• Title/Summary/Keyword: radius problem

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Cross-talk Cancellation Algorithm for 3D Sound Reproduction

  • Kim, Hyoun-Suk;Kim, Poong-Min;Kim, Hyun-Bin
    • ETRI Journal
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    • v.22 no.2
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    • pp.11-19
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    • 2000
  • If the right and left signals of a binaural sound recording are reproduced through loudspeakers instead of a headphone, they are inevitably mixed during their transmission to the ears of the listener. This degrades the desired realism in the sound reproduction system, which is commonly called 'cross-talk.' A 'cross-talk canceler' that filters binaural signals before they are sent to the sound sources is needed to prevent cross-talk. A cross-talk canceler equalizes the resulting sound around the listener's ears as if the original binaural signal sound is reproduced next to the ears of listener. A cross-talk canceler is also a solution to the problem-how binaural sound is distributed to more than 2 channels that drive sound sources. This paper presents an effective way of building a cross-talk canceler in which geometric information, including locations of the listener and multiple loudspeakers, is divided into angular information and distance information. The presented method makes a database in an off-line way using an adaptive filtering technique and Head Related Transfer Functions. Though the database is mainly concerned about the situation where loudspeakers are located on a standard radius from the listener, it can be used for general radius cases after a distance compensation process, which requires a small amount of computation. Issues related to inverting a system to build a cross-talk canceler are discussed and numerical results explaining the preferred configuration of a sound reproduction system for stereo loudspeakers are presented.

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Stability Analysis of a Fluid Dynamic Journal Bearing Considering the Tilting Motion (틸팅 운동을 고려한 유체 동압 베어링의 안정성 해석)

  • Kim, Myung-Gyu;Jang, Gun-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.11a
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    • pp.394-400
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    • 2008
  • This paper presents an analytical method to investigate the stability of FDBs (fluid dynamic bearings) considering the tilting motion. The perturbed equations of motion are derived with respect to translational and tilting motion for the general rotor-bearing system with five degrees of freedom. The Reynolds equations and their perturbed equations are solved by using the FEM in order to calculate the pressure, load capacity, and the stiffness and damping coefficients. This research introduces the radius of gyration to the equations of notion in order to express the mass moment of interia with respect to the critical mass. Then the critical mass of FDBs is determined by solving the eigenvalue problem of the linear equations of motion. This research is numerically validated by comparing the stability chart of FDBs with the time response of the whirl radius obtained from the direct integration of the equations of motion. This research shows that the tilting motion is one of the major design considerations to determine the stability of rotating system. It also shows that the stability of FDBs considering only translation is overestimated in comparison with the stability of FDBs considering both translational and tilting motion.

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A Study On Steering System for Mobile Robot with Permanent Magnet Wheels (영구자석 바퀴를 이용한 이동 로봇의 조향 시스템 연구)

  • Kim Jin-Gak;Yi Hwa-Cho;Han Seung-Chul
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.311-312
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    • 2006
  • In this paper, steering systems for mobile robot with permanent magnet wheels are discussed. The mobile robot with permanent magnet wheels can have three different types of steering and driving configurations; two-wheels, three-wheels, four-wheels. By a Two-WD(Wheel Driving) system, driving and steering characteristics are controlled by ratio of each wheel speeds. Three-WD system is steered by a front wheel and driven by rear wheels. Four-WD system has better stability than two wheel system. Usually the permanent magnet wheel has nearly none slip. Thus turning radius of the mobile robot with three-WD and four-WD System will be increased and the steering and driving system will be complicated. To solve this problem, two magnet wheels with two dummy wheels are used in this study. fuming radius of the developed mobile robot is small and the structure of the robot is simple. It is possible to move forward, backward, to turn left and right, and to rotate freely with two-WD. This study proved that two-WD system is very suitable fur the mobile robot with permanent magnet wheels.

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A Study on Solving Triangle Construction Problems Related with Radius of Escribed Circle Using Algebraic Method (대수적 방법을 이용한 방접원에 관련된 삼각형 작도문제의 해결 연구)

  • Gong, Seon-Hye;Han, In-Ki
    • Journal of the Korean School Mathematics Society
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    • v.11 no.3
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    • pp.399-420
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    • 2008
  • In this paper we solve various triangle construction problems related with radius of escribed circle using algebraic method. We describe essentials and meaning of algebraic method solving construction problems. And we search relation between triangle construction problems, draw out 3 base problems, and make hierarchy of solved triangle construction problems. These construction problems will be used for creative mathematical investigation in gifted education.

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A Study of Design for Hot Tool to Minimize Radius of Heat Affected Zone in Rapid Heat Ablation process (쾌속 열용삭 공정에서 열반경 최소화를 위한 열 공구 설계에 관한 연구)

  • Kim Hyo-Chan;Lee Sang-Ho;Park Seung-Kyo;Yang Dong-Yol
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.7 s.184
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    • pp.177-186
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    • 2006
  • In order to realize a three-dimensional shape on CAD, the machining process has been widely used because it offers practical advantages such as precision and versatility. However, the traditional machining process needs a large amount of time in cutting a product and the remained material causes trouble such as inconvenience due to cleaning process. Therefore, a new rapid manufacturing process, Rapid Heat Ablation process (RHA) using the hot tool, has been developed. In this paper, the hot tool for RHA process is designed to minimize radius of heat affected zone. TRIZ well-known as creative problem solving method is applied to overcome the contradictive requirements of the hot tool. For the detailed design of the hot tool, numerical model is established with several assumptions. In order to verify the numerical results, surface temperature of the hot tool is measured with K-type thermocouple at the predetermined location. Numerical and experimental results show that the devised hot tool fulfils its requirements. The practicality and effectiveness of the designed hot tool have been verified through experiments.

Evaluation on the Horizontal Alignment of Road Centerline using GIS Programming (GIS 프로그래밍을 이용한 도로중심선 평면선형 평가)

  • Kim, Dong-Ki;Choi, Se-Hyu
    • International Journal of Highway Engineering
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    • v.14 no.1
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    • pp.1-8
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    • 2012
  • The horizontal alignment of road is deeply related with the stability of the road and traffic capacity. It is necessary to analyze horizontal alignment of road accurately for efficient maintenance of the road and relevance judgment about the standard. Recently the study on horizontal alignment of road using Lidar data and GPS was concluded, but they were many problem analyzing horizontal alignment radius of curvature in wide area. In this study, the tool which the radius of curvature can evaluate the suitability about "Rules about the Road Structure & Facilities Standards" by using center lines of the road of the digital map tries to implement on GIS. The interface was designed and implemented which can automatically estimate the Road Centerline Horizontal Alignment by using $ESRI^{(R)}$ $ArcObject^{TM}$.

Extension for Downward Continuation of the Method of "Upward Continuation of Potential Field on Spherical Patch Area" ("구면부분지역에서 퍼텐셜마당의 상향연속"의 하향연속 확장적용)

  • Na, Sung-Ho;Chung, Tae Woong;Shin, Young Hong
    • Geophysics and Geophysical Exploration
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    • v.16 no.1
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    • pp.59-62
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    • 2013
  • We formerly reported a new method for the upward continuation of potential field on spherical patch area including Earth's curvature, which has been neglected in most studies on rectangular area with flat Earth assumption. This new method is applicable to downward continuation as well by only assigning corresponding value for the ratio of two radii; $r_2/r_1$, i.e., target radius $r_2$ versus datum radius $r_1$. In addition, the inherent problem of this method due to spherical surface geometry is described, and its one possible remedy is given.

A Study on Improvement of LTE-WiFi Vertical Handover Efficiency (LTE-WiFi Vertical 핸드오버 효율향상 방안 연구)

  • Joo, Young-Hwan;Lim, Seung-Cheol
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.17 no.2
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    • pp.127-134
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    • 2017
  • In this paper, we try to solve the frequency shortage due to the increase of LTE terminals and the traffic jam caused by the inefficient WiFi connection method. The proposed LTE-WIFI Vertical Handover method uses a pre-authentication method of the AP through LTE and a method of controlling the access AP of the terminal using the RADIUS server. Through the simulation, the proposed method shows that the access speed of the AP is improved by about 95% compared to the conventional connection method, and the connection speed is improved by about 18% compared to the conventional method. Providing seamless AP through pre-authentication system and improving wireless network speed through AP access distribution can solve LTE frequency shortage problem and improve wireless network usage satisfaction.

A system of several fraction laws for the identification of rotating response of FG shell

  • Yahya, Ahmad;Hussain, Muzamal;Khadimallah, Mohamed A.;Khedher, Khaled Mohamed;Al-Basyouni, K.S.;Ghandourah, Emad;Banoqitah, Essam Mohammed;Alshoaibi, Adil
    • Advances in concrete construction
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    • v.13 no.3
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    • pp.223-231
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    • 2022
  • The problem is formulated by applying the Kirchhoff's conception for shell theory. The longitudinal modal displacement functions are assessed by characteristic beam ones meet clamped-clamped end conditions applied at the shell edges. The fundamental natural frequency of rotating functionally graded cylindrical shells of different parameter versus ratios of length-to-diameter and height-to-diameter for a wide range has been reported and investigated through the study with fractions laws. The frequency first increases and gain maximum value with the increase of circumferential wave mode. By increasing different value of height-to-radius ratio, the resulting backward and forward frequencies increase and frequencies decrease on increasing height-to-radius ratio. Moreover, on increasing the rotating speed, the backward frequencies increases and forward frequencies decreases. The trigonometric frequencies are lower than that of exponential and polynomial frequencies. Stability of a cylindrical shell depends highly on these aspects of material. More the shell material sustains a load due to physical situations, the more the shell is stable. Any predicted fatigue due to burden of vibrations is evaded by estimating their dynamical aspects.

Integrated Design of Feed Drive Systems Using Discrete 2-D.O.F. Controllers (I) - Modeling and Performance Analysis - (이산형 2자유도 제어기를 이용한 이송계의 통합설계 (I) -모델링 및 성능해석-)

  • Kim, Min-Seok;Chung, Sung-Chong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.7
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    • pp.1029-1037
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    • 2004
  • High-speed/precision servomechanisms have been widely used in the manufacturing and semiconductor industries. In order to ensure the required high-speed and high-precision specifications in servomechanisms, an integrated design methodology is required, where the interactions between mechanical and electrical subsystems will have to be considered simultaneously. For the first step of the integrated design process, it is necessary to obtain not only strict mathematical models of separate subsystems but also formulation of an integrated design problem. A two-degree-of-freedom controller described in the discrete-time domain is considered as an electrical subsystem in this paper. An accurate identification process of the mechanical subsystem is conducted to verify the obtained mathematical model. Mechanical and electrical constraints render the integrated design problem accurate. Analysis of the system performance according to design and operating parameters is conducted for better understanding of the dynamic behavior and interactions of the servomechanism. Experiments are performed to verify the validity of the integrated design problem in the x-Y positioning system.