To analyze the parachute dynamics and stability characteristics of precision airdrop system, the fluid-structure interaction （FSI） dynamics coupling with the flight trajectory of a para- chute payload system is comp...To analyze the parachute dynamics and stability characteristics of precision airdrop system, the fluid-structure interaction （FSI） dynamics coupling with the flight trajectory of a para- chute payload system is comprehensively predicted by numerical methods. The inflation behavior of a disk-gap-band parachute is specifically investigated using the arbitrary Lagrangian Euler （ALE） penalty coupling method. With the available aerodynamic data obtained from the FSI sim- ulation, a nine-degree-of-freedom （9DOF） dynamic model of a parachute-payload system is built and solved to simulate the descent trajectory of the multi-body dynamic system. Finally, a linear five-degree-of-freedom （5DOF） dynamic model is developed, the perturbation characteristics and the motion laws of the parachute and payload under a wind gust are analyzed by the linearization method and verified by a comparison with flight test data. The results of airdrop test demonstrate that our method can be further applied to the guidance and control of precision airdrop systems.展开更多
This study investigated whether adults who stutter and normal adult speakers differ in the production of stop consonants in fluent reading Chinese Putonghua speech.Voice onset time（VOT） was measured and the spectral...This study investigated whether adults who stutter and normal adult speakers differ in the production of stop consonants in fluent reading Chinese Putonghua speech.Voice onset time（VOT） was measured and the spectral moments at the stop burst were calculated for the stutterers（both before and after the speech therapy） and also for the nonstutterers. The statistical results showed that there were no significant differences in VOT between the nonstutterers and stutterers either prior to or after therapy,although the mean VOT of the stutterers was slightly greater than that of the nonstutterers.The results also indicated that both the obstruction place and the subsequent syllabic final exhibited an influence to a greater extent on VOT for the stutterers.In the spectral domain,the spectral mean of the stuttering participants before therapy was significantly different from that of the normal participants, whereas the group difference became insignificant after the therapy session.The smaller spectral mean for the stutterers might be interpreted as a more posterior occlusion in the oral cavity when producing alveolars and velars.In addition,productions of the stutterers scattered with a wider range in the space of spectral moments.Furthermore,the smaller main effect of syllabic finals on the mean spectral frequency of the burst suggested that the stutterers exhibited weaker anticipatory coarticulation than the nonstutterers.展开更多
A forced alignment based algorithms to detect Chinese repetitive stuttering is studied. According to the features of repetitions in Chinese stuttered speech,improvement solutions are provided based on the previous res...A forced alignment based algorithms to detect Chinese repetitive stuttering is studied. According to the features of repetitions in Chinese stuttered speech,improvement solutions are provided based on the previous research findings.First,a multi-span looping forced alignment decoding networks is designed to detect multi-syllable repetitions in Chinese stuttered speech.Second,branch penalty factor is added in the networks to adjust decoding trend using recursive search in order to reduce the error from the complexity of the decoding networks. Finally,we re-judge the detected stutters by calculating confidence to improve the reliability of the detection result.The experimental results show that compared to previous algorithm,the proposed algorithm can improve system performance significantly,about 18%average detection error rate relatively.展开更多
基金co-supported by Research Project of Chinese National University of Defense Technology(No.:JC13-0104)the National Natural Science Foundation of China(Nos.:51375486 and 11272345)the found support from China Scholarship Council(CSC)
文摘To analyze the parachute dynamics and stability characteristics of precision airdrop system, the fluid-structure interaction （FSI） dynamics coupling with the flight trajectory of a para- chute payload system is comprehensively predicted by numerical methods. The inflation behavior of a disk-gap-band parachute is specifically investigated using the arbitrary Lagrangian Euler （ALE） penalty coupling method. With the available aerodynamic data obtained from the FSI sim- ulation, a nine-degree-of-freedom （9DOF） dynamic model of a parachute-payload system is built and solved to simulate the descent trajectory of the multi-body dynamic system. Finally, a linear five-degree-of-freedom （5DOF） dynamic model is developed, the perturbation characteristics and the motion laws of the parachute and payload under a wind gust are analyzed by the linearization method and verified by a comparison with flight test data. The results of airdrop test demonstrate that our method can be further applied to the guidance and control of precision airdrop systems.
基金supported by the National Natural Science Foundation of China(10874203,10925419, 90920302,61072124,11074275,11161140319,91120001,61271426)Strategic Priority Research Program of the Chinese Academy of Sciences(XDA06030100,XDA06030500)+1 种基金National 863 Program(2012AA012503)CAS Priority Deployment Project(KGZD-EW-103-2)
文摘This study investigated whether adults who stutter and normal adult speakers differ in the production of stop consonants in fluent reading Chinese Putonghua speech.Voice onset time（VOT） was measured and the spectral moments at the stop burst were calculated for the stutterers（both before and after the speech therapy） and also for the nonstutterers. The statistical results showed that there were no significant differences in VOT between the nonstutterers and stutterers either prior to or after therapy,although the mean VOT of the stutterers was slightly greater than that of the nonstutterers.The results also indicated that both the obstruction place and the subsequent syllabic final exhibited an influence to a greater extent on VOT for the stutterers.In the spectral domain,the spectral mean of the stuttering participants before therapy was significantly different from that of the normal participants, whereas the group difference became insignificant after the therapy session.The smaller spectral mean for the stutterers might be interpreted as a more posterior occlusion in the oral cavity when producing alveolars and velars.In addition,productions of the stutterers scattered with a wider range in the space of spectral moments.Furthermore,the smaller main effect of syllabic finals on the mean spectral frequency of the burst suggested that the stutterers exhibited weaker anticipatory coarticulation than the nonstutterers.
基金supported by the National Natural Science Foundation of China(10925419,90920302, 61072124,11074275,11161140319,91120001,61271426)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA06030100,XDA06030500)+1 种基金the National 863 Program(2012AA012503)the CAS Priority Deployment Project(KGZD-EW-103-2)
文摘A forced alignment based algorithms to detect Chinese repetitive stuttering is studied. According to the features of repetitions in Chinese stuttered speech,improvement solutions are provided based on the previous research findings.First,a multi-span looping forced alignment decoding networks is designed to detect multi-syllable repetitions in Chinese stuttered speech.Second,branch penalty factor is added in the networks to adjust decoding trend using recursive search in order to reduce the error from the complexity of the decoding networks. Finally,we re-judge the detected stutters by calculating confidence to improve the reliability of the detection result.The experimental results show that compared to previous algorithm,the proposed algorithm can improve system performance significantly,about 18%average detection error rate relatively.
