• 제목/요약/키워드: design variable

검색결과 4,368건 처리시간 0.043초

DRM 수신기의 효율적인 수신을 위한 가변 프라임펙터 FFT 설계 (Design Method of Variable Point Prime Factor FFT For DRM Receiver)

  • 김현식;이연성;서정욱;백종호
    • 한국정보통신설비학회:학술대회논문집
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    • 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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    • pp.257-261
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    • 2008
  • The Digital Radio Mondiale (DRM) system is a digital broadcasting standard designed for use in the LF, MF and HF bands of the broadcasting bands below 30 MHz. The system provides both superior audio quality and improved user services / operability compared with existing AM transmissions. In this paper, we propose a variable point Prime Factor FFT design method for Digital Radio Mondiale (DRM) system. Proposed method processes a various size IFFT/FFT of Robustness Mode on DRM standard efficiently by composing Radix-Prime Factor FFT Processing Unit of form similar to Radix-4 by insertion of a variable Prime Factor Twiddle Factor and Garbage data. So, we improved limitation that cannot process 112/176/256/288 FFT of each mode of DRM system with a existent Radix Processor and increase memory size and memory access time for IFFT/FFT processing by software processing in case of implementation with a existent high speed DSP.

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A BANDWIDTH VARIABLE DIGITAL GENERATOR FOR RADAR ALTIMETER

  • Lin, Ying;Liu, Heguang;Liu, Zhiqlang;Xu, Ke;Zhang, Xuabgjyb
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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    • pp.484-489
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    • 2002
  • This paper concerns the design and implementation of a Bandwidth Variable Digital Chirp Generator (DCG) for the radar altimeter. A double SRAM parallel structure is used to breakthrough the upper DCG bandwidth limited by the highest clock frequency of the digital chips. An experimental system working in the waveform storage method has been implemented. We show that the bandwidth changed according to the radar altimeter's requirement and the design released the stringent speed requirement of the chips fur making a variable wide bandwidth DCG.

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ALUMINUM SPACE FRAME B.I.W. OPTIMIZATION CONSIDERING MULTIDISCIPLINARY DESIGN CONSTRAINTS

  • KIM B. J.;KIM M. S.;HEO S. J.
    • International Journal of Automotive Technology
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    • 제6권6호
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    • pp.635-641
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    • 2005
  • This paper presents an ASF (Aluminum Space Frame) BIW (Body in White) optimal design, which minimizes weight and satisfies multidisciplinary constraints such as static stiffness, vibration characteristics, low-/high-speed crash, and occupant safety. As only one cycle CPU time for all the analyses is 12 hours, the ASF design having 11-design variable is a large scaled problem. In this study, ISCD-II and conservative least square fitting method were used for efficient RSM modeling. Likewise, the ALM method was used to solve the approximate optimization problem. The approximate optimum was sequentially added to remodel the RSM. The proposed optimization method uses only 20 analyses to solve the 11-design variable problem. Moreover, the optimal design can achieve $15.6\%$ weight reduction while satisfying all the multidisciplinary design constraints.

이산설계변수를 고려한 복합재 로터블레이드 단면 최적설계 (Optimal Design of Composite Rotor Blade Cross-Section using Discrete Design variable)

  • 원유진;이수용
    • 항공우주시스템공학회지
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    • 제8권1호
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    • pp.12-17
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    • 2014
  • In this paper, optimal design of composite rotor blade cross-section to consider manufacturability was performed. Skin thickness, torsion box thickness and skin lay-up angle were adopted as discrete design variables and The position and width of a torsion box were considered as continuous variables. An object function of optimal design is to minimize the mass of a rotor blade, and various constraints such as failure index, center mass, shear center, natural frequency and blade minimum mass per unit length were adopted. Finally, design variables such as the thickness and lay-up angles of a skin, and the thickness, position and width of a torsion box were determined by using an in-house program developed for the optimal design of rotor blade cross-section.

인체측정자료의 사용성 제고를 위한 인체측정변수 분류 방법 (A Classification Method of Anthropometric Variables for Improved Usability of Anthropometric Data)

  • 유희천;신승우;류태범
    • 대한인간공학회지
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    • 제23권3호
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    • pp.13-24
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    • 2004
  • Anthropometric data is a fundamental resource in developing ergonomic products and workplaces. However, designers often experience difficulty in searching anthropometric data relevant to the design due to the technicality of anthropometric terminologies, ambiguity in the description of measurement method for some anthropometric variables, and inefficiency of existing search methods for anthropometric data. The present study suggests a method to develop a classification system of anthropometric variables for systematic, efficient search of anthropometric data. The proposed method first classifies anthropometric variables according to body segment and type of variable, and then arranges anthropometric variables of the same body segment and variable type by comparing the heights of their reference points. The proposed classification method was applied to establish a classification system of 66 anthropometric variables that were selected for an automotive interior design. Then the established anthropometric classification system was utilized to design a search interface of a web-based anthropometric data retrieval system.

다변수 슬라이딩 모드 제어에 의한 부정합조건 불확실성을 갖는 다입출력 비선형 시스템의 강인그로벌 지수 안정화 (A Robust Global Exponential Stabilization of Uncertain Affine MIMO Nonlinear Systems with Mismatched Uncertainties by Multivariable Sliding Mode Control)

  • 이정훈
    • 전기학회논문지
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    • 제60권9호
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    • pp.1754-1760
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    • 2011
  • In this paper, a systematic design of a robust nonlinear multivariable variable structure controller based on state dependent nonlinear form is presented for the control of MIMO uncertain affine nonlinear systems with mismatched uncertainties and matched disturbance. After a MIMO uncertain affine nonlinear system is represented in the form of state dependent nonlinear system, a systematic design of a robust nonlinear variable structure controller is presented. To be linear in the closed loop resultant dynamics, the linear sliding surface is applied. A corresponding diagonalized control input is proposed to satisfy the closed loop global exponential stability and the existence condition of the sliding mode on the linear sliding surface, which will be investigated in Theorem 1. Through a design example and simulation study, the usefulness of the proposed controller is verified.

발포 폴리스티렌 폼을 이용한 가변 적층 쾌속 조형 공정 설계 및 개발 (Development and Design of Variable Lamination Manufacturing (VLM) Process by Using Expandable Polystyrene Foam)

  • 안동규;이상호;양동열;신보성;박승교;이용일
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2000년도 추계학술대회 논문집
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    • pp.759-762
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    • 2000
  • Rapid Prototyping (RP) techniques have their unique characteristics according to the working principles: stair-stepped surface of parts due to layer-by-layer stacking, low build speed caused by line-by-line solidification to build one layer, and additional post processing to improve surface roughness, so it is required very high cost to introduce and to maintain RP apparatus. The objective of this study is to develop and design a new RP process, Variable Lamination Manufacturing using expandable polystyrene foam sheet as part material (VLM-S), which can make up for the disadvantage of existing techniques, and to develop an apparatus to implement the process. In order to examine the possibility of practical utilization of the proposed VLM-S process for prototyping of a general three-dimensional shape, an auto-shift lever knob and a pyramid shape were fabricated.

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보강재의 수를 포함한 보강판 구조물의 동특성의 최적변경 (The Optimum Modification of Dynamic Characteristics of Stiffened Plate Structure Including the Number of Stiffener)

  • 박성현;고재용
    • 한국항해학회지
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    • 제25권4호
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    • pp.461-469
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    • 2001
  • The purpose of this paper is the optimum modification of dynamic characteristics of stiffened plate structure including the number of stiffener. This paper shows the optimum structural modification method by dynamic sensitivity analysis and quasi-least squares method and considers it's validity. In the method of the optimization, finite element method, sensitivity analysis and optimum structural modification method are used. The change of natural frequency and total weight are made to be an objective function. Thickness of plate, the number of stiffener and cross section moment of stiffener become a design variable. The dynamic characteristics of stiffened plate structure is analyzed using finite element method. Next, rate of change of dynamic characteristics by the change of design variable is calculated using the sensitivity analysis. Then, amount of change of design variable is calculated using optimum structural modification method. It is shown that the results are effective in the optimum modification for dynamic characteristics of the stiffened plate structure including the number of stiffener.

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신경회로망을 이용한 WMR의 가변제어기 설계 (Design of variable controller for WMR using a Neural Network)

  • 김규태;김성회;박종국
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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    • pp.157-160
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    • 2001
  • This paper presents A Design of WMR Controller that being composed of cooperative relation between PID controller and optimized neural network algorithm, it operate a variable control by velocity. Some proposed algorithm in the past just depended on PID controller for the control of position of WMR but for more efficient control we design a variable controller that operate control by PD controller using neural network if it is satisfied with any given condition. it adjust gain of PD controller for real time control using a fast feedforward algorithm which is different with Form of the standard backpropagation algorithm.

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불확실성의 Fredholm 적분 수식화를 통한 적응가변구조제어기 설계 (Design of an Adaptive Variable Structure Control using Fredholm Integral Formulae for the Uncertainties)

  • 유동상
    • 제어로봇시스템학회논문지
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    • 제9권9호
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    • pp.658-663
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    • 2003
  • In deterministic design of feedback controllers for uncertain dynamic systems, the upper bound of the uncertainty is very important to guarantee the stability of the closed loop system. In this paper, we assume that the upper bound of the uncertainty is formulated using a Fredholm integral equation of the first kind, that is, an integral of the product of a predefined kernel with an unknown influence function. We propose an adaptation law that is capable of estimating this upper bound. Using this adaptive upper bound, we design an adaptive variable structure control (AVSC), which guarantees asymptotic stability/ultimate boundedness of uncertain dynamic systems. The illustrative example shows the proposed AVSC is effective for uncertain dynamic systems.