看涨期权契约与看跌期权契约对比分析研究

在面临相同随机市场需求的情况下,本文对期权契约中的看涨期权与看跌期权契约进行了对比分析,以期为决策者在实际采购活动中选择不同类型的期权契约时提供决策依据。通过模型建立与求解分析,本文得出了销售商接受期权契约时,契约参数需要满足的条件及相应的订购策略;并进一步得出了两种期权契约下,供应链达到协调状态时的具体条件,分析了此时契约参数对供销双方利润的影响,继而给出了两种期权契约的适用范围以及供销双方的契约选择偏好。在此基础上,本文还给出了不同期权契约下,供销双方各自利润均不低于其自身保留利润时契约参数的取值范围,并证明了两种期权契约均可有效提高销售商的利润水平。最后,本文通过算例对上述结论进行了验证。     

Scheduler – A System for Staff Planning

In this paper we propose a unified formulation based on (min?,+) algebra to express the dynamics of pull control policies for serial single product manufacturing systems. For policies such as basestock, kanban, extended kanban and generalized kanban, the formulation has the same parametric form with different parameters for each policy. To calculate these parameters efficiently, (min?,+) algebra tools are used. This formulation allows us to identify under what parameter values two different policies have the same dynamics behavior. This has been applied to extended kanban and generalized kanban.     

随机化策略的公平比较

采用随机化技术对敏感问题实施抽样调查，至今已有很多可供选择的随机化策略; 其中大多数策略是通过选择恰当的设计参数来达到改进效率的. 然而两种方案即使具有相同的设计参数值，但对个体的保护度也可能不同. 所以早期一些文献效率比较没有基于相同的对个体保护度， 因此那些比较是不公平的. 该文补充了这方面的理论。 在相同的保护度下，精确比较了这些已有的策略；得到的结果表明： 必须重新评价这些早期的随机化策略.     

Learning from similarities and differences: a reflection on the potentials and constraints of cross-national studies in mathematics

Research in mathematics education that crosses national boundaries provides new insights into the development and improvement of the teaching and learning of mathematics. In particular, cross-national comparisons lead researchers to more explicit understanding of their own implicit theories about how teachers teach and how children learn mathematics in their local contexts as well as what is going on in school mathematics in other countries. Further, when researchers from multiple countries and regions study collaboratively aspects of teaching and learning of mathematics, the taken-for-granted familiar practices in the classroom can be questioned. Such cross-national comparisons provide opportunities for researchers and educators to probe typical dichotomies such as “high-performing” versus “low performing”, “teacher-centred versus student-centred”, or even “East versus West”, in searching for similarities and differences in educational policies and practices in different cultural contexts.     

Comparison among three pull control policies: kanban, base stock, and generalized kanban

This paper is concerned with maketostock pull control policies. A classical policy is the kanban policy. Another policy, very easy to implement, is the base stock policy. These two policies contain one design parameter per stage. A general control policy, known as the generalized kanban policy, can also be used to implement the pull mechanism. The generalized kanban policy includes, as special cases, the kanban and the base stock policies. This policy uses two parameters for each stage of the production system. The aim of this paper is to provide qualitative and quantitative comparisons of these three policies. The results of our study will help to choose the policy to implement in order to control a production system. We give practical rules. We also show that if there is no delay in filling orders, all three policies have similar costs. However, for the systems studied, we show that, if there is a delay in filling orders, generalized kanban systems and base stock systems yield close to optimal costs, which are lower than costs of kanban systems for the same service quality.     

LIFO Distribution Systems

The regional distribution problem for a perishable product is examined, under the important assumption that younger units are issued first (LIFO) to satisfy the demands of the customers at the locations. Optimal and approximately optimal allocation policies for two alternative distribution systems are derived. Their properties are discussed, and comparisons are made with the equivalent policies in a FIFO environment.     

Comparison of maintenance policies with monotone failure rate distributions

We compare different maintenance policies assuming that the system lifetime has either increasing failure rate (IFR), or decreasing failure rate (DFR) distribution. We show that these assumptions yield strongly stochastic comparisons between the process' intensities. This yields weaker stochastic comparison between the processes than the stochastic comparison that hold when the system lifetime is new better than used (NBU) or new worse than used (NWU). Copyright © 2002 John Wiley & Sons, Ltd.     

Platform modelling and scheduling game with multiple intelligent cloud-computing pools for big data

We develop a generic game platform that can be used to model various real-world systems with multiple intelligent cloud-computing pools and parallel-queues for resources-competing users. Inside the platform, the software structure is modelled as Blockchain. All the users are associated with Big Data arrival streams whose random dynamics is modelled by triply stochastic renewal reward processes (TSRRPs). Each user may be served simultaneously by multiple pools while each pool with parallel-servers may also serve multi-users at the same time via smart policies in the Blockchain, e.g. a Nash equilibrium point myopically at each fixed time to a game-theoretic scheduling problem. To illustrate the effectiveness of our game platform, we model the performance measures of its internal data flow dynamics (queue length and workload processes) as reflecting diffusion with regime-switchings (RDRSs) under our scheduling policies. By RDRS models, we can prove our myopic game-theoretic policy to be an asymptotic Pareto minimal-dual-cost Nash equilibrium one globally over the whole time horizon to a randomly evolving dynamic game problem. Iterative schemes for simulating our multi-dimensional RDRS models are also developed with the support of numerical comparisons.     

两比例失效率元件组成串联系统元件冗余与系统冗余的随机比较

针对两个比例失效率元件组成的串联系统,在热冗余的情形下,讨论了串联系统的元件冗余与系统冗余两种方案,并基于随机序的方法,对普通随机序、失效率序、反失效率序建立了元件冗余优于系统冗余的随机比较理论.     

Achieving matrix consistency in AHP through linearization

Matrices used in the analytic hierarchy process (AHP) compile expert knowledge as pairwise comparisons among various criteria and alternatives in decision-making problems. Many items are usually considered in the same comparison process and so judgment is not completely consistent – and sometimes the level of consistency may be unacceptable. Different methods have been used in the literature to achieve consistency for an inconsistent matrix. In this paper we use a linearization technique that provides the closest consistent matrix to a given inconsistent matrix using orthogonal projection in a linear space. As a result, consistency can be achieved in a closed form. This is simpler and cheaper than for methods relying on optimisation, which are iterative by nature. We apply the process to a real-world decision-making problem in an important industrial context, namely, management of water supply systems regarding leakage policies – an aspect of water management to which great sums of money are devoted every year worldwide.     

Replacement Policies under Minimal Repair

In many situations where system failures occur the concept of ‘minimal repair’ is important. A minimal repair occurs when the failed system is not treated so as to return it to ‘as new’ condition but is instead returned to the average condition for a working system of its age. Examples include complex systems where the repair or replacement of one component does not materially affect the condition of the whole system.For a system with decreasing reliability it will become increasingly expensive to maintain operation by minimal repairs, and the question then arises as to when the entire system should be replaced. We consider cases where the failure distribution can be modelled by the Weibull distribution. Two policies have been suggested for this case. One is to replace at a fixed time and the other is to replace at a fixed number of failures. We consider a third policy, to replace at the next failure after a fixed time, and show that it is optimal.Expressions to decide the replacement point and the cost of this policy are derived. Unfortunately these do not give rise to explicit representations, and so they are used to provide extensive numerical comparisons of the policies in a search for effective explicit approximations. Conclusions are drawn from these comparisons regarding the relative effectiveness of the policies and approximations.     

Mathematical Analysis of Preventive Maintenance Schemes

A new approach is proposed for the maximization of profit by optimal scheduling of machinery. Only one objective function (profit) is used instead of two (availability and cost). The latter approach inevitably resulted in suboptimization. In addition, the "single objective function" approach naturally lends itself to comparisons of efficiency between any preventive maintenance policies. Optimal solutions were found in order to compare the efficiency of the commonly used policies of age and block replacement. Numerical results show that age replacement is always more profitable. Optimal solutions for these two maintenance policies were also found in the specific case where a maintenance repair is superior in quality to a breakdown repair. Finally, the physical law of increasing entropy, applied to the failure rate concept, leads to the conclusion that preventive maintenance should always be considered.     

Comments on: A comparative analysis for determining optimal price and order quantity when a sale increases demand

Although the net present value (NPV) criterion is theoretically the correct approach to developing optimal inventory policies, in the classical EOQ case, the average profit criterion generates solutions that are practically identical to those resulting from the NPV criterion. Nevertheless, a recent paper suggests that, when the demand for a product is price-elastic and a wholesaler offers a one-time-only price discount, use of the average profit criterion may obtain policies that are drastically suboptimal compared to the policies obtained by using the NPV criterion. We show that this suggestion is based on inaccurate models and inconsistent comparisons. Although in cases of large one-time-only discounts, there may be significant differences in the policies and consequences resulting from the two criteria, such large discounts are unrealistic. Furthermore, the larger the discount, the less practicable are the optimal order quantities based on either one of these criteria. Thus, in most real-life situations, the use of the average profit criterion does not result in serious suboptimization. In these situations, what may be important is not whether a retailer uses the NPV criterion or the average profit criterion, but whether the retailer can and does implement the optimal decisions resulting from the use of either criterion.     

气候政策的经济环境效应分析与比较—基于碳税、许可交易和总量控制的动态微分博弈

基于产品差别化假设,建立双寡头动态微分博弈模型,比较碳税和许可交易以及总量控制3种气候政策的经济环境效应.研究发现,不同气候政策对两国的经济效应不同.进一步研究还发现,在企业产品差别化竞争时,从碳排放流量来看,碳税政策和许可交易政策与总量控制政策之间没有严格的优劣之分;碳排放存量对碳税政策最敏感.从碳存量对政策的边际影响来看,许可交易政策与总量控制政策是相同的,而碳税政策与之相反.当两国生产的产品完全同质时,从均衡碳排放流量和碳排放存量来看,许可交易政策最优,总量控制政策次之,碳税政策最差.若政府单纯以控制碳排放量为目的,许可交易政策是最佳选择.     

Stochastic comparisons for time transformed exponential models

Different sufficient conditions for stochastic comparisons between random vectors have been described in the literature. In particular, conditions for the comparison of random vectors having the same copula, i.e., the same dependence structure, may be found in Müller and Scarsini (2001). Here we provide conditions for the comparison, in the usual stochastic order sense and in other weaker stochastic orders, of two time transformed exponential bivariate lifetimes having different copulas. Some examples of applications are provided too.     

Stochastic Approximation in Real Time: A Pipe Line Approach

1.IntroductionTheobjectiveofthisworkistostudystochasticapproximationinrea1time.Apipelineapproachissuggested.Asymptoticpropertiesoftheprocedurearedeve1oped,andcomparisonsofrateofconvergencewiththeclassicalalgorithmsaremade.LetxeE',andf(.):EL-FL-Thetraditio…     

A simulation of the impacts of dynamic price management for perishable foods on retailer performance in the presence of need-driven purchasing consumers

Numerous studies have investigated dynamic pricing for perishable products. The models have been designed to determine an optimal pricing structure and improve retailer performance. Previous studies on pricing models for perishable products have considered various assumptions of consumer demand and purchasing behaviour from deterministic and stochastic price-dependent demands to myopic and strategic consumer purchasing behaviour. They have not, however, considered consumer demand in reaction to a situation where the display stock of a particular product has different qualities (such as shelf-life) and prices available at the same time. This is particularly applicable in the analysis of dynamic pricing models for perishable foods. In this paper, we investigate the impact of frequency of discount during a product’s selling period on retailer performance, by considering changes in consumer purchasing behaviour in response to the display stock of a particular food product having different remaining shelf-life and prices. On the basis of a literature review and data obtained from interviews with food retailers, a simulation study is performed to compare the performance of different pricing policies. The results demonstrate the benefits gained by adopting more dynamic price policies.     

SIMULATING COST-EFFECTIVE WETLANDS RESERVES: A COMPARISON OF POSITIVE AND NORMATIVE APPROACHES

A conceptual model of farmer behavior is used to develop analytical expressions for the costs of wetland policies in the United States. An empirical study based on the model compares normative and positive cost estimates for accomplishing a specific policy and shows that these two modeling strategies yield very different cost estimates from the same basic data. Because models such as these are frequently used to support budget requests for government programs, the choice of modeling strategy can influence whether program goals can be accomplished with the funds requested.     

Effect of Data Transformations on Predictive Risk Indicators

Risk indicators used in many applications usually involve certain transformations of the variables of interest, such as averages or maxima over given time periods or spatial regions, threshold exceedances, etc., or a combination of them. A common practice is to predict these indicators by applying the same type of transformation on the sample data, that is, the ??historical?? values of the same indicators are used as the sample information set. In this work, the loss of information derived from the transformations defining the sample set is studied for different indicators and considering a flexible covariance model separating fractal dimension and memory. The evaluations and comparisons are performed in terms of predictive mutual information based on Shannon??s entropy. The results obtained for different scenarios suggest that, depending on the type of risk indicator considered and the dependence structure of the process of interest, the changes in terms of predictive information using diverse transformations of the observations may be substantial.