The Economic Value of a Sustainable Supply Chain

The economic rationale to operate a global supply chain in a sustainable manner is developed. Arguments are made based on marketing, finance, and production theories that by engaging in socially responsible behavior the firm will increase sales, decrease costs, reduce financial risk, and increase profits, which will ultimately increase returns to the firm's shareholders. A model is developed of the mechanism by which modern production methods such as lean production and quality management result in sustainable corporate behavior that, in the long run, translates into higher stock valuations. The production effects cause marketing and financial risk effects that are complementary, and all three channels of influence synergistically result in higher stock values in the model. These effects also provide important benefits to other stakeholders of the firms including employees, customers, the environment, and the community. An important ethical issue in global supply chains is working conditions in foreign plants often leading to allegations of sweatshop labor conditions. This issue is used to illustrate how lean production practices can affectconsumers, employees, and financial risk. Conclusions from the sweatshop labor issue are shown to apply to other sustainability issues as well.     

Technology Choice and Capacity Portfolios under Emissions Regulation

We study the impact of emissions tax and emissions cap‐and‐trade regulation on a firm's technology choice and capacity decisions. We show that emissions price uncertainty under cap‐and‐trade results in greater expected profit than a constant emissions price under an emissions tax, which contradicts popular arguments that the greater uncertainty under cap‐and‐trade will erode value. We further show that two operational drivers underlie this result: (i) the firm's option not to operate, which effectively right‐censors the uncertain emissions price; and (ii) dispatch flexibility, which is the firm's ability to first deploy its most profitable capacity given the realized emissions price. In addition to these managerial insights, we also explore policy implications: the effect of emissions price level, and the effect of investment and production subsidies. Through an illustrative example, we show that production subsidies of higher investment and production cost technologies (such as carbon capture and storage technologies) have no effect on the firm's optimal total capacity when firms own a portfolio of both clean and dirty technologies, but that investment subsidies of these technologies increase the firm's total capacity, conditionally increasing expected emissions. A subsidy of a lower production cost technology, on the other hand, has no effect on the firm's optimal total capacity in multi‐technology portfolios, regardless of whether the subsidy is a production or investment subsidy.     

对偶性在线性规划预处理中的应用分析

在当今大数据背景下,从实际应用中抽象出来的线性规划问题的规模越来越大,复杂性越来越高,因此数据预处理技术在线性规划问题求解中的重要性日渐突显。对偶性不仅有助于原始问题的算法（如对偶单纯形法）求解,而且是进行算法求解前的预处理步的重要组成部分。针对后者,本文基于有上下界的线性规划模型,详细分析总结了将对偶性应用于预处理中的两种方法：优先列和比例列的处理,并利用无效约束的概念证明了弱优先列的性质,最后应用C语言将预处理方法进行编程实现,以国际通用题库中变量个数大于1500的标准线性规划问题为实例进行测试。实例测试结果表明：（1）对于一般线性规划问题而言,对偶性在预处理中的应用能够有效减小问题规模,一方面体现在直接减少问题的变量数和非零元数,另一方面通过影响其他预处理方法间接减少问题的约束个数;（2）从减小问题规模的角度,对大部分问题而言比例列的预处理效果优于优先列。     

Audit committee perspectives on mandatory audit firm rotation: evidence from Canada

This study examines audit committee (AC) members’ perspectives on mandatory audit firm rotation (MAFR), mandatory audit partner rotation, ways in which ACs monitor auditor independence and objectivity, and the costs associated with switching audit firms. In-person interviews with AC members in Canada were conducted to improve our understanding of the reasons underlying AC members’ positions on MAFR. All AC members interviewed in this study were adamantly opposed to MAFR. MAFR was perceived as a threat to their shareholder-granted authority to make audit firm appointment decisions. Participants believe that their professional judgment and observations are the most effective means of ensuring auditor independence and view MAFR as an unnecessary intervention. We explain these results using self-determination theory. Our findings were also used to develop a conceptual model of AC relationships with external auditors and financial management.     

Dual-class shares,external financing needs,and firm performance

Whereas the agency theory predicts that dual-class shares decrease firm performance, the stewardship theory predicts that dual-class shares increase firm performance. The cumulative findings on the performance consequences of dual-class shares have been weak and/or inconclusive. Because endogeneity is a constant challenge in empirical corporate governance studies, this study uses a unique law change in Switzerland as a source of exogenous variation in the fraction of firms with dual-class shares. Controlling for firm fixed effects and time-varying confounders, we find that dual-class shares neither harm nor benefit firm performance on average. However, dual-class shares increase firm performance if the firm requires external finance and dual-class shares decrease firm performance if the firm does not require external finance. External financing needs mitigate the agency costs between controlling and minority shareholders and create a context in which dual-class shares facilitate firm-specific investments instead of private perquisites. The study’s results have both managerial and policy implications.     

Estimation of parameters of a right truncated exponential distribution

The maximum likelihood, moment and mixture of the estimators are for samples from the right truncated exponential distribution. The estimators are compared empirically when all the parameters are unknown; their bias and mean square error are investigated with the help of numerical technique. We have shown that these estimators are asymptotically unbiased. At the end, we conclude that mixture estimators are better than the maximum likelihood and moment estimators.     

Minimum phi-divergence estimators for loglinear models with linear constraints and multinomial sampling

In this paper the family ofφ-divergence estimators for loglinear models with linear constraints and multinomial sampling is studied. This family is an extension of the maximum likelihood estimator studied by Haber and Brown (1986). A simulation study is presented and some alternative estimators to the maximum likelihood are obtained. This work was parcially supported by Grant DGES PB2003-892     

Berry–Esseen type bounds for trimmed U-statistics

Trimmed U  -statistics can be constructed in two different ways: by basing the statistic on a trimmed sample or by averaging the trimmed set of kernel values. Mild conditions are given to ensure the rate of convergence to normality is O(n^-1/2)$\mathrm{O}(n^{-1/2})$ in both cases.