Deformation can directly reflect the working behavior of the dam,so determining the deformation monitoring control value can effectively monitor the safety of dam operation.The traditional dam deformation monitoring c...Deformation can directly reflect the working behavior of the dam,so determining the deformation monitoring control value can effectively monitor the safety of dam operation.The traditional dam deformation monitoring control value only considers the single measuring point.In order to overcome the limitation,this paper presents a new method to determine the monitoring control value for concrete gravity dam based on the deformations of multi-measuring points.A dam’s comprehensive deformation displacement is determined by the measured values at different measuring points on the positive inverted vertical line and the corresponding weight of eachmeasuring point.The projection pursuit method(PPM)combined with the grey wolf optimization(GWO)algorithm is used to determine the weight of each measuring point according to the spatial correlation distribution characteristics of dam deformation.The peaks over threshold(POT)model based on the extreme value theory is adopted to determine the monitoring control value with the obtained dam comprehensive deformation displacement.In addition,the POTmodel is improved with the automatic threshold determinationmethod based on the 3σcriterion in probability theory and the GWO algorithm,which can avoid subjectivity and randomness in determining the threshold.The results of the engineering application show the feasibility and applicability of the proposed method.展开更多
In this paper, we study the optimal financing problem in the dual model. We introduce a value function which considers both the expected present value of the dividends payout minus the equity issuance and a penalty at...In this paper, we study the optimal financing problem in the dual model. We introduce a value function which considers both the expected present value of the dividends payout minus the equity issuance and a penalty at ruin. In order to get the optimal strategy,two categories of suboptimal models are constructed and studied. Based on these two suboptimal models, we identify the value function and the optimal strategy in the general optimal problem.展开更多
The control value of the deflection of the embedded cylindrical structure, which is the maximum deflection allowed for stability of the cylinder, is a vital quantity of stability calculation. The deflection and the so...The control value of the deflection of the embedded cylindrical structure, which is the maximum deflection allowed for stability of the cylinder, is a vital quantity of stability calculation. The deflection and the soil pressure on the embedded cylinder were investigated by model experiment. When the inclined angle of cylinder is less than or equal to 0.25°, the effective anti-overturning ratio increases gradually and reaches the maximum. When the inclined angle of cylinder is more than 0.25°, the effective anti-overturning ratio decreases gradually. The control value of instability of the cylindrical structure approximates 0.2°. and the bearing stress at the back edge of the cylinder is equal to zero.展开更多
The urea decomposition property at high temperature has been used to control the pH value in the synthesis of layer compounds. The hydrotalcites of Mg-Al and Ni-Al with high crystallinity were synthesized by using th...The urea decomposition property at high temperature has been used to control the pH value in the synthesis of layer compounds. The hydrotalcites of Mg-Al and Ni-Al with high crystallinity were synthesized by using this property.展开更多
Synthesis of polyols from carbon dioxide（CO2） is attractive from the viewpoint of sustainable development of polyurethane industry;it is also interesting to adjust the structure of the CO2-polyols for versatile requ...Synthesis of polyols from carbon dioxide（CO2） is attractive from the viewpoint of sustainable development of polyurethane industry;it is also interesting to adjust the structure of the CO2-polyols for versatile requirement of polyurethane.However,when renewable malonic acid was used as a starter,the copolymerization reaction of CO2 and propylene oxide（PO） was uncontrollable,since it proceeded slowly（13 h） and produced 40.4 wt%of byproduct propylene carbonate（PC） with a low productivity of 0.34kg/g.A careful analysis disclosed that the acid value of the copolymerization medium was the key factor for controlling the copolymerization reaction.Therefore,a preactivation approach was developed to dramatically reduce the acid value to 0.6mg（KOH）/gby homopolymerization of PO into oligo-ether-diol under the initiation of malonic acid,which ensured the controllable copolymerization,where the copolymerization time could be shortened by 77%from 13 to 3 h,the PC content was reduced by 76%from 40.4 wt%to 9.4 wt%,and the productivity increased by 61%from 0.34 to 0.55 kg/g.Moreover,by means of preactivation approach,the molecular weight as well as the carbonate unit content in the CO2-diol was also controllable.展开更多
The problem of state feedback controllers for a class of Takagi-Sugeno （T-S） Lipschitz nonlinear systems is investigated. A simple systematic and useful synthesis method is proposed based on the use of the different...The problem of state feedback controllers for a class of Takagi-Sugeno （T-S） Lipschitz nonlinear systems is investigated. A simple systematic and useful synthesis method is proposed based on the use of the differential mean value theorem （DMVT） and convex theory. The proposed design approach is based on the mean value theorem （MVT） to express the nonlinear error dynamics as a convex combination of known matrices with time varying coefficients as linear parameter varying （LPV） systems. Using the Lyapunov theory, stability conditions are obtained and expressed in terms of linear matrix inequalities （LMIs）. The controller gains are then obtained by solving linear matrix inequalities. The effectiveness of the proposed approach for closed loop-field oriented control （CL-FOC） of permanent magnet synchronous machine （PMSM） drives is demonstrated through an illustrative simulation for the proof of these approaches. Furthermore, an extension for controller design with parameter uncertainties and perturbation performance is discussed.展开更多
To explore the load-bearing performance and the failure patterns of the lining structures,a full-scale loading test on the three-ring staggered assembled shield tunnel segments is carried out through a hydraulic loadi...To explore the load-bearing performance and the failure patterns of the lining structures,a full-scale loading test on the three-ring staggered assembled shield tunnel segments is carried out through a hydraulic loading system.In the experimental study,the segments"internal force,convergence deformation,and displacement,and the bolts'internal force,are analyzed.According to the experimental results,the relationship between internal force and deformation is obtained to determine the residual bearing capacity of the shield tunnel at each stage.Three stages are specified for the evolution of the segment's maximum bending moment during the loading process,in which,the elastic stage is the main and longest stage,in which the bending moment of the segment increases the most.There are two stages for convergence deformation development and segment misalignment development.At the end of loading,the segment's maxi-mum positive and negative convergence values reach 61.22 and-57.69 mm,respectively.Besides,the maximum segment misalignment is 3.67 mm,which occurs in the direction of 90°.The segment cracks when its maximum convergence value reaches 25.03 mm.Moreover,there are signs of fracturing on the waist joint of the segment when its maximum convergence value reaches 32.73 mm.The concrete at the waist joint starts fracturing in pieces when the segment's maximum convergence value reaches 38.93 mm,which is defined as the type of shear failure.Finally,the bearing capacity of shield tunnels during segment failure period can be evaluated by using the corresponding relationship between deformation and internal force.展开更多
In this paper,we present a new method for finding a fixed local-optimal policy for computing the customer lifetime value.The method is developed for a class of ergodic controllable finite Markov chains.We propose an a...In this paper,we present a new method for finding a fixed local-optimal policy for computing the customer lifetime value.The method is developed for a class of ergodic controllable finite Markov chains.We propose an approach based on a non-converging state-value function that fluctuates（increases and decreases） between states of the dynamic process.We prove that it is possible to represent that function in a recursive format using a one-step-ahead fixed-optimal policy.Then,we provide an analytical formula for the numerical realization of the fixed local-optimal strategy.We also present a second approach based on linear programming,to solve the same problem,that implement the c-variable method for making the problem computationally tractable.At the end,we show that these two approaches are related：after a finite number of iterations our proposed approach converges to same result as the linear programming method.We also present a non-traditional approach for ergodicity verification.The validity of the proposed methods is successfully demonstrated theoretically and,by simulated credit-card marketing experiments computing the customer lifetime value for both an optimization and a game theory approach.展开更多
文摘Deformation can directly reflect the working behavior of the dam,so determining the deformation monitoring control value can effectively monitor the safety of dam operation.The traditional dam deformation monitoring control value only considers the single measuring point.In order to overcome the limitation,this paper presents a new method to determine the monitoring control value for concrete gravity dam based on the deformations of multi-measuring points.A dam’s comprehensive deformation displacement is determined by the measured values at different measuring points on the positive inverted vertical line and the corresponding weight of eachmeasuring point.The projection pursuit method(PPM)combined with the grey wolf optimization(GWO)algorithm is used to determine the weight of each measuring point according to the spatial correlation distribution characteristics of dam deformation.The peaks over threshold(POT)model based on the extreme value theory is adopted to determine the monitoring control value with the obtained dam comprehensive deformation displacement.In addition,the POTmodel is improved with the automatic threshold determinationmethod based on the 3σcriterion in probability theory and the GWO algorithm,which can avoid subjectivity and randomness in determining the threshold.The results of the engineering application show the feasibility and applicability of the proposed method.
基金Supported by the National Natural Science Foundation of China(Grant No.11361007)the Guangxi Natural Science Foundation(Grant No.2014GXNSFCA118001)+3 种基金the Fostering Project of Dominant Discipline and Talent Team of Shandong Provincial Higher Education Institutionsthe Fostering Project of Dominant Discipline and Talent Team of SDUFEProject of Shandong Provincial Higher Educational Science and Technology Program(Grant Nos.J15LI01J17KA163)
文摘In this paper, we study the optimal financing problem in the dual model. We introduce a value function which considers both the expected present value of the dividends payout minus the equity issuance and a penalty at ruin. In order to get the optimal strategy,two categories of suboptimal models are constructed and studied. Based on these two suboptimal models, we identify the value function and the optimal strategy in the general optimal problem.
基金SUPPORTED BY THE 9TH NATIONAL FIVE-YEAR PROGRAM OF CHINA( NO. 96-415-03-01).
文摘The control value of the deflection of the embedded cylindrical structure, which is the maximum deflection allowed for stability of the cylinder, is a vital quantity of stability calculation. The deflection and the soil pressure on the embedded cylinder were investigated by model experiment. When the inclined angle of cylinder is less than or equal to 0.25°, the effective anti-overturning ratio increases gradually and reaches the maximum. When the inclined angle of cylinder is more than 0.25°, the effective anti-overturning ratio decreases gradually. The control value of instability of the cylindrical structure approximates 0.2°. and the bearing stress at the back edge of the cylinder is equal to zero.
文摘The urea decomposition property at high temperature has been used to control the pH value in the synthesis of layer compounds. The hydrotalcites of Mg-Al and Ni-Al with high crystallinity were synthesized by using this property.
基金supported by the National Natural Science Foundation of China(51321062,21134002)
文摘Synthesis of polyols from carbon dioxide（CO2） is attractive from the viewpoint of sustainable development of polyurethane industry;it is also interesting to adjust the structure of the CO2-polyols for versatile requirement of polyurethane.However,when renewable malonic acid was used as a starter,the copolymerization reaction of CO2 and propylene oxide（PO） was uncontrollable,since it proceeded slowly（13 h） and produced 40.4 wt%of byproduct propylene carbonate（PC） with a low productivity of 0.34kg/g.A careful analysis disclosed that the acid value of the copolymerization medium was the key factor for controlling the copolymerization reaction.Therefore,a preactivation approach was developed to dramatically reduce the acid value to 0.6mg（KOH）/gby homopolymerization of PO into oligo-ether-diol under the initiation of malonic acid,which ensured the controllable copolymerization,where the copolymerization time could be shortened by 77%from 13 to 3 h,the PC content was reduced by 76%from 40.4 wt%to 9.4 wt%,and the productivity increased by 61%from 0.34 to 0.55 kg/g.Moreover,by means of preactivation approach,the molecular weight as well as the carbonate unit content in the CO2-diol was also controllable.
文摘The problem of state feedback controllers for a class of Takagi-Sugeno （T-S） Lipschitz nonlinear systems is investigated. A simple systematic and useful synthesis method is proposed based on the use of the differential mean value theorem （DMVT） and convex theory. The proposed design approach is based on the mean value theorem （MVT） to express the nonlinear error dynamics as a convex combination of known matrices with time varying coefficients as linear parameter varying （LPV） systems. Using the Lyapunov theory, stability conditions are obtained and expressed in terms of linear matrix inequalities （LMIs）. The controller gains are then obtained by solving linear matrix inequalities. The effectiveness of the proposed approach for closed loop-field oriented control （CL-FOC） of permanent magnet synchronous machine （PMSM） drives is demonstrated through an illustrative simulation for the proof of these approaches. Furthermore, an extension for controller design with parameter uncertainties and perturbation performance is discussed.
基金supported by the General Scientific Research Projects for Agriculture and Social Development in Hangzhou,China(Grant No.20201203B127)the National Natural Science Foundation of China(Grant No.51778576)the Basic Public Welfare Research Projects in Zhejiang Province,China(Grant No.LGF22E080012)。
文摘To explore the load-bearing performance and the failure patterns of the lining structures,a full-scale loading test on the three-ring staggered assembled shield tunnel segments is carried out through a hydraulic loading system.In the experimental study,the segments"internal force,convergence deformation,and displacement,and the bolts'internal force,are analyzed.According to the experimental results,the relationship between internal force and deformation is obtained to determine the residual bearing capacity of the shield tunnel at each stage.Three stages are specified for the evolution of the segment's maximum bending moment during the loading process,in which,the elastic stage is the main and longest stage,in which the bending moment of the segment increases the most.There are two stages for convergence deformation development and segment misalignment development.At the end of loading,the segment's maxi-mum positive and negative convergence values reach 61.22 and-57.69 mm,respectively.Besides,the maximum segment misalignment is 3.67 mm,which occurs in the direction of 90°.The segment cracks when its maximum convergence value reaches 25.03 mm.Moreover,there are signs of fracturing on the waist joint of the segment when its maximum convergence value reaches 32.73 mm.The concrete at the waist joint starts fracturing in pieces when the segment's maximum convergence value reaches 38.93 mm,which is defined as the type of shear failure.Finally,the bearing capacity of shield tunnels during segment failure period can be evaluated by using the corresponding relationship between deformation and internal force.
文摘In this paper,we present a new method for finding a fixed local-optimal policy for computing the customer lifetime value.The method is developed for a class of ergodic controllable finite Markov chains.We propose an approach based on a non-converging state-value function that fluctuates（increases and decreases） between states of the dynamic process.We prove that it is possible to represent that function in a recursive format using a one-step-ahead fixed-optimal policy.Then,we provide an analytical formula for the numerical realization of the fixed local-optimal strategy.We also present a second approach based on linear programming,to solve the same problem,that implement the c-variable method for making the problem computationally tractable.At the end,we show that these two approaches are related：after a finite number of iterations our proposed approach converges to same result as the linear programming method.We also present a non-traditional approach for ergodicity verification.The validity of the proposed methods is successfully demonstrated theoretically and,by simulated credit-card marketing experiments computing the customer lifetime value for both an optimization and a game theory approach.
