A real-world localization system for wireless sensor networks that adapts for mobility and irregular radio propagation model is considered. The traditional range-based techniques and recent range-free localization sch...A real-world localization system for wireless sensor networks that adapts for mobility and irregular radio propagation model is considered. The traditional range-based techniques and recent range-free localization schemes are not well competent for localization in mobile sensor networks, while the probabilistic approach of Bayesian filtering with particle-based density representations provides a comprehensive solution to such localization problem. Monte Carlo localization is a Bayesian filtering method that approximates the mobile node's location by a set of weighted particles. In this paper, an enhanced Monte Carlo localization algorithm-Extended Monte Carlo Localization (Ext-MCL) is proposed, i.e., the traditional Monte Carlo localization algorithm is improved and extended to make it suitable for the practical wireless network environment where the radio propagation model is irregular. Simulation results show the proposal gets better localization accuracy and higher localizable node number than previously proposed Monte Carlo localization schemes not only for ideal radio model, but also for irregular one.展开更多
The interfacial evaporative heat transfer was included in the semi-empirical study of the heat transfer for the falling liquid film flow. The investigations showed that, the inclusion of the interfacial eveiporative h...The interfacial evaporative heat transfer was included in the semi-empirical study of the heat transfer for the falling liquid film flow. The investigations showed that, the inclusion of the interfacial eveiporative heat transfer in the turbulent model would lower the predicted convective heat transfer coefficient. Predictions of the new model resulted in a prominent deviation from that predictions of the normal model in the case of large mass flow rate and low wall heat flux. This deviation will be decreased with increasing wall heat flux, such that it will be asymptotic zero at very high wall heat flux. Predictions of the new model agreed well with the current experimental measurements. This study has verified that the Reynolds number is not the sole crucial parameter for heat transfer of falling liquid film flow, and wall heat flux will be another important independent parameter. This result is consistent with our previous studies.展开更多
Based on the Cluster Renewal Model of the particle motion in a CFB riser, a revised heat transfer model is developed, which introduces the latest research results of the hydrodynamics of the suspension flow in CFB. Th...Based on the Cluster Renewal Model of the particle motion in a CFB riser, a revised heat transfer model is developed, which introduces the latest research results of the hydrodynamics of the suspension flow in CFB. This model divides the heat transfer into two parts, which are due to the transient heat conduction by the covered clusters and the convection between the uncovered wall and the dispersed phase. Radiation at high temperature is regarded as being additive. The fraction of the covered wall by clusters is revised by a new formula, which is a function of the operating condition and the particle properties. The radiation between the dispersed phase and the uncovered wall includes not only the direct radiation to the uncovered wall, but also the radiation to the clusters and then reflected to the uncovered wall. Calculation was carried out for the CFB heat transfer model. The results were compared with the published typical experimental data of other researchers and showed a good agreement between them.展开更多
This paper investigates an approach to improve the engagement quality of controlled transfer clutch mode in 4 wheel drive(WD) car from three considerations of reducing friction,smoothening responsiveness and alleviati...This paper investigates an approach to improve the engagement quality of controlled transfer clutch mode in 4 wheel drive(WD) car from three considerations of reducing friction,smoothening responsiveness and alleviating jerk.The method utilizes an improved sliding mode control with genetic algorithm instead of simplified mode to determine appropriate values of parameters in control close- loop.The simulation results show that the method is effective for improving the engagement quality of coupling satisfying different design needs for 4WD car,as well as robustness even if input torque is changed at a certain range.展开更多
An infrared sensor using the liquid crystal chopper is presented. The infrared sensor is designed to detect infrared rays with a pyroelectric element used as a liquid crystal chopper in such an infrared sensor or the ...An infrared sensor using the liquid crystal chopper is presented. The infrared sensor is designed to detect infrared rays with a pyroelectric element used as a liquid crystal chopper in such an infrared sensor or the like.展开更多
基金the National Natural Science Foundation of China (No.60671033)the Research Fund for the Doctoral Program of Higher Education (No.20060614015).
文摘A real-world localization system for wireless sensor networks that adapts for mobility and irregular radio propagation model is considered. The traditional range-based techniques and recent range-free localization schemes are not well competent for localization in mobile sensor networks, while the probabilistic approach of Bayesian filtering with particle-based density representations provides a comprehensive solution to such localization problem. Monte Carlo localization is a Bayesian filtering method that approximates the mobile node's location by a set of weighted particles. In this paper, an enhanced Monte Carlo localization algorithm-Extended Monte Carlo Localization (Ext-MCL) is proposed, i.e., the traditional Monte Carlo localization algorithm is improved and extended to make it suitable for the practical wireless network environment where the radio propagation model is irregular. Simulation results show the proposal gets better localization accuracy and higher localizable node number than previously proposed Monte Carlo localization schemes not only for ideal radio model, but also for irregular one.
基金Supported by the National Natural Science Foundation of China (No. 59995550-3) and Science Funds from the Ministry of Education (No. 97000357).
文摘The interfacial evaporative heat transfer was included in the semi-empirical study of the heat transfer for the falling liquid film flow. The investigations showed that, the inclusion of the interfacial eveiporative heat transfer in the turbulent model would lower the predicted convective heat transfer coefficient. Predictions of the new model resulted in a prominent deviation from that predictions of the normal model in the case of large mass flow rate and low wall heat flux. This deviation will be decreased with increasing wall heat flux, such that it will be asymptotic zero at very high wall heat flux. Predictions of the new model agreed well with the current experimental measurements. This study has verified that the Reynolds number is not the sole crucial parameter for heat transfer of falling liquid film flow, and wall heat flux will be another important independent parameter. This result is consistent with our previous studies.
基金the Project of Outstanding Young University Teachers of Shanghai,No.03YQHB076. and R & D Fund of DonghuaUniversity
文摘Based on the Cluster Renewal Model of the particle motion in a CFB riser, a revised heat transfer model is developed, which introduces the latest research results of the hydrodynamics of the suspension flow in CFB. This model divides the heat transfer into two parts, which are due to the transient heat conduction by the covered clusters and the convection between the uncovered wall and the dispersed phase. Radiation at high temperature is regarded as being additive. The fraction of the covered wall by clusters is revised by a new formula, which is a function of the operating condition and the particle properties. The radiation between the dispersed phase and the uncovered wall includes not only the direct radiation to the uncovered wall, but also the radiation to the clusters and then reflected to the uncovered wall. Calculation was carried out for the CFB heat transfer model. The results were compared with the published typical experimental data of other researchers and showed a good agreement between them.
文摘This paper investigates an approach to improve the engagement quality of controlled transfer clutch mode in 4 wheel drive(WD) car from three considerations of reducing friction,smoothening responsiveness and alleviating jerk.The method utilizes an improved sliding mode control with genetic algorithm instead of simplified mode to determine appropriate values of parameters in control close- loop.The simulation results show that the method is effective for improving the engagement quality of coupling satisfying different design needs for 4WD car,as well as robustness even if input torque is changed at a certain range.
文摘An infrared sensor using the liquid crystal chopper is presented. The infrared sensor is designed to detect infrared rays with a pyroelectric element used as a liquid crystal chopper in such an infrared sensor or the like.
