The evolutionary strategy with a dynamic weighting schedule is proposed to find all the compromised solutions of the multi-objective integrated structure and control optimization problem, where the optimal system perf...The evolutionary strategy with a dynamic weighting schedule is proposed to find all the compromised solutions of the multi-objective integrated structure and control optimization problem, where the optimal system performance and control cost are defined by H2 or H∞ norms. During this optimization process, the weights are varying with the increasing generation instead of fixed values. The proposed strategy together with the linear matrix inequality （LMI） or the Riccati controller design method can find a series of uniformly distributed nondominated solutions in a single run. Therefore, this method can greatly reduce the computation intensity of the integrated optimization problem compared with the weight-based single objective genetic algorithm. Active automotive suspension is adopted as an example to illustrate the effectiveness of the proposed method.展开更多
Graphene(GR),a single‐layer carbon sheet with a hexagonal packed lattice structure,has displayed attractive potential and demonstrably become the research focus in artificial photocatalysis due to its enchanting prop...Graphene(GR),a single‐layer carbon sheet with a hexagonal packed lattice structure,has displayed attractive potential and demonstrably become the research focus in artificial photocatalysis due to its enchanting properties in enhancing light absorption,electron transfer dynamics,and surface reactions.Currently,numerous efforts have shown that the properties of GR,which are closely correlated to the photocatalytic performance of GR‐based composites are significantly affected by the synthesis methods.Herein,we first introduce the optimization strategies of GR‐based hybrids and then elaborate the synthesis of GR‐based composite photocatalysts oriented by manifold roles of GR in photoredox catalysis,containing photoelectron mediator and acceptor,improving adsorption capacity,regulating light absorption range and intensity,as well as macromolecular photosensitizer.Beyond that,a brief outlook on the challenges in this burgeoning research field and potential evolution strategies for enhancing the photoactivity of GR‐based hybrids is presented and we anticipate that this review could provide some enlightenments for the rational construction and application of multifunctional GR‐based composite photocatalysts.展开更多
To alleviate the heavy load of massive alarm on operators, alarm threshold in chemical processes was optimized with principal component analysis(PCA) weight and Johnson transformation in this paper. First, few variabl...To alleviate the heavy load of massive alarm on operators, alarm threshold in chemical processes was optimized with principal component analysis(PCA) weight and Johnson transformation in this paper. First, few variables that have high PCA weight factors are chosen as key variables. Given a total alarm frequency to these variables initially, the allowed alarm number for each variable is determined according to their sampling time and weight factors. Their alarm threshold and then control limit percentage are determined successively. The control limit percentage of non-key variables is determined with 3σ method alternatively. Second, raw data are transformed into normal distribution data with Johnson function for all variables before updating their alarm thresholds via inverse transformation of obtained control limit percentage. Alarm thresholds are optimized by iterating this process until the calculated alarm frequency reaches standard level(normally one alarm per minute). Finally,variables and their alarm thresholds are visualized in parallel coordinate to depict their variation trends concisely and clearly. Case studies on a simulated industrial atmospheric-vacuum crude distillation demonstrate that the proposed alarm threshold optimization strategy can effectively reduce false alarm rate in chemical processes.展开更多
According to the complex nonlinear relationship between gas emission and its effect factors, and the shortcomings that basic colony algorithm is slow, prone to early maturity and stagnation during the search, we intro...According to the complex nonlinear relationship between gas emission and its effect factors, and the shortcomings that basic colony algorithm is slow, prone to early maturity and stagnation during the search, we introduced a hybrid optimization strategy into a max-rain ant colony algorithm, then use this improved ant colony algorithm to estimate the scope of RBF network parameters. According to the amount of pheromone of discrete points, the authors obtained from the interval of net- work parameters, ants optimize network parameters. Finally, local spatial expansion is introduced to get further optimization of the network. Therefore, we obtain a better time efficiency and solution efficiency optimization model called hybrid improved max-min ant system （H1-MMAS）. Simulation experiments, using these theory to predict the gas emission from the working face, show that the proposed method have high prediction feasibility and it is an effective method to predict gas emission.展开更多
One measurement-based dynamic optimization scheme can achieve optimality under uncertainties by tracking the necessary condition of optimality(NCO-tracking), with a basic assumption that the solution model remains inv...One measurement-based dynamic optimization scheme can achieve optimality under uncertainties by tracking the necessary condition of optimality(NCO-tracking), with a basic assumption that the solution model remains invariant in the presence of all kinds of uncertainties. This assumption is not satisfied in some cases and the standard NCO-tracking scheme is infeasible. In this paper, a novel two-level NCO-tracking scheme is proposed to deal with this problem. A heuristic criterion is given for triggering outer level compensation procedure to update the solution model once any change is detected via online measurement and estimation. The standard NCO-tracking process is carried out at the inner level based on the updated solution model. The proposed approach is illustrated via a bioreactor in penicillin fermentation process.展开更多
The evolutionary algorithm, a subset of computational intelligence techniques, is a generic population-based stochastic optimization algorithm which uses a mechanism motivated by biological concepts. Bio-inspired comp...The evolutionary algorithm, a subset of computational intelligence techniques, is a generic population-based stochastic optimization algorithm which uses a mechanism motivated by biological concepts. Bio-inspired computing can implement successful optimization methods and adaptation approaches, which are inspired by the natural evolution and collective behavior observed in species, respectively. Although all the meta-heuristic algorithms have different inspirational sources, their objective is to find the optimum(minimum or maximum), which is problem-specific. We propose and evaluate a novel synergistic fibroblast optimization(SFO) algorithm, which exhibits the behavior of a fibroblast cellular organism in the dermal wound-healing process. Various characteristics of benchmark suites are applied to validate the robustness, reliability, generalization, and comprehensibility of SFO in diverse and complex situations. The encouraging results suggest that the collaborative and self-adaptive behaviors of fibroblasts have intellectually found the optimum solution with several different features that can improve the effectiveness of optimization strategies for solving non-linear complicated problems.展开更多
The unmodified graphitic carbon nitride(g-C_3N_4) suffers from low photocatalytic activity because of the unfavourable structure.In the present work,we reported a simple self-structural modification strategy to optimi...The unmodified graphitic carbon nitride(g-C_3N_4) suffers from low photocatalytic activity because of the unfavourable structure.In the present work,we reported a simple self-structural modification strategy to optimize the microstructure of g-C_3N_4 and obtained graphene-like g-C_3N_4 nanosheets with porous structure.In contrast to traditional thermal pyrolysis preparation of g-C_3N_4,the present thermal condensation was improved via pyrolysis of thiourea in an alumina crucible without a cover,followed by secondary heat treatment.The popcorn-like formation and layer-by-layer thermal exfoliation of graphene-like porous g-C_3N_4 was proposed to explain the formation mechanism.The photocatalytic removal performance of both NO and NO_2 with the graphene-like porous g-C_3N_4 for was significantly enhanced by selfstructural modification.Trapping experiments and in-situ diffuse reflectance infrared fourier transform spectroscopy(DRIFTS) measurement were conducted to detect the active species during photocatalysis and the conversion pathway of g-C_3N_4 photocatalysis for NO_x purification was revealed.The photocatalytic activity of graphene-like porous g-C_3N_4 was highly enhanced due to the improved charge separation and increased oxidation capacity of the ·O_2^- radicals and holes.This work could not only provide a novel self-structural modification for design of highly efficient photocatalysts,but also offer new insights into the mechanistic understanding of g-C_3N_4 photocatalysis.展开更多
VOF method which consists in transporting a discontinuous marker variable is widely used to capture the free surface in computational fluid dynamics.There is numerical dissipation in simulations involving the transpor...VOF method which consists in transporting a discontinuous marker variable is widely used to capture the free surface in computational fluid dynamics.There is numerical dissipation in simulations involving the transport of the marker.Numerical dissipation makes the free surface lose its physical nature.A free surface sharpening strategy based on optimization method is presented in the paper.The strategy can keep the location of the free surface and local mass conservation at both time,and can also keep free surface in a constant width.It is independent on the types of solvers and meshes.Two famous cases were chosen for verifying the free surface sharpening strategy performance.Results show that the strategy has a very good performance on keeping local mass conservation.The efficiency of prediction of the free surface is improved by applying the strategy.Accurate modeling of flow details such as drops can also be captured by this method.展开更多
文摘The evolutionary strategy with a dynamic weighting schedule is proposed to find all the compromised solutions of the multi-objective integrated structure and control optimization problem, where the optimal system performance and control cost are defined by H2 or H∞ norms. During this optimization process, the weights are varying with the increasing generation instead of fixed values. The proposed strategy together with the linear matrix inequality （LMI） or the Riccati controller design method can find a series of uniformly distributed nondominated solutions in a single run. Therefore, this method can greatly reduce the computation intensity of the integrated optimization problem compared with the weight-based single objective genetic algorithm. Active automotive suspension is adopted as an example to illustrate the effectiveness of the proposed method.
文摘Graphene(GR),a single‐layer carbon sheet with a hexagonal packed lattice structure,has displayed attractive potential and demonstrably become the research focus in artificial photocatalysis due to its enchanting properties in enhancing light absorption,electron transfer dynamics,and surface reactions.Currently,numerous efforts have shown that the properties of GR,which are closely correlated to the photocatalytic performance of GR‐based composites are significantly affected by the synthesis methods.Herein,we first introduce the optimization strategies of GR‐based hybrids and then elaborate the synthesis of GR‐based composite photocatalysts oriented by manifold roles of GR in photoredox catalysis,containing photoelectron mediator and acceptor,improving adsorption capacity,regulating light absorption range and intensity,as well as macromolecular photosensitizer.Beyond that,a brief outlook on the challenges in this burgeoning research field and potential evolution strategies for enhancing the photoactivity of GR‐based hybrids is presented and we anticipate that this review could provide some enlightenments for the rational construction and application of multifunctional GR‐based composite photocatalysts.
基金Supported by the National Natural Science Foundation of China(21576143)
文摘To alleviate the heavy load of massive alarm on operators, alarm threshold in chemical processes was optimized with principal component analysis(PCA) weight and Johnson transformation in this paper. First, few variables that have high PCA weight factors are chosen as key variables. Given a total alarm frequency to these variables initially, the allowed alarm number for each variable is determined according to their sampling time and weight factors. Their alarm threshold and then control limit percentage are determined successively. The control limit percentage of non-key variables is determined with 3σ method alternatively. Second, raw data are transformed into normal distribution data with Johnson function for all variables before updating their alarm thresholds via inverse transformation of obtained control limit percentage. Alarm thresholds are optimized by iterating this process until the calculated alarm frequency reaches standard level(normally one alarm per minute). Finally,variables and their alarm thresholds are visualized in parallel coordinate to depict their variation trends concisely and clearly. Case studies on a simulated industrial atmospheric-vacuum crude distillation demonstrate that the proposed alarm threshold optimization strategy can effectively reduce false alarm rate in chemical processes.
基金Supported by the National Natural Science Foundation （70971059） the Liaoning Provincial Programs lbr Science and Technology Development （2011229011）
文摘According to the complex nonlinear relationship between gas emission and its effect factors, and the shortcomings that basic colony algorithm is slow, prone to early maturity and stagnation during the search, we introduced a hybrid optimization strategy into a max-rain ant colony algorithm, then use this improved ant colony algorithm to estimate the scope of RBF network parameters. According to the amount of pheromone of discrete points, the authors obtained from the interval of net- work parameters, ants optimize network parameters. Finally, local spatial expansion is introduced to get further optimization of the network. Therefore, we obtain a better time efficiency and solution efficiency optimization model called hybrid improved max-min ant system （H1-MMAS）. Simulation experiments, using these theory to predict the gas emission from the working face, show that the proposed method have high prediction feasibility and it is an effective method to predict gas emission.
基金Supported by the National Natural Science Foundation of China(61174114)the Research Fund for the Doctoral Program of Higher Education in China(20120101130016)the Scholarship Award for Excellent Doctoral Student granted by Ministry of Education
文摘One measurement-based dynamic optimization scheme can achieve optimality under uncertainties by tracking the necessary condition of optimality(NCO-tracking), with a basic assumption that the solution model remains invariant in the presence of all kinds of uncertainties. This assumption is not satisfied in some cases and the standard NCO-tracking scheme is infeasible. In this paper, a novel two-level NCO-tracking scheme is proposed to deal with this problem. A heuristic criterion is given for triggering outer level compensation procedure to update the solution model once any change is detected via online measurement and estimation. The standard NCO-tracking process is carried out at the inner level based on the updated solution model. The proposed approach is illustrated via a bioreactor in penicillin fermentation process.
文摘The evolutionary algorithm, a subset of computational intelligence techniques, is a generic population-based stochastic optimization algorithm which uses a mechanism motivated by biological concepts. Bio-inspired computing can implement successful optimization methods and adaptation approaches, which are inspired by the natural evolution and collective behavior observed in species, respectively. Although all the meta-heuristic algorithms have different inspirational sources, their objective is to find the optimum(minimum or maximum), which is problem-specific. We propose and evaluate a novel synergistic fibroblast optimization(SFO) algorithm, which exhibits the behavior of a fibroblast cellular organism in the dermal wound-healing process. Various characteristics of benchmark suites are applied to validate the robustness, reliability, generalization, and comprehensibility of SFO in diverse and complex situations. The encouraging results suggest that the collaborative and self-adaptive behaviors of fibroblasts have intellectually found the optimum solution with several different features that can improve the effectiveness of optimization strategies for solving non-linear complicated problems.
基金supported by the National Natural Science Foundation of China(51478070,21501016 and 21777011)the National Key R&D Program of China(2016YFC0204702)+3 种基金the Innovative Research Team of Chongqing(CXTDG201602014)the Natural Science Foundation of Chongqing(cstc2016jcyj A0481,cstc2017jcyj BX0052)the Early Career Scheme(ECS 809813) from Hong Kongthe Internal Research Grant from Hong Kong Institute of Education(R3588)
文摘The unmodified graphitic carbon nitride(g-C_3N_4) suffers from low photocatalytic activity because of the unfavourable structure.In the present work,we reported a simple self-structural modification strategy to optimize the microstructure of g-C_3N_4 and obtained graphene-like g-C_3N_4 nanosheets with porous structure.In contrast to traditional thermal pyrolysis preparation of g-C_3N_4,the present thermal condensation was improved via pyrolysis of thiourea in an alumina crucible without a cover,followed by secondary heat treatment.The popcorn-like formation and layer-by-layer thermal exfoliation of graphene-like porous g-C_3N_4 was proposed to explain the formation mechanism.The photocatalytic removal performance of both NO and NO_2 with the graphene-like porous g-C_3N_4 for was significantly enhanced by selfstructural modification.Trapping experiments and in-situ diffuse reflectance infrared fourier transform spectroscopy(DRIFTS) measurement were conducted to detect the active species during photocatalysis and the conversion pathway of g-C_3N_4 photocatalysis for NO_x purification was revealed.The photocatalytic activity of graphene-like porous g-C_3N_4 was highly enhanced due to the improved charge separation and increased oxidation capacity of the ·O_2^- radicals and holes.This work could not only provide a novel self-structural modification for design of highly efficient photocatalysts,but also offer new insights into the mechanistic understanding of g-C_3N_4 photocatalysis.
基金funded by National Natural Science Foundation of China,Grant number:51176012
文摘VOF method which consists in transporting a discontinuous marker variable is widely used to capture the free surface in computational fluid dynamics.There is numerical dissipation in simulations involving the transport of the marker.Numerical dissipation makes the free surface lose its physical nature.A free surface sharpening strategy based on optimization method is presented in the paper.The strategy can keep the location of the free surface and local mass conservation at both time,and can also keep free surface in a constant width.It is independent on the types of solvers and meshes.Two famous cases were chosen for verifying the free surface sharpening strategy performance.Results show that the strategy has a very good performance on keeping local mass conservation.The efficiency of prediction of the free surface is improved by applying the strategy.Accurate modeling of flow details such as drops can also be captured by this method.
