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971.
972.
Twitter data has recently been considered to perform a large variety of advanced analysis. Analysis of Twitter data imposes new challenges because the data distribution is intrinsically sparse, due to a large number of messages post every day by using a wide vocabulary. Aimed at addressing this issue, generalized itemsets – sets of items at different abstraction levels – can be effectively mined and used to discover interesting multiple-level correlations among data supplied with taxonomies. Each generalized itemset is characterized by a correlation type (positive, negative, or null) according to the strength of the correlation among its items.This paper presents a novel data mining approach to supporting different and interesting targeted analysis – topic trend analysis, context-aware service profiling – by analyzing Twitter posts. We aim at discovering contrasting situations by means of generalized itemsets. Specifically, we focus on comparing itemsets discovered at different abstraction levels and we select large subsets of specific (descendant) itemsets that show correlation type changes with respect to their common ancestor. To this aim, a novel kind of pattern, namely the Strong Flipping Generalized Itemset (SFGI), is extracted from Twitter messages and contextual information supplied with taxonomy hierarchies. Each SFGI consists of a frequent generalized itemset X and the set of its descendants showing a correlation type change with respect to X.Experiments performed on both real and synthetic datasets demonstrate the effectiveness of the proposed approach in discovering interesting and hidden knowledge from Twitter data. 相似文献
973.
Internally heat-integrated distillation column (HIDiC) is the most radical approach of a heat pump design, making efficient use of internal heat-integration: the rectifying section of a distillation column operating at a higher pressure becomes the heat source, while the stripping part of the column acts as a heat sink. Remarkably, a HIDIC can bring up to 70% energy savings compared to conventional distillation columns. This is highly appealing regarding the fact that distillation is one of the most energy intensive operations in the chemical process industry accounting for over 40% of the energy usage. This review paper describes the latest developments concerning this promising but difficult to implement process intensification technology, covering all the major aspects related to the working principle, thermodynamic analysis, potential energy savings, various design configurations and construction options (ranging from inter-coupled or concentric columns, shell and tube and plate–fin heat exchanger columns to SuperHIDiC), design optimization, process control and operation issues, as well as pilot-scale and potential industrial applications. Further advancement, i.e., development of HIDiC technology for multi-component mixture separations is an extremely challenging research topic, especially when HIDiC becomes associated with other technologies such as dividing-wall column (DWC) or reactive distillation (RD). 相似文献
974.
结合工程项目资料整理经验,从工作态度、职责、专业知识等方面就如何做好工程项目资料整理工作进行了论述,并总结出资料整理过程中需要注意的问题,对实际工程具有一定参考意义。 相似文献
975.
Costin S Bîldea Cătălin Pătruţ Sten Bay Jørgensen Jens Abildskov Anton A Kiss 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2016,91(5):1215-1223
Process intensification in distillation systems has received much attention during past decades, with the aim of increasing both energy and separation efficiency. Various techniques, such as internal heat‐integrated distillation, membrane distillation, rotating packed bed, dividing‐wall columns and reactive distillation were studied and reported in the literature. All these techniques employ the conventional continuous counter‐current contact of vapor and liquid phases. Cyclic distillation technology is based on an alternative operating mode using separate phase movement which leads to key practical advantages in both chemical and biochemical processes. This article provides a mini‐review of cyclic distillation technology. The topics covered include the working principle, design and control methods, main benefits and limitations as well as current industrial applications. Cyclic distillation can be rather easily implemented in existing columns by simply changing the internals and the operating mode, thus bringing new life to old distillation towers by significantly increasing the column throughput, reducing the energy requirements and offering better separation performance. © 2016 Society of Chemical Industry 相似文献
976.
Within the enterprise important conversations are shifting to Social Media Microblogs thus providing a new source for the acquisition of tacit knowledge useful for intelligent agents. While automated retrieval of candidate experts from Web documents has been well-researched, little exists that leverages social aspects of Microblogs for this purpose. We show that the experts and their related expertise can also be identified in the enterprise corpus. Analysis reveals the existence of problem-solving threads where the requestor seeking help often elicits responses from experts which consequently records tacit (experiential) knowledge. Here we present rules to automate the acquisition of this tacit knowledge. The rules are based on probabilistic models enhanced with linguistics to exploit the role patterns in threads. Heuristics also strengthen local evidence about associations between candidates, documents and (expertise) terms. Applying this, we demonstrate that the Enhanced Models can ameliorate the negative impact of Microblogs (such as sparse data, short content, and implicit associations). The experiments show that the candidate models significantly outperform the document models in the Microblog environment. This is different from previous research in Web environments. Examples also illustrate underlying insights and emphasize the ‘additive’ nature of expertise found in Social Media. 相似文献
977.
Anton A. Kiss 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2014,89(4):479-498
Throughout history, distillation has been the most widespread separation method. However, despite its simplicity and flexibility, distillation still remains very energy inefficient. Novel distillation concepts based on process intensification, can deliver major benefits, not just in terms of significantly lower energy use, but also in reducing capital investment and improving eco‐efficiency. While very likely to remain the separation technology of choice for the next decades, there is no doubt that distillation technology needs to make radical changes in order to meet the demands of the energy‐conscious modern society. This article aims to show that in spite of its long age, distillation technology is still young and full of breakthrough opportunities. Moreover, it provides a broad overview of the recent developments in distillation based on process intensification principles, for example heat pump assisted distillation (e.g. vapor compression or compression–resorption), heat‐integrated distillation column, membrane distillation, HiGee distillation, cyclic distillation, thermally coupled distillation systems (Petlyuk), dividing‐wall column, and reactive distillation. These developments as well as the future perspectives of distillation are discussed in the context of changes towards a more energy efficient and sustainable chemical process industry. Several key examples are also included to illustrate the astonishing potential of these new distillation concepts to significantly reduce the capital and operating cost at industrial scale. © 2013 Society of Chemical Industry 相似文献
978.
本文从视觉知识的角度出发,论述了全球文化资本价值输出语境下的大学当代艺术文化教育及其方法研究的意义。视觉知识作为大学当代艺术文化教育和当代艺术设计教育的学科基础,旨在结合现代语言学、符号学、社会学方法,深化研究当代艺术和当代设计与自然、社会之间的复杂关系,从方法论意义上推进大学当代艺术文化教育方法研究。 相似文献
979.
980.
This is the first study that uses multilevel modelling to analyse regional influence on the decision to invest in innovation activities of firms in a single developing country, Ecuador. Our results indicate that the decision to invest in R&D and in other innovation activities are conditioned by the region in which the firm is located. Regional loan volume, orientation towards knowledge exploitation and intra-regional-sectorial R&D spillovers are positively associated with both types of innovation activities, while regional levels of co-operation and inter-regional R&D spillovers are only positively associated with the probability of investing in other innovation activities. 相似文献