Statistical analysis of dependent competing risks model in accelerated life testing under progressively hybrid censoring using copula function

This article considers statistical analysis of dependent competing risks model from Weibull distribution in accelerated life testing, in which copula function is used to examine the dependence structure between competing failure modes. We derive the maximum likelihood estimates, the approximate, and Bootstrap confidence intervals of the parameters. The effects of different dependence structures on the estimates of parameters are investigated. The simulation is given to compare the performance of the estimates when the competing failure modes are dependent with those when the failure modes are independent. Finally, one dataset was used for illustrative purpose in conclusion.     

A general long-term aging model with different underlying activation mechanisms: Modeling,Bayesian estimation,and case influence diagnostics

In this paper we propose a general cure rate aging model. Our approach enables different underlying activation mechanisms which lead to the event of interest. The number of competing causes of the event of interest is assumed to follow a logarithmic distribution. The model is parameterized in terms of the cured fraction which is then linked to covariates. We explore the use of Markov chain Monte Carlo methods to develop a Bayesian analysis for the proposed model. Moreover, some discussions on the model selection to compare the fitted models are given, as well as case deletion influence diagnostics are developed for the joint posterior distribution based on the ψ-divergence, which has several divergence measures as particular cases, such as the Kullback–Leibler (K-L), J-distance, L₁ norm, and χ²-square divergence measures. Simulation studies are performed and experimental results are illustrated based on a real malignant melanoma data.     

Scrambled systems: the (im)mobilities of ‘storm Desmond’

This article examines a 3-day blackout, triggered by a ‘1-in-100-year’ rainfall event. Storms and floods account for almost three-quarters of weather-related disasters, and are typically accompanied by cascading infrastructure failures, which pattern and amplify their effects in highly significant ways. Such disruptions reveal aspects of everyday life that ordinarily remain obscure, including capacities for resilience embodied in people, cities and infrastructure. The article proposes that disruption events be understood in terms of ‘scrambles’, as they involve abrupt demobilisation and remobilisation of a range of people and materials. The article firstly examines the astonishing capacity for failure latent in ‘pervasively powered’ arrangements, as well as the many ways in which people and things were ‘scrambled’ in response. The article then proceeds to explore the ways in which vulnerabilities result in part from mobilisation in response to previous disruption events, before examining the ‘circuits’ that link far-flung places in mobile disaster geographies, global patterns of electricity dependence, the rise of data overload in the ‘cloud’ to carbon overload in the atmosphere. The article concludes by presenting further evidence in support of the thesis that disruptions and disasters are part of a ‘new normal’, and what this means for prevailing sociotechnical arrangements reliant on ‘sunk’ infrastructure.     

Internet risks and expert views: a case study of the insider perspectives of youth workers in Hong Kong

This study collects and analyses the viewpoints of front-line youth workers regarding the notion of ‘Internet risks’. Previous studies have examined and discussed various dangers of the Internet. Parental, school, and governmental interventions are often called for by those concerned. The implicit assumption is that these are the people who possess the expertise to tackle the problems at hand. Through participation in three forums focusing on ‘Internet risks’, and in-depth interviews with 10 such ‘experts’ in Hong Kong, the study examines if this is a valid assumption. It finds that experts perceive Internet risks rather differently. In addition to the more conventional views about content, contact and conduct risks, our interviewees are aware that a new order is quickly emerging in the new media environment. Despite being considered as ‘experts’, they do not necessarily know how to tackle the so-called ‘youth-at-risk’. Rather, they are exploring how they would capitalize on the opportunities offered by the developments. The key findings highlight the need to critically review the notion of ‘Internet risks’. As with other risk frameworks, the ultimate aim is to develop intervention programmes. In this regard, risks are often treated as concrete problems that can be solved. Youth experts, however, find that the changing scope, speed and persistence of communication in today's information society present the biggest challenge in youth work. The existing framework of risks was unable to describe and account for such risks. In response, Internet risk has to be reconceptualized so that more updated, relevant and imaginative intervention can be introduced.     

我国财政赤字和货币供应量联动性的实证模型分析

近期以来国际金融危机的加深,进一步揭示了一国财政赤字与宏观经济之间的深刻关联。进入新世纪以来,我国运用财政赤字的手段和方法不断改进,对于我们应对国际金融市场的动荡、促进内需和经济增长起到了很大作用。但同时,财政赤字与货币发行量之间不可调和的正向关系,也给我国经济体系带来了一定的隐患。因此,通过理论梳理与实证分析来理清赤字规模和货币供应量之间的关系,有助于我们今后宏观经济管理手段和金融市场监管能力的提升。     

抗争、民主与治理:全球治理下的抗争政治研究

随着20世纪60年代西方社会运动的兴起,西方国家的国内政治由此发展出有别于常规制度、正式政治的独特政治形态——抗争政治。诸多的理论认为,这一政治形态对其国内政治的民主和治理都具有积极的促进作用。本文通过对抗争政治历程的研究,指出:一方面,全球化及反全球化运动、全球风险社会都使得全球政治和治理发生大转型,由此引发全球社会运动,抗争从国内走向国际;而另一方面,抗争功能也具有局限性。同时认为,国内和国际层面上的抗争政治,关注全球抗争与民主、治理的关系,呈现出与常规政治不同的性质、特点和功能,具有重大的理论和实践价值。     

全球变暖与历史学发展的四个论题

气候变化科学对以人类为中心的人文主义史学具有重要影响。科学家关于气候变化的观点不仅挑战了人类支撑历史学这门学科的观念,而且挑战了后殖民与后帝国时代历史学家在过去20年来,回应战后非殖民地化与全球化势态时所运用的分析策略。现在的历史知识构建以人文主义史学关于人类历史与自然史古老区分的失效为历史学科的大前提,将人类视为一种地质力量的人类世观念严格限定了人文主义史学,要求资本主义历史与地球和人类进化的更大尺度的历史进行对话。有记载的历史与深层历史进行这种对话是一个探索历史理解界限的过程。     

P2P系统中的著作权侵权责任探析

P2P系统的应用,使得作品的传播变得更加方便与快捷,也使得对作品的侵权越来越成为可能,为了寻求文化艺术作品的传播与版权人利益保护之间的平衡,从网络技术和法律方法相结合的角度,研究了P2P系统中的著作权侵权问题。认为P2P系统中的著作权侵权应当适用过错责任的归责原则。根据这一原则,只要ICP所提供的内容侵权,就需要承担侵权责任,软件提供商在明知或应知软件侵权的情况下仍然提供服务也应当承担侵权责任,软件经营者则可以适用＂通知与删除＂规则,在有证据表明有人利用P2P系统侵害著作权的情况下,软件经营者应当停止相应服务,否则就应当承担侵权责任。而对于P2P用户,则可要求其对其共享文件夹中的侵权作品承担侵权责任。     

我国企业海外撤资的实物期权分析

由于世界经济形势变化、地区政局不稳和企业对国际市场的误判,我国部分对外投资企业亏损严重,面临着从海外撤资的决择。利用实物期权法分析企业退出问题,参照贝尔曼方程,构建撤资决策的实物期权模型,分析对外投资企业撤资决策的价值。算例分析表明,对外投资企业选择的贴现率、利润的波动率和撤资成本的变化均能影响撤资的时机和方式。我国对外投资企业应根据形势变化和自身实力,不断加强自身抵抗风险的能力,灵活选择趁机抢占国外市场的进攻策略,或尽早撤出以获得放弃期权价值的防守策略。     

Risk-Informed Requirements for Design and Assessment of Structures Under Temporary Use

The relatively high failure rates, with important consequences in many cases, suggest that the implicitly acceptable risk levels corresponding to temporary civil engineering structures and activities might exceed the bounds of normally acceptable levels associated with different societal activities. Among other reasons, this may be attributed to the lack of a rational approach for the assessment of risks associated with the different technologies supporting these activities in general, and for structures in particular. There is a need for establishing appropriate target reliability levels for structures under temporary use taking into account specific circumstances such as reduced risk exposure times. This issue is being addressed in this article. Acceptance criteria for building-structure-related risks to persons obtained in prior studies are adapted to the special circumstances of nonpermanent risk exposure. Thereby, the general principle followed is to maintain the same risk levels per time unit as for permanently occupied buildings. The adaptation is based on the statistical annual fatality rate, a life safety risk metric that allows for a consistent comparison of risks across different societal activities and technologies. It is shown that the target reliability indices taking account of the temporary use of buildings might be significantly higher than the values suggested for permanently used structures.