• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1997년도 학술대회
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• pp.181-186
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• 1997

Transcoding is the key technique to further reduce the bit-rate of a previously compressed video. The performance of the transcoding is evaluated by the two factors, the accuracy on the target bit-rate and the complexity of the implementation. In this paper, were propose a new rate control algorithm which has very accurate bit-rate control performance and much smaller computational complexity. For the accuracy problem, we empirically observe the relationship between the quantization step size and generated bits in requantization process and then find that the relationship can be characterized as the new piece-wise linear model. For the complexity problem, we reduce the role of feedback rate control. The simulation results show that the proposed method gives the better performance in the accuracy with the same picture quality than conventional rat control algorithm.

• 한국생산제조학회지
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• 제9권6호
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• pp.164-169
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• 2000

Recently, High accuracy and precision are required in various industrial field especially, semiconductor manufacturing apparatus, Ultra precision positioning apparatus, Information field and so on. Positioning technology is a very important one among them. As such technology has been rapidly developed, this field needs the positioning accuracy as high as submicron. It is expected that the accuracy of 10nm and 1nm is required in precision work and ultra precision work field, respectively by the beginning of 2000s. High speed and low vibration are also needed. This work deals with the design method and control system of Ultra precision positioning apparatus. Control performance and stability analysis were performed in advance by modeling and designing the controller with Simulink.

• 한국측량학회지
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• 제30권5호
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• pp.445-458
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• 2012

GPS 기준점 측량은 관측과 데이터 처리를 통해 측지계에 대한 물리적인 표지의 위치를 목표 정확도 범위 이내로 결정하기 위해 실시하며, 이러한 이유로 측량 정확도를 실제와 유사하게 표현하는 것이 매우 중요한 문제이다. 망조정을 통해 산정되는 기준점 성과의 정확도는 사용되는 수학적 모형에 민감한 영향을 받는 추정좌표의 분산-공분산 행렬에 의해 정량적으로 표현된다. 본 연구는 GPS 망조정에 사용되는 함수모형과 통계모형이 기준점 위치 추정과 정확도 표현에 미치는 영향을 연구하여 향후 정확도 표현의 표준화를 위한 기초자료 확보를 위해 실시하였다. 이를 위하여 단일기선해석 다중세션 망조정 이론과 절차와 방법을 실제 관측데이터 처리를 통한 수치적 분석을 병행한 연구를 수행 하였다. 그 결과 절대정확도와 상대정확도를 보다 현실적으로 반영하여 표현하기 위해서는 잔존하는 관측오차의 모형화가 가능한 경험적 통계모형을 사용하는 다점가중제약조정이 GPS 기준점 성과산정을 위한 수학적 모형으로 보다 타당한 것으로 분석되었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2382-2386
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• 2003

The Global Positioning System(GPS) is a satellite based precise positioning system avaliable worldwide. The GPS have many error sources. The earth's ionosphere and atmosphere cause delays in the GPS signal that translate into position errors. Some errors can be factored out using mathematics and modeling. The configuration of the satellites in the sky can magnify other errors. The problem of accuracy on GPS measurement data can be meaningful. In this study, we propose the method for GPS positioning accuracy improvement. The FUZZY set theory on PDOP(Position Dilution of Precision) and SNR(Signal to Noise Ratio) provide improved for measured positioning data. The accuracy of positioning has been improved by selecting data from original using the FUZZY set theory on PDOP and SNR.

• 대한방사선기술학회지:방사선기술과학
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• 제42권1호
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• pp.31-37
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• 2019

Investigate the adequacy awareness of accuracy control of CT apparatus Questionnaire survey and statistical analysis in the analysis according to age, there is a difference between familiarity with accuracy management items (F = 14.187, p<0.001) and necessity of accuracy control (F=8.109, p<0.001), depending on academic background and work history, There is a difference only in familiarity (F=5.103, p<0.05, F=13.394, p<0.001), and according to the scale of the medical institution analysis shows that if you are more interested than senior general hospital grade hospital grade or less It was analyzed. In order to advance the accuracy control level, we have introduced our comprehensive and efficient comprehensive and efficient integrated medical image quality management operation system of the whole medical image equipment including CT device, It is thought that it is necessary to develop human resources capable of doing.

• 항공우주시스템공학회지
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• 제15권3호
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• pp.57-64
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• 2021

본 연구에서는 KV의 유도조종오차를 최소화하여 직격요격 성능을 확보하고자 DACS 구동장치에 대한 위치정확도 점검방안을 제안하였다. DACS 구동장치의 정확도 성능은 탄도미사일 요격에 중요한 성능 중 하나이다. DACS 구동장치의 정확도 성능을 검증하기 위해 위치정확도란 점검 항목을 도출하였고, 이에 대한 점검시스템 설계 및 점검절차를 기술하였다. 핀틀 위치정확도 점검시스템은 레이저 변위센서를 이용하여 핀틀의 구동변위를 외부 계측할 수 있도록 구성하였고, 외부 계측한 데이터는 실시간으로 구동명령 및 피드백 데이터와 비교분석할 수 있도록 설계하였다. 본 논문에서 제안하는 위치정확도 점검시스템은 DACS 조립체 뿐만 아니라 유도탄 조립체 단위에서도 점검이 가능하도록 설계하였다. 설계된 점검시스템을 이용하여 핀틀의 위치정확도 점검을 수행하였고, 점검 결과를 분석하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.969-972
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• 2004

This paper describes the mechanism of parallel micro machine platform and its feedback control system for acquiring high accuracy. The parallel micro machine platform that has developed has 5x5x5 work-space and sub-micron accuracy. For the high accuracy, the feedback control system is important but errors in machining and assembling are inevitable. Kinematic calibration is important for this reason. In this paper, various error components are introduced and the effects of error component are analyzed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집(한일합동학술편); 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.759-764
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• 1987

The design and application of optimal control technique to the rotary shearing system is mentioned in this paper. To maximize the accuracy in both shearing length and blade speed at shearing, time-varying gain patterns for closed loop control are designed on the basis of fixed terminal time constrained optimal regulator. The performance accuracy in real application has greatly improved than the conventional way of shearing control.

• 제어로봇시스템학회논문지
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• 제20권2호
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• pp.175-179
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• 2014

The histogram specification turns the shape of a histogram into that we want to specify. This technique can be applied usefully in various image processing fields such as machine vision. However, the histogram specification technique has its basic limits. For instance, the histogram does not have location information of pixels. Also, the accuracy of the specification drops because of quantization errors of the digitized image. In this paper, we proposed a multiresolution histogram specification method in order to improve the accuracy of specification in terms of resemblance between destination and source image. The experimental results show that the proposed method enhances the accuracy of the specification compared to the conventional methods.

• 제어로봇시스템학회논문지
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• 제5권1호
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• pp.88-94
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• 1999

This paper presents an accuracy evaluation method for muzzle velocity measurement systems. Among various measuring techniques, the solenoid coil scheme and the doppler radar scheme are considered due to their popularity in applications. The error sources are first identified and their effects on the accuracy of the measuring systems are quantified using mathmatical equations. The theoritic accuracy limits are then verified through comparison with experimental results. From the accuracy point of view, they turn out to be standard velocity measuring systems.