An evaluation approach for the response time probability distribution of workflows based on the fluid stochastic Petri net formalism is presented. Firstly, some problems about stochastic workflow net modeling are disc...An evaluation approach for the response time probability distribution of workflows based on the fluid stochastic Petri net formalism is presented. Firstly, some problems about stochastic workflow net modeling are discussed. Then how to convert a stochastic workflow net model into a fluid stochastic Petri net model is described. The response time distribution can be obtained directly upon the transient state solution of the fluid stochastic Petri net model. In the proposed approach, there are not any restrictions on the structure of workflow models, and the processing times of workflow tasks can be modeled by using arbitrary probability distributions. Large workflow models can be efficiently tackled by recursively using a net reduction technique.展开更多
The Fork-Join program consisting of K parallel tasks is a useful model for a large number of computing applications. When the parallel processor has multi-channels, later tasks may finish execution earlier than their ...The Fork-Join program consisting of K parallel tasks is a useful model for a large number of computing applications. When the parallel processor has multi-channels, later tasks may finish execution earlier than their earlier tasks and may join with tasks from other programs. This phenomenon is called exchangeable join (EJ), which introduces correlation to the task’s service time. In this work, we investigate the response time of multiprocessor systems with EJ with a new approach. We analyze two aspects of this kind of systems: exchangeable join (EJ) and the capacity constraint (CC). We prove that the system response time can be effectively reduced by EJ, while the reduced amount is constrained by the capacity of the multiprocessor. An upper bound model is constructed based on this analysis and a quick estimation algorithm is proposed. The approximation formula is verified by extensive simulation results, which show that the relative error of approximation is less than 5%.展开更多
Magnetic fluid is a kind of functional composite material with nanosized structure and unique optical properties. The tunable magneto-optic modulation of magnetic fluid under external magnetic field, achieved by adjus...Magnetic fluid is a kind of functional composite material with nanosized structure and unique optical properties. The tunable magneto-optic modulation of magnetic fluid under external magnetic field, achieved by adjusting the polarization direction of incident light, is investigated theoretically and experimentally in this work. The corresponding modulation depth and response time are obtained. The accompanying mechanisms are clarified by using the theory of dichroism of magtietic fluid and the aggregation/disintegration processes of magnetic particles within magnetic fluid when the external magnetic field turns on/off.展开更多
Background:Concussed patients have impaired reaction time(RT)and cognition following injury that may linger and impair driving performance.Limited research has used direct methods to assess driving-RT post-concussion....Background:Concussed patients have impaired reaction time(RT)and cognition following injury that may linger and impair driving performance.Limited research has used direct methods to assess driving-RT post-concussion.Our study compared driving RT during simulated scenarios between concussed and control individuals and examined driving-RT’s relationship with traditional computerized neurocognitive testing(CNT)domains.Methods:We employed a cross-sectional study among 14 concussed(15.9±9.8 days post-concussion,mean±SD)individuals and 14 healthy controls matched for age,sex,and driving experience.Participants completed a driving simulator and CNT(CNS Vital Signs)assessment within 48 h of symptom resolution.A driving-RT composite(ms)was derived from 3 simulated driving scenarios:stoplight(green to yellow),evasion(avoiding approaching vehicle),and pedestrian(person running in front of vehicle).The CNT domains included verbal and visual memory;CNT-RT(simple-,complex-,Stroop-RT individually);simple and complex attention;motor,psychomotor,and processing speed;executive function;and cognitive flexibility.Independent t tests and Hedge d effect sizes assessed driving-RT differences between groups,Pearson correlations(r)examined driving RT and CNT domain relationships among cohorts separately,and p values were controlled for false discovery rate via Benjamini-Hochberg procedures(a=0.05).Results:Concussed participants demonstrated slower driving-RT composite scores than controls(mean difference=292.86 ms;95%confidence interval(95%CI):70.18515.54;p=0.023;d=0.992).Evasion-RT(p=0.054;d=0.806),pedestrian-RT(p=0.258;d=0.312),and stoplight-RT(p=0.292;d=0.585)outcomes were not statistically significant after false-discovery rate corrections but demonstrated medium to large effect sizes for concussed deficits.Among concussed individuals,driving-RT outcomes did not significantly correlate with CNT domains(r-range:0.51 to 0.55;p>0.05).No correlations existed between driving-RT outcomes and CNT domains among control participants either(r-range:0.52 to 0.72;p>0.05).Conclusion:Slowed driving-RT composite scores and large effect sizes among concussed individuals when asymptomatic signify lingering impairment and raise driving-safety concerns.Driving-RT and CNT-RT measures correlated moderately but not statistically,which indicates that CNT-RT is not an optimal surrogate for driving RT.展开更多
To measure and control the electron motion in atoms and molecules by the strong laser field on the attosecond time scale is one of the research frontiers of atomic and molecular photophysics. It involves many new phen...To measure and control the electron motion in atoms and molecules by the strong laser field on the attosecond time scale is one of the research frontiers of atomic and molecular photophysics. It involves many new phenomena and processes and raises a series of questions of concepts, theories, and methods. Recent studies show that the Coulomb potential can cause the ionization time lag(about 100 attoseconds) between instants of the field maximum and the ionization-rate maximum. This lag can be understood as the response time of the electronic wave function to the strong-field-induced ionization event. It has a profound influence on the subsequent ultrafast dynamics of the ionized electron and can significantly change the time–frequency properties of electron trajectory(an important theoretical tool for attosecond measurement). Here, the research progress of response time and its implications on attosecond measurement are briefly introduced.展开更多
Magneto-rhelological(MR)dampers are devices that employ rheological fluids to modify their mechanical properties.Their mechanical simplicity,high dynamic range,lower power requirements,large force capacity,robustness ...Magneto-rhelological(MR)dampers are devices that employ rheological fluids to modify their mechanical properties.Their mechanical simplicity,high dynamic range,lower power requirements,large force capacity,robustness and safe maimer of operation in cases of failure have made them attractive devices for semi-active real-time control in civil,aerospace and automotive applications.Time response characteristic is one of the most important technical performances of MR dampers,and response time directly affects the control frequency,application range and the actual effect of MR dampers.In this study,one kind of finite difference solution for predicting the response time ofmagneto-rheological dampers from"off-state"to"on-state"is put forward.A laminar flow model is used to describe the flow in the MR valve,and a bi-viscous fluid flow model is utilized to describe the relationship of shear stress and shear rate of MR fluid.An explicit difference format is used to diseretize the Novior-Stoks equation,and stability condition of this algorithm is built by Von-Neumann stability criterion.The pressure gradient along the flow duct is solved by a dichotomy algorithm with iteration,and the changing curve of the damping force versus time of MR damper is obtained as well.According to the abovementioned numerical algorithm,the damping forces versus time curves from"off-state"to"on-state"of a cylindrical piston type MR damper are computed.Moreover,the MR damper is installed in a material test system(MTS),the magnetic field in the wire circles of the MR damper is"triggered"when the MR damper is imposed to do a constant speed motion,and the damping force curves are recorded.The comparison between numerical results and experimental results indicates that this finite difference algorithm can be used to estimate the response time delay of MR dampers.展开更多
In this paper, the response time of all-optical AND logic gate using the triangular photonic crystal lattice is investigated. The proposed logic gate consists of a photonic crystal nano-resonator formed by changing th...In this paper, the response time of all-optical AND logic gate using the triangular photonic crystal lattice is investigated. The proposed logic gate consists of a photonic crystal nano-resonator formed by changing the size of the dielectric rods. The structure benefits the interference effect mechanism. The contrast ratio of the photonic crystal AND logic gate is obtained as 6 d B. In addition to simplicity, the designed nano-resonator increases the bit rate of logic gate. The delay time and footprint of logic gate are respectively 0.32 ps and 146 μm2. The proposed photonic crystal AND logic gate can operate at a bit rate of 3.12 Tbit/s。展开更多
The seismic design of gravity retaining walls is based mostly on the pseudo static method.The seismic earth pressure is assumed to be a constant without considering the wave traveling effect when the seismic wave prop...The seismic design of gravity retaining walls is based mostly on the pseudo static method.The seismic earth pressure is assumed to be a constant without considering the wave traveling effect when the seismic wave propagates through the slope.However,under continuous ground motion,the actual earth pressure on the retaining wall varies with time.The present seismic earth pressure calculation method yields results that differ significantly from the actual scenario.Considering this,a slip surface curve was assumed in this study.It is more suitable for engineering practice.In addition,a theoretical calculation model based on energy dissipation was established.The time history of seismic earth pressure response under continuous ground motion was calculated using the equilibrium equation between the external power and the internal energy dissipation power of the sliding soil wedge.It can more effectively reflect the stress scenario of a retaining wall under seismic conditions.To verify the applicability of the proposed approach,a large-scale shaking table test was conducted,and the time history of the seismic earth pressure response obtained from the experiment was compared with the calculation results.The results show that the proposed approach is applicable to the calculation of the time history of seismic earth pressure response of gravity retaining walls.This lays the foundation for the seismic design of retaining structures by using dynamic time history.展开更多
The study was designed to explore the potential applications of the real-time cell electronic analysis technology in the quality evaluation of natural medicines. The natural medicinal Flos Carthami was discussed as a ...The study was designed to explore the potential applications of the real-time cell electronic analysis technology in the quality evaluation of natural medicines. The natural medicinal Flos Carthami was discussed as a methodological example and the specific time/dose-dependent cell response profiles （TCRPs） were produced by the real-time cell electronic analysis technology. The similarity and bioactivity were obtained by analyzing all TCRPs. Meanwhile, an HPLC method according to the Chinese Pharmacopeia （edition 2010） was used to evaluate the quality of Flos Carthami. The correlation was obtained by comparing the results produced by the two different approaches. By analyzing the data, five different samples ofFlos Carthami can produce remarkably similar TCRPs. The quality ofFlos Carthami was evaluated by both the HPLC and the TCRPs analysis-based approaches and similar results were obtained. The results suggest that the same natural medicine from different locations could produce similar TCRPs. By analyzing the TCRPs, the bioactivity and quality evaluation of natural medicines can be obtained. This technology is a physiologically relevant approach for the quality evaluation of natural medicines. The ultimate aim of our study is to establish a new standard for quality evaluation.展开更多
Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral l...Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral limb. We used functional MRI to investigate whether motor performance of the untrained limb could be improved using a serial reaction time task according to motor sequential learning of the trained limb, and whether these skill acquisitions led to changes in brain activation patterns. We recruited 20 right-handed healthy subjects, who were randomly allocated into training and control groups. The training group was trained in performance of a serial reaction time task using their non-dominant left hand, 40 minutes per day, for 10 days, over a period of 2 weeks. The control group did not receive training. Measurements of response time and percentile of response accuracy were performed twice during pre- and post-training, while brain functional MRI was scanned during performance of the serial reaction time task using the untrained right hand. In the training group, prominent changes in response time and percentile of response accuracy were observed in both the untrained right hand and the trained left hand between pre- and post-training. The control group showed no significant changes in the untrained hand between pre- and post-training. In the training group, the activated volume of the cortical areas related to motor function （i.e., primary motor cortex, premotor area, posterior parietal cortex） showed a gradual decrease, and enhanced cerebellar activation of the vermis and the newly activated ipsilateral dentate nucleus were observed during performance of the serial reaction time task using the untrained right hand, accompanied by the cross-motor learning effect. However, no significant changes were observed in the control group. Our findings indicate that motor skills learned over the 2-week training using the trained limb were transferred to the opposite homologous limb, and motor skill acquisition of the untrained limb led to changes in brain activation patterns in the cerebral cortex and cerebellum.展开更多
In this paper the temperature dependence of responsivity and response time for 6H-SiC ultraviolet （UV） photodetector is simulated based on numerical model in the range from 300 K to 900 K. The simulation results sho...In this paper the temperature dependence of responsivity and response time for 6H-SiC ultraviolet （UV） photodetector is simulated based on numerical model in the range from 300 K to 900 K. The simulation results show that the responsivity and the response time of device are less sensitive to temperature and this kind of UV photodetector has excellent temperature stability. Also the effects of device structure and bias voltage on the responsivity and the response time are presented. The thicker the drift region is, the higher the responsivity and the longer the response time are. So the thickness of drift region has to be carefully designed to make trade-off between responsivity and response time.展开更多
Digital broadcasting system has become a high-light of research on computer application. To respond to the changes of the playbill in the broadcasting system in real time, the response time of the system must be studi...Digital broadcasting system has become a high-light of research on computer application. To respond to the changes of the playbill in the broadcasting system in real time, the response time of the system must be studied. There is scarcely the research on this area currently. The influence factors in the response time are analyzed; the model on the response time of the system service is built; how the influence factors affect the response time of the system service is validated; and four improvement measures are proposed to minimize the response time of system service.展开更多
CAPTCHA is an acronym that stands for Completely Automated Public Turing Test to tell Computers and Humans Apart(CAPTCHA),it is a good example of an authentication system that can be used to determine the true identit...CAPTCHA is an acronym that stands for Completely Automated Public Turing Test to tell Computers and Humans Apart(CAPTCHA),it is a good example of an authentication system that can be used to determine the true identity of any user.It serves as a security measure to prevent an attack caused by web bots(automatic programs)during an online transaction.It can come as text-based or image-based depending on the project and the programmer.The usability and robustness,as well as level of security,provided each of the varies and call for the development of an improved system.Hence,this paper studied and improved two different CAPTCHA systems(the text-based CAPTCHA and image-based CAPTCHA).The textbased and image-based CAPTCHAwere designed using JavaScript.Response time and solving time are the two metrics used to determine the effectiveness and efficiency of the two CAPTCHA systems.The inclusion of response time and solving time improved the shortfall of the usability and robustness of the existing system.The developed system was tested using 200 students from the Federal College of Animal Health and Production Technology.The results of each of the participants,for the two CAPTCHAs,were extracted from the database and subjected to analysis using SPSS.The result shows that textbased CAPTCHAhas the lowest average solving time(21.3333 s)with a 47.8%success rate while image-based CAPTCHA has the highest average solving time was 23.5138 s with a 52.8%success rate.The average response time for the image-based CAPTCHA was 2.1855 s with a 37.9%success rate lower than the text-based CAPTCHA response time(3.5561 s)with a 62.1%success rate.This indicates that the text-based CAPTCHA is more effective in terms of usability tests while image-based CAPTCHA is more efficient in terms of system responsiveness and recommended for potential users.展开更多
The behavior of variable transparency glass is studied, and the response time analyzed and measured aimed at applications to welding goggles. Detection apparatus for goggle testing is involved in the design and develo...The behavior of variable transparency glass is studied, and the response time analyzed and measured aimed at applications to welding goggles. Detection apparatus for goggle testing is involved in the design and development. Charac-teristics of the apparatus are discussed based on experiments. The definition of nominal response time and effective response time are presented based on the analysis and calculation with experimental data.展开更多
Emergency ambulance services in the UK are tasked with providing pre-hospital patient care and clinical services with a target response time between call connect to on-scene attendance.In 2017,NHS England introduced f...Emergency ambulance services in the UK are tasked with providing pre-hospital patient care and clinical services with a target response time between call connect to on-scene attendance.In 2017,NHS England introduced four new response time categories based on patient needs.The most challenging is to be on-scene for a life-threatening situation within seven minutes of the call being connected when such calls are random in terms of time and place throughout a large territory.Recent evidence indicates emergency ambulance services regularly fall short of achieving the target ambulance response times set by the National Health Service(NHS).To achieve these targets,they need to undertake transformational change and apply statistical,operations research and artificial intelligence techniques in the form of five separate modules covering demand forecasting,plus locate,allocate,dispatch,monitoring and re-deployment of resources.These modules should be linked in real-time employing a data warehouse to minimise computational data and generate accurate,meaningful and timely decisions ensuring patients receive an appropriate and timely response.A simulation covering a limited geographical area,time and operational data concluded that this form of integration of the five modules provides accurate and timely data upon which to make decisions that effectively improve ambulance response times.展开更多
When gas invasion,especially overflow,occurs at the bottom hole in the process of managed pressure drilling(MPD),it is common to apply backpressure on the wellbore by adjusting the backpressure pump and throttle valve...When gas invasion,especially overflow,occurs at the bottom hole in the process of managed pressure drilling(MPD),it is common to apply backpressure on the wellbore by adjusting the backpressure pump and throttle valve,so as to rebuild bottom hole pressure balance.If it is still thought that the wellhead backpressure is loaded to the bottom hole instantaneously,there will be larger errors between the calculated wellbore parameters and the actual wellbore flow parameters,which will result in well control failure and even well blowout.In this paper,a pressure wave propagation equation suitable for the gaseliquid two-phase flow in the annulus was established based on the global averaged gaseliquid two-phase flow model to investigate the propagation velocity and time of backpressure wave in the wellbore.Then,gaseliquid interaction was introduced to carry out coupling solution on the equation set.It is shown that pressure wave velocity increases with the increase of drilling mud density,but decreases with the increase of void fraction and virtual mass force coefficient.It changes drastically at first,and then slows down.What's more,when the void fraction is greater than 0.1 or the virtual mass force coefficient exceeds 0.2,the momentum between gas phase and liquid phase is fully exchanged,and the pressure wave velocity decreases slowly,approaching a stable value.In Well Penglai 9 in the Sichuan Basin,for example,the average time of single pressure wave propagation is about 50 s,and the total propagation time of 4 rounds is about 200 s,which accounts for more than 67%of the total time of system control response.It is indicated that the propagation velocity and time of the pressure wave in the annulus calculated by this method can greatly improve the accuracy of managed pressure response time of MPD drilling system and the control precision of adaptive throttle valve.展开更多
In 2005 year, SWIP carded through a general engineering and physics experiment of ECRH on HL-2A tokamak. The ECRH protection system is studied and set up to insure the security of ECRH system, and the work is normal. ...In 2005 year, SWIP carded through a general engineering and physics experiment of ECRH on HL-2A tokamak. The ECRH protection system is studied and set up to insure the security of ECRH system, and the work is normal. The main protection object of all ECRH system is the gyrotron, and the arc protection for it is more important in the protection system.展开更多
The source region of the Yellow River(SRYR),with its semi-humid to semi-arid climate,is crucial for understanding water resource dynamics.Precipitation is key for replenishing surface water and balancing the ecosystem...The source region of the Yellow River(SRYR),with its semi-humid to semi-arid climate,is crucial for understanding water resource dynamics.Precipitation is key for replenishing surface water and balancing the ecosystem’s water cycle.However,the soil moisture response to precipitation across climate zones and soil layers remains poorly understood due to limited long-term data.This study examines the response of soil moisture to precipitation at multiple time scales in the SRYR,using data from Maqu,Mado,Ngoring Lake sites,and the Maqu monitoring network(MMN),along with CN05.1 precipitation and GLEAM v3.8a soil moisture data.Results show that the semi-humid area requires more precipitation to trigger soil moisture responses compared to the semi-arid area in the SRYR.Surface soil at Maqu,MMN,Ngoring Lake,and Mado sites require at least 8.6,8.4,5.2,and 2.84 mm of precipitation,respectively,for effective replenishment.Significant responses to precipitation events were observed in soil layers at 40 cm and above in the semi-humid area,while at 20 cm and above in the semi-arid area.Precipitation volume is the primary factor influencing soil moisture,affecting both the increment and time lag to maximum moisture.Precipitation intensity and pre-rain moisture have no direct effect.In the central SRYR,accumulated precipitation has a greater impact.Root-zone soil moisture has a weaker correlation with precipitation compared to surface soil moisture but persists longer,responding for up to 10 days,while surface soil moisture responds more immediately but only lasts about 5 days.展开更多
Emergency medical services (EMS) are a vital element of the public healthcare system in China,^([1])providing an opportunity to respond to critical medical conditions and save people’s lives.^([2])The accessibility o...Emergency medical services (EMS) are a vital element of the public healthcare system in China,^([1])providing an opportunity to respond to critical medical conditions and save people’s lives.^([2])The accessibility of EMS has received considerable attention in health and transport geography studies.^([3])One of the optimal gauges for evaluating the accessibility of EMS is the response time,which is defined as the time from receiving an emergency call to the arrival of an ambulance.^([4])Beijing has already reduced the response time to approximately12 min,and the next goal is to ensure that the response time across Beijing does not exceed 12 min (the information comes from the Beijing Emergency Medical Center).展开更多
This review comprehensively explores the theory and applications of attosecond transient absorption spectroscopy(ATAS)in studying ultrafast electronic dynamics across various systems,from atoms to solids.Driven by sig...This review comprehensively explores the theory and applications of attosecond transient absorption spectroscopy(ATAS)in studying ultrafast electronic dynamics across various systems,from atoms to solids.Driven by significant advancements in ultrafast laser technology,such as generating isolated attosecond pulses,ATAS enables detailed investigations of ultrafast electronic processes with unprecedented time resolution.The article introduces the fundamental principles and historical development of ATAS.Applications of ATAS are discussed in three main domains:in atoms,where it has been used to study build-up dynamics of Autler–Townes splitting,Fano resonance,light-induced states,etc.;in molecules,where it has revealed coherent molecular wavepacket dynamics and non-adiabatic dynamics near conical intersections;and in solids,where it has been extended to investigate ultrafast charge carrier dynamics in metals,semiconductors,and insulators.The review highlights the potential of ATAS in developing ultrafast optical switches and petahertz electronics.The ability of ATAS to probe and manipulate electronic dynamics at the attosecond timescale provides a powerful tool for exploring the fundamental limits of electronic and optical processes in materials.展开更多
基金The National Natural Science Foundation of China(No.60175027).
文摘An evaluation approach for the response time probability distribution of workflows based on the fluid stochastic Petri net formalism is presented. Firstly, some problems about stochastic workflow net modeling are discussed. Then how to convert a stochastic workflow net model into a fluid stochastic Petri net model is described. The response time distribution can be obtained directly upon the transient state solution of the fluid stochastic Petri net model. In the proposed approach, there are not any restrictions on the structure of workflow models, and the processing times of workflow tasks can be modeled by using arbitrary probability distributions. Large workflow models can be efficiently tackled by recursively using a net reduction technique.
基金Project supported by the National Natural Science Foundation of0 China (Nos. 60274011 and 60574067), and the Program for NewCentury Excellent Talents in University (No. NCET-04-0094), China
文摘The Fork-Join program consisting of K parallel tasks is a useful model for a large number of computing applications. When the parallel processor has multi-channels, later tasks may finish execution earlier than their earlier tasks and may join with tasks from other programs. This phenomenon is called exchangeable join (EJ), which introduces correlation to the task’s service time. In this work, we investigate the response time of multiprocessor systems with EJ with a new approach. We analyze two aspects of this kind of systems: exchangeable join (EJ) and the capacity constraint (CC). We prove that the system response time can be effectively reduced by EJ, while the reduced amount is constrained by the capacity of the multiprocessor. An upper bound model is constructed based on this analysis and a quick estimation algorithm is proposed. The approximation formula is verified by extensive simulation results, which show that the relative error of approximation is less than 5%.
基金supported by the National Natural Science Foundation of China (Grant No. 10704048)the Innovation Program of Shanghai Municipal Education Commission, China (Grant No. 11YZ120)the Innovation Fund Project for Graduate Student of Shanghai, China (Grant No. JWCXSL1022)
文摘Magnetic fluid is a kind of functional composite material with nanosized structure and unique optical properties. The tunable magneto-optic modulation of magnetic fluid under external magnetic field, achieved by adjusting the polarization direction of incident light, is investigated theoretically and experimentally in this work. The corresponding modulation depth and response time are obtained. The accompanying mechanisms are clarified by using the theory of dichroism of magtietic fluid and the aggregation/disintegration processes of magnetic particles within magnetic fluid when the external magnetic field turns on/off.
基金the Office of the Vice President of Research at the University of Georgia.
文摘Background:Concussed patients have impaired reaction time(RT)and cognition following injury that may linger and impair driving performance.Limited research has used direct methods to assess driving-RT post-concussion.Our study compared driving RT during simulated scenarios between concussed and control individuals and examined driving-RT’s relationship with traditional computerized neurocognitive testing(CNT)domains.Methods:We employed a cross-sectional study among 14 concussed(15.9±9.8 days post-concussion,mean±SD)individuals and 14 healthy controls matched for age,sex,and driving experience.Participants completed a driving simulator and CNT(CNS Vital Signs)assessment within 48 h of symptom resolution.A driving-RT composite(ms)was derived from 3 simulated driving scenarios:stoplight(green to yellow),evasion(avoiding approaching vehicle),and pedestrian(person running in front of vehicle).The CNT domains included verbal and visual memory;CNT-RT(simple-,complex-,Stroop-RT individually);simple and complex attention;motor,psychomotor,and processing speed;executive function;and cognitive flexibility.Independent t tests and Hedge d effect sizes assessed driving-RT differences between groups,Pearson correlations(r)examined driving RT and CNT domain relationships among cohorts separately,and p values were controlled for false discovery rate via Benjamini-Hochberg procedures(a=0.05).Results:Concussed participants demonstrated slower driving-RT composite scores than controls(mean difference=292.86 ms;95%confidence interval(95%CI):70.18515.54;p=0.023;d=0.992).Evasion-RT(p=0.054;d=0.806),pedestrian-RT(p=0.258;d=0.312),and stoplight-RT(p=0.292;d=0.585)outcomes were not statistically significant after false-discovery rate corrections but demonstrated medium to large effect sizes for concussed deficits.Among concussed individuals,driving-RT outcomes did not significantly correlate with CNT domains(r-range:0.51 to 0.55;p>0.05).No correlations existed between driving-RT outcomes and CNT domains among control participants either(r-range:0.52 to 0.72;p>0.05).Conclusion:Slowed driving-RT composite scores and large effect sizes among concussed individuals when asymptomatic signify lingering impairment and raise driving-safety concerns.Driving-RT and CNT-RT measures correlated moderately but not statistically,which indicates that CNT-RT is not an optimal surrogate for driving RT.
基金Project supported by the National Natural Science Foundation of China(Grant No.91750111)the National Key Research and Development Program of China(Grant No.2018YFB0504400)。
文摘To measure and control the electron motion in atoms and molecules by the strong laser field on the attosecond time scale is one of the research frontiers of atomic and molecular photophysics. It involves many new phenomena and processes and raises a series of questions of concepts, theories, and methods. Recent studies show that the Coulomb potential can cause the ionization time lag(about 100 attoseconds) between instants of the field maximum and the ionization-rate maximum. This lag can be understood as the response time of the electronic wave function to the strong-field-induced ionization event. It has a profound influence on the subsequent ultrafast dynamics of the ionized electron and can significantly change the time–frequency properties of electron trajectory(an important theoretical tool for attosecond measurement). Here, the research progress of response time and its implications on attosecond measurement are briefly introduced.
基金supported by National Natural Science Foundation of China(Grant No.50675106)
文摘Magneto-rhelological(MR)dampers are devices that employ rheological fluids to modify their mechanical properties.Their mechanical simplicity,high dynamic range,lower power requirements,large force capacity,robustness and safe maimer of operation in cases of failure have made them attractive devices for semi-active real-time control in civil,aerospace and automotive applications.Time response characteristic is one of the most important technical performances of MR dampers,and response time directly affects the control frequency,application range and the actual effect of MR dampers.In this study,one kind of finite difference solution for predicting the response time ofmagneto-rheological dampers from"off-state"to"on-state"is put forward.A laminar flow model is used to describe the flow in the MR valve,and a bi-viscous fluid flow model is utilized to describe the relationship of shear stress and shear rate of MR fluid.An explicit difference format is used to diseretize the Novior-Stoks equation,and stability condition of this algorithm is built by Von-Neumann stability criterion.The pressure gradient along the flow duct is solved by a dichotomy algorithm with iteration,and the changing curve of the damping force versus time of MR damper is obtained as well.According to the abovementioned numerical algorithm,the damping forces versus time curves from"off-state"to"on-state"of a cylindrical piston type MR damper are computed.Moreover,the MR damper is installed in a material test system(MTS),the magnetic field in the wire circles of the MR damper is"triggered"when the MR damper is imposed to do a constant speed motion,and the damping force curves are recorded.The comparison between numerical results and experimental results indicates that this finite difference algorithm can be used to estimate the response time delay of MR dampers.
文摘In this paper, the response time of all-optical AND logic gate using the triangular photonic crystal lattice is investigated. The proposed logic gate consists of a photonic crystal nano-resonator formed by changing the size of the dielectric rods. The structure benefits the interference effect mechanism. The contrast ratio of the photonic crystal AND logic gate is obtained as 6 d B. In addition to simplicity, the designed nano-resonator increases the bit rate of logic gate. The delay time and footprint of logic gate are respectively 0.32 ps and 146 μm2. The proposed photonic crystal AND logic gate can operate at a bit rate of 3.12 Tbit/s。
基金supported by the Strategic International Science and Technology Innovation Cooperation Project‘Research on On-line Monitoring and Evaluation Technology of Safety Status of Highspeed Railway Track-subgrade System’from the National Key R&D Program of China(Grant No.2018YFE0207100)the State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining&Technology/China University of Mining&Technology,Beijing(Grant No.SKLGDUEK1910)+1 种基金the Foundation of Engineering Research Center of Eco-environment in the Three Gorges Reservoir Region of China(Grant No.KF2018-01)the Youth Scientific and Technological Innovation Team of Southwest Petroleum University(Grant No.2018CXTD02)。
文摘The seismic design of gravity retaining walls is based mostly on the pseudo static method.The seismic earth pressure is assumed to be a constant without considering the wave traveling effect when the seismic wave propagates through the slope.However,under continuous ground motion,the actual earth pressure on the retaining wall varies with time.The present seismic earth pressure calculation method yields results that differ significantly from the actual scenario.Considering this,a slip surface curve was assumed in this study.It is more suitable for engineering practice.In addition,a theoretical calculation model based on energy dissipation was established.The time history of seismic earth pressure response under continuous ground motion was calculated using the equilibrium equation between the external power and the internal energy dissipation power of the sliding soil wedge.It can more effectively reflect the stress scenario of a retaining wall under seismic conditions.To verify the applicability of the proposed approach,a large-scale shaking table test was conducted,and the time history of the seismic earth pressure response obtained from the experiment was compared with the calculation results.The results show that the proposed approach is applicable to the calculation of the time history of seismic earth pressure response of gravity retaining walls.This lays the foundation for the seismic design of retaining structures by using dynamic time history.
基金financially supported by a Cultivated Project from Nanjing university of Chinese medicine (No. 10XPY01)the National Natural Science Foundation of China (No. 81202922)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, PAPD (No. 2011ZYX3-004)
文摘The study was designed to explore the potential applications of the real-time cell electronic analysis technology in the quality evaluation of natural medicines. The natural medicinal Flos Carthami was discussed as a methodological example and the specific time/dose-dependent cell response profiles （TCRPs） were produced by the real-time cell electronic analysis technology. The similarity and bioactivity were obtained by analyzing all TCRPs. Meanwhile, an HPLC method according to the Chinese Pharmacopeia （edition 2010） was used to evaluate the quality of Flos Carthami. The correlation was obtained by comparing the results produced by the two different approaches. By analyzing the data, five different samples ofFlos Carthami can produce remarkably similar TCRPs. The quality ofFlos Carthami was evaluated by both the HPLC and the TCRPs analysis-based approaches and similar results were obtained. The results suggest that the same natural medicine from different locations could produce similar TCRPs. By analyzing the TCRPs, the bioactivity and quality evaluation of natural medicines can be obtained. This technology is a physiologically relevant approach for the quality evaluation of natural medicines. The ultimate aim of our study is to establish a new standard for quality evaluation.
基金supported by the Yeungnam College of Science & Technology Research Grants in 2012
文摘Cross-training is a phenomenon related to motor learning, where motor performance of the untrained limb shows improvement in strength and skill execution following unilateral training of the homologous contralateral limb. We used functional MRI to investigate whether motor performance of the untrained limb could be improved using a serial reaction time task according to motor sequential learning of the trained limb, and whether these skill acquisitions led to changes in brain activation patterns. We recruited 20 right-handed healthy subjects, who were randomly allocated into training and control groups. The training group was trained in performance of a serial reaction time task using their non-dominant left hand, 40 minutes per day, for 10 days, over a period of 2 weeks. The control group did not receive training. Measurements of response time and percentile of response accuracy were performed twice during pre- and post-training, while brain functional MRI was scanned during performance of the serial reaction time task using the untrained right hand. In the training group, prominent changes in response time and percentile of response accuracy were observed in both the untrained right hand and the trained left hand between pre- and post-training. The control group showed no significant changes in the untrained hand between pre- and post-training. In the training group, the activated volume of the cortical areas related to motor function （i.e., primary motor cortex, premotor area, posterior parietal cortex） showed a gradual decrease, and enhanced cerebellar activation of the vermis and the newly activated ipsilateral dentate nucleus were observed during performance of the serial reaction time task using the untrained right hand, accompanied by the cross-motor learning effect. However, no significant changes were observed in the control group. Our findings indicate that motor skills learned over the 2-week training using the trained limb were transferred to the opposite homologous limb, and motor skill acquisition of the untrained limb led to changes in brain activation patterns in the cerebral cortex and cerebellum.
文摘In this paper the temperature dependence of responsivity and response time for 6H-SiC ultraviolet （UV） photodetector is simulated based on numerical model in the range from 300 K to 900 K. The simulation results show that the responsivity and the response time of device are less sensitive to temperature and this kind of UV photodetector has excellent temperature stability. Also the effects of device structure and bias voltage on the responsivity and the response time are presented. The thicker the drift region is, the higher the responsivity and the longer the response time are. So the thickness of drift region has to be carefully designed to make trade-off between responsivity and response time.
文摘Digital broadcasting system has become a high-light of research on computer application. To respond to the changes of the playbill in the broadcasting system in real time, the response time of the system must be studied. There is scarcely the research on this area currently. The influence factors in the response time are analyzed; the model on the response time of the system service is built; how the influence factors affect the response time of the system service is validated; and four improvement measures are proposed to minimize the response time of system service.
文摘CAPTCHA is an acronym that stands for Completely Automated Public Turing Test to tell Computers and Humans Apart(CAPTCHA),it is a good example of an authentication system that can be used to determine the true identity of any user.It serves as a security measure to prevent an attack caused by web bots(automatic programs)during an online transaction.It can come as text-based or image-based depending on the project and the programmer.The usability and robustness,as well as level of security,provided each of the varies and call for the development of an improved system.Hence,this paper studied and improved two different CAPTCHA systems(the text-based CAPTCHA and image-based CAPTCHA).The textbased and image-based CAPTCHAwere designed using JavaScript.Response time and solving time are the two metrics used to determine the effectiveness and efficiency of the two CAPTCHA systems.The inclusion of response time and solving time improved the shortfall of the usability and robustness of the existing system.The developed system was tested using 200 students from the Federal College of Animal Health and Production Technology.The results of each of the participants,for the two CAPTCHAs,were extracted from the database and subjected to analysis using SPSS.The result shows that textbased CAPTCHAhas the lowest average solving time(21.3333 s)with a 47.8%success rate while image-based CAPTCHA has the highest average solving time was 23.5138 s with a 52.8%success rate.The average response time for the image-based CAPTCHA was 2.1855 s with a 37.9%success rate lower than the text-based CAPTCHA response time(3.5561 s)with a 62.1%success rate.This indicates that the text-based CAPTCHA is more effective in terms of usability tests while image-based CAPTCHA is more efficient in terms of system responsiveness and recommended for potential users.
基金the Science and Technology Commission of Shanghai Municipality (Grant No.052912015)
文摘The behavior of variable transparency glass is studied, and the response time analyzed and measured aimed at applications to welding goggles. Detection apparatus for goggle testing is involved in the design and development. Charac-teristics of the apparatus are discussed based on experiments. The definition of nominal response time and effective response time are presented based on the analysis and calculation with experimental data.
文摘Emergency ambulance services in the UK are tasked with providing pre-hospital patient care and clinical services with a target response time between call connect to on-scene attendance.In 2017,NHS England introduced four new response time categories based on patient needs.The most challenging is to be on-scene for a life-threatening situation within seven minutes of the call being connected when such calls are random in terms of time and place throughout a large territory.Recent evidence indicates emergency ambulance services regularly fall short of achieving the target ambulance response times set by the National Health Service(NHS).To achieve these targets,they need to undertake transformational change and apply statistical,operations research and artificial intelligence techniques in the form of five separate modules covering demand forecasting,plus locate,allocate,dispatch,monitoring and re-deployment of resources.These modules should be linked in real-time employing a data warehouse to minimise computational data and generate accurate,meaningful and timely decisions ensuring patients receive an appropriate and timely response.A simulation covering a limited geographical area,time and operational data concluded that this form of integration of the five modules provides accurate and timely data upon which to make decisions that effectively improve ambulance response times.
基金Project supported by General Program of National Natural Science Foundation of China“Wellbore Multi-phase Flow Coupling Mechanism Research-Formations Based on Precise Backpressure Control”(No.:51474073)“Research on Wellbore Temperature Field and Pressure Field Distribution Laws of Deep Unbalanced Drilling Based on Thermal-fluid Coupling”(No.:51374077).
文摘When gas invasion,especially overflow,occurs at the bottom hole in the process of managed pressure drilling(MPD),it is common to apply backpressure on the wellbore by adjusting the backpressure pump and throttle valve,so as to rebuild bottom hole pressure balance.If it is still thought that the wellhead backpressure is loaded to the bottom hole instantaneously,there will be larger errors between the calculated wellbore parameters and the actual wellbore flow parameters,which will result in well control failure and even well blowout.In this paper,a pressure wave propagation equation suitable for the gaseliquid two-phase flow in the annulus was established based on the global averaged gaseliquid two-phase flow model to investigate the propagation velocity and time of backpressure wave in the wellbore.Then,gaseliquid interaction was introduced to carry out coupling solution on the equation set.It is shown that pressure wave velocity increases with the increase of drilling mud density,but decreases with the increase of void fraction and virtual mass force coefficient.It changes drastically at first,and then slows down.What's more,when the void fraction is greater than 0.1 or the virtual mass force coefficient exceeds 0.2,the momentum between gas phase and liquid phase is fully exchanged,and the pressure wave velocity decreases slowly,approaching a stable value.In Well Penglai 9 in the Sichuan Basin,for example,the average time of single pressure wave propagation is about 50 s,and the total propagation time of 4 rounds is about 200 s,which accounts for more than 67%of the total time of system control response.It is indicated that the propagation velocity and time of the pressure wave in the annulus calculated by this method can greatly improve the accuracy of managed pressure response time of MPD drilling system and the control precision of adaptive throttle valve.
文摘In 2005 year, SWIP carded through a general engineering and physics experiment of ECRH on HL-2A tokamak. The ECRH protection system is studied and set up to insure the security of ECRH system, and the work is normal. The main protection object of all ECRH system is the gyrotron, and the arc protection for it is more important in the protection system.
基金supported by the National Natural Science Foundation of China(Grant No.42325502,and 42275045)the West Light Foundation of the Chi-nese Academy of Sciences(Grant No.xbzg-zdsys-202215)+1 种基金the Sci-ence and Technology Research Plan of Gansu Province(Grant Nos.23JRRA654 and 20JR10RA070)iLEAPs(Integrated Land Ecosystem-Atmosphere Processes Study).
文摘The source region of the Yellow River(SRYR),with its semi-humid to semi-arid climate,is crucial for understanding water resource dynamics.Precipitation is key for replenishing surface water and balancing the ecosystem’s water cycle.However,the soil moisture response to precipitation across climate zones and soil layers remains poorly understood due to limited long-term data.This study examines the response of soil moisture to precipitation at multiple time scales in the SRYR,using data from Maqu,Mado,Ngoring Lake sites,and the Maqu monitoring network(MMN),along with CN05.1 precipitation and GLEAM v3.8a soil moisture data.Results show that the semi-humid area requires more precipitation to trigger soil moisture responses compared to the semi-arid area in the SRYR.Surface soil at Maqu,MMN,Ngoring Lake,and Mado sites require at least 8.6,8.4,5.2,and 2.84 mm of precipitation,respectively,for effective replenishment.Significant responses to precipitation events were observed in soil layers at 40 cm and above in the semi-humid area,while at 20 cm and above in the semi-arid area.Precipitation volume is the primary factor influencing soil moisture,affecting both the increment and time lag to maximum moisture.Precipitation intensity and pre-rain moisture have no direct effect.In the central SRYR,accumulated precipitation has a greater impact.Root-zone soil moisture has a weaker correlation with precipitation compared to surface soil moisture but persists longer,responding for up to 10 days,while surface soil moisture responds more immediately but only lasts about 5 days.
基金supported by National Key Research & Development Program of China (2022YFC3006201)。
文摘Emergency medical services (EMS) are a vital element of the public healthcare system in China,^([1])providing an opportunity to respond to critical medical conditions and save people’s lives.^([2])The accessibility of EMS has received considerable attention in health and transport geography studies.^([3])One of the optimal gauges for evaluating the accessibility of EMS is the response time,which is defined as the time from receiving an emergency call to the arrival of an ambulance.^([4])Beijing has already reduced the response time to approximately12 min,and the next goal is to ensure that the response time across Beijing does not exceed 12 min (the information comes from the Beijing Emergency Medical Center).
基金Project supported by the National Natural Science Foundation of China(Grant No.12174034)。
文摘This review comprehensively explores the theory and applications of attosecond transient absorption spectroscopy(ATAS)in studying ultrafast electronic dynamics across various systems,from atoms to solids.Driven by significant advancements in ultrafast laser technology,such as generating isolated attosecond pulses,ATAS enables detailed investigations of ultrafast electronic processes with unprecedented time resolution.The article introduces the fundamental principles and historical development of ATAS.Applications of ATAS are discussed in three main domains:in atoms,where it has been used to study build-up dynamics of Autler–Townes splitting,Fano resonance,light-induced states,etc.;in molecules,where it has revealed coherent molecular wavepacket dynamics and non-adiabatic dynamics near conical intersections;and in solids,where it has been extended to investigate ultrafast charge carrier dynamics in metals,semiconductors,and insulators.The review highlights the potential of ATAS in developing ultrafast optical switches and petahertz electronics.The ability of ATAS to probe and manipulate electronic dynamics at the attosecond timescale provides a powerful tool for exploring the fundamental limits of electronic and optical processes in materials.
