Variable Reduction Strategy Integrated Variable Neighborhood Search and NSGA-II Hybrid Algorithm for Emergency Material Scheduling

Developing a reasonable and efficient emergency material scheduling plan is of great significance to decreasing casualties and property losses.Real-world emergency material scheduling(EMS)problems are typically large-scale and possess complex constraints.An evolutionary algorithm(EA)is one of the effective methods for solving EMS problems.However,the existing EAs still face great challenges when dealing with large-scale EMS problems or EMS problems with equality constraints.To handle the above challenges,we apply the idea of a variable reduction strategy(VRS)to an EMS problem,which can accelerate the optimization process of the used EAs and obtain better solutions by simplifying the corresponding EMS problems.Firstly,we define an emergency material allocation and route scheduling model,and a variable neighborhood search and NSGA-II hybrid algorithm(VNS-NSGAII)is designed to solve the model.Secondly,we utilize VRS to simplify the proposed EMS model to enable a lower dimension and fewer equality constraints.Furthermore,we integrate VRS with VNS-NSGAII to solve the reduced EMS model.To prove the effectiveness of VRS on VNS-NSAGII,we construct two test cases,where one case is based on a multi-depot vehicle routing problem and the other case is combined with the initial 5∙12 Wenchuan earthquake emergency material support situation.Experimental results show that VRS can improve the performance of the standard VNS-NSGAII,enabling better optimization efficiency and a higher-quality solution.

Bibliometric analysis and system review of vehicle routing optimization for emergency material distribution

Determining the optimal vehicle routing of emergency material distribution(VREMD)is one of the core issues of emergency management,which is strategically important to improve the effectiveness of emergency response and thus reduce the negative impact of large-scale emergency events.To summarize the latest research progress,we collected 511VREMD-related articles published from 2010 to the present from the Scopus database and conducted a bibliometric analysis using VOSviewer software.Subsequently,we cautiously selected 49 articles from these publications for system review;sorted out the latest research progress in model construction and solution algorithms;and summarized the evolution trend of keywords,research gaps,and future works.The results show that domestic scholars and research organizations held an unqualified advantage regarding the number of published papers.However,these organizations with the most publications performed poorly regarding the number of literature citations.China and the US have contributed the vast majority of the literature,and there are close collaborations between researchers from both countries.The optimization model of VREMD can be divided into single-,multi-,and joint-objective models.The shortest travel time is the most common optimization objective in the single-objective optimization model.Several scholars focus on multiobjective optimization models to consider conflicting objectives simultaneously.In recent literature,scholars have focused on the impact of uncertainty and special events(e.g.,COVID-19)on VREMD.Moreover,some scholars focus on joint optimization models to optimize vehicle routes and central locations(or material allocation)simultaneously.Solution algorithms can be divided into two primary categories,i.e.,mathematical planning methods and intelligent evolutionary algorithms.The branch and bound algorithm is the most dominant mathematical planning algorithm,while genetic algorithms and their enhancements are the most commonly used intelligent evolutionary algorithms.It is shown that the nondominated sorting genetic algorithmⅡ(NSGA-Ⅱ)can effectively solve the multiobjective model of VREMD.To further improve the algorithm’s performance,researchers have proposed improved hybrid intelligent algorithms that combine the advantages of NSGA-Ⅱand certain other algorithms.Scholars have also proposed a series of optimization algorithms for specific scenarios.With the development of new technologies and computation methods,it will be exciting to construct optimization models that consider uncertainty,heterogeneity,and temporality for large-scale real-world issues and develop generalized solution approaches rather than those applicable to specific scenarios.

Material Flow:An Emerging Business in China

AS a consequence of China’s past decades as a planned economy, with its over emphasis on production and neglect of circulation, the country’s material flow has long remained at an undeveloped level, with small-scale operation, poor organization, and a lack of equipment. For too long, production and circulation have been unrelated processes.

Is the hardness of material harder than diamond reliable?

With the development of new synthesis methods and chemistries,a number of new superhard materials have been reported to be harder than diamond.While such materials are highly desirable due to their wide-ranging applications,there are some inherent uncertainties in the methods utilized to determine and define the hardness of such materials.In this paper,we employed the standard Vickers diamond indenter and substitute indenters with the same shape to measure the hardness of nine ceramics and superhard materials within well-defined criteria and methodology,for the assessment of consistency in the hardness testing.The findings and the developed testing method in the current study have broad implications in characterizing new and emerging superhard materials,leading to new discoveries.

Structures,properties,and challenges of emerging 2D materials in bioelectronics and biosensors

Bioelectronics are powerful tools for monitoring and stimulating biological and biochemical processes,with applications ranging from neural interface simulation to biosensing.The increasing demand for bioelectronics has greatly promoted the development of new nanomaterials as detection platforms.Recently,owing to their ultrathin structures and excellent physicochemical properties,emerging two-dimensional(2D)materials have become one of the most researched areas in the fields of bioelectronics and biosensors.In this timely review,the physicochemical structures of the most representative emerging 2D materials and the design of their nanostructures for engineering highperformance bioelectronic and biosensing devices are presented.We focus on the structural optimization of emerging 2D material-based composites to achieve better regulation for enhancing the performance of bioelectronics.Subsequently,the recent developments of emerging 2D materials in bioelectronics,such as neural interface simulation,biomolecular/biomarker detection,and skin sensors are discussed thoroughly.Finally,we provide conclusive views on the current challenges and future perspectives on utilizing emerging 2D materials and their composites for bioelectronics and biosensors.This review will offer important guidance in designing and applying emerging 2D materials in bioelectronics,thus further promoting their prospects in a wide biomedical field.

InN-Based Ill-Nitrides; A New Emerging Material System for Application in Optical Communications

The fact that InN has a direct bandgap of 0.75eV enables InN-based nitrides devices to cover the wavelength range from UV region to 1.8μm, therefore, emerging as a new material system for optical communication applications.

The ‘Development Plan of National Strategic Emerging Industries Promotes Breakthrough Development of High-end Equipment and New Material Industry

The State Council recently printed and distributed the Notice on the‘Development Plan of National Strategic Emerging Industries for the'Thirteenth Five Year Plan'’(The Plan),which made overall deployment and arrangement for development target,key tasks,