• Title/Summary/Keyword: rotors

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Color Selection and Arrangement in Relics of Women's Jeogori in Modern Korea (근대이후 여자저고리 실물의 색채와 배색에 관한 연구)

  • Park, Chun-Sun;Cho, Woo-Hyun;Lee, Ho-Jung
    • Journal of the Korean Society of Costume
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    • v.59 no.2
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    • pp.1-17
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    • 2009
  • This study is to understand the characteristics of Korean Women's Jeogories in modern times on the changes of its color and coloration over the time. The research was that the characteristics of the costumes produced in modern times (18902000) can be categorized into six periods according to the change of times. 1106 women's Jeogories were researched intensively in order to understand them, the conclusions are following: When the Chi-Square Test is applied to conduct cross analγsis of the said six periods divided on the basis of relevant theories, it is found that there is just partial difference in the hues in1890-1959 while there has been a big change in the hues of all Jeogories since 1960. It also seems that such a sudden change In hues took place till the end of the 1970s but there have been no significant difference and no distinct changes in hues sin[e the 1980s. As for color tones, high luminosity and low chroma hues were mainly used in all periods, but low luminosity and high chroma hues have been frequently used since the 1960s. It indicates that the long-used conventional and traditional colors gave way to various colors which were freely applied according to the tendency of individualism In the selection of colors as well. As for the coloration, one-color arrangement was predominant in white clothes while the combination of main color Y and supplementary rotor R was overwhelming in two-color arrangement. After the 1960s, not just the five major rotors but diverse colors, including bluish green, dark blue, were used, even varied patterns for linings.

Application of Fashion Design to Mobile-Phone Game Character's Dress Design (모바일폰 게임 캐릭터 의상 디자인을 위한 패션 디자인 활용연구)

  • Lee, Min-Sun
    • Journal of the Korean Society of Costume
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    • v.57 no.3 s.112
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    • pp.63-77
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    • 2007
  • The purpose of this study is to apply fashion design to developing dress design of mobile-phone game characters. As for the research methodology, first, market research has been carried out to extract main images from dress designs of game characters and to understand their socio-cultural meanings. Second, the fashion design, which ran be compared to the extracted images of game characters were selected. Third, analyses were done to find out the gap between the game character's dress designs and the fashion designs. The main images of game characters are revealed as erotic, romantic, heroic, grotesque. These images have been formed by psychological and socio-cultural effects such as stimulation, empathy, compensation, increase of female game player. The differences between the game character's dresses and the fashion designs are as follows; With regard to style, game dresses have silhouette distinguished from background, but fashion collection have blurred silhouette. In the aspect of color, while strong colors are mainly used in game dress, neutral rotors are preferred in fashion collection. As for texture, the expression of 'textures in game character's dress is so far limited due to the insufficient level of the concerned technology. However, the fashion design applying drape of fabrics are well-developed. Mobile-phone game players want reality in game design. Therefore, the effort to overcome the gaps between game dress and fashion design can contribute to the growth of game character design.

Accuracy Simulation of Precision Rotary Motion Systems (회전운동 시스템의 정밀도 시뮬레이션 기술)

  • Hwang, Joo-Ho;Shim, Jong-Youp;Hong, Seong-Wook;Lee, Deug-Woo
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.3
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    • pp.285-291
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    • 2011
  • The error motion of a machine tool spindle directly affects the surface errors of machined parts. The error motions of the spindle are not desired errors in the three linear direction motions and two rotating motions. Those are usually due to the imperfect of bearings, stiffness of spindle, assembly errors, external force or unbalance of rotors. The error motions of the spindle have been needed to be decreased to desired goal of spindle's performance. The level of error motion is needed to be estimated during the design and assembly process of the spindle. In this paper, the estimation method for the five degree of freedom (5 D.O.F) error motions of the spindle is suggested. To estimate the error motions of the spindle, waviness of shaft and bearings, external force model was used as input data. And, the estimation models are considering geometric relationship and force equilibrium of the five degree of the freedom. To calculate error motions of the spindle, not only imperfection of the shaft, bearings, such as rolling element bearing, hydrostatic bearing, and aerostatic bearing, but also driving elements such as worm, pulley, and direct driving motor systems, were considered.

Performance Characteristics of a Partially Admitted Small Mixed-Type Turbine (부분분사에서 작동하는 소형 사류형 터빈에서의 성능특성에 관한 연구)

  • Cho, Chong-Hyun;Kim, Chae-Sil;Paeng, Jin-Gi;Cho, Soo-Yong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.9
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    • pp.889-898
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    • 2009
  • A mixed-type turbine was adopted and the rotor outer diameter was 108 mm. Turbine rotors were designed to the axial-type blade because the turbine operated at a low partial admission rate of 1.7-2.0% with two stages. Performance characteristics were studied when the spouting from the nozzle was toward radially inward or outward direction. Additionally, the effect at each stage of the rotor was measured. For comparing with each turbine performance, properties were measured based on various rotational speeds. Measured net specific torque was used to compare with the turbine system performance. On the mixed-type turbine, better performance was obtained when the operating air spouted toward radially inward direction. The specific torque was increased by 7.8% from using the second stage although its effect depended on the rotational speed.

Development of Dynamic Balancing Techniques of a Rotor System Using Genetic Algorithm (유전자 알고리즘을 적용한 로터 시스템의 동적 밸런싱 기법 개발)

  • Kwon, Hyuck-Ju;Yu, Young-Hyun;Jung, Sung-Nam;Yun, Chul-Yong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.12
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    • pp.1162-1169
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    • 2010
  • The dynamic balancing of a rotor system is needed to alleviate the imbalances originating from various sources encountered during blade manufacturing processes and environmental factors. This work aims at developing a comprehensive analysis system which consists of cumulative module of test D/B and selection of optimal control parameters. This system can be used for the dynamic balancing of helicopter rotors based on tracking results from the whirl tower test. For simplicity of the analysis, a linear relation is assumed between the balancing input parameters and the blade track responses leading to influence coefficients and thereby the rotor system identification is made. In addition, the balancing parameters of the individual blades are sought using the genetic algorithm and the effectiveness of the proposed method is demonstrated in comparison with the test results.

Aerodynamic Performance Prediction of a Counter-rotating Wind Turbine System with Wake Effect (후류영향을 고려한 상반회전 풍력발전 시스템의 공력성능 예측에 관한 연구)

  • Dong, Kyung-Min;Jung, Sung-Nam
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.7
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    • pp.20-28
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    • 2002
  • In this paper, the aerodynamic performance prediction of a 30kW counter-rotating (C/R) wind turbine system has been made by using the momentum theory as well as the two-dimensional quasi-steady strip theory with special care on the wake and the post-stall effects. In order to take into account the wake effects in the performance analysis, the wind tunnel test data obtained for a scaled blade are used. Both the axial and rotational inductions behind the auxiliary rotors are determined through the wake model. In addition, the optimum chord and twist distributions along the blades are obtained from the Glauert's optimum actuator disk model considering the Prandtl's tip loss effect. The performance results of the counter-rotating wind turbine system are compared with those of the conventional single rotor system and demonstrated the effectiveness of the counter-rotating wind turbine system.

Dynamic Modeling and Stabilization of a Tri-Ducted Fan Unmanned Aerial Vehicles using Lyapunov Control (삼중 덕티드 팬 비행체 운동모델링 및 리아푸노프 제어를 이용한 안정화)

  • Na, Kyung-Seok;Won, Dae-Hee;Yoon, Seok-Hwan;Sung, Sang-Kyung;Ryu, Min-Hyoung;Cho, Jin-Soo;Lee, Young-Jae
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.7
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    • pp.574-581
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    • 2012
  • Because of the exposed blade, the UAV using the rotors entail the risks during operation. While a wrapped duct around the fan blades reduces risks, it is a higher thrust performance than the same power load rotor. In this paper, for applying advantages of a ducted fan, the tri-ducted fan air vehicle configuration is proposed. The vehicle has three ducted fans. Two of them are the same shape and size and the third one is the smaller. It is possible to control a rapid attitude stability using thrust vector control. The equations of motion of the tri-ducted fan were derived. Lyapunov control input was applied to the system and stable inputs were derived. A nonlinear simulation was fulfilled by using parameters of a prototype vehicle. It verified a stable attitude and analyzed results.

Development of an Automated Integrated Design System for Gerotor Pumps with Multiple Profiles(Ellipse and Involute) (타원.인벌루트 조합 형상을 갖는 지로터 펌프의 통합적 설계 자동화 시스템 개발)

  • Moon, Hyun-Ki;Jung, Sung-Yuen;Bae, Jun-Ho;Chang, Young-June;Kim, Chul
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.9
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    • pp.67-77
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    • 2010
  • An internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular, the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobe with elliptical and involute shapes, while the inner rotor profile is determined as conjugate to the other. And the integrated design system which is composed of three main modules has been developed through AutoLISP under AutoCAD circumstance plus CFD-ACE+. It generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. CFD simulation results show trends similar to those carried out in experiments, and a quantitative comparison is presented. Results obtained from the automotive integrated design system enable the designer and manufacturer of oil pump to be more efficient in this field.

Design and Construction of 10 kWh Class Flywheel Energy Storage System (10 kWh급 플라이휠 에너지 저장 시스템 설계 및 제작)

  • Jung, S.Y.;Han, S.C.;Han, Y.H.;Park, B.J.;Bae, Y.C.;Lee, W.R.
    • Progress in Superconductivity
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    • v.13 no.1
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    • pp.40-46
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    • 2011
  • A superconductor flywheel energy storage system (SFES) is an electro-mechanical battery which transforms electrical energy into mechanical energy for storage, and vice versa. A 10 kWh class flywheel energy storage system (FESS) has been developed to evaluate the feasibility of a 35 kWh class SFES with a flywheel Ip/It ratio larger than 1. The 10 kWh class FESS is composed of a main frame, a composite flywheel, active magnetic dampers (AMDs), a permanent magnet bearing, and a motor/generator. The flywheel of the FESS rotates at a very high speed to store energy, while being levitated by a permanent magnetic bearing and a pair of thrust AMDs. The 10 kWh class flywheel is mainly composed of a composite rotor assembly, where most of the energy is stored, two radial and two thrust AMD rotors, which dissipate vibration at critical speeds, a permanent magnet rotor, which supports most of the flywheel weight, a motor rotor, which spins the flywheel, and a central hollow shaft, where the parts are assembled and aligned to. The stators of each of the main components are assembled on to housings, which are assembled and aligned to the main frame. Many factors have been considered while designing each part of the flywheel, stator and frame. In this study, a 10 kWh class flywheel energy storage system has been designed and constructed for test operation.

Evaluation of Datum Unit for Diagnostics of Journal-Bearing Systems (저널베어링의 이상상태 진단을 위한 데이텀 효용성 평가)

  • Jeon, Byungchul;Jung, Joonha;Youn, Byeng D.;Kim, Yeon-Whan;Bae, Yong-Chae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.8
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    • pp.801-806
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    • 2015
  • Journal bearings support rotors using fluid film between the rotor and the stator. Generally, journal bearings are used in large rotor systems such as turbines in a power plant, because even in high-speed and load conditions, journal bearing systems run in a stable condition. To enhance the reliability of journal-bearing systems, in this paper, we study health-diagnosis algorithms that are based on the supervised learning method. Specifically, this paper focused on defining the unit of features, while other previous papers have focused on defining various features of vibration signals. We evaluate the features of various lengths or units on the separable ability basis. From our results, we find that one cycle datum in the time-domain and 60 cycle datum in the frequency domain are the optimal datum units for real-time journal-bearing diagnosis systems.