• Management Science and Financial Engineering
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• 제18권2호
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• pp.23-27
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• 2012

The problem of jointly determining a robust optimal bundle of price and order quantity for a retailer in a single-retailer, single supplier, single-product supply chain is considered. Demand is modeled as a decreasing power function of product price, and unit purchasing cost is modeled as a decreasing power function of order quantity and demand. Parameters defining the two power functions are uncertain but their possible values are characterized by ellipsoids. We extend a previous study in two ways; the purchasing cost function is generalized to take into account the economies of scale realized by higher product demand in addition to larger order quantity, and an exact transformation into an equivalent convex optimization program is developed instead of a geometric programming approximation scheme proposed in the previous study.

• Child Studies in Asia-Pacific Contexts
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• 제2권1호
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• pp.1-10
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• 2012

The present study, based on Tiffany Field's model of violence and intimacy as well as other previous research, examines the relationship between parents' physical affection and their child's aggressive behavior. One hundred seventy-five mothers and 124 fathers of Japanese preschoolers answered a questionnaire that included a parental physical affection scale developed for this study. Children's aggressive behaviors were rated by their teachers on the hostile-aggressive subscale of the Preschool Behavior Questionnaire. Consistent with Field's model and previous studies, the results of logistic regression analyses indicated that children who received more physical affection from mothers or fathers during daily parenting were less likely to be aggressive at preschool. When the mother's and the father's physical affection scores were simultaneously entered in the equation, only the father's score was significant. Implications and limitations of the research are discussed.

• East Asian mathematical journal
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• 제28권4호
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• pp.363-381
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• 2012

The purpose of this study to analyze correlation for the tendency of mathematics anxiety, traits according to the factors of mathematics anxiety and mathematics attitude depending on the teacher variable through a survey of mathematics anxiety and attitude toward mathematics on teaching mathematics of elementary school teachers. To solve the questions above, sampled 250 elementary school teachers in Daegu province. As a result of the study, mathematics anxiety on teaching is not actually formed a lot. However, the more training experience with mathematics, previous academic career, education career were, the lower mathematics anxiety was. The results showed that mathematics anxiety is affected by previous academic career, training experience with mathematics in particular. In addition, we found that mathematics anxiety is affected by mathematics anxiety in their school, recognition of the ability to explain mathematics contents and attitudes toward mathematics.

• International Journal of Fluid Machinery and Systems
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• 제4권1호
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• pp.114-132
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• 2011

We have proposed a new approach based on energy gradient concept for the study of flow instability and turbulent transition in parallel flows in our previous works. It was shown that the disturbance amplitude required for turbulent transition is inversely proportional to Re, which is in agreement with the experiments for imposed transverse disturbance. In present study, the energy gradient theory is extended to the generalized curved flows which have much application in turbomachinery and other fluid delivery devices. Within the frame of the new theory, basic theorems for flow instability in general cases are provided in details. Examples of applications of the theory are given from our previous studies which show comparison of the theory with available experimental data. It is shown that excellent agreement has been achieved for several configurations. Finally, various prediction methods for turbulent transition are reviewed and commented.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.69-70
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• 2018

With increased interest in the Fourth Industrial Revolution, there is also a growing interest in the innovation of college education. In this regard, this study aims to develop a learning model for building construction to nurture architectural engineers needed in the era of the Fourth Industrial Revolution. To this end, it analyzed the previous studies on the recent innovations in engineering education. Among the educational innovation methods presented in the previous research, a new learning model was derived by using the most suitable method for the building construction eduction. The derived learning model is a building construction learning model applying team-based learning and flipped learning. The learning model proposed in this study was developed as a learning method to nurture engineers needed in the future. Therefore, it is expected that this model can be utilized in the eduction of architectural engineering at universities in Korea.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1957-1962
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• 2004

The objective of this study is to perform the numerical investigation of flow characteristics in static mixers. Simulations are carried out for mixers consisting of up to six Kenics and PPM elements placed end-to-end at an angle of $90^{\circ}$and for a range of Reynolds number($1{\leq}Re{\leq}100$). The pressure drop across a six-element Kenics mixer is computed and compared with the previous experimental correlations. The results are in good agreement with the previous correlations. The simulated flow field of Kenics mixer is extremely complex and contains regions of transverse flow that is dominated by the interaction of vortices produced by the mixer elements.

• ETRI Journal
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• 제33권2호
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• pp.291-294
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• 2011

This letter proposes an open-ended waveguide antenna with a single split-ring resonator. In contrast to the waveguide antennas incorporating multiple rings reported in a previous study, which exhibited narrow bandwidth, the proposed antenna uses only one ring to achieve broader bandwidth while keeping the aperture small. A single ring has a relatively low quality factor compared to multiple rings. The simulated and measured fractional bandwidth was 4.13% and 4.03%, respectively, which is much broader than the fractional bandwidth of about 1% demonstrated in a previous study. This simple technique can be used in many applications that require small apertures including near-field probes and array elements.

• 대한안전경영과학회지
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• 제9권4호
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• pp.29-38
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• 2007

We adapted association rules of data mining in order to investigate the relation among the factors of musculoskeletal disorders and proposed the method of preventing the musculoskeletal disorders associated with multiple logistic regression in previous study. This multiple logistic regression was difficult to establish the method of preventing musculoskeletal disorders in case factors can't be managed by worker himself, i.e., age, gender, marital status. In order to solve this problem, we devised association rules of factors of musculoskeletal disorders and proposed the interactive method of preventing the musculoskeletal disorders, by applying association rules with the result of multiple logistic regression in previous study. The result of correlation analysis showed that prevention method of one part also prevents musculoskeletal disorders of other parts of body.

• Journal of Information Technology Applications and Management
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• 제12권2호
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• pp.63-77
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• 2005

With the progress of IT, the strategic use of information systems (IS) has been applied to the inter-organization business areas, that is called Inter-organization Systems (IOS). Previous IT diffusion researches or IT adoption researches have been focused to newly emerged IT but confined into individual organization. However, IOS such as internet relates with between organizations. In this sense, this research has analysed the IT diffusion factors affected by IOS based on the previous studies of IT adoption. This study employed a research model using the factors of adopting IOS in organization, and conducted an empirical research with questionaries with top domestic 80 firms. And the finding is that the factors of the CIO support, business partners and an industry community have significance but other factors such as the size of firm, the degree of IS maturity, the degree of firm centrality, the complexity or suitability of IOS does not.

• 전기학회논문지
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• 제58권9호
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• pp.1689-1694
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• 2009

In a previous paper, the characteristics of ECC (earth continuity conductor) have been analysed for reducing the level of induced sheath voltage considering the dimension and position of ECC, the spacing between ECC and three phase cables, and the use of two ECC conductors at the single point boned section of underground power cable system. From these results, the study conditions for optimal installation has been selected such as installation section, conductor size and etc. In this paper, 5 cases which are set by possible installation conditions are tested based on previous research results. Finally, the optimal installation method of ECC is selected on underground power cable systems.