Yang Xianhui
Tsinghua University
EngineeringReliability engineeringPartial least squares regressionSafety instrumented systemComputer science
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Publications 12
Jul 1, 2008 in CCC (Chinese Control Conference)
#1Zhang Bin (THU: Tsinghua University)H-Index: 1
#2Yang Xianhui (THU: Tsinghua University)H-Index: 2
Last. Kang RongxueH-Index: 1
view all 3 authors...
When evaluating safety integrity level of safety instrumented system, uncertainties are often brought into the analysis and will work on the result. This article explains where uncertainties come from and mainly discuss the problem of common cause failure. Based on the simple beta factor model referred in IEC61508, we introduce an advanced Improved Beta Factor Model to reduce the uncertainty of the safety index PFDavg better. The result from calculating common cause failure or not is compared, a...
1 CitationsSource
#1Yang Xianhui (THU: Tsinghua University)H-Index: 2
The average probability of failure on demand is the main basis used to determine the safety integrity level of safety instrumented systems.This paper presents a discrete Markov model for analyzing the PFD_(avg).Eigenvalue decomposion is used to improve the efficiency and accuracy.This technique is used to relate the system states transition rate and the eigenvalues.This relation describes the changes in PFD_(avg) with time and the key reasons controlling the system.
1 Citations
#1Yang Xianhui (THU: Tsinghua University)H-Index: 2
A three-sided measurement method,a weighted least squares estimation method and a robust least squares estimation method are used to make wireless sensor network node localization more accurate.The three-sided measurement method and the least squares estimation method based on the three-sided method are improved for a specific set of assumptions.A robust least squares estimation method is used to improve node localization.Simulations show that these methods reduce the localization error.The robu...
5 Citations
To decrease the influence of parameter uncertainty on safety integrity level evaluation result of safety instrumented system and to prevent large deviation caused by the lack of data,this paper,taking typical redundant structure as an example,introduces the Monte-Carlo numerical emulation method to calculate average probability of failure on demand,and makes a statistical analysis of the results with Matlab simulation.Comparison with common evaluation methods shows that using interval to describ...
#1Yang Xianhui (THU: Tsinghua University)H-Index: 2
A Markov analysis technique was used to calculate reliability measures for safety systems that involve several typical reliability related factors. The calculations in the Markov model are reduced by prior iterative multiplications of the state transition matrix and the best iterative point. The results show that the probability of failure on demand increases as the number of iterations increases. Errors at the best iterative point are only 1%. Therefore, the technique is conservative, safe and ...
3 Citations
#1Yang Xianhui (THU: Tsinghua University)H-Index: 2
A multivariate statistical process monitoring method was developed based on a similarity analysis of the operating data for on-line batch process monitoring.The similarity between the entire trajectory of a normal batch run and a predescribed reference trajectory is used as the monitoring index.The control limits are computed using the kernel density function.The on-line monitoring uses a Kalman filter which can estimate the entire trajectory of the current batch run.Comparison of the monitoring...
#1Yang Xianhui (THU: Tsinghua University)H-Index: 2
This paper preseants a method for cable/wireless hybrid packaging and transmitting Modbus messages in ZigBee networks.The frame structure and addressing method perform very well in both cable and wireless networks.Then the gateway design incorporates both software and hardware component to transform the Modbus message for input into the cable/wireless hybrid network,so the message can be transmitted in the ZigBee network.This solution extends the applications of Modbus cable/wireless hybrid tran...
Multiway kernel partial least squares(MKPLS)can be used for modeling and optimal control of batch processes.But the calculated optimal control policy based on the model may no longer be optimal,when applied to the actual process due to model-plant mismatches and unknown disturbances.Based on the similar idea between repetitive batch runs and iterations during numerical optimization,a batch-to-batch optimization correction strategy coupled with MKPLS model and sequential quadratic programming(SQP...
1 Citations
Using Multi-way Partial Least Squares(MPLS) model integrated with iterative learning control,the final quality control for batch processes is presented.Utilizing the repetitive nature of batch processes,the final quality deviations in each batch are implemented to adjust the control profile of the next batch run.The strategy can reject the deviations from the model mismatch and the disturbances that repeat themselves in the subsequent batches.The effectiveness of proposed method is validated wit...
#1Yang Xianhui (THU: Tsinghua University)H-Index: 2
Due to the influence of network transmissions on networked control systems(NCS),compensation and estimation for network-induced delays and packet dropout at the controller unit are proposed to improve the performance of control systems.Using a time driven sensor,an event and time driven controller and assuming that the delays are less than a sampling period with packet transmitted at a fixed rate,the system obtained by using the compensation and estimation methods for delays and packet drop in n...
1 Citations