MAJOR－EFFICIENT SOLUTIONS AND WEAKLY MAJOR－EFFICIENT SOLUTIONS OF MULTIOBJECTIVE PROGRAMMING

In this papert the theory of major efficiency for multiobjective programmingis established.The major-efficient solutions and weakly major-efficient solutions of multiobjective programming given here are Pareto efficient solutions of the same multiobjectiveprogramming problem, but the converse is not true. In a ceratin sense , these solutionsare in fact better than any other Pareto efficient solutions. Some basic theorems whichcharacterize major-efficient solutions and weakly major-efficient solutions of multiobjective programming are stated and proved. Furthermore,the existence and some geometricproperties of these solutions are studied.

CHARACTERIZATION OF EFFICIENT SOLUTIONS FOR MULTI-OBJECTIVE OPTIMIZATION PROBLEMS INVOLVING SEMI-STRONG AND GENERALIZED SEMI-STRONG E-CONVEXITY

The authors of this article are interested in characterization of efficient solutions for special classes of problems. These classes consider semi-strong E-convexity of involved functions. Sufficient and necessary conditions for a feasible solution to be an efficient or properly efficient solution are obtained.

ε-strongly Efficient Solutions for Vector Optimization with Set-valued Maps

In locally convex Hausdorff topological vector spaces,ε-strongly efficient solutions for vector optimization with set-valued maps are discussed.Firstly,ε-strongly efficient point of set is introduced.Secondly,under the nearly cone-subconvexlike set-valued maps,the theorem of scalarization for vector optimization is obtained.Finally,optimality conditions of ε-strongly efficient solutions for vector optimization with generalized inequality constraints and equality constraints are obtained.

EXISTENCE RESULTS FOR GLOBALLY EFFICIENT SOLUTIONS OF VECTOR EQUILIBRIUM PROBLEMS VIA A GENERALIZED KKM PRINCIPLE

The aim of this article is to present new existence results for globally efficient solutions of a strong vector equilibrium problem given by a sum of two functions via a generalized KKM principle, and to establish the connectedness of the solutions set.

Generating Efficient Solutions in Bilevel Multi-Objective Programming Problems

In this paper, we address bilevel multi-objective programming problems (BMPP) in which the decision maker at each level has multiple objective functions conflicting with each other. Given a BMPP, we show how to construct two artificial multiobjective programming problems such that any point that is efficient for both the two problems is an efficient solution of the BMPP. Some necessary and sufficient conditions for which the obtained result is applicable are provided. A complete procedure of the implementation of an algorithm for generating efficient solutions for the linear case of BMPP is presented. A numerical example is provided to illustrate how the algorithm operates.

Efficient Authentication Scheme for UAV-Assisted Mobile Edge Computing

Preserving privacy is imperative in the new unmanned aerial vehicle(UAV)-assisted mobile edge computing(MEC)architecture to ensure that sensitive information is protected and kept secure throughout the communication.Simultaneously,efficiency must be considered while developing such a privacy-preserving scheme because the devices involved in these architectures are resource constrained.This study proposes a lightweight and efficient authentication scheme for theUAV-assistedMECenvironment.The proposed scheme is a hardware-based password-less authentication mechanism that is based on the fact that temporal and memory-related efficiency can be significantly improved while maintaining the data security by adopting a hardwarebased solution with a simple implementation.The proposed scheme works in four stages:system initialization,EU registration,EU authentication,and session establishment.It is implemented as a single hardware chip comprising registers and XOR gates,and it can run the entire process in one clock cycle.Consequently,the proposed scheme has significantly higher efficiency in terms of runtime and memory consumption compared to other prevalent methods in the area.Simulations are conducted to evaluate the proposed authentication algorithm.The results show that the scheme has an average execution time of 0.986 ms and consumes average memory of 34 KB.The hardware execution time is approximately 0.39 ns,which is a significantly less than the prevalent schemes,whose execution times range in milliseconds.Furthermore,the security of the proposed scheme is examined,and it is resistant to brute-force attacks.Around 1.158×10^(77) trials are required to overcome the system’s security,which is not feasible using fastest available processors.

Efficient Solution to Electromagnetic Scattering Problems of Bodies of Revolution by Compressive Sensing

Under the theory structure of compressive sensing （CS）, an underdetermined equation is deduced for describing the discrete solution of the electromagnetic integral equation of body of revolution （BOR）, which will result in a small-scale impedance matrix. In the new linear equation system, the small-scale impedance matrix can be regarded as the measurement matrix in CS, while the excited vector is the measurement of unknown currents. Instead of solving dense full rank matrix equations by the iterative method, with suitable sparse representation, for unknown currents on the surface of BOR, the entire current can be accurately obtained by reconstructed algorithms in CS for small-scale undetermined equations. Numerical results show that the proposed method can greatly improve the computgtional efficiency and can decrease memory consumed.

Reasons and Solutions of the Time-consuming College English Teaching with Low Efficiency

College English teaching has been regarded as time- consuming with low efficiency for a long time. This thesis proceeds with the entity of English education in China, deals with the main problems lying in the current college English teaching from 3 perspectives, including the nation and society, teachers, and students, and provides 5 suggestions accordingly.

Power transfer efficiency in an air-breathing radio frequency ion thruster

Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit missions due to its high specific impulse and efficiency. In this paper, the power transfer efficiency of the radio frequency ion thruster with different gas compositions is studied experimentally, which is obtained by measuring the radio frequency power and current of the antenna coil with and without discharge operation. The results show that increasing the turns of antenna coils can effectively improve the radio frequency power transfer efficiency, which is due to the improvement of Q factor. In pure N_2 discharge,with the increase of radio frequency power, the radio frequency power transfer efficiency first rises rapidly and then exhibits a less steep increasing trend. The radio frequency power transfer efficiency increases with the increase of gas pressure at relatively high power, while declines rapidly at relatively low power. In N_(2)/O_(2) discharge, increasing the N_(2) content at high power can improve the radio frequency power transfer efficiency, but the opposite was observed at low power. In order to give a better understanding of these trends, an analytic solution in limit cases is utilized, and a Langmuir probe was employed to measure the electron density. It is found that the evolution of radio frequency power transfer efficiency can be well explained by the variation of plasma resistance, which is related to the electron density and the effective electron collision frequency.

An Efficient Accurate Direct Solution of Poisson's Equation for Computation of Meteorological Parameters

Poisson's equation is solved numerically by two direct methods, viz. Block Cyclic Reduction (BCR) method and Fourier Method. Qualitative and quantitative comparison between the numerical solutions obtained by two methods indicates that BCR method is superior to Fourier method in terms of speed and accuracy. Therefore. BCR method is applied to solve (?)2(?)= ζ and (?)2X= D from observed vorticity and divergent values. Thereafter the rotational and divergent components of the horizontal monsoon wind in the lower troposphere are reconstructed and are com pared with the results obtained by Successive Over-Relaxation (SOR) method as this indirect method is generally in more use for obtaining the streamfunction ((?)) and velocity potential (X) fields in NWP models. It is found that the results of BCR method are more reliable than SOR method.

Crystallization behaviors of bayerite from sodium chromate alkali solutions

In order to clean production of chromium compounds, it is a critical process to remove aluminates and utilize aluminum compounds from artificial chromate alkali solutions. The effects of Na2 Cr O4 on the neutralization curve, Al（OH）3 precipitation efficiency and induction period of bayerite were investigated. The results indicate that the neutralization curve of the artificial chromate alkali solutions shows three distinct regions and its induction period is longer than that of pure sodium aluminate solutions at the same aluminum concentration. And the decreased temperature and volume fraction of CO2 enhance the particle size of bayerite β-Al（OH）3. Bayerite composed of agglomerates of rods and cone frustums was obtained from alkali metal chromate solutions with 28.5% CO2（volume fraction） at temperatures ranging from 50 °C to 70 °C. Coarse bayerite with particle size（d50） from 24.2 μm to 29.3 μm extremely has few impurities, which is suitable for comprehensive utilization.

Effect of polymer solution structure on displacement efficiency

In this paper, a series of experiments, including atomic force microscope （AFM）, environmental scanning electron microscope （ESEM）, and core displacement tests were conducted to investigate the effect of polymer solution structure on solution properties and oil displacement efficiency. The results show that in the HPAM solution polymer coils were formed and then aggregated into a loose structure, while the HAP2010 solution formed a strong network structure, which would significantly improve the solution viscosity and flow resistance so as to upgrade the capacity of piston-like oil displacement in highly permeable porous media. Meanwhile, the retention of the HAP2010 solution at pore throats were also enhanced, which could reduce water production during subsequent water flooding and enlarge the swept volume during polymer flooding. Therefore, enhancing the interaction among polymer molecules is an effective way to improve the displacement efficiency of polymer solutions in heavy oil reservoirs with high permeability.

优化船舶操纵性能计算分析

针对优化船舶操纵收敛效果不佳问题,引入多目标进化计算法优化船舶性能设计。基于多目标船舶操纵进化计算法,构建以船舶旋回直径和直线航行能力为评估指标的优化模型,采用基本不可行解差分算子,建立多目标优化计算法架构;选取优化基本不可行解,制定新的选择标准。与MOEA/D算法、加权算法和pareto算法比较分析结果表明,本研究算法可为船舶研究和设计人员提供更多优化船舶操纵设计策略的结果,从根本上提升了设计策略的收敛效能。

海外油气效益产量“二步决策法”研究及应用

海外油气项目具有投入大、风险大、回收期长等特点,开展效益产量决策方法研究对提升石油公司整体经营实力、提高抗风险能力举足轻重.本文旨在建立一套系统全面的效益产量经营决策方法,通过抓准项目效益影响因素,构建基于全局满意解集的效益产量“二步决策法”,实现一套“可全面可聚焦”的系统决策优选技术模型,最终以优选出的组合作为效益产量推荐方案,助推海外油气资产保值增值.本文创建的海外油气效益产量“二步决策法”,在国内某石油公司海外业务板块近4年的油气资产生产经营中取得了较好的应用效果,为该石油公司海外油气资产提效增效和高质量发展提供了可靠的技术支持.该方法也同样适用于国内上游油气开发板块效益产量优化决策,值得借鉴及推广.

二层多目标随机规划逼近弱有效解集的上半收敛性

为研究二层多目标随机规划逼近问题的弱有效解与精确的弱有效解之间的逼近收敛性,针对上、下层都带有约束条件的一类多目标二层随机规划的逼近问题,构建了二层多目标随机规划逼近问题的弱有效解集的上半收敛性理论框架。即在假设下层反馈到上层的最优解集函数为凸函数的前提下,借助严格凸函数的性质,利用多目标随机规划的弱有效解可以表示成相应的单目标随机规划最优解集交集的结构特征,建立了二层多目标随机规划逼近弱有效解集的上半收敛性,提供了逼近方法求解二层多目标随机规划弱有效解集可以近似替代精确的弱有效解集的理论依据。

干燥物系解析理论研究进展

干燥是含湿物料与有限介质两个独立物系,在限定的工艺条件下,自发进行能量传递和转换的过程。它隶属热力学范畴,而又不同于一般的热力过程,在物系边界存在诸多错综复杂的随机因素交互作用,使得基于热力学熵参数无法对实际过程的能效进行实时的定量评价。基于传递定律建立扩散模型,得不到传递系数严格意义的数学解,存在微积分结果偏离实际较远的情况;基于反应工程原理建立干燥动力学模型,存在指前因子,活化能,机理函数等待定的物理量,实际应用存在很大的局限性。如何从理论上完整地解析出实际过程,得到其分析解是热力学应用技术基础科学研究领域自古以来的重大理论难题。近十几年,笔者从非均相系热力学基础和干燥㶲分析入手,以干燥㶲传递和转换时的自由能消耗为统一尺度,以水分活度为一切干燥物系的共同属性,揭示了干燥物系固有特征函数及其理论解,丰富了热力学应用技术基础理论。该文从干燥物系解析理论发展的历史现状,阐释揭示物料干燥理论过程、评价工艺装备能效的解析理论与方法并指明其应用与发展的技术途径,为揭示物系传递机理、评价工艺装备系统能效、实现干燥过程自适应控制和制订科学的工艺能效评价标准提供参考。

计及[火用]效率的电-气-热综合能源系统多目标优化调度方法

为解决综合能源系统(integrated energy systems,IES)难以量质协同运行,且求解时间较长的问题,该文提出了一种计及[火用]效率的电-气-热综合能源系统多目标优化调度方法。首先,该文构建了IES模型,结合热力学第一、二定律,推导了该IES不同能源网络的源侧和负荷侧的[火用]方程以及[火用]效率等表达式;其次,为降低求解时间,提出了一个基于线性权重法的多目标函数求解与决策方法;最后,通过算例分析,验证了所提模型与方法的有效性。分析结果表明,相比于传统IES的优化问题,模型中考虑[火用]效率的多目标函数保证了能源品质的传输,促进了IES的量质协同运行,且该文所提求解方法的求解时间相比于遍历权重法降低了90.22%。

基于微注射的聚乳酸微针递送中药液效率评估

聚合物微针作为一种高效、安全、成型简单、节能环保的新型经皮药物递送医疗产品,逐渐得到关注。为研究聚合物微针体外递送中药液的效率,在已知的工艺条件下,通过微注射制备了聚乳酸(PLA)微针,利用扫描电镜观察其形貌特征,并对小鼠腹部皮肤进行穿刺,然后进行石蜡切片,观察其产生的微小通道,同时,通过体外透皮扩散评估了PLA微针预处理后的中药液递送效率。结果表明,针高为520μm的PLA微针具有较好的力学性能,能刺穿鼠皮皮肤的角质层,在微针预处理和未预处理Franz扩散实验中,120 min后,骨痹通方中药液预处理的吸光值为1.086881,未处理的吸光值为0.09004,经过线性拟合后,微针预处理实验组药物浓度至少是未处理对照组的10倍。

废旧磷酸铁锂电池集流体分离与正极材料再生

通过优化NaOH碱溶条件高效去除集流体黏结剂,保留完整铝箔;利用固相法再生LiFePO 4。当NaOH为0.8 mol/L、固液比20 mL/g、40℃反应10 min,正极材料的分离率达到99.78%,超声1 min后铝箔回收率为76%,解决了碱溶条件下铝箔回收的繁琐问题。球磨转速500 r、球磨5 h,补充10%高纯LiFePO 4的方式固相再生,再生LiFePO 4的最高放电比容量为新材料的94.75%,60次循环测试后为初始放电比容量的88.62%。

基于AHP与TOPSIS的水电站能效管理水平评价方法研究

针对现有水电站能效管理水平评价方法的不足,将层次分析法(AHP)和优劣解距离法(TOPSIS)引入评价过程中,综合考虑经济、安全和管理3个方面的因素,构建了水电站能效管理评价指标体系;针对九分位标度法的不足,采用指数标度法确定各指标权重;分别利用TOPSIS方法和专家打分法对定量指标、定性指标进行评分,并进一步实现水电站能效管理水平的综合评价;以某实际水电站为例,分析和计算2018-2022年的水电站能效管理水平得分,结果表明该电站能效管理水平总体上呈上升趋势。