Enhancing capacity planning through forecasting: An integrated tool for maintenance of complex product systems

Despite the extensive amount of data generated and stored during the maintenance capacity planning process, Maintenance, Repair, and Overhaul (MRO) organizations have yet to explore their full potential in forecasting the required capacity to face future and unprecedented maintenance interventions. This paper explores the integration of time series forecasting capabilities in a tool for maintenance capacity planning of complex product systems (CoPS), intended to value data that is routinely generated and stored, but often disregarded by MROs. State space formulations with multiplicative errors for the simple exponential smoothing (SES), Holt’s linear method (HLM), additive Holt-Winters (AHW), and multiplicative Holt-Winters (MHW) are assessed using real data, comprised of 171 maintenance projects collected from a major Portuguese aircraft MRO. A state space formulation of the MHW, selected using the bias-corrected Akaike information criterion (AICc), is integrated in a Decision Support System (DSS) for capacity planning with probabilistic inference capabilities and used to forecast the workload probability distribution of a future and unprecedent maintenance intervention. The developed tool is validated by comparing forecasted values with workloads of a particular maintenance intervention and with a model simulating current forecasting practices employed by MROs.     

Growth,deficits and uncertainty: Theoretical aspects and empirical evidence from a panel of 27 countries

We examine the relationship between fiscal deficits and per-capita income growth in a panel of 27 European countries, allowing for perceived risks, in terms of fiscal sustainability, associated with additional government spending. Such risks are proxied by the conditional variability of manufacturing production and stock market returns and by the unconditional variability of two survey-based economic-sentiment indicators. To help clarifying how fiscal variables impact on growth and to provide a point of reference for the interpretation of the empirical results a structural growth model is first identified. We find evidence of an asymmetric relationship, in that fiscal deficits give rise to adverse growth effects if they coincide with high uncertainty regarding the prospects of the economy and no significant negative growth effects in the low-uncertainty case.     

Economic uncertainty,oil prices,hedging and U.S. stock returns of the airline industry

This paper examines the impacts of economic policy uncertainty and oil price shocks on stock returns of U.S. airlines using both industry and firm-level data. Our empirical approach considers a structural vector-autoregressive model with variables recognized to be important for airline returns including jet fuel price volatility. Empirical results confirm that oil price increase, economic uncertainty and jet fuel price volatility have significantly adverse effect on real stock returns of airlines both at industry and at firm level. In addition, we also find that hedging future fuel purchase has statistically positive impact on the smaller airlines. Our results suggest policy implications for practitioners, managers of airline industry and commodity investors.     

SZJ-1三轴智能校验台标准装置测量不确定度的评定方法

简要介绍了建立SZJ-1三轴智能校验台标准装置的必要性及原理框图。详细论述了其测量不确定度的评定方法。并对标准装置的测量不确定度进行了验证。     

Assessing horizontal mergers under uncertain efficiency gains

The analysis of horizontal mergers hinges on a tradeoff between unilateral effects and efficiency gains. We examine the role of uncertainty in this tradeoff. In theory, the attitude towards uncertainty depends on the curvature of the social objective function. On the one hand, adjustment effects, both on the consumers' and firms' sides, tend to make consumers' surplus and firms' profits convex. On the other hand, pass-through effects may act in the opposite direction. We show that convexity prevails in a number of situations, including the most general linear demand model. Implications for empirical merger analysis are exposed.     

Scenarios of the organic food market in Europe

Scenario analysis is a qualitative tool for strategic policy analysis that enables researchers and policymakers to support decision making, and a systemic analysis of the main determinants of a business or sector. In this study, a scenario analysis is developed regarding the future development of the market of organic food products in Europe. The scenario follows a participatory approach, exploiting potential interactions among the relevant driving forces, as selected by experts. Network analysis is used to identify the roles of driving forces in the different scenarios, and the results are discussed in comparison with the main findings from existing scenarios on the future development of the organic sector.     

CEO环境不确定性感知与企业创新模式选择关系研究

基于高阶理论与调节焦点理论,通过中国373家企业问卷调查数据,探讨CEO环境不确定性感知对企业创新模式选择的影响机制。结果表明：CEO环境不确定性感知对企业渐进性创新与突破性创新均具有显著正向影响;高管团队行为整合在CEO环境不确定性感知与企业创新间发挥部分中介作用;CEO特质调节焦点正向调节CEO环境不确定性感知与高管团队行为整合之间的关系,同时正向调节上述中介机制。     

An optimization approach for brass casting blending problem under aletory and epistemic uncertainties

A critical process in brass casting is the determination of the materials and their quantities to be added into the blend. The reason of being critical is the uncertainty about metal percentages in scrap raw materials. In this paper, the aleatory and epistemic uncertainties, which are modeled by using probability and possibility theory, respectively, have been handled simultaneously in a blending optimization problem for brass casting and a solution approach that transforms the possibilistic uncertainties into probabilistic ones is proposed. A numerical example is performed by the data supplied from MKE brass factory in Turkey. The results of the example have showed that the proposed approach can be effectively used for solving blending problem including aleatory and epistemic uncertainties in brass casting and other scrap based production process.     

经济政策不确定性、区域经济复杂度与企业创新行为

构建包含宏观经济政策不确定性指标、区域经济复杂度和上市公司特征变量“宏观-区域-企业”的实证面板数据，在理论分析经济政策不确定性对企业创新行为作用机理的基础上，以区域经济复杂度为视角，对经济政策不确定性与企业创新行为作用机制进行再检验。研究发现：经济政策不确定性对企业创新存在正向激励综合效应，同时，区域经济复杂度不仅能够促进企业创新行为，而且能够强化经济政策不确定性对企业创新行为的影响即抑制负向作用而强化正向作用。考虑内生性，通过替换核心变量检验稳健性以保证研究结论可靠，并且，研究企业特征发现，高科技企业和非高科技企业存在差异。     

Universal type structures with unawareness

Infinite hierarchies of awareness and beliefs arise in games with unawareness, similarly to belief hierarchies in standard games. A natural question is whether each hierarchy describes the playerʼs awareness of the hierarchies of other players and beliefs over these, or whether the reasoning can continue indefinitely. This paper constructs the universal type structure with unawareness where each type has an awareness level and a belief over types. Countable hierarchies are therefore sufficient to describe all uncertainty in games with unawareness.