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.     

基于抽样的因果图仿真推理算法研究

由于因果图的经典推理的计算复杂度是NP难的,因此其不便于推广和使用。基于因果图理论和MonteCarlo思想,提出了基于抽样的A-R Sampling和重要性抽样的因果图仿真推理算法。在故障诊断中的有效应用验证了方法是可行的。     

连续因果图的推理及参数学习

因果图理论是利用图形化和直接因果强度来表达知识和因果关系的一种基于概率论的推理方法,而对于连续的因果图连接事件的概率密度函数（或可能性密度函数）是连续因果图能进行推理的关键,一般都是假定它们可由领域专家给出。这在实际中很难办到。文章首先给出了连续因果图的推理过程,然后讨论了如何利用已知数据集。在因果图结构已知的条件下利用参数、非参数、半参数化方法估计出连接事件的概率密度函数的途径。     

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.     

Positive Dedalus programs tolerate non-causality

Declarative networking is a recent approach to programming distributed applications with languages inspired by Datalog. A recent conjecture posits that the delivery of messages should respect causality if and only if they are used in non-monotone derivations. We present our results about this conjecture in the context of Dedalus, a Datalog-variant for distributed programming. We show that both directions of the conjecture fail under a strong semantical interpretation. But on a more syntactical level, we show that positive Dedalus programs can tolerate non-causal messages, in the sense that they compute the correct answer even when messages can be sent into the past.     

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.     

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.     

Bayesian networks in reliability

Over the last decade, Bayesian networks (BNs) have become a popular tool for modelling many kinds of statistical problems. We have also seen a growing interest for using BNs in the reliability analysis community. In this paper we will discuss the properties of the modelling framework that make BNs particularly well suited for reliability applications, and point to ongoing research that is relevant for practitioners in reliability.     

我国服务业集聚与地区城市化存在关联关系吗？——基于1987年～2011年省级面板数据格兰杰因果检验的分析

本文通过面板数据格兰杰因果检验的方法,对我国东、中、西及东北四区的各省份服务业集聚与城市化的关联关系进行了实证分析。研究发现,虽然存在着明显的区域经济差异,但四个地区各个省份服务业集聚与城市化都表现出没有或具有单向及双向的关联关系,其原因也各有不同。从区域城市化的角度而言,各个地区要因地制宜,从而在不同的发展阶段实现服务业集聚与城市化的良性互动。