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91.
92.
Qualitative input–output (IO) analysis can be considered mostly in terms of a graph-theoretic formulation, which involves the construction and use of an adjacency matrix, derived from a binary transformation of the IO coefficient matrix. Classical attempts at qualitative IO analysis have derived the structure from the direct IO coefficient table. In more recent attempts, greater sophistication has been achieved by incorporating a degree of quantification into the qualitative analysis. Also, the concept of important coefficients (IC) has been used for the construction of the adjacency matrix. The present study is carried out along these lines for the Indian economy. 相似文献
93.
The estimation of the parameters of a continuous-time Markov chain from discrete-time observations, also known as the embedding problem for Markov chains, plays in particular an important role for the modeling of credit rating transitions. This missing data problem boils down to a latent variable setting and thus, maximum likelihood estimation is usually conducted using the expectation-maximization (EM) algorithm. We illustrate that the EM algorithm is likely to get stuck in local maxima of the likelihood function in this specific problem setting and adapt a stochastic approximation simulated annealing scheme (SASEM) as well as a genetic algorithm (GA) to combat this issue. Above that, our main contribution is to extend our method GA by a rejection sampling scheme, which allows one to derive stochastic monotone maximum likelihood estimates in order to obtain proper (non-crossing) multi-year probabilities of default. We advocate the use of this procedure as direct constrained optimization (of the likelihood function) will not be numerically stable due to the large number of side conditions. Furthermore, the monotonicity constraint enables one to combine structural knowledge of the ordinality of credit ratings with real-life data into a statistical estimator, which has a stabilizing effect on far off-diagonal generator matrix elements. We illustrate our methods by Standard and Poor’s credit rating data as well as a simulation study and benchmark our novel procedure against an already existing smoothing algorithm. 相似文献
94.
This study examines the sources of negative momentum profits by combining investor attention and the properties of common and firm-specific factors. We choose the Korean stock market as a good case to characterize the negative momentum profits identified in Asia. In both portfolio and stock analyses, a method is devised to generate return data involving the property of each common and firm-specific factor within stock groups by investor attention. This study found significant negative momentum profits within the stock group with high investor attention. This momentum effect is highly dependent on the reversed performance of the past loser portfolio, not the continued performance of the past winner portfolio, and this reversal is strongly attributable to the properties of firm-specific factors, and not those of common factors. These results are robustly consistent regardless of changes in empirical design and the consideration of influence factors, market dynamics, and other stock markets. 相似文献
95.
推动经济增长的主导因素由传统的劳动力、资本积累向创新要素数量与网络化程度转变。从来源看,区域创新源于区内自主创新与区外创新溢出。区域自主创新能力直接受创新要素禀赋条件的影响,集聚经济因素通过空间外部性作用直接影响区域创新要素集聚能力与水平。同时区域经济发展过程中形成的空间依赖产生区间创新溢出;对外开放过程中产生创新的国际溢出,都对区域创新绩效产生重要影响。实证分析结果表明,从整体上看,集聚经济与创新溢出皆对区域创新绩效有显著影响。因此,应通过强化集聚经济效应,构建开放式创新环境,提高吸收能力以充分利用创新溢出效应,并促进企业价值网与区域创新网“两网合一”,降低交易成本,不断提升区域创新绩效。 相似文献
96.
利用层次分析法(AHP)的原理与方法,提出了信息系统安全评价指标体系,建立综合分析评价模型,采用向量范数法对判断矩阵进行优化。描述了信息系统安全评价的方法和流程,计算出评价指标的综合权重。通过实例说明这一模型能对信息系统安全等级进行综合评价。 相似文献
97.
《Telecommunications Policy》2020,44(8):102003
There is a steady global trend towards “Data Localization,” laws by which data is required to be maintained and processed within the geographic boundaries of its state of origin. This development has raised concerns about its possible adverse impacts on emerging data-intensive technologies such as Cloud services/E-commerce, Big Data, Artificial Intelligence and the Internet of Things (collectively, the Embedded Infosphere). The inability to reach an international agreement on rules for cross-border data flows may have significant adverse consequences for all future users of the Internet.The basis of Data Localization is grounded in two distinct but inter-related policy models: Data Sovereignty and Trans-Border Data Flows. These two concepts have different origins. “Data Sovereignty” is derived from the historic power of a state of absolute and exclusive control within its geographic borders. Policies behind TBDFs arose in Europe following World War II, primarily motivated by Nazi use of early proto-computers to help round up Jews and others. As they have evolved, TBDF policies have been directed primarily at protecting personal data and privacy.This article first examines the issues of: 1) “Information Sovereignty” and 2) TBDFs. It then describes the arguments for and against “Data Localization,” offers some examples of strong localization policies (Russia, China), and summarizes contesting policy proposals. It then contextualizes TBDF with issues of human rights (free flow of information) and privacy.While the utility of an international agreement on TBDFs is clear, the differences in approaches are tenacious. For the free-market developed world (e.g, EU, OECD), the path forward seems to lead through policy convergence to compatible rules, with differentiated levels of data protection and accountability. It is far from clear whether these rules will address, in a mandatory way, issues of the “free flow” of information in the human rights sense. At the same time, there are countries (e.g., BRICS), representing a majority of the world's population, in which political and cultural resistance will produce stringent Cyber Sovereignty and Data Localization policies with few if any human rights components.The article concludes that the more the Internet is “localized”, the more attenuated its benefits will become. The negative consequences of Data Localization will become increasingly obvious as new, data-intensive technologies become ubiquitous, creating a condition of “Data Dependence”. It is projected that in the future the nations with the least amount of Data Localization and the most open flow of information will be the most successful in benefiting from new data-intensive embedded, networked technologies. This will most likely be characterized by values adopted as policies and practices in the EU. 相似文献
98.
Christian Max MØller 《Scandinavian actuarial journal》2013,2013(1):76-78
Abstract The present paper proposes and investigates a procedure for numerical evaluation of the transition probabilities for a time-inhomogeneous Markov process when the intensities are known (estimated). The procedure is based on Taylor-expansion of the transition probabilities linked with the Chapman-Kolmogorov equations. 相似文献
99.
探讨了外来常住人口本地化的条件:一是外来常住人口心理上的融入意愿;二是外来常住人口客观上的融入能力;三是当地政府的发展需要和承受能力。分析了外来常住人口本地化的法律障碍。提出了外来常住人口本地化的对象需求类型:一是经济权利保障;二是社会权利保障;三是文化权利保障;四是政治权利保障;五是户籍本地化。提出了当地政府提供外来常住人口本地化的供给类型:户籍本地化和权益本地化。 相似文献
100.
隐形冠军企业在成立初期依靠准确的市场定位和高度专业化在某一细分市场中占有绝对的领导地位。但随着市场透明度的提高,产品生命周期的缩短,隐形冠军面临愈发激烈的竞争,其发展空间受到压制。依据"安索夫矩阵"中企业多元化发展战略,隐形冠军只有培养自身核心能力,执行行业跨度小的相关多元化战略,开发市场前景广阔的产品,才能实现成功突围。 相似文献