA(1991) was found to have a high guarantee level although it was enacted before Korea's ratification of the CRC. The results of this study can serve as a useful reference point for detailing children's rights and suggesting regulation standards for the CCEP.

• The Journal of Engineering Geology
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• v.30 no.2
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• pp.119-129
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• 2020

Sand dam is a successful water harvesting method in mountainous areas with ephemeral rivers. The success is dependent on several factors including material type, hydrogeology, slope, riverbed thickness, groundwater recharge, and streamflow. In this study, the effect of a sand dam on the groundwater level in the Chuncheon area, South Korea was assessed using the MODFLOW model. Using the model, multiple scenarios were tested to understand the groundwater head before and after the construction of the sand dam. The effect of groundwater abstraction before and after sand dam construction and the sand material type were also assessed. The results show, the groundwater level increases substantially after the application of a sand dam. The comparison of model outputs, simulated groundwater head before and after sand dam application with and without pumping well, shows a clear difference in the head. The material type has also an effect on the groundwater head. As the conductivity of the material increases, the head showed a significant rise.

• Journal of The Korean Association of Information Education
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• v.23 no.3
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• pp.207-217
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• 2019

In order to improve computational thinking, elementary schools have been using 'Scratch' to provide basic programming education. However, the study on evaluation of computational thinking is at an early stage. Therefore, this study evaluated the conceptual level of computational thinking using the scratch code analyzing. For this, Dr. Scratch was used to analyze 179 scratch projects. The results showed that the conceptual level of computational thinking of most elementary students was at the developing level, and that it varied according to gender and production style, showed the lowest level of logic and abstraction, and improved computational thinking during programming. This study is meaningful in that it provides implications for the improvement of teaching methods and self-directed evaluation in learning.

• Journal of Educational Research in Mathematics
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• v.8 no.1
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• pp.199-216
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• 1998

One of the main features of the 7th revised national curriculum is the implementation of a 'Differentiated Curriculum'. Differentiated Curriculum is often interpreted as meaning the same as 'tracking' or 'ability grouping' in western countries. In the 7th revised curriculum, mathematics is organized and implemented by 'Level-Based Differentiated Curriculum'. To develop mathematics textbooks and teaching-and-learning materials for Differentiated Curriculum, the ideas of 'Enriched and Supplemental Differentiated Curriculum'need to be applied, that is, to provide advanced contents for fast learners, and plain contents for slow learners. Level Based Differentiated Curriculum could be implemented by ability grouping either between classes or within classes. According to these two exemplary models, the implementation models for supplemental course and enriched course are determined. The contents for supplemental course are comprised of minimal essential elements selected from the standard course at a decreased level of complexity and abstraction. The contents of enriched courses are focused on various applications of mathematical knowledge in the real world. Special remedy course will be offered to extremely underachieved students, The principles of developing teaching-and-learning material for special remedy course were obtained from the histo-genetic principle, progressive mathematizing principle, and constructivism.

• The KIPS Transactions:PartD
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• v.14D no.7
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• pp.753-762
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• 2007

Traceability has been held as an important factor in testing activities as well as model driven development. Vertical traceability affords us opportunities to improve manageability from models and test cases to code in testing and debugging phase. Traceability also makes overcome to difficulties of going up-and-down abstraction level to find out error spot of faults discovered by testing This paper represents a vertical test method which connects a system test level and an integration test level in a test stage by using UML. Experiment of how traceability works and how effective focus on error spots has been included using concrete examples of tracing from models to the code.

• Journal of Ocean Engineering and Technology
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• v.36 no.1
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• pp.41-49
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• 2022

With the advancement of intelligent vehicles and unmanned systems, there is a growing interest in underwater surveys using autonomous marine vehicles (AMVs). This study presents an automated planning strategy for a long-term survey mission using a fleet of AMVs consisting of autonomous surface vehicles and autonomous underwater vehicles. Due to the complex nature of the mission, the actions of the vehicle must be of high-level abstraction, which means that the actions indicate not only motion of the vehicle but also symbols and semantics, such as those corresponding to deploy, charge, and survey. For automated planning, the planning domain definition language (PDDL) was employed to construct a mission planner for realizing a powerful and flexible planning system. Despite being able to handle abstract actions, such high-level planners have difficulty in efficiently optimizing numerical objectives such as obtaining the shortest route given multiple destinations. To alleviate this issue, a widely known technique in operations research was additionally employed, which limited the solution space so that the high-level planner could devise efficient plans. For a comprehensive evaluation of the proposed method, various PDDL-based planners with different parameter settings were implemented, and their performances were compared through simulation. The simulation result shows that the proposed method outperformed the baseline solutions by yielding plans that completed the missions more quickly, thereby demonstrating the efficacy of the proposed methodology.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.10 s.352
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• pp.68-73
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• 2006

This, paper proposes a cosimulation methodology that results in an efficient SoC design as well as fast verification by integrating HDL, SystemC, and algorithm-level abstraction using the design tools Active-HDL and Matlab's Simulink. To demonstrate the proposed design methodology, we implemented the design technique on a serial connection multi-channel speaker system. We have demonstrated the proposed cosimulation method utilizing an ARM processor based SoC Master board with the AMBA bus interface and a Xilinx Vertex4 FPGA. The proposed method has the advantage of simultaneous simulation verification of both software and hardware parts in high levels of abstraction mixed with some performance critical parts in more concrete RTL codes. This allows relatively fast and easy design of a speaker connection system which typically requires significant amount of data processing for verification.

• The Korean Journal of Applied Statistics
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• v.29 no.6
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• pp.1077-1094
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• 2016

Apache Spark is a fast and general-purpose cluster computing package. It provides a new abstraction named resilient distributed dataset, which is capable of support for fault tolerance while keeping data in memory. This type of abstraction results in a significant speedup compared to legacy large-scale data framework, MapReduce. In particular, Spark framework is suitable for iterative machine learning applications such as logistic regression and K-means clustering, and interactive data querying. Spark also supports high level libraries for various applications such as machine learning, streaming data processing, database querying and graph data mining thanks to its versatility. In this work, we introduce the concept and programming model of Spark as well as show some implementations of simple statistical computing applications. We also review the machine learning package MLlib, and the R language interface SparkR.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.1
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• pp.82-95
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• 2007

The paper focuses on how to classify as well as to define the Architecture Patterns which are popularly used in the design of software architecture. In order to achieve this purpose, we propose not only the revised methodology for Pattern-Oriented Software Architecture Design, but also new method of classification and definition for the Architecture Patterns. Especially, because the patterns are so diverse depending on the level of abstraction and types of applications, it was considered to have some different views of classification of the patterns in order to support convenient access to classified and stored patterns. The abstraction of the pattern is another important result of the research, which is devised for concrete expression of the patterns and for presentation of the interrelation among group of the patterns. The research also includes the extension of the quality model popularly adopted in the software domain, which enables the description of the patterns with the well defined quality attributes in terms of software architecture's point of view.