数据仓库中的元数据

数据是数据仓库的基础,而元数据和访问元数据的工具决定着用户利用数据仓库中数据的能力。本文研究了元数据的收集、维护和配备,简要介绍了其与数据访问工具集成的几个层次。     

建筑信息模型(BIM)在海洋工程结构设计中的应用研究

根据目前我国海洋工程领域的信息化现状,提出在设计、施工、运营维护阶段应用BIM技术(建筑信息模型)实施BLM系统(建筑工程生命周期管理)的构想,从而更快地提高企业核心竞争力。并针对海洋油气开发的特点和结构设计阶段的问题,提出了由Revit(前处理)到SACS(结构设计计算),再到Revit(后处理)的BIM技术具体实施方法,采用该方法可为企业带来巨大的经济效益,并为后期的施工、运营维护阶段应用BIM技术定下了基调。     

基于BIM技术的建设工程生命周期管理研究

在分析建筑业低效率原因的基础上, 提出效率提高的重点是实现建设项目全生命周期信息集成化管理。论文对BLM思想的形成、发展、内涵进行论述后,指出BLM实施的关键技术在于BIM, 并从建设项目全寿命周期的角度对BIM技术的概念、产品、应用进行了较为深入的研究,并指出BIM在我国推广应用中的存在的问题和解决路径,期望能引起更多的人关注BIM技术,并为BIM技术在我国的研究和实践提供参考。     

Environmental and economic assessment of producing hydroprocessed jet and diesel fuel from waste oils and tallow

Animal fats and waste oils are potential feedstocks for producing hydroprocessed esters and fatty acids (HEFA) jet and diesel fuels. This paper calculates the lifecycle greenhouse gas (GHG) emissions and production costs associated with HEFA jet and diesel fuels from tallow, and from yellow grease (YG) derived from used cooking oil. For YG, total CO₂ equivalent (CO₂ eq.) GHG emissions of jet and diesel were found to range between 16.8–21.4 g MJ⁻¹ and 12.2–16.9 g MJ⁻¹ respectively. This corresponds to lifecycle GHG emission reductions of 76–81% and 81–86% respectively, compared to their conventional counterparts. Two different system boundaries were considered for tallow-derived HEFA fuels. In System 1 (S1), tallow was treated as a by-product of the rendering industry, and emissions from rendering and fuel production were included. In System 2 (S2), tallow was considered as a by-product of the meat production industry, and in addition to the S1 emissions, cattle husbandry and slaughtering were also included. The lifecycle emissions (CO₂ eq.) from HEFA jet fuel for S1 and S2 were estimated to be 25.7–37.5 g MJ⁻¹ and 67.1–83.9 g MJ⁻¹ respectively. HEFA diesel lifecycle emissions were found to be 21.3–33.3 g MJ⁻¹ for S1 and 63.4–80.5 g MJ⁻¹ for S2. Production costs for these fuels were calculated using a discounted cash flow rate of return model. The minimum selling price was estimated to be 880 $ m⁻³–1060 $ m⁻³ for YG-derived HEFA, and 1050–1250 $ m⁻³ for tallow-derived HEFA fuels.     

Condition-based Maintenance and the product improvement process

The evolution of enterprise services is changing the approach for enabling Product Lifecycle Management (PLM) and Supply Chain Management (SCM) business processes. Enabling systems are migrating to process- and service-oriented solutions. In particular, the paper demonstrates how the new technologies can be used to enable a critical process that links vehicle health maintenance to PLM. Our hypothesis is that Condition-based Maintenance (CBM) and PLM integration is achievable through composite application design. The key process for linking CBM to PLM must convert prognostic and diagnostic information into actionable information that can be directed into a project-level PLM environment that supports the end-to-end product improvement process. To test this hypothesis, we designed a composite application within the context of a Small Business Innovative Research project that is sponsored by the US government. This paper motivates the problem from the strategic level to the implementation level and describes the successful test of the hypothesis.     

一个用于取得符合IEC 61508组织性功能安全认证的方法论——第三部分：安全生命周期和功能安全管理系统的开发

IEC 61508和IEC 61511为那些涉及在危险的与安全相关的环境下运营,同时想证明自身在功能安全管理方面有合规能力和资质的企业设立了一个全球通用的标准。本文是功能安全手册的第三部分,它介绍了系统集成商采用的安全生命周期模型的详细内容。该功能安全模型对应于IEC 61508的第9阶段和IEC 61511的第4阶段中的逻辑解算器子系统。本文描述了安全生命周期中的关键流程和应交付的内容,以及安全生命周期项目的关键活动和功能安全评估-后者的活动通常不易为人理解,或为安全团体所使用,但它们在确保达到功能安全时是必不可少的。     

Optimization of Steel Production to Improve Lifecycle Environmental Performance

To reduce lifecycle impacts, manufacturers require an understanding of how design, manufacturing, and other decisions influence their eco-footprint across all product lifecycle stages, e.g., manufacturing, use, and end-of-life. However, few tools exist to address manufacturing impacts on the environment. For many products, steelmaking accounts for the majority of manufacturing energy use, with process wastes also representing significant concerns. A predictive model for a steelmaking electric arc furnace (EAF) is briefly described and is then used to illustrate how environmental performance can be optimized for a given steel alloy. Process inputs are identified that minimize a variety of environmental measures.     

Lifecycle assessment of the economic, environmental and energy performance of Jatropha curcas L. biodiesel in China

Due to issues relating to the sustainability of biofuel production, second generation biofuel has attracted much attention. As a promising feedstock of second generation biodiesel, Jatropha curcas L. (JCL) is being massively planted on marginal land in China, but its viability as a biofuel source has not been systematically assessed. This paper performed a lifecycle assessment of the economic, environmental and energy (3E) performance of the JCL biodiesel, assuming JCL oil is either used for direct blending with diesel or further processed into JCL methyl ester (JME). The results show that, at the current technical levels, the production of JCL biodiesel is financially infeasible, but has positive environmental and energy performance. Despite the additional cost incurred in the transesterification process, the net present value of JME is slightly higher than that of JCL oil when a part of the cost is allocated to the co-product, i.e., glycerin. As compared with that of diesel, the production and consumption of per liter JCL oil and JME can reduce 7.34 kg and 8.04 kg CO₂ equivalent, respectively. The energy balances of both JCL oil and JME are 1.57 and 1.47, respectively, in terms of the ratio of the heat value of biodiesel and that of energy input. The main factors affecting the 3E performance of JCL biodiesel are seed yield, co-product output, and farm energy input.     

Valuing the greenhouse gas emissions from nuclear power: A critical survey

This article screens 103 lifecycle studies of greenhouse gas-equivalent emissions for nuclear power plants to identify a subset of the most current, original, and transparent studies.     

Strategic decision-making method for eco-business planning

Due to growing concerns about environmental problems, product life cycle design that aims to maximize total value while minimizing environmental load and costs should be implemented. To do so, the processes of idea generation and decision-making for eco-business strategies, as well as the design of a target product, should be systematically supported. This paper proposes a strategic decision-making method for eco-business planning that allows a designer to easily find a set of eco-business ideas that effectively improves environmental and economic performance simultaneously. A decision-making procedure based on this method is illustrated with a simplified example of a laptop computer business.