Closing the loop: Empirical evidence for a positive feedback model of IT business value creation

Researchers have established that information technology (IT) can improve firms’ productivity. Whether improved productivity leads to additional investment in IT, however, remains largely uninvestigated. In this paper, we consider whether the relationship between productivity and subsequent IT investment might be positive, negative, or ad hoc, and hypothesize that this relationship is positive. We analyze seven years of panel data from 1236 healthcare firms and present empirical evidence supporting our hypothesis. When our finding is combined with extant research, it becomes reasonable to propose that unidirectional causality does not fully describe the process of IT business value creation. Instead, we argue that existing static models of IT business value with unidirectional causality can be recast as dynamic models that explicitly incorporate multiple time periods and a positive feedback relationship to more accurately capture the complexity of this process. The creation of IT business value can thus be understood as a positive feedback model where IT investment in a given time period builds the stock of IT inputs, where those IT inputs then impact productivity, and where productivity leads to IT investment in a future time period, beginning the cycle anew.     

沪深股市权证和股票的互动关系研究

以向量误差修正模型为基础,结合格兰杰因果关系检验,对当前我国沪深股市中权证及其标的股票的互动关系进行了实证研究.在分别对1 min价格行为和5 min价格行为进行了检验、对比和综合之后发现:1 min数据中,权证和标的股票间存在显著的反馈关系,但权证对股票的影响相对更持久,权证对股票存在弱领先效应;5 min数据中,二者间基本不存在反馈效应,股票对权证几乎没有影响,而权证对股票存在强领先效应.综合两组数据的结果,有充分证据表明权证和标的股票间存在引导/滞后及反馈关系,且总体上说,权证的价格变化处于领先地位.     

Bounds test approach to cointegration and causality between nuclear energy consumption and economic growth in India

This paper attempts to examine the dynamic relationship between economic growth, nuclear energy consumption, labor and capital for India for the period 1969–2006. Applying the bounds test approach to cointegration developed by Pesaran et al. (2001) we find that there was a short- and a long-run relationship between nuclear energy consumption and economic growth. Using four long-run estimators we also found that nuclear energy consumption has a positive and a statistically significant impact on India's economic growth. Further, applying the Toda and Yamamoto (1995) approach to Granger causality and the variance decomposition approach developed by Pesaran and Shin (1998), we found a positive and a significant uni-directional causality running from nuclear energy consumption to economic growth without feedback. This implies that economic growth in India is dependent on nuclear energy consumption where a decrease in nuclear energy consumption may lead to a decrease in real income. For a fast growing energy-dependent economy this may have far-reaching implications for economic growth. India's economic growth can be frustrated if energy conservation measures are undertaken without due regard to the negative impact they have on economic growth.     

Examining carbon emissions economic growth nexus for India: A multivariate cointegration approach

The study probes cointegration and causality between carbon emissions and economic growth for India using ARDL bounds testing approach complemented by Johansen–Juselius maximum likelihood procedure in a multivariate framework by incorporating energy supply, investment and employment for time span 1971–2006. The study fails to establish long-run equilibrium relationship and long term causality between carbon emissions and economic growth; however, there exists a bi-directional short-run causality between the two. Hence, in the short-run, any effort to reduce carbon emissions could lead to a fall in the national income. This study also establishes unidirectional short-run causality running from economic growth to energy supply and energy supply to carbon emissions. The absence of causality running from energy supply to economic growth implies that in India, energy conservation and energy efficiency measures can be implemented to minimize the wastage of energy across value chain. Such measures would narrow energy demand–supply gap. Absence of long-run causality between carbon emissions and economic growth implies that in the long-run, focus should be given on harnessing energy from clean sources to curb carbon emissions, which would not affect the country’s economic growth.     

The role of inertia in explanations of project performance: A framework and evidence from project-based organizations

The paper argues that inertia governs the search for explanations of project performance in ways that potentially could impair the quality of feedback obtained about past performance, and thus jeopardise ongoing strategy-making. Based on a critique of relevant literature, the paper presents a novel three-stage framework for analysing connections among inertia and the search for explanations of performance in project-based organizations. This framework helps to show the significance of inertia for the adoption of alternative routes for such search. The framework is illustrated using case study vignettes. These are based on in-depth interviews with senior project management practitioners at two global organizations, about the explanation of project performance (i.e. the attainment or failure to achieve related objectives). Conjectures based on the framework and the vignettes are presented to stimulate further research on how organizations search for explanations of project performance, and on the implications of inertia for organizational and project level learning and strategy.     

故障树向因果图转换的研究

故障树和因果图都采用图形表示因果关系,都主要用于故障诊断和故障分析。由于二者的相似点较多,因此研究故障树向因果图的转换显得十分重要。这样可以进一步扩大因果图的应用范围。文章在分析故障树与因果图概念和表示符号的基础上,探讨了故障树与因果图之间的相互转换,提出了故障树转换为因果图的方法。研究结果表明：含有“与门”、“或门”、“禁门”和“表决门”的故障树可以转换为因果图,这样对于这类故障树处理的故障诊断问题都可以采用因果图来解决。     

Growth and oil price: A study of causal relationships in small Pacific Island countries

This paper investigates the nexus between economic growth and oil price in small Pacific Island countries (PICs). Except Papua New Guinea, none of the 14 PICs has fossil any fuel resources. Consequently, the other 13 PICs are totally dependent on oil imports for their economic activities. Since PICs have limited foreign exchange earning capacities, as they have a very narrow range of exports and are highly dependent on foreign aid, high oil prices in recent months have seriously tested their economic resilience. This paper applies the ARDL bounds testing methodology to four selected PICs, Samoa, Solomon Islands, Tonga and Vanuatu, which have consistent and reliable time series of data, with a view to assess the impact of oil price on economic growth. The findings are that oil price, gross domestic product and international reserve are cointegrated in all the four PICs. Further, both in the long and short runs, we observe that there is a uni-directional relationship as causality linkage runs only from oil price and international reserves to economic growth. The paper makes some policy recommendations.     

融合对抗学习的因果关系抽取

因果关系抽取在事件预测、情景生成、问答以及文本蕴涵等任务上都有重要的应用价值.但多数现有的因果关系抽取方法都需要人工定义模式和约束,且严重依赖知识库.为此,本文利用生成式对抗网络（Generative adversarial networks,GAN）的对抗学习特性,将带注意力机制的双向门控循环单元神经网络（Bidirectional gated recurrent units networks,BGRU）与对抗学习相融合,通过重定义生成模型和判别模型,基本的因果关系抽取网络能够与判别网络形成对抗,进而从因果关系解释信息中获得高区分度的特征.实验结果表明,与当前用于因果关系抽取的方法相比较,该方法表现出更优的抽取效果.     

Vector time and causality among abstract events in distributed computations

An important problem in analyzing distributed computations is the amount of information. In event-based models, even for simple applications, the number of events is large and the causal structure is complex. Event abstraction can be used to reduce the apparent complexity of a distributed computation. This paper discusses one important aspect of event abstraction: causality among abstract events. Following Lamport [24], two causality relations are defined on abstract events, called weak and strong precedence. A general theoretical framework based on logical vector time is developed in which several meaningful timestamps for abstract events are derived. These timestamps can be used to efficiently determine causal relationships between arbitrary abstract events. The class of convex abstract events is identified as a subclass of abstract events that is general enough to be widely applicable and restricted enough to simplify timestamping schemes used for characterizing weak precedence. We explain why such a simplification seems not possible for strong precedence. Received: February 1994 / Accepted: July 1997