• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.384-388
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• 1997

Recently,direct rolling process has been drawing increasing interests because production cost be greatly reduced by eliminating subsequent hot rolling processes. Such a process has been characterized to prosuce thin steel strip (thickness 1~5mm) directly from molten metal and to skip over the conventional hot rolling processes. However, since there are several process parameters, which affect the quality of product,and their relationship between the parametersare very complex,it is therefore very difficult to realize the process design and the quality control. To overcome these difficulties quantitative relationship between the parameters are investigated through a numerical analysis. Form these results, it is found that solidification final point is the most important paramter which is critical to quality of the strip. Also,the multiple regression model is obtianed to determine their relationship from the solidification final point and roll separating force which can be easily estimated

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.2
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• pp.81-86
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• 2006

The machining parts must be produced within the specification of drawing and those will be able to meet function and efficiency. At that time, it is very important not only precision machine and machining technique but also the measurement technique. So, the improvement of measurement technique is to be joined together at once with improvement of machining technique. Finally, the quality and value of the parts are decided by precision measurement. This paper aims to study on the machined surfaces characteristics of aluminum alloy by AFM(Atomic force microscope) measurement. The objective is contribution to ultra-precision machining by exhibit foundation data of surface roughness and tool wear when parts are cutting with diamond tool at the factory.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.301-301
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• 2000

It is well known, for many years, that deep drawability ,can be improved by applying variable blank holding force. To apply variable blank holding force during cup during, we set up pressure controlling system on experimental hydraulic press, and the pressure control system is often called NC(Numerically Controlled} cushion system. Using the NC cushion system we carry out pressure control experiment and the proposed structure shows good performance. And we compare drawability of square steel cups with NC cushion and that with conventional cushion. The results show drawability is greatly improved when the pressure control curve is designed in a S-shaped curve. This paper includes design details of the NC cushion system and experimental analysis of drawability with experimental NC cushion system.

• The Journal of Korean Physical Therapy
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• v.14 no.3
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• pp.24-44
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• 2002

Traction has been used since ancient times in the treatment of painfull spinal conditions, but the literature on traction and its clinical effectiveness Is limited. Traction can be defined as a drawing or pulling tension applied to a body segment. Cervical traction is a technique that applies a longitudinal force of the cervical spine and associated structures. Goals of traction include reduction of radicular signs and symptoms associated with conditions such as disk protrusion, degenerative disk disease, lateral stenosis, muscle spasm, and subluxations. The various mechanical factors most relevant to cervical traction are organized and discussed. The factors presented are 1) angle of pull, 2) Traction force, 3) duration of traction, 4) neck position and clinical application, and 5) frequency of treatment. It should allow physical therapists to adjust traction protocol to match the patient's symptoms and diagnosis. The purpose of this study is to provide a comprehensive overview of the cervical traction and treatment guidelines.

• Transactions of Materials Processing
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• v.11 no.6
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• pp.513-518
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• 2002

The equivalent boundary conditions have been applied to the front door panel forming process, in order to demonstrate its reliability and validity. The elongation in the bead forming process is applied to the binder wrap process as the equivalent displacement boundary condition and the restraining force in the drawing process is applied to stamping process as the equivalent force boundary condition. The result calculated with the equivalent boundary conditions shows closer coincidence with the experimental result than simulation with different boundary conditions. The numerical result fully demonstrates that drawbead forming simulation for calculation of equivalent boundary conditions is necessary and effective.

• Transactions of Materials Processing
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• v.6 no.2
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• pp.152-160
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• 1997

Three-Dimensional finite element analysis is performed using PAM-STAMP for design evaluation of automotive back door inner panel die. Gravity process by blank own weigth, binder-wrap process, and drawing process in the forming operations are sequentially simulated with Virtual Manufacturing Method. The most valuable result in this research is that 3-D FEM analysis can be applied to the design evaluation of draw dies in the die try-out, though effects of mesh size and drawbead resistance force on the try-out, the experimental knowhows about the forming variables such as friction coefficient punch velocity, drawbead force, etc are necessary.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.3
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• pp.80-93
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• 1996

A 2-dimensional FEM/GEM program was developed under the plane strain assumption using linear line elements for analyzing stretch/draw forming operations of an arbitrarily shaped draw-die. FEM formulation adopted a new algorithm for solving force equilibrium as well as non-penetration condition simultaneously. Also, a rigid-viscoplastic material model with Hill's normal anisotropic yield condition and rate-sensitive hardening law is assumed, along with the Coulomb friction law in the contact regions. For the case of numerical divergence at nearly final forming stages, geometric force equilibrium method(GEM) is also introduced. The developed program was tested by simulating the forming processes of cylindrical punch/open die, and the drawing processes of automotive oilpan and hood inner panel in order to verify the usefulness and validity of FEM/GEM formulation. The numerical simulation verified the validity and robustness of developed program.

• The Journal of Korean Association of Computer Education
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• v.17 no.6
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• pp.103-113
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• 2014

This study designed and implemented a query model for consecutive analyses of dynamic multivariate graph data. First, the query model consists of two procedures; setting the discriminant function, and determining an alteration method. Second, the query model was implemented as a query system that consists of a query panel, a graph visualization panel, and a property panel. A Node-Link Diagram and the Force-Directed Graph Drawing algorithm were used for the visualization of the graph. The results of the queries are visually presented through the graph visualization panel. Finally, this study used the data of worldwide import & export data of small arms to verify our model. The significance of this research is in the fact that, through the model which is able to conduct consecutive analyses on dynamic graph data, it helps overcome the limitations of previous models which can only perform discrete analysis on dynamic data. This research is expected to contribute to future studies such as online decision making and complex network analysis, that use dynamic graph models.

• Physical Therapy Korea
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• v.24 no.1
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• pp.61-70
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• 2017

Background: Scapular winging is a prominence of the entire scapular medial border, mainly caused by insufficient activity of the serratus anterior (SA) and imbalance of scapulothoracic muscles. Push-up plus (PUP) exercise has been commonly used to increase SA muscle activity. The facilitation of abdominal muscle may affect scapular muscle activity by myofascial connections. Thus, the sequential activation of the turnk muscles is suggested to facilitate the transition of proper force from upper limb and restore force couple of scapular muscles. The abdominal drawing-in maneuver (ADIM) has been effective in improving activation of the deep trunk muscles during movement. Objects: The aim of this study was to determine the effect of ADIM on the activity of the upper trapezius (UT), lower trapezius (LT), and SA during PUP exercises in subjects with scapular winging. Methods: Fourteen men with scapular winging (determined as a of distance between the scapular medial border and thoracic wall over 3 cm) volunteered for our study. The subjects performed the PUP exercise with and without ADIM. Surface electromyography was used to collect the electromyography data of the UT, LT, and SA. A scapulometer was used to measure the amount of scapular winging. Results: SA activity was significantly greater and scapular winging significantly lower during the PUP exercise with ADIM than during those without ADIM. Conclusion: PUP exercise with ADIM can be used as an beneficial method to improve SA activation and to reduce the amount of scapular winging in subjects with scapular winging.

• Journal of The Korean Association For Science Education
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• v.24 no.4
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• pp.785-801
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• 2004

A Typically-Perceived-Situation(TPS) is a situation which might be useful for conceptual learning of science, rising spontaneously in an individual's mind when someone is thinking about, or in relation to, any object such as physical object, concept, situation, etc. But, for a discussion about the TPS' usefulness in depth, we need to analyze the specific features of the TPS in relation to conceptual learning of science. This study investigated four elementary school students' TPSs related to the topic of the action of force, especially (a) 'the situation where force is being acted on an object', and (b) 'the situation where force is not being acted on an object', with an interview as well as with a drawing-and-explanation type questionnaire. Their TPSs were then compared with their concepts, checked by a misconception questionnaire of choice-and-explanation type. The results showed that the students' TPSs illustrated not only their conceptions about the action of force, but also gave more fruitful details of their ideas, including (a) clues of their conceptions, (b) concrete situations, and (c) their past experiences with emotional components. On the whole, the TPS's appeared to be rather stable, affected by their past experiences, and needed to be analyzed into their sub-units for more subtle details. Finally, some practical ways of how to apply the ideas of the TPS to the conceptual learning of science are suggested.