• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.1
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• pp.49-54
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• 1995

Three types of floating-type automatic inlet were developed for the purpose of reduc- ing farmer's working hours required for water management and saving irrigation water. The point of automation is to use a float within the inlet which is floated and sinked by the ponding depth of paddy field, Thus opens and closes the control gate of irrigation. Suitability of each inlet may depend on production cost, applicability to paddy field condi- tions, and feasibility to farmers, etc. The first model was composed of three parts : chamber for irrigation control gate, chamber for float controlled by ponding depth, and connection bar between the two parts. It was designed to open and close the control gate gradually as the ponding depth drops and rises to a certain level. The second model was designed to improve the weak point of the first model which is the imperfect-closing of gate when it approaches to the end of ir- rigation. A switch-spring was equipped above the connection bar for perfect opening and closing of gate when the ponding depth reaches to a certain level. The third model was designed by combining the two chambers, that is, cut in halves the inlet volume of the above two models. Magnets were equipped above the float for perfect opening and closing gate. The functional experiment for three developed inlets was successfully carried out and the rating curves were derived.

• The Journal of the Korea Contents Association
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• v.19 no.2
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• pp.684-694
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• 2019

This study deals with the university students who experienced closing department in the restructuring process of university. The purpose of this study is to examine what kind of experience university students have experienced and to understand the essence of the experience in depth. For this purpose, the subjects of the study conducted in - depth interviews with 6 students who expressed their intention to participate in the study. Results of the study were analyzed through the phenomenological study procedure of Giorgi, a qualitative research method. As a result, eight essential themes and sixteen sub themes were derived. The eight essential themes are 'an event of a psychological difficulty', 'deepening a negative emotions', 'anxiety about the future', 'desperation', 'discrimination', 'efforts to overcome difficulties', 'regret and sorriness' and 'acceptance'. Participants in this study suggested ways to reduce psychological difficulties for students who were in closing department condition. Participants said that they needed to provide accurate information about closing department, provide students with the right to know, prepare alternative plans, and emotional cares. The implications of these results are discussed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.3
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• pp.26-35
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• 1997

In this study, the drawing characteristics of circular drawbead are examined with the plane strain elastic-plastic FE Method. Both the clamping load and the drawing load investigated by varying the process variables such as drawbead radius, closing depth and friction condition. The effective strain induced by the draw bead is also investigated. In order to verify the results, the computed results are compared with the existing experimental results. It has been found that both the clamping load and drawing loads are related with the geometry of the bead rather than the lubrication conditions.

• The korean journal of orthodontics
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• v.50 no.2
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• pp.120-128
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• 2020

Objective: The aims of the present study were to evaluate the changes in the maximum lip-closing force (MLF) after orthodontic treatment with or without premolar extractions and verify the correlation of these changes with dentoskeletal changes. Methods: In total, 17 women who underwent nonextraction orthodontic treatment and 15 women who underwent orthodontic treatment with extraction of all four first premolars were included in this retrospective study. For all patients, lateral cephalograms and dental models were measured before (T0) and after (T1) treatment. In addition, MLF was measured at both time points using the Lip De Cum LDC-110R^® device. Statistical analyses were performed to evaluate changes in clinical variables and MLF and their correlations. Results: Both groups showed similar skeletal patterns, although the extraction group showed greater proclination of the maxillary and mandibular incisors and lip protrusion compared to the nonextraction group at T0. MLF at T0 was comparable between the two groups. The reduction in the arch width and depth and incisor retroclination from T0 to T1 were more pronounced in the extraction group than in the nonextraction group. MLF in the extraction group significantly increased during the treatment period, and this increase was significantly greater than that in the nonextraction group. The increase in MLF was found to be correlated with the increase in the interincisal angle and decrease in the intermolar width, arch depth, and incisor-mandibular plane angle. Conclusions: This study suggests that MLF increases to a greater extent during extraction orthodontic treatment than during nonextraction orthodontic treatment.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.42-47
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• 1997

In this study, the drawing characteristics of circular drawbead are examined with the plane strain elastic-plastic FE Method by varying the process variables such as friction coefficient, drawbead radius, and closing depth. Numerical analysis are carried out by 2-D elastic-plastic F.E.M. The results are compared with the existing experimental results about the drawing force, the die clamping force, and the strain distribution of upper and lower sheet faces

• Journal of Industrial Technology
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• v.21 no.A
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• pp.17-26
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• 2001

The fatigue strength of SM55C has significantly decreased by 83% compared with atmosphere where distilled exists due to strong erosive action of acid fog. The reason is inferred in a way that strong acid erosive material such as acid fog act and give rise to multi-site crack on the surface. Several fatigue clacks occurred under the acid fog repeat the process of division and unification on the surface and form a long non-propagating crack throughout the circumference of experimented steel. However, in the depth, many parts do not show much trace of unification, and the depth is not as big as the one of normal crack shape. 10% of $CaCl_2$ causes strong erosive reaction to material. Then eventually make the life of fatigue shooter. On the other hand, 20% of $CaCl_2$ beings about oxidized material organic crack closing due to weak erosive reaction.

• Journal of Welding and Joining
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• v.31 no.4
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• pp.23-27
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• 2013

Laser heat source was used for automotive interior and exterior parts to reduce weights. Typically, 900's nm wavelength of laser has been widely used for polymer joining, however, the transmittance of the laser beam thorough clear polymers such as PMMA or PC has been an issue to overcome. To solve this issue, 1,940nm laser was applied on the clear polymer for the better absorption and 900nm laser beam was used for main laser for the joining. Conventional Gaussian or Elliptical heat source approximation has limitation in polymer which had deeper skin depth where major laser beam absorbs. To accurately simulate the physical laser beam absorption and joining optical properties were experimentally measured for the computer FEM simulation. The simulation results showed close correlation between theoretical and experimental results. The developed laser process is expected to increase productivity and gap closing which can cause failure of joining in laser material processing.

• Journal of the HCI Society of Korea
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• v.2 no.2
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• pp.1-9
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• 2007

In this paper, we propose a reconstruction technique of the lost hair region for 3D human actor modeling. An active depth sensor system can simultaneously capture both color and geometry information of any objects in real-time. However, it cannot acquire some regions whose surfaces are shiny and dark. Therefore, to get a natural 3D human model, the lost region in depth image should be recovered, especially human hair region. The recovery is performed using both color and depth images. We find out the hair region using color image first. After the boundary of hair region is estimated, the inside of hair region is estimated using an interpolation technique and closing operation. A 3D mesh model is generated after performing a series of operations including adaptive sampling, triangulation, mesh smoothing, and texture mapping. The proposed method can generate recovered 3D mesh stream automatically. The final 3D human model allows the user view interaction or haptic interaction in realistic broadcasting system.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.6
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• pp.1490-1500
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• 1995

Compression molding of SMC (Sheet Molding Compound) in a thin plaque with substructures like a rib is involved with the formation of surface defect along the centerline over the rib area called by sink mark depending on process parameters. The surface quality of the external panels in automotive manufacturing is so critical that this kind of defect should be eliminated during manufacturing stages. The effect of process parameters on sink mark formation and the distribution of chopped fiberglasses in the compression molded thin plaque with a rib was experimentally investigated in the present study. In order to estimate the effect of the molding parameters such as molding temperature, mold closing speed, depth of the rib, corner radius of the rib, and final molded part thickness of flat portion on the depth of sink mark and the distribution of fiberglasses in the molded SMC part with the rib under the present experimental conditions, the molding parameters used in experiments were non-dimensionalized equation for predicting the depth of sink mark was determined through dimensional analysis based on the experimental data. The orientation and distribution of fiberglasses and fillers which directly affect the formation and depth of sink mark were investigated by taking the photographs of the cross-sectional area of the molded specimen using scanning electron microscope. The experimental results proposed from this investigation are useful in understanding the formation of sink mark and predicting the depth of sink mark in compression molding of SMC with substructures.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.622-628
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• 2003

The purpose of this study is to evaluate the effect of local wall thinning on the collapse of elbow subjected to internal pressure and bending moment. Thus, the nonlinear 3D finite element analyses were performed to obtained collapse moment of elbow containing various wall thinning defects under two loading; modes (closing and opening modes) and defect locations (intrados and extrados). From the results of analyses, the influence of wall thinning defect on the global moment-rotation behavior of elbow was discussed, and the dependance of collapse moment of elbow on wall thinning depth, length, and circumferential angle was investigated under different loading mode and defect location.