• 한국전산유체공학회:학술대회논문집
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• 2000.10a
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• pp.170-175
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• 2000

Parametric studies are performed of the factors influencing the afterbody drag. To display the effect of differing afterbody shapes, several ogive boattails with combinations of the base area and the angle of boattail end are computed using axisymmetric Navier-Stokes equations with central differencing and a DADI scheme. And Chien's $\kappa-\epsilon$ model is employed used for computations of turbulent flows around the base region. The effects of base area, boattail angle and jet on/off are illustrated on afterbody drag at transonic speed.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.11
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• pp.128-139
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• 1996

In this paper, we propose an algorithm to solve the problem of placement of rectangular blocks whose sizes and shpaes are pre-determined. The proposed method solves the placement of many retangular blocks of different sizes and shapes in a hierarchical manner, so as to minimize the chip area. The placement problem is divided into several sub-problems: hierarchical partioning, hierarchical area/shape estimation, hierarchical pattern pacement, overlap removal, and module rotation. After the circuit is recursively partitioned to build a hierarchy tree, the necessary wiring area and module shpaes are estimated using the resutls of the partitioning and the pin information before the placement is performed. The placement templaes are defined to represent the relative positions of the modules. The area and the connectivity are optimized separately at each level of hierachy using the placement templates, so the minimization of chip area and wire length can be achieved in a short execution time. Experiments are made on the MCNC building block benchmark circuits and the results are compared with those of other published methods. The proposed technique is shown to produce good figures in tems of execution time and chip area.

• Journal of Elementary Mathematics Education in Korea
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• v.22 no.4
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• pp.517-538
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• 2018

The purpose of this study is to lay the groundwork for effectively supporting mathematics learning for multi-cultural students by enhancing understanding of the cultural background regarding mathematics. In order to attain these purposes, this study compared to learning contents, deployment of contents, teaching method of the Korean and Vietnamese elementary mathematics textbooks. According to analysis, Vietnamese textbooks emphasize mathematical rigor and logic over Korean textbooks, and it integrate learning contents from various areas according to mathematical relevance. But Vietnamese textbooks do not present the connection between mathematical content, such as the combination, symmetry, and coverage of shapes. While Korean textbooks use teaching method that students find and define the concept of shapes themselves, Vietnamese textbooks present concepts of shapes and let students to learn about them. From this result, this study presented suggestions for supporting mathematics learning for multi-cultural students.

• MALSORI
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• no.56
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• pp.159-172
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• 2005

This paper analyzes the vocal tract area estimation algorithm used as a part of a speech analysis program to help deaf children correct their pronunciations by comparing their vocal tract shape with normal children's. Assuming that a vocal tract is a concatenation of cylinder tubes with a different cross section, we compute the relative vocal tract area of each tube using the reflection coefficients obtained from linear predictive coding. Then, we obtain the absolute vocal tract area by computing the height of lip opening with a formula modified for children's speech. Using the speech data for five Korean vowels (/a/, /e/, /i/, /o/, and /u/), we investigate the effects of the sampling frequency, frame size, and model order on the estimated vocal tract shape. We compare the vocal tract shapes obtained from deaf and normal children's speech.

• KIEAE Journal
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• v.13 no.4
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• pp.55-62
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• 2013

Korea Government have carried out various policies to reduce the energy consumption that cause the global warming and environmental pollution. Energy consumption of buildings in Korea has reached 24% of total energy quantities and energy consumption of apartment has been continuously increasing. It has executed the building energy efficiency rating system and energy performance assessments and certification systems have been in force to save energy consumption of buildings. Therefore, this study tried to asset the energy performance of apartment according to the shapes of unit plan, and then to evaluate the energy performance of apartment according to altering balcony area into living area in the unit plan of apartment and thus, to present the effective unit plan to reduce the energy consumption. According to the results, in case of standard unit plan, the 3Bay and 4Bay unit plans showed more effective energy consumption than the 2Bay unit plan, respectively, 5%, 6%, and in case of extended unit plan, respectively, 2%, 5%. Compared the energy efficiencies of the standard unit plan to the extended unit plan, the standard one showed more effective energy consumption than the extended one, respectively, 2% in case of the 2Bay and 4Bay unit, 5% of the 3Bay unit.

• Fashion & Textile Research Journal
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• v.22 no.1
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• pp.94-101
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• 2020

This helps plus-size consumers purchase ready-made clothes and improves fitness by analyzing the upper body shapes of abdomen-obese adult males; in addition, it creates a size system based on each size interval of obesity shapes. The criteria for the 572 male subjects surveyed were over 25 kg/㎡ of the BMI, over 90 cm of waist, and over 0.85 waist hip ratio. The results were as follows. First, the higher the age group, the higher the degree of abdominal obesity in each age group. The degree of obesity decreases age increase; however, was the risk of abdominal obesity increased. Second, Compared to standard body types, the average body size of Abdomen-obese males is significantly larger, especially in the waist area than in the chest area. Third, to propose a size system for abdominal obese adult males, 16 sections with a final 2% rate of appearance were finally adopted as suit-tops size system for abdominal obese adult males by applying a 3 cm dimension gap between each designation as specified in the KS standard. The coverage ratio for the 16 sections was 72.6% and the coverage effienciency was 4.5%. The results of this study can be used in a various clothes; in addition, the activation and segmentation of the plus-size market are also believed to be significant.

• Computers and Concrete
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• v.15 no.2
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• pp.141-166
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• 2015

In the present study, a Finite Element Model has been developed and used to study the effect of diameter to wall thickness ratio (D/t) of steel tube filled with concrete under axial loading on its behavior and load carrying capacity. The model is verified by comparing its findings with available experimental results. Influence of thickness and area of steel tube on strength, ductility, confinement and failure mode shapes has been studied. Strength enhancement factors, load factor, confinement contribution, percentage of steel and ductility index are defined and introduced for the assessment. A parametric study by varying length and thickness of tube has been carried out. Diameter of tube kept constant and equals to 140 mm while thickness has been varied between 1 mm and 6 mm. Equations were developed to find out the ultimate load and confined concrete strength of concrete. Variation of lateral confining pressure along the length of concrete cylinder was obtained and found that it varies along the length. The increase in length of tubes has a minimal effect on strength of tube but it affects the failure mode shapes. The findings indicate that optimum use of materials can be achieved by deciding the thickness of steel tube. A better ductility index can be obtained with the use of higher thickness of tube.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.89-93
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• 2008

The effect of pintle shapes and position to the thrust performance of Solid Rocket Motor was studied by experimental-aided Computational Fluid Dynamic(CFD). Among the turbulent models for RANS in Fluent, Spalart-Allmaras model was better agreement with the nozzle wall pressure distribution attained by cold-flow test than other models. When nozzle throat area was decreased, magnitude of thrust was increased. The bigger pintle size was, the more thrust of pintle tip pressure was obtained. Meanwhile the more thrust of nozzle and chamber pressure decreased. Hence, total thrust of big pintle was less than a small pintle under same throat area condition.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.11
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• pp.23-28
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• 2020

In general, lithography techniques are applied when machining single-crystal silicon in nanoscale applications; however, these techniques involve low degrees of freedom for the vertical shapes. By applying mechanical techniques to machine silicon, nanopatterns having various types of vertical shapes can be manufactured. In this study, we determined the ductile-brittle machining transition point and analyzed the- variation of the specific cutting resistance within the ductile machining region in nanoscale applications. When brittle fracture occurred during the nanoscale cutting, the depth of cut and cutting force increased and decreased rapidly, respectively. The first point of rapid increase in the depth of cut was defined as the ductile-brittle machining point. Subsequently, the shape of the machining tool was observed using a scanning electron microscope to calibrate the machining area, considering the tip blunting. The specific cutting resistance decreased continuously and converged to a certain value during the nanoscale cutting. The decrease and convergence in the value can be attributed to the decrease in the ratio of the arc length to the area of the machining tool and silicon.

• Fashion & Textile Research Journal
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• v.6 no.1
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• pp.109-113
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• 2004

The present study attempted to consider the effects of cutting lines in the knee parts of slacks on the clothing pressure and comfort. The study compared and analyzed the pressure imposed to the body in a stooping position and the consequent sensations felt by the wearer according to the slack shapes. The conclusion was drawn as follows: The pressure imposed by the slacks to the body is greater on the two points slightly upper and lower from the knee point than on the knee point itself, regardless of the slack shapes. Clothing pressure was lower in the slacks with 10 cm-wide and 14 cm-wide cutting lines in the knee parts than those with 18 cm-wide cutting lines. Subjective sensations felt in the knee parts were analyzed according to slacks shapes. As a result, it was found that slacks without cutting lines on the knee parts or with sewing lines far from the knee points were more comfortable. In slacks construction, the use of cutting lines in the knee parts can decrease pressure imposed to the knee area or improve the comfort of the slacks. When designing slacks, however, overall appearance should be considered and the weakness of cutting line that makes legs look shorter should also be complemented.