A new procedure to estimate the rainfall erosivity factor based on Tropical Rainfall Measuring Mission(TRMM) data

Soil erosion by water is the most important land degradation problem worldwide.In this paper a new procedure was developed to estimate the rainfall-runoff erosivity factor(R)based on Tropical Rainfall Measuring Mission(TRMM)satellite-estimated precipitation data,which consists of 3-h rainfall intensity data.In this method,R was calculated as the product of the maximum 180-min rainfall intensity and the rainfall energy.This procedure was applied to the Daling River basin in Liaoning Province,China,R in terms...     

一种应急救灾飞艇部署与规划方法研究

飞艇具有高分辨、大覆盖、可定点观测及可快速部署等特点。开展应急救灾飞艇快速部署与规划研究能够减少灾害现场监测盲目性,提升救灾科学决策能力,是任务规划领域研究的热点问题之一。提出了一种应急救灾飞艇快速部署与规划新方法,综合考虑飞艇部署与规划问题,建立了基于信息熵的飞艇最优化部署模型,并在此基础上,提出了一种最大执行任务的约束满足任务规划算法,引入相容性矩阵和遗传算法,开展算法求解,降低规划复杂度。最后通过仿真实验,验证了所提方法的有效性。     

A fast and robust bulk-loading algorithm for indexing very large digital elevation datasets II. Experimental results

The spatial indexing of eventually all the available topographic information of Earth is a highly valuable tool for different geoscientific application domains. The Shuttle Radar Topography Mission (SRTM) collected and made available to the public one of the world's largest digital elevation models (DEMs). With the aim of providing on easier and faster access to these data by improving their further analysis and processing, we have indexed the SRTM DEM by means of a spatial index based on the kd-tree data structure, called the Q-tree. This paper is the second in a two-part series that includes a thorough performance analysis to validate the bulk-load algorithm efficiency of the Q-tree. We investigate performance measuring elapsed time in different contexts, analyzing disk space usage, testing response time with typical queries, and validating the final index structure balance. In addition, the paper includes performance comparisons with Oracle 11g that helps to understand the real cost of our proposal. Our tests prove that the proposed algorithm outperforms Oracle 11g using around a 9% of the elapsed time, taking six times less storage with more than 96% of page utilization, and getting faster response times to spatial queries issued on 4.5 million points. In addition to this, the behavior of the spatial index has been successfully tested on both an open GIS (VT Builder) and a visualizer tool derived from the previous one.     

基于协商对策的卫星任务规划冲突消解

主要对卫星任务规划过程中预处理阶段的目标冲突进行研究.为了更合理地确定卫星应用任务的时间窗口及个时间窗口的属性值,更有效地利用昂贵的卫星资源,首先对卫星任务规划预处理阶段的目标冲突进行了分析,给出了冲突的数学描述,针对冲突的特点提出了基于协商对策的冲突消解方法及协商流程,最后通过实例分析验证了方法在卫星任务规划中对目标冲突消解的有效性.     

武器装备体系能力生成过程

针对武器装备体系能力的特点,通过对能力需求的分析,提出一种武器装备体系的能力生成方法。在建立“从硕向下”使命目标到能力的分解框架的基础上,阐释了目标分解、行动分解、功能分解和能力分析的具体过程,给出了能力需求到能力方案的转化思路。通过对能力需求和现有能力水平的比较分析,确定了最终发展的能力,为能力生成和评估提供了一定的思路。     

一种改进的主动规则的系统执行模型

主动规则及规则处理机制一直是主动数据库研究的薄弱环节,主要表现为:(1) 语义不够丰富;(2) 缺乏基础语义;(3) 缺乏对规则处理的层次化和结构化的描述.为弥补上述不足,对规则处理机制赋予了丰富的规则延伸语义,根据语义的要求,用规则处理树层次化和结构化地描述规则处理过程对系统状态的影响.新的系统执行模型和扩展后的事务使我们能够提出一种支持丰富语义的规则处理算法.与其他规则处理算法相比,该算法实现了新语义,并利用了递归技术,能更好地吻合规则处理过程.     

试论企业信息安全的开放式标准解决方案

本文讨论了企业信息安全解决方案。从身份验证和存取控制、消息发布和工作流、电子商务、安全管理和任务控制管理、开发启用安全性的应用等五个方面论述企业网络的安全体系结构。     

Optimal sequencing of warm standby elements

Warm standby redundancy has been used as an effective design technique for improving the reliability of a system while achieving the compromise between restoration cost and operation cost of standby elements. This paper considers the optimal standby element sequencing problem (SESP) for 1-out-of-N: G heterogeneous warm-standby systems. Given the desired redundancy level and a fixed set of element choices, the objective of the optimal system design is to select the initiation sequence of the system elements so as to minimize the expected mission cost of the system while providing a certain level of system reliability. Based on a discrete approximation of time-to-failure distributions of the system elements, the system reliability and expected mission cost are evaluated using an iterative procedure. A genetic algorithm is used as an optimization tool for solving the formulated SESP problem for 1-out-of-N: G warm-standby systems with non-identical elements. As illustrated through examples, results generated using the suggested methodology can facilitate the system reliability versus cost trade-off study, which can further assist in the decision making about the best standby policy for fault-tolerant system designs.