• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.12
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• pp.2101-2109
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• 2003

Structural shape optimization offers engineers with numerous advantages in designing shapes of structures. However, excessive relocation of nodes often cause distortion of elements and eventually result in degrade of accuracy and even halts of processes. To overcome these problems, an effective method, Selective Element Method(SEM), has been developed. This paper describes the basic concept of SEM and processes to implement into real-world problem. 2-D and 3-D shape optimization problems have been chosen to show the performance of the method. Though some limitations have been found, it was concluded that SEM can be useful in general shape optimization and even in some special cases such as decision of optimal weld line location.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.709-712
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• 2003

The existing technical limitation makes engineer imitate nature to solve engineering problems. Recently Micro Air Vehicle(MAV) imitating the mechanism of birds or insects is being developed. Especially Ultra Flite supported by DARPA is studying hummingbird aerodynamics to relate that information to MAV. To drive MAV bender piezoelectric(PZT) actuators are used due to the convinience of control and the small size. But the displacement of the PZT actuators are very small, and the wing driving mechanism which amplifies the stroke generated by the PZT actuators has constraints in design and manufacture because of the small dimension. In this paper a wing design concept and a efficient driving mechanism are proposed. Electroactive polymers(EAPs) are used as wing mechanism actuators. Using OpenGL the mechanisms are simulated graphically. Also a prototype actuator is being developed and verified by digital Mockup with CATIA. Basic kinematics of the mechanism is studied.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.151-154
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• 2007

The purpose of this study is to identify the basic concept of thruster design through the visualization firing test on a hydrazine thruster. We designed the visual catalyst bed on the basis of the 1lbf hydrazine thruster for a low earth orbit satellite and observed visually the internal catalyst bed reaction.

• Journal of TMJ Balancing Medicine
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• v.2 no.1
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• pp.13-16
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• 2012

Objectives: The quadrant theorem is a theorem proposed by C. M. Guzay in the field of functional, holistic dentistry. There are not much of scientific literature on the quadrant theorem. This study briefly reviewed basic concepts of quadrant theorem. Methods: A publication by Guzay and research articles were searched and reviewed. The quadrant theorem is depicted as a series of illustrations and accompanied explanations. Results: The primary concept of the quadrant theorem was presented in 1952. Based on geometric biophysics of the occlusion and related anatomical functions, physiological pivotal axis of the mandible is analyzed to occurs at the dens (the sub-atlas area). Composite muscular activity links the mandibular posture with C1-C2, which is then linked with the spinal posture. Twenty illustrations are progressively presented on the physiognomy, occlusion, and analysis of anatomical functions. The balanced distribution of the forces gives the durability of the functions in life. Conclusions: The quadrant theorem provides a functional linkage between the mandibular posture and the upper cervical vertebrae.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.200-205
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• 1992

The classical control theory has been developed successfully for the design of a system controller and has evolved continually. Even though sophisticated simulation techniques and software packages are available, there is still some difficulty in the design of a complex system controller at the desk. So the trial and error method is sometimes used to design a new controller, but it requires excess time and cost. This paper suggests a controller design method through the experimental approach. The basic concept is to adjust gradually the design parameters of the controller to the simulation results and experimental data of a similar real system. This method will be a very useful and easy way to design an accurate and/or optimal controller for a real plant while reducing time and giving a good solution at a reasonable cost.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.10a
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• pp.98-105
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• 1993

A method for shape design sensitivity analysis for axisymmetric shells of general shapes is developed. The basic approach is to divide the structures into many segments. For each of the segments, the formula for a shallow arch or shell can be applied and the results assembled. To interconnect those segments, the existing sensitivity formula, obtained for a variation only in the direction perpendicular to the plane on which the structure is mapped, has been extended to include a variation normal to the middle surface. The method follows the adjoint variable approach based on the material derivative concept as established in the literature. Numerical examples are taken to illustrate the method and the applicability to practical design problems.

• Journal of Sasang Constitutional Medicine
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• v.15 no.3
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• pp.62-73
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• 2003

Lee, Jema recognized human being as human figure and human nature according to 'if threre is a thing, there are a law to explain the thing'. And he thought Sa-Sang is the most basic and proper concept to explain things and changes. This paper is to find his medical view why human beings are classified into four types. 1. A medical clue to classify human being is different viscera function. 2. The size of viscera means the strength and weakness of metabolic function of viscera. 3. The essence of different viscera function is related to metabolism of water and food, air and fluid. Lungs and Liver do metabolic function through exhale and inhale of air and fluid. Spleen and Kidneys do metabolic function through intake an d output water and food. 4. It is most important to consider and to treat the condition of small size viscera.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.91-96
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• 2001

Diminishing fare rate to distance is widely applied in transportation field including bus, but the decision method of diminishing rate is not established. The basic concept of diminishing fare rate to distance is that passengers have a benefit according to their travel distance. Furthermore, this can be justified in the standpoint of operator because the cost of long-distance traveller is lower than that of short-distance traveller to make same income. It is essential to introduce diminishing fare rate to distance to decide diminishing rate. We suggested methodologies regarding how to decide diminishing rate on the basis of operator costs.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.226-234
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• 2000

The friction stir welding technique is a derivative of conventional friction welding, which enables the advantages of solid-phase welding to be applied to the fabrication of long butt and lap joints, with very little postweld distortion. Friction stir welding is a remarkable new welding technique for joining aluminum alloys and has the potential for welding other ferrous materials. It has already been developed beyond a laboratory curiosity and has been proved as a potential practical welding technique offering low-distortion, high-quality, low-cost welds from simple concept machine tool welding equipment. To bring this remarkable method of welding aluminum alloys to the attention of Industry, this article introduces the basic principle of friction stir welding, pointing out the practical advantages and most important of all, describes the exceptionally good metallurgical and mechanical properties.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.1
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• pp.64-79
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• 2017

This study was to evaluate the suitability of scientific questions as qualification examination for high school graduation by content validity and item response with three examinees and two preliminary examinees. As a result, scientific questions were concentrated on two units of six units of total, and application appeared to be lacking problem area by 8% compared to understanding and application. Examinees and preliminary examinees chose correct answers most by hap or guess, sometimes by experience or common sense, and the least by scientific concept. In addition, they could chose correct answers by hap or guess because there were words that implied the correct answer in questions and answers, or because they could compared and/or analyzed questions and answers. With these results, two proposals were suggested as follows; (1) scientific questions of qualification examination for high school graduation should measure basic scientific literacy. (2) specific criteria for science literacy in qualification examination for high school graduation should be set.