• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.328-331
• /
• 2001

Shape changes of a workpiece in an Eulerian Finite Element analysis for the steady state. three-roll-stand shape rolling are modelled. Although an Eulerian analysis has many advantages for the steady state rolling problems, it necessitates an assumption about the unknown shape of the control volume. In almost all cases. the assumed control volume does not match the final shape and the control volume should be updated. This update can be accomplished by performing a free surface correction. The final shape of a material point, which has a spherical shape at the inlet, can be also predicted by integrating a deformation gradient along a stream line. Analyses of three-roll-stand shape rolling is in detail examined.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.417-422
• /
• 2002

The main purpose of this paper is to determine the dynamic optimal shapes of tapered column with constant volume. The linear, parabolic and sinusoidal tapers with the regular polygon cross-section are considered, whose material volume and span length are always held constant. The ordinary differential equation including the effect of axial load is applied to calculate the natural frequencies. The Runge-Kutta method and Regula-Falsi methods are used to integrate the differential equation and compute the frequencies, respectively. Then the dynamic optimal shape whose lowest natural frequency is highest is determined by reading the critical value of the frequency versus section ratio curve plotted by the frequency data. In the numerical examples, the tapered columns are analysed and the numerical result of this study are shown in table and figures.

• Korean Journal of Geomatics
• /
• v.2 no.1
• /
• pp.25-29
• /
• 2002

The calculation of earthwork plays a major role in plan or design of many civil engineering projects, and thus it has become very important to improve the accuracy of earthwork calculation. In this paper, we propose an algorithm for finding a cubic spline surface with the free boundary conditions, which interpolates the given three dimensional data, by using B-spline and an accurate method to estimate pit-excavation volume. The proposed method should be of interest to surveyors especially concerned with accuracy of volume computations. We present some computational results showing that our proposed method provides good accuracy.

• The Korean Journal of Community Living Science
• /
• v.26 no.3
• /
• pp.447-456
• /
• 2015

To develop functional bread and improve the quality of gluten-free bread, this study investigates the quality characteristics of gluten-free rice bread made from soft-type rice (Bodeurami) flour mixed with black rice at different levels (0%, 10%, 20%, 30%, and 40%, w/w). An increase in the mix level of black-rice flour increased the weight of rice bread but reduced its volume, baking loss, volume expansion, and specific volume. The results for Hunter's color value and texture measurements indicate that an increase in the content of black-rice flour reduced the L-value, the b-value, hardness, gumminess, and chewiness but increased the a-value, adhesiveness, and springiness. According to the sensory analysis, rice bread formulated with a mixture of soft-type rice flour (80%) and black-rice flour (20%) showed the highest scores in color, taste, texture, and overall preferences. With respect to flavor and appearance, bread samples with 20% and 30% black-rice flour were preferred to those with 0%, 10%, and 40% black-rice flour. These results suggest that gluten-free rice bread mixed with wet-milling rice flour and black-rice flour can be used to develop functional and gluten-free bread.

• Journal of the Society of Naval Architects of Korea
• /
• v.42 no.2 s.140
• /
• pp.88-97
• /
• 2005

A new numerical scheme solving two-phase flow, the Hybrid VOF method for improved free surface capturing has been developed by combining a volume capturing VOF method with the Level-Set reinitialization procedure. For validation, the proposed method is applied to 3-D bubble rising problem, dam breaking and the free surface flow around a commercial container ship. The calculated results by using the Hybrid VOF method with the two previously applied VOF formulations are compared with available numerical and experimental data. It is found that the new method provides more reasonable results than the two previous ones.

• Structural Engineering and Mechanics
• /
• v.82 no.2
• /
• pp.151-161
• /
• 2022

In this study, the effect of porosity distribution pattern on the free vibration analysis of porous FG plates with various boundary conditions is studied. The material properties of the plate and the porosities within the plate are considered to vary continuously through the thickness direction according to the volume fraction of constituents defined by the modified rule of the mixture, this includes porosity volume fraction with four different types of porosity distribution over the cross-section. The governing partial differential equation of motion for the free vibration analysis is obtained using hyperbolic shear deformation theory. An analytical solution is presented for the governing PDEs for various boundary conditions. Results of the presented solution are compared and validated by the available results in the literature. Moreover, the effects of material and porosity distribution and geometrical parameters on vibrational properties are investigated.

• Journal of the Korean Data and Information Science Society
• /
• v.17 no.2
• /
• pp.529-536
• /
• 2006

Investigators use either Euclidean distance or volume of a simplex defined composed of data points as agreement index to measure chance-corrected agreement among observers for multivariate interval data. The agreement coefficient proposed by Um(2004) is based on a volume of a simplex and does not depend on the variables' measuring units. We consider a comparison of Um(2004)'s agreement coefficient with others based on two unit-free distance measures, Pearson distance and Mahalanobis distance. Comparison among them is made using hypothetical data set.

• Investigative Magnetic Resonance Imaging
• /
• v.13 no.1
• /
• pp.63-73
• /
• 2009

Purpose : To investigate the effects of various intracranial volume (ICV) measurement methods on the sensitivity of hippocampal volumetry and modulated voxel-based morphometry (mVBM) in female patients with major depressive disorder (MDD). Materials and Methods : T1 magnetic resonance imaging (MRI) data for 41 female subjects (21 MDD patients, 20 normal subjects) were analyzed. Hippocampal volumes were measured manually, and ICV was measured manually and automatically using the FreeSurfer package. Gray and white matter volumes were measured separately. Results : Manual ICV normalization provided the greatest sensitivity in hippocampal volumetry and mVBM, followed by FreeSurfer ICV, GWMV, and GMV. Manual and FreeSurfer ICVs were similar in normal subjects (p = 0.696), but distinct in MDD patients (p = 0.000002). Manual ICV-corrected total gray matter volume (p = 0.0015) and Manual ICV-corrected bilateral hippocampal volumes (right, p = 0.014; left, p = 0.004) were decreased significantly in MDD patients, but the differences of hippocampal volumes corrected by FreeSurfer ICV, GWMV, or GMV were not significant between two groups (p > 0.05). Only manual ICV-corrected mVBM analysis was significant after correction for multiple comparisons. Conclusion : The method of ICV measurement greatly affects the sensitivity of hippocampal volumetry and mVBM. Manual ICV normalization showed the ability to detect differences between women with and without MDD for both methods.

• The Journal of Korean Society for Radiation Therapy
• /
• v.25 no.2
• /
• pp.187-192
• /
• 2013

Purpose: We investigate the results of changed heart volume and heart dose in the left breast cancer patients while considering the movements of respiration. Materials and Methods: During the months of March and May in 2012, we designated the 10 patients who had tangential irradiation with left breast cancer in the department of radiation Oncology. With acquired images of free breathing pattern through 3D and 4D CT, we had planed enough treatment filed for covered up the whole left breast. It compares the results of the exposed dose and the volume of heart by DVH (Dose Volume histogram). Although total dose was 50.4 Gy (1.8 Gy/28 fraction), reirradiated 9 Gy (1.8 Gy/5 Fraction) with PTV (Planning Target Volume) if necessary. Results: It compares the results of heart volume and heart dose with the free breathing in 3D CT and 4D CT. It represents the maximum difference volume of heart is 40.5%. In addition, it indicated the difference volume of maximum and minimum, average are 8.8% and 27.9%, 37.4% in total absorbed dose of heart. Conclusion: In case of tangential irradiation (opposite beam) in left breast cancer patients, it is necessary to consider the changed heart volume by the respiration of patient and the heartbeat of patient.

• Archives of Plastic Surgery
• /
• v.37 no.5
• /
• pp.607-612
• /
• 2010

Purpose: Maxillectomy for malignant tumor resection often leads to functional and aesthetic sequalae. Reconstruction following maxillectomy has been a challenging problem in the field of head and neck cancer surgery. In this article, we described three dimensional midface reconstructions using free flaps and their functional and aesthetic outcomes. Methods: We reconstructed 35 cases of maxillectomy defects using 9 radial forearm free flaps, 7 lattisimus dorsi musculocutaneous free flaps, 6 rectus abdominis musculocutaneous free flaps, 4 fibular osteocutaneous free flaps, and 9 anterolateral thigh free flaps, respectively. We classified post-maxillectomy defects by Brown's classification. 1 Articulation clarity was measured with picture consonant articulation test. Swallowing function was evaluated with the University of Washington quality-of-life Head and Neck questionnaire by 4 steps.2 Aesthetic outcomes were checked to compare preoperative with postoperative full face photographs by 5 medical doctors who did not involve in our operation. Results: The average articulation clarity was 92.4% (100-41.9%). 27 (81.9%) patients were able to eat an unrestricted diet. Aesthetic results were considered excellent in 18 patients (51.4%). Functional results were best in the group reconstructed with fibular osteocutaneous free flap. Considering the range of wide excision, aesthetic results is best in the group reconstructed with anterolateral thigh free flap. Conclusion: The free flap is a useful technique for the reconstruction of the midface leading to good results, both functionally and aesthetically. Especially, because osteocutaneous flap such as fibular osteocutaneous free flap offered bone source for osteointegrated implant, It produces the best functional results. And perforator flap like as anterolateral thigh free flap reliably provides the best aesthetic results, because it provides sufficient volume and has no postoperative volume diminution.