基于数量柔性契约的双源应急物资采购定价模型

针对灾害事件发生的不确定性以及灾害发生后应急物资需求量的爆发式增长，本文设计了一个政府主导的基于数量柔性契约的双源应急物资采购模型。在存在一个现货市场的情况下，政府除了常规采购外，还会与供应方签订一份数量柔性契约，用以建立政企联合储备应急物资的合作关系。通过数理推导，本文发现灾害事件发生概率，政府自身储备量，现货市场采购价格会对双方决策产生重要影响，并给出三个影响因素在满足不同条件时政企双方的最优决策，同时进一步分析了这三个因素对政府采购成本与供应方利润的影响。最后，通过数值模拟的方式对所得结论进行了验证。本文的研究为政府与企业构建联合储备应急物资的合作关系提供了指导与依据。     

The Never‐ending Shift: A feminist reflection on living and organizing academic lives during the coronavirus pandemic

This article offers a feminist reflection written as a nocturnal stream of consciousness exposing the embodied, emotional and professional experience of living and working during a pandemic outbreak. Framed within a feminist approach, this personal narrative provides an example of the effects of such unexpected and unprecedented circumstances on personal and professional academic lives. Developed during the first stage of the (inter)national coronavirus pandemic, my reflections address issues of privilege; emotional labour; the virtual invasion of the home space within the current increasingly ambiguous space of ‘the workplace'; workload; and wellbeing. Further, I consider how the newly enforced flexible work measures based on online tools have turned current work–life dynamics into a ‘Never‐ending Shift'.     

Efficient Bayesian inference in generalized inverse gamma processes for stochastic volatility

This paper develops a novel and efficient algorithm for Bayesian inference in inverse Gamma stochastic volatility models. It is shown that by conditioning on auxiliary variables, it is possible to sample all the volatilities jointly directly from their posterior conditional density, using simple and easy to draw from distributions. Furthermore, this paper develops a generalized inverse gamma process with more flexible tails in the distribution of volatilities, which still allows for simple and efficient calculations. Using several macroeconomic and financial datasets, it is shown that the inverse gamma and generalized inverse gamma processes can greatly outperform the commonly used log normal volatility processes with Student’s t errors or jumps in the mean equation.     

China’s flexible overseas food strategy: food trade and agricultural investment between Southeast Asia and China in 1990–2015

Using the UN Comtrade database and multiple sources of agricultural investment data, this paper outlines the emerging patterns of food trade and agricultural investment between Southeast Asian countries and China. The paper shows that China has adopted a flexible overseas food strategy. First, China has increased food export and shifted its food trade with Southeast Asia from a dependent relationship towards a complementary relationship at the regional level in recent years. Second, China tends to adapt to the existing conditions of food production and trade in Southeast Asian countries instead of fundamentally altering them. Finally, Chinese overseas agricultural investment is less driven by domestic food demand but more oriented for profit making, and this gives it flexibility in diversifying investment. An adequate understanding of China’s flexible food strategy in bilateral and multilateral relationships holds implications for global food security.     

斜拉桥主梁损伤对车激索力响应的影响研究

以斜拉桥的损伤识别为目的,提出了一种索力比指标,研究了斜拉桥在车辆荷载激励下,主梁发生损伤时斜拉索索力比指标的变化规律。以实验室独塔斜拉桥试验模型为研究对象,基于ANSYS建立其空间板壳有限元模型,以单元刚度的折减模拟主梁损伤,对主梁在不同位置损伤、不同程度损伤两类工况下,车辆荷载激励下斜拉索的索力比指标变化进行了数值仿真。结果表明：车辆荷载激励下,斜拉索的索力比指标与主梁的损伤位置和损伤程度存在一定的对应关系。为后续基于车辆荷载激励下的索力响应指标识别斜拉桥损伤方法的研究提供了重要的参考,具有一定的理论意义。     

转型与整合——90年代前期长篇小说叙事语境及策略

针对耦合非线性混沌振子复杂的动力学行为,本文将Duffing振子和Van der Pol振子进行耦合,建立了Duffing振子和Van der Pol振子的耦合模型。与单个振子相比,耦合Duffing振子和Van der Pol振子表现出了更加丰富的动力学特性,采用Simulink仿真的方法,通过不同策动力幅值、不同耦合系数、不同频率下耦合非线性振子的相图和庞加莱截面图分析了耦合非线性振子的动力学行为,研究了耦合振子对微弱周期信号的敏感性和对噪声的免疫力,并将此模型应用于微弱信号检测的研究中。     

Oiling the wheels? Flexible labour markets and the migration industry

ABSTRACT

The growing commercialisation of migration, often through a multiplicity of labour market intermediaries, is an issue of increasing academic interest. We seek to contribute to an emerging research agenda on the migration industries by exploring how one of the key actors that constitutes it, recruitment agencies, sits at the nexus between flexible labour market structures and migrant labour. Interviews with U.K. labour providers and low-wage employers form the evidence base for an analysis of the strategies developed by recruiters to derive commercial gain from connecting the so-called ‘supply’ and ‘demand’ sides of the flexible international labour market. We seek to contribute to understandings of the analytical categories within migration systems by illustrating how the migration industry interacts with other key stakeholders to structure international migration.     

基于ANSYS的热成形模具结构优化

基于冲压成型工艺试验分析系统,针对模具内材料受热膨胀将对模具导向装置及结构造成干涉的问题,利用有 限元分析软件ANSYS对模内温度场进行热力耦合分析,得出各部分材料的热膨胀程度。为基于正向压边模架的模内加 热装置提供可靠的实验参数和热力学设计依据,提高了模具结构设计的合理性,达到优化设计的目的。     

教育发展与市场技术进步耦合的时空分异特征研究

教育发展与市场技术进步存在着密切的耦合关系。基于耦合理论,分析了教育发展与市场技术进步的耦合逻辑,并构建了分析教育发展与市场技术进步耦合协调的指标体系。通过实证研究发现,从时间维度上看,中国教育发展与市场技术进步尽管存在一定的关联度和耦合持续发展度,但关联度和强度不高。从区域维度上看,教育资源与产业资源分配的不均衡、经济基础差距、区域创新体系构建不完善等多种因素造成东部、中部和西部在教育发展与市场技术进步的耦合程度方面形成巨大差异,教育资源与产业资源分配的不匹配在一定程度上造成了教育发展与市场技术进步耦合度“东西较高,中部塌陷”的总体格局。基于理论和实证研究的结论,提出了促进教育发展与市场技术进步耦合发展的相关政策建议。     

Backward capacity-filtering for electronics Fabs

In electronics Fabs such as semiconductor Fabs and liquid crystal display (LCD) Fabs, which are capital-intensive, finite-capacity planning is critical to achieving full-capacity production and on-time production. However, existing finite-capacity planning methods do not adequately reflect the actual capacity profiles of an electronics Fab. In this paper, we propose a new Fab-level capacity-filtering procedure to generate finite-capacity plan: a backward capacity-filtering procedure for generating finite-capacity release plan. When developing the Fab-level filtering procedures, we use stage-level capacity-filtering algorithms as a key building block. In this study, we enhance the previous capacity-filtering algorithms proposed by one of the authors in order to facilitate the practical requirements of electronics Fabs. We apply the proposed capacity-filtering method to a modern LCD–TFT Fab in Korea. Performance analyses demonstrate that the proposed method is superior to existing methods.