美国"新经济"对中国的启示

美国“新经济”是以现代高新技术为基础的知识密集型经济,具有与传统经济相比的新的特征,带来了美国经济的繁荣和发展。在面临全球经济一体化的形势下,美国新经济对促进中国经济的发展和提高国际竞争力都有一定的借鉴和启发意义。     

Markov chain Monte Carlo methods for high dimensional inversion in remote sensing

Summary.  We discuss the inversion of the gas profiles (ozone, NO₃, NO₂, aerosols and neutral density) in the upper atmosphere from the spectral occultation measurements. The data are produced by the 'Global ozone monitoring of occultation of stars' instrument on board the Envisat satellite that was launched in March 2002. The instrument measures the attenuation of light spectra at various horizontal paths from about 100 km down to 10–20 km. The new feature is that these data allow the inversion of the gas concentration height profiles. A short introduction is given to the present operational data management procedure with examples of the first real data inversion. Several solution options for a more comprehensive statistical inversion are presented. A direct inversion leads to a non-linear model with hundreds of parameters to be estimated. The problem is solved with an adaptive single-step Markov chain Monte Carlo algorithm. Another approach is to divide the problem into several non-linear smaller dimensional problems, to run parallel adaptive Markov chain Monte Carlo chains for them and to solve the gas profiles in repetitive linear steps. The effect of grid size is discussed, and we present how the prior regularization takes the grid size into account in a way that effectively leads to a grid-independent inversion.     

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。     

IT教学中教学方法的探讨

教学方法是实现教学目的所采用的途径和手段。信息产业的高速发展要求教育者不断改进教学方法。针对目前 IT教学的情况 ,本文对教学方法从七个方面进行了探讨 :考试的重点、理论课程与实验课程的安排、教材的更新、学生创新能力的培养、教学活动的方法、与学生的交流、教学模式的多样化     

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。     

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。     

审视经济全球化

由于各国经济发展的不平衡,经济全球化的当代特征表现为三角化、区域一体化和跨国公司的迅速崛起。经济全球化正在改变现有政治格局,推动世界政治朝全球性方向演进并形成全球性的治理机构或协调治理形式。在以发达国家为主导、跨国公司为主要动力的经济全球化过程中,中国作为发展中国家在国际竞争方面处于弱势,这要靠全党全民运用自己的智慧和力量,利用自己已经具备的各种有利条件去应对全球化的挑战。从人类社会经济形态演进的自然历史过程看,经济全球化不过是资本主义的社会化生产和市场全球性扩张的新的历史阶段。从马克思的立场看,全球化将会是资本主义时代的终结,并为社会主义社会的到来做好准备,随全球化而来的将是一个更加美好的新世界。     

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。