During the process of aircraft design, the mathematical model of pilot control behavior characteristics is always used to predict aircraft flying qualities （FQ）. This is one of the important methods to avoid pilot-a...During the process of aircraft design, the mathematical model of pilot control behavior characteristics is always used to predict aircraft flying qualities （FQ）. This is one of the important methods to avoid pilot-aircraft adverse coupling. In order to study the FQ criterion based on closed-loop pilot-aircraft systems, first, an experimental database is built, which includes 40 aircraft dynamics configurations and the corresponding flight simulation results. Second, the mathematical pilot models with a set of different aircraft configurations are obtained by this experimental database. Then, two FQ criteria, Neal-Smith criterion and Moscow Aviation Institute （MAI） criterion, are analyzed. And the relationship between the FQ level evaluated by actual pilot and the parameters of closed-loop pilot-aircraft systems is studied. Finally, an improved criterion of aircraft FQ is built based on the above two criteria. This new criterion is further used to predict FQ for four new aircraft dynamics configurations, and the prediction results verify its accuracy and practicability.展开更多
BACKGROUND： Subjective discomforts in a preclinical range are often due to imbalanced autonomic nervous system activity, which is a focus of craniosacral therapy. OBJECTIVE： The aim of this work was to determine any...BACKGROUND： Subjective discomforts in a preclinical range are often due to imbalanced autonomic nervous system activity, which is a focus of craniosacral therapy. OBJECTIVE： The aim of this work was to determine any changes in heart rate variability （HRV） in a study on craniosacral therapy. DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS： This is a quasi-experimental （controlled） study with cross-over design. In a private practice, measurements were performed on 31 patients with subjective discomforts before and after a control and an intervention period. HRV was determined using a device that requires a measuring time of 140 s and electrode contact only with the fingertips. Main PRIMARY OUTCOME MEASURES： HRV change under the influence of a defined onetime intervention （test intervention） with craniosacral therapy versus control （defined rest period）. RESULTS： Standard deviation of all RR-intervals （ms） and total power of RR-interval variability in the frequency range （ms2） were together interpreted as an indicator of test subjects＇ autonomic nervous activity and as a measure of their ability to cope with demands on their health. Neither of these parameters increased during the control period （P〉0.05）, whereas during the test intervention period there was an increase in both （P〈0.05, P〈0.01）. Nevertheless, interactions between treatment and the increase were statistically not significant （P〉0.05）. No changes were observed in the low frequency/high frequency ratio （sympathetic-vagal balance） in the course of the control or the test intervention period （P〉0.05）. CONCLUSION： Craniosacral treatment had a favourable effect on autonomic nervous activity. This in itself is an interesting result, but further research will be needed to distinguish specific effects of craniosacral therapy technique from less specific therapist-client interaction effects.展开更多
By combining top-level design with local pilot practices,rural land system reform,as an important priority on the agenda of deepening comprehensive reform,has accumulated a series of replicable and applicable experien...By combining top-level design with local pilot practices,rural land system reform,as an important priority on the agenda of deepening comprehensive reform,has accumulated a series of replicable and applicable experiences that are conducive to amendments to relevant laws.This paper takes stock of the basic experience of Pidu District in addressing typical problems arising in its rural land system reform and then investigates the inner link between the reform and the persistence of high housing prices in cities,the capital flowing to the countryside,and the rural revitalization program.Based on this analysis,the author puts forward three basic directions of the rural land system reform:remain committed to marketization,balance the interests of all parties and promote the development of rural industries.展开更多
The establishment of Shanghai Pilot Free Trade Zone provides many possibilities for China's economic construction. This paper made a comparative analysis on investment management system of Shanghai Pilot Free Trad...The establishment of Shanghai Pilot Free Trade Zone provides many possibilities for China's economic construction. This paper made a comparative analysis on investment management system of Shanghai Pilot Free Trade Zone and traditional investment management system,discussed achievements and problems of reform of investment management system of Shanghai Pilot Free Trade Zone,and finally came up with pertinent policy recommendations.展开更多
The influence of cells groupings factor to the performance of the cells groupings time-shift pilot scheme is researched for the multiple cells large scale antennas systems（LSAS）. The former researches have confirmed...The influence of cells groupings factor to the performance of the cells groupings time-shift pilot scheme is researched for the multiple cells large scale antennas systems（LSAS）. The former researches have confirmed that the cells groupings time-shift pilots scheme is effective to reduce inter-cell interference, especially pilot contamination, which results from the pilot reuse in adjacent cells. However, they have not specified reasonable cells groupings factor, which plays a critical role in the general performance of the LSAS. Therefore, this problem is researched in details. The time for reverse-link data transmission will be compressed, when the groupings factor surpasses a certain range. Thus it is not always beneficial to increase the cells groupings factor without limitation. Furthermore,a reasonable cells groupings factor is deduced from the perspective of optimization to enhance the system performance. Simulations verify the proposed cell grouping factor.展开更多
To solve the flight safety problem caused by nonlinear instabilities（category II pilot induced oscillations, PIOs） of the closed-loop pilot-vehicle system with rate-limiting actuator, the antiwindup（AW） compensati...To solve the flight safety problem caused by nonlinear instabilities（category II pilot induced oscillations, PIOs） of the closed-loop pilot-vehicle system with rate-limiting actuator, the antiwindup（AW） compensation method to avoid category II PIOs is investigated. Firstly, the AW compensation method originally used for controlling input magnitude limited system is introduced, then this method is extended for controlling input rate-limiting system through a circle criterion theorem. Secondly, the establishment of the AW compensator is transformed into the solving of linear matrix inequalities. Finally, an AW compensator establishment algorithm for the closed-loop pilot-vehicle system with the rate-limiting actuator is obtained. The effectiveness of the AW compensation method to avoid category II PIOs is validated by time-domain simulations,and compared with rate-limited feedback（RLF） command rate compensation method. The results show that the AW compensation method can effectively suppress category II PIOs and maintain the nominal performance when the closed-loop pilot-vehicle system is normal. Unlike the command rate compensator which works upon system uninterruptedly, the AW compensation method affects the closed-loop pilot-vehicle system only when the rate-limiting of actuator is activated, so it is a novel PIO avoidance method.展开更多
高水平的军机飞行员岗位能力对于完成作战任务、保障飞行安全具有十分重要的意义。但是,目前关于军机飞行员岗位能力的影响因素及作用机制的研究却十分匮乏。为了构建军机飞行员岗位能力的影响因素指标体系,研究招募了30名合格军机飞行...高水平的军机飞行员岗位能力对于完成作战任务、保障飞行安全具有十分重要的意义。但是,目前关于军机飞行员岗位能力的影响因素及作用机制的研究却十分匮乏。为了构建军机飞行员岗位能力的影响因素指标体系,研究招募了30名合格军机飞行员以完成影响因素及其相互影响矩阵的调查,并综合应用决策试验与评估-综合对抗解释结构建模(decision making trial and evaluation-total adversarial interpretive structure modeling,DEMATEL-TAISM)方法进行分析。结果表明:①军机飞行员岗位能力影响因素指标体系由13项关键因素组成,可分成基础能力训练、理论知识训练、飞行训练和改换装训练这4类一级指标;②多任务/场景切换的操控能力、基本飞行操控能力、特情处置驾驶操控能力、战术基础理论、自我管理技能、职业体能是6个至关重要的影响因素,前三者的中心度(与其他因素的关联)最高,后三者的原因度(对其他因素的影响)最大;③对于军机飞行员岗位能力的生成,自我管理技能、职业体能和战术基础理论是最根本原因,空中战术能力、飞行后讲评和改装飞行驾驶技术是最直接原因。研究结果可进一步应用于军机飞行员岗位能力评估系统的开发。展开更多
The experiment system of 1000 m deep sea mining system is built up with the similarity theory. Sine mechanism is used to simulate mining ship to generate lateral shock excitation by ocean wave. Simulation and experime...The experiment system of 1000 m deep sea mining system is built up with the similarity theory. Sine mechanism is used to simulate mining ship to generate lateral shock excitation by ocean wave. Simulation and experiment of spherical joint connecting deep sea mining system has been done in band six marine conditions. The results indicate that the moment of spherical joint connecting deep sea mining is smaller than that of the thread connected ones, the lifting pipe of sphelical joint is ＂flexible pipe＂. The flexural torque of the articulated lifting pipe system in pump and buffer is generally periodic variation with some irregularity, the value is stable on 60 N·S, and it is obviously smaller than that of the fixed lifting pipe system; The total displacement exhibits cyclic variation pattern, and the periodicity of them is longer than that of sea current. The results of experiment and simulation are basically consistent. And the analysis in the paper offers theoretical foundation of 1000 m deep sea mining system in China.展开更多
基金Aeronautical Science Foundation of China (2006ZA51004)Fanzhou Foundation of China(20100506)
文摘During the process of aircraft design, the mathematical model of pilot control behavior characteristics is always used to predict aircraft flying qualities （FQ）. This is one of the important methods to avoid pilot-aircraft adverse coupling. In order to study the FQ criterion based on closed-loop pilot-aircraft systems, first, an experimental database is built, which includes 40 aircraft dynamics configurations and the corresponding flight simulation results. Second, the mathematical pilot models with a set of different aircraft configurations are obtained by this experimental database. Then, two FQ criteria, Neal-Smith criterion and Moscow Aviation Institute （MAI） criterion, are analyzed. And the relationship between the FQ level evaluated by actual pilot and the parameters of closed-loop pilot-aircraft systems is studied. Finally, an improved criterion of aircraft FQ is built based on the above two criteria. This new criterion is further used to predict FQ for four new aircraft dynamics configurations, and the prediction results verify its accuracy and practicability.
文摘BACKGROUND： Subjective discomforts in a preclinical range are often due to imbalanced autonomic nervous system activity, which is a focus of craniosacral therapy. OBJECTIVE： The aim of this work was to determine any changes in heart rate variability （HRV） in a study on craniosacral therapy. DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS： This is a quasi-experimental （controlled） study with cross-over design. In a private practice, measurements were performed on 31 patients with subjective discomforts before and after a control and an intervention period. HRV was determined using a device that requires a measuring time of 140 s and electrode contact only with the fingertips. Main PRIMARY OUTCOME MEASURES： HRV change under the influence of a defined onetime intervention （test intervention） with craniosacral therapy versus control （defined rest period）. RESULTS： Standard deviation of all RR-intervals （ms） and total power of RR-interval variability in the frequency range （ms2） were together interpreted as an indicator of test subjects＇ autonomic nervous activity and as a measure of their ability to cope with demands on their health. Neither of these parameters increased during the control period （P〉0.05）, whereas during the test intervention period there was an increase in both （P〈0.05, P〈0.01）. Nevertheless, interactions between treatment and the increase were statistically not significant （P〉0.05）. No changes were observed in the low frequency/high frequency ratio （sympathetic-vagal balance） in the course of the control or the test intervention period （P〉0.05）. CONCLUSION： Craniosacral treatment had a favourable effect on autonomic nervous activity. This in itself is an interesting result, but further research will be needed to distinguish specific effects of craniosacral therapy technique from less specific therapist-client interaction effects.
基金part of the periodical research achievements of “Research on the Integration of Core Values of Equality and Justice into Property Rights Protection Legislation”(18VHJ007)a key program funded by the National Social Science Foundation in 2018
文摘By combining top-level design with local pilot practices,rural land system reform,as an important priority on the agenda of deepening comprehensive reform,has accumulated a series of replicable and applicable experiences that are conducive to amendments to relevant laws.This paper takes stock of the basic experience of Pidu District in addressing typical problems arising in its rural land system reform and then investigates the inner link between the reform and the persistence of high housing prices in cities,the capital flowing to the countryside,and the rural revitalization program.Based on this analysis,the author puts forward three basic directions of the rural land system reform:remain committed to marketization,balance the interests of all parties and promote the development of rural industries.
文摘The establishment of Shanghai Pilot Free Trade Zone provides many possibilities for China's economic construction. This paper made a comparative analysis on investment management system of Shanghai Pilot Free Trade Zone and traditional investment management system,discussed achievements and problems of reform of investment management system of Shanghai Pilot Free Trade Zone,and finally came up with pertinent policy recommendations.
基金supported by the National Natural Science Foundation of China(6110602261574013)
文摘The influence of cells groupings factor to the performance of the cells groupings time-shift pilot scheme is researched for the multiple cells large scale antennas systems（LSAS）. The former researches have confirmed that the cells groupings time-shift pilots scheme is effective to reduce inter-cell interference, especially pilot contamination, which results from the pilot reuse in adjacent cells. However, they have not specified reasonable cells groupings factor, which plays a critical role in the general performance of the LSAS. Therefore, this problem is researched in details. The time for reverse-link data transmission will be compressed, when the groupings factor surpasses a certain range. Thus it is not always beneficial to increase the cells groupings factor without limitation. Furthermore,a reasonable cells groupings factor is deduced from the perspective of optimization to enhance the system performance. Simulations verify the proposed cell grouping factor.
基金supported by the National Basic Research Program(973Program)(2015CB755805)the National Natural Science Foundation of China(61374145)
文摘To solve the flight safety problem caused by nonlinear instabilities（category II pilot induced oscillations, PIOs） of the closed-loop pilot-vehicle system with rate-limiting actuator, the antiwindup（AW） compensation method to avoid category II PIOs is investigated. Firstly, the AW compensation method originally used for controlling input magnitude limited system is introduced, then this method is extended for controlling input rate-limiting system through a circle criterion theorem. Secondly, the establishment of the AW compensator is transformed into the solving of linear matrix inequalities. Finally, an AW compensator establishment algorithm for the closed-loop pilot-vehicle system with the rate-limiting actuator is obtained. The effectiveness of the AW compensation method to avoid category II PIOs is validated by time-domain simulations,and compared with rate-limited feedback（RLF） command rate compensation method. The results show that the AW compensation method can effectively suppress category II PIOs and maintain the nominal performance when the closed-loop pilot-vehicle system is normal. Unlike the command rate compensator which works upon system uninterruptedly, the AW compensation method affects the closed-loop pilot-vehicle system only when the rate-limiting of actuator is activated, so it is a novel PIO avoidance method.
文摘高水平的军机飞行员岗位能力对于完成作战任务、保障飞行安全具有十分重要的意义。但是,目前关于军机飞行员岗位能力的影响因素及作用机制的研究却十分匮乏。为了构建军机飞行员岗位能力的影响因素指标体系,研究招募了30名合格军机飞行员以完成影响因素及其相互影响矩阵的调查,并综合应用决策试验与评估-综合对抗解释结构建模(decision making trial and evaluation-total adversarial interpretive structure modeling,DEMATEL-TAISM)方法进行分析。结果表明:①军机飞行员岗位能力影响因素指标体系由13项关键因素组成,可分成基础能力训练、理论知识训练、飞行训练和改换装训练这4类一级指标;②多任务/场景切换的操控能力、基本飞行操控能力、特情处置驾驶操控能力、战术基础理论、自我管理技能、职业体能是6个至关重要的影响因素,前三者的中心度(与其他因素的关联)最高,后三者的原因度(对其他因素的影响)最大;③对于军机飞行员岗位能力的生成,自我管理技能、职业体能和战术基础理论是最根本原因,空中战术能力、飞行后讲评和改装飞行驾驶技术是最直接原因。研究结果可进一步应用于军机飞行员岗位能力评估系统的开发。
基金This research was financially supported by China Ocean Mineral Resources Reasearch and Design Association (GrantNo DY105-03-02-17)Ph.D Programs Foundation of Ministry of Education of China (Grant No20060008025)
文摘The experiment system of 1000 m deep sea mining system is built up with the similarity theory. Sine mechanism is used to simulate mining ship to generate lateral shock excitation by ocean wave. Simulation and experiment of spherical joint connecting deep sea mining system has been done in band six marine conditions. The results indicate that the moment of spherical joint connecting deep sea mining is smaller than that of the thread connected ones, the lifting pipe of sphelical joint is ＂flexible pipe＂. The flexural torque of the articulated lifting pipe system in pump and buffer is generally periodic variation with some irregularity, the value is stable on 60 N·S, and it is obviously smaller than that of the fixed lifting pipe system; The total displacement exhibits cyclic variation pattern, and the periodicity of them is longer than that of sea current. The results of experiment and simulation are basically consistent. And the analysis in the paper offers theoretical foundation of 1000 m deep sea mining system in China.
