石油价格波动对中国城乡居民消费水平的差异性影响研究     

丁志华  李文博  何凌云  刘振华 《资源科学》2014,36(12):2540-2548

石油价格波动对我国城乡居民消费水平的变化有重要影响。基于计量经济模型和时变状态空间模型,采用我国2000年6月-2014年5月的时间序列数据,就石油价格波动对我国城乡居民消费水平的长短期影响效力、影响时滞和动态时变效率进行了分析。研究结果表明:在长期和短期内,石油价格波动对我国城乡居民消费水平均造成正向影响,且对城镇居民消费水平的影响效力更为显著;石油价格波动对城乡居民消费水平的平均影响时滞分别为5个月和4个月;城乡居民消费水平对石油价格变动的时变弹性起伏较大,且城镇居民消费水平对石油价格变动的时变弹性在总体上要大于农村居民消费水平对石油价格变动的时变弹性。并就上述研究结论,从调整石油定价机制、建立健全预警机制和加强对居民的政策扶持等三个方面提出了政策建议。  相似文献   

国内开放存取领域的研究热点和作者合作团体透析——基于共现分析和社会网络分析     

徐迎迎  魏瑞斌  张文琴 《现代情报》2014,34(8):112-118

文章以中国期刊全文数据库（CNKI）为数据源,以发表在CSSCI和核心期刊的2004-2013年有关开放存取的507篇文献为研究对象,对其进行年代分析,研究发现：2004-2008年开放存取研究呈现迅猛增长趋势,2009-2013年开放存取的研究趋势平稳,因此文章将开放存取的发展分为2个阶段,即开放存取研究的第一个阶段（2004-2008年）、开放存取研究的第二个阶段（2009-2013年）。利用关键词共现分析方法分析我国开放存取在每个阶段的研究热点,并采用社会网络分析方法分析开放存取文献的高产作者,以透析国内开放存取领域的研究热点和作者合作团体,从多方面揭示国内开放存取的发展现状和研究趋势。  相似文献   

基于Web挖掘的突发事件网络舆情预警研究     

董坚峰 《现代情报》2014,34(2):43-47,51

当前网络突发事件频发,网络舆情与突发事件的相互作用增加了舆情分析和预警的难度,现有舆情预警系统无法满足需求。将Web挖掘技术引入到突发事件网络舆情预警中,构建了包括舆情采集层、舆情挖掘层、舆情分析层、预警研判层的基于Web挖掘的突发事件网络舆情预警系统模型,集成和整合了突发事件网络舆情预警全过程的重要功能,实现突发事件网络舆情采集、分析处理、危机预警的自动化、智能化和实时化。  相似文献   

Optimal linear attack for multi-sensor network against state estimation     

《Journal of The Franklin Institute》2022,359(16):9220-9240

This paper is concerned with a security problem about malicious integrity attacks in state estimation system, in which multiple smart sensors locally measure information and transmit it to a remote fusion estimator though wireless channels. A joint constraint is considered for the attacker behaviour in each channel to keep stealthiness under a residual-based detector on the remote side. In order to degrade the estimator performance, the attacker will maximize the trace of the remote state estimation error covariance which is derived based on Kalman filter theory. It is proved that the optimal linear attack strategy design problem is convex and finally turned into a semi-definite programming problem. In addition, the tendency of attack behaviour on recursive and fixed Kalman filter system is analyzed. Several examples are given to illustrate the theoretical results.  相似文献   

Practical stability of impulsive stochastic delayed systems driven by G-Brownian motion     

《Journal of The Franklin Institute》2022,359(8):3749-3767

This paper investigates practical stability problem for nonlinear impulsive stochastic delayed systems driven by G-Brownian motion (IGSDSs). Practical stability can describe quantitative properties and qualitative behavior in contrast to traditional Lyapunov stability theory. Based on G-Lyapunov function, Razumikhin-type theorem, G-Itô formula, Burkholder–Davis–Gundy (B-D-G) inequalities I & II and stochastic analysis technique, some new criteria for moment and quasi sure global practical uniform exponential stability of IGSDSs are proposed. Finally, two examples are presented to verify validity of our theoretical results.  相似文献   

Franklin Institute Awards Call for Nominations     

《Journal of The Franklin Institute》2022,359(6):iv

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Provider fairness across continents in collaborative recommender systems     

《Information processing & management》2022,59(1):102719

When a recommender system suggests items to the end-users, it gives a certain exposure to the providers behind the recommended items. Indeed, the system offers a possibility to the items of those providers of being reached and consumed by the end-users. Hence, according to how recommendation lists are shaped, the experience of under-recommended providers in online platforms can be affected. To study this phenomenon, we focus on movie and book recommendation and enrich two datasets with the continent of production of an item. We use this data to characterize imbalances in the distribution of the user–item observations and regarding where items are produced (geographic imbalance). To assess if recommender systems generate a disparate impact and (dis)advantage a group, we divide items into groups, based on their continent of production, and characterize how represented is each group in the data. Then, we run state-of-the-art recommender systems and measure the visibility and exposure given to each group. We observe disparities that favor the most represented groups. We overcome these phenomena by introducing equity with a re-ranking approach that regulates the share of recommendations given to the items produced in a continent (visibility) and the positions in which items are ranked in the recommendation list (exposure), with a negligible loss in effectiveness, thus controlling fairness of providers coming from different continents. A comparison with the state of the art shows that our approach can provide more equity for providers, both in terms of visibility and of exposure.  相似文献   

Users’ ability to perceive misinformation: An information quality assessment approach     

《Information processing & management》2022,59(1):102739

Digital information exchange enables quick creation and sharing of information and thus changes existing habits. Social media is becoming the main source of news for end-users replacing traditional media. This also enables the proliferation of fake news, which misinforms readers and is used to serve the interests of the creators. As a result, automated fake news detection systems are attracting attention. However, automatic fake news detection presents a major challenge; content evaluation is increasingly becoming the responsibility of the end-user. Thus, in the present study we used information quality (IQ) as an instrument to investigate how users can detect fake news. Specifically, we examined how users perceive fake news in the form of shorter paragraphs on individual IQ dimensions. We also investigated which user characteristics might affect fake news detection. We performed an empirical study with 1123 users, who evaluated randomly generated stories with statements of various level of correctness by individual IQ dimensions. The results reveal that IQ can be used as a tool for fake news detection. Our findings show that (1) domain knowledge has a positive impact on fake news detection; (2) education in combination with domain knowledge improves fake news detection; and (3) personality trait conscientiousness contributes significantly to fake news detection in all dimensions.  相似文献   

A hierarchical network-oriented analysis of user participation in misinformation spread on WhatsApp     

《Information processing & management》2022,59(1):102757

WhatsApp emerged as a major communication platform in many countries in the recent years. Despite offering only one-to-one and small group conversations, WhatsApp has been shown to enable the formation of a rich underlying network, crossing the boundaries of existing groups, and with structural properties that favor information dissemination at large. Indeed, WhatsApp has reportedly been used as a forum of misinformation campaigns with significant social, political and economic consequences in several countries.In this article, we aim at complementing recent studies on misinformation spread on WhatsApp, mostly focused on content properties and propagation dynamics, by looking into the network that connects users sharing the same piece of content. Specifically, we present a hierarchical network-oriented characterization of the users engaged in misinformation spread by focusing on three perspectives: individuals, WhatsApp groups and user communities, i.e., groupings of users who, intentionally or not, share the same content disproportionately often. By analyzing sharing and network topological properties, our study offers valuable insights into how WhatsApp users leverage the underlying network connecting different groups to gain large reach in the spread of misinformation in the platform.  相似文献   

What a firm produces matters: Processes of diversification,coherence and performances of Indian manufacturing firms     

《Research Policy》2022,51(8):104152

Economic growth and development of a country involves the accumulation of knowledge and dynamic capabilities. Past research has begun to investigate capability accumulation and macro-economic development of countries and sectors, and the role of new products in these processes. In this work, we focus on the firm-level process of capability accumulation and diversification in a developing country, namely, India. First, we explore the drivers of firm diversification strategies, and the effects of diversification upon firm performance in terms of profitability and sales growth. Second, we look at the idiosyncratic characteristics of different products, trying to identify the synergies of a product line with respect to the overall product basket of the firm – i.e. the “coherence” of its diversification patterns. We observe that the future performance of firms crucially depends on the interactions between the products they produce.  相似文献