A Discrete Multi-Objective Squirrel Search Algorithm for Energy-Efficient Distributed Heterogeneous Permutation Flowshop with Variable Processing Speed

In the manufacturing industry,reasonable scheduling can greatly improve production efficiency,while excessive resource consumption highlights the growing significance of energy conservation in production.This paper studies the problem of energy-efficient distributed heterogeneous permutation flowshop problem with variable processing speed(DHPFSP-VPS),considering both the minimum makespan and total energy consumption(TEC)as objectives.A discrete multi-objective squirrel search algorithm(DMSSA)is proposed to solve the DHPFSPVPS.DMSSA makes four improvements based on the squirrel search algorithm.Firstly,in terms of the population initialization strategy,four hybrid initialization methods targeting different objectives are proposed to enhance the quality of initial solutions.Secondly,enhancements are made to the population hierarchy system and position updating methods of the squirrel search algorithm,making it more suitable for discrete scheduling problems.Additionally,regarding the search strategy,six local searches are designed based on problem characteristics to enhance search capability.Moreover,a dynamic predator strategy based on Q-learning is devised to effectively balance DMSSA’s capability for global exploration and local exploitation.Finally,two speed control energy-efficient strategies are designed to reduce TEC.Extensive comparative experiments are conducted in this paper to validate the effectiveness of the proposed strategies.The results of comparing DMSSA with other algorithms demonstrate its superior performance and its potential for efficient solving of the DHPFSP-VPS problem.

Mechanism of heterogeneous distribution of Cr-containing dispersoids in DC casting 7475 aluminum alloy

The actual effective partition coefficients of Mg and Cr in a cross-section of a dendrite arm in a direct-chill(DC)-casting ingot of 7475 aluminum alloy are obtained.Meanwhile,by analyzing the microstructure,the mechanism of the heterogeneous distribution of E(Al_(18)Mg_(3)Cr_(2))dispersoids in this DC ingot is revealed.The results show that the actual effective partition coefficients of Mg and Cr are 0.650 and 1.392,respectively,and they describe the heterogeneous distributions of Mg and Cr along the direction of radius of the cross-section of the dendrite arm of the alloy.After homogenization treatment at 470℃ for 24 h,Mg diffuses uniformly,but Cr hardly diffuses.Both the concentrations of Mg and Cr and the sites of heterogeneous nucleation in the alloy are the determinants of the formation of E dispersoids simultaneously.The heat treatment at 250℃ for 72 h provides a large number of the sites of heterogeneous nucleation of the formation of fine E dispersoids that will be formed in the center of the cross-section during the subsequent heat treatment at higher temperature.

EEMD and bidimensional RLS to suppress physiological interference for heterogeneous distribution in fNIRS study

Near-infrared spectroscopy(NIRS)can provide the hemodynamics information based on the hemoglobin concentration representing the blood oxygen metabolism of the cerebral cortical,which can be deployed for the cerebral function study.However,NIRS-based cerebral function detection accuracy can be signi¯cantly in°uenced by the physiological activities such as cardic cycle,respiration,spontaneous low-frequency oscillation and ultra-low frequency oscillation.The distribution difference of the capillary,artery and vein leads to the heterogeneity feature of the cerebral tissues.In the case that the heterogeneity is not serious,good detection accuracy and stable performance can be achieved through the regression analysis as the reference signal can well represent the interference in the measurement signal when conducting the multi-distance measurement approach.The direct use of the reference signal to estimate the interference is not able to achieve good performance in the case that the heterogeneity is serious.In this study,the cerebral function activity signal is extracted using recursive least square(RLS)method based on the multi-distance measurement method in which the reference signal is processed by ensemble empirical mode decomposition(EEMD)algorithm.The temporal and dimensional correlation of the neighboring sampling values are applied to estimate the interference in the measurement signal.Monte Carlo simulation based on a heterogeneous model is adopted here to investigate the effectiveness of this methodology.The results show that this methodology can effectively suppress the physiological interference and improve the detection accuracy of cerebral activity signal.

Competitive and Cooperative-Based Strength Pareto Evolutionary Algorithm for Green Distributed Heterogeneous Flow Shop Scheduling

This work aims to resolve the distributed heterogeneous permutation flow shop scheduling problem(DHPFSP)with minimizing makespan and total energy consumption(TEC).To solve this NP-hard problem,this work proposed a competitive and cooperative-based strength Pareto evolutionary algorithm(CCSPEA)which contains the following features:1)An initialization based on three heuristic rules is developed to generate a population with great diversity and convergence.2)A comprehensive metric combining convergence and diversity metrics is used to better represent the heuristic information of a solution.3)A competitive selection is designed which divides the population into a winner and a loser swarms based on the comprehensive metric.4)A cooperative evolutionary schema is proposed for winner and loser swarms to accelerate the convergence of global search.5)Five local search strategies based on problem knowledge are designed to improve convergence.6)Aproblem-based energy-saving strategy is presented to reduce TEC.Finally,to evaluate the performance of CCSPEA,it is compared to four state-of-art and run on 22 instances based on the Taillard benchmark.The numerical experiment results demonstrate that 1)the proposed comprehensive metric can efficiently represent the heuristic information of each solution to help the later step divide the population.2)The global search based on the competitive and cooperative schema can accelerate loser solutions convergence and further improve the winner’s exploration.3)The problembased initialization,local search,and energy-saving strategies can efficiently reduce the makespan and TEC.4)The proposed CCSPEA is superior to the state-of-art for solving DHPFSP.

Land Surface Hydrology Parameterization over Heterogeneous Surface for the Study of Regional Mean Runoff Ratio with Its Simulations

An analytical expression for subgrid–scale inhomogeneous runoff ratios generated by heterogeneous soil moisture content and climatic precipitation forcing is presented based on physical mechanisms for land surface hydrology and theory of statistical probability distribution. Thereby the commonly used mosaic parameterization of subgrid runoff ratio was integrated into a statistical–dynamic scheme with the bulk heterogeneity of a grid area included. Furthermore, a series of numerical experiments evaluating the reliability of the parameterization were conducted using the data generated by the emulated simulation method. All the experimental results demonstrate that the proposed scheme is feasible and practical.

Resilience approach for heterogeneous distributed networked unmanned weapon systems

Disconnection in the distributed heterogeneous networked unmanned weapon systems is caused by multiple weapon units＇ failure. The technical routes were analyzed to achieve resilience in the disconnection situation. A heterogeneous distributed network model of networked unmanned weapon systems was established. And an approach of adding relay weapon units was proposed to a- chieve fault tolerance after weapon units＇ failure due to attack or energy exhaustion. An improved ge- netic algorithm was proposed to determine and optimize the position of the relay weapon units. Simulation results in the MATLAB show that the improved resilience-based genetic algorithm can restore the network connection maximally when the number of relay units is limited, the network can keep on working after failure, and the implementation cost is controlled in a reasonable range.

Dynamic reconfiguration for TEG systems under heterogeneous temperature distribution via adaptive coordinated seeker

A thermoelectric generation(TEG)system has the weakness of relatively low thermoelectric conversion efficiency caused by heterogeneous temperature distribution(HgTD).Dynamic reconfiguration is an effective technique to improve its overall energy efficiency under HgTD.Nevertheless,numerous combinations of electrical switches make dynamic reconfiguration a complex combinatorial optimization problem.This paper aims to design a novel adaptive coordinated seeker(ACS)based on an optimal configuration strategy for large-scale TEG systems with series-paral-lel connected modules under HgTDs.To properly balance global exploration and local exploitation,ACS is based on'divide-and-conquer'parallel computing,which synthetically coordinates the local searching capability of tabu search(TS)and the global searching capability of a pelican optimization algorithm(POA)during iterations.In addition,an equivalent re-optimization strategy for a reconfiguration solution obtained by meta-heuristic algorithms(MhAs)is proposed to reduce redundant switching actions caused by the randomness of MhAs.Two case studies are carried out to assess the feasibility and superiority of AcS in comparison with the artificial bee colony algorithm,ant colony optimization,genetic algorithm,particle swarm optimization,simulated annealing algorithm,TS,and POA.Simulation results indicate that ACS can realize fast and stable dynamic reconfiguration of a TEG system under HgTDs.In addition,RTLAB platform-based hardware-in-the-loop experiments are carried out to further validate the hardware implemen-tation feasibility.

Application of 2D fluorescence correlation method to investigate the dilution-induced heterogeneous distribution of the bound FMN in azoreductase

AzoR is a homodimeric,flavin mononucleotide（FMN）-containing,NADH-dependent azoreductase from Escherichia coli.In this paper,we investigated the effect of the concentration of both AzoR and R59 G on the spectral behavior of the bound FMN using two-dimensional fluorescence correlation spectra.Two cross peaks（530,490） and（580,530） were observed from the dilution-induced 2D asynchronous correlation map of wt AzoR,while only one cross peak appeared at（600,530） for R59 C mutant.This result indicated that the mutation at site 59 influenced the formation of dilution-induced intermediates.The specific activity of both AzoR and R59 G mutant was unaffected by dilution when the enzyme concentration is below 1 μmol/L,which suggested that no significant dissociation of FMN occurred at low concentrations.Additionally,in order to explore the origin of these intermediates,we carried out a2 D correlation analysis using excitation wavelength-dependent fluorescence emission spectroscopy.The results showed that there coexisted two types of FMN that emitted fluorescence at 530 nm and 500 nm,respectively.Taken together,these results suggested that the 2D method is a very powerful method to identify the heterogeneous distribution of the bound FMN in solution.

Formation and influencing factors of carbonate source rock of the Lower Permian Chihsia Formation in Chaohu region, Anhui Province

Highly-mature carbonate source rock is essential to the exploration of oil and gas in southern China. In this study, the carbonate strata in the relatively well-developed Lower Permian Chihsia Formation (located in Chaohu, Lower Yangtze) were targeted, and the formation and influencing factors of source rock were discussed based on paleoenvironment reconstruction using comprehensive sedimentology, palynofacies, and organic geochemistry data. The results demonstrate that the Chihsia Formation is oxygen-deficient biogenic carbonate sediments, with marked variations in the organic and inorganic components, formed during a period of Permian transgression. The formation of source rock is the combined result of high bioproductivity and oxygen-deficient environment generated by transgression and oxygenation events which frequently occurred during transgression periods. Source rock was affected by self-dilution effects and diagenesis, causing its heterogeneous distribution in many intervals. Source rock is over 40 m thick, and can be identified based on its different organic, biological, and mineral composition characteristics. The carbonate rock appears to require no specific clay content in order to become a source rock. The combination of sedimentology, palynofacies, and organic geochemistry has provided an effective means for evaluating and predicting high-maturity carbonate source rock in the region.

Origin of strong solid solution strengthening in the CrCoNi-W medium entropy alloy

Solid solution strengthening is one of the most conventional strategies for optimizing alloys strength,while the corresponding mechanisms can be more complicated than we traditionally thought specifically as heterogeneity of microstructure is involved.In this work,by comparing the change of chemical distribution,dislocation behaviors and mechanical properties after doping equivalent amount of tungsten(W)atoms in CrCoNi alloy and pure Ni,respectively,it is found that the alloying element W in CrCoNi alloy resulted in much stronger strengthening effect due to the significant increase of heterogeneity in chemical distribution after doping trace amount of W.The large atomic scale concentration fluctuation of all elements in CrCoNi-3W causes dislocation motion via strong nanoscale segment detrapping and severe dislocation pile up which is not the case in Ni-3W.The results revealed the high sensitivity of elements distribution in multi-principle element alloys to composition and the significant consequent influence in tuning the mechanical properties,giving insight for complex alloy design.

Effects of plant species richness on stand structure and productivity

Aims Aboveground biomass production commonly increases with species richness in plant biodiversity experiments.Little is known about the direct mechanisms that cause this result.We tested if by occupying different heights and depths above and below ground,and by optimizing the vertical distribution of leaf nitrogen,species in mixtures can contribute to increased resource uptake and,thus,increased productivity of the community in comparison with monocultures.Methods We grew 24 grassland plant species,grouped into four nonoverlapping species pools,in monoculture and 3-and 6-species mixture in spatially heterogeneous and uniform soil nutrient conditions.Layered harvests of above-and belowground biomass,as well as leaf nitrogen and light measurements,were taken to assess vertical canopy and root space structure.Important Findings The distribution of leaf mass was shifted toward greater heights and light absorption was correspondingly enhanced in mixtures.How ever,only some mixtures had leaf nitrogen concentration profiles predicted to optimize whole-community carbon gain,whereas in other mixtures species seemed to behave more‘selfish’.Nevertheless,even in these communities,biomass production increased with species richness.The distribution of root biomass below ground did not change from monocultures to three-and six-species mixtures and there was also no indication that mixtures were better than monocultures at extracting heterogeneously as compared to homogeneously distributed soil resources.We conclude that positive biodiversity effect on aboveground biomass production cannot easily be explained by a single or few common mechanisms of differential space use.Rather,it seems that mechanisms vary with the particular set of species combined in a community.

Task assignment for minimizing application completion time using honeybee mating optimization

Effective task assignment is essential for achieving high performance in heterogeneous distributed computing systems. This paper proposes a new technique for minimizing the parallel application time cost of task assignment based on the honeybee mating optimization （HBMO） algorithm. The HBMO approach combines the power of simulated annealing, genetic algorithms, and an effective local search heuristic to find the best possible solution to the problem within an acceptable amount of computation time. The performance of the proposed HBMO algorithm is shown by comparing it with three existing task assignment techniques on a large number of randomly generated problem instances. Experimental results indicate that the proposed HBMO algorithm outperforms the competing algorithms.

Proportional Current Sharing Based on Periodic Dynamic Event-driven H_(∞) Consensus in DC Microgrids with Power Coupling

Although the proportional current sharing has been widely studied,the heterogeneous characteristic of the different interfaced converters and power coupling terms among distributed generators(DGs)are rarely considered.Therefore,this paper proposes a secondary H_(∞)consensus method with a periodic dynamic event-driven scheme for dc microgrids with power coupling to accomplish the precise proportional current-sharing.It is useful for reducing carbon.First,a generalized converter is constructed through equivalent transformation between rectifier and boost converter.Moreover,the heterogeneous characteristic of the interfaced converters regarding different DGs,such as wind and solar generators,is embedded into controller design.Furthermore,the standard linear heterogeneous multi-agent system with power coupling term is built.On this basis,the problem of proportional current sharing is modified into the output consistency problem of multi-agent systems.Furthermore,the H_(∞)consensus approach is proposed to accomplish the precise proportional current sharing.Meanwhile,to shorten communication bandwidth,the periodic dynamic event-driven communication strategy is designed.Compared with traditional event-driven communication schemes,a lower communication frequency has been obtained through the proposed communication scheme.In addition,this communication scheme not only avoids Zeno-behavior,but also acquires the smallest sampling time interval.Finally,effectiveness of the proposed approach is verified by two test systems.

A Message-Based Distributed Kernel for a Full Heterogeneous Environment

This paper presents the design and implementation of a message-based distributed operating system kernel NDOS. The main purpose of the kernel is to support a distributed data processing system and a distributed DBMS. It uses the abstraction of communication between processes as basic mechanism. In NDOS, services and facilities such as message passing and process synchronization, which are related to IPC and may cause the change of the state of a process, are integrated into a single concept, an event. The initial version of NDOS ker- nel has been implemented on a full heterogeneous environment of different machines, LANs, and OSs with the original high-layered systems and applications are still provided.