Modelling daily multivariate pollutant data at multiple sites

Summary. This paper considers the spatiotemporal modelling of four pollutants measured daily at eight monitoring sites in London over a 4-year period. Such multiple-pollutant data sets measured over time at multiple sites within a region of interest are typical. Here, the modelling was carried out to provide the exposure for a study investigating the health effects of air pollution. Alternative objectives include the design problem of the positioning of a new monitoring site, or for regulatory purposes to determine whether environmental standards are being met. In general, analyses are hampered by missing data due, for example, to a particular pollutant not being measured at a site, a monitor being inactive by design (e.g. a 6-day monitoring schedule) or because of an unreliable or faulty monitor. Data of this type are modelled here within a dynamic linear modelling framework, in which the dependences across time, space and pollutants are exploited. Throughout the approach is Bayesian, with implementation via Markov chain Monte Carlo sampling.     

Low dose risk estimation via simultaneous statistical inferences

Summary.  The paper develops and studies simultaneous confidence bounds that are useful for making low dose inferences in quantitative risk analysis. Application is intended for risk assessment studies where human, animal or ecological data are used to set safe low dose levels of a toxic agent, but where study information is limited to high dose levels of the agent. Methods are derived for estimating simultaneous, one-sided, upper confidence limits on risk for end points measured on a continuous scale. From the simultaneous confidence bounds, lower confidence limits on the dose that is associated with a particular risk (often referred to as a bench-mark dose ) are calculated. An important feature of the simultaneous construction is that any inferences that are based on inverting the simultaneous confidence bounds apply automatically to inverse bounds on the bench-mark dose.     

欠发达地区基础设施过度投资的机理和危害

地方政府之间的经济增长指标竞争导致对公用基础设施过度的投资需求。建筑企业、原材料供应商和劳动力的竞争使得投资方有获得超额利润的可能。过度投资可能引发市县政府的财政危机,同时严重破坏了正常的市场秩序,并提供了产生腐败的空间与土壤。     

Local spatial data infrastructure, Trujillo-Peru

The development of a Municipal Information System, or currently better known as a local spatial data infrastructure, is considered complex due to the required inter-institutional relationships. In many developing countries Geographical Information Systems (GISs) are introduced but the benefits are modest as no changes take place in technical and organisational structure of organisations. Digital databases and computer-aided design (CAD) maps are mushrooming in great variety within different private and public institutions, municipal organisations and even within single departments and with structures similar to the paper period and thus operating on a stand-alone basis.Many national mapping agencies are not able to provide large-scale digital urban base maps, while the absence or low quality of cadastres makes those basic core data sets unavailable or inaccessible. The result is that duplication and incompatible data are frequently observed and also donor-driven stand-alone projects have a limited impact through the lack of institutional embedding and are not able to mature from the project to the institutional level. However, a positive sign is that there is an increasing awareness among data producers and consumers that investments in the development of digital data sets should be combined to reduce costs and increase benefits from especially GIS, and information and communication technology (ICT) in general.Within Trujillo a long-term vision was developed to make full use of ICT and GIS to modernise all operations of the Municipality to increase the efficiency and effectiveness of its tasks. However, large investments are not feasible due to the very limited municipal budgets. To guarantee the support of the municipal council, short-term results are required. This paper describes three ‘products’ as part of the vision to develop through a step-by-step approach a local spatial data infrastructure for Trujillo.The three, rather different, products are:

1. fiscal cadastre, to increase municipal revenues through property taxation;

2. an ‘environmental atlas’ based on a compatible spatial and attribute data sets from a variety of organisations; and

3. a municipal website with interactive GIS and meta data information.

The paper concludes with some comments on the institutional and political requirements for the successful development of a local spatial data infrastructure and stresses that such an infrastructure is not a product but an incremental development process that will progress only in case such a process is simple, cost effective, user-friendly, and flexible with clear products.Political interest and institutional stability and genuine interest for inter-institutional cooperation will add much to the success of this process.     

匿名双向认证与密钥协商新协议

分析了一种新的匿名双向认证与密钥协商协议,它使移动网络向用户提供匿名服务, 访问网络与非法窃听者无法获知用户的身份信息,保证了用户身份、所在位置和行踪信息的机密性。该协议可以实现通信双方的相互认证,产生的会话密钥对通信双方是公正的。协议将双钥体制和单钥体制有机的结合起来,结构简单,安全高效。     

我国林业基本建设投资的效益分析

随着林业经营思想的转变，我国林业基本建设投资也发生了变化。该文在论述我国林业基本建设投资资金形成和发展的基础上，对不同领域的投资，从其产生的直接效益和最终效益两个层面进行了分析，并从选择投资项目、确定最优项目和加强管理等方面，提出了增加我国林业基本建设投资效益的对策。     

浅谈生态伦理及其教育问题

生态道德教育是一个普遍性的社会伦理问题。生态危机的特征 ,生物共同体的联系以及我国生态环境的现状 ,都客观地要求我们必须注重人与自然界的和谐发展 ,加强全民性的生态道德教育。     

开展我国环境审计的新思考

在我国,环境审计对于国家审计、内部审计和民间审计来说都是一个新内容。作为环境管理系统的重要组成部分,环境审计具有重大的意义。因此,建立健全环境审计制度,采取切实可行的措施,是环境管理和环境审计的重要任务。     

加窗技术的改进证书吊销机制

分析了现有证书吊销机制在灵活性、可升级性和及时性中的缺陷,针对现有新型证书吊销机制,提出了一种结合加窗证书吊销和增量CRL机制的证书吊销机制。该机制结合传统CRL机制和在线证书状态机制的优点,既能满足不同的安全需求,又能有效减少资源开销,满足验证者的实时性证书验证请求。     

高等院校科技基础条件平台建设的浅析

高等院校的科技基础条件平台是学校整体水平与实力的综合表征,如何在实践中推动科技基础条件平台建设,是摆在高等院校面前无法回避的现实问题。科技基础条件平台是实现科技自主创新的源泉,是推动学科交叉,获得原创性科学成果的重要途径。高等院校科技平台建设要加强顶层设计、整合资源、完善共享机制,使得高等院校科技工作实现可持续发展。