• Title/Summary/Keyword: Desirable Configuration

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A Study on the Architectural Characteristics of Vuoksenniska Church (부오크세니스카 교회의 건축 특성에 관한 연구)

  • Chung, Tae-Yong
    • Korean Institute of Interior Design Journal
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    • v.18 no.1
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    • pp.19-26
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    • 2009
  • Aalto designed his own modern architecture in comparison with other modern architects of his days. It is because Aalto went beyond the principle of dogmatic functionalism based on his attitude not to copy images of functionalism but to fulfill function of the building. He decided architectural form and space according to logical basis including the effective use of light and sound. Vuoksenniska church, as is called the most exceptional and notable church in his works, was designed based on the fulfillment of program. As he knew that the program needed the extension of the main church space into social areas, he put emphasis on individuality of space rather than the wholeness of space. Sound and light analysis of Vuoksenniska church shows that Aalto tried to have adequate environment of each space at the start and Integrate them later. The spatial configuration of Vuoksenniska church shows that the individuality of space has priority over the wholeness of spaces. Discordance between roof form and ceiling is the best example for this matter. Aalto designed various windows that have different sizes, figure and location to induce desirable light for each space of the church. He also adjusted the shape of the ceiling and the angle of wall for a effective sound transmission. This result indicates that he knew the activity of the church is normally confined to one weekly morning and the whole space Is hardly used as a religious purpose.

Disturbance estimation of optical disc by closed loop output estimator (페루프 외란 검출기를 통한 광디스크 외란 측정)

  • Park, Jin-Young;Chun, Chan-Ho;Jun, Hong-Gul;Lee, Moon-Noh;Hyunseok Yang;Park, Young-Pil
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.1166-1171
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    • 2001
  • The method for output disturbance estimation is proposed. In this method, output disturbance is estimated from the closed loop system dynamics using the output and control input signals. In the closed-loop output-disturbance estimator, precise system identification is required to reduce estimation error. The realization of estimator was done by the DSP board (DSPl103), and disturbance estimation in various environments was performed: change of rotation speed, media feature and spindle motor with (or without) auto-ball balancing system (ABS). From these experiments, the disturbance characteristics of ODD under various conditions are analyzed, and the desirable servo loop configuration based these results is proposed.

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Development of Buckling Restrained Brace Laterally Supported by Semicircular Springs (반원형 스프링으로 횡지지된 건식형 좌굴방지가새의 개발)

  • Park, Keum Sung;Lee, Sang Sup;Hong, Sung Yub;Bae, Kyu Woong
    • Journal of Korean Society of Steel Construction
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    • v.26 no.6
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    • pp.549-558
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    • 2014
  • Buckling restrained braces(BRBs) developed as a seismic protection element, hysteretic damper, have been investigated in America and Japan mainly. BRBs are composed of a steel core and concrete-filled steel casing. It is one of the major causes of drop in productivity to fill the steel casing with concrete. To improve this problem, the BRB is introduced in which the steel core is restrained with a pair of semicircular springs. In this paper, the numerical and analytical investigation about the desirable configuration for a semicircular spring is presented. Firstly, the stiffness and strength of semicircular spring is determined theoretically to buckle into a very high-order modes. Then, the required stiffness and strength are calculated under the practical design conditions and considered as reference values to find a proper configuration. The material strength and thickness of semicircular spring are chose from the finite element analysis for 5 semicircular springs with varying height. Finally, the nonlinear buckling analysis of BRB with proper semicircular springs shows that the bucking strength of the whole BRB is very similar to the strength of steel core with length between semicircular springs.

Dynamic Characteristics of CFRP Structure Member According to Change the Stacking Angle and Shape (적층각 및 형상 변화에 따른 CFRP 구조부재의 동적 특성)

  • Yeo, In-Goo;Choi, Ju-Ho;Yang, In-Young
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.3
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    • pp.388-393
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    • 2013
  • Carbon fiber reinforced plastic (CFRP) has many desirable qualities, including being lightweight and very strong. These characteristics have led to its use in applications ranging from small consumer products to vehicles. Circular and square CFRP members were fabricated using 8ply unidirectional prepreg sheets stacked at different angles ($[+15^{\circ}/-15^{\circ}]_4$, $[+45^{\circ}/-45^{\circ}]_4$ and $[90]_8$, where $0^{\circ}$ coincides with the axis of the member). Based on the collapse characteristics of a CFRP circular member, the collapse characteristics and energy absorption capability were analyzed. Impact collapse tests were carried out for each section member. In this study, the impact energies at crossheads speeds of 5.52 m/s, 5.14 m/s and 4.57 m/s were 611.52 J, 529.2 J and 419.44 J (circular member) 2.16 m/s, 1.85 m/s and 1.67 m/s are 372.4 J, 274.4 J and 223.44 J (square member). The purpose is to experimentally examine the absorption behavior and evaluation the strength in relation to changes in the stacking configuration when the CFRP circular members with different stacking configurations were exposed to various impact velocities. In addition, the dynamic characteristics were considered.

Analysis of Sequence Impedances of 345kV Cable Transmission Systems (실계통 345kV 지중송전선 대칭좌표 임피던스의 해석)

  • Choi, Jong-Kee;Ahn, Yong-Ho;Yoon, Yong-Beum;Oh, Sei-Ill;Kwa, Yang-Ho;Lee, Myoung-Hee
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.7
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    • pp.905-912
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    • 2013
  • Power system fault analysis is commonly based on well-known symmetrical component method, which describes power system elements by positive, negative and zero sequence impedance. In case of balanced fault, such as three phase short circuit, transmission line can be represented by positive sequence impedance only. The majority of fault in transmission lines, however, is unbalanced fault, such as line-to-ground faults, so that both positive and zero sequence impedance is required for fault analysis. When unbalanced fault occurs, zero sequence current flows through earth and skywires in overhead transmission systems and through cable sheaths and earth in cable transmission systems. Since zero sequence current distribution between cable sheath and earth is dependent on both sheath bondings and grounding configurations, care must be taken to calculate zero sequence impedance of underground cable transmission lines. In this paper, conventional and EMTP-based sequence impedance calculation methods were described and applied to 345kV cable transmission systems (4 circuit, OF 2000mm2). Calculation results showed that detailed circuit analysis is desirable to avoid possible errors of sequence impedance calculation resulted from various configuration of cable sheath bonding and grounding in underground cable transmission systems.

Computational Analysis of Three-Dimensional Turbulent Flow Around Magnetically Levitated Train Configurations in Elevated Track Proximity (고가궤도에 근접한 자기부상열차 형상 주위의 3차원 난류유동에 대한 수치해석)

  • Maeng, J.S.;Yang, S.Y.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.1
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    • pp.9-25
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    • 1994
  • In the present study, the Reynolds-averaged Navier-Stokes equations, together with the equations of the $k-{\varepsilon}$ model of turbulence, were solved numerically in a general body-fitted coordinate system for three-dimensional turbulent flows around the six basic shapes of the magnetically levitated train(MAGLEV). The numerical computations were conducted on the MAGLEV model configurations to provide information on shapes of this type very near the elevated track at a constant Reynolds number of $1.48{\times}10^{6}$ based on the body length. The coordinate system was generated by numerically solving a set of Poisson equations. The convective transport equations were discretized using the finite-analytic scheme which employed analytic solutions of the locally-linearized equations. A time marching algorithm was employed to enable future extensions to be made to handle unsteady and fully-elliptic problems. The pressure-velocity coupling was treated with the SIMPLER-algorithm. Of particular interests were wall effect by the elevated track on the aerodynamic forces and flow characteristics of the six models calculated. The results indicated that the half-circle configuration with extended sides and with smooth curvature of sides was desirable because of the low aerodynamic forces and pitching moment. And it was found that the separation bubble was occured at wake region in near the elevated track.

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A methodology for design of metallic dampers in retrofit of earthquake-damaged frame

  • Zhang, Chao;Zhou, Yun;Weng, Da G.;Lu, De H.;Wu, Cong X.
    • Structural Engineering and Mechanics
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    • v.56 no.4
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    • pp.569-588
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    • 2015
  • A comprehensive methodology is proposed for design of metallic dampers in seismic retrofit of earthquake-damaged frame structures. It is assumed that the metallic dampers remain elastic and only provide stiffness during frequent earthquake (i.e., earthquake with a 63% probability of exceedance in 50-year service period), while in precautionary earthquake (i.e., earthquake with a 10% probability of exceedance in 50-year service period), the metallic dampers yield before the main frame and dissipate most of the seismic energy to either prevent or minimize structural damages. Therefore by converting multi-story frame to an equivalent single-degree-of-freedom system, the added stiffness provided by metallic dampers is designed to control elastic story drifts within code-based demand under frequent earthquake, and the added damping with the combination of added stiffness influences is obtained to control structural stress within performance-based target under precautionary earthquake. With the equivalent added damping ratio, the expected damping forces provided by metallic dampers can be calculated to carry out the configuration and design of metallic dampers along with supporting braces. Based on a detailed example for retrofit of an earthquake-damaged reinforced concrete frame by using metallic dampers, the proposed design procedure is demonstrated to be simple and practical, which can not only meet current China's design codes but also be used in retrofit design of earthquake-damaged frame with metallic damper for reaching desirable performance objective.

Experimental Study on Pre-Stresses Steel Beam (Pre-stress를 도입한 Steel Beam에 관한 실험적 연구)

  • 조진구;박병기
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.17 no.4
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    • pp.3921-3930
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    • 1975
  • This research was carried out to investigate several mechanical characteristics of pre-stressed steel beams. The configuration of specimens used for this study were as follows; a cover plate having permissible fiber stress of 4,000 kg/$\textrm{cm}^2$ was welded at bottom having the allowable bending stress 2500 kg/$\textrm{cm}^2$ steel beam, the section ratios of pre-stressed steel beam and cover plate were 0.5 and 0.6. Adopted pre-stresses were 0%, 50%, and 100% of an allowable fiber stress of a steel beam. The results obtained from the study may be summarized as follows; 1. The elastic range of a beam was increased by the application of pre-stress to the beam, which leads to a lighter section. 2. The permissible moment capacity of a pre-stressed steel beam was greated than that of a steel beam without pre-stressing. 3. The equivalent allowable stress induced by adopting the different section ratio of pre-stressed beam to cover plate were figured out 4. The optimum value of section ratio of beam and cover plate was 0.3 to 0.4 in case of a 1.5m span composite beam, a combination of an allowable stress 2,500kg/$\textrm{cm}^2$ steel beam and a permissible fiber stress 4,000 kg/$\textrm{cm}^2$ steel cover plate, was used. 5. The magnitude of the pre-stress was desirable to be same as the allowable stress of a steel beam. 6. It was concluded that if the construction techniques in the field are developed and improved, the practicing of pre-stress to the steel structure has a promising future.

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A Study on the Drum Water Level Versus Incoming Water Quantities for Small Vertical Hydraulic Water Turbine Plant (종축소수력발전소의 인입수량과 드럼수위와의 관계에 관한 연구)

  • Che, Gyu-Shik;Jung, Ju-One
    • Journal of Advanced Navigation Technology
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    • v.18 no.3
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    • pp.254-260
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    • 2014
  • We studied water level rising of drum versus time in the small hydraulic vertical water turbine system in this paper. The water level rises continuously up to a certain point with the passage of time if the constant incoming water is supplied, while it stops rising and maintains equilibrium state without any more rising because it increases position energy and evatually makes outgoing velocity and outgoing water quantities of runner area. The water level of drum is determined independent of size, height, width, figure of drum or runner configuration. It comes out that the water level is dependent only on the incoming and outgoing water quantities, and the output power has similar behavior. Therefore, desirable water level and output power are not available unless incoming water quantities is abundant. We validate this phenomina through applyng our methodolgies to the real small hydraulic vertical water turbine system under constructing and testing in industrial facilities in Korea.

A study on the Optimum Design Configuration of Passive Solar TI-wall system (투명단열재가 적용된 축열벽 시스템의 최적구성 선정에 관한 연구)

  • Kim, Byoung-Soo;Yoon, Jong-Ho;Yoon, Yong-Jin;Baek, Nam-Choon
    • KIEAE Journal
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    • v.3 no.2
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    • pp.37-44
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    • 2003
  • The aim of this study was to analyze the thermal performance through Test-Cell of TI-wall in domestic climate. This study was carried out as follows: 1) The TI-wall was studied for ability to reduce heat loss through the building envelope and analyzed to TIM properties. 2) Test models of TI-wall were designed through the investigation of previous paper and work, measured for winter and spring, and the thermal effects were analyzed. The type of the TIM used in test model is small-celled(diameter 4mm and thickness 50mm) capillary and cement brick(density $1500kg/m^3$) was used by thermal mass. 3) Test-cell of TI-wall was calibrated from measured data and the dynamic simulation program ESP-r 9.0. In these simulations, the measured climate conditions of TaeJon were used as outdoor conditions, and the simulation model of Test-cell was developed. 4) The sensitivity analysis is executed in various aspects with standard weather files and ESP-r 9.0, and then most suitable system of TI-wall are predicted. Finally, The suitable system of TI-wall was analysed according to sizes of air gap, kinds, thickness, and the surface absorption of therm wall. The result is following. In TI-wall, Concrete is better than cement brick, at that time the surface absorption is 95%, and the most efficient thickness is 250mm. As smaller of a air gap, as reducer of convection heat loss, it is efficient for heating energy. However, ensuring of a air gap at least more than 50mm is desirable for natural ventilation in Summer.