Robust Markowitz mean‐variance portfolio selection under ambiguous covariance matrix

This paper studies a robust continuous‐time Markowitz portfolio selection problem where the model uncertainty affects the covariance matrix of multiple risky assets. This problem is formulated into a min–max mean‐variance problem over a set of nondominated probability measures that is solved by a McKean–Vlasov dynamic programming approach, which allows us to characterize the solution in terms of a Bellman–Isaacs equation in the Wasserstein space of probability measures. We provide explicit solutions for the optimal robust portfolio strategies and illustrate our results in the case of uncertain volatilities and ambiguous correlation between two risky assets. We then derive the robust efficient frontier in closed form, and obtain a lower bound for the Sharpe ratio of any robust efficient portfolio strategy. Finally, we compare the performance of Sharpe ratios for a robust investor and for an investor with a misspecified model.     

Microfoundations of companies' dynamic capabilities for environmentally sustainable innovation: Case study insights from high‐tech innovation in science‐based companies

To achieve sustainable development, companies are increasingly putting an emphasis on the creation and the promotion of environmentally sustainable innovations. Environmentally sustainable innovation often involves a significant shift in a new strategic direction. This paper studies this shift from a dynamic capabilities perspective and aims to identify the microfoundations of science‐based companies' dynamic capabilities for high‐tech environmentally sustainable innovations. It investigates the development of high‐tech environmentally sustainable innovations in two distinctive science‐based companies. To scholars, this study provides an in‐depth process analysis, over time, of how and why microfoundations of dynamic capabilities influence the development of a science‐based company's high‐tech environmentally sustainable innovations. To practitioners in science‐based firms, this process study can function as a frame of reference, enabling the tailoring of a strategy for high‐tech environmentally sustainable innovation.     

舾装作业中考虑周期驱动的虚拟单元多阶段动态调度研究

多品种小批量离散型生产企业面临的大量不确定因素会干扰其生产的连续性,其中,船舶生产由于其技术与管理特点在此类生产中具有典型性.本文将以船舶舾装生产为例,在保证设备负荷均衡及资源利用率的基础上,研究该环节的虚拟单元调度问题,以提高企业的生产效率.文章以最小运输距离为目标,在充分考虑瓶颈资源约束的基础上,构建周期驱动下分割计划期的数学模型,并以结合任务分配和时间约束的混合蚁群算法求解.通过在某船厂舾装环节的应用发现,本文所提方法能够有效降低当前舾装各作业的平均完成时间,具备可行性.     

动液面谱减法滤波

动液面滤波是油井检测动液面的关键技术之一。文章利用谱减法处理油井动液面信号,消除背景噪声的影响,并改进谱减法应用到动液面滤波,取得较好的滤波效果,从而提高对液面反射波位置的辨识能力。     

动态井点降水在沈阳地铁东～滂区间盾构井的应用

地表管井动态降水在沈阳地铁东~滂区间盾构井的应用,降水井的间距、井深、泵型、下泵深度、水泵开启时间控制,通过动态调整以上参数完成盾构井基坑开挖施工。     

How an international ambidexterity strategy can address the paradox perspective on corporate sustainability: Evidence from Chinese emerging market multinationals

Corporate sustainability (CS) is receiving considerable attention from emerging market multinational enterprises (EMNEs), playing an important role in the globalized market. However, theoretical and empirical knowledge about how EMNEs address CS is still scant, and the relationship between internationalization and CS has not been widely explored. This study aims to fill this gap, evaluating the relationship between an international ambidexterity strategy and CS in EMNEs, which highlighted the paradox perspective. Then we develop three hypotheses in which we argue how the dynamic capabilities underpinning international ambidexterity could be considered a driver of CS in EMNEs. We test the developed hypotheses against data from 300 Chinese EMNEs obtained by a survey. Our results contribute to shape ambidextrous international strategies and to consider CS as a springboard for the strategic intent to systematically and recursively outperform global competition. Testing a measurement scale of international ambidexterity, we suggest structural ambidexterity as a strategic option of internationalization that allows the achievement of economic, social, and environmental sustainability objectives.     

A simple characterisation for sustained growth

This article considers an inter-temporal optimisation problem in a general form and gives conditions ensuring the convergence to infinity of the economy. These conditions can be easily verified and applied for a large class of problems in the literature. Some applications for different economies are given as illustrative examples.     

Impact of oil price changes on Turkey’s exports

Substantial decline in oil prices observed since the second half of 2014 has brought forward discussions on the impact of oil prices on the external balance. This decline is expected to shift real income from oil exporter countries to oil importer countries. In this context, we study the effect of change in oil prices on Turkey’s exports taking into account the fact that Turkey’s export to oil exporting countries has approximately one-third share in total exports, while export to oil importing countries has a share of two-thirds. At the first step, we analyse the effect of oil prices on economic growth of trade partners of Turkey, where countries are grouped according to their net oil export position. We find that the effect of oil prices on different country groups’ growth is asymmetric. In the second stage, for two groups of countries, we estimate growth-export elasticity through Turkey’s export demand function. Finally, we calculate the net effect of oil prices on exports considering different income effects caused by oil price change on each country groups. Results indicate that the net effect of oil prices on the exports is limited given the current export shares.     

常州装备制造业与生产性服务业动态匹配优化路径研究

装备制造业与生产性服务业动态匹配是二者之间密切互动的表现,也是二者协同发展互动升级的重要手段。通过对常州装备制造业与生产性服务业发展现状、动态匹配中存在的问题进行梳理和分析,进而从装备制造业与生产性服务业发展的中间组织的培育与促进、市场环境营造、匹配程度提升两个维度,九个方面,对两者动态匹配路径进行设计。     

Investigating first‐stage exchange rate pass‐through: Sectoral and macro evidence from euro area countries

In this paper, we evaluate the first‐stage pass‐through, namely the responsiveness of import prices to the exchange rate changes, for a sample of euro area (EA) countries. Our study aimed to shed further light on the role of microeconomic factors versus macroeconomic factors in influencing the extent of the exchange rate pass‐through (ERPT). As a first step, we conduct a sectoral analysis using disaggregated import prices data. We find a much higher degree of pass‐through for more homogeneous goods and commodities, such as oil and raw materials, than for highly differentiated manufactured products, such as machinery and transport equipment. Our results confirm that cross‐country differences in pass‐through rates may be due to divergences in the product composition of imports. The higher share of imports from sectors with lower degrees of pass‐through, the lower ERPT for an economy will be. In a next step, we investigate for the impact of some macroeconomics factors or common events experienced by EA members on the extent of pass‐through. Using the system generalised method of moments within a dynamic panel‐data model, our estimates indicate that decline of import‐price sensitivity to the exchange rate is not significant since the introduction of the single currency. Our findings suggest instead that the weakness of the euro during the first 3 years of the monetary union significantly raised the extent of the ERPT. This outcome could explain why the sensitivity of import prices has not fallen since 1999. We also point out a significant role played by the inflation in the Eurozone, as the responsiveness of import prices to exchange rate fluctuations tends to decline in a low and more stable inflation environment. Overall, our findings support the view that the extent of pass‐through is comprised of both macro‐ and microeconomic aspects that policymakers should take into account.