• International Journal of Railway
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• 제2권2호
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• pp.70-79
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• 2009

An optimal driving strategy of a train in a long journey on a nonsteep track has four phases: an initial power phase, a long hold speed phase, a coast phase and a final brake phase. The majority of the journey is speed holding. On a track with steep gradients, it becomes necessary to vary the strategy around steep sections of track because it is not possible to hold a constant steep on steep track. Instead we must interrupt the speed hold phase with a power phase. The aim of this paper is to show that there is a unique power phase that satisfies the necessary conditions for an optimal journey. The problem is developed and solved for various cases, from a simple single steep gradient to a complicated multiple steep gradient section. For each case, we construct a set of new conditions for optimality of the power phase that minimises the energy used during the power phase subject to a weighted time penalty. We then use the new necessary conditions to develop a calculate scheme for finding an optimal power phase for a steep incline. We also present an example to confirm the uniqueness of an optimal power phase.

• Structural Engineering and Mechanics
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• 제50권3호
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• pp.403-417
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• 2014

The present paper addresses a general formulation for the thermo elastic analysis of a functionally graded cylindrical shell subjected to external loads. The shear deformation theory and energy method is employed for this purpose. This method presents the final relations by using a set of second order differential equations in terms of integral of material properties along the thickness direction. The proposed formulation can be considered for every distribution of material properties, whether functional or non functional. The obtained formulation can be used for manufactured materials or structures with numerical distribution of material properties which are obtained by using the experiments. The governing differential equation is applied for two well-known functionalities and some previous results are corrected with present true results.

• 아동학회지
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• 제29권6호
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• pp.163-176
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• 2008

The purpose of this study was to develop a standardized performance style Multiple Intelligences Test for preschoolers(MIT-P). A total of 270 preschoolers(3~5-years-old) participated in this study. Tools and procedures were developed to measure performance in 7 areas of multiple Intelligences(linguistic, mathematical, science, social, music, art and kinesthetic). The final test set included 138 items. Reliability of the MIT-P was relatively high(Cronbach alpha =.92). Intercorrelations among measures of the 7 areas indicated construct validity. Based on these results, the pilot study of MIT-P is considered adequate to form the basis of a new test that would help teachers and parents to identify children's strengths and weaknesses and may be useful for educational planning.

• 영어어문교육
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• 제11권1호
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• pp.179-202
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• 2005

The purpose of this study is to examine whether the teacher feedback (TF) group and the peer feedback (PF) group exhibit significant differences in their English writing abilities and attitudes toward English writing. The subjects of this study are eighty-three college first-year students enrolled in a college English reading class. The subjects' first and final writing samples are used to measure the improvement of English writing abilities and a set of pretest and posttest questionnaires is administered in order to find their attitudes. The qualitative and quantitative analyses of the data collected show the following results. First, the two groups show no significant difference in their holistic scores. Neither do the two groups display any significantly different development in their analytic scores. Second, the two groups show no significant differences in attitude factors but writing confidence. These findings suggest that peer feedback can be used to encourage EFL college students to develop their writing abilities.

• 제어로봇시스템학회논문지
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• 제10권12호
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• pp.1181-1188
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• 2004

This paper reviews the main aspects of cardiovascular system dynamics with emphasis on modeling hemodynamic characteristics using a lumped parameter approach. Methodological and physiological aspects of the circulation dynamics are summarized with the help of existing mathematical models: The main characteristics of the hemodynamic elements, such as the heart and arterial and venous systems, are first described. Lumped models of micro-circulation and pulmonary circulation are introduced. We also discuss the feedback control of cardiovascular system. The control pathways that participate in feedback mechanisms (baroreceptors and cardiopulmonary receptors) are described to explain the interaction between hemodynamics and autonomic nerve control in the circulation. Based on a set-point model, the computational aspects of reflex control are explained. In final chapter we present the present research trend in this field and discuss the future studies of cardiovascular system modeling.

• Transactions on Control, Automation and Systems Engineering
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• 제2권1호
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• pp.62-68
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• 2000

Fixtures are used in almost all phases of machining and assembly to position and hold a part accurately. The class of fixture which consists of 3 locators and 1 clamp(3L/1C) is known as the minimal set that can provide form closure which is a kinematic constraint condition for preventing all planar motions. This type of fixtures has advantages in terms of the number of fixture elements required, the time for clamping, and so on. However it is not widely used in industry because reliable loading scheme has not been reported. In this paper, we propose a method to load the class of 3L/1C fixtures using compliant motions. The planner is developed for synthesizing compliant motions to achieve precise final fixture configuration in the presence of sensing and control uncertainties. A novel approach to eliminate uncertainty in part orientation by adding one extra fixture element called an aligning pin is proposed.

• Bulletin of the Korean Chemical Society
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• 제25권4호
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• pp.553-556
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• 2004

In this study we have performed ab initio computer simulations to investigate the conformational characteristics of the tetraethyl (1) and triethyl ester (2) of p-tert-butylcalix[4]arene. The structures of different conformational isomers for each compound have been optimized using ab initio RHF/6-31G methods. After optimization, B3LYP/6-31+G(d,p) single point calculations of the final structures are done to include the effect of electron correlation and the basis set with diffuse function and polarization function. Relative stability of tetraethyl ester (1) of p-tert-butylcalix[4]arene is in following order: cone (most stable) > partial cone > 1,3- alternate > 1,2-alternate isomer. Relative stability of triethyl ester (2) of p-tert-butylcalix[4]arene is in following order: cone (most stable) > 2-partial cone > 1-partial cone > 3-partial cone ~ 1,3-alternate ~ 1,2- alternate isomer.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
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• pp.225-233
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• 2004

Deployable structures are space frames consisting of straight bars that are linked together into bundle and can be deployed large, load bearing structures. Deployable structures are easy to set up, to assemble, to disassemble, to transport and to keep for the use. Also, reusability and flexibility are another important advantages for environmental matter. Since deployable structures have various advantages, they offer viable alternatives for a wide range of potential applications in the temporary construction industry as well as in the aerospace industry, The purpose of this thesis is to decide on geometrical parameters of the design through the numerical analysis and create a final configuration of deployable structures using the geometrical parameters. The Multibody Dynamic Analysis that is dealt with mechanics and aeronautics is used for the method of analysis.

• 한국컴퓨터정보학회논문지
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• 제22권2호
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• pp.21-27
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• 2017

In this paper, we propose a pupil detection method using PCA(principal component analysis) and Hough transform. To reduce error to detect eyebrows as pupil, eyebrows are detected using projection function in eye region and eye region is set to not include the eyebrows. In the eye region, pupil candidates are detected using rank order filter. False candidates are removed by using symmetry. The pupil candidates are grouped into pairs based on geometric constraints. A similarity measure is obtained for two eye of each pair using PCA and hough transform, we select a pair with the smallest similarity measure as final two pupils. The experiments have been performed for 1000 images of the BioID face database. The results show that it achieves the higher detection rate than existing method.

• 한국군사과학기술학회지
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• 제18권3호
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• pp.316-325
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• 2015

This paper describes the design guide and its assessment process to be applied to the launcher vehicle exterior design. A launcher vehicle design is required to meet three kinds of design attributes; symbolic quality, usability, and aesthetic quality. The launcher vehicles referred to in this paper are assessed by the elements in the guidelines. A set of assessment process and methods is derived to evaluate how well the three design attributes are applied in the actual launch vehicle design. An example of assessment is shown at the last part of this paper. By this way designers can take various criteria into account integratively and select the final design. High design satisfaction and pride of the operators and the nation can be assured in the end.