• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.3 s.96
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• pp.259-265
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• 2005

A two-degree-of-freedom out-of-plane model with contact stiffness is presented to describe dynamical interaction between the pad and disc of a disc brake system. It is assumed that the out-of-plane motion of the system depends on the friction force acting along the in-plane direction. Dynamic friction coefficient is modelled as a function of both in-plane relative velocity and out-of-plane normal force. When the friction coefficient depends only on the relative velocity, the contact stiffness has the role of negative stiffness. The results of stability analysis show that the stiffness of both pad and disc is equally important. Complex eigen value analysis is conducted for the case that the friction coefficient is also dependent on the normal force. The results further verify the importance of the stiffness. It has also been found that increasing the gradient of friction coefficient with respect to the normal force makes the system more unstable.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.629-630
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• 2011

• Journal of Power System Engineering
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• v.16 no.4
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• pp.17-23
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• 2012

In this study, the numerical simulation and basin model test have been performed to evaluate sea worthiness and resistance performance for a small pre-planning three type of leisure boats which are U, V, Y shapes of hull forms. As a well known commercial CFD code, Maxsurf, was applied for modeling hull forms used as the solver of motion analysis. Also the model resistance test was carried out to estimate the effective power of boat in the basin tank. Numerical simulation and model test results show that Y-shaped hull is better than the other types in terms of heave and pitch motion, having a key effect on a boat sea worthiness. But V-type hull is more efficiency than others cases in resistance performance.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.259-264
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• 2011

Authors are carrying out a national project which develops an accuracy simulation technology of mechanical machines to predict the stiffness and accuracy of machine components or entire machine in the design stage. Analysis methods in this technology are generalized to achieve the wide applicability and to be utilized as a web based platform type. In this paper, outline of the project such as concept, aim and configuration is introduced. Contents of the research are also introduced, which are composed of four main research fields; structural dynamics, linear motion analysis, rotary motion analysis and control and vibration analysis. Finally, a future plan is presented which is made up with three stages for the advance toward an ultimate manufacturing tools.

• The Journal of Korea Robotics Society
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• v.17 no.4
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• pp.417-424
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• 2022

In this paper, the developed trunk cargo unloading automation system is introduced, and the RGB-D sensor-based box loading situation recognition method and unloading plan applied to this system are suggested. First of all, it is necessary to recognize the position of the box in a truck. To do this, we first apply CNN-based YOLO, which can recognize objects in RGB images in real-time. Then, the normal vector of the center of the box is obtained using the depth image to reduce misrecognition in parts other than the box, and the inner wall of the truck in an image is removed. And a method of classifying the layers of the boxes according to the distance using the recognized depth information of the boxes is suggested. Given the coordinates of the boxes on the nearest layer, a method of generating the optimal path to take out the boxes the fastest using this information is introduced. In addition, kinematic analysis is performed to move the conveyor to the position of the box to be taken out of the truck, and kinematic analysis is also performed to control the robot arm that takes out the boxes. Finally, the effectiveness of the developed system and algorithm through a test bed is proved.

• Journal of Korean Physical Therapy Science
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• v.4 no.2
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• pp.373-382
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• 1997

This study has been aimed at figuring out the fact that four kinds of body type grouped according to the tilting of scapular of upper extremity and ilium of low extremity showed the mobility increase for joint parts and the limitation. When we make a thrapy plan which should be comprehensive and general in preventative management and therapy. For the sake of patients who have spinal disabilities including low back pains, it is required for many joints distributing among upper and lower extremity to have hypermobility and hypomobility based on regulation. So, this study was conducted to establish a standard for the effective pattern of hypermobility or hypomobility. I hope that the result of this study can help support the practics of physical therapy as a part of scientic method. Especially I think it will be able to be conductive to those who major in physical therapy on the arthrogenic region.

• Journal of Fisheries and Marine Sciences Education
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• v.15 no.2
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• pp.184-192
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• 2003

When the present Learning System for Computer-Related Subjects Using WBI is implemented on the Web with the above characteristics to help students to study computer subjects without any limitations of time or space, they can easily attain the goals of learning, have computer-utilizing abilities or information capacity, and enhance their capabilities for self-initiative learning. This system enables the learners to carry out 'plan-do-see' for the contents of learning initiatively. The learners can study the practice part of the curriculum using multi-media, such as motion pictures, voices, images, and sound effects, vividly with a sense of actual presence. It helps the students to have an active attitude toward leaning afterward. without meeting the teacher or without any storage media, the leaners can submit their assignments or materials for performance evaluation via the Internet.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.6
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• pp.439-446
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• 2022

Efforts to reduce carbon dioxide(CO₂) emissions are being carried out due to climate environmental problems. Eco-friendly ships are also being developed, and various energy saving measures have been developed and applied. In ships, researches have been conducted in various fields such as electric propulsion system and energy saving devices. In addition, the development of ships using various renewable energy, such as kite using wind power and wind power generation, has been carried out. This paper proposes a plan to use renewable energy for ships by applying wave generators to small ships. In 2016, 130 small domestic ships drifted by sea due to discharge of starting storage batteries, and discharge cases accounted for the largest portion of the causes of domestic ship accidents. This is due to the excessive use of storage batteries for starting the main engine by departing in a weak storage battery state for small ships. Accordingly, two type wave power generators - opened flow wave power generator and enclosed vibrator type wave power generator - are developed for charging a starting storage battery when the ships are stationary at sea or port. Opened flow wave power generator utilizes the flow of fluid in the ship by using wave induced ship motion. Enclosed vibrator type wave power generator utilizes the pendulum kinetic energy located in a ship due to wave induced ship motion.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.161-165
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• 2008

The purpose of this study is to design and apply that teaching and learning methodology of motion image based on modified ASSURE model to improve creativity the competitive power of an information oriented society. To accomplish the end of this study, the following procedure and methods were performed. After the theoretical consideration about education visual image and creativity, we get to the bottom the connection of them. In the result of that, it designed plans for teaching and learning applied by modified ASSURE model. And it had larger efficiency to apply a creativity develop learning model when it spread out teaching and learning process to produce motion image. The main points of the result and the meaning are as follows. Firstly, in the light of the result of this study, student's creativity were enhanced to a large extent as applying this study. It appeared that the average of performance improved from 30.18 to 37.44. Such difference was t=-14.39 (p<0.05), which is a meaningful difference in terms of statistics. Secondly, it laid the foundations for being cultural prosumer as applying this study. Additionally, it anticipated that all the students join in this study become leader group in the age of digital media.

• Journal of The Korean Association For Science Education
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• v.8 no.1
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• pp.43-55
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• 1988

This study intended to find the differences between expert's and novice's thinking processes when they solve physics problems. Five physics professors and twenty sophomore students in a physics department were participated in the study. The researcher investigated their thinking processes in solving three physics problems on NEWTON's law of motion. The researcher accepted so called "Thinking Aloud" method. The thinking processes were recorded and transfered into protocols. The protocols were analysised by problem solving process coding system which was developed by the researcher on the basis of Larkin's problem solving process model. The results were as follows: (1) There was no difference of time required in solving physics problem of low difficulty between expert and novices; but, it takes 1.5 times longer for novices than experts in solving physics problems which difficulties are high and average. (2) Novices used working forward strategy and working backward strategy at the similiar rate in solving physics problems which difficulties were average and low. while Novices mo mostly used working backward strategy in solving physic problems which difficulty was high. Experts mostly used working forward strategy in solving physics problems whose difficulties was average and low, however experts used working forward strategy and working backward strategy at the similiar rate in solving physics problem which difficulty was high. (3) Novices usually wrote only a few information on the diagram of figure they drawn, on the other hand experts usually wrote almost all the information which are necessary for solving the problems. (4) Experts spent much time in understand the problem and evaluation stage than novices did, however experts spent less time in plan stage than novices did. (5) Physics problems are solved in sequence of understanding the problem, plan, carrying out the plan, and evaluation steps regardless of problem difficulty.