• Journal of Educational Research in Mathematics
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• v.26 no.1
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• pp.47-62
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• 2016

Cultivating mathematical creativity is one of the aims in the recently revised mathematics curricular. However, there have been lack of researches on how to nurture mathematical creativity for ordinary students. Perspective of Realistic Mathematics Education(RME), which pursues education of creative person as the ultimate goal of mathematics education, could be useful for developing principles and methods for cultivating mathematical creativity. This study reanalyzes RME from the points of view in mathematical creativity education. Major findings are followed. First, students should have opportunities for mathematical creation through mathematization, while seeking and creating certainty. Second, it is vital to begin with realistic contexts to guarantee mathematical creation by students, in which students can imagine or think. Third, students can create mathematics in realistic contexts by modelling. Fourth, students create the meaning of 'model of(MO)', which models the given context, the meaning of 'model for(MF)', which models formal mathematics. Then, students create MOs and MFs that are equivalent to the intial MO and MF given by textbook or teacher. Flexibility, fluency, and novelty could be employed to evaluate the MOs and the MFs created by students. Fifth, cultivation of mathematical creativity can be supported from development of local instructional theories by thought experiment, its application, and reflection. In conclusion, to employ the education model of cultivating mathematical creativity by RME drawn in this study could be reasonable when design mathematics lessons as well as mathematics curriculum to include mathematical creativity as one of goals.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.1
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• pp.42-56
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• 2002

It is possible but not efficient to model and simulate asynchronous microprocessors with the existing HDLs(HARDware Description Languages) such as VHDL or Verilog. The reason it that the description becomes too complex. and also the simulation time becomes too long to explore the design space. Therefore it is necessary to establish a methodology and develop a tool for modeling the handshake protocol of asynchronous microprocessors very easily and simulating it very fast. Under this objective an efficient CAD(Computer Aided Design) tool SLEDS(System Level Event-Driven Simulator) was developed which can evaluate performance of a processor through modeling with a simple description an simulating with event driven engine in the system level. The ultimate goal in the tool SLEDS is to fin the optimal conditions for a system to produce high performance by balancing the delay of each module in the system. Besides SLEDS aims at verifying the design through comparing the expected results with the actual ones by performing the defined behavior.

• Journal of The Korean Association For Science Education
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• v.36 no.1
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• pp.15-28
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• 2016

The purpose of this study is to investigate the changes of students' modeling ability in terms of 'meta-modeling knowledge' and 'modeling practice' through co-construction of scientific model. Co-construction of scientific model instructions about astronomy were given to 41 middle-school students. The students were given a before and after instruction modeling ability tests. The results show that students' 'meta-modeling knowledge' has changed into a more scientifically advanced thinking about models and modeling after the instruction. Students were able to be aware that 'they could express their thoughts using models', 'many models could be used to explain a single phenomena' and 'scientific models may change' through co-construction modeling process. The change in the 'modeling practice' of the students was divided into four cases (the level improving, the level lowering, the high-level maintaining, the low-level maintaining) depending on the change of pre-posttest levels. The modeling practice level of most students has improved through the instruction. These changes were influenced by co-construction process that provides opportunities to compete and compare their models to other models. Meanwhile, the modeling practice level of few students has lowered or maintained low level. Science score of these students at school was relatively high and they thought that the goal of learning is to get a higher score in exams by finding the correct answer. This means that students who were kept well under traditional instruction may feel harder to adapt to co-construction of scientific model instruction, which focuses more on the process of constructing knowledge based on evidences.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2008.04a
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• pp.253-258
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• 2008

우리나라에서 원자력 시설의 안전 확보를 위한 현장 규제는 원전 부지내에 설치되어 운용되고 있는 주재관실과 방사능 재난 발생에 대응하기 위한 현장방사능방재지휘센터 등으로 분산되어 있다. 원유 고유가, 에너지 안보, 및 기후 변화 협약 등에 대한 대응책으로, 신규 원자력 시설의 건설이 진행 중에 있으며, 이에 따라 원자력 규제 대상이 증가하고 있다. 지역주민이 신뢰하는 원자력 시설의 안전 규제의 필요성에 따라 현장 규제의 업무량도 증가하고 현장 규제 요건도 강화되고 있는 추세이다. 분산되어 있는 원자력 안전규제 시스템을 통합적인 체계로 전환하기 위한 방안들 가운데, 이 연구에서는 규제의 효율성/효과성을 향상시키기 위해 원자력 안전 지역사무소의 설치가 고려되었다. 이 연구의 주요 목적은 시스템 다이내믹스 기법을 활용한 지역사무소 설치의 타당성 모델을 제시하는 것이다. 이 SD 모델을 통해 지역사무소 설치가 규제 효과성을 포함한 다른 변수들에 미치는 영향을 전체론적 (holistic) 관점에서 평가할 수 있다. 이 SD 모델에서 이해관계자 (예: 중앙행정기관, 규제기관, 지방자지단체, NGO, 국민 등) 각각의 우선적인 목표는 갈등적 다중목표가 된다. 이러한 다중목표는 원자력 안전 규제의 의사결정 단계에서 거버넌스(governance) 체제 (예: 규제 기관, 사업자, 지역주민 등이 참여하는 체제)의 구축, 원자력 관련 민원 해결을 통해 성취될 수 있다. 시스템 다이내믹스 접근법의 주요 변수 정의 단계에서는 다양한 관점의 상호영향을 고려하면서 지역사무소 설치에 필요한 기본 개념이 도출되었다. 시스템 다이내믹스 접근법의 모델링 단계에서는 이들 기본 개념에서부터 지역사무소 설치 타당성 정책의 인과 지도(causal map)가 작성되었다. 이러한 인과 지도들로부터 지역사무소의 설치 타당성으로 이끄는 다양한 자기-강화 (self-reinforcing) 루프들이 발견되었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2441-2451
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• 2012

This paper presents the design of a control system for improving performance of a washer fluid heating system (WFHS) which is capable of removing frost, ice, snow and/or other debris from windshield. First, for the WFHS, a modeling process is described, and the extraction of characteristic parameters of the model are made by experimental studies. Design variables that affect on performance of the WFHS are also presented. Secondly, a control system is proposed for improving heating performance of the WFHS, and its performance is verified through experiments. The key feature of the proposed control system is to regulate the current of a booster converter input to the WFHS up to the target value that is set to guarantee heating performance. Target current is calculated by using initial temperature value and employing the mathematical model derived in the paper. Computer simulation and experimental results show that the proposed control system can perform heating operations in a way to satisfy per-determined target performance of the WFHS.

• Journal of KIISE:Software and Applications
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• v.35 no.7
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• pp.424-430
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• 2008

Identifying crosscutting concerns during requirements engineering phase is one of the most essential parts in Aspect-Oriented Software Development. Considering crosscutting concerns in the earlier phase of the development improves consistency among requirements so that it can help maintain software systems efficiently and effectively. It also provides a systematic way to manage requirements changes by supporting traceability throughout the software lifecycle. Thus, identifying tangled and scattered concerns, and encapsulating them into separate entities must be addressed from the early phase of the development. To do so, first, functional and non-functional concerns must be clearly separated. Second, a pointcut where a main concern meets crosscutting concerns should be defined and specified precisely. Third, it is required to detect conflicts being occurred during composition of crosscutting concerns from the earlier phase. Therefore, this paper proposes a systematic approach to identifying and specifying crosscutting concerns using goal-scenario based requirements analysis. And we demonstrate the applicability of the approach by applying it into the intelligent service robot system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8B
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• pp.1424-1435
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• 2000

A bit-rate controller that can achieve a constant bit rate when coding object-based video sequences is an important part to achieve an adaptation to bit-rate constraints, desired video quality, distribution of bits among objects, relationship between texture and shape coding, and determination of frame skip or not. Therefore we design content-based bit rate controller which will be used for relevant bit-rate control. The implementation is an extension of MPEG-4 rate control algorithm which employs a quadratic rate-quantizer model. The importance of different objects in a video is analyzed and segmented into a number of VOPs which are adaptively bit-allocated using the object-based modelling. Some test sequences are observed by a number of non-experts and interests in each object are analysed. The initial total target bit-rate for all objects is obtained by using the proposed technique. Then the total target bits are jointly analyzed for preventing from overflow or underflow of the buffer fullness. The target bits are distributed to each object in view of its importance, not only of statistical analysis such as motion vector magnitude, size of object shape, and coding distortion of previous frame. The scheme is compared with the rate controller adopted by the MPEG-4 VM8 video coder by representing their statistics and performance.

• Journal of Digital Convergence
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• v.11 no.10
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• pp.47-57
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• 2013

Big data analysis needs a new tool for decision making in view of data volume, speed, and variety. Many global IT enterprises are announcing a variety of Big data products with easy to use, best functionality, and modeling capability. Big data packages are defined as a solution represented by analytic tools, infrastructures, platforms including hardware and software. They can acquire, store, analyze, and visualize Big data. There are many types of products with various and complex functionalities. Because of inherent characteristics of Big data, selecting a best Big data package requires expertise and an appropriate decision making method, comparing the selection problem of other software packages. The objective of this paper is to suggest a decision making method for selecting a Big data package. We compare their characteristics and functionalities through literature reviews and suggest selection criteria. In order to evaluate the feasibility of adopting packages, we develop two Analytic Hierarchy Process(AHP) models where the goal node of a model consists of costs and benefits and the other consists of selection criteria. We show a numerical example how the best package is evaluated by combining the two models.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.61-68
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• 2015

Noise reduction is necessary to compensate for the degradation of recognition performance by various types of noises. Among many noise reduction techniques using microphone array, generalized sidelobe canceller (GSC) has been widely applied to reduce nonstationary noises. The performance of GSC is directly affected by its adaptation mode controller (AMC). That is, accurate target speech detection is essential to guarantee the sufficient noise reduction in pure noise intervals and the less distortion in target speech intervals. Thus, this paper proposes an improved AMC design technique in which the power ratio of the output of fixed beamforming to that of blocking matrix is calculated frequency bandwise and probabilistically modeled by mixture Gaussians for each class. Experimental results show that the proposed algorithm outperforms conventional AMCs in receiver operating curves (ROC) and output SNRs.

• Journal of Digital Convergence
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• v.18 no.12
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• pp.217-229
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• 2020

Globally, information protection of organization has become an essential management factor, and organizations continue to invest high-level resources for information security. Security threats from insiders are not decreasing. The purpose of this study is to present the antecedence factors to mitigate the role conflict that is the cause of the security avoid behavior. For the study, a survey was conducted for employees of organizations with information security policies, and structural equation modeling was conducted using a total of 383 samples for hypothesis verification. As a result of the analysis, role conflict increased avoid behavior, and goal difficulty, goal specificity, justice, and trust mitigated role conflict. In particular, justice influenced the reduction of role conflict and avoid behavior through trust. The implications were to present the causes and mitigation factors for avoid behavior of employee, and it is judged that it will help the organization to establish a security strategy.