• 제목/요약/키워드: Sampling Range

검색결과 918건 처리시간 0.025초

모바일 로봇 모션 제어에 있어 샘플링 시간의 효과 (Effects of the Sampling Time in Motion Controller Implementation for Mobile Robots)

  • 장태호;김영식
    • 산업경영시스템학회지
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    • 제37권4호
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    • pp.154-161
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    • 2014
  • In this research we investigate motion controller performance for mobile robots according to changes in the control loop sampling time. As a result, we suggest a proper range of the sample time, which can minimize final posture errors while improving tracking capability of the controller. For controller implementation into real mobile robots, we use a smooth and continuous motion controller, which can respect robot's path curvature limitation. We examine motion control performance in experimental tests while changing the control loop sampling time. Toward this goal, we compare and analyze experimental results using two different mobile robot platforms; one with real-time control and powerful hardware capability and the other with non-real-time control and limited hardware capability.

2단 크리깅 메타모델과 유전자 알고리즘을 이용한 신뢰도 계산 (Reliability Estimation Using Two-Staged Kriging Metamodel and Genetic Algorithm)

  • 조태민;주병현;정도현;이병채
    • 대한기계학회논문집A
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    • 제30권9호
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    • pp.1116-1123
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    • 2006
  • In this study, the effective method for reliability estimation is proposed using tow-staged kriging metamodel and genetic algorithm. Kriging metamodel can be determined by appropriate sampling range and the number of sampling points. The first kriging metamodel is made based on the proposed sampling points. The advanced f'=rst order reliability method is applied to the first kriging metamodel to determine the reliability and most probable failure point(MPFP) approximately. Then, the second kriging metamodel is constructed using additional sampling points near the MPFP. These points are selected using genetic algorithm that have the maximum mean squared error. The Monte-Carlo simulation is applied to the second kriging metamodel to estimate the reliability. The proposed method is applied to numerical examples and the results are almost equal to the reference reliability.

샘플링 기법에 의한 작업순서의 결정 (II) (A Study on Determining Job Sequence by Sampling Method (II))

  • 강성수;노인규
    • 산업경영시스템학회지
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    • 제12권19호
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    • pp.25-30
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    • 1989
  • This study is concerned with a job sequencing method using the concept of sampling technique. This sampling technique has never been applied to develop the scheduling algorithms. The most job sequencing algorithms have been developed to determine the best or good solution under the special conditions. Thus, it is not only very difficult, but also taken too much time to develop the appropriate job schedules that satisfy the complex work conditions. The application areas of these algorithms are also very narrow. Under these circumstances it is very desirable to develop a simple job sequencing method which can produce the good solution with the short tine period under any complex work conditions. It is called a sampling job sequencing method in this study. This study is to examine the selection of the good job sequence of 1%-5% upper group by the sampling method. The result shows that there is the set of 0.5%-5% job sequence group which has to same amount of performance measure with the optimal job sequence in the case of experiment of 2/n/F/F max. This indicates that the sampling job sequencing method is a useful job sequencing method to find the optimal or good job sequence with a little effort and time consuming. The results of ANOVA show that the two factors, number of jobs and the range of processing time are the significant factors for determining the job sequence at $\alpha$=0.01. This study is extended to 3 machines to machines job shop problems further.

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우리나라 당뇨병의 역학적 규모와 당뇨병 관리현황 파악을 위한 표본설계의 평가 (An Evaluation of Sampling Design for Estimating an Epidemiologic Volume of Diabetes and for Assessing Present Status of Its Control in Korea)

  • 이지성;김재용;백세현;박이병;이준영
    • Journal of Preventive Medicine and Public Health
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    • 제42권2호
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    • pp.135-142
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    • 2009
  • Objectives : An appropriate sampling strategy for estimating an epidemiologic volume of diabetes has been evaluated through a simulation. Methods : We analyzed about 250 million medical insurance claims data submitted to the Health Insurance Review & Assessment Service with diabetes as principal or subsequent diagnoses, more than or equal to once per year, in 2003. The database was re-constructed to a 'patient-hospital profile' that had 3,676,164 cases, and then to a 'patient profile' that consisted of 2,412,082 observations. The patient profile data was then used to test the validity of a proposed sampling frame and methods of sampling to develop diabetic-related epidemiologic indices. Results : Simulation study showed that a use of a stratified two-stage cluster sampling design with a total sample size of 4,000 will provide an estimate of 57.04%(95% prediction range, 49.83 - 64.24%) for a treatment prescription rate of diabetes. The proposed sampling design consists, at first, stratifying the area of the nation into "metropolitan/city/county" and the types of hospital into "tertiary/secondary/primary/clinic" with a proportion of 5:10:10:75. Hospitals were then randomly selected within the strata as a primary sampling unit, followed by a random selection of patients within the hospitals as a secondly sampling unit. The difference between the estimate and the parameter value was projected to be less than 0.3%. Conclusions : The sampling scheme proposed will be applied to a subsequent nationwide field survey not only for estimating the epidemiologic volume of diabetes but also for assessing the present status of nationwide diabetes control.

지리산 왕등재 습지의 지표수 수질 및 토양 환경조사 (A Study on Characteristics of Surface Water and Soil in Wangdungjae Wetland Located at Chiri-Mountain)

  • 김종오;이창호;지인주
    • 한국습지학회지
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    • 제3권1호
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    • pp.61-73
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    • 2001
  • This study was performed to survey the characteristics of surface water and soil in Wangdungjae wetland located at Chiri-Mountain. The results of survey summarized as follows; 1. The physico-chemical characteristics of surface water such as pH, temperature, and DO were in the range of 6.02-6.39, $13.5-24.3^{\circ}C$ and 3.81-9.97 mg/L, respectively. Also, the organic concentrations such as BOD and COD were in the range of 1.3-1.61 mg/L and 3.55-9.97 mg/L, respectively. The water quality of five different sampling sites showed the similar characteristics. 2. The physico- chemical characteristics of soil showed the different properties with the soil sampling depth. According to increasing sampling depth, cation exchange capacity (CEC) and electric conductivity (EC) increased but pH decreased. 3. The future survey and researches on surface water and soil environments are needed to preserve the Wangdungjae wetland at Chiri-mountain marsh.

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적외선 신호 해석을 위한 해양 기상 표본 추출법 (A New Sampling Method of Marine Climatic Data for Infrared Signature Analysis)

  • 김윤식
    • 대한조선학회논문집
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    • 제51권3호
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    • pp.193-202
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    • 2014
  • This paper presents a new method of sampling the climatic data for infrared signature analysis. Historical hourly data from a stationary marine buoy of KMA(Korean Meteorological Administration) are used to select a small number of sample points (N=100) to adequately cover the range of statistics(PDF, CDF) displayed by the original data set (S=56,670). The method uses a coarse bin to subdivide the variable space ($3^5$=243 bins) to make sample points cover the original data range, and a single-point ranking system to select individual points so that uniform coverage (1/N = 0.01) is obtained for each variable. The principal component analysis is used to calculate a joint probability of the coupled climatic variables. The selected sample data show good agreement to the original data set in statistical distribution and they will be used for statistical analysis of infrared signature and susceptibility of naval ships.

최적화된 샘플링 인수를 갖는 단일 채널 RF 샘플링 방식의 다중점 펄스 도플러 시스템을 사용한 혈류 속도분포 측정 (Volumetric Blood Velocity Measurement on Multigate Pulsed Doppler System based on the Single Channel RF Sampling using the Optimized Sampling Factor)

  • 임춘성;민경선
    • 대한의용생체공학회:의공학회지
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    • 제19권2호
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    • pp.143-152
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    • 1998
  • In this paper, we present the performances of a Doppler system using single channel RF(Radio Frequency) sampling. This technique consists of undersampling the ultrasonic blood backscattered RF signal on a single channel. Conventional undersampling method in Doppler imaging system have to use a minimum of two identical parallel demodulation channels to reconstruct the multigate analytic Doppler signal. However, this system suffers from hardware complexity and problem of unbalance(gain and phase) between the channels. In order to reduce these problems, we have realized a multigate pulsed Doppler system using undersampling on a single channel, It requires sampling frequency at $4f_o$(where $f_o$ is the center frequency of the transducer) and 12bits A/D converter. The proposed " single-Channel RF Sampling" method aims to decrease the required sampling frequency proportionally to $4f_o$/(2k+1). To show the influence of the factor k on the measurements, we have compared the velocity profiles obtained in vitro and in vivo for different intersequence delays time (k=0 to 10). We have used a 4MHz center frequency transducer and a Phantom Doppler system with a laminar stationary flow. The axial and volumetric velocity profiles in the vessel have been computed according to factor k and have been compared. The influence of the angle between the ultrasonic beam and the flow axis direction, and the fluid viscosity on the velocity profiles obtained for different values of k factor is presented. For experiment in vivo on the carotid, we have used a data acquisition system with a sampling frequency of 20MHz and a dynamic range of 12bits. We have compared the axial velocity profiles in systole and diastole phase obtained for single channel RF sampling factor.ng factor.

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자기 공명 영상 데이터의 oversampling을 통한 quantization noise 개선

  • 김휴정;안창범
    • 대한자기공명의과학회:학술대회논문집
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    • 대한자기공명의과학회 2002년도 제7차 학술대회 초록집
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    • pp.96-96
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    • 2002
  • 목적: MRI 시스템의 비약적인 발전으로 인하여, 시스템에서 발생되는 noise가 상당히 줄었다. 따라서 시스템에서 발생되는 random noise뿐만 아니라 sampling 과정에서 발생되는 quantization noise도 중요하게 고려하여야 할 요소가 되었다. 특히, MRI 신호의 경우 dynamic range가 크기 때문에 bit 수가 큰 ADC를 이용하여 데이터를 얻어야 한다. 그러나, bit 수가 크고 높은 sampling rate를 갖는 ADC의 경우 가격이 높을 뿐만 아니라, 기존의 장비를 교체해야하는 어려움이 있다. 본 연구는 oversampling과 quantization noise와의 관계를 컴퓨터 시뮬레이션을 통하여 알아보고, MRI영상에서 oversampling을 통하여 quantization noise를 줄임으로써 영상의 질을 개선하고자 한다.

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변량표본추출간격을 이용한 범위관리도와 분산관리도의 ATS비교 (A Comparison of Average Time Rate with range and variance chart when using variable sampling interval)

  • 이희춘;지선수
    • 산업경영시스템학회지
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    • 제17권30호
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    • pp.101-106
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    • 1994
  • The basic of the VSI charts is that if the sample statistic computed after a sample is taken shows some indication of a process change than the sampling interval before the next sample should be short otherwise long. This paper was shown the VSS chart can be considerably more efficient than the FSS chart and the effectiveness of VSI R chart with S chart used for monitoring a process standard deviation.

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선별형 2회 샘플링 검사방식의 최적설계를 위한 알고리즘 개발 (An Algorithm for Determining Double Rectifying Inspection Plans)

  • 강보철;조재립
    • 품질경영학회지
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    • 제24권4호
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    • pp.207-223
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    • 1996
  • These days, customers have attached great importance to the function of product liability and quality assurance. In Korea, the single rectifying sampling inspection for attribute (KS A 3105) has been used. But this inspection plan given by tables (KS A 3105) has some defects. There are limitations in the range of applications and irrationality of approximate probability and the double rectifying sampling inspection is not mentioned. Moreover, ATI (average total inspection) does not reflect sampling costs and the loss of nonconforming item. Therefore, the objectives of this study is to develope new algorithms and computer program that provide the optimal sampling inspection plan based on minimum linear costs (single & double inspection plan). The result of this study revealed that the new algorithm is less than KS A 3105 in ATI and basically, double inspection plan is more economical. Also it comes over restrictions in KS A 3105. So, it is definite that the optimal solution can be obtained considering cost factors in manufacturing and sampling process, and costs can be saved in the long term.

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