Hollow multi-shelled structure(HoMS)is the novel multifunctional structural system,which are con-structed with nanoparticles as structural units,featuring two or more shells,multiple interfaces,and numerous chan-nels ...Hollow multi-shelled structure(HoMS)is the novel multifunctional structural system,which are con-structed with nanoparticles as structural units,featuring two or more shells,multiple interfaces,and numerous chan-nels and demonstrating outstanding properties in energy conversion and mass transfer.In recent years,owing to the breakthroughs in synthetic methods,the diversity of composition and structure of HoMS has been greatly enriched,showing broad application prospects in energy,catalysis,environment and other fields.This review focuses on the research status of HoMS for catalytic applications.Firstly,the new synthesis method for HoMS,namely the sequen-tial templating approach,is introduced from both practical and theoretical perspectives.Then,it summarizes and discusses the structure-performance relationship between the shell structure and catalytic performance.The unique temporal-spatial ordering property of mass transport in HoMS and the major breakthroughs it brings in catalytic applications are discussed.Finally,it looks forward to the opportunities and challenges in the development of HoMS.展开更多
Separated transmit and receive antennas are employed to improve transmit-receive isolation in conventional short-range radars, which greatly increases the antenna size and misaligns of the transmit/receive radiation p...Separated transmit and receive antennas are employed to improve transmit-receive isolation in conventional short-range radars, which greatly increases the antenna size and misaligns of the transmit/receive radiation patterns. In this paper,a dual circularly polarized(CP) monostatic simultaneous transmit and receive(MSTAR) antenna with enhanced isolation is proposed to alleviate the problem. The proposed antenna consists of one sequentially rotating array(SRA), two beamforming networks(BFN), and a combined decoupling structure. The SRA is shared by the transmit and receive to reduce the size of the antenna and to obtain a consistent transmit and receive pattern.The BFN achieve right-hand CP for transmit and left-hand CP for receive. By exploring the combined decoupling structure of uniplanar compact electromagnetic band gap(UC-EBG) and ringshaped defected ground structure(RS-DGS), good transmitreceive isolation is achieved. The proposed antenna prototype is fabricated and experimentally characterized. The simulated and measured results show good agreement. The demonstrate transmit/receive isolation is height than 33 dB, voltage standing wave ratio is lower than 2, axial ratio is lower than 3 dB, and consistent radiation for both transmit and receive is within4.25-4.35 GHz.展开更多
由于网络传输带宽的限制,在网络传输中可能造成数据的丢失.对于同时具有测量数据和控制数据丢失的一类网络控制系统,研究H_2输出反馈控制问题.数据的丢失采用满足Bernoulli分布的二进制随机变量进行表述.利用矩阵不等式方法给出了H_2动...由于网络传输带宽的限制,在网络传输中可能造成数据的丢失.对于同时具有测量数据和控制数据丢失的一类网络控制系统,研究H_2输出反馈控制问题.数据的丢失采用满足Bernoulli分布的二进制随机变量进行表述.利用矩阵不等式方法给出了H_2动态输出反馈控制器存在的充分条件,所设计的控制器使得闭环系统是均方意义下指数稳定并具有给定的H_2性能.采用SLPMM(Sequentially linear programming matrix method)给出相应的控制器求解算法.最后用数值仿真验证了所提出算法的可行性.展开更多
In this article, a new model of establishing flexible and utility bi-bliographic systems dependent on microcomputer or minicomputer is di-scussed and compared with the models of large systems and PC-basedsystems. A pr...In this article, a new model of establishing flexible and utility bi-bliographic systems dependent on microcomputer or minicomputer is di-scussed and compared with the models of large systems and PC-basedsystems. A practical example based on this model, Union Catalog Systemof Serials in Western Languages, is used to show our solution for thedevelopment and utilization of the systems of this kind.展开更多
Gob-area roof rupture movement is a key disturbance factor for gob-side entry retaining.The characteristics of gob-area sequential roof collapse of overlying strata and superposed disturbance mechanism for gob-side en...Gob-area roof rupture movement is a key disturbance factor for gob-side entry retaining.The characteristics of gob-area sequential roof collapse of overlying strata and superposed disturbance mechanism for gob-side entry retaining are obtained via physical simulation and theoretical analysis,in which the scope of disturbed strata is enlarged from main roof to fracture zone.The experiment reveals that as a working face advances,roof strata sequentially collapse from bottom to top and produce multiple disturbances to gob-side entry retaining.Key strata among the overlying strata control each collapse.Main roof subsidence is divided into three stages:flexure subsidence prior to rupture,rotational subsidence during rupture and compressive subsidence after rupture.The amounts of deformation evident in each of the three stages are 15%,55%and 30%,respectively.After the master stratum collapses,main roof subsidence approaches its maximum value.The final span of the key stratum determines the moment and cycling of gob-side entry retaining disturbances.Main roof subsidence influences the load on the filling wall.The sequential roof collapse of overlying strata results in fluctuations in the gob-side entry retaining deformation.Calculation formulae for the final span of the key stratum and the filling wall load are obtained via theoretical analysis.A control method for the stability of the gob-side entry retaining’s surrounding rock is proposed,which includes 3 measures:a“dual-layer”proactive anchorage support,roadside filling with dynamic strength matching and auxiliary support during disturbance.Finally,the gob-side entry retaining of the Xiaoqing mine E1403 working face is presented as an engineering case capable of verifying the validity of the research conclusions.展开更多
The heavy metal(such as Cr,Ni,Cu,Cd,Pb,and Zn)concentration,speciation,and pollution source in 43 sediment samples from the Xiangjiang River were investigated using sequential extraction combined with Pb isotope analy...The heavy metal(such as Cr,Ni,Cu,Cd,Pb,and Zn)concentration,speciation,and pollution source in 43 sediment samples from the Xiangjiang River were investigated using sequential extraction combined with Pb isotope analysis.Cu,Cd,Pb,and Zn concentrations are higher than their background values,while Cr and Ni concentrations are close to those.Sequential extraction demonstrates that heavy metals have different fractions,showing different bioavailabilities.The w(206Pb)/w(207Pb)ratio increases with decreasing bioavailability in the order of exchangeable<carbonate≈Fe-Mn oxides≈organic<residual(p<0.05).Wastewater,dust,and slag from mining and smelting areas,and the residual Pb are assumed to be the primary anthropogenic and natural sources of Pb,respectively.The percentages of anthropogenic Pb in the exchangeable,carbonate,Fe-Mn oxides,and organic fractions are(91.5±16.7)%,(61.1±13.9)%,(57.4±11.1)%,and(55.5±11.2)%,respectively,suggesting a significant input of anthropogenic Pb in these four fractions.展开更多
To improve the performance of the supply chain with one supplier and multiple retailers under deterministic price-sensitive customer demand, an optimal strategy is proposed based on knowledge discovery. First the dece...To improve the performance of the supply chain with one supplier and multiple retailers under deterministic price-sensitive customer demand, an optimal strategy is proposed based on knowledge discovery. First the decentralized system in which the supplier and the retailers are independent, profit-maximizing participants with the supplier acting as a Stackelberg game leader is studied. Numerical examples illustrate the importance of the coordination. The conventional quantity discount mechanism needs to be modified to coordinate the supply chain, so a revenue-sharing contract is proposed to coordinate such supply chain. Lastly, a special decision under certain demand rates is studied. The pricing and replenishment policies can be decided sequentially, which yields much less loss comparing with optimal decision when the demand rates are sufficiently large.展开更多
A two-step leaching method in combination of acid and ethylene diaminetetraacetic acid disodium （EDTA-Na2） was applied to extract metals such as Cd, Cu, Fe, Pb and Zn from a zinc smelting slag. The results show that...A two-step leaching method in combination of acid and ethylene diaminetetraacetic acid disodium （EDTA-Na2） was applied to extract metals such as Cd, Cu, Fe, Pb and Zn from a zinc smelting slag. The results show that the extraction rates of Cd, Cu, Fe and Zn in slag reach 88.3%, 54.1%, 69.6% and 54.7%, respectively, while the extraction rate of Pb is only 0.05% leached with 1.25 mol/L sulfuric acid under the conditions of the ratio of slag to liquid of 100 g/L, 65 ℃ and 120 r/min for 2 h. However, Pb extraction rate from 1.25 mol/L sulfuric acid leached residue reaches as high as 66.5% by using 0.1 mol/L EDTA-Na2 solution. The results indicate that two-step sequential extraction procedure combining 1.25 mol/L sulfuric acid and 0.1 mol/L EDTA-Na2 solution can extensively extract Cd, Cu, Fe, Pb and Zn from zinc smelting slag.展开更多
A Bayesian sequential testing method is proposed to evaluate system reliability index with reliability growth during development.The method develops a reliability growth model of repairable systems for failure censore...A Bayesian sequential testing method is proposed to evaluate system reliability index with reliability growth during development.The method develops a reliability growth model of repairable systems for failure censored test,and figures out the approach to determine the prior distribution of the system failure rate by applying the reliability growth model to incorporate the multistage test data collected from system development.Furthermore,the procedure for the Bayesian sequential testing is derived for the failure rate of the exponential life system,which enables the decision to terminate or continue development test.Finally,a numerical example is given to illustrate the efficiency of the proposed model and procedure.展开更多
An approach for parameter estimation of proportional-integral-derivative(PID) control system using a new nonlinear programming(NLP) algorithm was proposed.SQP/IIPM algorithm is a sequential quadratic programming(SQP) ...An approach for parameter estimation of proportional-integral-derivative(PID) control system using a new nonlinear programming(NLP) algorithm was proposed.SQP/IIPM algorithm is a sequential quadratic programming(SQP) based algorithm that derives its search directions by solving quadratic programming(QP) subproblems via an infeasible interior point method(IIPM) and evaluates step length adaptively via a simple line search and/or a quadratic search algorithm depending on the termination of the IIPM solver.The task of tuning PI/PID parameters for the first-and second-order systems was modeled as constrained NLP problem. SQP/IIPM algorithm was applied to determining the optimum parameters for the PI/PID control systems.To assess the performance of the proposed method,a Matlab simulation of PID controller tuning was conducted to compare the proposed SQP/IIPM algorithm with the gain and phase margin(GPM) method and Ziegler-Nichols(ZN) method.The results reveal that,for both step and impulse response tests,the PI/PID controller using SQP/IIPM optimization algorithm consistently reduce rise time,settling-time and remarkably lower overshoot compared to GPM and ZN methods,and the proposed method improves the robustness and effectiveness of numerical optimization of PID control systems.展开更多
Lysozyme reaction was developed as a novel technique for minimizing the amount of excess sludge in the sequential batch reactor(SBR).In the present work,excess sludge taken from a SBR system was treated by lysozyme re...Lysozyme reaction was developed as a novel technique for minimizing the amount of excess sludge in the sequential batch reactor(SBR).In the present work,excess sludge taken from a SBR system was treated by lysozyme reaction and then returned to the reactor.The quality of the effluent water and characteristics of the activated sludge in the SBR were analyzed to determine the effectiveness of the reduction process.The results show that excess sludge production could be reduced to almost 100%in the first30 d of operation and could be reduced to further by 40%in the succeeding 20 d or so.In these time periods,the average removal efficiencies of the chemical oxygen demand and total nitrogen are 87.38%and 52.78%,respectively,whereas the average total phosphorous in the effluent is nearly 17.18%greater than that of the effluent of the reference system.After 50 d of operation,the sludge floc size is in the range of 20 to 80μm,which was smaller than the size prior to the start of the hydrolysis and the ratio of mixed liquor volatile suspended solids/mixed liquor suspended solids increases from 86%to 90%.展开更多
With a focus on an industrial multivariable system, two subsystems including the flow and the level outputs are analysed and controlled, which have applicability in both real and academic environments. In such a case,...With a focus on an industrial multivariable system, two subsystems including the flow and the level outputs are analysed and controlled, which have applicability in both real and academic environments. In such a case, at first, each subsystem is distinctively represented by its model, since the outcomes point out that the chosen models have the same behavior as corresponding ones. Then, the industrial multivariable system and its presentation are achieved in line with the integration of these subsystems, since the interaction between them can not actually be ignored. To analyze the interaction presented, the Gershgorin bands need to be acquired, where the results are used to modify the system parameters to appropriate values. Subsequently, in the view of modeling results, the control concept in two different techniques including sequential loop closing control(SLCC) scheme and diagonal dominance control(DDC) schemes is proposed to implement on the system through the Profibus network, as long as the OPC(OLE for process control) server is utilized to communicate between the control schemes presented and the multivariable system. The real test scenarios are carried out and the corresponding outcomes in their present forms are acquired. In the same way, the proposed control schemes results are compared with each other, where the real consequences verify the validity of them in the field of the presented industrial multivariable system control.展开更多
A new hybrid optimization algorithm was presented by integrating the gravitational search algorithm （GSA） with the sequential quadratic programming （SQP）, namely GSA-SQP, for solving global optimization problems a...A new hybrid optimization algorithm was presented by integrating the gravitational search algorithm （GSA） with the sequential quadratic programming （SQP）, namely GSA-SQP, for solving global optimization problems and minimization of factor of safety in slope stability analysis. The new algorithm combines the global exploration ability of the GSA to converge rapidly to a near optimum solution. In addition, it uses the accurate local exploitation ability of the SQP to accelerate the search process and find an accurate solution. A set of five well-known benchmark optimization problems was used to validate the performance of the GSA-SQP as a global optimization algorithm and facilitate comparison with the classical GSA. In addition, the effectiveness of the proposed method for slope stability analysis was investigated using three ease studies of slope stability problems from the literature. The factor of safety of earth slopes was evaluated using the Morgenstern-Price method. The numerical experiments demonstrate that the hybrid algorithm converges faster to a significantly more accurate final solution for a variety of benchmark test functions and slope stability problems.展开更多
The distributed hybrid processing optimization problem of non-cooperative targets is an important research direction for future networked air-defense and anti-missile firepower systems. In this paper, the air-defense ...The distributed hybrid processing optimization problem of non-cooperative targets is an important research direction for future networked air-defense and anti-missile firepower systems. In this paper, the air-defense anti-missile targets defense problem is abstracted as a nonconvex constrained combinatorial optimization problem with the optimization objective of maximizing the degree of contribution of the processing scheme to non-cooperative targets, and the constraints mainly consider geographical conditions and anti-missile equipment resources. The grid discretization concept is used to partition the defense area into network nodes, and the overall defense strategy scheme is described as a nonlinear programming problem to solve the minimum defense cost within the maximum defense capability of the defense system network. In the solution of the minimum defense cost problem, the processing scheme, equipment coverage capability, constraints and node cost requirements are characterized, then a nonlinear mathematical model of the non-cooperative target distributed hybrid processing optimization problem is established, and a local optimal solution based on the sequential quadratic programming algorithm is constructed, and the optimal firepower processing scheme is given by using the sequential quadratic programming method containing non-convex quadratic equations and inequality constraints. Finally, the effectiveness of the proposed method is verified by simulation examples.展开更多
In target tracking applications,the Doppler measurement contains information of the target range rate,which has the potential capability to improve the tracking performance.However,the nonlinear degree between the mea...In target tracking applications,the Doppler measurement contains information of the target range rate,which has the potential capability to improve the tracking performance.However,the nonlinear degree between the measurement and the target state increases with the introduction of the Doppler measurement.Therefore,target tracking in the Doppler radar is a nonlinear filtering problem.In order to handle this problem,the Kalman filter form of best linear unbiased estimation(BLUE)with position measurements is proposed,which is combined with the sequential filtering algorithm to handle the Doppler measurement further,where the statistic characteristic of the converted measurement error is calculated based on the predicted information in the sequential filter.Moreover,the algorithm is extended to the maneuvering target tracking case,where the interacting multiple model(IMM)algorithm is used as the basic framework and the model probabilities are updated according to the BLUE position filter and the sequential filter,and the final estimation is a weighted sum of the outputs from the sequential filters and the model probabilities.Simulation results show that compared with existing approaches,the proposed algorithm can realize target tracking with preferable tracking precision and the extended method can achieve effective maneuvering target tracking.展开更多
The problem of sequential fault diagnosis is to construct a diagnosis tree that can isolate the failure sources with minimal test cost. Pervious sequential fault diagnosis strategy generating algorithms only consider ...The problem of sequential fault diagnosis is to construct a diagnosis tree that can isolate the failure sources with minimal test cost. Pervious sequential fault diagnosis strategy generating algorithms only consider the execution cost at application stage, which may result in a solution with poor quality from the view of life cycle cost. Furthermore, due to the fact that uncertain information exists extensively in the real-world systems, the tests are always imperfect. In order to reduce the cost of fault diagnosis in the realistic systems, the sequential fault diagnosis problem with imperfect tests considering life cycle cost is presented and formulated in this work, which is an intractable NP-hard AND/OR decision tree construction problem. An algorithm based on AND/OR graph search is proposed to solve this problem. Heuristic search based on information theory is applied to generate the sub-tree in the algorithm. Some practical issues such as the method to improve the computational efficiency and the diagnosis strategy with multi-outcome tests are discussed. The algorithm is tested and compared with previous algorithms on the simulated systems with different scales and uncertainty. Application on a wheel momentum system of a spacecraft is studied in detail. Both the simulation and application results suggest that the cost of the diagnosis strategy can be reduced significantly by using the proposed algorithm, especially when the placement cost of the tests constitutes a large part of the total cost.展开更多
Testing is the premise and foundation of realizing equipment health management （EHM）. To address the problem that the static periodic test strategy may cause deficient test or excessive test, a dynamic sequential te...Testing is the premise and foundation of realizing equipment health management （EHM）. To address the problem that the static periodic test strategy may cause deficient test or excessive test, a dynamic sequential test strategy （DSTS） for EHM is presented. Considering the situation that equipment health state is not completely observable in reality, a DSTS optimization method based on partially observable semi-Markov decision pro- cess （POSMDP） is proposed. Firstly, an equipment health state degradation model is constructed by Markov process, and the control limit maintenance policy is also introduced. Secondly, POSMDP is formulated in great detail. And then, POSMDP is converted to completely observable belief semi-Markov decision process （BSMDP） through belief state. The optimal equation and the corresponding optimal DSTS, which minimize the long-run ex- pected average cost per unit time, are obtained with BSMDP. The results of application in complex equipment show that the proposed DSTS is feasible and effective.展开更多
文摘Hollow multi-shelled structure(HoMS)is the novel multifunctional structural system,which are con-structed with nanoparticles as structural units,featuring two or more shells,multiple interfaces,and numerous chan-nels and demonstrating outstanding properties in energy conversion and mass transfer.In recent years,owing to the breakthroughs in synthetic methods,the diversity of composition and structure of HoMS has been greatly enriched,showing broad application prospects in energy,catalysis,environment and other fields.This review focuses on the research status of HoMS for catalytic applications.Firstly,the new synthesis method for HoMS,namely the sequen-tial templating approach,is introduced from both practical and theoretical perspectives.Then,it summarizes and discusses the structure-performance relationship between the shell structure and catalytic performance.The unique temporal-spatial ordering property of mass transport in HoMS and the major breakthroughs it brings in catalytic applications are discussed.Finally,it looks forward to the opportunities and challenges in the development of HoMS.
基金supported by Guangdong Natural Science Foundation(2019A1515011622)Guangdong Provincial Laboratory of Southern Marine Science and Engineering (Zhuhai)(SML2021SP407)。
文摘Separated transmit and receive antennas are employed to improve transmit-receive isolation in conventional short-range radars, which greatly increases the antenna size and misaligns of the transmit/receive radiation patterns. In this paper,a dual circularly polarized(CP) monostatic simultaneous transmit and receive(MSTAR) antenna with enhanced isolation is proposed to alleviate the problem. The proposed antenna consists of one sequentially rotating array(SRA), two beamforming networks(BFN), and a combined decoupling structure. The SRA is shared by the transmit and receive to reduce the size of the antenna and to obtain a consistent transmit and receive pattern.The BFN achieve right-hand CP for transmit and left-hand CP for receive. By exploring the combined decoupling structure of uniplanar compact electromagnetic band gap(UC-EBG) and ringshaped defected ground structure(RS-DGS), good transmitreceive isolation is achieved. The proposed antenna prototype is fabricated and experimentally characterized. The simulated and measured results show good agreement. The demonstrate transmit/receive isolation is height than 33 dB, voltage standing wave ratio is lower than 2, axial ratio is lower than 3 dB, and consistent radiation for both transmit and receive is within4.25-4.35 GHz.
文摘由于网络传输带宽的限制,在网络传输中可能造成数据的丢失.对于同时具有测量数据和控制数据丢失的一类网络控制系统,研究H_2输出反馈控制问题.数据的丢失采用满足Bernoulli分布的二进制随机变量进行表述.利用矩阵不等式方法给出了H_2动态输出反馈控制器存在的充分条件,所设计的控制器使得闭环系统是均方意义下指数稳定并具有给定的H_2性能.采用SLPMM(Sequentially linear programming matrix method)给出相应的控制器求解算法.最后用数值仿真验证了所提出算法的可行性.
文摘In this article, a new model of establishing flexible and utility bi-bliographic systems dependent on microcomputer or minicomputer is di-scussed and compared with the models of large systems and PC-basedsystems. A practical example based on this model, Union Catalog Systemof Serials in Western Languages, is used to show our solution for thedevelopment and utilization of the systems of this kind.
基金Project(51404251)supported by the National Natural Science Foundation of ChinaProject(BK20140198)supported by the Natural Science Foundation of Jiangsu Province,China+1 种基金Project(PPZY2015A046)supported by the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions,ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Gob-area roof rupture movement is a key disturbance factor for gob-side entry retaining.The characteristics of gob-area sequential roof collapse of overlying strata and superposed disturbance mechanism for gob-side entry retaining are obtained via physical simulation and theoretical analysis,in which the scope of disturbed strata is enlarged from main roof to fracture zone.The experiment reveals that as a working face advances,roof strata sequentially collapse from bottom to top and produce multiple disturbances to gob-side entry retaining.Key strata among the overlying strata control each collapse.Main roof subsidence is divided into three stages:flexure subsidence prior to rupture,rotational subsidence during rupture and compressive subsidence after rupture.The amounts of deformation evident in each of the three stages are 15%,55%and 30%,respectively.After the master stratum collapses,main roof subsidence approaches its maximum value.The final span of the key stratum determines the moment and cycling of gob-side entry retaining disturbances.Main roof subsidence influences the load on the filling wall.The sequential roof collapse of overlying strata results in fluctuations in the gob-side entry retaining deformation.Calculation formulae for the final span of the key stratum and the filling wall load are obtained via theoretical analysis.A control method for the stability of the gob-side entry retaining’s surrounding rock is proposed,which includes 3 measures:a“dual-layer”proactive anchorage support,roadside filling with dynamic strength matching and auxiliary support during disturbance.Finally,the gob-side entry retaining of the Xiaoqing mine E1403 working face is presented as an engineering case capable of verifying the validity of the research conclusions.
基金Project(2009ZX07212-001)supported by the Major Science and Technology Program for Water Pollution Control and Treatment of ChinaProject(51079002)supported by the National Natural Science Foundation of China
文摘The heavy metal(such as Cr,Ni,Cu,Cd,Pb,and Zn)concentration,speciation,and pollution source in 43 sediment samples from the Xiangjiang River were investigated using sequential extraction combined with Pb isotope analysis.Cu,Cd,Pb,and Zn concentrations are higher than their background values,while Cr and Ni concentrations are close to those.Sequential extraction demonstrates that heavy metals have different fractions,showing different bioavailabilities.The w(206Pb)/w(207Pb)ratio increases with decreasing bioavailability in the order of exchangeable<carbonate≈Fe-Mn oxides≈organic<residual(p<0.05).Wastewater,dust,and slag from mining and smelting areas,and the residual Pb are assumed to be the primary anthropogenic and natural sources of Pb,respectively.The percentages of anthropogenic Pb in the exchangeable,carbonate,Fe-Mn oxides,and organic fractions are(91.5±16.7)%,(61.1±13.9)%,(57.4±11.1)%,and(55.5±11.2)%,respectively,suggesting a significant input of anthropogenic Pb in these four fractions.
基金the National Natural Science Foundation of China (70471034)the Talent Foundation of Nanjing University of Aeronautics and Astronautics (s0670-082).
文摘To improve the performance of the supply chain with one supplier and multiple retailers under deterministic price-sensitive customer demand, an optimal strategy is proposed based on knowledge discovery. First the decentralized system in which the supplier and the retailers are independent, profit-maximizing participants with the supplier acting as a Stackelberg game leader is studied. Numerical examples illustrate the importance of the coordination. The conventional quantity discount mechanism needs to be modified to coordinate the supply chain, so a revenue-sharing contract is proposed to coordinate such supply chain. Lastly, a special decision under certain demand rates is studied. The pricing and replenishment policies can be decided sequentially, which yields much less loss comparing with optimal decision when the demand rates are sufficiently large.
基金Project(2011SK3262) supported by Science and Technology Program of Hunan Province,China
文摘A two-step leaching method in combination of acid and ethylene diaminetetraacetic acid disodium （EDTA-Na2） was applied to extract metals such as Cd, Cu, Fe, Pb and Zn from a zinc smelting slag. The results show that the extraction rates of Cd, Cu, Fe and Zn in slag reach 88.3%, 54.1%, 69.6% and 54.7%, respectively, while the extraction rate of Pb is only 0.05% leached with 1.25 mol/L sulfuric acid under the conditions of the ratio of slag to liquid of 100 g/L, 65 ℃ and 120 r/min for 2 h. However, Pb extraction rate from 1.25 mol/L sulfuric acid leached residue reaches as high as 66.5% by using 0.1 mol/L EDTA-Na2 solution. The results indicate that two-step sequential extraction procedure combining 1.25 mol/L sulfuric acid and 0.1 mol/L EDTA-Na2 solution can extensively extract Cd, Cu, Fe, Pb and Zn from zinc smelting slag.
基金supported by the National Natural Science Foundation of China (70571083)the Research Fund for the Doctoral Program of Higher Education of China (20094307110013)
文摘A Bayesian sequential testing method is proposed to evaluate system reliability index with reliability growth during development.The method develops a reliability growth model of repairable systems for failure censored test,and figures out the approach to determine the prior distribution of the system failure rate by applying the reliability growth model to incorporate the multistage test data collected from system development.Furthermore,the procedure for the Bayesian sequential testing is derived for the failure rate of the exponential life system,which enables the decision to terminate or continue development test.Finally,a numerical example is given to illustrate the efficiency of the proposed model and procedure.
基金Project(60874070) supported by the National Natural Science Foundation of ChinaProject(20070533131) supported by the National Research Foundation for the Doctoral Program of Higher Education of ChinaProject supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China
文摘An approach for parameter estimation of proportional-integral-derivative(PID) control system using a new nonlinear programming(NLP) algorithm was proposed.SQP/IIPM algorithm is a sequential quadratic programming(SQP) based algorithm that derives its search directions by solving quadratic programming(QP) subproblems via an infeasible interior point method(IIPM) and evaluates step length adaptively via a simple line search and/or a quadratic search algorithm depending on the termination of the IIPM solver.The task of tuning PI/PID parameters for the first-and second-order systems was modeled as constrained NLP problem. SQP/IIPM algorithm was applied to determining the optimum parameters for the PI/PID control systems.To assess the performance of the proposed method,a Matlab simulation of PID controller tuning was conducted to compare the proposed SQP/IIPM algorithm with the gain and phase margin(GPM) method and Ziegler-Nichols(ZN) method.The results reveal that,for both step and impulse response tests,the PI/PID controller using SQP/IIPM optimization algorithm consistently reduce rise time,settling-time and remarkably lower overshoot compared to GPM and ZN methods,and the proposed method improves the robustness and effectiveness of numerical optimization of PID control systems.
基金Project(51078130)supported by the National Natural Science Foundation of ChinaProject(10C0419)supported by the the Education Department of Hunan Province,China
文摘Lysozyme reaction was developed as a novel technique for minimizing the amount of excess sludge in the sequential batch reactor(SBR).In the present work,excess sludge taken from a SBR system was treated by lysozyme reaction and then returned to the reactor.The quality of the effluent water and characteristics of the activated sludge in the SBR were analyzed to determine the effectiveness of the reduction process.The results show that excess sludge production could be reduced to almost 100%in the first30 d of operation and could be reduced to further by 40%in the succeeding 20 d or so.In these time periods,the average removal efficiencies of the chemical oxygen demand and total nitrogen are 87.38%and 52.78%,respectively,whereas the average total phosphorous in the effluent is nearly 17.18%greater than that of the effluent of the reference system.After 50 d of operation,the sludge floc size is in the range of 20 to 80μm,which was smaller than the size prior to the start of the hydrolysis and the ratio of mixed liquor volatile suspended solids/mixed liquor suspended solids increases from 86%to 90%.
文摘With a focus on an industrial multivariable system, two subsystems including the flow and the level outputs are analysed and controlled, which have applicability in both real and academic environments. In such a case, at first, each subsystem is distinctively represented by its model, since the outcomes point out that the chosen models have the same behavior as corresponding ones. Then, the industrial multivariable system and its presentation are achieved in line with the integration of these subsystems, since the interaction between them can not actually be ignored. To analyze the interaction presented, the Gershgorin bands need to be acquired, where the results are used to modify the system parameters to appropriate values. Subsequently, in the view of modeling results, the control concept in two different techniques including sequential loop closing control(SLCC) scheme and diagonal dominance control(DDC) schemes is proposed to implement on the system through the Profibus network, as long as the OPC(OLE for process control) server is utilized to communicate between the control schemes presented and the multivariable system. The real test scenarios are carried out and the corresponding outcomes in their present forms are acquired. In the same way, the proposed control schemes results are compared with each other, where the real consequences verify the validity of them in the field of the presented industrial multivariable system control.
文摘A new hybrid optimization algorithm was presented by integrating the gravitational search algorithm （GSA） with the sequential quadratic programming （SQP）, namely GSA-SQP, for solving global optimization problems and minimization of factor of safety in slope stability analysis. The new algorithm combines the global exploration ability of the GSA to converge rapidly to a near optimum solution. In addition, it uses the accurate local exploitation ability of the SQP to accelerate the search process and find an accurate solution. A set of five well-known benchmark optimization problems was used to validate the performance of the GSA-SQP as a global optimization algorithm and facilitate comparison with the classical GSA. In addition, the effectiveness of the proposed method for slope stability analysis was investigated using three ease studies of slope stability problems from the literature. The factor of safety of earth slopes was evaluated using the Morgenstern-Price method. The numerical experiments demonstrate that the hybrid algorithm converges faster to a significantly more accurate final solution for a variety of benchmark test functions and slope stability problems.
基金supported by the National Natural Science Foundation of China (61903025)the Fundamental Research Funds for the Cent ral Universities (FRF-IDRY-20-013)。
文摘The distributed hybrid processing optimization problem of non-cooperative targets is an important research direction for future networked air-defense and anti-missile firepower systems. In this paper, the air-defense anti-missile targets defense problem is abstracted as a nonconvex constrained combinatorial optimization problem with the optimization objective of maximizing the degree of contribution of the processing scheme to non-cooperative targets, and the constraints mainly consider geographical conditions and anti-missile equipment resources. The grid discretization concept is used to partition the defense area into network nodes, and the overall defense strategy scheme is described as a nonlinear programming problem to solve the minimum defense cost within the maximum defense capability of the defense system network. In the solution of the minimum defense cost problem, the processing scheme, equipment coverage capability, constraints and node cost requirements are characterized, then a nonlinear mathematical model of the non-cooperative target distributed hybrid processing optimization problem is established, and a local optimal solution based on the sequential quadratic programming algorithm is constructed, and the optimal firepower processing scheme is given by using the sequential quadratic programming method containing non-convex quadratic equations and inequality constraints. Finally, the effectiveness of the proposed method is verified by simulation examples.
基金This work was supported by the Basic Research Operation Foundation for Central University(ZYGX2016J039).
文摘In target tracking applications,the Doppler measurement contains information of the target range rate,which has the potential capability to improve the tracking performance.However,the nonlinear degree between the measurement and the target state increases with the introduction of the Doppler measurement.Therefore,target tracking in the Doppler radar is a nonlinear filtering problem.In order to handle this problem,the Kalman filter form of best linear unbiased estimation(BLUE)with position measurements is proposed,which is combined with the sequential filtering algorithm to handle the Doppler measurement further,where the statistic characteristic of the converted measurement error is calculated based on the predicted information in the sequential filter.Moreover,the algorithm is extended to the maneuvering target tracking case,where the interacting multiple model(IMM)algorithm is used as the basic framework and the model probabilities are updated according to the BLUE position filter and the sequential filter,and the final estimation is a weighted sum of the outputs from the sequential filters and the model probabilities.Simulation results show that compared with existing approaches,the proposed algorithm can realize target tracking with preferable tracking precision and the extended method can achieve effective maneuvering target tracking.
基金Project(C1320063131)supported by China Civil Space Foundation
文摘The problem of sequential fault diagnosis is to construct a diagnosis tree that can isolate the failure sources with minimal test cost. Pervious sequential fault diagnosis strategy generating algorithms only consider the execution cost at application stage, which may result in a solution with poor quality from the view of life cycle cost. Furthermore, due to the fact that uncertain information exists extensively in the real-world systems, the tests are always imperfect. In order to reduce the cost of fault diagnosis in the realistic systems, the sequential fault diagnosis problem with imperfect tests considering life cycle cost is presented and formulated in this work, which is an intractable NP-hard AND/OR decision tree construction problem. An algorithm based on AND/OR graph search is proposed to solve this problem. Heuristic search based on information theory is applied to generate the sub-tree in the algorithm. Some practical issues such as the method to improve the computational efficiency and the diagnosis strategy with multi-outcome tests are discussed. The algorithm is tested and compared with previous algorithms on the simulated systems with different scales and uncertainty. Application on a wheel momentum system of a spacecraft is studied in detail. Both the simulation and application results suggest that the cost of the diagnosis strategy can be reduced significantly by using the proposed algorithm, especially when the placement cost of the tests constitutes a large part of the total cost.
基金supported by the National Natural Science Foundation of China (51175502)
文摘Testing is the premise and foundation of realizing equipment health management （EHM）. To address the problem that the static periodic test strategy may cause deficient test or excessive test, a dynamic sequential test strategy （DSTS） for EHM is presented. Considering the situation that equipment health state is not completely observable in reality, a DSTS optimization method based on partially observable semi-Markov decision pro- cess （POSMDP） is proposed. Firstly, an equipment health state degradation model is constructed by Markov process, and the control limit maintenance policy is also introduced. Secondly, POSMDP is formulated in great detail. And then, POSMDP is converted to completely observable belief semi-Markov decision process （BSMDP） through belief state. The optimal equation and the corresponding optimal DSTS, which minimize the long-run ex- pected average cost per unit time, are obtained with BSMDP. The results of application in complex equipment show that the proposed DSTS is feasible and effective.
