• Journal of Korea Game Society
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• v.2 no.2
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• pp.28-36
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• 2002

In general, triangular meshes have been used for modeling geometric objects such as virtual game characters. The dense meshes give us considerable advantages in representing complex, highly detailed objects, while they are more expensive for storing, transmitting and rendering the objects. Therefore, several researches have been performed for producing a high quality approximation in place of detailed objects, that is, a simplification of triangular meshes. In this paper, we propose a new measure with respect to edges and vertices, which is called an approximate mean curvature and is used as criteria to simplify an original mesh. An edge mean curvature is computed by considering its neighboring edges, and a vertex mean curvature is defined as an average of its incident edges' mean curvatures. And we apply the proposed measure to simplify the models such as a bunny, dragon and teeth. As a result, we can see that the mean curvatures can be used as good criteria for providing much better approximation of models.

• Journal of Digital Contents Society
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• v.10 no.3
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• pp.423-431
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• 2009

There are various image retrieval methods using shape, color and texture features. One of the most active area is using shape and color information. A number of shape representations have been suggested to recognize shapes even under affine transformation. There are many kinds of method for shape recognition, the well-known method is Fourier descriptors and moment invariant. The other method is CSS(Curvature Scale Space). The maxima of curvature scale space image have already been used to represent 2-D shapes in different applications. Because preexistence CSS exists several problems, in this paper we use improved CSS method for retrieval image. There are two kinds of method, One is using RGB color information feature and the other is using HSI color information feature. In this paper we used HSI color model to represent color histogram before, then use it as comparison measure. The similarity is measured by using Euclidean distance and for reduce search time and accuracy, We use DTW for measure similarity. Compare with the result of using Euclidean distance, we can find efficiency elevated.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2961-2966
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• 2007

When the pressure at the weak spot established at a certain part of a high pressure vessel or piping system exceeds a design pressure, this weak spot is burst, and the pressurized gas emitted through the weak spot will cause a compression wave system. In this connection, in the present study, an experimental study by using a conventional shock tube facility is performed to estimate the effects of the material of diaphragm, curvature radius and thickness of materials on the valve opening time in diaphragm. Pressure sensor having 500kHz in natural frequency is installed at 35mm downstream of the rupture diaphragm to measure the static pressure history of propagating and being accumulated compression wave. 4 kinds of materials are used as diaphragm that is aluminium, copper, stainless steel and zinc. The diaphragm radii of curvature R are ${\infty}$, 120mm and 60, respectively. And the depth for $90^{\circ}$ groove is 0.04mm. It is found that the smaller the tensile strength and elongation of the rupture diaphragm is, the smaller the radius of curvature of the rupture diaphragm is, and for the same conditions the thinner the thickness of the rupture diaphragm is, the shorter the valve opening time becomes. Also, the tensile strength, elongation and the radius of curvature of the rupture diaphragm for the same conditions are smaller, the maximum pressure rise caused by the coalescences of the compression wave is smaller. Finally the pressure ratio is higher, the valve opening time is shortened and gradient of pressure increment is more steepen.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.105-111
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• 2013

The present study has been carried out to reduce the heat loss from a built in refrigerator by using reverse heat loss method to discern the region with larger heat loss. To perform this purpose, an infrared thermographic camera has been used to measure the surface temperature of the refrigerator and tried to improve the heat loss near the ice dispenser. The numerical heat transfer analysis also has been accomplished to clarify the heat transfer mechanism near the ice dispenser. The possible applicable method to reduce heat loss was increasing the curvature radius at the ice dispenser corner. The curvature radius has been changed from 0mm to 40mm to see the effect of the curvature at the corner. From the present research, the optimal curvature radius for the reduction of heat loss at the ice dispenser could be 30mm.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.6 no.2
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• pp.121-132
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• 2011

Objectives : The purpose of this study is to investigate the cervical spine curvature after whiplash injury by traffic accident. Methods : The cervical lateral radiographs of 102 outpatients who visited emergency room in Kyung-Hee university hospital at Gangdong after whiplash injury by road traffic accident were reviewed to measure the cervical spine angle using C1-7, C2-7 Cobb method, Sagittal tangent method, Jochumsen method and the Ishihara index by two oriental medical doctors. For statistics, we used SPSS version 17.0 for windows. Results : Means of cervical angle are $37.63{\pm}11.34^{\circ}$, $12.92{\pm}9.13^{\circ}$, $16.19{\pm}10.62^{\circ}$, $1.78{\pm}3.37$ and $8.51{\pm}9.78$ by C1-C7 Cobb Method, C2-C7 Cobb Method, Sagittal tangent method, Jochumsen method and Ishihara index, respectively. Hypolordosis is most numeral in patients by C1-C7 Cobb Method(n=40; 39.22%), Sagittal tangent method(n=68; 66.67%). And Straight is the most by Jochumsen method(n=54; 52.94%), but Normal is the most by Ishihara index(n=53; 51.96%). And Female has smaller curvature in cervical spine than male significantly by C2-C7 Cobb method and Sagittal tangent method(P<0.05). Conclusions : Whiplash injury tends to make hypolordosis or straight. And female has more vulnerable curvature than male in whiplash injury.

• Journal of Ocean Engineering and Technology
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• v.23 no.4
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• pp.91-99
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• 2009

Many longitudinally arranged pipes in ships are subject to considerable displacement loads caused by the hull girder bending of ships and/or thermal loads in some special pipes through which fluids with highly abnormal temperatures are conveyed. As these loads may cause failure in the pipes or their supporting structures, loops have been widely adopted as a measure to prevent such failure, with the idea that they can lower the stress level in a pipe by absorbing some portion of these loads. But since such loops have some negative effects, such as causing extra manufacturing cost and occupying extra space, the number and dimensions of the loops need to be minimized. This research developed design formulas for pipe loops, modeling them as a spring element, for which the axial stiffness is calculated based on the beam theory, incorporating the effects of the curvature of loop corners and the flexibility of the straight portion of the pipe. The accuracy of the proposed design formulas was verified by comparing two results respectively obtained by the proposed formulas and MSC/NASTRAN. The paper ends with a sample application of the proposed formulas showing their efficiency.

• Physical Therapy Rehabilitation Science
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• v.11 no.1
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• pp.88-96
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• 2022

Objective: Purpose of this study was to compare muscle activity ratio of multifidus to erector spinalis according to various cueing including tactile stimulation to provide an effective strategy to provide verbal and tactile feedback during exercise to provoke multifidus muscle activation. Design: Cross-sectional study. Methods: Participants of this study included 28 healthy adults. Muscle activities of the multifidus and erector spinalis were measured while the participants performed tasks according to the three different methods of verbal cueing and three different tactile stimulation. Surface EMG was used to measure the muscular activity of the muscles during all the tasks. Results: Tactile stimulation to abdomen and lumbar vertebrae showed no significant difference in the muscle activity ratio (p>0.05). However, muscle activity ratio of the multifidus in relation to the erector spinalis was increased when subjects were given verbal instructions to make lumbar curvature with little force and to make lumbar curvature while pulling navel (p<0.05). However, it was decreased when they were provided with verbal instruction to make lumbar curvature with strong force (p<0.05). Conclusions: According to the results, proper verbal instruction was an effective tool to increase the muscular activity of multifidus. This study aimed to find and provide the most appropriate verbal cueing while doing exercises to activate multifidus.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.2
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• pp.127-133
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• 2012

Perpose: The aim of this study is to investigate the measuring method in radius of eyeglasses lens curvature by using keratometer in noncontact method. Methods: A trial lens for vision test in diopter range from -9.00 D to -11.50 D were attached in front part of keratometer, after that we set eyeglasses lens at the place where eyeglasses lens is apart about 25 cm from front position of keratometer. We measured the radius of curvature from observation of clear mire image while the position of eyeglasses lens is changed in a small quantity. After that, we made some formulas for compensation of radius of curvature by using spherometer. Results: The radius of curvature was successfully measured by keratometer with trial lens in front part of it. The measured radius of curvature was changed to compensation value using spherometer data, and the 5 kind of linear equation to make compensation value was made. Any kind of lenses measured by using keratometer that trial lens was attached in front part of it, after that it was confirmed that the result of calculation from line equation is exact in error ratio below 3.5%. Conclusions: It was confirmed that radius of eyeglasses lens curvature can be measured by using keratometer by noncontact method, and the accuracy is higher than "lens measure".

• Korean Journal of Applied Biomechanics
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• v.30 no.1
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• pp.93-101
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• 2020

Objective: The purpose of this study was to differences of foot plantar pressure balance and lung capacity according to cervical posture in adults. Method: The subjects consisted of 33 adults in their 20s and 50s who use M centers in B-gu and H-gu, B-City, and they measured foot plantar pressure balance and lung capacity according to cervical posture (cervical normal curvature posture, cervical flexural posture) in adults. Results: In this study, the difference of foot plantar pressure balance according to cervical posture were analyzed. In the difference between left and right foot pressure balance. It was 1.50% increased in the cervical flexural posture than in the cervical normal curvature posture, and a statistically significant difference was observed. In the difference between the anterior and posterior foot pressure balance. It was 4.28% increased in the cervical flexural posture than in the cervical normal curvature posture, and a statistically significant difference was observed. The difference of lung capacity according to cervical posture were analyzed. In the PEF, It was 58.63 l/min decreased in the cervical flexural posture than in the cervical normal curvature posture, and a statistically significant difference was observed. In the FEV1, It was 0.15 ℓ decreased in the cervical flexural posture than in the cervical normal curvature posture, and a statistically significant difference was observed. Conclusion: The results of this study suggest that had a positive effect on differences of foot plantar pressure balance and lung capacity at cervical normal curvature posture in adults. In future research, itis believed that research on the elderly who have collapsed the normal curvature posture due to aging, as well as teenagers whose normal curvature posture due to the use of smartphones, will contribute to the balance of foot pressure and improvement of the right cervical habits. In future studies, it is also believed that it will be necessary to measure lung capacity after performing exercise according to the cervical posture, thereby providing sufficient oxygen during exercise to enhance the persistence and efficiency of the movement.

• Journal of the Korean Society of Clothing and Textiles
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• v.14 no.3 s.35
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• pp.183-195
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• 1990

The author has studied the effect of clothes design to mask the dorsal curvature that is one of the commonest changes in elderly women. Body measurements including the body type and the status of dorsal curvature were perfor-med on 153 women of over 60 years of age, and then a body form to fit to the mean measure-ments was made to evaluate the effects of various designs to it. With 31 pattern designs modified by changing in their slash lines and gathers using darts, the diminishing effect of the rounded back were evaluated by means of sensory test. The results of this study can be summarized as follows: I . Results from the body measurements 1) The mean body type in elderly women was that of obesity. 2) With the advancement of age, the angle to indicate the degree of dorsal curvature as well as the angle to indicate the posture are increased. II . Concerning to the clothes design to diminish the shape of dorsal curvature 1) Among the designs by the position of darts, the basic pattern (Fig. 5-1-(1)) showed the best effect to mask the shape of dorsal curvature. 2) Out of the applied designs of princess lines, that in which the slash line is pointing toward the shoulder point (Fig. 5-2-(1)) seemed to be most effective. 3) What has angled princess line (Fig. 5-3-(1)) had the most diminishing effect among the waist darts and armhole princess lines. 4) Among the V-shaped designs, the slashed at the shoulder point (Fig. 5-4-(1)) had the best effect to lessen the shape of the dorsal cuuature. 5) Wider angle yoke had better effect to the narrow angle one among the designs with straight yoke, and that with downward direction (Fig. 5-5-(1)) showed the best effect. 6) Between straight wide angle yoke and curved yoke, that of curved one with downward direction (Fig. 5-6-(1)) had better effect as far as the masking effect of dorsal curvature is concerned. 7) Gathers around the neck showed better effect to those around the shoulder, and the more amount of gathers (Fig. 5-7-(1)), there was better effect. 8) The design with midline gathers at the level of horizontal slash line of armhole (Fig. 5-8-(1)) showed better effect to that with seperated gathers. 9) In case of design with gathers at the horizontal line of armhole, it showed the better effect with less amount of gathers in midline ones, but with more amount in the side ones. 10) Considering all 7 different designs with better effect in covering the shape of dorsal curvature, it was evident that the design with gathers was far better than the design with application of slash lines.