A Sampling Inspection Plan with Human Error

Yong-Hwa Lee,Seung-Kweon Hong 대한인간공학회 2011 大韓人間工學會誌 Vol.30 No.5

Objective: The aim of this study is to design a sampling inspection plan with human error which is changing according to inspection time. Background: Typical sampling inspection plans have been established typically based on an assumption of the perfect inspection without human error. However, most of all inspection tasks include human errors in the process of inspection. Therefore, a sampling inspection plan should be designed with consideration of imperfect inspection. Method: A model for single sampling inspection plans were proposed for the cases that visual inspection error rate is changing according to inspection time. Additionally, a sampling inspection plan for an optimal inspection time was proposed. In order to show an applied example of the proposed model, an experiment for visual inspection task was performed and the inspection error rates were measured according to the inspection time. Results: Inspection error rates changed according to inspection time. The inspection error rate could be reflected on the single sampling inspection plans for attribute. In particular, inspection error rate in an optimal inspection time may be used for a reasonable single sampling plan in a practical view. Conclusion: Human error rate in inspection tasks should be reflected on typical single sampling inspection plans. A sampling inspection plan with consideration of human error requires more sampling number than a typical sampling plan with perfect inspection. Application: The result of this research may help to determine more practical sampling inspection plan rather than typical one.

다채널 TI-ADC를 위한 샘플 시간 불일치 보정 기법

라동준,서원기,심홍석,최권휴 한국통신학회 2022 韓國通信學會論文誌 Vol.47 No.5

Sample timing mismatch between analog-to-digital converters (ADC) channels is a major factor in degrading the spurious free dynamic range (SFDR) performance of Time-interleaved ADCs (TI-ADCs). In the conventional sample timing mismatch calibration scheme for multi-channel TI-ADC, an approximated frequency response was applied to the calibration filters, because the frequency response is induced in a complicated closed-form expressions. Thus, SFDR performance improvements are reduced by approximation in environments with large sample timing mismatch. In this paper, we propose a sample timing mismatch calibration scheme robust to sample timing mismatch for multi-channel TI-ADC. In order to calibrate the sample timing mismatches between multiple channels, all channels are paired into groups, and the mismatch is calibrated for each group. Then, grouping and calibration are sequentially performed on the results of the previous calibration to calibrate the sample timing mismatch of all channels. The performance simulations show that the proposed scheme maintains the calibration performance even in an environment in which the sample timing mismatch range is large, whereas the conventional scheme degrades the calibration performance as the sample timing mismatch range increases. 아날로그-디지털 변환기 (ADC) 채널간 샘플 시간 불일치는 Time-interleaved ADC (TI-ADC)의 Spurious Free Dynamic Range (SFDR) 성능을 저하시키는 주요 요인이다. 기존의 다채널 TI-ADC의 샘플 시간 불일치 보정 기법에서는 보정필터의 주파수 응답이 매우 복잡한 식으로 유도되므로 근사화된 주파수 응답을 적용하였고, 근사화에 의해 샘플 시간 불일치 값의 범위가 큰 환경에서는 SFDR 성능 개선량이 감소한다. 본 논문에서는, 다채널TI-ADC를 위한 샘플 시간 불일치에 강인한 샘플 시간 불일치 보정 기법을 제안한다. 제안하는 기법은 여러 채널의 샘플 시간 불일치를 보정하기 위해, 모든 채널을 2개 채널씩 그룹으로 묶고, 그룹별로 불일치를 보정한다. 그다음, 이전 보정의 결과에 대해 그룹화 및 보정을 순차적으로 수행하여 최종적으로 모든 채널의 샘플 시간 불일치를 보정한다. 성능 실험 결과에서, 기존 기법은 샘플 시간 불일치 범위가 증가함에 따라 보정 성능이 저하되지만, 제안하는 기법은 샘플 시간 불일치 범위가 큰 환경에서도 보정 성능이 유지되는 것을 확인할 수 있다.

New and Improved Time-selective Self-triggering Water Sampler: AUTTLE

Jin, Jae-Youll,Hwang, Kuen-Choon,Park, Jin-Soon,Eo, Young-Sang,Kim, Seong-Eun,Yum, Ki-Dai,Oh, Jae-Kyung Korea Institute of Ocean Science Technology 2000 Ocean and Polar Research Vol.22 No.2

Time-selective self-triggering water sampler, AUTTLE developed by Jin et al. (1999) has been improved in order to prevent pre-deposition of suspended sediments (SS) before sampling. By using two solenoids, the improved sampler is able to be moored or deployed with inclination. Its position is changed to horizontal position by activating the first solenoid, and then the endcaps of the sampling bottle are closed by the second solenoid that is driven three times to minimize possible failure of sampling. An external control unit for setting sampling time has been also constructed. Additionally, the electric circuit housing of the sampler has been modified to be detached from the sampling bottle when operating manually. Its performance has been confirmed through flume tests and a field experiment. It will serve as a valuable tool in the various fields of oceanography and environmental engineering, especially where seawater sampling synchronized at several sites and/or the information in storm period is important.

모바일 로봇 모션 제어에 있어 샘플링 시간의 효과

장태호(Tae ho Jang),김영식(Young shik Kim) 한국산업경영시스템학회 2014 한국산업경영시스템학회지 Vol.37 No.4

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.

풍파랑 하중 샘플링 개수에 따른 플로팅 건물의 시간이력 응답 특성

이영욱,박태준 대한건축학회지회연합회 2016 대한건축학회연합논문집 Vol.18 No.1

플로팅 건물의 시간이력 해석을 위하여 필요한 최소한의 입력하중의 개수를 확인하기 위하여, 100개의 불규칙 풍파랑 하중에 대한 동수역학 해석을 수행하여 좌우동요와 횡동요를 고찰하고, 이 100개의 결과 중에서 30개를 건물의 밑면에 작용하는 입력하중으로 사용하여 부분골조 해석을 수행하였다. 30개의 해석결과 중 7와 15개의 샘플을 추출하여 평균과 표준편차를 비교하였다. 7개의 샘플링에 의한 지붕층의 변위값이나 가속도 및 모멘트의 값은 30개의 샘플의 평균값의 5% 이내의 오차가 발생하였으므로, 불규칙하중에 대한 해석 및 설계시 7개의 풍파랑 불규칙 하중에 대한 상부구조물의 평균값을 사용할 수 있음을 시사하였다. 그러나 표준편차의 경우는 샘플링의 개수에 따라 편차가 크게 발생하였으므로 확률적인 분포를 고려한 평가에서는 7개 하중의 평균값은 신뢰성이 떨어질 것으로 판단된다. 라틴하이퍼큐브에 의한 7개의 샘플링의 평균치와 표준편차는 30개 샘플링의 값과 근사하여, 상부구조물의 설계 및 확률분포의 추정시 안정적인 방법으로 사용될 수 있을 것임을 시사하였다. To study the effective sampling number of wind and wave loading on a floating building, 30 rolling and sway accelerations are selected from 100 hydrodynamic analysis samples, to find the historical response of the acceleration and displacement and the moment of beam and column of the building frame using substructure analysis. From 30 results, 7 and 15 are randomly sampled and the response of them are compared with that of 30 sampling. The average value of 7 random sampling shows good correspondence with the 30 sampling value but the standard deviation of 7 sampling is different from that of 30 sampling. But in case of 7 Latin Hypercube sampling, it shows good correspondence with 30 sampling result.

Changes of the Blood Composition of Periparturient Cows in Relation to Time of Day

Toharmat, T.,Nonaka, I.,Shimizu, M.,Kume, S. Asian Australasian Association of Animal Productio 1999 Animal Bioscience Vol.12 No.7

In order to determine the appropriate sampling time for blood metabolites of periparturient cows, the changes of the blood composition in relation to time of day were evaluated in sixteen multiparous Holstein cows at 1 wk prepartum, 1 and 6 d postpartum. Blood samples were collected at 08:30, 10:00, 15:30 and 17:00 h in each sampling day, and the sampling times at 08:30 and 15:30 h were prior to feeding. The rectal temperature of cows increased gradually from 08:30, to 17:00 h, but blood Hct and Hb decreased constantly. Plasma non-esterified fatty acid (NEFA) concentration at 08:30 h was two-fold higher than those at 10:00, 15:30 and 17:00 h from 1 wk prepartum to 6 d postpartum, and the value was maximum at 1 d postpartum. The highest plasma urea-N was observed at 10:00 h from 1 wk prepartum to 6 d postpartum. Plasma glucose and total protein were not affected by sampling time. The data indicated that blood samples of periparturient cows should be collected before morning feeding for the diagnosis of energy status, because plasma NEFA was the highest before morning feeding.

Stability analysis of time-varying sampling systems with scheduling dependent probabilistic bound information

Young Soo Suh 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

This paper is concerned with a networked control system whose sampling time is time-varying. It is assumed that probabilisitic information of the sampling time variation is known. By explicitly using the probabilistic information, a less conservatives tability condition is derived. The stability condition is based on stability conditions of Markov jump linear systems. Through a simulation, it is shown that the proposed method is less conservative than existing stability conditions.

Quantifying the Quality and Sampling Time of Oil and Grease in Urban Stormwater Runoff

M. F. Chow,Z. Yusop 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.4

Oil and Grease (O&G) pollution in urban stormwater runoff is an important issue especially for tropical country with high intense and frequent storms. Monitoring of O&G pollution is comparably more difficult than other conventional constituents due to the requirement of manual grab sampling technique. Thus, this paper was aimed to investigate the O&G quality and quantify an appropriate sampling time for collecting sample that approximating Event Mean Concentration (EMC) of O&G (EMCO&G) from residential, commercial and industrial catchments. An average of 16 storm events was collected from each land use in order to assess the quality of O&G in stormwater runoff. A series of stormwater samples were manually grabbed by sampling personnel along with the storm flow measurements. Results showed that industrial catchment always exhibited the highest EMCO&G value, followed by commercial and residential catchments. Correlation analysis indicated that EMCO&G was correlated well with EMCs of NO3-N, NH3- N, TP and SP in the commercial catchment. The EMCO&G was also found to be independent of all storm characteristics, except for storm duration in the industrial catchment. Results obtained from this study suggested that the mean sampling times for collecting EMCO&G sample (TEMCO&G) at residential, commercial and industrial catchments are 17, 17 and 20 minutes, respectively. The TEMCO&G had mostly preceded the peak flow by a time-based ratio of 0.70. Thus, this best time sampling strategy can be implemented based on forecasting rainfall and estimated time to peak flow at catchment outlet.

청소년의 건강행태요인이 인터넷 사용시간에 미치는 영향

안성윤,서은주 한국엔터테인먼트산업학회 2022 한국엔터테인먼트산업학회논문지 Vol.16 No.7

This study was carried out to identify factors affecting the Internet use time according to the weekly schedule of adolescents and to establish a preventive strategy for guiding the Internet use of adolescents. The data were obtained from the 15th Korea Youth Risk Behavior Survey(KYRBS) 2019, and complex-sample frequency analysis and linear regression analysis were performed using the SPSS program. As a result of the study, the factors affecting internet usage time during the week were subjective body image, breakfast frequency in the last 7 days, days of high-intensity physical activity in the last 7 days, days of high-intensity physical activity in the last 7 days, and days of strength training in the last 7 days, stress, degree of fatigue recovery from sleep in the last 7 days, walking time on days of walking for more than 10 minutes in the last 7 days, sleeping time in the last 7 days, and time spent sitting in the last 7 days, the explanatory power was 14.8% (F = 77.984, p<.05). Factors that affect weekend internet usage time include subjective health, subjective body image, frequency of breakfast in the past 7 days, days of high-intensity physical activity in the past 7 days, stress, degree of fatigue recovery from sleep in the past 7 days, and walking time on days of walking for more than 10 minutes, sleeping time for the last 7 days, and time spent sitting for the last 7 days, the explanatory power was 21.8% (F=158.720, p<.05). Based on this, it is expected that effective prevention strategies can be established for guiding adolescents' Internet use time.

Sampled-data observer-based output-feedback fuzzy stabilization of nonlinear systems: Exact discrete-time design approach

Kim, D.W.,Lee, H.J. North-Holland 2012 Fuzzy Sets and Systems Vol. No.

This paper presents a new direct discrete-time design methodology of a sampled-data observer-based output-feedback fuzzy controller for a class of nonlinear system that is exactly modeled in Takagi-Sugeno's form at least locally. A fundamental yet challenging issue in this direction is the unavailability of the exact discrete-time model of the nonlinear plant in a closed form. In contrast to the earlier works that are based on an approximate discrete-time model thus the stability obtained in the design step is not preserved in the implementation step, we employ an exact discrete-time fuzzy model in an integral form. Sufficient asymptotic stabilization conditions are investigated in the discrete-time Lyapunov sense. We then show that the resulting sampled-data controller indeed asymptotically stabilizes the nonlinear plant. An example is provided to illustrate the effectiveness of the proposed methodology.