• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.148-155
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• 2006

Portable embedded systems which mainly handle multimedia applications involve the problem that frequent accesses to fetch data from memory make running time increased. To cope with the problem, embedded processors have adopted data prefetching schemes. From a power point of view, which is a main performance indicator of embedded systems, this paper analyzed to investigate how data prefetching schemes influence on system's performance. To solve the problem, we proposed a power-consumption analysis model of a memory system with data prefetching scheme and measured the power dissipated during running application programs. As a result data prefetching schemes have application program's running time reduced but have system's power increased. Also we proposed a performance analysis model considering execution time and power consumption for embedded system with data prefetching schemes.

• Interaction and multiscale mechanics
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• v.5 no.3
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• pp.211-228
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• 2012

This paper reports the development of a generalized inverse analysis formulation for the parameter estimation of four-parameter Burger model. The analysis is carried out by formulating the problem as a mathematical programming formulation in terms of identification of the design vector, the objective function and the design constraints. Thereafter, the formulated constrained nonlinear multivariable problem is solved with the aid of fmincon: an in-built constrained optimization solver module available in MatLab. In order to gain experience, a synthetic case-study is considered wherein key issues such as the determination and setting up of variable bounds, global optimality of the solution and minimum number of data-points required for prediction of parameters is addressed. The results reveal that the developed technique is quite efficient in predicting the model parameters. The best result is obtained when the design variables are subjected to a lower bound without any upper bound. Global optimality of the solution is achieved using the developed technique. A minimum of 4-5 randomly selected data-points are required to achieve the optimal solution. The above technique has also been adopted for real-time settlement of four oil refineries with encouraging results.

• Computers and Concrete
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• v.12 no.3
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• pp.261-283
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• 2013

This paper aims to contribute to the three-dimensional generalization of numerical prediction of crack propagation through the formulation of finite elements with embedded discontinuities. The analysis of crack propagation in two-dimensional problems yields lines of discontinuity that can be tracked in a relatively simple way through the sequential construction of straight line segments oriented according to the direction of failure within each finite element in the solid. In three-dimensional analysis, the construction of the discontinuity path is more complex because it requires the creation of plane surfaces within each element, which must be continuous between the elements. In the method proposed by Chaves (2003) the crack is determined by solving a problem analogous to the heat conduction problem, established from local failure orientations, based on the stress state of the mechanical problem. To minimize the computational effort, in this paper a new strategy is proposed whereby the analysis for tracking the discontinuity path is restricted to the domain formed by some elements near the crack surface that develops along the loading process. The proposed methodology is validated by performing three-dimensional analyses of basic problems of experimental fractures and comparing their results with those reported in the literature.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.4
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• pp.359-364
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• 2012

Real-Time Traversability should be analyzed from the equiped sensors' data in real time for autonomous outdoor navigation. However, it is difficult to find out such traversability that considers the terrain roughness and the vehicle dynamics especially in case of skid type vehicle. The traversability based on real time dynamic analysis was proposed to solve such problem but in navigation with strait driving path. To adapt the method into the navigation with curved driving path, a path following controller should be incorporated into the dynamic model even though it cause the real time problem. In this paper, a dynamic model is proposed to solve the real time problem in the traversability analysis based on real time dynamic simualtion. The dynamic model contains the control dummy which is connected to the vehicle body with a universal joint to follow the curved path without controller. Simulation and experimental results on $6{\times}6$ articulated unmanned ground vehicle demonstrate the method's effectiveness and applicability into the traversability analysis on terrain with bumps.

• Journal of the Korea Safety Management & Science
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• v.16 no.4
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• pp.159-165
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• 2014

For the hydrogen economy system being tried starting with the 21st century, the fields that was not dealt with so far, such as the safety measure for large leakage accidents, the safety problem at infrastructures like a hydrogen station, the safety problem in terms of automobiles depending on introduction of hydrogen cars, the safety problem in a supply for homes like fuel cells, etc., are being deeply reviewed. In order to establish a safety control system, an essential prerequisite in using and commercializing hydrogen gas as an efficient energy source, it is necessary to conduct an analysis, such as analysis of hydrogen accident examples, clarification of physical mechanisms, qualitative and quantitative evaluation of safety, development of accident interception technologies, etc. This study prepared scenarios of hydrogen gas leakage that can happen at hydrogen stations, and predicted damage when hydrogen leaks by using PHAST for this.

• Journal of the Korean Home Economics Association
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• v.34 no.5
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• pp.183-196
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• 1996

The purposes of this study were to review the effects of textiles production on the environment, and to investigate the environmental consciousness and environmental preservation behavior of textile producers. This study was conducted by reference analysis and empirical research. To develope theoretical framework of dimensions of environmental behavior, references concerned were analyzed. And for empirical study, researcher developed a questionnaire based on the free writing by producers and references. The questionnaire included problems about environmental consciousness, environmental behavior, demographic variables, and environmental variables. 135 questionnaires were used for final data analysis. ANOVA and factor analysis were used. The results were as follows: First, the level of global environmental problem consciousness was relatively high. The conscious level of water pollution caused by the waste water from textile mills was the highest, and that of desertation of mountain caused by timber cutting was the lowest. The effects of textile dyers and finishers on the environment were the highest, and that of designers were the lowest. Second, the results of reference analysis showed that the dimensions of textile producers environmental behavior were resource and energy saving, solid waste reduction, and green product production. And the results of empirical study were resource and energy saving, resource reuse or recycling, solid waste reduction, and green product production, and total variances was 62.3%. The practice was the lowest. Third, global environment problem consciousness, environment problem consciousness caused by the textile life-cycle concerned, and clothing seperate-collection or not at residing place were effective on environmental behavior, and 52.45% of environmental behavior was explained with above variables.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.976-983
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• 1988

An efficient unbalance response analysis method for rotor-bearing systems with spin speed dependent parameters is developed by utilizing a generalized modal analysis scheme. The spin speed dependent eigenvalue problem of the original system is transformed into the spin speed independent eigenvalue problem by introducing a lambda matrix, assuming the bearing dynamic coefficients are well approximated by polynomial functions of spin speed. This method features that it requires far less computational effort in unbalance response calculations and that the influence coefficients are readily available. In addition, the critical speeds and the corresponding logarithmic decrements can be readily identified from the resulting eigenvalues.

• Human Ecology Research
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• v.59 no.4
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• pp.433-448
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• 2021

The purpose of this study was to analyze two subject competencies (practical problem-solving capability and independent life capability) reflected in the activity tasks included in the 'home life and safety' area of 12 middle school technology-home economics textbooks in accordance with the 2015 revised curriculum. The analysis criteria were sub-elements of two subject competencies. Seven sub-elements were derived from each competency. Frequency analysis was performed to determine how often the sub-elements were reflected in the activity tasks. The results were as follows. First, with regard to the sub-elements of 'practical problem-solving capability', 'value judgment' was reflected most frequently in the activity tasks followed by 'exemplification of solution', 'logical thinking', 'critical thinking', 'decision-making', 'practical reasoning', and 'evaluation of solutions'. Secondly, the sub-elements of 'independent life capability' were unevenly distributed in the activity tasks. The 'capability to perform conscious living' was reflected most frequently followed by 'development and self-identity', 'time, money, and leisure management', and 'reasonable consumption and resource utilization'. For teachers wanting to teach activity-oriented classes and student participatory classes, the results pinpoint the materials necessary to develop learners' subject competencies by using textbooks from different publishing companies.

• Journal of Korean Society of Transportation
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• v.20 no.1
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• pp.111-119
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• 2002

One of the advantages of SP methods is the possibility of getting a number of responses from each respondent. However, when the repeated observations from each respondent are analysed by applying the simple modeling method, a potential problem is created because of upbiased significance due to the repeated observation from each respondent. This study uses a variety of approaches to explore this issue and to test the robustness of the simple model estimates. Among several different approaches, the Jackknife method and Kocurs method were applied. The Jackknife method was implemented using a program JACKKNIFE. The model estimate results of Jackknife method and Kocurs method were compared with those of the uncorrected estimates in order to test whether there was repeated measurement problem or not and the extent to which this problem affected the model estimates. The standard errors between the uncorrected model estimates and Jackknife estimates were also compared. The results reveals that the t-ratios of Kocurs are much lower than those of the uncorrected method and Jackknife estimates, indicating that Kocurs method underestimates the significance of the coefficients. Jackknife method produced the almost same coefficients as those of the uncorrected model but the lower t-ratios. These results indicate that the coefficients of the uncorrected method are accurate but that their significance are somewhat overestimated. In this study. 1 concluded that the repeated measurement Problem did exist in our data, but that it did not affect the model estimation results significantly. It is recommended that such a test should become a standard procedure. If it turns out that the analysis based on the simple uncorrected method are influenced by the repeated measurement problem. it should be corrected.

• Journal of Gifted/Talented Education
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• v.18 no.1
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• pp.1-21
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• 2008

The purpose of this study was to develop problem-solving inquiries for the science gifted and to analyze the effects of problem-solving inquiries. The problem-solving inquiries were composed of scientific knowledge, scientific inquiry skills and creative thinking. The problem-solving inquiries were applied to the science gifted attending the institute of the gifted education. The test of science-creative problem solving (TSCPS) was used to know effects of improvement of science-creativity and the result of TSCPS showed the improvement of science creativity. The analysis of student-student dialogues during experiments showed that the type of dialogue was different on the type of problem-solving inquiry. The dialogue of convergent thinking was frequently showed up on the problem-solving inquiry needed logical thinking whereas that of divergent thinking on the problem-solving inquiry needed idea generation. The problem-solving inquiries had a positive effects on the improvement of the science-creativity.