• 제목/요약/키워드: paper disk method

검색결과 611건 처리시간 0.027초

광디스크 드라이브의 디스크 표면 결함에 대한 트래킹 제어 (Track-following Control under Disk Surface Defect of Optical Disk Drive Systems)

  • 정동슬;이준성;정정주
    • 정보저장시스템학회논문집
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    • 제2권1호
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    • pp.56-64
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    • 2006
  • This paper proposes a new and simple input prediction method for robust servo system. A robust tracking control system for optical disk drives to reject disk runout was recently proposed based on both Coprime Factorization(CF) and Zero Phase Error Tracking(ZPET) control. The CF control system can be designed simply and systematically. Moreover, this system has not only stability but also robustness to parameter uncertainties and disturbance rejection capability. Since optical disk tracking servo systems can detect only racking error, it was proposed that the reference input signal for ZPET could be estimated from tracking errors. In this paper, we propose a new control structure for the ZPET controller. It requires less memory than the previously proposed method for the reference signal generation. Therefore, it is very effective in runout control. Furthermore, this method can be applied to defective optical disk like surface defects on disk. Numerical simulation and experimental result show the proposed method effective.

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시뮬레이션 기법을 이용한 완전 비동기 디스크 어레이 성능 평가 (A Performance Evaluation of Fully Asynchronous Disk Array Using Simulation Method)

  • 오유영
    • 한국시뮬레이션학회논문지
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    • 제8권2호
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    • pp.29-43
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    • 1999
  • As real-time processing of data with large storage space is required in the era of multimedia, disk arrays are generally used as storage subsystems which be able to provide improved I/O performance. To design the cost-effective disk array, it is important to develop performance models which evaluate the disk array performance. Both queueing theory and simulation are applicable as the method of performance evaluation through queueing modeling. But there is a limit to the analytical method using queueing theory due to the characteristics of disk array requests being serviced in the parallel and concurrent manner. So in this paper we evaluate the disk array performance using simulation method which abstract disk array systems in the low level. Performance results were evaluated through simulation, so that mean response time, mean queueing delay, mean service time, mean queue length for disk array requests and utilization, throughput for disk array systems, can be utilized for capacity planning in the phase of disk array design.

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유전자 알고리즘을 이용한 다중 디스크 데이터 배치 방식 (Multidisk data allocation method based on genetic algorithm)

  • 안대영;박규호;임기욱
    • 전자공학회논문지C
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    • 제35C권3호
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    • pp.46-58
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    • 1998
  • Multi-disk data allocation problem examined in this paper is to find a method to distribute a Binary Cartesian Product File on multiple disks to maximize parallel disk I/O accesses for partial match retrieval. This problem is known to be NP-hard, and heuristkc approaches have been applied to obtain sub-optimal solutions. Recently, efficient methods have been proposed with a restriction that the number of disks in which files are stored should be power of 2. In this paper, we propose a new disk Allocation method based on Genetic Algorithm(GA) to remove the restriction on the number of disks to be applied. Using the schema theory, we prove that our method can find a near-optimal solutionwith high probability. We compare the quality of solution derived by our method with General Disk Modulo, Binary Disk Modulo, and Error Correcting Code methods through the simulation. The simulation results show that proposed GA is superior to GDM method in all cases and provides comparable performance to the BDM method which has a restriction on the number of disks.

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대규모 VOD서버에서의 DISK I/O SUB SYSTEM의 구현 (Implementation of Disk I/O Sub System in Large Scale Video On Demand Sewer)

  • 선창우;최경희;정기현
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 1999년도 추계종합학술대회 논문집
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    • pp.1053-1056
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    • 1999
  • Video On Demand servers generally require massive disk storages for storing many video data. Many researches have been done on the topics of efficient allocation of movies in disks. This paper, We describe efficient disk placement techniques and implement storage system with SCSI and PCI Bus interface for efficient data handling. This paper also proposes a logical zone reconstruction method for the SCAN data placement technique. The proposed method reconstructs physical zones into logical zones by split and merge operations.

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스트로보스코픽 전자 스페클 패턴 간섭법을 이용한 디스크 브레이크의 진동 모드의 정량적 가시화에 관한 연구 (A Study on Quantitiative visualization of Vibration Mode Shape of Disk Brake by Using Stroboscopic ESPI)

  • 강영준
    • 한국자동차공학회논문집
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    • 제7권9호
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    • pp.97-104
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    • 1999
  • Brake squeal noise has been a problem since the early days of motoring . It is important to obtain vibration mode shape for reduction of brake noise . Stroboscopic Electronic Speckle Pattern Interferometry is a very powerful measuring method for study of vibrating objects in static state compared with conventional methods because this method can give both resonance frequency and quantitative visualization of vibration mode shape at the same time. In this paper, we performed qualitative visualization and quantitative analysis of vibration mode shpae of disk brake by using stroboscopic ESPI and phase shifting method. The stroboscopic wavefronts are obtained by chopping continuous wave laser beam using acousto-optic modulator .Experiments were performed at the same constraint conditions as disk brake of the practical vehicle as far as possible. The experimental results of this paper show quantitative measurement of vibration mode shape and quantiative visualization of vibration amplitude of disk brake with 3D plotting.

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원호접근법을 이용한 디스크 캠기구의 운동해석에 관한 연구 (A Study on the Motion Analysis for Disk Cam Mechanism Using Circular Arc)

  • 구병국;신중호;윤호업;장옥화
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 추계학술대회논문집A
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    • pp.772-777
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    • 2000
  • Cam mechanisms are used commonly in many automatic machinery. Disk cam mechanisms has 4 different types according to the different types of followers. The motion characteristics of the cam mechanisms depend on the shape of the cam and the type of the follower. This paper performs the motion analysis for a disk cam and follower mechanism using a circular arc method and a coordinate transformation method in order to find a contact point of the cam and follower. The velocity is calculated by using the instant velocity concept. Also, the acceleration is determined on using the central difference method. As the results, this paper presents the original curve and the analyzed curve for the motion analysis of the disk cam for an example.

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고속 전철에서 디스크 브레이크의 열거동에 관한 유한요소해석 (Finite Element Analysis of Thermal Behaviours of a Disk Brake in High-Speed Trains)

  • 김청균;조승현
    • Tribology and Lubricants
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    • 제14권1호
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    • pp.28-36
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    • 1998
  • This paper presents the thermal behaviours of a solid type disk brake for a high-speed train. The thermal behaviours of a brake disk with 50mm thickness shows good performance compared with 45mm thickness of a disk because of a high specific heat capacity. The FEM results show that the thickness of the disk with a same weight of the brake disk should be increased for a good flexibility of the contact thermal problems. Therefore, the ratio between the pad and disk in diameter may be reduced and the thickness of a disk increased.

요동운동 롤러 종동절과 디스크 캠 기구의 운동해석을 위한 원호 접근법에 관한 연구 (A Study on circular Arc Approach for Motion Analysis of Oscillating Roller Follower and Disk Cam Mechanisms)

  • 구병국;신중호;윤호업;장옥화
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2000년도 추계학술대회 논문집
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    • pp.523-526
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    • 2000
  • This paper performs the motion analysis for a disk cam and a follower mechanism using a circular arc method, a coordinate transformation method and an instant velocity method in order to find a contact point between the cam and the follower. Based on the proposed method, the displacement and the velocity are calculated by using the geometric relationships of the cam mechanism. Also, the acceleration is determined on using the central difference method. As the results, this paper presents the original curve and the analyzed curve for the motion analysis of the disk cam for an example.

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Bi-arc법을 이용한 평면 캠의 정밀 가공 기술에 관한 연구 (A Study on Precision Machining Technology for Disk Cams using Bi-arc Method)

  • 신중호;권순만;조인영;김종찬;강한성
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2006년도 춘계학술대회 논문집
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    • pp.235-236
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    • 2006
  • The disk cam mechanism can produce a positive motion with relatively few components. This paper introduce a shape design of cam using the relative velocity method and a precision machining technology for using Bi-arc method. The paper gives a machining information at each point using the Bi-arc method and the analysis method of the cutting error due to the moving path of the cutter, so that we can lead to the optimum design in a disk cam mechanism.

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광디스크 드라이브의 디스크 표면 결함에 대한 트래킹 제어 (Track-following Control for Disk Surface Defect of Optical Disk Drive Systems.)

  • 이준성;정동슬;정정주
    • 정보저장시스템학회:학술대회논문집
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    • 정보저장시스템학회 2005년도 추계학술대회 논문집
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    • pp.223-228
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    • 2005
  • In oprical disk drives, surface defects on a disk distort tracking error signal and disturb a precision tracking control.. A conventional method against disk defect is held the tracking control signal when a defective portion is detected. However, if the defective portion is getting longer, objective lens will get away from following track. In order to keep the postion of spot from following track, the servo system must predict tracking error and control the object lens in the defective portion. A tracking control system for optical disk drives was proposed recently based on both Coprime Factorization(CF) and Zero Phase Erro. Tracking(ZPET) control. The system was proposed for overcome the limit of previously tracking error. But there were no research about the method against the defective portion. This paper proposes a new and simple ZPET construct. as a new method against the defective portion. From experimental results, we have proved that proposed method improves the performance against the defective portion, decreases the uncertainty of a model, and requires less memory than the previously proposed method.

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