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Vortex-induced vibration of a long flexible cylinder in uniform cross-flow

  • Ji, Chunning;Peng, Ziteng;Alam, Md. Mahbub;Chen, Weilin;Xu, Dong
    • Wind and Structures
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    • v.26 no.5
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    • pp.267-277
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    • 2018
  • Numerical simulations are performed of a long flexible cylinder undergoing vortex-induced vibration at a Reynolds number of 500. The cylinder is pinned at both ends, having an aspect ratio of 100 (cylinder length to cylinder diameter) and a mass ratio of 4.2 (structural mass to displaced fluid mass). Temporal and spatial information on the cross-flow (CF) and in-line (IL) vibrations is extracted. High modal vibrations up to the $6^{th}$ in the CF direction and the $11^{th}$ in the IL direction are observed. Both the CF and IL vibrations feature a multi-mode mixed pattern. Mode competition is observed. The $2^{nd}$ mode with a low frequency dominates the IL vibration and its existence is attributed to a wave group propagating back and forth along the span. Distributions of fluid force coefficients are correlated to those of the CF and IL vibrations along the span. Histograms of the x'-y motion phase difference are evaluated from the total simulation time and a complete vibration cycle representing the standing or travelling wave pattern. Correlations between the phase difference and the vibrations are discussed. Vortex structures behind the cylinder show an interwoven near-wake pattern when the standing wave pattern dominates, but an oblique near-wake pattern when the travelling wave pattern prevails.

Data Type-Tolerant Component Model: A Method to Process Variability of Externalized Data (데이터 타입 무결성 컴포넌트 모델 : 외부화된 데이터 가변성 처리 기법)

  • Lim, Yoon-Sun;Kim, Myung;Jeong, Seong-Nam;Jeong, An-Mo
    • Journal of KIISE:Software and Applications
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    • v.36 no.5
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    • pp.386-395
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    • 2009
  • Business entities with which most service components interact are kind of cross-cutting concerns in a multi-layered distributed application architecture. When business entities are modified, service components related to them should also be modified, even though they implement common functions of the application framework. This paper proposes what we call DTT (Data Type-Tolerant) component model to process the variability of business entities, or externalized data, which feature modern application architectures. The DTT component model expresses the data variability of product lines at the implementation level by means of SCDTs (Self-Contained Data Types) and variation point interfaces. The model improves the efficiency of application engineering through data type converters which support type conversion between SCDTs and business entities of particular applications. The value of this model lies in that data and functions are coupled locally in each component again by allowing service components to deal with SCDTs only instead of externalized business eutities.

Study of Deterioration Improvement of Power Fuse (전력퓨즈의 열화현상 개선에 관한 연구)

  • Song, Jae-Ki;Kim, Hwan-Yong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.6
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    • pp.3827-3831
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    • 2014
  • This paper aims to solve the problem deterioration of power fuses. The deterioration of a power fuse is a cause of failure misoperation by a normal current flowing reduplicatively to fuse the element. An extension survey of a load feature rerating power fuse examined the power fuse deterioration removal, the cause of the deterioration of the power fuse, the front-after, and the thermal variation of the inside transformer room electric power equipment. The transformer showed an average improvement of $6[^{\circ}C]$. The temperature of the electrical line showed $7{\sim}8[^{\circ}C]$ improvement. The static condenser and direct reactor was $2{\sim}3[^{\circ}C]$ high-state maintenance the temperature and equipment syntonization relationship. In the subject of study $0.5{\sim}1.0[^{\circ}C]$ stabilizing three phase power fuse temperature differential was. Suggestion in the transformer room environment power equipment between the cause temperature happen elimination to deterioration of power fuse and temperature rise control.

Integrating Study of Kidney on Left & Life Gate on Right(左腎右命門) and Moving Energy between two kidneys(腎間動氣) (좌신우명문(左腎右命門)과 신간동기(腎間動氣)의 통합적 이해를 위한 연구)

  • Kim, Jin-Ho
    • Journal of Korean Medical classics
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    • v.26 no.4
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    • pp.253-266
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    • 2013
  • Objective : There was no attempt to understand Moving Energy between two kidneys(腎間動氣) and Kidney on Left & Life Gate on Right(左腎右命門) by integration progress. So I have faced to study based on two parts with concerning as clues. One is 'Life Right (左 右)' and the other is 'Between(間)'. Methods : Revealing the source of the origin, Nanjingbenyi(難經本義) is given on the basis. Take a close look at publications related to Nanjing(難經) which is about Kidney on Left & Life Gate on Right and Moving Energy between two kidneys. Take a close look at Kidney, the Life Gate and Moving Energy between two kidneys. Look see the three-dimensional uplift movement of Gi(氣). Results : In Neijing(內經) and Nanjing, the basic point of view for Kidney is the same. That is explained in line with attributes of convergence(收斂). 'Life Gate(命門)' is a term to express the divergence feature(發散機能) of kidney. Moving Energy between two kidneys is used to mean the mainspring of human body activity. The Gi in human body loses altitude turning left(左旋而下降) and gains height turning right(右旋而上升). Conclusion : Watching on functional aspect, there are two names for kidney. One is 'Kidney(腎)' which collects the losing altitude turning left and the other is 'Life Gate' which rises turning right. Moreover, the fundamental power that effectuate the uplift movement is Moving Energy between two kidneys. This kind model is a way that can be understood syntagmatically the Kidney on Left & Life Gate on Right and the Moving Energy between two kidneys without any gainsaying the original of Nanjing.

Band-Broadening Design of the Butler Matrix for V2X - 5.9 GHz Communication (V2X 차량 통신용 5.9 GHz 버틀러 매트릭스의 광대역화 설계)

  • Han, Dajung;Lee, Changhyeong;Park, Heejun;Kahng, Sungtek
    • Journal of Satellite, Information and Communications
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    • v.11 no.4
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    • pp.107-113
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    • 2016
  • In this paper, we suggest a design method of a wide-band Butler matrix working at 5.9 GHz for V2X communication antennas. Since V2X communication needs beam-forming and beam-steering antennas to make transportation systems, mobile comm platforms, saturated frequency-resources, and signal TX-and-RX smart, multi-functional, resolved, and efficient utmost, respectively, the proper Butler matrix and its radiating elements as a low-profile geometry are realized. The constitutive components of the basic Butler matrix of a narrow band are designed first. And then, it is extended to a wide-band version to make its frequency-shift less affected by the event of the antenna system being mounted on a car body. The beam-forming and beam-steering performance is presented as the common feature tagged along with the different bandwidths of the frequency responses as the comparison between the narrow- and wide-band cases.

Virtual Environment Interfacing based on State Automata and Elementary Classifiers (상태 오토마타와 기본 요소분류기를 이용한 가상현실용 실시간 인터페이싱)

  • Kim, Jong-Sung;Lee, Chan-Su;Song, Kyung-Joon;Min, Byung-Eui;Park, Chee-Hang
    • The Transactions of the Korea Information Processing Society
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    • v.4 no.12
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    • pp.3033-3044
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    • 1997
  • This paper presents a system which recognizes dynamic hand gesture for virtual reality (VR). A dynamic hand gesture is a method of communication for human and computer who uses gestures, especially both hands and fingers. Since the human hands and fingers are not the same in physical dimension, the produced by two persons with their hands may not have the same numerical values where obtained through electronic sensors. To recognize meaningful gesture from continuous gestures which have no token of beginning and end, this system segments current motion states using the state automata. In this paper, we apply a fuzzy min-max neural network and feature analysis method using fuzzy logic for on-line pattern recognition.

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3D LIDAR Based Vehicle Localization Using Synthetic Reflectivity Map for Road and Wall in Tunnel

  • Im, Jun-Hyuck;Im, Sung-Hyuck;Song, Jong-Hwa;Jee, Gyu-In
    • Journal of Positioning, Navigation, and Timing
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    • v.6 no.4
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    • pp.159-166
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    • 2017
  • The position of autonomous driving vehicle is basically acquired through the global positioning system (GPS). However, GPS signals cannot be received in tunnels. Due to this limitation, localization of autonomous driving vehicles can be made through sensors mounted on them. In particular, a 3D Light Detection and Ranging (LIDAR) system is used for longitudinal position error correction. Few feature points and structures that can be used for localization of vehicles are available in tunnels. Since lanes in the road are normally marked by solid line, it cannot be used to recognize a longitudinal position. In addition, only a small number of structures that are separated from the tunnel walls such as sign boards or jet fans are available. Thus, it is necessary to extract usable information from tunnels to recognize a longitudinal position. In this paper, fire hydrants and evacuation guide lights attached at both sides of tunnel walls were used to recognize a longitudinal position. These structures have highly distinctive reflectivity from the surrounding walls, which can be distinguished using LIDAR reflectivity data. Furthermore, reflectivity information of tunnel walls was fused with the road surface reflectivity map to generate a synthetic reflectivity map. When the synthetic reflectivity map was used, localization of vehicles was able through correlation matching with the local maps generated from the current LIDAR data. The experiments were conducted at an expressway including Maseong Tunnel (approximately 1.5 km long). The experiment results showed that the root mean square (RMS) position errors in lateral and longitudinal directions were 0.19 m and 0.35 m, respectively, exhibiting precise localization accuracy.

A Variable Parameter Model based on SSMS for an On-line Speech and Character Combined Recognition System (음성 문자 공용인식기를 위한 SSMS 기반 가변 파라미터 모델)

  • 석수영;정호열;정현열
    • The Journal of the Acoustical Society of Korea
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    • v.22 no.7
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    • pp.528-538
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    • 2003
  • A SCCRS (Speech and Character Combined Recognition System) is developed for working on mobile devices such as PDA (Personal Digital Assistants). In SCCRS, the feature extraction is separately carried out for speech and for hand-written character, but the recognition is performed in a common engine. The recognition engine employs essentially CHMM (Continuous Hidden Markov Model), which consists of variable parameter topology in order to minimize the number of model parameters and to reduce recognition time. For generating contort independent variable parameter model, we propose the SSMS(Successive State and Mixture Splitting), which gives appropriate numbers of mixture and of states through splitting in mixture domain and in time domain. The recognition results show that the proposed SSMS method can reduce the total number of GOPDD (Gaussian Output Probability Density Distribution) up to 40.0% compared to the conventional method with fixed parameter model, at the same recognition performance in speech recognition system.

A Study on Stereo Matching Algorithm using Disparity Space Image (시차공간영상을 이용한 스테레오 영상 정합에 관한 연구)

  • Lee, Jong-Min;Kim, Dae-Hyun;Choi, Jong-Soo
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.41 no.6
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    • pp.9-18
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    • 2004
  • This paper proposes a new and simple stereo matching algorithm using the disparity space image (DSI) technique. First of all, we detect some salient feature points on each scan-line of the image pair and set the matching area using those points and define a simple cost matrix. And we take advantage of matching by pixel-by-pixel instead of using the matching window. While the pixel-by-pixel method boost up the speed of matching, because of no using neighbor information, the correctness of the matching may not be better. To cover this point, we expand the matching path using character of disparity-space-image for using neighbor information. In addition, we devise the compensated matching module using the volume of the disparity space image in order to improve the accuracy of the match. Consequently, we can reduce mismatches at the disparity discontinuities and can obtain the more detailed and correct disparity map.

A Study on the Fashion Trends of a Popular Star (대중스타의 패션 트렌드에 관한 연구)

  • Lee, Eun-Sook
    • Journal of the Korea Fashion and Costume Design Association
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    • v.10 no.1
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    • pp.69-78
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    • 2008
  • A new coinage which calls a modern was appeared variously by values, taste, feature of lifestyle and the meaning of a new coinage has influence in the change of lifestyle. Particularly a popular star is a person who situates in the center of a new coinage, his role, behavior, and appearance have great influence in the birth of a new coinage. He is a fashion leader as well as the object of fashion imitation to the new generation being sensitive for fashion. As his fashion is appeared with important fashion icon in fashion market, fashion companies have developed actively star marketing marking him as an advertising model. Therefore, because the fashion trends of a popular star introduce season's fashion trends and can be important factor forecasting fashion behavior of consumer, this study aims at analysis for fashion trends of a popular star including a public entertainer. The dates of this study were collected by TV drama, internet, and magazines, etc. The fashion trends were divided into feminine fashion trend, sexy fashion trend, tomboy fashion trend, and retro fashion trend. Feminine fashion trend was based on feminity but it was classified in masculine look, simple look, chic look, and natural & romantic look according to the standard of a transformation of feminine image. Sexy fashion trend was divided into two sexy images according to the method wrapping oneself in a dress and the method exposing a specific body part. Tomboy fashion trend could be the immature boyish style which concealed bust or hip or pelvis symbolizing feminity. Retro fashion trend could be style being based on 1980's style and Y line. Fashion items as leggings, baby doll dress, tunic style, dot pattern, garsonne look were come into fashion.

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