In this paper,we introduce the real pairwise completely positive(RPCP)matrices with one of them is necessarily positive semidefinite while the other one is necessarily entrywise nonnegative,which has a real pairwise c...In this paper,we introduce the real pairwise completely positive(RPCP)matrices with one of them is necessarily positive semidefinite while the other one is necessarily entrywise nonnegative,which has a real pairwise completely positive(RPCP)decomposition.We study the properties of RPCP matrices and give some necessary and sufficient conditions for a matrix pair to be RPCP.First,we give an equivalent decomposition for the RPCP matrices,which is different from the RPCP-decomposition and show that the matrix pair(X,X)is RPCP if and only if X is completely positive.Besides,we also prove that the RPCP matrices checking problem is equivalent to the separable completion problem.A semidefinite algorithm is also proposed for detecting whether or not a matrix pair is RPCP.The asymptotic and finite convergence of the algorithm are also discussed.If it is RPCP,we can further give a RPCP-decomposition for it;if it is not,we can obtain a certificate for this.展开更多
This article studies a class of nonlinear Kirchhoff equations with exponential critical growth,trapping potential,and perturbation.Under appropriate assumptions about f and h,the article obtained the existence of norm...This article studies a class of nonlinear Kirchhoff equations with exponential critical growth,trapping potential,and perturbation.Under appropriate assumptions about f and h,the article obtained the existence of normalized positive solutions for this equation via the Trudinger-Moser inequality and variational methods.Moreover,these solutions are also ground state solutions.Additionally,the article also characterized the asymptotic behavior of solutions.The results of this article expand the research of relevant literature.展开更多
Objective:To evaluate the predictive value of the neutrophil⁃to⁃lymphocyte ratio(NLR)and the systemic immune⁃inflammation index(SII)in predicting patients with anti⁃melanoma differentiation⁃associated gene 5⁃positive(...Objective:To evaluate the predictive value of the neutrophil⁃to⁃lymphocyte ratio(NLR)and the systemic immune⁃inflammation index(SII)in predicting patients with anti⁃melanoma differentiation⁃associated gene 5⁃positive(anti⁃MDA5+)dermatomyositis(DM)develop into the rapidly progressive interstitial lung disease(RPILD).Methods:We retrospectively analyzed the clinical and laboratory data of 124 anti⁃MDA5+DM patients from the First Affiliated Hospital of Nanjing Medical University between March 2019 and September 2023.We identified independent risk factors associated with the development and mortality of RPILD with the Cox regression analysis,and determined the optimal cut⁃off values for predicting adverse outcomes with the receiver operating characteristic(ROC)curve analysis.Results:Among the 124 patients,36 patients(29.03%)developed RPILD,and 39 patients(31.45%)died during the follow⁃up period.The results of multivariate Cox regression analysis showed that the elevated NLR was an independent risk factor for RPILD development,while the elevated SII expression was independently associated with the increased mortality of RPILD.Based on the ROC curve analysis,NLR>6.12 was a predictor for RPILD,and SII>875.79 was associated with increased mortality risk of RPILD.Conclusion:Both NLR and SII are accessible,cost⁃effective,and reliable prognostic indicators for the prognosis of patients with anti⁃MDA5^(+)DM,providing a valuable guidance for clinical management and risk stratification of the disease.展开更多
The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave...The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave infrared wavelengths as beacon light can reduce atmospheric absorption and signal attenuation.However,there are strong non-uniformity and blind pixels in the short-wave infrared image,which makes the image distorted and leads to the decrease of spot centroid positioning accuracy.Therefore,the high-precision localization of the spot centroid of the short-wave infrared images is of great research significance.A high-precision spot centroid positioning model for short-wave infrared is proposed to correct for non-uniformity and blind pixels in short-wave infrared images and quantify the localization errors caused by the two,further model-based localization error simulations are performed,and a novel spot centroid positioning payload for satellite laser communications has been designed using the latest 640×512 planar array InGaAs shortwave infrared detector.The experimental results show that the non-uniformity of the corrected image is reduced from 7%to 0.6%,the blind pixels rejection rate reaches 100%,the frame rate can be up to 2000 Hz,and the spot centroid localization accuracy is as high as 0.1 pixel point,which realizes high-precision spot centroid localization of high-frame-frequency short-wave infrared images.展开更多
In this paper,a novel train positioning method considering satellite raw observation data was proposed,which aims to promote train positioning performance from an innovative perspective of the train satellite-based po...In this paper,a novel train positioning method considering satellite raw observation data was proposed,which aims to promote train positioning performance from an innovative perspective of the train satellite-based positioning error sources.The method focused on overcoming the abnormal observations in satellite observation data caused by railway environment rather than the positioning results.Specifically,the relative positioning experimental platform was built and the zero-baseline method was firstly employed to evaluate the carrier phase data quality,and then,GNSS combined observation models were adopted to construct the detection values,which were applied to judge abnormal-data through the dual-frequency observations.Further,ambiguity fixing optimization was investigated based on observation data selection in partly-blocked environments.The results show that the proposed method can effectively detect and address abnormal observations and improve positioning stability.Cycle slips and gross errors can be detected and identified based on dual-frequency global navigation satellite system data.After adopting the data selection strategy,the ambiguity fixing percentage was improved by 29.2%,and the standard deviation in the East,North,and Up components was enhanced by 12.7%,7.4%,and 12.5%,respectively.The proposed method can provide references for train positioning performance optimization in railway environments from the perspective of positioning error sources.展开更多
Background and objective EGFR-tyrosine kinase inhibitors(EGFR-TKIs) were used to treat non-small cell lung cancer(NSCLC) patients with EGFR mutation positive. This study aims to compare the effectiveness of first line...Background and objective EGFR-tyrosine kinase inhibitors(EGFR-TKIs) were used to treat non-small cell lung cancer(NSCLC) patients with EGFR mutation positive. This study aims to compare the effectiveness of first line TKIs;gefitinib, erlotinib, and afatinib in the treatment of advanced stage NSCLC patients with EGFR mutation positive in the Indonesian population.Methods A retrospective cohort study of 88 NSCLC patients with EGFR mutation positive treated with gefitinib(n=59), erlotinib(n=22), and afatinib(n=7) was performed in national cancer hospital in Indonesia.Inclusion criteria were stage IIIb or IV NSCLC with adenocarcinoma subtype. Subjects less than 18 years or with a history of other malignancy were excluded. Outcomes were treatment response, progression-free survival(PFS), and mortality rate. Results Complete response, partial response, and stable disease were shown in 1.1%, 35.2%, and 31.8% of subjects, respectively. There were 31.8% of subjects developed progressive disease during treatment. Regarding EGFR mutation positive profile, a total of 56.8% subjects had deletion in exon 19, 42% subjects had mutation in exon 21, and rare mutation in exon 18 was found in 3.4% of total subjects. Demography and clinical characteristics had no significant association with the risk of progressive disease. The median PFS of subjects was 11 months(95%CI: 6.8-15.2 months). There was no statistical difference of PFS between treatment groups.Conclusion Gefitinib, erlotinib, and afatinib have similar effectiveness in advanced stage NSCLC with EGFR mutation positive. Afatinib tends to be associated with longer PFS but further investigation is required.展开更多
Based on Fermat’s principle, two-point ray tracing method was studied in three-dimensional structure. By means of first order Taylor’s incomplete series expansion (i.e. no expansion to the length of the ray), a symm...Based on Fermat’s principle, two-point ray tracing method was studied in three-dimensional structure. By means of first order Taylor’s incomplete series expansion (i.e. no expansion to the length of the ray), a symmetry block tridiagonal matrix equation set was deduced. Further, the positive definiteness of coefficient matrix was discussed, and the positive definiteness was accurately proved in a mathematical way. It assured that the algorithm was well-posed. Associated with iterative method, the solution to ray tracing can be got through step-by-step linearized iteration of the nonlinear problem. An algorithm of the whole path iterative ray tracing method in three-dimensional velocity structure was obtained. This method shows a clear and simple as well as explicit computation formula, which makes ray tracing computation easily applicable in practice. The correction vector is obtained through finding the solution to the positive definite block tridiagonal equation set, which ensures the method is robust convergence. This study offers a new kind of feasible and efficient ray tracing method for three dimensional seismic migration and tomography. Meanwhile, it also provides the prerequisite guarantee to design a fast algorithm.展开更多
A series of positive electrodes for Ni/MH battery were fabricated by addition of CoO.The morphology and microstructure of the electrodes were examined by SEM and EDS, and electrochemical behavior was investigated in t...A series of positive electrodes for Ni/MH battery were fabricated by addition of CoO.The morphology and microstructure of the electrodes were examined by SEM and EDS, and electrochemical behavior was investigated in three-compartment appliances at room temperature.The electrochemical performance of the positive electrodes with CoO was improved. Under the same charge-discharge cycle, the electrodes with CoO showed higher specific capacity, lower charge mean voltage and higher discharge mean voltage. But ...展开更多
In this paper, author abtains a group of characteristic conditions for the infinitesimal generators of positive contraction semigroups and stochastic semigroups.Furthermore, Applications of them to linear transport th...In this paper, author abtains a group of characteristic conditions for the infinitesimal generators of positive contraction semigroups and stochastic semigroups.Furthermore, Applications of them to linear transport theory are discussed.展开更多
An overview of some popular rotary and reciprocating positive displacement( PD) pump types is given with the objective of presenting and comparing the respective sizing relationships and performance features. Reciproc...An overview of some popular rotary and reciprocating positive displacement( PD) pump types is given with the objective of presenting and comparing the respective sizing relationships and performance features. Reciprocating pumps discussed are the piston and plunger types. Rotary pumps addressed are gear( external and internal),vane,lobe,screw,and liquid ring pumps. To put the relative pump sizes in perspective,attention is fixed on the rotors or reciprocating elements of PD pumps,just as impellers indicate the sizes of rotodynamic pumps. The size of a PD pump is found from a dimensionless combination of displacement flow rate,rotative speed and diameter. The flow rate,head( or pressure rise) and power are related through the component efficiencies. The cavitation coefficient,often close to unity,connects the rotor tip speed or piston speed with the required NPSH,which can also be affected by the pressure rise of the pump due to leakage across the internal clearances. Operational effects due to cavitation,ingestion of gas or abrasives,and viscous and non-Newtonian fluids are discussed.展开更多
The academic world has at least nine viewpoints on the Marx's thought in the high school period: devout religious theology,moral theology,liberalism,democracy,utopian socialism,populism,ethical communism,French ma...The academic world has at least nine viewpoints on the Marx's thought in the high school period: devout religious theology,moral theology,liberalism,democracy,utopian socialism,populism,ethical communism,French materialism,the flash of historical materialism,etc. We believe that these views cannot reflect the background of Marx's thoughts in high school. Marx's three high school papers in 1835 reflected the germination of Marx's positive free thoughts in his high school. Marx's positive free thoughts contain a the relatively complete structure of three aspects of the general reason ability of freedom,the special conditions for freedom,and the specific historical form of freedom. The positive free thought in Marx's high school period is finally realized in his communist theory through the his revolution of dialectical materialism and historical materialism.展开更多
As positioning sensors,edge computation power,and communication technologies continue to develop,a moving agent can now sense its surroundings and communicate with other agents.By receiving spatial information from bo...As positioning sensors,edge computation power,and communication technologies continue to develop,a moving agent can now sense its surroundings and communicate with other agents.By receiving spatial information from both its environment and other agents,an agent can use various methods and sensor types to localize itself.With its high flexibility and robustness,collaborative positioning has become a widely used method in both military and civilian applications.This paper introduces the basic fundamental concepts and applications of collaborative positioning,and reviews recent progress in the field based on camera,LiDAR(Light Detection and Ranging),wireless sensor,and their integration.The paper compares the current methods with respect to their sensor type,summarizes their main paradigms,and analyzes their evaluation experiments.Finally,the paper discusses the main challenges and open issues that require further research.展开更多
The existing indoor fusion positioning methods based on Pedestrian Dead Reckoning(PDR)and geomagnetic technology have the problems of large initial position error,low sensor accuracy,and geomagnetic mismatch.In this s...The existing indoor fusion positioning methods based on Pedestrian Dead Reckoning(PDR)and geomagnetic technology have the problems of large initial position error,low sensor accuracy,and geomagnetic mismatch.In this study,a novel indoor fusion positioning approach based on the improved particle filter algorithm by geomagnetic iterative matching is proposed,where Wi-Fi,PDR,and geomagnetic signals are integrated to improve indoor positioning performances.One important contribution is that geomagnetic iterative matching is firstly proposed based on the particle filter algorithm.During the positioning process,an iterative window and a constraint window are introduced to limit the particle generation range and the geomagnetic matching range respectively.The position is corrected several times based on geomagnetic iterative matching in the location correction stage when the pedestrian movement is detected,which made up for the shortage of only one time of geomagnetic correction in the existing particle filter algorithm.In addition,this study also proposes a real-time step detection algorithm based on multi-threshold constraints to judge whether pedestrians are moving,which satisfies the real-time requirement of our fusion positioning approach.Through experimental verification,the average positioning accuracy of the proposed approach reaches 1.59 m,which improves 33.2%compared with the existing particle filter fusion positioning algorithms.展开更多
An efficient algorithm is proposed for computing the solution to the constrained finite time optimal control （CFTOC） problem for discrete-time piecewise affine （PWA） systems with a quadratic performance index. The...An efficient algorithm is proposed for computing the solution to the constrained finite time optimal control （CFTOC） problem for discrete-time piecewise affine （PWA） systems with a quadratic performance index. The maximal positively invariant terminal set, which is feasible and invariant with respect to a feedback control law, is computed as terminal target set and an associated Lyapunov function is chosen as terminal cost. The combination of these two components guarantees constraint satisfaction and closed-loop stability for all time. The proposed algorithm combines a dynamic programming strategy with a multi-parametric quadratic programming solver and basic polyhedral manipulation. A numerical example shows that a larger stabilizable set of states can be obtained by the proposed algorithm than precious work.展开更多
Pedestrian positioning system(PPS)using wearable inertial sensors has wide applications towards various emerging fields such as smart healthcare,emergency rescue,soldier positioning,etc.The performance of traditional ...Pedestrian positioning system(PPS)using wearable inertial sensors has wide applications towards various emerging fields such as smart healthcare,emergency rescue,soldier positioning,etc.The performance of traditional PPS is limited by the cumulative error of inertial sensors,complex motion modes of pedestrians,and the low robustness of the multi-sensor collaboration structure.This paper presents a hybrid pedestrian positioning system using the combination of wearable inertial sensors and ultrasonic ranging(H-PPS).A robust two nodes integration structure is developed to adaptively combine the motion data acquired from the single waist-mounted and foot-mounted node,and enhanced by a novel ellipsoid constraint model.In addition,a deep-learning-based walking speed estimator is proposed by considering all the motion features provided by different nodes,which effectively reduces the cumulative error originating from inertial sensors.Finally,a comprehensive data and model dual-driven model is presented to effectively combine the motion data provided by different sensor nodes and walking speed estimator,and multi-level constraints are extracted to further improve the performance of the overall system.Experimental results indicate that the proposed H-PPS significantly improves the performance of the single PPS and outperforms existing algorithms in accuracy index under complex indoor scenarios.展开更多
The author studied the existence of positive solutions of the delay logistic difference equation Δ y n=p ny n(1-y τ(n) ), n =0,1,2,.... where { p n } is a sequence of positive real numbers, { τ(n) } is a nondecreas...The author studied the existence of positive solutions of the delay logistic difference equation Δ y n=p ny n(1-y τ(n) ), n =0,1,2,.... where { p n } is a sequence of positive real numbers, { τ(n) } is a nondecreasing sequence of integers, τ(n)<n and lim n →∞ τ(n) =∞. A sufficient condition for the existence of positive solutions of the equation was given.展开更多
In this paper, we apply a cone theoretic fixed point theorem to obtain sufficient conditions for the existence of multiple positive periodic solutions to the higher-dimensional functional difference equations of the f...In this paper, we apply a cone theoretic fixed point theorem to obtain sufficient conditions for the existence of multiple positive periodic solutions to the higher-dimensional functional difference equations of the form:x(n+ 1) =A(n)x(n) +λh(n)f(x(n- τ(n))), n∈ Z.展开更多
文摘In this paper,we introduce the real pairwise completely positive(RPCP)matrices with one of them is necessarily positive semidefinite while the other one is necessarily entrywise nonnegative,which has a real pairwise completely positive(RPCP)decomposition.We study the properties of RPCP matrices and give some necessary and sufficient conditions for a matrix pair to be RPCP.First,we give an equivalent decomposition for the RPCP matrices,which is different from the RPCP-decomposition and show that the matrix pair(X,X)is RPCP if and only if X is completely positive.Besides,we also prove that the RPCP matrices checking problem is equivalent to the separable completion problem.A semidefinite algorithm is also proposed for detecting whether or not a matrix pair is RPCP.The asymptotic and finite convergence of the algorithm are also discussed.If it is RPCP,we can further give a RPCP-decomposition for it;if it is not,we can obtain a certificate for this.
基金Supported by National Natural Science Foundation of China(11671403,11671236)Henan Provincial General Natural Science Foundation Project(232300420113)。
文摘This article studies a class of nonlinear Kirchhoff equations with exponential critical growth,trapping potential,and perturbation.Under appropriate assumptions about f and h,the article obtained the existence of normalized positive solutions for this equation via the Trudinger-Moser inequality and variational methods.Moreover,these solutions are also ground state solutions.Additionally,the article also characterized the asymptotic behavior of solutions.The results of this article expand the research of relevant literature.
文摘Objective:To evaluate the predictive value of the neutrophil⁃to⁃lymphocyte ratio(NLR)and the systemic immune⁃inflammation index(SII)in predicting patients with anti⁃melanoma differentiation⁃associated gene 5⁃positive(anti⁃MDA5+)dermatomyositis(DM)develop into the rapidly progressive interstitial lung disease(RPILD).Methods:We retrospectively analyzed the clinical and laboratory data of 124 anti⁃MDA5+DM patients from the First Affiliated Hospital of Nanjing Medical University between March 2019 and September 2023.We identified independent risk factors associated with the development and mortality of RPILD with the Cox regression analysis,and determined the optimal cut⁃off values for predicting adverse outcomes with the receiver operating characteristic(ROC)curve analysis.Results:Among the 124 patients,36 patients(29.03%)developed RPILD,and 39 patients(31.45%)died during the follow⁃up period.The results of multivariate Cox regression analysis showed that the elevated NLR was an independent risk factor for RPILD development,while the elevated SII expression was independently associated with the increased mortality of RPILD.Based on the ROC curve analysis,NLR>6.12 was a predictor for RPILD,and SII>875.79 was associated with increased mortality risk of RPILD.Conclusion:Both NLR and SII are accessible,cost⁃effective,and reliable prognostic indicators for the prognosis of patients with anti⁃MDA5^(+)DM,providing a valuable guidance for clinical management and risk stratification of the disease.
基金Supported by the Short-wave Infrared Camera Systems(B025F40622024)。
文摘The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave infrared wavelengths as beacon light can reduce atmospheric absorption and signal attenuation.However,there are strong non-uniformity and blind pixels in the short-wave infrared image,which makes the image distorted and leads to the decrease of spot centroid positioning accuracy.Therefore,the high-precision localization of the spot centroid of the short-wave infrared images is of great research significance.A high-precision spot centroid positioning model for short-wave infrared is proposed to correct for non-uniformity and blind pixels in short-wave infrared images and quantify the localization errors caused by the two,further model-based localization error simulations are performed,and a novel spot centroid positioning payload for satellite laser communications has been designed using the latest 640×512 planar array InGaAs shortwave infrared detector.The experimental results show that the non-uniformity of the corrected image is reduced from 7%to 0.6%,the blind pixels rejection rate reaches 100%,the frame rate can be up to 2000 Hz,and the spot centroid localization accuracy is as high as 0.1 pixel point,which realizes high-precision spot centroid localization of high-frame-frequency short-wave infrared images.
基金Project(52272339)supported by the National Natural Science Foundation of ChinaProject(2023YFB390730303)supported by the National Key Research and Development Program of China+2 种基金Project(L2023G004)supported by the Science and Technology Research and Development Program of China State Railway Group Co.,Ltd.Project(QZKFKT2023-005)supported by the State Key Laboratory of Heavy-duty and Express High-power Electric Locomotive,ChinaProject(2022JZZ05)supported by the Open Foundation of MOE Key Laboratory of Engineering Structures of Heavy Haul Railway(Central South University),China。
文摘In this paper,a novel train positioning method considering satellite raw observation data was proposed,which aims to promote train positioning performance from an innovative perspective of the train satellite-based positioning error sources.The method focused on overcoming the abnormal observations in satellite observation data caused by railway environment rather than the positioning results.Specifically,the relative positioning experimental platform was built and the zero-baseline method was firstly employed to evaluate the carrier phase data quality,and then,GNSS combined observation models were adopted to construct the detection values,which were applied to judge abnormal-data through the dual-frequency observations.Further,ambiguity fixing optimization was investigated based on observation data selection in partly-blocked environments.The results show that the proposed method can effectively detect and address abnormal observations and improve positioning stability.Cycle slips and gross errors can be detected and identified based on dual-frequency global navigation satellite system data.After adopting the data selection strategy,the ambiguity fixing percentage was improved by 29.2%,and the standard deviation in the East,North,and Up components was enhanced by 12.7%,7.4%,and 12.5%,respectively.The proposed method can provide references for train positioning performance optimization in railway environments from the perspective of positioning error sources.
文摘Background and objective EGFR-tyrosine kinase inhibitors(EGFR-TKIs) were used to treat non-small cell lung cancer(NSCLC) patients with EGFR mutation positive. This study aims to compare the effectiveness of first line TKIs;gefitinib, erlotinib, and afatinib in the treatment of advanced stage NSCLC patients with EGFR mutation positive in the Indonesian population.Methods A retrospective cohort study of 88 NSCLC patients with EGFR mutation positive treated with gefitinib(n=59), erlotinib(n=22), and afatinib(n=7) was performed in national cancer hospital in Indonesia.Inclusion criteria were stage IIIb or IV NSCLC with adenocarcinoma subtype. Subjects less than 18 years or with a history of other malignancy were excluded. Outcomes were treatment response, progression-free survival(PFS), and mortality rate. Results Complete response, partial response, and stable disease were shown in 1.1%, 35.2%, and 31.8% of subjects, respectively. There were 31.8% of subjects developed progressive disease during treatment. Regarding EGFR mutation positive profile, a total of 56.8% subjects had deletion in exon 19, 42% subjects had mutation in exon 21, and rare mutation in exon 18 was found in 3.4% of total subjects. Demography and clinical characteristics had no significant association with the risk of progressive disease. The median PFS of subjects was 11 months(95%CI: 6.8-15.2 months). There was no statistical difference of PFS between treatment groups.Conclusion Gefitinib, erlotinib, and afatinib have similar effectiveness in advanced stage NSCLC with EGFR mutation positive. Afatinib tends to be associated with longer PFS but further investigation is required.
基金Project(40674071) supported by the National Natural Science Foundation of Chinaproject(KFAS2002-2003) supported by Korea Foundation for Advanced Studies
文摘Based on Fermat’s principle, two-point ray tracing method was studied in three-dimensional structure. By means of first order Taylor’s incomplete series expansion (i.e. no expansion to the length of the ray), a symmetry block tridiagonal matrix equation set was deduced. Further, the positive definiteness of coefficient matrix was discussed, and the positive definiteness was accurately proved in a mathematical way. It assured that the algorithm was well-posed. Associated with iterative method, the solution to ray tracing can be got through step-by-step linearized iteration of the nonlinear problem. An algorithm of the whole path iterative ray tracing method in three-dimensional velocity structure was obtained. This method shows a clear and simple as well as explicit computation formula, which makes ray tracing computation easily applicable in practice. The correction vector is obtained through finding the solution to the positive definite block tridiagonal equation set, which ensures the method is robust convergence. This study offers a new kind of feasible and efficient ray tracing method for three dimensional seismic migration and tomography. Meanwhile, it also provides the prerequisite guarantee to design a fast algorithm.
基金supported by the National High Technology Development Program of China (No. 2003AA302420)the National Major Basic Research Project (No. GT20000264-06) of MOST, China
文摘A series of positive electrodes for Ni/MH battery were fabricated by addition of CoO.The morphology and microstructure of the electrodes were examined by SEM and EDS, and electrochemical behavior was investigated in three-compartment appliances at room temperature.The electrochemical performance of the positive electrodes with CoO was improved. Under the same charge-discharge cycle, the electrodes with CoO showed higher specific capacity, lower charge mean voltage and higher discharge mean voltage. But ...
文摘In this paper, author abtains a group of characteristic conditions for the infinitesimal generators of positive contraction semigroups and stochastic semigroups.Furthermore, Applications of them to linear transport theory are discussed.
文摘An overview of some popular rotary and reciprocating positive displacement( PD) pump types is given with the objective of presenting and comparing the respective sizing relationships and performance features. Reciprocating pumps discussed are the piston and plunger types. Rotary pumps addressed are gear( external and internal),vane,lobe,screw,and liquid ring pumps. To put the relative pump sizes in perspective,attention is fixed on the rotors or reciprocating elements of PD pumps,just as impellers indicate the sizes of rotodynamic pumps. The size of a PD pump is found from a dimensionless combination of displacement flow rate,rotative speed and diameter. The flow rate,head( or pressure rise) and power are related through the component efficiencies. The cavitation coefficient,often close to unity,connects the rotor tip speed or piston speed with the required NPSH,which can also be affected by the pressure rise of the pump due to leakage across the internal clearances. Operational effects due to cavitation,ingestion of gas or abrasives,and viscous and non-Newtonian fluids are discussed.
文摘The academic world has at least nine viewpoints on the Marx's thought in the high school period: devout religious theology,moral theology,liberalism,democracy,utopian socialism,populism,ethical communism,French materialism,the flash of historical materialism,etc. We believe that these views cannot reflect the background of Marx's thoughts in high school. Marx's three high school papers in 1835 reflected the germination of Marx's positive free thoughts in his high school. Marx's positive free thoughts contain a the relatively complete structure of three aspects of the general reason ability of freedom,the special conditions for freedom,and the specific historical form of freedom. The positive free thought in Marx's high school period is finally realized in his communist theory through the his revolution of dialectical materialism and historical materialism.
基金National Natural Science Foundation of China(Grant No.62101138)Shandong Natural Science Foundation(Grant No.ZR2021QD148)+1 种基金Guangdong Natural Science Foundation(Grant No.2022A1515012573)Guangzhou Basic and Applied Basic Research Project(Grant No.202102020701)for providing funds for publishing this paper。
文摘As positioning sensors,edge computation power,and communication technologies continue to develop,a moving agent can now sense its surroundings and communicate with other agents.By receiving spatial information from both its environment and other agents,an agent can use various methods and sensor types to localize itself.With its high flexibility and robustness,collaborative positioning has become a widely used method in both military and civilian applications.This paper introduces the basic fundamental concepts and applications of collaborative positioning,and reviews recent progress in the field based on camera,LiDAR(Light Detection and Ranging),wireless sensor,and their integration.The paper compares the current methods with respect to their sensor type,summarizes their main paradigms,and analyzes their evaluation experiments.Finally,the paper discusses the main challenges and open issues that require further research.
基金the National Natural Science Foundation of China(Grant No.42271436)the Shandong Provincial Natural Science Foundation,China(Grant Nos.ZR2021MD030,ZR2021QD148).
文摘The existing indoor fusion positioning methods based on Pedestrian Dead Reckoning(PDR)and geomagnetic technology have the problems of large initial position error,low sensor accuracy,and geomagnetic mismatch.In this study,a novel indoor fusion positioning approach based on the improved particle filter algorithm by geomagnetic iterative matching is proposed,where Wi-Fi,PDR,and geomagnetic signals are integrated to improve indoor positioning performances.One important contribution is that geomagnetic iterative matching is firstly proposed based on the particle filter algorithm.During the positioning process,an iterative window and a constraint window are introduced to limit the particle generation range and the geomagnetic matching range respectively.The position is corrected several times based on geomagnetic iterative matching in the location correction stage when the pedestrian movement is detected,which made up for the shortage of only one time of geomagnetic correction in the existing particle filter algorithm.In addition,this study also proposes a real-time step detection algorithm based on multi-threshold constraints to judge whether pedestrians are moving,which satisfies the real-time requirement of our fusion positioning approach.Through experimental verification,the average positioning accuracy of the proposed approach reaches 1.59 m,which improves 33.2%compared with the existing particle filter fusion positioning algorithms.
基金supported by the National Natural Science Foundation of China (60702033)Natural Science Foundation of Zhe-jiang Province (Y107440)
文摘An efficient algorithm is proposed for computing the solution to the constrained finite time optimal control （CFTOC） problem for discrete-time piecewise affine （PWA） systems with a quadratic performance index. The maximal positively invariant terminal set, which is feasible and invariant with respect to a feedback control law, is computed as terminal target set and an associated Lyapunov function is chosen as terminal cost. The combination of these two components guarantees constraint satisfaction and closed-loop stability for all time. The proposed algorithm combines a dynamic programming strategy with a multi-parametric quadratic programming solver and basic polyhedral manipulation. A numerical example shows that a larger stabilizable set of states can be obtained by the proposed algorithm than precious work.
基金supported by the National Natural Science Foundation of China under(Grant No.52175531)in part by the Science and Technology Research Program of Chongqing Municipal Education Commission under Grant(Grant Nos.KJQN202000605 and KJZD-M202000602)。
文摘Pedestrian positioning system(PPS)using wearable inertial sensors has wide applications towards various emerging fields such as smart healthcare,emergency rescue,soldier positioning,etc.The performance of traditional PPS is limited by the cumulative error of inertial sensors,complex motion modes of pedestrians,and the low robustness of the multi-sensor collaboration structure.This paper presents a hybrid pedestrian positioning system using the combination of wearable inertial sensors and ultrasonic ranging(H-PPS).A robust two nodes integration structure is developed to adaptively combine the motion data acquired from the single waist-mounted and foot-mounted node,and enhanced by a novel ellipsoid constraint model.In addition,a deep-learning-based walking speed estimator is proposed by considering all the motion features provided by different nodes,which effectively reduces the cumulative error originating from inertial sensors.Finally,a comprehensive data and model dual-driven model is presented to effectively combine the motion data provided by different sensor nodes and walking speed estimator,and multi-level constraints are extracted to further improve the performance of the overall system.Experimental results indicate that the proposed H-PPS significantly improves the performance of the single PPS and outperforms existing algorithms in accuracy index under complex indoor scenarios.
文摘The author studied the existence of positive solutions of the delay logistic difference equation Δ y n=p ny n(1-y τ(n) ), n =0,1,2,.... where { p n } is a sequence of positive real numbers, { τ(n) } is a nondecreasing sequence of integers, τ(n)<n and lim n →∞ τ(n) =∞. A sufficient condition for the existence of positive solutions of the equation was given.
基金Project(10471153) supported by the National Natural Science Foundation of China project supported by the Natural Science Foundation of Central South University
文摘In this paper, we apply a cone theoretic fixed point theorem to obtain sufficient conditions for the existence of multiple positive periodic solutions to the higher-dimensional functional difference equations of the form:x(n+ 1) =A(n)x(n) +λh(n)f(x(n- τ(n))), n∈ Z.
