Robust consumption‐investment problem under CRRA and CARA utilities with time‐varying confidence sets

We consider a robust consumption‐investment problem under constant relative risk aversion and constant absolute risk aversion utilities. The time‐varying confidence sets are specified by Θ, a correspondence from [0, T] to the space of the Lévy triplets, and describe a priori drift, volatility, and jump information. For each possible measure, the log‐price processes of stocks are semimartingales, and the triplet of their differential characteristics is almost surely a measurable selector from the correspondence Θ. By proposing and investigating the global kernel, an optimal policy and a worst‐case measure are generated from a saddle point of the global kernel, and they constitute a saddle point of the objective function.     

Informality and mobility

Informality is a defining characteristic of labour markets in developing and transition countries. This paper analyzes patterns of mobility across different forms of formal and informal employment in Russia. Using the Russian Longitudinal Monitoring Survey household panel we estimate a dynamic multinomial logit model with individual heterogeneity and correct for the initial conditions problem. Simulations show that structural state dependence is weak and that transition rates from informal to formal employment are not lower than from non-employment. These results lend support to the integrated view of the labour market.     

高职学生问题解决能力培养途径研究——以江苏经贸职业技术学院为例

培养大学生的问题解决能力,是提高大学生综合素养的重要手段.以江苏经贸职业技术学院为例,分析目前高职学生问题解决能力的现状、面临的主要问题及处理问题的方式,研究高职学生问题解决能力的培养模型及主要途径.     

Electrification of a city bus network—An optimization model for cost-effective placing of charging infrastructure and battery sizing of fast-charging electric bus systems

The deployment of battery-powered electric bus systems within the public transportation sector plays an important role in increasing energy efficiency and abating emissions. Rising attention is given to bus systems using fast charging technology. This concept requires a comprehensive infrastructure to equip bus routes with charging stations. The combination of charging infrastructure and bus batteries needs a reliable energy supply to maintain a stable bus operation even under demanding conditions. An efficient layout of the charging infrastructure and an appropriate dimensioning of battery capacity are crucial to minimize the total cost of ownership and to enable an energetically feasible bus operation. In this work, the central issue of jointly optimizing the charging infrastructure and battery capacity is described by a capacitated set covering problem. A mixed-integer linear optimization model is developed to determine the minimum number and location of required charging stations for a bus network as well as the adequate battery capacity for each bus line. The bus energy consumption for each route segment is determined based on individual route, bus type, traffic, and other information. Different scenarios are examined in order to assess the influence of charging power, climate, and changing operating conditions. The findings reveal significant differences in terms of required infrastructure. Moreover, the results highlight a trade-off between battery capacity and charging infrastructure under different operational and infrastructure conditions. This paper addresses upcoming challenges for transport authorities during the electrification process of the bus fleets and sharpens the focus on infrastructural issues related to the fast charging concept.     

浅谈招投标存在的问题以及相应对策

招投标的引入,为建筑工程市场营造了公平竞争的环境,为降低建筑招标单位投资成本和提高建筑整体质量起到了积极的作用。但目前我国建筑工程招投标存在很多问题,本文针对部分典型问题进行了探讨,并提出了相应的应对措施。     

推进我国企业内部审计发展的思考

本文深刻分析了当前我国企业内部审计发展中存在的主要问题,提出了推进我国内部审计发展的具体措施。     

建筑装饰工程施工管理中存在的问题及解决办法探讨

本文就建筑装饰工程管理中存在的问题提出了一些相应的解决措施。     

基于Metlab的多机器人围捕问题的研究

本文将追捕-逃跑问题按空间、时间离散化后转为一个对策模型,并利用Matlab软件,采用栅格建模的方法来模拟仿真环境,对四个追捕机器人追捕一个目标机器人的实例进行了仿真。通过仿真发现了该支付函数的缺陷。基于此原因,重新定义了局中人的支付函数,通过衰减因子μ,在追捕的不同阶段,根据追捕的具体情况灵活地调整距离影响系数和有效包围系数的权重,从而提高了追捕的效率。     

浅谈高速公路养护存在的问题及解决措施

本文论述了高速公路养护存在的主要问题,并提出一系列解决措施。     

Diversification strategy with random yield suppliers for a mean–variance risk-sensitive manufacturer

We consider the diversification strategy for a mean–variance risk-sensitive manufacturer with unreliable suppliers. We first analyze the linear model and find that the suppliers are selected according to the descending order of their contributed marginal expected profit, and increasing the manufacturer’s risk-averseness leads to a more even allocation of demand across the suppliers. Then, we study the general newsvendor model. By approximating the leftover inventory with a normal distribution, we establish the general properties of the active supplier set and show that the supplier selection rule is similar to that under the risk-neutral setting when the demand uncertainty is large. Moreover, we conjecture that the selection rule also applies when the demand uncertainty is low, which we verify with an extensive numerical study. Our paper makes two contributions: First, we establish the properties of the optimal diversification strategy and develop corresponding insights into the trade off between cost and reliability under the mean–variance framework. Second, we perform comparative statics on the optimal solution, with a particular emphasis on investigating how changes in the supplier’s cost or reliability affect the risk-averse manufacturer’s ordering decisions and customer service level.