求解多目标最优化问题的功效系数法

本文在E.C.Harrington功效系数法的基础上,提出一种改进的求解多目标最优化问题的功效系数法。文中运用“最小算子”构造总功效系数,使得线性多目标问题在求解中仍不失其线性,并转挟成一个单目标的线性规划问题。文中还给出了解的有效性证明和算例。     

Generating Correlation Matrices With Specified Eigenvalues Using the Method of Alternating Projections

ABSTRACT

This article describes a new algorithm for generating correlation matrices with specified eigenvalues. The algorithm uses the method of alternating projections (MAP) that was first described by Neumann. The MAP algorithm for generating correlation matrices is both easy to understand and to program in higher-level computer languages, making this method accessible to applied researchers with no formal training in advanced mathematics. Simulations indicate that the new algorithm has excellent convergence properties. Correlation matrices with specified eigenvalues can be profitably used in Monte Carlo research in statistics, psychometrics, computer science, and related disciplines. To encourage such use, R code (R Core Team) for implementing the algorithm is provided in the supplementary material.     

Health economic modeling to support surgery management at a Swedish hospital

Elective surgery management typically deals with a queue of patients that have to be scheduled for surgery within a certain time frame, considering both medical and economic constraints. In order to prevent the patient queue and waiting times from growing, surgery management has to decide whether to temporarily increase patient throughput at the regional hospital or have some patients scheduled for surgery at another hospital. In Sweden, a newly passed law states that patients who decide to receive surgery should not have to wait more than 90 days before this surgery is carried out. Therefore, if a patient decides to apply the new law by requesting surgery within 90 days, the regional hospital is obliged to arrange and pay for either in-house surgery or surgery at another hospital. In this paper, we suggest an approach using simulation including optimization for modeling surgery management decisions. We study a case based on data from a General Surgery Department at a Swedish hospital and present our results as a health economic evaluation. The results indicate an increase in the mean waiting times for medium prioritized patients when the new law is applied.     

SEO算法在网站建设和优化方面的应用研究

通过对搜索引擎和SEO（Search Engine Optimization）算法的研究，分析搜索引擎的工作原理和SEO的具体实施过程。再用一实例阐述SEO算法在网站建设和优化方面的作用，即在不损害用户体验的情况下，提高搜索引擎排名，从而提高网站的访问量和营销效果，最终提升网站的传播能力和盈利能力。     

大弹涂鱼肝脏蛋白质双向电泳技术的建立及优化

通过对不同裂解液配方、等电聚焦程序和SDS-PAGE方式等的对比实验,建立和优化了大弹涂鱼肝脏蛋白质组双向电泳的相关技术体系。结果显示采用裂解液中添加Tris和TBP,聚焦时适当延长除盐时间,提高聚焦电压和功率(伏-小时),能显著提高双向电泳图谱的分辨率,MSOG程序进行双向电泳(Multi-strips on One Gel MSOG),提高了双向凝胶的匹配率及有效性,降低了人为修饰点的增加,匹配率高达90%。通过相关条件优化提高了大弹涂鱼肝脏蛋白双向电泳图谱的分辨率,为后续大弹涂鱼的毒理蛋白质组学研究提供技术保障。     

高负债与资本结构不合理的关系探析--兼论我国国有企业资本结构优化

资本结构是指权益资本与负债资本的比例关系,资本结构的核心问题就是负债问题.资本结构是一个动态的概念,考察资本结构合不合理不能仅从负债高低考虑,而应权衡各方面的因素综合分析.     

Making combination vaccines more accessible to low-income countries: The antigen bundle pricing problem

Combination vaccines have become the preferred choice for immunizing children in high- and middle-income countries. However, these new vaccines are prohibitively expensive for low-income countries, causing them to rely on older, less-expensive vaccines. This product divergence decreases economies of scale for the purchase of vaccines and eliminates the financial incentive for manufacturers to maintain production of less-expensive vaccines or even to develop new vaccines for diseases affecting developing countries. This paper treats combination vaccines as bundles of antigens that can be priced as a single item. Such bundles are used to formulate an optimization problem that determines the combination vaccine allocation between vaccine producers and different countries under a price discrimination agreement. The objective of the optimization problem is to satisfy countries' antigen demand at the lowest possible price, while providing a reasonable profit for the vaccine producers. The optimization problem results in a mixed-integer non-linear programming model that maximizes the sum of manufacturing profits and the customer surplus, and hence, it maximizes the total social surplus. Moreover, a constructive heuristic is proposed to determine an approximation to the best allocation of combination vaccines and their range of feasible prices. Computational results show that vaccine prices in all market segments become more affordable as the supply of the most complex combination vaccines becomes more available to low-income countries.     

Improved governance of Indian school system through school consolidation

Formal education is provided in schools that should be accessible to citizens, facilitating them to reach the schools with ease, safety and without travelling too large a distance. The requirement of accessibility, however, brings into consideration the corresponding cost and resource utilization. There exists a vast school network in India, with many schools established under the Sarva Shiksha Abhiyan program. However, the existence of too many schools, mostly low in enrolment, is creating problems in terms of quality of teaching and infrastructural facilities offered by these schools. This trade-off between large size schools having good infrastructure and conducive ecosystem, and many small schools deprived of it, can be addressed by appropriate school consolidation. The current study presents a mathematical programming model for school consolidation that aims to minimize the total disruption and transfer the students to an alternative school considering the school network. The model is then applied to a case for a district in the Indian state of Karnataka. Various scenario runs have been done to come out with the appropriate policy parameters for the given district and the results are highly encouraging. The model and analysis can be replicated as well as customized according to the needs of different states.     

借助拉格朗日乘数法优化社会扩大再生产

文章提出一种借助拉格朗日乘数法优化两大部类社会扩大再生产的方法。运用拉格朗日函数法,将获得扩大再生产的最优解析解问题,转化成目标函数在定义域边界点上的若干取值比较和判定问题,使问题变得很简单、明确。进而容易地确定扩大再生产的最优解所处的边界点,获得最优解。借助马克思《资本论》中的一个举例,对此方法做了计算验证。     

两阶段法求解混装模式下的加热炉调度

针对目前加热炉调度模型少有考虑混装模式下加热炉调度优化的不足,建立了连铸-热轧混装-体化模式下的加热炉生产调度优化模型,并提出了基于贪婪算法和模拟退火算法的两阶段求解方法.生产数据测试表明该模型和算法能有效解决加热炉调度问题.