• Communications of Mathematical Education
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• v.18 no.2 s.19
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• pp.265-276
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• 2004

In this study we in detail analyze Kolmogorov's viewpoint of mathematical abilities, and conclude that school geometry plays important role in developing and upbringing mathematical abilities. We discuss meanings of school geometry in gifted students education, and draw didactical principles concerned with gifted students education. We suggest some geometrical materials which aim for developing and upbringing mathematical abilities.

• Korean Journal of Childcare and Education
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• v.1 no.1
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• pp.37-58
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• 2005

The purpose of this study was to examine whether or not the use of number-related fairy tales had any effects on young children's mathematical inquiry skills in a bid to help facilitate their development of mathematical capabilities. The subjects in this study were 30 preschoolers who were four years old in Western age and attended G kindergarten in Jung-gu, Ulsan. The instrument used to assess their mathematical inquiry skills was Choi Hye-jin(2003)'s Preschooler Math Capability Inventory. The collected data wee analyzed with SPSS Win 11.5 program, and analysis of covariance was utilized. The findings of the study were as follows: The application of number-related fairy tales turned out to be effective in developing the young children's abilities to figure out the regularity of things, conception of number, geometrical abilities, measurement abilities and mathematical inquiry skills of the preschoolers. The above-mentioned findings suggested that the application of number-related fairy tales was one of good teaching methods to step up the development of young children's mathematical inquiry skills. Specifically, that could inner motivation to preschoolers in mathematical contexts and take their problem-solving skills to another level.

• Structural Engineering and Mechanics
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• v.48 no.6
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• pp.849-878
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• 2013

This paper consists of two parts, which broadly examines solution techniques abilities for the structures with geometrical nonlinear behavior. In part I of the article, formulations of several well-known approaches will be presented. These solution strategies include different groups, such as: residual load minimization, normal plane, updated normal plane, cylindrical arc length, work control, residual displacement minimization, generalized displacement control, modified normal flow, and three-parameter ellipsoidal, hyperbolic, and polynomial schemes. For better understanding and easier application of the solution techniques, a consistent mathematical notation is employed in all formulations for correction and predictor steps. Moreover, other features of these approaches and their algorithms will be investigated. Common methods of determining the amount and sign of load factor increment in the predictor step and choosing the correct root in predictor and corrector step will be reviewed. The way that these features are determined is very important for tracing of the structural equilibrium path. In the second part of article, robustness and efficiency of the solution schemes will be comprehensively evaluated by performing numerical analyses.

• Advances in aircraft and spacecraft science
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• v.4 no.4
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• pp.371-399
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• 2017

The motion of propeller driven airplanes, flying at constant speed on ascending or descending helical trajectories is analyzed. The dynamical abilities of the airplane are shown to result in restrictions on the ranges of the geometrical parameters of the helical path. The physical quantities taken into account are the variation of air density with altitude, the airplane mass change due to fuel consumption, its load factor, its lift coefficient, and the thrust its engine can produce. Formulas are provided for determining all the airplane dynamical parameters on the trajectory. A procedure is proposed for the construction of tables from which the flyability of trajectories at a given angle of inclination and radius can be read, with the corresponding minimum and maximum speeds allowed, the final altitude reached and the amount of fuel burned. Sample calculations are shown for the Cessna 182, a Silver Fox like unmanned aerial vehicle, and the C-130 Hercules.

• School Mathematics
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• v.13 no.1
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• pp.1-17
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• 2011

This study investigated the Chinese national university entrance examination (Gaokao) in mathematics administered in 2009 and 2010 to draw out some implications on the College Scholastic Ability Test (CSAT) in mathematics of Korea. To evaluate the attainments of basic mathematical skills and multilateral abilities required for further studies in university, the Gaokao mathematics is set in two forms(Art/Science), based on the Chinese national mathematics curriculum. The types of items in the Gaokao mathematics are multiple-choice, single-answer, and write-out-answer. The mathematical abilities that the Gaokao mathematics evaluates are mathematical reasoning, operation, geometrical imagination, application, and creativity. As a result, some implications on the Korean CSAT are drawn out in terms of the level of difficulty, the types of items, the arrangements, and the scores of items.

• Advances in aircraft and spacecraft science
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• v.5 no.1
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• pp.73-105
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• 2018

A particular type of constant speed helical trajectory, with variable ascension rate, is proposed. Such trajectories are candidates of choice as motion primitives in automatic airplane trajectory planning; they can also be used by airplanes taking off or landing in limited space. The equations of motion for airplanes flying on such trajectories are exactly solvable. Their solution is presented, together with an analysis of the restrictions imposed on the geometrical parameters of the helical paths by the dynamical abilities of an airplane. The physical quantities taken into account are the airplane load factor, its lift coefficient, and the thrust its engines can produce. Formulas are provided for determining all the parameters of trajectories that would be flyable by a particular airplane, the final altitude reached, and the duration of the trajectory. It is shown how to construct speed interval tables, which would appreciably reduce the calculations to be done on board the airplane. Trajectories are characterized by their angle of inclination, their radius, and the rate of change of their inclination. Sample calculations are shown for the Cessna 182, a Silver Fox like unmanned aerial vehicle, and the F-16 Fighting Falcon.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.1
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• pp.7-12
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• 2008

The vacuum interrupter (VI) is used for medium-voltage switching circuits due to its abilities and advantages as a compacted environmental friendly circuit breaker. In general, the application of a sufficiently strong axial magnetic field (AMF) permits the arc to be maintained in a diffused mode to a high-current vacuum arc. A full understanding of the vacuum arc physics is very important since it can aid to improve the performance of vacuum interrupter. In order to closely examine the vacuum arc phenomena, it is necessary to predict the magnetohydrodynamic (MHD) characteristics by the multidisciplinary numerical modeling, which is coupled with the electromagnetic and hydrodynamic fields, simultaneously. In this study, we have investigated the effect of changing geometrical parameters for electromagnetic behaviors of high-current vacuum arcs with two different types of AMP contacts, which are coil-type and cup-type, using a commercial finite element analysis (FEA) package, ANSYS. The present results are compared with those of MAXWELL 3D, a reliable electromagnetic analysis software, for verification.

• International Journal of Control, Automation, and Systems
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• v.4 no.2
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• pp.204-216
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• 2006

Latest advances in hardware technology and state of the art of mobile robot and artificial intelligence research can be employed to develop autonomous and distributed monitoring systems. And mobile service robot requires the perception of its present position to coexist with humans and support humans effectively in populated environments. To realize these abilities, robot needs to keep track of relevant changes in the environment. This paper proposes a localization of mobile robot using the images by distributed intelligent networked devices (DINDs) in intelligent space (ISpace) is used in order to achieve these goals. This scheme combines data from the observed position using dead-reckoning sensors and the estimated position using images of moving object, such as those of a walking human, used to determine the moving location of a mobile robot. The moving object is assumed to be a point-object and projected onto an image plane to form a geometrical constraint equation that provides position data of the object based on the kinematics of the intelligent space. Using the a priori known path of a moving object and a perspective camera model, the geometric constraint equations that represent the relation between image frame coordinates of a moving object and the estimated position of the robot are derived. The proposed method utilizes the error between the observed and estimated image coordinates to localize the mobile robot, and the Kalman filtering scheme is used to estimate the location of moving robot. The proposed approach is applied for a mobile robot in ISpace to show the reduction of uncertainty in the determining of the location of the mobile robot. Its performance is verified by computer simulation and experiment.