• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.658-666
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• 1992

In developing computer-aided design technology for optimization of stamping die design, it has been an important issue to treat the frictional constraint acting on the blank holder surface. The main goal of this work is to establish database of draw bead restraint force and clarify friction characteristic for various automotive sheet steels, which is essential in developing friction algorithm that can be used for CAD of stamping die design. Draw bead friction tester is used to evaluate the various parameters that affect the draw restraint force and the coefficient of friction for the cold rolled and the coated sheet steels such as drawing rate, lubricant type, surface property of material, etc.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.71-76
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• 2001

This paper describes a research work of developing system for conceptual die design system for Fine blanking. The method of approaching to the system is based on the knowledge-based rules. Knowledge for the system is formulated from experimental results and the empirical knowledge of field experts. This system has been written in VisualLISP on the AutoCAD using a personal computer and in Microsoft Visual Basic ver.6.0. Transference of data is accomplished by DXF (Drawing Exchange Format) method. This system consists of six modules, which are cognition of a drawing, cognition of shear length, calculation of shear force, materials properties database, determination of degree of difficulty of the product, determination of approximate life of punch and die modules. Results carried out in each module will provide efficiency to the designer and the manufacturer of die for Fine blanking. But the main focus of this system is the design of die for Fine blanking in the level of general concept. In order to use powerful tool in this field, developed system will be studied continuously.

• Transactions of Materials Processing
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• v.32 no.4
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• pp.199-207
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• 2023

The stainless steel basket-bowl, a critical component of washing machines, is characterized by its unique two-tiered circular shape. This study explores the potential of a draw-bead free die design to address tearing concerns in the prospective plastic layer during the drawing operation. In order to prevent wrinkles that may arise from the absence of a draw-bead, a two-stage punch configuration is proposed. The influence of the blank holder force on wrinkle reduction is also examined. Finite element analysis is employed to evaluate the proposed die design by analyzing the wrinkle shape and strain mode. The results confirm that the stainless steel basket-bowl can be successfully drawn without wrinkles utilizing the proposed two-stage punch without a draw-bead on the blank holder. These findings contribute to the development of more efficient and reliable manufacturing processes for the stainless steel basket-bowl production.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.239-246
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• 2018

In this study, we analyzed the balance of the both legs and the kinematic analysis of the upper limb segments and joints during archery shooting and compared the differences according to the scores. 9 K-university elite archery athletes participated. Each archer was asked to shoot 3-shots and 5-ends on a 122 cm target at a distance of 70 m. Seven infrared cameras (Qualisys, sweden) and two force plates (Kistler, Switerland) were used to calculate the upper limb segments and joint movements and the center of pressure (COP). When the archers shot 8 points, range of motion of elbow joint angle on drawing-arm and mediolateral COP range of motion on the left foot were larger than when 9-10 points were shot (p<.05). In order to maintain a high score in the archery game, constant balance is required, and the balance of the left foot supporting the bow during the shooting is an important factor. In addition, minimizing elbow joint movement of the drawing-arm supporting the bow will help stabilized shooting.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1643-1646
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• 2003

Drawing is a mechanical operation that attenuates thick material to an appropriate thickness for the next processing or end usage. When the input material has the form of a bundle or bundles made of very thin and long shaped wire or fibers, this attenuation operation is called "bundle drawing" or "drafting" Drafting is being used widely in manufacturing staple yarns. which is indispensable for the textile industry. However, the bundle processed by this operation undertake more or less defects in the evenness of linear density. Such irregularities cause many problems not only for the product quality but also for the efficiency of the next successive processes. Since long there have been many researches tying to find out factors affecting the irregularity of linear desity, to obtain optimal drafting conditions, to develop efficient measuring and analysis methods of linear density of bundle, etc., but there exists yet no fundamental equation describing the dynamic behavior of the flowing bundle during processing. In this research a mathematical model for the dynamic behavior of the bundle fluid is to be set up on the basis of general physical lows representing physical variables, i.e. linear density and velocity as the dynamic state of bundle. The conservation of mass and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basis of the simplified model, the simulation was performed and the results could be confirmed by the experiments under various conditions.

• The Journal of Korean Physical Therapy
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• v.27 no.3
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• pp.147-153
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• 2015

Purpose: The purpose was to determine whether the application of the abdominal drawing-in maneuver (ADIM) and abdominal expansion maneuver (AEM) to stroke patients would affects their trunk stability, balance, pulmonary function, and grip strength. Methods: The subjects were 36 stroke patients who were randomly and equally assigned to an ADIM group (n=12), an AEM group (n=12), and a control group (n=12). The intervention was applied to each group three times per week, 30 minutes each time, for four weeks. Outcome measures were grip strength, modified functional reach test (mFRT) and pulmonary function. Pulmonary function were measured force expiratory volume at one second (FEV1), forced vital capacity (FVC), FEV1/FVC and peak expiratory flow (PEF) values. Results: The results of the three groups showed statistically significant improvements in grip strength. The AEM group showed significantly greater differences in grip strength than either the ADIM group or the control group. In the anterior mFRT, the ADIM group showed significantly improvements than the control group. The ADIM and AEM groups were showed statistically significant greater improvements in PEF between the baseline and post-intervention and the post-analysis revealed that the AEM group showed significantly greater improvements than the control group. Conclusion: The results of this study indicate that the ADIM and AEM were effective in improving the PEF of pulmonary function. The ADIM was more effective than AEM in trunk stabilization.

• Physical Therapy Korea
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• v.18 no.4
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• pp.26-33
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• 2011

The aim of this study was to investigate the effects of respiratory muscle training (RMT) with abdominal drawing-in maneuver (ADIM) on pulmonary function. Twenty-two subjects with restrictive breathing participated in this study. All the subjects were randomly assigned to three groups (7 subjects in RMT group, 7 subjects in RMT with ADIM group, 8 subjects in control group). The first group performed the RMT by using incentive respiratory spirometer (IRS). The second group performed the RMT by using IRS and the ADIM by using a Stabilizer. The exercises were conducted over four days. The pulmonary function was evaluated using the spirometer to measure the force exploratory volume in 1 second ($FEV_1$) and forced vital capacity (FVC). Measurements were conducted on the first day and the last day. A paired-t test was used for pre-post changes and the change rates in FVC and $FEV_1$ among each group were investigated by a one-way ANOVA. The findings of the the study were as follows: 1) There were significant differences of FVC and $FEV_1$ between pre and post in the two training groups (p<.05) 2) There was no significant difference of the change ratio the FVC and $FEV_1$ between the RMT group and RMT with ADIM group. Therefore, it is concluded that respiratory muscle and ADIM training, combined with two methods of treatment would suggest positive evidence for improving pulmonary function.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.692-696
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• 2017

The shape of press components is becoming increasingly complex due to customer demands, process shortening and cost savings. In addition, the stability of the pressing process frequently varies during mass production due to the influence of many factors. In order to ensure the process stability, it is necessary to establish a process in which reproducibility is realized in tolerance, which is sufficient for advance study of shape, material, press, mold and lubrication. However, unforeseen changes in process parameters cause disruptions in production line shutdowns and production planning. In this paper, we introduce a method to monitor a real time process by applying a sensor to a press mold. A non-contact type sensor for measuring the flow of a sheet material and an example of an experiment using the optical sensor which is highly applicable to mass production are presented. An optical sensor was installed in a cylindrical drawing mold to test its potential application while changing the material, blank holder force, and drawing ratio. We also quantitatively determined that the flow of other sheet materials was quantified locally using a square drawing die and that the measured value was always smaller than the drawing depth due to the material elongation. Finally, we propose a field that can be used by attaching the sensor to the press mold. We hope that the consequent cost reduction will contribute to increasing global mold competitiveness.

• Journal of the Korean Institute of Gas
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• v.20 no.4
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• pp.78-84
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• 2016

In this work, finite element investigations were carried out to optimize reverse drawing process design for manufacture of high-capacity aluminum liner used in fuel cell vehicle. The tensile tests with aluminum alloy Al6061 annealed at $350^{\circ}C$ were carried out to obtain the flow stresses. In order to estimate more accurate flow stresses after necking, the flow stresses were estimated from the comparison of load vs. displacement curves which were obtained from experimental and simulation results of tensile tests. In case of finite element analyses of reverse drawing processes, it was focused on the effects of process designs such as punch and die designs, blank holding force, drawing ratio and the clearance between the punch and blank holder on the generation of wrinkle and fracture of the blank and partially heated punch. However, it was revealed that experimental results still show the fracture at the end of 2nd drawn cup, although partially heated punch is used. Nevertheless, the drawn cup can be used because the sufficient length of the drawn cup for the next flow forming process and spinning process was obtained.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.2
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• pp.62-69
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• 2016

This paper proposes to select Measure of Performance(MOP) for object attainment in the counterfire operation and deduce the reasonable combination of blue force's hitting resources satisfying MOP's optimal value and regression equation for the object achievement time. Also, in the study-methodological perspective, a series of procedures for drawing the regression equation from the real world is presented. Firstly the model was made by simplifying the weapon-system information of red force and blue force, then the time for object attainment was derived from its simulation. Simulating the model for the counterfire operation was divided into three phases-detection, decision and hitting. The probability method by applying the random numbers were used for detection, fixed constant numbers for decision and hitting. The simulation was repeatedly performed to get the minimum time for the object attainment against the fixed enemy, and it was estimated as the optimal value of simulation. From this result, the optimum combination of blue force's weapon system against the red force and finally, the regression equation were obtained by using the response surface analyzing method in MINITAB. Thereafter this equation was completely verified by using 'the 2-sample t-test.' As a result, the regression equation is suitable.