大型建筑工程项目资源配置模型及策略研究——基于系统动力学的建模和仿真

大型建筑工程项目多类型资源的有效配置,是现阶段项目管理理论与工程管理实践面临的关键问题,特别是在考虑工艺顺序和间歇时间的工作可操作性特点,以及多资源之间反馈影响的情况下。通过整合挣值法和系统动力学理论,在分析资源可用性和工作可操作性之间因果关系的基础上,本文构建了大型建筑工程项目多资源配置的系统动力学模型。以上海市重大工程投资统计数据作为模型参数依据,模型的仿真结果表明:建筑工程项目不同类型资源其配置重要性与系统影响性存在显著差异,在制定资源配置策略时应同时考虑项目运作方式的特征与多资源之间的匹配,资源不匹配则容易导致资源配置系统失去稳态或策略失效。这为进一步研究项目管理中多资源配置提供了理论参考和实践支持。     

一般均衡理论视角下绿色金融的减排效应研究：从模型构建到实证检验

绿色金融是否能够有效促进碳减排？其内在机制是什么？在碳达峰与碳中和的时代目标下,科学、严谨地回答这一问题意义重大。本文将经典理论与最新前沿相结合,提出绿色金融能够通过促进绿色技术进步帮助碳减排的理论假说。构建带有碳排放约束并内生减排技术进步的一般均衡模型,解释了绿色金融通过支持技术进步实现碳减排的内在机制,并提供了基于中国省级面板数据的实证证据。本文的研究从理论和实证两个维度论证了绿色金融对碳减排的影响,指出支持技术创新是绿色金融发挥减排效应的重要机制。因而在发展绿色金融的过程中,注重金融资源的实际用途,有效支持减排技术更新,比单纯限制高排放行业的金融资源获取更加有效。同时,理论分析表明,绿色金融并非越多越好,而是存在最优规模。在积极推动绿色金融发展的同时,依然需要注重统筹规划,避免金融“过绿”带来不必要的损失。     

Quantifying Potential Health Impacts of Cadmium in Cigarettes on Smoker Risk of Lung Cancer: A Portfolio-of-Mechanisms Approach

This article introduces an approach to estimating the uncertain potential effects on lung cancer risk of removing a particular constituent, cadmium (Cd), from cigarette smoke, given the useful but incomplete scientific information available about its modes of action. The approach considers normal cell proliferation; DNA repair inhibition in normal cells affected by initiating events; proliferation, promotion, and progression of initiated cells; and death or sparing of initiated and malignant cells as they are further transformed to become fully tumorigenic. Rather than estimating unmeasured model parameters by curve fitting to epidemiological or animal experimental tumor data, we attempt rough estimates of parameters based on their biological interpretations and comparison to corresponding genetic polymorphism data. The resulting parameter estimates are admittedly uncertain and approximate, but they suggest a portfolio approach to estimating impacts of removing Cd that gives usefully robust conclusions. This approach views Cd as creating a portfolio of uncertain health impacts that can be expressed as biologically independent relative risk factors having clear mechanistic interpretations. Because Cd can act through many distinct biological mechanisms, it appears likely (subjective probability greater than 40%) that removing Cd from cigarette smoke would reduce smoker risks of lung cancer by at least 10%, although it is possible (consistent with what is known) that the true effect could be much larger or smaller. Conservative estimates and assumptions made in this calculation suggest that the true impact could be greater for some smokers. This conclusion appears to be robust to many scientific uncertainties about Cd and smoking effects.     

治污减排对经济发展影响的最新研究进展及启示

治污减排是中国调整经济结构、转变发展方式的突破口,必须同时实现节约资源、减少污染和促进发展的多重目标。中国的治污减排问题非常复杂、没有现成经验可循。针对环境、经济、能源之间的相互影响,国内外已有丰富的研究成果。本文试图梳理治污减排对经济影响方面的已有研究,为深入分析、研究中国的环境经济问题提供基础。     

主要排放部门的减排责任分担研究:基于全局成本有效的分析

运用中国能源与环境政策分析模型(CEEPA),从经济全局成本有效的角度,分析了一定减排约束下中国主要排放部门宜分担的减排责任及其减排行为。研究发现,基于排放量进行减排责任部门分担是有助于整体成本的,但对煤炭和运输仓储部门宜做出调整;随着减排目标的增加,应增添运输仓储部门的减排配额比例,减少煤炭部门的减排配额比例;短期内不宜对各部门尤其是煤炭部门设置较高的减排目标。     

An Assessment of the Italian 2007 Complementary Social Security Reform: A Simulation Approach

In this paper we aim at assessing the outcomes of the 2007 Italian reform of the complementary social security scheme and at identifying the determinants behind them. The reform provided workers with relevant incentives to switch the investment of about 7 per cent of their gross yearly wages from a firm‐managed scheme (which took the form of a termination indemnity payment, the Trattamento di Fine Rapporto scheme) to an external pension fund. We provide a theoretical framework to model the workers' problem of choosing between these two different forms of complementary social security schemes and we then perform an agent‐based simulation taking into account all the details of the reform. Differently from previous contributions, we stress the impact that the investment decision has on the financial health of firms and, consequently, on workers' employment stability. Our simulations are able to replicate the Italian data in terms of adhesion rates to complementary social security and also to identify some of the key determinants of that outcome, such as fiscal incentives, individual preferences, the working of both the Italian labour and the financial markets and the productive structure of the Italian economy.     

Labour Market Policies in Times of Crisis: A Reaction Function Approach for the Period 1985–2010

This article examines the reaction function of labour market expenditure to unemployment in 24 OECD countries, over the period 1985–2010, using the OECD panel data. The level of public debt is also introduced as a factor that is likely to influence these expenditures. Using a fixed‐effect model with interaction terms, this research focuses on two periods of crisis (1992–93 and 2007–09). The results confirm the counter‐cyclical variation of labour market policy expenditures. Nevertheless, the sensitivity of labour market expenditure to the economic cycle has in general decreased and the policy mix has changed. This could result from the important labour market reforms undertaken in the last 20 years.     

A Health Risk Benchmark for the Neurologic Effects of Styrene: Comparison with NOAEL/LOAEL Approach

Benchmark dose (BMD) analysis was used to estimate an inhalation benchmark concentration for styrene neurotoxicity. Quantal data on neuropsychologic test results from styrene-exposed workers [Mutti et al. (1984). American Journal of Industrial Medicine, 5, 275-286] were used to quantify neurotoxicity, defined as the percent of tested workers who responded abnormally to > or = 1, > or = 2, or > or = 3 out of a battery of eight tests. Exposure was based on previously published results on mean urinary mandelic- and phenylglyoxylic acid levels in the workers, converted to air styrene levels (15, 44, 74, or 115 ppm). Nonstyrene-exposed workers from the same region served as a control group. Maximum-likelihood estimates (MLEs) and BMDs at 5 and 10% response levels of the exposed population were obtained from log-normal analysis of the quantal data. The highest MLE was 9 ppm (BMD = 4 ppm) styrene and represents abnormal responses to > or = 3 tests by 10% of the exposed population. The most health-protective MLE was 2 ppm styrene (BMD = 0.3 ppm) and represents abnormal responses to > or = 1 test by 5% of the exposed population. A no observed adverse effect level/lowest observed adverse effect level (NOAEL/LOAEL) analysis of the same quantal data showed workers in all styrene exposure groups responded abnormally to > or = 1, > or = 2, or > or = 3 tests, compared to controls, and the LOAEL was 15 ppm. A comparison of the BMD and NOAEL/LOAEL analyses suggests that at air styrene levels below the LOAEL, a segment of the worker population may be adversely affected. The benchmark approach will be useful for styrene noncancer risk assessment purposes by providing a more accurate estimate of potential risk that should, in turn, help to reduce the uncertainty that is a common problem in setting exposure levels.     

A Systems Approach to the Policy‐Level Risk Assessment of Exotic Animal Diseases: Network Model and Application to Classical Swine Fever

Exotic animal diseases (EADs) are characterized by their capacity to spread global distances, causing impacts on animal health and welfare with significant economic consequences. We offer a critique of current import risk analysis approaches employed in the EAD field, focusing on their capacity to assess complex systems at a policy level. To address the shortcomings identified, we propose a novel method providing a systematic analysis of the likelihood of a disease incursion, developed by reference to the multibarrier system employed for the United Kingdom. We apply the network model to a policy‐level risk assessment of classical swine fever (CSF), a notifiable animal disease caused by the CSF virus. In doing so, we document and discuss a sequence of analyses that describe system vulnerabilities and reveal the critical control points (CCPs) for intervention, reducing the likelihood of U.K. pig herds being exposed to the CSF virus.