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Influences of different time intervals between loop electrosurgical excision and abdominal hysterectomy or radical hysterectomy on postoperative complications: a retrospective analysis 被引量:5
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作者 Qu Haina Zhang Yan Zhang Junjie Hui Ning Xu Mingjuan 《Journal of Medical Colleges of PLA(China)》 CAS 2010年第1期38-43,共6页
Objective: To study the influences of different time intervals between loop electrosurgical excision (LEEP) and abdominal hysterectomy or radical hysterectomy on postoperative complications. Methods: Sixty-eight p... Objective: To study the influences of different time intervals between loop electrosurgical excision (LEEP) and abdominal hysterectomy or radical hysterectomy on postoperative complications. Methods: Sixty-eight patients, who received subsequent abdominal hysterectomy or radical hysterectomy after LEEP due to C1N III and cervical cancer (IA1, IA2 and IB1), were included in the present study. The hospital and clinic records of these patients were reviewed. The patients were divided into three groups according to the time intervals between LEEP and hysterectomy or radical hysterectomy: group l(within 48 h), group 2 (between 48 h to 6 weeks), and group 3(〉 6 weeks ).Results: General characteristics of patients, including the mean age, delivery history, BMI, menopausal status, clinical stage and HPV infection, were comparable between patients of different groups. There were no significant differences in the mean transfusion amount, posthysterectomy hospital stay or operation time between different groups. The frequencies and spectrum of complications were not significantly affected by the time interval between LEEP and hysterectomy or radical hysterectomy. Conclusion: It is concluded that whenever the LEEP is done, the operation including hysterectomy or radical hysterectomy can be conducted at any time as it is necessary for the patients. 展开更多
关键词 LEEP HYSTERECTOMY Radical hysterectomy time interval CIN III Early cervical cancer
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Vitreoretinal surgeons'experience and time interval from pars-plana vitrectomy to cataract extraction 被引量:1
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作者 Yan-Xin Xu Liang-Ping Liu +4 位作者 Jian-Bing Li Huan-Huan Cheng Min Hou Lin Lu Ming-Xing Wu 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2021年第1期120-126,共7页
AIM:To identify the association of the vitreoretinal surgeons'experience with the time interval between parsplana vitrectomy(PPV)and cataract extraction(CE).METHODS:Eyes with prior PPV and following CE were includ... AIM:To identify the association of the vitreoretinal surgeons'experience with the time interval between parsplana vitrectomy(PPV)and cataract extraction(CE).METHODS:Eyes with prior PPV and following CE were included in this retrospective cohort study.The years of practice and the annual case volume were used to describe the surgeons'experience.Multivariable linear regression analysis was used to investigate the relationship between surgeons'experience and the time interval adjusted for the patients age,gender,intraocular tamponade,and case complexity.RESULTS:Of 132430 eyes,1445 eyes were included in this study.In multivariable linear regression analysis,cases performed by surgeons with>20 practice years had longer time intervals compared with surgeons with<10 practice years after adjusted for other variables(β=0.329,95%CI:0.113 to 0.549,P=0.003).No difference in time interval was detected for comparing the lowest with the highest volume groups(β=0.089,95%CI:-0.164 to 0.343,P=0.343).The surgeons'practice years were not directly with the volume.For complicated surgery,the higherpractice-year surgeons had longer time interval than lowerpractice-year surgeons.CONCLUSION:The time intervals from PPV to CE is longer in higher-practice-year surgeons.The surgeons'practice years may have a greater effect on the time interval than annual case volume in high-complexity cases.Matching the complexity of vitreoretinal diseases with the surgeons'practice year should be considered. 展开更多
关键词 pars-plana vitrectomy cataract time interval EXPERIENCE annual case volume
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Study on conveyor natural frequency and time intervalfor switching off resistances 被引量:3
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作者 李光布 杨汝清 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2004年第6期685-689,共5页
A conveyor belt driven by wound rotor motors produces dynamic tension, velocity and accelerationduring starting. The terrible situation (such as resonance) in dynamic analysis and design is that system naturalfrequenc... A conveyor belt driven by wound rotor motors produces dynamic tension, velocity and accelerationduring starting. The terrible situation (such as resonance) in dynamic analysis and design is that system naturalfrequencies are equal to those for switching off electric resistances. This paper analyzes and determines systemnatural frequencies based on a modeling method of receptances with the analysis of sub-systems model and of theprinciple of their addition and conveyor loop closure. It also puts forward to calculate the time interval for switching off electric resistances. The starting of one conveyor is simulated by lumped-mass-spring-model software tofurther illustrate the influence of time interval for switching off electric resistances on conveyor dynamic behavior. Two methods are also compared. The receptance model is proved to be an excellent alternative. 展开更多
关键词 natural frequency receptance model switching-off time interval conveyor dynamic behavior
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Discussion of the Horizontal Intensity of Late Quaternary Fault Activity Along the Tianjingshan Fault Zone in Different Time Intervals and Fault Segments 被引量:1
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作者 Chai Chizhang,Zhang Weiqi,and Jiao DechengSeismological Bureau of Ningxia Hui Autonomous Region,Yinchuan 750001,China 《Earthquake Research in China》 1997年第3期25-32,共8页
By computing and classifying the data of gully offset obtained from field surveys along the Tianjingshan fault zone and estimating the ages of three types of gullies,the strike-slip rates along the fault zone are disc... By computing and classifying the data of gully offset obtained from field surveys along the Tianjingshan fault zone and estimating the ages of three types of gullies,the strike-slip rates along the fault zone are discussed in different time intervals and fault segments.The results suggest that the intensity of activity along the fault zone is not strong,but the differences between different time intervals and fault segments since the late Pleistocene have been obvious.The average rates range from 0.23 mm/a to 1.62 mm/a.The largest average rate is 1.40 mm/a,which occurred in the early and middle of late Pleistocene along the western segment of the fault zone.Since the late stage of the late Pleistocene,the center of faulting activity of the fault zone has shifted to the middle segment,and the average slip rates range have changed from 1.30 mm/a to 1.63 mm/a. 展开更多
关键词 Discussion of the Horizontal Intensity of Late Quaternary Fault Activity Along the Tianjingshan Fault Zone in Different time intervals and Fault Segments Activity
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TIME INTERVAL APPROACH TO THE PULSED NEUTRON LOGGING METHOD
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作者 赵经武 苏为宁 《Nuclear Science and Techniques》 SCIE CAS CSCD 1994年第2期118-123,共6页
The time interval of neibouring neutrons emitted from a steady state neutron source can be treated as that from a time-dependent neutron source. In the rockspace, the neutron flux is given by the neutron diffusion equ... The time interval of neibouring neutrons emitted from a steady state neutron source can be treated as that from a time-dependent neutron source. In the rockspace, the neutron flux is given by the neutron diffusion equation and is composedof an infinite number of 'modes'. Each 'mode' is composed of two die-away curves.The delay action has been discussed and used to measure the time interval withonly one detector in the experimellt. Nuclear reactions with the time distributiondue to different types of radiations observed in the neutron well-logging methods arepresented with a view to getting the rock nuclear parameters from the time intervaltechnique. 展开更多
关键词 time interval Steady state neutron source Delay action Neutronlogging method
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Time Intervals of the Electron Transitions between the Energy States in the Hydrogen Atom Calculated in a Non-Probabilistic Way 被引量:1
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作者 Stanislaw Olszewski 《Journal of Modern Physics》 2019年第13期1522-1531,共10页
Definitions of the mechanical parameters entering the Bohr model of the hydrogen atom allowed us to calculate the time intervals connected with the electron transitions between the nearest-neighbouring energy levels i... Definitions of the mechanical parameters entering the Bohr model of the hydrogen atom allowed us to calculate the time intervals connected with the electron transitions between the nearest-neighbouring energy levels in the atom. This is done in a strictly non-probabilistic way. The time results are compared with those derived earlier on the basis of the classical Joule-Lenz law for the energy emission adapted to the case of the electron transfer in the quantum systems. A similar formalism has been next applied to the harmonic oscillator and a particle moving in the one-dimensional potential box. 展开更多
关键词 Spectrum of the Hydrogen Atom time intervals of the Electron Transitions
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Estimation of the Gauging and the Calibration Time Interval for the Modern Total Stations
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作者 Evangelia Lambrou Antonios Antonakakis 《Journal of Civil Engineering and Architecture》 2015年第10期1210-1216,共7页
The modern TSs (total stations) have reached a very high level in the provided reading and reliability (accuracy and precision) of their measurements. The evolution of the digital technology has helped in this dir... The modern TSs (total stations) have reached a very high level in the provided reading and reliability (accuracy and precision) of their measurements. The evolution of the digital technology has helped in this direction. Thus, the TSs can support all requirements for the stake out and monitoring of modern survey engineering and constructions projects. Their complicated manufacturing process and the sensitivity of their components require gauging, adjusting and calibration at certain time intervals. This appears to be the only way in order to assure the precision of measurements provided by the manufacturer and the reliability of the works they are used for. The goal of this paper is to propose a method for the estimation of the gauging time interval for modern YSs. which could be used by any user. More specifically, the indispensable need for the TSs gauging is elevated and documented. All the parameters that influence their operation are registered. A model expressed by a scale of grades is defined, leading thus to an equation for the calculation of the time interval for the next needed gauging and calibration. 展开更多
关键词 Total station metrological check gauging CALIBRATION time interval.
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Multi-Mode Resource Constrained Project Scheduling Models for Progress and Equal Time Interval Payments
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作者 Yan Shangyao Wang Sin-Siang +1 位作者 Chen Miawjane Liu Jzu-Chun 《Journal of Modern Accounting and Auditing》 2014年第12期1187-1200,共14页
This study utilizes a time-precedence network technique to construct two models of multi-mode resource constrained project scheduling problem with discounted cash flows (MRCPSPDCF), individually including the progre... This study utilizes a time-precedence network technique to construct two models of multi-mode resource constrained project scheduling problem with discounted cash flows (MRCPSPDCF), individually including the progress payment (PP) and the payment at an equal time interval (ETI). The objective of each model is to maximize the net present value (NPV) for all cash flows in the project, subject to the related operational constraints. The models are characterized as NP-hard. A heuristic algorithm, coupled with two upper bound solutions, is proposed to efficiently solve the models and evaluate the heuristic algorithm performance which was not performed in past studies. The results show that the performance of proposed models and heuristic algorithm is good. 展开更多
关键词 project scheduling problem multi-mode resource constrained project scheduling problem with discountedcash flows (MRCPSPDCF) progress payment (PP) payment at an equal time interval (ETI) time-precedence network
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A New Method to Identify the Maximum Time Interval between Individual Events in Compound Rainstorm and Heatwave Events
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作者 Junlin Zhang Wei Xu +3 位作者 Yu Qiao Xinli Liao Chenna Meng Qinmei Han 《International Journal of Disaster Risk Science》 SCIE CSCD 2024年第3期453-466,共14页
Growing evidence indicates that extreme heat and rain may occur in succession within short time periods and cause greater impacts than individual events separated in time and space.Therefore,many studies have examined... Growing evidence indicates that extreme heat and rain may occur in succession within short time periods and cause greater impacts than individual events separated in time and space.Therefore,many studies have examined the impacts of compound hazard events on the social-ecological system at various scales.The definition of compound events is fundamental for such research.However,there are no existing studies that support the determination of time interval between individual events of a compound rainstorm and heatwave(CRH)event,which consists of two or more potentially qualifying component heatwave and rainstorm events.To address the deficiency in defining what individual events can constitute a CRH event,this study proposed a novel method to determine the maximum time interval for CRH events through the change in CRH event frequency with increasing time interval between individual events,using southern China as a case study.The results show that the threshold identified by the proposed method is reasonable.For more than 90%of the meteorological stations,the frequency of CRH events has reached a maximum when the time interval is less than or equal to the threshold.This study can aid in time interval selection,which is an important step for subsequent study of CRH events. 展开更多
关键词 Compound extreme weather event Rainstorm and heatwave Southern China Threshold.time interval
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Identifying,exploring,and interpreting time series shapes in multivariate time intervals 被引量:2
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作者 Gota Shirato Natalia Andrienko Gennady Andrienko 《Visual Informatics》 EI 2023年第1期77-91,共15页
We introduce a concept of episode referring to a time interval in the development of a dynamic phenomenon that is characterized by multiple time-variant attributes.A data structure representing a single episode is a m... We introduce a concept of episode referring to a time interval in the development of a dynamic phenomenon that is characterized by multiple time-variant attributes.A data structure representing a single episode is a multivariate time series.To analyse collections of episodes,we propose an approach that is based on recognition of particular patterns in the temporal variation of the variables within episodes.Each episode is thus represented by a combination of patterns.Using this representation,we apply visual analytics techniques to fulfil a set of analysis tasks,such as investigation of the temporal distribution of the patterns,frequencies of transitions between the patterns in episode sequences,and co-occurrences of patterns of different variables within same episodes.We demonstrate our approach on two examples using real-world data,namely,dynamics of human mobility indicators during the COVID-19 pandemic and characteristics of football team movements during episodes of ball turnover. 展开更多
关键词 Temporal patterns Multivariate time series time intervals
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Mapping soil organic matter content using Sentinel-2 syntheticimages at different time intervals in Northeast China
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作者 Chong Luo Wenqi Zhang +1 位作者 Xinle Zhang Huanjun Liu 《International Journal of Digital Earth》 SCIE EI 2023年第1期1094-1107,共14页
Mapping soil organic matter(SOM)content has become an important application of digital soil mapping.In this study,we processed all Sentinel-2 images covering the bare-soil period(March to June)in Northeast China from ... Mapping soil organic matter(SOM)content has become an important application of digital soil mapping.In this study,we processed all Sentinel-2 images covering the bare-soil period(March to June)in Northeast China from 2019 to 2022 and integrated the observation results into synthetic materials with four defined time intervals(10,15,20,and 30 d).Then,we used synthetic images corresponding to different time periods to conduct SOM mapping and determine the optimal time interval and time period beforefinally assessing the impacts of adding environmental covariates.The results showed the following:(1)in SOM mapping,the highest accuracy was obtained using day-of-year(DOY)120 to 140 synthetic images with 20 d time intervals,as well as with different time intervals,ranked as follows:20 d>30 d>15 d>10 d;(2)when using synthetic images at different time intervals to predict SOM,the best time period for predicting SOM was always within May;and(3)adding environmental covariates effectively improved the SOM mapping performance,and the multiyear average temperature was the most important factor.In general,our results demonstrated the valuable potential of SOM mapping using multiyear synthetic imagery,thereby allowing detailed mapping of large areas of cultivated soil. 展开更多
关键词 Sentinel-2 environmental covariates baresoilperiod synthetic images different time intervals soilorganic matter
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The burden of upper motor neuron involvement is correlated with the bilateral limb involvement interval in patients with amyotrophic lateral sclerosis:a retrospective observational study
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作者 Jieying Wu Shan Ye +2 位作者 Xiangyi Liu Yingsheng Xu Dongsheng Fan 《Neural Regeneration Research》 SCIE CAS 2025年第5期1505-1512,共8页
Amyotrophic lateral sclerosis is a rare neurodegenerative disease characterized by the involvement of both upper and lower motor neurons.Early bilateral limb involvement significantly affects patients'daily lives ... Amyotrophic lateral sclerosis is a rare neurodegenerative disease characterized by the involvement of both upper and lower motor neurons.Early bilateral limb involvement significantly affects patients'daily lives and may lead them to be confined to bed.However,the effect of upper and lower motor neuron impairment and other risk factors on bilateral limb involvement is unclear.To address this issue,we retrospectively collected data from 586 amyotrophic lateral sclerosis patients with limb onset diagnosed at Peking University Third Hospital between January 2020 and May 2022.A univariate analysis revealed no significant differences in the time intervals of spread in different directions between individuals with upper motor neuron-dominant amyotrophic lateral sclerosis and those with classic amyotrophic lateral sclerosis.We used causal directed acyclic graphs for risk factor determination and Cox proportional hazards models to investigate the association between the duration of bilateral limb involvement and clinical baseline characteristics in amyotrophic lateral sclerosis patients.Multiple factor analyses revealed that higher upper motor neuron scores(hazard ratio[HR]=1.05,95%confidence interval[CI]=1.01–1.09,P=0.018),onset in the left limb(HR=0.72,95%CI=0.58–0.89,P=0.002),and a horizontal pattern of progression(HR=0.46,95%CI=0.37–0.58,P<0.001)were risk factors for a shorter interval until bilateral limb involvement.The results demonstrated that a greater degree of upper motor neuron involvement might cause contralateral limb involvement to progress more quickly in limb-onset amyotrophic lateral sclerosis patients.These findings may improve the management of amyotrophic lateral sclerosis patients with limb onset and the prediction of patient prognosis. 展开更多
关键词 amyotrophic lateral sclerosis bilateral limb involvement Cox proportional hazards regression model horizontal spread restricted cubic spline analysis time interval upper motor neuron vertical spread
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Adaptive path planning for unmanned aerial vehicles based on bi-level programming and variable planning time interval 被引量:7
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作者 Liu Wei Zheng Zheng Cai Kaiyuan 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2013年第3期646-660,共15页
This paper presents an adaptive path planner for unmanned aerial vehicles (UAVs) to adapt a real-time path search procedure to variations and fluctuations of UAVs’ relevant performances, with respect to sensory cap... This paper presents an adaptive path planner for unmanned aerial vehicles (UAVs) to adapt a real-time path search procedure to variations and fluctuations of UAVs’ relevant performances, with respect to sensory capability, maneuverability, and flight velocity limit. On the basis of a novel adaptability-involved problem statement, bi-level programming (BLP) and variable planning step techniques are introduced to model the necessary path planning components and then an adaptive path planner is developed for the purpose of adaptation and optimization. Additionally, both probabilistic-risk-based obstacle avoidance and performance limits are described as path search constraints to guarantee path safety and navigability. A discrete-search-based path planning solution, embedded with four optimization strategies, is especially designed for the planner to efficiently generate optimal flight paths in complex operational spaces, within which different surface-to-air missiles (SAMs) are deployed. Simulation results in challenging and stochastic scenarios firstly demonstrate the effectiveness and efficiency of the proposed planner, and then verify its great adaptability and relative stability when planning optimal paths for a UAV with changing or fluctuating performances. 展开更多
关键词 ADAPTIVE Bi-level programming Motion planning Unmanned aerial vehicles Variable time interval
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Climate warming shifts the time interval between flowering and leaf unfolding depending on the warming period 被引量:3
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作者 Shuxin Wang Zhaofei Wu +5 位作者 Yufeng Gong Shubiao Wang Wei Zhang Shanshan Zhang Hans J.De Boeck Yongshuo H.Fu 《Science China(Life Sciences)》 SCIE CAS CSCD 2022年第11期2316-2324,共9页
The timing of flowering(FL)and leaf unfolding(LU)determine plants’reproduction and vegetative growth.Global warming has substantially advanced FL and LU of temperate and boreal plants,but their responses to warming d... The timing of flowering(FL)and leaf unfolding(LU)determine plants’reproduction and vegetative growth.Global warming has substantially advanced FL and LU of temperate and boreal plants,but their responses to warming differ,which may influence the time interval between FL and LU(ΔLU-FL),thereby impacting plant fitness and intraspecific physiological processes.Based on twigs collected from two flowering-first tree species,Populus tomentosa and Amygdalus triloba,we conducted a manipulative experiment to investigate the effects of winter chilling,spring warming and photoperiod on theΔLU-FL.We found that photoperiod did not affect theΔLU-FL of Amygdalus triloba,but shortenedΔLU-FL by 5.1 d of Populus tomentosa.Interestingly,spring warming and winter chilling oppositely affected theΔLU-FL of both species.Specifically,low chilling accumulation extended theΔLU-FL by 3.8 and 9.4 d for Populus tomentosa and Amygdalus triloba,but spring warming shortened theΔLU-FL by 4.1 and 0.2 d℃^(-1).Our results indicate that climate warming will decrease or increase theΔLU-FL depending on the warming periods,i.e.,spring or winter.The shifted time interval between flowering and leaf unfolding may have ecological effects including affecting pollen transfer efficiency and alter the structure and functioning of terrestrial ecosystem. 展开更多
关键词 CHILLING FLOWERING leaf unfolding PHOTOPERIOD spring phenology time interval warming period
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AN EXPLICIT COMPLETE SQUARE CONSERVATIVE SCHEME WITH ADJUSTABLE TIME INTERVALS
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作者 王斌 季仲贞 《Acta meteorologica Sinica》 SCIE 1994年第4期403-409,共7页
In this paper,a kind of explicit difference scheme to solve nonlinear evolution equations,perfectly keeping the square conservation by adjusting the time step interval,is constructed,from the comprehensive maintenance... In this paper,a kind of explicit difference scheme to solve nonlinear evolution equations,perfectly keeping the square conservation by adjusting the time step interval,is constructed,from the comprehensive maintenance of the ad- vantages of the implicit complete square conservative scheme and the explicit instantaneous square conservative scheme. The new schemes are based on the thought of adding a small dissipation,but it is different from the small dissipation method.The dissipative term used in the new schemes is not a simple artificial dissipative term,but a so-called (time) harmonious dissipative term that can compensate for the truncation errors from the dissociation of the time differential term.Therefore,the new schemes may have a high time precision and may acquire a satisfactory effect in numerical tests. 展开更多
关键词 adjustable time interval explicit scheme square conservation harmonious dissipation
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General time interval multidimensional BSDEs with generators satisfying a weak stochastic-monotonicity condition
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作者 Tingting Li Ziheng Xu Shengjun Fan 《Probability, Uncertainty and Quantitative Risk》 2021年第4期301-318,共18页
This paper establishes an existence and uniqueness result for the adapted solution of a general time interval multidimensional backward stochastic differential equation (BSDE), where the generator g satisfies a weak s... This paper establishes an existence and uniqueness result for the adapted solution of a general time interval multidimensional backward stochastic differential equation (BSDE), where the generator g satisfies a weak stochastic-monotonicity condition and a general growth condition in the state variable y, and a stochastic-Lipschitz condition in the state variable z. This unifies and strengthens some known works. In order to prove this result, we develop some ideas and techniques employed in Xiao and Fan [25] and Liu et al. [15]. In particular, we put forward and prove a stochastic Gronwall-type inequality and a stochastic Bihari-type inequality, which generalize the classical ones and may be useful in other applications. The martingale representation theorem, Itô’s formula, and the BMO martingale tool are used to prove these two inequalities. 展开更多
关键词 Backward stochastic differential equation General time interval Weak stochastic-monotonicity condition Existence and uniqueness Stochastic Gronwall-type inequality Stochastic Bihari-type inequality
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Deterministic and complete hyperentangled Bell states analysis assisted by frequency and time interval degrees of freedom
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作者 Xin-Jie Zhou Wen-Qiang Liu +2 位作者 Hai-Rui Wei Yan-Bei Zheng Fang-Fang Du 《Frontiers of physics》 SCIE CSCD 2022年第5期149-157,共9页
Hyperentangled Bell states analysis(HBSA)is an essential building block for certain hyper-parallel quantum information processing.We propose a complete and deterministic HBSA scheme encoded in spatial and polarization... Hyperentangled Bell states analysis(HBSA)is an essential building block for certain hyper-parallel quantum information processing.We propose a complete and deterministic HBSA scheme encoded in spatial and polarization degrees of freedom(DOFs)of two-photon system assisted by a fixed frequency-based entanglement and a time interval DOF.The parity information the spatial-based and polarization-based hyper-entanglement can be distinguished by the distinct time intervals of the photon pairs,and the phase information can be distinguished by the detection signature.Compared with previous schemes,the number of the auxiliary entanglements is reduced from two to one by introducing time interval DOF.Moreover,the additional frequency and time interval DOFs suffer less from the collective channel noise. 展开更多
关键词 hyperentangled Bell states analysis multiple degrees of freedom time interval
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An On-Line Modeling Based Kalman Filtering Process for Time-Interval-Variable Sequences with Application to Astronomic Surveying
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作者 韩建国 孙才红 李彦琴 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2003年第2期52-56,共5页
The problem of variable sampling time interval which appears in application of Kalman Filtering is analyzed and the corresponding filtering process with or without present transition matrix is suggested, then an appli... The problem of variable sampling time interval which appears in application of Kalman Filtering is analyzed and the corresponding filtering process with or without present transition matrix is suggested, then an application experiment for astronomical surveying is introduced. In this process, the known stochastically variable sampling time intervals play the roles as deterministic input sequences of the state-space description, and the corresponding matrix and (if needed) state transition matrix can be established by performing real-time and structure-linear system identification. 展开更多
关键词 Kalman filtering Variable sampling time interval Real-time and structure-linear system identification.
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Static softening behaviors of 7055 alloy during the interval time of multi-pass hot compression 被引量:6
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作者 Liang-Ming Yan Jian Shen +1 位作者 Jun-Peng Li Bai-Ping Mao 《Rare Metals》 SCIE EI CAS CSCD 2013年第3期241-246,共6页
Multipass plain strain compression test of 7055 alloy was carried out on Gleeble 1500D thermomechanical simulator to study the effect of interval time on static softening behavior between two passes. Microstructural f... Multipass plain strain compression test of 7055 alloy was carried out on Gleeble 1500D thermomechanical simulator to study the effect of interval time on static softening behavior between two passes. Microstructural features of the alloy deformed with delay times varying from 0 to 180 s after achieving a reduction of ,-~52 % in the 13 stages was investigated through TEM and EBSD observations. The 14th pass of peak stresses after different delay times were gained. The peak stress decreases with the interstage delay time increasing, but the decreasing trend is gradually slower. Static recovery, metadynamic recrystallization, and/or static recrystallization can be found in the alloy during two passes. The recovery and recrystallization degree increases with longer interstage delay time. The static recovery is the main softening mechanism. Subgrain coalescence and subgrain growth together with particle-stimulated nucleation are the main nucleation mechanisms for static recrystallization. 展开更多
关键词 7055 aluminum alloy Hot compression Microstructure interval time
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Enhancing Task Assignment in Crowdsensing Systems Based on Sensing Intervals and Location
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作者 Rasha Sleem Nagham Mekky +3 位作者 Shaker El-Sappagh Louai Alarabi Noha AHikal Mohammed Elmogy 《Computers, Materials & Continua》 SCIE EI 2022年第6期5619-5638,共20页
The popularity of mobile devices with sensors is captivating the attention of researchers to modern techniques,such as the internet of things(IoT)and mobile crowdsensing(MCS).The core concept behind MCS is to use the ... The popularity of mobile devices with sensors is captivating the attention of researchers to modern techniques,such as the internet of things(IoT)and mobile crowdsensing(MCS).The core concept behind MCS is to use the power of mobile sensors to accomplish a difficult task collaboratively,with each mobile user completing much simpler micro-tasks.This paper discusses the task assignment problem in mobile crowdsensing,which is dependent on sensing time and path planning with the constraints of participant travel distance budgets and sensing time intervals.The goal is to minimize aggregate sensing time for mobile users,which reduces energy consumption to encourage more participants to engage in sensing activities and maximize total task quality.This paper introduces a two-phase task assignment framework called location time-based algorithm(LTBA).LTBA is a framework that enhances task assignment in MCS,whereas assigning tasks requires overlapping time intervals between tasks and mobile users’tasks and the location of tasks and mobile users’paths.The process of assigning the nearest task to the mobile user’s current path depends on the ant colony optimization algorithm(ACO)and Euclidean distance.LTBA combines two algorithms:(1)greedy online allocation algorithm and(2)bio-inspired traveldistance-balance-based algorithm(B-DBA).The greedy algorithm was sensing time interval-based and worked on reducing the overall sensing time of the mobile user.B-DBA was location-based and worked on maximizing total task quality.The results demonstrate that the average task quality is 0.8158,0.7093,and 0.7733 for LTBA,B-DBA,and greedy,respectively.The sensing time was reduced to 644,1782,and 685 time units for LTBA,B-DBA,and greedy,respectively.Combining the algorithms improves task assignment in MCS for both total task quality and sensing time.The results demonstrate that combining the two algorithms in LTBA is the best performance for total task quality and total sensing time,and the greedy algorithm follows it then B-DBA. 展开更多
关键词 Mobile crowdsensing online task assignment participatory sensing path planning sensing time intervals ant colony optimization
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