• School Mathematics
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• v.11 no.4
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• pp.583-605
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• 2009

This research aims to examine the characteristics and main subjects of the mathematics class-criticism by elementary' teachers. In this aim, we analyzed the mathematics class-criticism by the 11 elementary teachers. As the results of this research, the elementary teachers criticized the mathematics class while understanding and describing the class as it is. And mathematics class-criticism by elementary teachers showed contextual and situational characteristics. Furthermore, the main subjects of mathematics class-criticism by elementary teachers were identified as mathematical communication, teacher's question to foster the students' mathematical thinking, appropriateness of task, motivation for students, concrete operational activity, appropriateness on teacher's mathematical behavior and teacher's use of mathematical term, experience of inductive reasoning. While, we identified the significance of mathematics class-criticism for elementary teachers. The elementary teachers pointed out the necessity and importance of the mathematics class-criticism on the mathematics class in usual context.

• Journal for History of Mathematics
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• v.21 no.4
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• pp.169-182
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• 2008

This study has been searching for reasoning process solving the problem effectively in activities related to meaningful classification of pieces and geometric properties with tangram. In activities using some pieces of tangram, we systematically came up with every solution in classifying properties of pieces and combining selected pieces. It is very difficult for regular students to do this tangram. In order to solve this problem effectively, we need to show that there are activities using the idea acquired in reasoning process. Through this process, we do not simply use tangram to understand he concept and play for interest but to use it more meaningfully. And the best solution an not be found by a process of trial and error but must be given by experience to look or it systematically and methods to reason it logically.

• Journal of Educational Research in Mathematics
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• v.27 no.2
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• pp.227-247
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• 2017

The purpose of this study is to investigate the differences in the meanings of two $7^{th}$ grade students over 'a' in expressing and interpreting a function of the form of 'y=ax+b(a, b is a constant, $a{\neq}0$)', and to identify causes of the differences. We collected data from a teaching experiment with four $7^{th}$ grade students who participated in 23 teaching episodes. Analysis of the collected data revealed marked differences between student A and student B in expressing and interpreting given situations with linear functions. The differences between the two students and the causes of differences were also analyzed. The results show that the students expressed and interpreted 'a' in the linear function 'y=ax+b', on the basis of their construction of quantities and their quantitative relationships in a given situation involving a constant rate of change.

• The Journal of the Korea Contents Association
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• v.15 no.11
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• pp.215-226
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• 2015

As violent video game is used based on active interaction and involvement of users, it is widely thought that it may have more effect on individual violence and aggressive action than existing violent videos. This study aimed to examine the effect of user experiences in the violent video game such as hostility, anger, arousal, enjoyment and identification on users' aggressive action. For this purpose, the first person FPS shooting game that consists of violent contents was employed to carry out playtest for 80 subjects with 40 male and 40 female university students. As a result, it was found that the user's arousal level, state anger, enjoyment and identification experience by the use of violent video game had an effect on aggressive action. Among factors that have aggressive action in the used of violent video game, besides emotion and arousal, the level of identification with a game character was found to be important effect factor. Hostility factor that was assumed to have effect on aggressive action was not significant, but enjoyment of game was proved to have effect on aggressive action of users.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12B
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• pp.1758-1765
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• 2010

This paper proposes an architecture exploration methodology for the design of embedded cores exploiting design hierarchy. The proposed method performs systematic architecture exploration by taking different approaches for verifying designs and estimating performances depending on the hierarchy level in design process. Performance estimation tools generate profile having performance data related with design modules of an embedded core. Profile analyzer performs data-mining to acquire association rules between the design modules and performance parameters. Inference engine in the profile analyzer updates the association rules which will be used to improve the design performance at next exploration steps. To show the efficiency of the proposed architecture explorations methodology, experiments had been performed for JPEG encoder, Chen-DCT, and FFT application functions. The embedded cores designed by taking the proposed method show performance improvement by 60.8% in terms of clock cycles on the average when compared with the initial embedded core in MIPS R3000.

• The Journal of Society for e-Business Studies
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• v.17 no.2
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• pp.63-72
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• 2012

The Korean telecommunications market has been expanding swiftly, these days, to be saturated. In this environment, the upcoming mobile telecommunication market, where 4G service was introduced this year, is becoming more substitutive and competitive. Thus, the demand forecasting of 4G service is very difficult, while it is critical to market success. This paper adopts a multi-generation diffusion model to capture the diffusion and substitution patterns for two successive generation of technological services, i.e., 3G and 4G mobile telecommunications services. The three parameters, i.e., the coefficient of innovation, the coefficient of imitation, and the coefficient of market potential, used in the multi-generation diffusion model based on Norton and Bass[11] are obtained by inference from similar substitutive relations between older and newer telecommunication services to 3G and 4G services. The simulation results show that the Bass type multi-generation model can be successfully applied to the demand forecasting of newly introduced 4G mobile telecommunication service.

• Korean Journal of Weed Science
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• v.11 no.2
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• pp.122-127
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• 1991

The allelopathic effects of rice and barley straws on lettuce germination and weed growth were investigated. The grinded straw of rice significantly inhibited lettuce germination. Both rice and barley straws decreased weed growth when they were used as a mulch in the field. Rice straw mulch applied with 500g/$m^2$ and 700g/$m^2$ decreased dry weight of Alopecurus aequalis more than 35%. Barley straw mulch applied with 200 g/$m^2$ inhibited dry weight of Echinochloa curs-galli and Digitaris sanguinalis, while the straw applied with 300 g/$m^2$ decreased those by 97%.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.475-480
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• 2008

In BTL project, the operation cost covering upcoming 20 years is usually alloted more than construction cost although its plan is made in short time. Therefore, it is a key issue to forecast and to analyze operation risks in the process of making contract in order to successfully finish the BTL project and to ensure the profitability of business. However, only a few domestic professional management companies are capable to carry out funding and facility management. To manage the potential risks efficiently in BLT project, it's essential to prioritize the risk factors by means of considering economical risk level, non-economical risk level and occurrence frequency. Thus, this study suggests risk analysis model for improving efficiency of BTL project from operation company's perspective by means of survey. The suggested risk analysis model is expected to establish a risk management strategy which can improve the efficiency of management affairs in BTL project.

• The Journal of Bigdata
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• v.1 no.1
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• pp.61-66
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• 2016

With big data analysis, companies use the customized marketing strategy based on customer's information. However, because of the concerns about privacy issue and identity theft, people start erasing their personal information or changing the privacy settings on social network site. Facebook, the most used social networking site, has the feature called 'Likes' which can be used as a tool to predict user's demographic profiles, such as sex and age range. To make accurate analysis model for the study, 'Likes' data has been processed by using Gaussian RBF and nFactors for dimensionality reduction. With random Forest and 5-fold cross-validation, the result shows that sex has 75% and age has 97.85% accuracy rate. From this study, we expect to provide an useful guideline for companies and marketers who are suffering to collect customers' data.

• Information and Communications Magazine
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• v.31 no.12
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• pp.17-24
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• 2014

빅데이터, IoT, 클라우드 인프라 등 기술의 발달에 따라 일상생활 중에서도 개인과 환경의 변화에 대해 실시간 데이터 수집이 용이하게 되었다. 이를 활용하여 개인의 다양한 특성과 상황을 인지하고 다면적으로 의미를 분석할 수 있는 개인의 라이프스타일(lifestyle, 생활습관) 분석 기술이 중요하게 부각되고 있다. 이 라이프스타일 데이터는 개인의 질병이나 사회 심리적 문제의 원인 분석과 미래 트렌드의 변화예측을 할 수 있는 중요한 근거로 활용된다. 최근 이를 위한 연구로서 활동량, 스트레스, 위치, 수면 등의 라이프스타일 패턴을 추출하여 체계적인 프로세스로 삶의 질을 향상시키는 웰니스 (Wellness) 예측케어 서비스 연구와 서비스들이 활발히 진행되고 있다. 하지만 이러한 서비스를 제공하기에 앞서 개인의 복잡한 라이프스타일 패턴의 추출이 단편적으로만 이뤄지고 있어서, 패턴들 사이의 복잡한 관계를 분석하거나 연계 서비스로의 확장 및 라이프스타일 패턴의 재사용적인 측면에서의 문제가 어려운 이슈가 되고 있다. 이 때문에 웰니스 서비스의 신뢰도가 낮아 사용자가 단순히 재미로 느끼는 수준이거나 일회성에 그치는 모바일 어플리케이션 서비스를 제공받는 경우가 다반사이다. 본 논문에서는 IoT환경에서 다양한 스마트 디바이스에 의해 수집되는 라이프로그로 부터 라이프스타일 패턴 추출 및 모델링, 라이프스타일 패턴 분석으로부터 개인의 행동 추론 및 예측, 원인파악과 관련 지표를 정량적으로 설계하는 분석 엔진 개발 방안, 서비스 디자인을 통하여 실효적인 생활개선의 변화를 유도하는 기술, 개인의 심리적 특성까지 고려한 신뢰성 높은 케어 서비스 제공까지의 전반적인 웰니스 예측케어 서비스시스템 프로세스 및 플랫폼 설계 방안을 제시한다.