• 한국지능시스템학회논문지
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• 제15권1호
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• pp.48-52
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• 2005

본 논문에서는 음성의 스펙트럼 형태는 유지하면서 음성을 기계적인 음성으로 변환시키기는 실시간 음성 변환 방법을 제안하였다. 이러한 목적을 위하여 LPC 분석 및 합성 방법을 사용하여 변환된 음성의 스펙트럼은 유지하였고 합성된 음성의 피치는 자유롭게 변경되도록 하였다. 제안된 방법에서는 변환된 음성이 보다 자연스럽게 들리게 하기 위하여 여기 신호 발생기에 이득 정합 방법을 적용하였다. 제안된 방법의 성능을 평가하기 위하여 음성 변환 실험을 수행하였다. 실험 결과에서 원 음성 신호는 원 화자의 신원을 알기가 어려운 기계적인 음성 신호로 바뀌는 것을 알 수 있었고 피치의 심한 변화에도 변환된 음성의 의미는 정확히 전달될 수 있었다. 제안된 시스템은 시스템의 실시간으로 구현될 수 있는지 확인하기 위하여 TI TMS320C6711DSK 보드를 사용하여 구현되었다.

• 건축역사연구
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• 제25권4호
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• pp.31-44
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• 2016

Geum'yeok-dang house in Andong was originally constructed in 1558. The original floor plan of the upper base featured a 90-degree tilted '日' shape, and had inner court(內庭) on each side of 'Jungdang(中堂, center hall)' building that was placed on the south-north axis. When designing the building, the Neo-Confucian client of Geum'yeok-dang applied his understanding of how Ga'rye("家禮") defined the structure of ritual space. Consequently, 'Daecheong(大廳)', the place where guests were greeted and ancestral rites and coming of age ceremonies for male were held, was built in a protruding fashion. 'Jungdang'[otherwise known as 'Jeongchim(正寢)'], where coming of age ceremonies for females were held, the master of the house faced death, and memorials for close ancestors were held, was placed at the center of the residence on the south-north axis. The Geum'yeok-dang today was greatly renovated in the early and mid 18th century, due to the spread of 'Ondol' heating system. As the Ondol heating system became popular, the pre-existing drawbacks and the inconvenience of the house stood out clearly. As a result, the house was renovated into today's structure consisting of '口' shape 'Anchae' and 'Daecheongchae' in separate building.

• 한국과학교육학회지
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• 제25권1호
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• pp.41-56
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• 2005

Assessing students' knowledge can be a challenging endeavor, as researchers attempt to capture the full complexity and potential development of children's ideas. In this study, the Dynamic Science Assessment (DSA) method (Magnusson, Templin, and Boyle, 1997) was employed to investigate 9-12 year old students' understandings of light, while engaging in multiple tasks with a flashlight with various reflectors and mirrors. The results showed that DSA was effective in providing an opportunity to establish a Zone of Proximal Development, in addition to diagnosing a student's prior understanding. Throughout the interview, a student showed a conceptual model of light as being a solid single entity whose shape can be determined by the shape of the casing of a flashlight. However, as DSA provided phenomena that could not be explained by his unitary model, the student began to re-examine his original conceptual model, and attempted to revise it. This study addressed how Dynamic Science Assessment can help us better understand, not only students' current state of understanding, but also a potential development of understanding in their ZPD. In that sense, this study argues that we should pay more attention to the instructive role of classroom assessment that can promote and support further development of students' deeper understandings.

• 소성∙가공
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• 제1권1호
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• pp.66-74
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• 1992

According to the variation of hydrostatic pressure on the central axis of deformable material, the V-shaped central bursting defect may be created in extrusion or drawing processes. The process factors which affect the generation of defects are semi-angle of die, reduction ratio of cross-sectional area, friction factor, material properties and so on. The combination of these factors can determine the possibility of defect creation and the shape of various round holes which have been created inside already. By the rigid plastic finite element method, this paper describes the observations of change in shape of round holes with process conditions such as semi-angle of die, reduction ratio of cross-sectional area and friction factor at the non-steady state of axisymmetrical extrusion process when the round hole is already existed inside the original billet. Also, the effects of process factors are investigated to prevent the possible defects.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.572-577
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• 2004

This paper presents numerical study on the performance improvement of the sirocco fan in a range hood. The performance of sirocco fan means a higher flowrate, a higher static pressure and a lower required motor power in a fixed geometry constraint. Various impeller geometric parameters, such as blade profile, blade diameter, blade thickness profile and blade exit angle, were investigated by numerically and the results were compared with each other to know the effects on the performance. In this approach, the volute geometry were fixed with the original shape. The numerical results show that the blade profile with airfoil shape and small exit blade thickness increases the performance. The blade exit angle shows optimum angle within a varied range. The efficiency of the optimized exit angle was about $10\%$ higher than the base blade exit angle and the static pressure was about $28\%$ higher at the flow coefficient 0.22.

• International Journal of Railway
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• 제4권4호
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• pp.109-115
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• 2011

An analysis and design method for reducing aerodynamic noise in high-speed trains based on biomimetics of noiseless flight of owl is proposed. Five factors related to the morphology of the flight feather have been selected, and the candidate optimal shape of the flight feather is determined. The turbulent flow field analysis demonstrates that the optimal shape leads to diminished vortex formation by causing separation of the flow as well as allowing the fluid to climb up along the surface of the flight feather. To determine the effect of scaling of the owl's flight feather on the noise reduction, a two-fold and a four-fold scaled up model of the feather are constructed, and the numerical simulations are carried out to obtain the aerodynamic noise levels for each scale. Original model is found to reduce the noise level by 10 dBA, while two-fold increase in length dimensions reduces the noise by 12 dBA. Validation of numerical solution using wind tunnel experimental measurements is presented as well.

• 건축역사연구
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• 제2권2호
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• pp.89-106
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• 1993

Wherever Buddhism has flourished, there were stupas in the form of monuments which have their origin in the tumulm of prehistoric times. After the death of Buddha, his body was cremated following the Indian funeral custom. His ashes, which long reserved for the remains of nobles and holymen, were enshrined under such artificial hills of earth and brick. The Stupa was in origin a simple burial-mound. The form of the burial-mound was a symbolical or magic reconstruction of the imagined shape of the sky, like a dome covering the earth. The domical form of the earliest tumuli may have been concious replicas of the shape of the Vedic hut. There are relationships which may have originally existed between the stupa and West Asiatic monuments. Buddhist Stupa originally cosisted of an almost hemispherical tumulus(anda) and an altar-like structure (harmika) on its top, surmounted by one or several superimposed honorific umbrellas (hti, catta). This hemispherical form is associated with centralisation, lunar worship, mother earth, and Siva. Anda means a symbol of latent creative power, the harmika symbolizes the sanctuary enthroned aboved the world. The honorific umbrella, as an abstract imitation of the shade-giving tree is one of the chief solar symbols and that of enlightenment.

• Smart Structures and Systems
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• 제20권5호
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• pp.595-605
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• 2017

The present article reported the thermal buckling strength of the sandwich shell panel structure and subsequent improvement of the same by embedding shape memory alloy (SMA) fibre via a general higher-order mathematical model in conjunction with finite element method. The geometrical distortion of the panel structure due to the temperature is included using Green-Lagrange strain-displacement relations. In addition, the material nonlinearity of SMA fibre due to the elevated thermal environment also incorporated in the current analysis through the marching technique. The final form of the equilibrium equation is obtained by minimising the total potential energy functional and solved computationally with the help of an original MATLAB code. The convergence and the accuracy of the developed model are demonstrated by solving similar kind of published numerical examples including the necessary input parameter. After the necessary establishment of the newly developed numerical solution, the model is extended further to examine the effect of the different structural parameters (side-to-thickness ratios, curvature ratios, core-to-face thickness ratios, volume fractions of SMA fibre and end conditions) on the buckling strength of the SMA embedded sandwich composite shell panel including the different geometrical configurations.

• 한국기계가공학회지
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• 제11권6호
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• pp.195-200
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• 2012

In this study, parameters and requirements of an 120kW class monorail planetary gearbox was analysed and the adaptive planetary gearbox design was selected. The specification of the sun gear, planetary gear and carrier was set and the profile & lead was optimized. The mechanical efficiency of the optimized one and the original one was observed. Dynamo-tester system was used to observe the mechanical efficiency of the planetary gearbox. A dynamo unit was connected with the planetary gearbox which straightened through the motor by a coupling. The standard tooth shape planetary gearbox and modified tooth shape planetary gearbox were used as test pieces and the rotation speed was set from 600 to 6000rpm with 600rpm, 2.5min one step. In order to check the mechanical efficiency of the planetary gearbox, the tests were done as follows. 1) The power loss between driving motor and dynamo tester. 2) Temperature variation by different rotation speeds. 3) Noise variation by different rotation speeds.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권6호
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• pp.730-740
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• 2018

Hydrofoil is the direct component to generate thrust for underwater glider. It is significant to improve propulsion efficiency of hydrofoil. This study optimizes the shape of a hydrofoil using Free-Form Deformation (FFD) parametric approach and Surrogate-based Optimization (SBO) algorithm. FFD approach performs a volume outside the hydrofoil and the position changes of control points in the volume parameterize hydrofoil's geometric shape. SBO with adaptive parallel sampling method is regarded as a promising approach for CFD-based optimization. Combination of existing sampling methods is being widely used recently. This paper chooses several well-known methods for combination. Investigations are implemented to figure out how many and which methods should be included and the best combination strategy is provided. As the hydrofoil can be stretched from airfoil, the optimizations are carried out on a 2D airfoil and a 3D hydrofoil, respectively. The lift-drag ratios are compared among optimized and original hydrofoils. Results show that both lift-drag-ratios of optimized hydrofoils improve more than 90%. Besides, this paper preliminarily explores the optimization of hydrofoil with root-tip-ratio. Results show that optimizing 3D hydrofoil directly achieves slightly better results than 2D airfoil.