• Communications of Mathematical Education
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• v.27 no.3
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• pp.221-248
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• 2013

Among five types of the model textbook based on storytelling, the type of 'Inquiry into history of Mathematics' focuses on adapting the logic of mathematical discovery to the organization of mathematical contents. It enables students to recognize that mathematics has been developed by human needs and creativity while they are engaged in the story about knowledge formation. Moreover the textbook offers the context in which students are able to understand mathematical insights and logics hidden in the subject matter, so that they can reinvent and develop mathematical knowledge. In this study, we found the principles for development of the textbook based on storytelling for 'Inquiry into History of Mathematics' by analyzing the chapter about 'Complex number and Quadratic Equations' of the model textbook. The chapter was implemented in classroom environment and students' understanding of the subject matter and their perception on the textbook based on storytelling were surveyed before and after the implementation. The results showed the possibilities of adapting the textbook based on storytelling and we suggested some implications for further development.

• Information Systems Review
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• v.9 no.1
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• pp.311-341
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• 2007

This paper presents a case study on BSC(Balanced Scorecard) system development of Korea Post as a Korean public firm. BSC models of public or private sector are generally developed in different types due to their different strategic goals. Korea Post as a government firm has dual characteristics of BSC similar to both public and private sector. This firm has the organizational type of public firms, not private firms. To date many government subsidiary organizations have already introduced BSC or are trying to introduce BSC, but have difficulty in developing BSC successfully because of insufficient understanding of BSC. Based on a case study of Korea Post, this study analyzed key success and failure factors and suggested prospects on BSC system development of public firms.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.5
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• pp.487-494
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• 2011

The safety valve used in LNG/LNG-FPSO ships plays an important role in maintaining a fixed level of pressure by emitting LNG gas out of the pipes in the LNG piping system. The discharge coefficient is regarded as the most important factor in the valve performance. To satisfy the ship's classification, the discharge coefficient of the safety valve must usually be over 0.8. Despite the importance of understanding the flow phenomena inside the safety valve, the valve design is usually based on experience and experiments. We carried out a computational fluid dynamics (CFD) investigation using the ANSYS-CFX software. We observed the flow phenomena inside the valve and measured the discharge coefficients according to changes in the valve lift, which is the distance between the exit of the nozzle and the lower part of the disc plate. We verified our CFD results for the discharge coefficients using available experimental data.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.5
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• pp.423-430
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• 2014

Noise and vibration, which occur in a pipe, are usually caused by the interaction between the turbulent flow and nearby wall. Although it can be estimated by a simple case of expanded pipes having complex turbulent flow, the radiated noise is highly dependent upon the size, shape, and thickness of the given model. In addition, the radiated noise propagates and has serious interference and destabilization effects on the surrounding systems, which can lead to fatigue fracture and failure. This study took advantage of the variety of commercial programs, such as FLUENT (flow solver), NASTRAN (dynamic motion solver of complex structures) and VIRTUAL LAB (radiated noise solver) based on the boundary element method (BEM), to understand the underlying physics of flow noise. The expanded pipe has separation and a high pressure drop because of the abrupt change in the cross-section. Based on the radiated noise calculations, the noise level was reduced to around 20 dB in the range of 100-500 Hz.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.1
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• pp.9-17
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• 2013

A considerable deal of work has been carried out to get an insight into the gas-solid suspension flows and to specify the particle motion and its influence on the gas flow field. In this paper an attempt is made to develop an analytical model to study the effect of nozzle inlet/exit pressure ratio, particle/gas loading and the particle diameter effect on gas-solid suspension flow. The effect of the particle/gas loading on the mass flow, Mach number, thrust coefficient and static pressure variation through the nozzle is analyzed. The results obtained show that the presence of particles seems to reduce the strength of the shock wave. It is also found that smaller the particle diameter is, bigger will be the velocity as bigger particle will have larger slip velocity. The suspension flow of smaller diameter particles has almost same trend as that of single phase flow with ideal gas as working fluid. Depending on the ambient pressure, the thrust coefficient is found to be higher for larger particle/gas loading or back pressure ratio.

• 모자간호학회지
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• v.2 no.1
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• pp.34-44
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• 1992

지난 10년 동안 구미에서는 부모-아동 관계 영역에 혁신을 가져왔다. 특히 부모-아동 애착이론의 획기적인 변화로 가족 중심 출산 경험을 강조하고 있다. 과거에는 남편이 아내의 출산에 참여하던 것이 타부시되어 왔지만 애착의 개념이 대두되면서 남편도 출산에 함께 참여하도록 고려하여 임신에서부터 부부가 함께 이 과업을 완수하도록 모든 환경을 변화시키고 있다. 애착이론은 다양하여 정신분석이론, 학습이론, 인지발달이론과 동물 행동학적 측면에서 이해되고 있다. 다양한 이론적 배경과 개념들을 가지고 아버지-아동의 애착 및 유대관계에 대한 연구가 지난 10여년 이상 되어오고 있다. 가장 관심의 촛점이 되어 연구 되어온 것으로는 애착형성을 위해 중요하다고 하는 민감한 시기(Critical period)를 중심으로 애착의 특성인 시각, 청각, 촉각, 상호호혜적 관계, 긍정적 애정을 바탕으로 연구되어졌다. 이 연구는 부아 애착(Paternal Infant Attachment)의 연구를 연구방법, 측정도구 및 방법상문제와 변수들을 중심으로 재정리하여, 이 분야에 있어서 앞으로의 연구 방향을 살펴보았다. 17편의 연구들을 각각 년도, 표본수, 방법 및 측정, 결과 및 비고난을 비교 분석하여 도표를 작성하였다. 이론적 기틀과 문헌고찰에 근거하여 다음과 같은 적용과 제언을 한다. 1. 출산전 아버지의 특성에 대한 사정이 필요하다. 2. 연구자가 집단간 비교를 용이하게 하기 위해 연구전에 표본의 특성을 정확히 기술해야 한다. 3. 부모와 아버지의 과거력에 대한 상세한 정보수집이 강조되어야 한다. 4. 앞으로의 연구는 이론적 모델에 근거하여 이루어져, 대중교육 뿐 아니라 정책 결정에 기여해야 한다. 5. 연구결과 평가와 해석을 위해 정확한 이론적 근거가 필요로 된다. 6. 간호연구는 부적절한 부아 애착 형성에 있어서 아버지의 특성을 확인하고 부아유대와 애착 증진의 요소를 파악해야한다. 7. 부아 유대에 대한 위협요소 확인을 위한 도구개발과 그들에 대한 효과적인 간호전략이 필요 된다. 8. 가족에 있어서 모든 부모행위가 하나의 독립변수로서 연구되어야 하고 부아유대 증진에 관한 연구가 시도되어야겠다. 오늘날 부모들은 임신기간동안 많은 정보에 접하기를 원한다. 산전, 산후의 교육과 지식은 긍정적인 부아 관계를 증진시키고, 이것은 아동의 발달에 크게 기여할 수 있다. 긍정적으로 이러한 관계는 가족단위를 강하게 통합시키게 되므로 건강관리자(Health care workers)들은 애착에 대해 높은 관심을 갖어야 하겠다.

• Korean Journal of Childcare and Education
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• v.11 no.3
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• pp.85-102
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• 2015

The purpose of this study is to investigate the variables that affect the problem behavior of children and to examine the relationships between problem behavior of young children in relation to the child's characteristics(temperament and ego-resiliency), the mother's characteristics(parenting stress and personality characteristics), and the teacher's characteristics(teacher-child relationship and emotional expressiveness). The researcher surveyed 314 parents and 56 teachers of young children in the transitional period from 32 early childhood institutes in Daejeon. The summaries of the results of the study are as seen below. First, the child's gender and mother's education were statistically significant variables in explaining the variance in problem behavior of young children. More boys than girls showed more problem behaviors and children of mothers who graduated university showed less problem behavior. Second, teacher-child relationship was the most predictive variable in problem behavior of young children. Children who had good relationships with their teachers showed less problem behavior and children who had poor relationships with their teachers showed more problem behavior. The results of this study can provide basic data for consulting and developing program to prevent and treat the problem behavior of young children to consider the development of children.

• Journal of the Korea Society of Computer and Information
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• v.25 no.11
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• pp.41-50
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• 2020

Sentimental analysis begins with the search for words that determine the sentimentality inherent in data. Managers can understand market sentimentality by analyzing a number of relevant sentiment words which consumers usually tend to use. In this study, we propose exploring performance of feature selection methods embedded with Particle Swarm Optimization Multi Objectives Evolutionary Algorithms. The performance of the feature selection methods was benchmarked with machine learning classifiers such as Decision Tree, Naive Bayesian Network, Support Vector Machine, Random Forest, Bagging, Random Subspace, and Rotation Forest. Our empirical results of opinion mining revealed that the number of features was significantly reduced and the performance was not hurt. In specific, the Support Vector Machine showed the highest accuracy. Random subspace produced the best AUC results.

• Geophysics and Geophysical Exploration
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• v.19 no.1
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• pp.20-28
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• 2016

Recently many sinkholes have appeared in urban areas of Korea, threatening public safety. To predict the occurrence of sinkholes, it is necessary to investigate the existence of cavity under urban roads. Ground-penetrating radar (GPR) has been recognized as an effective means for detecting underground cavity in urban areas. In order to improve the understanding of the governing physical processes associated with GPR wave propagation, and interpret underground cavity effectively, a theoretical approach using numerical modeling is required. We have developed an algorithm employing a three-dimensional (3D) staggered-grid finite-difference time-domain (FDTD) method. This approach allows us to model the full electromagnetic wavefield associated with GPR surveys. We examined the GPR response for a simple cavity model, and the modeling results showed that our 3D FDTD modeling algorithm is useful to assess the underground cavity under urban roads.

• Journal of Convergence for Information Technology
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• v.7 no.3
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• pp.153-158
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• 2017

The certification for Smart Factory supoort successful management of organization while providing strategic plans to the issue of manufacturing process. In Korea, these standards are prepared as the national standards since 2015, and also, there are actions being taken to adpot the certification for Smart Factory. However, to adopt such certification, it is required that the certification operation system needs to be organized, as well as that the society in general should understand about Smart Factory. Accordingly, it is even more required an review on the adoption of the system. This study has the purpose in surveying a variety of atakeholders' perception for the adoption of Smart Factory certification given the circumstance that the cetitification is implemented through literature review and in-depth interviews. This study will be provide significant implication to build a successful plan for the adoption of Smart Factory certification by reviewing perception of professional and problem, strategy of this certification.