Demand forecasting and order planning for humanitarian logistics: An empirical assessment

Humanitarian aid organizations are most known for their short-term emergency relief. While getting aid items to those in need can be challenging, long-term projects provide an opportunity for demand planning supported by forecasting methods. Based on standardized consumption data of the Operational Center Amsterdam of Médecins Sans Frontières (MSF-OCA) regarding nineteen longer-term aid projects and over 2000 medical items consumed in 2013, we describe and analyze the forecasting and order planning process. We find that several internal and external factors influence forecast and order planning performance, be it indirectly through demand volatility and safety markup. Moreover, we identify opportunities for further improvement for MSF-OCA, and for humanitarian logistics organizations in general.     

Scale efficiency and homotheticity: equivalence of primal and dual measures

We address the issue of equivalence of primal and dual measures of scale efficiency in general production theory framework. We find that particular types of homotheticity of technologies, which we refer to here as scale homotheticity, provide necessary and sufficient condition for such equivalence. We also identify the case when the scale homotheticity is equivalent to the homothetic structures from Shephard (Theory of cost and production functions, Princeton studies in mathematical economics. Princeton University Press, Princeton, 1970).     

Consistent order selection with strongly dependent data and its application to efficient estimation

Order selection based on criteria by Akaike (IEEE Trans. Automat. Control AC-19 (1974) 716), AIC, Schwarz (Ann. Stat. (1978) 461), BIC or Hannan and Quinn's (J. R. Stat. Soc. Ser. B (1979) 190) HIC is often applied in empirical examples. They have been used in the context of order selection of weakly dependent ARMA models, AR models with unit or explosive roots and in the context of regression or distributed lag regression models for weakly dependent data. On the other hand, it has been observed that data exhibits the so-called strong dependence in many areas. Because the interest to this type of data, our main objective in this paper is to examine order selection for a distributed lag regression model that covers in a unified form weak and strong dependence. To that end, and because the possible adverse properties of the aforementioned criteria, we propose a criterion function based on the decomposition of the variance of the innovations of the model in terms of their frequency components. Assuming that the order of the model is finite, say p₀, we show that the proposed criterion consistently estimates p₀. In addition, we show that adaptive estimation for the parameters of the model is possible without knowledge of p₀. Finally, a small Monte-Carlo experiment is included to illustrate the finite sample performance of the proposed criterion.     

An identity for the product moments of order statistics

A general identity for the product moments of successive order statistics is given, which is valid in a class of probability distributions including Weibull, Pareto, exponential and Burr distributions.     

砌体结构裂缝的成因及控制措施

结构裂缝控制看来是一个比较简单、普遍存在的问题,但却是一门与力学、热工学、材料学等专业知识关系十分密切的、复杂的综合性学科,是建筑工程中确保工程质量不容忽视的重要环节。在该领域中,目前国内尚无统一的规范和技术指标可循。文章仅从一般理论和多年实践经验入手,通过对砌体结构裂缝成因的分析,阐述控制裂缝的措施。     

An analytical theory of multi-echelon production/distribution systems

In this paper, we study inventory control problems arising in multi-echelon production/distribution chains. In these chains, material is delivered by outside suppliers, proceeds through a number of manufacturing stages, and is distributed finally among a number of local warehouses in order to meet market demand. Each stage requires a fixed leadtime; furthermore, we assume a stochastic, stationary end-item demand process.
The problem to balance inventory levels and service degrees can be modelled and analyzed by defining appropriate cost functions. Under an average cost criterion, we study the three most important structures arising in multi-echelon systems: assembly systems, serial systems and distribution systems. For all three systems, it is possible to prove exact decomposition results which reduce complex multi-dimensional control problems to simple one-dimensional problems. In addition, we establish the optimality of base-stock control policies.     

Estimation of the parameters of log-gamma distribution using order statistics

In this work we propose a technique of estimating the location parameter μ and scale parameter σ of log-gamma distribution by U-statistics constructed by taking best linear functions of order statistics as kernels. The efficiency comparison of the proposed estimators with respect to maximum likelihood estimators is also made.     

高职物流管理专业订单培养模式实践研究

自从教育部教高[2006]16号文件颁布以来,高职的订单培养问题一直是高职教育的一个热点,但针对物流管理这类经管专业在具体的实践过程中出现了不少的问题,如何解决这些问题一直是经管类专业的重要课题。通过多年的实践,我们在对物流管理专业的订单培养过程中灵活根据用人单位的需要不断地进行人才订单培养模式的研究与实践,目前已经形成了全过程订单培养、半过程订单培养、推荐式订单培养三种主要的订单培养模式。文中对这些实践经验进行了研究与总结。     

On characterizations of distributions by expected values of order statistics and record values with gap

In this paper, we obtain some recurrence relationships for conditional expectations of nonadjacent order statistics and record values when the distribution function is absolutely continuous, and we prove that the distribution function is uniquely determined by the distribution of conditioned record values and by the expected values of these records. Further, different distributions are characterized by these relationships.     

Optimizing order policy and credit term for items with inventory-level-dependent demand under trade credit limit

Under the combined effects of inventory-level-dependent demand (ILDD) and trade credit, the retailer is able to order more quantities to stimulate market demand. However, from the supplier's perspective, two important issues are lacking sufficient attention. First, during the credit period, the retailer's higher order quantities imply increases in both the retailer's account payable and the supplier's opportunity cost of capital. Second, given the supplier's fixed production rate, the increased market demand may drive the capacity utilization to be variable. Thus, by formulating a supplier-dominated system, this paper incorporates trade credit limit (TCL) to address its effects on optimal policies vis-à-vis the item with ILDD. Specifically, three indicators can be proposed to reveal which type of financing policy the retailer should choose. Moreover, based on TCL, the supplier can effectively manage the retailer's order quantity and the corresponding account payable. Additionally, the retailer's maximum allowable order quantity is developed to ensure that the supplier can supply the retailer's order quantity on time. Furthermore, when the effects of ILDD become more significant, the manufacturer will reduce the maximum allowable order quantity to control the retailer's order incentive.     

人民币升值压力的演进、成因分析和应对措施

本文分析了人民币汇率升值压力演进历程的三个阶段,并结合中国的贸易收支、国内外利差和中国的通货膨胀情况三类经济基本面因素研究了人民币升值压力的来源。分析发现近期人民币汇率已经不存在大幅低估甚至可能高估,无需一次性大幅升值。因此,中国必须认清升值压力的本质,继续坚持＂自主性＂掌控人民币汇率形成机制的改革路径,必要时可实施反制措施。     

Repeated measures and longitudinal data analysis using higher‐order entropies

This paper implements the generalized maximum entropy (GME) method in longitudinal data setup to investigate the regression para meters and correlation among the repeated measurements. We derive the GME system using Shannon classical entropy as well as some higher‐order entropies assuming an autoregressive correlation structure. This method is illustrated using two simulated examples to study the effect of changing the support range and compare the performance of the GME approach with the classical estimation methods.     

The topological equivalence of the pareto condition and the existence of a dictator

The paper studies two standard properties of rules for aggregating individual into social preferences: non-dictatorship and the Pareto condition. Together with the condition of independence of irrelevant alternatives, these are the three basic axioms of Arrow's social choice paradox.We prove the topological equivalence between the Pareto condition and the existence of a dictator for continuous rules. The axiom of independence of irrelevant alternatives is not required.The results use a topological framework for aggregation introduced in Chichilnisky (1980), but under different conditions. In Chichilnisky (1980) rules are anonymous and respect unanimity. Since anonymity is strictly stronger than the condition of non-dictatorship, while respect of unanimity is strictly weaker than the Pareto condition, the two sets of conditions are not comparable.     

The equivalence of supporting software delegation and sales delegation

This paper considers a duopoly market with horizontally differentiated system goods to examine system owners' behaviors under supporting software delegation, in which owners of system firms use varieties of supporting software, coupled with profit, to evaluate their managers' performance. Supporting software delegation seems to induce managers to act more aggressively in price competition than sales delegation does; however, we prove that if two systems are compatible and the varieties of supporting software are determined by hardware owners' overall expenditure amount on software, then supporting software delegation is equivalent to sales delegation. Owners of system firms induce their managers to act less aggressively in hardware price competition by offering contracts with a negative weight on varieties of supporting software under supporting software delegation. We find that stronger network externalities do not reverse system owners' contracting behaviors under supporting software delegation. Finally, it is worth mentioning that hardware technologies are static in this paper. In other words, dynamic changes such as hardware evolution are not considered in our analysis.     

混凝土泵堵管故障分析及预防措施

泵送混凝土因作业速度快、生产效率高、劳动强度低而被施工单位广泛使用,但泵送过程中的堵管是经常出现的难以处理的问题。文章对泵送混凝土堵管的原因进行了分析,提出了解决办法和预防措施。     

The profit equivalence of mill and uniform pricing policies

In this note we point out a simple fact that seems to have been overlooked in the voluminous literature on mill pricing and uniform delivered pricing in location theory — the profit maximization problems involved are mathematically equivalent when the demand functions are linear.     

轻型木结构住宅的结构与施工

新式轻型木结构住宅从上世纪90年代由北美引入我国后．已在多处经济发达地区建造了数以百计的此类住宅建筑。介绍了轻型木结构住宅的工程概况,并阐述了轻型木结构体系中屋面、墙体和楼面结构的典型施工技术。     

浅析我国第四方物流发展的成因及措施

我国物流产业的真正提升必须通过第四方物流来完成。第四方物流对整合社会资源、降低物流成本、提高物流效率具有极其重要的作用。文中从现实角度出发,分析了第四方物流发展的成因,在此基础上提出了我国发展第四方物流的措施。     

铁路路基翻浆冒泥病害机理及整治

由于每年降雨的冲刷,导致路基基床翻浆冒泥这一现象已成为影响铁路安全和运营的顽疾,每年需花费巨资整治路基翻浆冒泥,严重影响了线路的正常运营和铁路的大提速。文章在探求路基翻浆冒泥的机理的基础上,对现有病害探测和维修检测的方法进行了分析,并对现有路基基床翻浆冒泥整治技术进行了对比研究。对比分析表明:路基翻浆冒泥是多个影响因素共同作用的结果,但同时不同路基翻浆冒泥产生的原因也有差别,因此,在对路基翻浆冒泥病害的整治中应具有针对性。     

The failure of Ricardian equivalence under dynastic altruism

This paper investigates the theoretical accuracy of the Barro [Barro, R.J., 1974. Are government bonds net wealth? Journal of Political Economy, 82, 1095–1117] debt neutrality proposition. We first identify a discrepancy between the transversality condition of a social planning problem and the one of altruistically linked overlapping generations. Then, this discrepancy is exploited to construct public debt policies which affect the competitive equilibrium allocation even when bequests are strictly positive in all periods: a violation of Ricardian equivalence.