Bayesian selection of technology assumptions for the transformation from supply-use to input–output tables

ABSTRACT

In the construction of input–output models from supply-use tables, technology assumptions disambiguate how an industry uses inputs in the production recipe of multiple outputs. This paper uses Bayes' theorem to select technology assumptions, taking into account empirical observations. The paper presents a formulation to explore hybrids between product and industry technology assumptions in product-by-product tables. We then present Markov chain Monte-Carlo techniques to implement the Bayesian method for selecting technology assumptions. We apply the method in a case study using Eurostat supply-use tables of 2004 and 2005, exhibiting a volume of secondary products of less than 13%, and 59 products and industries per country. The results show that the choice of technology is not important, given that there is no strong evidence in favour of any of them.     

Fuel consumption for various driving styles in conventional and hybrid electric vehicles: Integrating driving cycle predictions with fuel consumption optimization*

Improving fuel economy and lowering emissions are key societal goals. Standard driving cycles, pre-designed by the US Environmental Protection Agency (EPA), have long been used to estimate vehicle fuel economy in laboratory-controlled conditions. They have also been used to test and tune different energy management strategies for hybrid electric vehicles (HEVs). This paper aims to estimate fuel consumption for a conventional vehicle and a HEV using personalized driving cycles extracted from real-world data to study the effects of different driving styles and vehicle types on fuel consumption when compared to the estimates based on standard driving cycles. To do this, we extracted driving cycles for conventional vehicles and HEVs from a large-scale U.S. survey that contains real-world GPS-based driving records. Next, the driving cycles were assigned to one of three categories: volatile, normal, or calm. Then, the driving cycles were used along with a driver-vehicle simulation that captures driver decisions (vehicle speed during a trip), powertrain, and vehicle dynamics to estimate fuel consumption for conventional vehicles and HEVs with power-split powertrain. To further optimize fuel consumption for HEVs, the Equivalent Consumption Minimization Strategy (ECMS) is applied. The results show that depending on the driving style and the driving scenario, conventional vehicle fuel consumption can vary widely compared with standard EPA driving cycles. Specifically, conventional vehicle fuel consumption was 13% lower in calm urban driving, but almost 34% higher for volatile highway driving compared with standard EPA driving cycles. Interestingly, when a driving cycle is predicted based on the application of case-based reasoning and used to tune the power distribution in a hybrid electric vehicle, its fuel consumption can be reduced by up to 12% in urban driving. Implications and limitations of the findings are discussed.     

多孔连续斜交框架桥顶进施工过程受力分析

城市道路下穿铁路框架桥顶进施工的关键是合理控制桥梁主体结构的受力。为了对框架桥顶进施工过程进行受力特性分析，采用Midas有限元软件模拟了框架桥在滑板上开始顶进、框架桥重心即将离开滑板、框架桥顶进即将就位三个施工阶段。结果表明，该框架桥的施工过程是安全可靠的，同时结合工程项目实际给出了顶进施工的注意事项。该方法可用来指导类似工程顶进施工过程的受力分析和施工控制。     

桥梁路面防水施工技术关键点研究

桥梁工程具有周期长以及范围大等特点。因此,在桥梁施工中任何一个环节出现偏差,都可能诱发裂缝或剥离等问题,最终影响整个桥梁的质量。路面防水工程是桥梁施工项目中的重要环节,防水工程的施工质量将直接影响桥梁结构的整体质量以及使用寿命。因此,在桥梁防水施工过程中,要选择合格的施工材料以及最优的施工方法,从而提高桥梁路面防水工程的施工质量。     

混合型基金绩效评估及驱动因素分析——基于DEA-Tobit模型

将随机选出的混合型基金作为研究样本,采用DEA-Tobit二阶段模型进行研究.首先利用数据包络模型对样本进行绩效评估,在此基础上,利用Tobit模型研究相关指标对于基金绩效的影响机制.结果表明,基金本身所面临的风险收益因素以及基金经理团队稳定性对于基金绩效均具显著影响.最后结合实证结果就提升中国基金绩效提出相关的建议.     

基于两阶段法的多车型卷烟配送路径优化研究

在烟草商业企业中,物流是其重要的环节,是连接客户与烟草企业间的纽带,其卷烟配送线路设计的合理与否直接影响到卷烟的配送效率和配送成本,就如何合理的规划线路成为卷烟配送的关键问题。文章以Q烟草公司为例,运用先分组后路线的两阶段法对问题进行求解,先利用K-means聚类算法对区域进行划分,再考虑工作量均衡的条件下引入遗传算法对区域进一步调整,最后利用混合遗传算法对各配送区域进行线路优化,通过实例从线路数、车辆数、空载率、配送里程及总成本等指标上可以看出两阶段法的配送效果更优。     

一般竞争战略理论论战、观点流派与研究展望——从割裂到融合

一般竞争战略理论对企业战略决策具有广泛而深远的影响。学者们对一般竞争战略的割裂观和融合观一直争执不休，众多研究呈现出多角度、多证据、结论矛盾和研究混乱的局面。文章通过对相关理论回顾和梳理，揭示出一般竞争战略理论割裂观存在的问题和困境，呈现融合观的理论与实证证据，提炼出混合战略的三个流派，并揭示混合战略研究的脉络和趋势。文章揭示出融合是竞争战略的趋势，实现不同战略类型的融合和竞争战略的多维体系构建，有助于厘清竞争战略研究的混乱和矛盾，打破根深蒂固的“骑墙战略”禁区思维，为企业的战略决策提供系统和多维的视角，并推动一般竞争战略从割裂化向融合化演进，特别是对现阶段的中国企业战略制定具有重要意义。     

阐述如何加强道路桥梁施工监理

通常,道路桥梁的施工难度较高,其中涵盖的内容较多,如技术管理、预算管理、成本控制等。这些因素使道路桥梁的施工变得更为困难,施工的复杂性和综合性更加突出。在桥梁的施工过程中,存在着许多风险,所以需要做好施工监理工作,从而最大限度地保障施工过程中不会出现任何故障和问题。因此,加强道路桥梁施工监理至关重要。论文从道路桥梁施工的角度,探究和分析如何做好相关的监理工作。     

Digital Platforms and the Nature of the Firm

Abstract:

Digital platforms turn traditional approaches of the firm, which relied on the wage relation to explain the major difference between firm and market, upside down and underline the advantages of coordination through organization over coordination through market. This study aims to propose a definition of the firm able to integrate, besides the integrated firm, also hybrid forms such as networks of subcontractor/subcontracting firms as well as atypical forms such as digital platforms. By reactivating the firm-boundary problem, this article suggests putting valorization by labor at the heart of the firm’s decisions concerning integration. It suggests therefore a general definition of the firm as a techno-institutional center of capital valorization, provided that firms make profits by means of the appropriation of labor incorporated into their (productive, structural, intellectual) capital through institutional arrangements. By stressing the relation of production between the owners of the means of production and the direct producers, the approach of the firm supported here should allow to cover the different existing models of the firm, from the classical firm to hybrid models, around which the boundary debate has revolved, to digital platforms.     

大吨位宽幅转体现浇箱梁支架设计与施工

桥梁水平转体施工技术日趋成熟,大跨度、大吨位等技术指标不断突破,转体法施工优势得到充分发挥。本文根据桥梁分段现浇、一次整体转体到位的特点,结合转体法施工工况,论述了软弱地基条件下大吨位宽幅转体现浇梁支架设计与施工技术。