基于风险计量指标的证券组合投资的数学模型及其应用

本文建立的证券组合投资的数学模型采用风险系数β作为控制证券投资风险的参数,其经济意义明确,实用性强。该模型应用于证券组合投资,效果明显,操作方便。     

Ecological Risk – Benefit Analysis of a Wetland Development Based on Risk Assessment Using Expected Loss of Biodiversity

Ecological risk from the development of a wetland is assessed quantitatively by means of a new risk measure, expected loss of biodiversity (ELB). ELB is defined as the weighted sum of the increments in the probabilities of extinction of the species living in the wetland due to its loss. The weighting for a particular species is calculated according to the length of the branch on the phylogenetic tree that will be lost if the species becomes extinct. The length of the branch on the phylogenetic tree is regarded as reflecting the extent of contribution of the species to the taxonomic diversity of the world of living things. The increments in the probabilities of extinction are calculated by a simulation used for making the Red List for vascular plants in Japan. The resulting ELB for the loss of Nakaikemi wetland is 9,200 years. This result is combined with the economic costs for conservation of the wetland to produce a value for the indicator of the cost per unit of biodiversity saved. Depending on the scenario, the value is 13,000 yen per year-ELB or 110,000 to 420,000 yen per year-ELB (1 US dollar = 110 yen in 1999).     

Risk‐Cost‐Benefit Analysis for Transportation Corridors with Interval Uncertainties of Heterogeneous Data

Access management, which systematically limits opportunities for egress and ingress of vehicles to highway lanes, is critical to protect trillions of dollars of current investment in transportation. This article addresses allocating resources for access management with incomplete and partially relevant data on crash rates, travel speeds, and other factors. While access management can be effective to avoid crashes, reduce travel times, and increase route capacities, the literature suggests a need for performance metrics to guide investments in resource allocation across large corridor networks and several time horizons. In this article, we describe a quantitative decision model to support an access management program via risk‐cost‐benefit analysis under data uncertainties from diverse sources of data and expertise. The approach quantifies potential benefits, including safety improvement and travel time savings, and costs of access management through functional relationships of input parameters including crash rates, corridor access point densities, and traffic volumes. Parameter uncertainties, which vary across locales and experts, are addressed via numerical interval analyses. This approach is demonstrated at several geographic scales across 7,000 kilometers of highways in a geographic region and several subregions. The demonstration prioritizes route segments that would benefit from risk management, including (i) additional data or elicitation, (ii) right‐of‐way purchases, (iii) restriction or closing of access points, (iv) new alignments, (v) developer proffers, and (vi) etc. The approach ought to be of wide interest to analysts, planners, policymakers, and stakeholders who rely on heterogeneous data and expertise for risk management.     

Reducing the Risk of Injury from Table Saw Use: The Potential Benefits and Costs of Automatic Protection

The use of table saws in the United States is associated with approximately 28,000 emergency department (ED) visits and 2,000 cases of finger amputation per year. This article provides a quantitative estimate of the economic benefits of automatic protection systems that could be designed into new table saw products. Benefits are defined as reduced health‐care costs, enhanced production at work, and diminished pain and suffering. The present value of the benefits of automatic protection over the life of the table saw are interpreted as the switch‐point cost value, the maximum investment in automatic protection that can be justified by benefit‐cost comparison. Using two alternative methods for monetizing pain and suffering, the study finds switch‐point cost values of $753 and $561 per saw. These point estimates are sensitive to the values of inputs, especially the average cost of injury. The various switch‐point cost values are substantially higher than rough estimates of the incremental cost of automatic protection systems. Uncertainties and future research needs are discussed.     

Benefits of Hybrid Lateral Transshipments in Multi‐Item Inventory Systems under Periodic Replenishment

Lateral transshipments are a method of responding to shortages of stock in a network of inventory‐holding locations. Conventional reactive approaches only seek to meet immediate shortages. The study proposes hybrid transshipments which exploit economies of scale by moving additional stock between locations to prevent future shortages in addition to meeting immediate ones. The setting considered is motivated by retailers who operate networks of outlets supplying car parts via a system of periodic replenishment. It is novel in allowing non‐stationary stochastic demand and general patterns of dependence between multiple item types. The generality of our work makes it widely applicable. We develop an easy‐to‐compute quasi‐myopic heuristic for determining how hybrid transshipments should be made. We obtain simple characterizations of the heuristic and demonstrate its strong cost performance in both small and large networks in an extensive numerical study.     

Inventory‐Based Dynamic Pricing with Costly Price Adjustment

We study an average‐cost stochastic inventory control problem in which the firm can replenish inventory and adjust the price at anytime. We establish the optimality to change the price from low to high in each replenishment cycle as inventory is depleted. With costly price adjustment, scale economies of inventory replenishment are reflected in the cycle time instead of lot size—An increased fixed ordering cost leads to an extended replenishment cycle but does not necessarily increase the order quantity. A reduced marginal cost of ordering calls for an increased order quantity, as well as speeding up product selling within a cycle. We derive useful properties of the profit function that allows for reducing computational complexity of the problem. For systems requiring short replenishment cycles, the optimal solution can be easily computed by applying these properties. For systems requiring long replenishment cycles, we further consider a relaxed problem that is computational tractable. Under this relaxation, the sum of fixed ordering cost and price adjustment cost is equal to (greater than, less than) the total inventory holding cost within a replenishment cycle when the inventory holding cost is linear (convex, concave) in the stock level. Moreover, under the optimal solution, the time‐average profit is the same across all price segments when the inventory holding cost is accounted properly. Through a numerical study, we demonstrate that inventory‐based dynamic pricing can lead to significant profit improvement compared with static pricing and limited price adjustment can yield a benefit that is close to unlimited price adjustment. To be able to enjoy the benefit of dynamic pricing, however, it is important to appropriately choose inventory levels at which the price is revised.     

服务人员互动风格对顾客忠诚的影响研究:关系利益的中介作用

在竞争性环境中,服务人员的有效互动尤其重要.基于此,应用关系营销理论,构建服务人员不同互动风格对顾客忠诚的影响模型,探索不同关系利益在其中的中介作用.以北京某品牌汽车4S店为背景展开调查,运用结构方程模型进行实证研究.研究结果表明,服务人员互动导向型风格既对顾客忠诚产生直接的影响,还通过顾客感知的信任利益和社会利益对其产生间接影响;任务导向型和自我导向型互动风格仅通过顾客感知的信任利益对顾客忠诚产生间接影响.     

合作研发中知识产权风险对合作行为影响的研究

知识产权风险已成为合作研发企业所面临的三大风险之首,因此,本文采用结构方程模型(SEM)结合243家企业的有效调研数据,实证分析了知识产权风险对企业合作行为的影响作用,并有助于企业在合作中针对所面临知识产权风险类型的不同来采用不同的措施进行动态防范。     

基于计划行为理论的信用卡使用意向分析及其营销策略研究

在计划行为理论的基础上,使用结构方程模型等数理统计方法,探析了消费者信用卡使用意向的影响因素,建构了消费者信用卡使用意向模型。研究表明,计划行为理论中信用卡态度和知觉行为控制变量对消费者信用卡使用意向有重要影响。此外,研究还进一步将消费者信用卡态度区分为便利性态度、金钱与信用态度,实证研究显示便利性态度对信用卡使用意向有重要影响,并且这种区分是合理的和必要的。     

大股东自利动机下的资本投资与配置效率研究

本文将终极控制人和直接控制人两类大股东的利益动机纳入统一的分析框架,实证考察了大股东自利动机下的资本投资选择与配置效率。研究发现:(1)终极控制人的现金流权比例越低,越有动机增加资本在固定资产、无形资产和长期股权上的自利性投入,导致总体投资规模扩张;(2)地方企业集团投资扩张受终极控制人自利动机的影响最强,央企投资所受影响最弱,民营企业居中;(3)随着控制层级的增加,终极控制人决策权的履行成本增大,企业资本配置行为因直接控制人持股比例高低而表现出"利益攫取"与"利益协同"两种效应;(4)在较高持股比例的收益分配激励下,直接控制人将减少自利性资本投入,抑制过度投资,提高资本配置效率。