• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.12
• /
• pp.174-181
• /
• 1999

This paper describes the effect of the stylus tip size on the shape error in surface topography measurement. To analyze the distortional effect of an actual surface geometry origination from the finite stylus size, the surface is modeled as a sinusoid and the stylus tip as a circle. The magnitude of this distortion is defined as the ration of standard deviation, and this is expressed as an analytic function of the stylus tip radius and the geometrical parameter of a sinusoid. In this paper, the spectrum analysis of the profile is applied to investigate the distortional effect due to the mechanical filtering of the stylus in the frequency domain. and, the cumulative power spectrum is proposed to assess the shape error of measured data according to the various stylus tip sizes. From these results, a new method to select proper stylus tip radius is proposed.

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.1237-1242
• /
• 2007

For the various RP processes and machines, quantitative comparisons were carried out, which include the variations of roughness according to inclined angle of surface, tensile strength and heat-resistance, shape accuracy affected by curl distortion, manufacturability of submilli-scale structure, and manufacturing speed. It was observed that steeper surface results in smoother roughness except Eden500V of Objet. Specimen made by LOM process showed the best heat-resistance, but that of SL process had heat-resistance only up to $60^{\circ}C$. Generally, tensile strength in the building direction was shown to be smaller than in the scanning direction, but SL process showed the opposite results. RM6000II of CMET was superior in the manufacturing small-scale structure below 0.2mm, and Z510 of Zcorp. and ViperPRO of 3D systems were great in manufacturing speed.

• The KSFM Journal of Fluid Machinery
• /
• v.9 no.6 s.39
• /
• pp.9-16
• /
• 2006

Performance characteristics of an axial flow fan having distorted inlet flow have been investigated using numerical analysis as well as experiment. Two kinds of hub-cap, rounded and right-angled front shape, are tested to investigate the effect of inlet flow distortion on the fan performance. Numerical solutions are validated in comparison with experimental data measured by a five-hole probe downstream of the fan rotor. It is found from the numerical results that non-uniform axial inlet velocity profile near the hub results in the change of inlet flow angle. Large recirculation flow upstream the fan rotor for the right-angled hub-cap induces a negative incidence, thus invokes separated flow on the blade surfaces and deteriorates the performance of fan rotor.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2003.10a
• /
• pp.420-425
• /
• 2003

Generally, reverse engineering means getting CAD data from unidentified shape using vision or 3D laser scanner system. In this paper, we studied unidentified model by machine vision based reverse engineering system to get information about in-processing model. Recently, vision technology is widely used in current factories, because it could inspect the in-process object easily, quickly, accurately. The following tasks were mainly investigated and implemented. We obtained more precise data by corning camera's distortion, compensating slit-beam error and revising acquired image. Much more, we made similar curves or surface with B-spline approximation for precision. Until now, there have been many case study of shape recognition. But it was uncompatible to apply to the field, because it had taken too many processing time and has frequent recognition failure. This paper propose recognition algorithm that prevent such errors and give applications to the field.

• Journal of the Korean Home Economics Association
• /
• v.50 no.1
• /
• pp.29-39
• /
• 2012

The purpose of this research is to suggest a scarf design which reflects the traditional culture native to Korea by making use of the combined pattern of jokgakbo patchwork and ddeoksal(rice cake). For research methodology, the computer design programs of Adobe Illustrator CS3 and Adobe Photoshop CS3 were used along with the related literature. For the combined sets of motif pattern, the following were consider: first, a combination of jogakbo in square shape and chrysanthemum in a rice cake mold; second, a combination of radius jogakbo and geometrical pattern; third, a combination of vertical and horizontal forms of jogakbo and rice cake pattern; fourth, a combination of yeouijumunbo and butterfly pattern in rice cake mold. For the scarf design with these applications, technical skills such as repeat, rotation, symmetry, free setup, and distortion were used for the combination motif. In terms of the shape of the design, there are two, square and lengthwise tetragons.

• The Journal of the Korean dental association
• /
• v.53 no.7
• /
• pp.457-467
• /
• 2015

Patients with cleft lip and palate require interdisciplinary treatment to achieve successful rehabilitation. However, there are special difficulties in orthodontic treatment of adult cleft lip and palate patients: 1. Lack of Tissue, Bone, and Soft tissue; 2. Heavy Scar Tissue, Vestibule, and Palate; 3. Severe Anteroposterior discrepancy and Impaired Maxilla; 4. Distortion of Alveolar Ridge; 5. Abnormal Eruption Path and Malalignment of Tooth. Solving these problems, orthodontist should have differential diagnosis on extent of cleft site and residual deformities of adult cleft lip and palate patient. The tooth missing area in cleft site was commonly treated with a removable or fixed prosthesis, but this method is not stable to retain maxillary arch shape. To establish the more stable arch shape in cleft lip and palate, endosseous implants in the alveolar clefts with bone graft is helpful for management of adult cleft lip and palate patient.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.6 no.3
• /
• pp.123-138
• /
• 2004

The objective of this study is to review the expressive effect of fashion illustrations and to enlarge its expressive range by analysing the correlations between fashion illustrations and surrealistic expressive characteristics. The results are as follows. The surrealistic expressive methods of fashion illustration such as depaysement and automatism have been used by many foreign and domestic fashion illustrators. I think that these methods reinforce the subjective aspect of expressive effects and enlarge the transmitting function of fashion message. The elements of expression are divided into color, texture, shape/form and space. Subjective colors rather than natural colors are used for the surrealistic expressive effect of color in fashion illustrations, and illusion of space is expressed by the change of brightness. The surrealistic expressive effect in fashion illustrations distorted the experience of factual texture and disturbed the visual texture. The use of tactile texture presented strange effects perspectively. The objects of shape in fashion illustrations were mainly human body. The form of human body presents reconstituted and reinterpreted figure by transformation or distortion according to the intention of the artist rather than realistic and physical form. In fashion illustration, the transformation of the human body itself whose body parts get separated, superposition of exterior material and human body, and the distortion of human body by the change are done. Space is where background and shapes are inter-penetrated because they are ambiguous and untransparent, and where all are in disorder and unbalance. The method of projection uses distance perspective, multiple perspective and amplified perspective representation, and forms a psychological space feeling. And I think the use of surrealistic expressive methods are very useful for the subjective sensitiveness and the transmission of a fashion message, and presents a possibility to develop a new expressive method.

• Journal of Biosystems Engineering
• /
• v.42 no.1
• /
• pp.1-11
• /
• 2017

Purpose: Methods: Three-dimensional CFD modeling was conducted to analyze the flow structure and discharge flow rate corresponding to the variation in the geometry of the flow channel in a microtube. Additionally, experiments were carried out, and the discharge flow rate was measured at various inlet pressures and inclination angles of the microtube. Results: The quantitative data of velocity distribution and discharge flow rate were obtained. As the width and length of the microtip increased, the discharge flow rate decreased significantly because of the increase in the loss of pressure along the microtube. As the depth of the microtip increased, the flow rate also increased because of the reduction in the flow resistance. However, in this analysis, the variation in the angle of the microtip did not influence the flow rate. From the experimental results, it was observed that the flow rate increased linearly with the increase in the inlet pressure, and the effects of the inclination angle were not clearly observed in those test cases. The values of the flow rate obtained from the experiments were significantly lower than that obtained from the CFD analysis. This is because of the distortion of the shape of the flow path inside the microtube during the fabrication process. The distortion of the flow path might decrease the flow cross-sectional area, and it would increase the flow resistance inside the microtube. The variation in the flow rate corresponding to the variation in the inlet pressure showed similar trends. Conclusions: Therefore, the results of the numerical analysis obtained from this study can be efficiently utilized for optimizing the shape of the microtip inside a microtube.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.20 no.4
• /
• pp.117-130
• /
• 2018

As women wear shoes for a long time due to aesthetic elements and working environment, many women experience discomfort and deformation in their feet due to their shoes and the production of comfortable shoes is becoming an important issue. The purpose of this study is to investigate the factors affecting the grip of shoes by foot type, shoe design, and wearing attitude of shoes. Through this, we suggest solutions for foot discomfort due to wearing shoes and help to prevent foot related diseases. The study results are as follows; first, a wide foot, square-type, and high or low arch (hollow foot or flat foot) among foot shapes influenced the fatigue and pain of feet, and big feet over 250mm-long, wide feet, square-type feet, and high-arch feet (hollow foot) had an influence on distortion and side effects. Second, among the characteristics of wearing shoes influencing foot discomfort, the higher the shoe heels were, the narrower the surface covering the feet was (pumps and mule), and the shoes with high front heels and narrow back heel area, the shoe wearer had a higher possibility of experiencing fatigue and pain and even had not only fatigue and pain but also side effects when she wore pointed shoes. Third, a shoe wearer experiences fatigue and pain if she wears shoes for a shorter period of time, stay stood while wearing shoes for a short time, and wears shoes that are bigger or smaller than the actual shoe size. Fourth, fatigue and pain experiencers and distortion and side effects experiencers all responded that they change into other shoes to deal with foot discomfort and that they directly massage their feet.

• Journal of Power Electronics
• /
• v.13 no.4
• /
• pp.546-551
• /
• 2013

This paper deals with the optimum design of the stator and rotor shape of the interior permanent magnet synchronous motors (IPMSM) that are used in applications for automobiles. IPMSMs have the following advantages: high power, high torque, high efficiency, etc. However, cogging torque which causes noise and vibrations is generated at the same time. The optimum design of shape of a IPMSM was carried out with the aim of reducing cogging torque. Six variables which affect to the performance of a IPMSM are chosen. The main effect variables were determined and applied to the response surface methodology (RSM). When compared to the initial model using the finite elements method (FEM), the optimum model highly reduces the cogging torque and improves the total harmonics distortion (THD) of the back-electro motive force (EMF). A prototype of the designed model was manufactured and experimented on to verify the feasibility of the IPMSM.