The efficient and accurate approximate nonlinear filters have been widely used in the estimation of states and parameters of dynamical systems. In this paper, an adaptive divided difference filter is designed for prec...The efficient and accurate approximate nonlinear filters have been widely used in the estimation of states and parameters of dynamical systems. In this paper, an adaptive divided difference filter is designed for precise estimation of states and parameters of micromechanical gyro navigation system. Based on the investigation of nonlinear divided difference filter the adaptive divided difference filter(ADDF) was designed, which takes account of the incorrect time-varying noise statistics of dynamical systems and compensation of the nonlinearity effects neglected by linearization. And its performance is superior to that of DDF and extended Kalman filter(EKF). Simulation results indicate that the advantages of the proposed nonlinear filters make them attractive alternatives to the extended Kalman filter.展开更多
Unlike mammals,zebrafish possess a remarkable ability to regenerate their spinal cord after injury,making them an ideal vertebrate model for studying regeneration.While previous research has identified key cell types ...Unlike mammals,zebrafish possess a remarkable ability to regenerate their spinal cord after injury,making them an ideal vertebrate model for studying regeneration.While previous research has identified key cell types involved in this process,the underlying molecular and cellular mechanisms remain largely unexplored.In this study,we used single-cell RNA sequencing to profile distinct cell populations at different stages of spinal cord injury in zebrafish.Our analysis revealed that multiple subpopulations of neurons showed persistent activation of genes associated with axonal regeneration post injury,while molecular signals promoting growth cone collapse were inhibited.Radial glial cells exhibited significant proliferation and differentiation potential post injury,indicating their intrinsic roles in promoting neurogenesis and axonal regeneration,respectively.Additionally,we found that inflammatory factors rapidly decreased in the early stages following spinal cord injury,creating a microenvironment permissive for tissue repair and regeneration.Furthermore,oligodendrocytes lost maturity markers while exhibiting increased proliferation following injury.These findings demonstrated that the rapid and orderly regulation of inflammation,as well as the efficient proliferation and redifferentiation of new neurons and glial cells,enabled zebrafish to reconstruct the spinal cord.This research provides new insights into the cellular transitions and molecular programs that drive spinal cord regeneration,offering promising avenues for future research and therapeutic strategies.展开更多
In this study, numerical optimisation and experimental validation of a divided rail freight brake disc crown made of grey cast iron EN-GJL-250 is presented.The analysed brake disc is used in rail freight wagons and po...In this study, numerical optimisation and experimental validation of a divided rail freight brake disc crown made of grey cast iron EN-GJL-250 is presented.The analysed brake disc is used in rail freight wagons and possesses a load capacity of 22.5 tons per axle. Two of the divided rail freight brake discs are mounted on each axle.With the aid of numerical analysis, the thermal dissipation properties of the brake disc were optimised and ventilation losses were reduced, and the numerical results were compared with experimental results. A one-way fluid–structure interaction analysis was performed. A computational fluid dynamic model of a divided rail freight brake disc, used to predict air flow properties and heat convection, was incorporated into a finite element model of the disc and used to evaluate the temperature of the disc. A numerical parametrical optimisation of cooling ribs of the brake disc was also performed, and novel optimised cooling ribs were developed. A transient thermal numerical analysis of the brake disc was validated using temperature measurements obtained during a braking test on a test bench. The ventilation losses of the brake disc were measured on a test bench specifically designed for the task, and the losses were compared to the simulation results. The experimentally obtained ventilation losses and temperature measurements compared favourably with the simulation results, confirming that this type of simulation process may be confidently applied in the future. Through systematic optimisation of the divided rail freight brake disc, ventilation losses were reduced by 37% and the mass was reduced by 21%, resulting in better thermal performance that will bring with it substantial energy savings.展开更多
Through separation of the hexane-heptane–octane system in a cross-wall adiabatic dividing wall column, the effects of feed position, side-draw position, liquid split ratio, vapor split ratio and their interactions on...Through separation of the hexane-heptane–octane system in a cross-wall adiabatic dividing wall column, the effects of feed position, side-draw position, liquid split ratio, vapor split ratio and their interactions on the energy consumption were analyzed by Aspen Plus under the constant product purity, and the response surface model for the energy consumption was regressed. Based on the restriction on the optimal operating zone, the comparison of different combinations of surrogate models and optimization methods showed that, the combination of the Kriging model and multi-island genetic algorithm(Kriging-MIGA) had better prediction ability than the combination of the response surface model and partial derivative method(RSM-PD), and RSM-PD had better optimization effect than Kriging-MIGA. With a self-made cross-wall adiabatic dividing wall column, the temperature at measuring points and the energy consumption were measured during experiments, the comparison between measured values and simulated ones demonstrated that the optimized values of variables searched by RSM-PD and Kriging-MIGA could be both used as the optimum technological conditions since the experimental reliability was ensured, with the optimum technological conditions shown below: The feed position is 6, the side-draw position is 7, the combinations of liquid split ratio and vapor split ratio are [0.14, 0.5] and [0.16, 0.52], respectively. RSM-PD and Kriging-MIGA can provide the appropriate optimization methods for the dividing wall column.展开更多
New sigma point filtering algorithms, including the unscented Kalman filter （UKF） and the divided difference filter （DDF）, are designed to solve the nonlinear filtering problem under the condition of correlated no...New sigma point filtering algorithms, including the unscented Kalman filter （UKF） and the divided difference filter （DDF）, are designed to solve the nonlinear filtering problem under the condition of correlated noises. Based on the minimum mean square error estimation theory, the nonlinear optimal predictive and correction recursive formulas under the hypothesis that the input noise is correlated with the measurement noise are derived and can be described in a unified framework. Then, UKF and DDF with correlated noises are proposed on the basis of approximation of the posterior mean and covariance in the unified framework by using unscented transformation and second order Stirling＇s interpolation. The proposed UKF and DDF with correlated noises break through the limitation that input noise and measurement noise must be assumed to be uneorrelated in standard UKF and DDF. Two simulation examples show the effectiveness and feasibility of new algorithms for dealing with nonlinear filtering issue with correlated noises.展开更多
Modeling height–diameter relationships is an important component in estimating and predicting forest development under different forest management scenarios. In this paper, ten widely used candidate height–diameter ...Modeling height–diameter relationships is an important component in estimating and predicting forest development under different forest management scenarios. In this paper, ten widely used candidate height–diameter models were fitted to tree height and diameter at breast height（DBH）data for Populus euphratica Oliv. within a 100 ha permanent plots at Arghan Village in the lower reaches of the Tarim River, Xinjiang Uyghur Autonomous Region of China. Data from 4781 trees were used and split randomly into two sets：75 % of the data were used to estimate model parameters（model calibration）, and the remaining data（25 %） were reserved for model validation. All model performances were evaluated and compared by means of multiple model performance criteria such as asymptotic t-statistics of model parameters, standardized residuals against predicted height,root mean square error（RMSE）, Akaike’s informationcriterion（AIC）, mean prediction error（ME） and mean absolute error（MAE）. The estimated parameter a for model（6） was not statistically significant at a level of a = 0.05. RMSE and AIC test result for all models showed that exponential models（1）,（2）,（3） and（4） performed significantly better than others. All ten models had very small MEs and MAEs. Nearly all models underestimated tree heights except for model（6）. Comparing the MEs and MAEs of models, model（1） produced smaller MEs（0.0059） and MAEs（1.3754） than other models. To assess the predictive performance of models, we also calculated MEs by dividing the model validation data set into 10-cm DBH classes. This suggested that all models were likely to create higher mean prediction errors for tree DBH classes[20 cm. However, no clear trend was found among models.Model（6） generated significantly smaller mean prediction errors across all tree DBH classes. Considering all the aforementioned criteria, model（1）： TH ？ 1：3 t a= e1 t b？eàc？DBHT and model（6）： TH ？ 1：3 t DBH2= ea t b？DBH t c ？ DBH2T are recommended as suitable models for describing the height–diameter relationship of P. euphratica. The limitations of other models showing poor performance in predicting tree height are discussed. We provide explanations for these shortcomings.展开更多
This paper numerically simulates the stress development and generates a three-dimensional model of the medium-length hole blasting in infinite rock mass for continuous charge and divided charge in blasting by using th...This paper numerically simulates the stress development and generates a three-dimensional model of the medium-length hole blasting in infinite rock mass for continuous charge and divided charge in blasting by using the large-scale nonlinear dynamic analysis software LS-DYNA and the elastic-plastic model ~*MAT_PLASTIC_KINEMATIC and JWO-EOS.The differences of the decreasing rate in Von Mises effective stress of blasting,element effective stress peak of free surface,bore wall stress and acceleration are investigated.It is shown that divided charge could greatly improve the blasting effect by engineering blasting practice.展开更多
The paper is designed to research the translation practice of Divided We Stand from the perspective of Translator Behavior Criticism.Thus,the paper uses the tools of degree of truth-seeking,degree of utility and degre...The paper is designed to research the translation practice of Divided We Stand from the perspective of Translator Behavior Criticism.Thus,the paper uses the tools of degree of truth-seeking,degree of utility and degree of rationality under the macro-guidance of Truth-seeking-Utility-attaining evaluative model of continuum.Specifically from the perspective of intra-translation,extra-translation and non-translation,the paper research and evaluate the translation practice.展开更多
Presents the division of non developable ruled surface into divided small areas and flank milling in these divided areas to improve machining efficiency and machined surface quality by controlling the machining error ...Presents the division of non developable ruled surface into divided small areas and flank milling in these divided areas to improve machining efficiency and machined surface quality by controlling the machining error for each area, and the algorithms developed for generation of tool path and calculation of errors, and concludes from computer simulation results that the algorithms are correct.展开更多
A second-order divided difference filter (SDDF) is derived for integrating line of sight measurement from vision sensor with acceleration and angular rate measurements of the follower to estimate the precise relative ...A second-order divided difference filter (SDDF) is derived for integrating line of sight measurement from vision sensor with acceleration and angular rate measurements of the follower to estimate the precise relative position,velocity and attitude of two unmanned aerial vehicles (UAVs).The second-order divided difference filter which makes use of multidimensional interpolation formulations to approximate the nonlinear transformations could achieve more accurate estimation and faster convergence from inaccurate initial conditions than standard extended Kalman filter.The filter formulation is based on relative motion equations.The global attitude parameterization is given by quarternion,while a generalized three-dimensional attitude representation is used to define the local attitude error.Simulation results are shown to compare the performance of the second-order divided difference filter with a standard extended Kalman filter approach.展开更多
A square-root version of the divided difference Rauch-Tung-Striebel (RTS) smoother is proposed in this paper. The square-root variant essentially propagates the square roots of the covariance matrices and can consiste...A square-root version of the divided difference Rauch-Tung-Striebel (RTS) smoother is proposed in this paper. The square-root variant essentially propagates the square roots of the covariance matrices and can consistently improve the numerical stability because all the resulting covariance matrices are guaranteed to stay positive semi-definite. Furthermore, the square-root form ensures reliable implementation in an embedded system with fixed or limited precision although it is algebraically equivalent to the standard form. The new smoothing algorithm is tested in a challenging two-dimensional maneuvering target tracking problem with unknown and time-varying turn rate, and its performance is compared with that of other de-facto standard filters and smoothers. The simulation results indicate that the proposed RTS smoother markedly outperforms the associated filters and gives slightly smaller error than an unscented-based RTS smoother.展开更多
The effect of acute and chronic exposure to toxicmetals like CsCl and CoCl<sub>2</sub> on chromosomes and celldivision was studied in seeds of Trigonellafoenum graecum and root meristems of Alliumsativum.1...The effect of acute and chronic exposure to toxicmetals like CsCl and CoCl<sub>2</sub> on chromosomes and celldivision was studied in seeds of Trigonellafoenum graecum and root meristems of Alliumsativum.10,000,1000 & 100 ppm of CsCl and 1%,展开更多
Average(mean)voter is one of the commonest voting methods suitable for decision making in highly-available and long-missions applications where the availability and the speed of the system are critical.In this paper,a...Average(mean)voter is one of the commonest voting methods suitable for decision making in highly-available and long-missions applications where the availability and the speed of the system are critical.In this paper,a new generation of average voter based on parallel algorithms and parallel random access machine(PRAM)structure are proposed.The analysis shows that this algorithm is optimal due to its improved time complexity,speed-up,and efficiency and is especially appropriate for applications where the size of input space is large.展开更多
A hierarchical robot control is proposed for robot soccer system. The Newton’s divided difference is utilized in robot path planning. This paper describes the problems encoutered, software design considerations, visi...A hierarchical robot control is proposed for robot soccer system. The Newton’s divided difference is utilized in robot path planning. This paper describes the problems encoutered, software design considerations, vision algorithm and controls of individual robots. The solutions to the problems implemented are simple and direct. It is observed that many of the ideas and solutions can be evolved based on simple theories and concepts. This paper focuses on software structure of multi agent controls, vision algorithm and simple path planning method.展开更多
This paper presents a new nonstationary iterative method for solving non linear algebraic equations that does not require the use of any derivative. The study uses only the Newton’s divided differences of first and s...This paper presents a new nonstationary iterative method for solving non linear algebraic equations that does not require the use of any derivative. The study uses only the Newton’s divided differences of first and second orders instead of the derivatives of (1).展开更多
Sites with varying geometric features were analyzed to develop the 85 th percentile speed prediction models for car and sports utility vehicle(SUV) at 50 m prior to the point of curvature(PC), PC, midpoint of a curve(...Sites with varying geometric features were analyzed to develop the 85 th percentile speed prediction models for car and sports utility vehicle(SUV) at 50 m prior to the point of curvature(PC), PC, midpoint of a curve(MC), point of tangent(PT) and 50 m beyond PT on four-lane median divided rural highways. The car and SUV speed data were combined in the analysis as they were found to be normally distributed and not significantly different. Independent parameters representing geometric features and speed at the preceding section were logically selected in stepwise regression analyses to develop the models. Speeds at various locations were found to be dependent on some combinations of curve length, curvature and speed in the immediately preceding section of the highway. Curve length had a significant effect on the speed at locations 50 m prior to PC, PC and MC. The effect of curvature on speed was observed only at MC. The curve geometry did not have a significant effect on speed from PT onwards. The speed at 50 m prior to PC and curvature is the most significant parameter that affects the speed at PC and MC, respectively. Before entering a horizontal curve, drivers possibly perceive the curve based on its length. Longer curve encourages drivers to maintain higher speed in the preceding tangent section. Further, drivers start experiencing the effect of curvature only after entering the curve and adjust speed accordingly. Practitioners can use these findings in designing consistent horizontal curve for vehicle speed harmony.展开更多
A new set of steps for dividing process, the Reversed Dividing Process, is introduced, in which the position based number representation digits for the value of l/X are reversely output one by one compared with digit ...A new set of steps for dividing process, the Reversed Dividing Process, is introduced, in which the position based number representation digits for the value of l/X are reversely output one by one compared with digit output order of the normal dividing process.展开更多
Aims:Divided nevus of the eyelid is a congenital pigmented nevus that impacts eyelid function and aesthetics.While surgical excision and laser ablation are current treatment options,they have limitations when dealing ...Aims:Divided nevus of the eyelid is a congenital pigmented nevus that impacts eyelid function and aesthetics.While surgical excision and laser ablation are current treatment options,they have limitations when dealing with large lesions.This study aims to investigate the efficacy and safety of carbon dioxide(CO_(2))laser excision treatment for divided nevus of the eyelid.Methods:This retrospective study included 10 patients(5 males,5 females)with a mean age of 23.7 years(9-54 years).All underwent CO_(2)laser excision and were followed up for 12 months.Treatment outcomes were assessed through clearance and recurrence rates,evaluated using digital photography.Postoperative complications were closely monitored throughout the 12-month follow-up period.Patient satisfaction was assessed using a comprehensive questionnaire.Results:All patients presented with unilateral divided nevus of the eyelid,with lesion diameters ranging from 25 to 50 mm and heights ranging from 0.3 to 6 mm(mean:3.93 mm).Patients received between 1 and 5 laser treatment sessions.At the 12-month follow-up,a 100%clearance rate was achieved,with no recurrence observed in any patient.All patients maintained a continuous eyelid margin with acceptable irregularity.Complications were minimal,with partial eyelash loss in 8 patients,hyperpigmentation in 2 patients,and mild upper eyelid trichiasis in 1 patient.No severe complications,such as ectropion,eyelid margin notching,corneal erosion,or significant scar hypertrophy,were reported.All patients expressed being"very satisfied"with the functional and cosmetic outcomes in a questionnaire.Conclusions:CO_(2)laser excision offers a simple,precise,and effective treatment approach for divided nevus of the eyelid.This innovative technique simplifies the treatment process,achieves excellent cosmetic outcomes,and eliminates the need for skin grafting,making it a promising option for the management of large divided nevus.展开更多
A new and fundamentally different geology and glacial history paradigm (new paradigm) is used to interpret previously ignored and unexplained drainage system and erosional landform evidence shown on the 1893 United St...A new and fundamentally different geology and glacial history paradigm (new paradigm) is used to interpret previously ignored and unexplained drainage system and erosional landform evidence shown on the 1893 United States Geological Survey Cranberry, North Carolina 1:125,000 scale topographic map (which has a 100-foot or about a 30-meter contour interval). In most regions including the Cranberry map area, geomorphologists have never been able to use the accepted geology and glacial history paradigm (accepted paradigm) to explain most of the topographic map drainage system and erosional landform evidence. Probably for that reason, drainage system and erosional landform evidence shown on the 1893 Cranberry topographic map and its adjacent topographic maps has been ignored for 130 years. This study demonstrates how a new geology and glacial history paradigm (new paradigm) which was developed by using Great Plains and Rocky Mountain topographic map evidence explains the 1893 Cranberry map drainage system and erosional landform evidence (and similar evidence from a small area on the adjacent 1905 Morgantown map). The new paradigm sees the Cranberry map area as being located along the southeastern rim of a continental ice sheet created and occupied deep “hole” with regional erosion occurring and present-day drainage systems developing when the headward erosion of southeast-oriented valleys from the Atlantic Ocean and of northwest-oriented valleys from the developing deep “hole” into the gradually rising deep “hole” rim captured massive and prolonged south- and southwest-oriented meltwater floods. The new paradigm permits explanations for most drainage divides, named and unnamed gaps, barbed tributaries, through valleys extending across drainage divides, isolated erosional remnants, diverging and converging valleys, and unusual river and stream direction changes which the 1893 Cranberry topographic map shows.展开更多
文摘The efficient and accurate approximate nonlinear filters have been widely used in the estimation of states and parameters of dynamical systems. In this paper, an adaptive divided difference filter is designed for precise estimation of states and parameters of micromechanical gyro navigation system. Based on the investigation of nonlinear divided difference filter the adaptive divided difference filter(ADDF) was designed, which takes account of the incorrect time-varying noise statistics of dynamical systems and compensation of the nonlinearity effects neglected by linearization. And its performance is superior to that of DDF and extended Kalman filter(EKF). Simulation results indicate that the advantages of the proposed nonlinear filters make them attractive alternatives to the extended Kalman filter.
基金supported by the Jiangsu Province Traditional Chinese Medicine Technology Development Plan Project,Nos.MS2023113(to JC),MS2022090Young and Middle-aged Academic Leaders of Jiangsu Qing-Lan Project(to GL).
文摘Unlike mammals,zebrafish possess a remarkable ability to regenerate their spinal cord after injury,making them an ideal vertebrate model for studying regeneration.While previous research has identified key cell types involved in this process,the underlying molecular and cellular mechanisms remain largely unexplored.In this study,we used single-cell RNA sequencing to profile distinct cell populations at different stages of spinal cord injury in zebrafish.Our analysis revealed that multiple subpopulations of neurons showed persistent activation of genes associated with axonal regeneration post injury,while molecular signals promoting growth cone collapse were inhibited.Radial glial cells exhibited significant proliferation and differentiation potential post injury,indicating their intrinsic roles in promoting neurogenesis and axonal regeneration,respectively.Additionally,we found that inflammatory factors rapidly decreased in the early stages following spinal cord injury,creating a microenvironment permissive for tissue repair and regeneration.Furthermore,oligodendrocytes lost maturity markers while exhibiting increased proliferation following injury.These findings demonstrated that the rapid and orderly regulation of inflammation,as well as the efficient proliferation and redifferentiation of new neurons and glial cells,enabled zebrafish to reconstruct the spinal cord.This research provides new insights into the cellular transitions and molecular programs that drive spinal cord regeneration,offering promising avenues for future research and therapeutic strategies.
基金supported by the European Union’s Horizon 2020 researchinnovation programme FUTURA under Grant Agreement No. 700985
文摘In this study, numerical optimisation and experimental validation of a divided rail freight brake disc crown made of grey cast iron EN-GJL-250 is presented.The analysed brake disc is used in rail freight wagons and possesses a load capacity of 22.5 tons per axle. Two of the divided rail freight brake discs are mounted on each axle.With the aid of numerical analysis, the thermal dissipation properties of the brake disc were optimised and ventilation losses were reduced, and the numerical results were compared with experimental results. A one-way fluid–structure interaction analysis was performed. A computational fluid dynamic model of a divided rail freight brake disc, used to predict air flow properties and heat convection, was incorporated into a finite element model of the disc and used to evaluate the temperature of the disc. A numerical parametrical optimisation of cooling ribs of the brake disc was also performed, and novel optimised cooling ribs were developed. A transient thermal numerical analysis of the brake disc was validated using temperature measurements obtained during a braking test on a test bench. The ventilation losses of the brake disc were measured on a test bench specifically designed for the task, and the losses were compared to the simulation results. The experimentally obtained ventilation losses and temperature measurements compared favourably with the simulation results, confirming that this type of simulation process may be confidently applied in the future. Through systematic optimisation of the divided rail freight brake disc, ventilation losses were reduced by 37% and the mass was reduced by 21%, resulting in better thermal performance that will bring with it substantial energy savings.
基金the financial support by the National Natural Science Foundation of China (21306036)
文摘Through separation of the hexane-heptane–octane system in a cross-wall adiabatic dividing wall column, the effects of feed position, side-draw position, liquid split ratio, vapor split ratio and their interactions on the energy consumption were analyzed by Aspen Plus under the constant product purity, and the response surface model for the energy consumption was regressed. Based on the restriction on the optimal operating zone, the comparison of different combinations of surrogate models and optimization methods showed that, the combination of the Kriging model and multi-island genetic algorithm(Kriging-MIGA) had better prediction ability than the combination of the response surface model and partial derivative method(RSM-PD), and RSM-PD had better optimization effect than Kriging-MIGA. With a self-made cross-wall adiabatic dividing wall column, the temperature at measuring points and the energy consumption were measured during experiments, the comparison between measured values and simulated ones demonstrated that the optimized values of variables searched by RSM-PD and Kriging-MIGA could be both used as the optimum technological conditions since the experimental reliability was ensured, with the optimum technological conditions shown below: The feed position is 6, the side-draw position is 7, the combinations of liquid split ratio and vapor split ratio are [0.14, 0.5] and [0.16, 0.52], respectively. RSM-PD and Kriging-MIGA can provide the appropriate optimization methods for the dividing wall column.
基金Projects(61135001, 61075029, 61074155) supported by the National Natural Science Foundation of ChinaProject(20110491690) supported by the Postdocteral Science Foundation of China
文摘New sigma point filtering algorithms, including the unscented Kalman filter （UKF） and the divided difference filter （DDF）, are designed to solve the nonlinear filtering problem under the condition of correlated noises. Based on the minimum mean square error estimation theory, the nonlinear optimal predictive and correction recursive formulas under the hypothesis that the input noise is correlated with the measurement noise are derived and can be described in a unified framework. Then, UKF and DDF with correlated noises are proposed on the basis of approximation of the posterior mean and covariance in the unified framework by using unscented transformation and second order Stirling＇s interpolation. The proposed UKF and DDF with correlated noises break through the limitation that input noise and measurement noise must be assumed to be uneorrelated in standard UKF and DDF. Two simulation examples show the effectiveness and feasibility of new algorithms for dealing with nonlinear filtering issue with correlated noises.
基金supported by the National Natural Science Foundation of China(Grant No:31360200,31270742)German Federal Ministry of Education and Research(BMBF)within the framework of the SuMaRiO project(01LL0918D)the Volkswagen Stiftung(Eco CAR project,Az.88497)
文摘Modeling height–diameter relationships is an important component in estimating and predicting forest development under different forest management scenarios. In this paper, ten widely used candidate height–diameter models were fitted to tree height and diameter at breast height（DBH）data for Populus euphratica Oliv. within a 100 ha permanent plots at Arghan Village in the lower reaches of the Tarim River, Xinjiang Uyghur Autonomous Region of China. Data from 4781 trees were used and split randomly into two sets：75 % of the data were used to estimate model parameters（model calibration）, and the remaining data（25 %） were reserved for model validation. All model performances were evaluated and compared by means of multiple model performance criteria such as asymptotic t-statistics of model parameters, standardized residuals against predicted height,root mean square error（RMSE）, Akaike’s informationcriterion（AIC）, mean prediction error（ME） and mean absolute error（MAE）. The estimated parameter a for model（6） was not statistically significant at a level of a = 0.05. RMSE and AIC test result for all models showed that exponential models（1）,（2）,（3） and（4） performed significantly better than others. All ten models had very small MEs and MAEs. Nearly all models underestimated tree heights except for model（6）. Comparing the MEs and MAEs of models, model（1） produced smaller MEs（0.0059） and MAEs（1.3754） than other models. To assess the predictive performance of models, we also calculated MEs by dividing the model validation data set into 10-cm DBH classes. This suggested that all models were likely to create higher mean prediction errors for tree DBH classes[20 cm. However, no clear trend was found among models.Model（6） generated significantly smaller mean prediction errors across all tree DBH classes. Considering all the aforementioned criteria, model（1）： TH ？ 1：3 t a= e1 t b？eàc？DBHT and model（6）： TH ？ 1：3 t DBH2= ea t b？DBH t c ？ DBH2T are recommended as suitable models for describing the height–diameter relationship of P. euphratica. The limitations of other models showing poor performance in predicting tree height are discussed. We provide explanations for these shortcomings.
基金National Natural Science Foundation of China （No. 51304087） Foundation Projects of Yun- nan Province （No. KKSY201404056, No. KKSA201121083）
文摘This paper numerically simulates the stress development and generates a three-dimensional model of the medium-length hole blasting in infinite rock mass for continuous charge and divided charge in blasting by using the large-scale nonlinear dynamic analysis software LS-DYNA and the elastic-plastic model ~*MAT_PLASTIC_KINEMATIC and JWO-EOS.The differences of the decreasing rate in Von Mises effective stress of blasting,element effective stress peak of free surface,bore wall stress and acceleration are investigated.It is shown that divided charge could greatly improve the blasting effect by engineering blasting practice.
文摘The paper is designed to research the translation practice of Divided We Stand from the perspective of Translator Behavior Criticism.Thus,the paper uses the tools of degree of truth-seeking,degree of utility and degree of rationality under the macro-guidance of Truth-seeking-Utility-attaining evaluative model of continuum.Specifically from the perspective of intra-translation,extra-translation and non-translation,the paper research and evaluate the translation practice.
文摘Presents the division of non developable ruled surface into divided small areas and flank milling in these divided areas to improve machining efficiency and machined surface quality by controlling the machining error for each area, and the algorithms developed for generation of tool path and calculation of errors, and concludes from computer simulation results that the algorithms are correct.
基金Sponsored by the Aerospace Technology Innovation Funding(Grant No. CASC0209)
文摘A second-order divided difference filter (SDDF) is derived for integrating line of sight measurement from vision sensor with acceleration and angular rate measurements of the follower to estimate the precise relative position,velocity and attitude of two unmanned aerial vehicles (UAVs).The second-order divided difference filter which makes use of multidimensional interpolation formulations to approximate the nonlinear transformations could achieve more accurate estimation and faster convergence from inaccurate initial conditions than standard extended Kalman filter.The filter formulation is based on relative motion equations.The global attitude parameterization is given by quarternion,while a generalized three-dimensional attitude representation is used to define the local attitude error.Simulation results are shown to compare the performance of the second-order divided difference filter with a standard extended Kalman filter approach.
基金the Fundamental Research Fund of Northwestern Polytechnical University( Grant No. JC20120210,JC20110238)
文摘A square-root version of the divided difference Rauch-Tung-Striebel (RTS) smoother is proposed in this paper. The square-root variant essentially propagates the square roots of the covariance matrices and can consistently improve the numerical stability because all the resulting covariance matrices are guaranteed to stay positive semi-definite. Furthermore, the square-root form ensures reliable implementation in an embedded system with fixed or limited precision although it is algebraically equivalent to the standard form. The new smoothing algorithm is tested in a challenging two-dimensional maneuvering target tracking problem with unknown and time-varying turn rate, and its performance is compared with that of other de-facto standard filters and smoothers. The simulation results indicate that the proposed RTS smoother markedly outperforms the associated filters and gives slightly smaller error than an unscented-based RTS smoother.
文摘The effect of acute and chronic exposure to toxicmetals like CsCl and CoCl<sub>2</sub> on chromosomes and celldivision was studied in seeds of Trigonellafoenum graecum and root meristems of Alliumsativum.10,000,1000 & 100 ppm of CsCl and 1%,
文摘Average(mean)voter is one of the commonest voting methods suitable for decision making in highly-available and long-missions applications where the availability and the speed of the system are critical.In this paper,a new generation of average voter based on parallel algorithms and parallel random access machine(PRAM)structure are proposed.The analysis shows that this algorithm is optimal due to its improved time complexity,speed-up,and efficiency and is especially appropriate for applications where the size of input space is large.
文摘A hierarchical robot control is proposed for robot soccer system. The Newton’s divided difference is utilized in robot path planning. This paper describes the problems encoutered, software design considerations, vision algorithm and controls of individual robots. The solutions to the problems implemented are simple and direct. It is observed that many of the ideas and solutions can be evolved based on simple theories and concepts. This paper focuses on software structure of multi agent controls, vision algorithm and simple path planning method.
文摘This paper presents a new nonstationary iterative method for solving non linear algebraic equations that does not require the use of any derivative. The study uses only the Newton’s divided differences of first and second orders instead of the derivatives of (1).
基金Indian Institute of Technology Bombay for providing funding (Project code:13IRCCSG001)
文摘Sites with varying geometric features were analyzed to develop the 85 th percentile speed prediction models for car and sports utility vehicle(SUV) at 50 m prior to the point of curvature(PC), PC, midpoint of a curve(MC), point of tangent(PT) and 50 m beyond PT on four-lane median divided rural highways. The car and SUV speed data were combined in the analysis as they were found to be normally distributed and not significantly different. Independent parameters representing geometric features and speed at the preceding section were logically selected in stepwise regression analyses to develop the models. Speeds at various locations were found to be dependent on some combinations of curve length, curvature and speed in the immediately preceding section of the highway. Curve length had a significant effect on the speed at locations 50 m prior to PC, PC and MC. The effect of curvature on speed was observed only at MC. The curve geometry did not have a significant effect on speed from PT onwards. The speed at 50 m prior to PC and curvature is the most significant parameter that affects the speed at PC and MC, respectively. Before entering a horizontal curve, drivers possibly perceive the curve based on its length. Longer curve encourages drivers to maintain higher speed in the preceding tangent section. Further, drivers start experiencing the effect of curvature only after entering the curve and adjust speed accordingly. Practitioners can use these findings in designing consistent horizontal curve for vehicle speed harmony.
文摘A new set of steps for dividing process, the Reversed Dividing Process, is introduced, in which the position based number representation digits for the value of l/X are reversely output one by one compared with digit output order of the normal dividing process.
文摘Aims:Divided nevus of the eyelid is a congenital pigmented nevus that impacts eyelid function and aesthetics.While surgical excision and laser ablation are current treatment options,they have limitations when dealing with large lesions.This study aims to investigate the efficacy and safety of carbon dioxide(CO_(2))laser excision treatment for divided nevus of the eyelid.Methods:This retrospective study included 10 patients(5 males,5 females)with a mean age of 23.7 years(9-54 years).All underwent CO_(2)laser excision and were followed up for 12 months.Treatment outcomes were assessed through clearance and recurrence rates,evaluated using digital photography.Postoperative complications were closely monitored throughout the 12-month follow-up period.Patient satisfaction was assessed using a comprehensive questionnaire.Results:All patients presented with unilateral divided nevus of the eyelid,with lesion diameters ranging from 25 to 50 mm and heights ranging from 0.3 to 6 mm(mean:3.93 mm).Patients received between 1 and 5 laser treatment sessions.At the 12-month follow-up,a 100%clearance rate was achieved,with no recurrence observed in any patient.All patients maintained a continuous eyelid margin with acceptable irregularity.Complications were minimal,with partial eyelash loss in 8 patients,hyperpigmentation in 2 patients,and mild upper eyelid trichiasis in 1 patient.No severe complications,such as ectropion,eyelid margin notching,corneal erosion,or significant scar hypertrophy,were reported.All patients expressed being"very satisfied"with the functional and cosmetic outcomes in a questionnaire.Conclusions:CO_(2)laser excision offers a simple,precise,and effective treatment approach for divided nevus of the eyelid.This innovative technique simplifies the treatment process,achieves excellent cosmetic outcomes,and eliminates the need for skin grafting,making it a promising option for the management of large divided nevus.
文摘A new and fundamentally different geology and glacial history paradigm (new paradigm) is used to interpret previously ignored and unexplained drainage system and erosional landform evidence shown on the 1893 United States Geological Survey Cranberry, North Carolina 1:125,000 scale topographic map (which has a 100-foot or about a 30-meter contour interval). In most regions including the Cranberry map area, geomorphologists have never been able to use the accepted geology and glacial history paradigm (accepted paradigm) to explain most of the topographic map drainage system and erosional landform evidence. Probably for that reason, drainage system and erosional landform evidence shown on the 1893 Cranberry topographic map and its adjacent topographic maps has been ignored for 130 years. This study demonstrates how a new geology and glacial history paradigm (new paradigm) which was developed by using Great Plains and Rocky Mountain topographic map evidence explains the 1893 Cranberry map drainage system and erosional landform evidence (and similar evidence from a small area on the adjacent 1905 Morgantown map). The new paradigm sees the Cranberry map area as being located along the southeastern rim of a continental ice sheet created and occupied deep “hole” with regional erosion occurring and present-day drainage systems developing when the headward erosion of southeast-oriented valleys from the Atlantic Ocean and of northwest-oriented valleys from the developing deep “hole” into the gradually rising deep “hole” rim captured massive and prolonged south- and southwest-oriented meltwater floods. The new paradigm permits explanations for most drainage divides, named and unnamed gaps, barbed tributaries, through valleys extending across drainage divides, isolated erosional remnants, diverging and converging valleys, and unusual river and stream direction changes which the 1893 Cranberry topographic map shows.
