The hybrid carrier(HC)system rooted in the carrier fusion concept is gradually garnering attention.In this paper,we study the extended hybrid carrier(EHC)multiple access scheme to ensure reliable wireless communicatio...The hybrid carrier(HC)system rooted in the carrier fusion concept is gradually garnering attention.In this paper,we study the extended hybrid carrier(EHC)multiple access scheme to ensure reliable wireless communication.By employing the EHC modulation,a power layered multiplexing framework is realized,which exhibits enhanced interference suppression capability owing to the more uniform energy distribution design.The implementation method and advantage mechanism are explicated respectively for the uplink and downlink,and the performance analysis under varying channel conditions is provided.In addition,considering the connectivity demand,we explore the non-orthogonal multiple access(NOMA)method of the EHC system and develop the EHC sparse code multiple access scheme.The proposed scheme melds the energy spread superiority of EHC with the access capacity of NOMA,facilitating superior support for massive connectivity in high mobility environments.Simulation results have verified the feasibility and advantages of the proposed scheme.Compared with existing HC multiple access schemes,the proposed scheme exhibits robust bit error rate performance and can better guarantee multiple access performance in complex scenarios of nextgeneration communications.展开更多
The possibility of multiplicity in an isothermal continuous mixed suspension-mixed product removalcrystallizer is explored using the bifurcation theory. A process involving agglomeration controlled precipitationis con...The possibility of multiplicity in an isothermal continuous mixed suspension-mixed product removalcrystallizer is explored using the bifurcation theory. A process involving agglomeration controlled precipitationis considered in which secondary nucleation occurs simultaneously with primary nucleation. The determinantequations for the existence of multiple steady states are developed and the multiplicity boundaries dependent on thephysical and kinetic properties and operational parameters of the process are obtained by resolving these determinantequations. The number of steady states in the precipitator for various multiplicity regions is determined and thelinear stability of these steady states is analyzed by using the Routh criterion.展开更多
AIM: To report the results of fixed-fulcrum fully constrained reverse shoulder arthroplasty for the treatment of recurrent shoulder instability in patients with epilepsy. METHODS: A retrospective review was conducted ...AIM: To report the results of fixed-fulcrum fully constrained reverse shoulder arthroplasty for the treatment of recurrent shoulder instability in patients with epilepsy. METHODS: A retrospective review was conducted at a single facility. Cases were identified using a com-puterized database and all clinic notes and operative reports were reviewed. All patients with epilepsy and recurrent shoulder instability were included for study. Between July 2003 and August 2011 five shoulders in five consecutive patients with epilepsy underwent fixed-fulcrum fully constrained reverse shoulder arthroplasty for recurrent anterior shoulder instability. The mean duration of epilepsy in the cohort was 21 years(range, 5-51) and all patients suffered from grand mal seizures. RESULTS: Mean age at the time of surgery was 47 years(range, 32-64). The cohort consisted of four males and one female. Mean follow-up was 4.7 years(range, 4.3-5 years). There were no further episodes of instability, and no further stabilisation or revision procedures were performed. The mean Oxford shoulder instability score improved from 8 preoperatively(range, 5-15) to 30 postoperatively(range, 16-37)(P = 0.015) and the mean subjective shoulder value improved from 20(range, 0-50) preoperatively to 60(range, 50-70) postoperatively(P = 0.016). Mean active forward elevation improved from 71° preoperatively(range,45°-130°) to 100° postoperatively(range, 80°-90°) and mean active external rotation improved from 15° preoperatively(range, 0°-30°) to 40°(20°-70°) postoperatively. No cases of scapular notching or loosening were noted. CONCLUSION: Fixed-fulcrum fully constrained reverse shoulder arthroplasty should be considered for the treatment of recurrent shoulder instability in patients with epilepsy.展开更多
A double-tracked robot is designed from mechanical and control perspectives,which consists of two segments connected with a swing joint. As the angle between the two segments of the robot platform can be changed,the r...A double-tracked robot is designed from mechanical and control perspectives,which consists of two segments connected with a swing joint. As the angle between the two segments of the robot platform can be changed,the robot can move like a four-tracked robot on many terrains. The center of gravity（ CG） kinematics model is established,which plays an important role in the process of traveling over obstacles and climbing up stairs. Using this model,the CG change situation and the maximal height of the climbable obstacle are obtained. Then the relationship between the robot pitch angle and the height of the obstacle is established. Finally,a reasonable system structure for the robot is designed and its kinematics analysis for obstacle-surmounting capability is conducted through experiments.展开更多
Based on the contact equivalent relation of smooth map-germs in singularity theory, the stability of equivariant bifurcation problems with two types of state variables and their unfoldings in the presence of parameter...Based on the contact equivalent relation of smooth map-germs in singularity theory, the stability of equivariant bifurcation problems with two types of state variables and their unfoldings in the presence of parameter symmetry is discussed. Some basic results are obtained. Transversality condition is used to characterize the stability of equavariant bifurcation problems.展开更多
In this paper the amalgamation of (I+1)×J tables under consistent significance is considered and the sufficient condition is obtained. The sufficient and necessary conditions are given to avoid the famous paradox...In this paper the amalgamation of (I+1)×J tables under consistent significance is considered and the sufficient condition is obtained. The sufficient and necessary conditions are given to avoid the famous paradoxes 'YAP' and 'YRP'. A practical algorithm is given to compute the critical value when pooling tables with odds ratio less than 1.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant U23A20278in part by the National Natural Science Foundation of China under Grant 62171151in part by the Fundamental Research Funds for the Central Universities under Grant HIT.OCEF.2021012。
文摘The hybrid carrier(HC)system rooted in the carrier fusion concept is gradually garnering attention.In this paper,we study the extended hybrid carrier(EHC)multiple access scheme to ensure reliable wireless communication.By employing the EHC modulation,a power layered multiplexing framework is realized,which exhibits enhanced interference suppression capability owing to the more uniform energy distribution design.The implementation method and advantage mechanism are explicated respectively for the uplink and downlink,and the performance analysis under varying channel conditions is provided.In addition,considering the connectivity demand,we explore the non-orthogonal multiple access(NOMA)method of the EHC system and develop the EHC sparse code multiple access scheme.The proposed scheme melds the energy spread superiority of EHC with the access capacity of NOMA,facilitating superior support for massive connectivity in high mobility environments.Simulation results have verified the feasibility and advantages of the proposed scheme.Compared with existing HC multiple access schemes,the proposed scheme exhibits robust bit error rate performance and can better guarantee multiple access performance in complex scenarios of nextgeneration communications.
文摘The possibility of multiplicity in an isothermal continuous mixed suspension-mixed product removalcrystallizer is explored using the bifurcation theory. A process involving agglomeration controlled precipitationis considered in which secondary nucleation occurs simultaneously with primary nucleation. The determinantequations for the existence of multiple steady states are developed and the multiplicity boundaries dependent on thephysical and kinetic properties and operational parameters of the process are obtained by resolving these determinantequations. The number of steady states in the precipitator for various multiplicity regions is determined and thelinear stability of these steady states is analyzed by using the Routh criterion.
文摘AIM: To report the results of fixed-fulcrum fully constrained reverse shoulder arthroplasty for the treatment of recurrent shoulder instability in patients with epilepsy. METHODS: A retrospective review was conducted at a single facility. Cases were identified using a com-puterized database and all clinic notes and operative reports were reviewed. All patients with epilepsy and recurrent shoulder instability were included for study. Between July 2003 and August 2011 five shoulders in five consecutive patients with epilepsy underwent fixed-fulcrum fully constrained reverse shoulder arthroplasty for recurrent anterior shoulder instability. The mean duration of epilepsy in the cohort was 21 years(range, 5-51) and all patients suffered from grand mal seizures. RESULTS: Mean age at the time of surgery was 47 years(range, 32-64). The cohort consisted of four males and one female. Mean follow-up was 4.7 years(range, 4.3-5 years). There were no further episodes of instability, and no further stabilisation or revision procedures were performed. The mean Oxford shoulder instability score improved from 8 preoperatively(range, 5-15) to 30 postoperatively(range, 16-37)(P = 0.015) and the mean subjective shoulder value improved from 20(range, 0-50) preoperatively to 60(range, 50-70) postoperatively(P = 0.016). Mean active forward elevation improved from 71° preoperatively(range,45°-130°) to 100° postoperatively(range, 80°-90°) and mean active external rotation improved from 15° preoperatively(range, 0°-30°) to 40°(20°-70°) postoperatively. No cases of scapular notching or loosening were noted. CONCLUSION: Fixed-fulcrum fully constrained reverse shoulder arthroplasty should be considered for the treatment of recurrent shoulder instability in patients with epilepsy.
基金Supported by the National Natural Science Foundation(61273344)Ph.D. Program Foundation of Ministry of Education of China(20121101110011)+1 种基金Fundamental Research Fund of Beijing Institute of Technology(20130242009)State Key Laboratory of Robotics and Systems(HIT)(SKLRS-2011-ZD-06,SKLRS-2013-MS-10)
文摘A double-tracked robot is designed from mechanical and control perspectives,which consists of two segments connected with a swing joint. As the angle between the two segments of the robot platform can be changed,the robot can move like a four-tracked robot on many terrains. The center of gravity（ CG） kinematics model is established,which plays an important role in the process of traveling over obstacles and climbing up stairs. Using this model,the CG change situation and the maximal height of the climbable obstacle are obtained. Then the relationship between the robot pitch angle and the height of the obstacle is established. Finally,a reasonable system structure for the robot is designed and its kinematics analysis for obstacle-surmounting capability is conducted through experiments.
基金Project supported by the National Natural Science Foundation of China(No.10671002)the Natural Science Foundation of Hunan Province of China(No.04JJ3072)the Science Foundation of the Education Department of Hunan Province of China(No.04C383)
文摘Based on the contact equivalent relation of smooth map-germs in singularity theory, the stability of equivariant bifurcation problems with two types of state variables and their unfoldings in the presence of parameter symmetry is discussed. Some basic results are obtained. Transversality condition is used to characterize the stability of equavariant bifurcation problems.
文摘In this paper the amalgamation of (I+1)×J tables under consistent significance is considered and the sufficient condition is obtained. The sufficient and necessary conditions are given to avoid the famous paradoxes 'YAP' and 'YRP'. A practical algorithm is given to compute the critical value when pooling tables with odds ratio less than 1.
