信息系统等级保护测评实践

该文针对社会发展对信息化的依赖程度越来越高,而保障重要信息系统安全也是维护国家安全、保障社会稳定的重要组成部分这一事实.随着重要信息系统等级保护工作的深入,信息系统等级自测评与差距分析得到了广泛重视.文章系统阐述了自测评实践中的基本流程、测评方法与测评成果.  

Shape-adaptive radial basis functions

Radial basis functions for discrimination and regression have been used with some success in a wide variety of applications. Here, we investigate the optimal choice for the form of the basis functions and present an iterative strategy for obtaining the function in a regression context using a conjugate gradient-based algorithm together with a nonparametric smoother. This is developed in a discrimination framework using the concept of optimal scaling. Results are presented for a range of simulated and real data sets.  

Gamma mixture models for target recognition

This paper considers a mixture model approach to automatic target recognition using high-resolution radar measurements. The mixture model approach is motivated from several perspectives including requirements that the target classifier is robust to uncertainty in amplitude scaling, rotation and translation of the target. Estimation of the model parameters is achieved using the expectation-maximisation (EM) algorithm. Gamma mixtures are introduced and the re-estimation equations derived. The models are applied to the classification of high-resolution radar range profiles of ships and results compared with a previously published self-organising map approach.  

Image fusion in open-architecture PACS-environment

Multimodal digital imaging is common in many fields of diagnosis and therapy planning - there is great interest in matching globally, fusing or registering data from the same part of the body. In practice, there are still difficulties in customizing image fusion in hospitals. Efficient routine use of image fusion requires, among others, an image management infrastructure - a picture archiving and communication system (PACS) - to provide storage of image data in a standard digital format, intelligent image management and fault-tolerant high-speed image networking. In order to customize image fusion, advances in both fusion software and hardware are also needed. The algorithms should be automatic, fast and accurate enough. Registration of multimodal data also creates a need for different display techniques and user-friendly interfaces. Image fusion has been impractical and too tedious to be performed in routine work, but in the future, fused images will be used in clinical practice - even in teleradiological consultation.  

Robust regression methods for computer vision: A review

Regression analysis (fitting a model to noisy data) is a basic technique in computer vision, Robust regression methods that remain reliable in the presence of various types of noise are therefore of considerable importance. We review several robust estimation techniques and describe in detail the least-median-of-squares (LMedS) method. The method yields the correct result even when half of the data is severely corrupted. Its efficiency in the presence of Gaussian noise can be improved by complementing it with a weighted least-squares-based procedure. The high time-complexity of the LMedS algorithm can be reduced by a Monte Carlo type speed-up technique. We discuss the relationship of LMedS with the RANSAC paradigm and its limitations in the presence of noise corrupting all the data, and we compare its performance with the class of robust M-estimators. References to published applications of robust techniques in computer vision are also given.  

Distributed intelligent architecture for logistics (DIAL)

An ideal logistics problem is considered as a network flow problem which generates a logistics plan and subsequently executes the plan. A real-world logistics plan is different from its ideal counterpart modeled as a network flow problem in the sense that each node of the logistics graph is operated independently with disparate objectives. In contrast to the nodes of a network flow problem, agents are considered as software entities which embody elegant reasoning ability to justify their own actions towards individual objectives, and also interact with other agents. Hence, a group of agents or a multiagent system is best suited to solve real-world logistics problems with each agent representing a node of the graph. We have built a three-tier framework where a customer's problem can be decomposed and assigned to all the agents which together generate a logistics plan. We employ two simulation software as planning tools which enable us to simulate appropriate events. The key ideas behind this paper are large-scale multiagent architectural modeling issues (scalability), computation task control, information sharing among several customers, and a problem solving procedure before the planning process. The problem solving procedure is considered as determining the computational tasks required to be invoked to initiate the planning process. We describe the implementation of the framework.  

Self-Repairing Mechanical Systems

This paper reviews several types of self-repairing systems developed in the Mechanical Engineering Laboratory. We have developed a modular system capable of self-assembly and self-repair. The former means a set of units can form a given shape of the system without outside help; the latter means the system restores the original shape if an arbitrary part of the system is cut off. We show both two-dimensional and three-dimensional unit designs, and distributed algorithms for the units.  

A Regularized Contact Model with Asymmetric Damping and Dwell-Time Dependent Friction

A general regularized contact model, including normal compliance, energydissipation, and tangential friction, is described in this paper. Thenormal damping coefficient is formulated as a function of the coefficientof restitution e and the impact velocity only; the results areenergy-consistent, with continuous force progression at the beginningand end of the impact, for both small and large values of e.The introduced seven parameter friction model based on an explicitformulation of the friction forces is suitable for real-timeapplications. The friction forces are split into its sliding andsticking contribution and a temporal lag effect, the dwell-time, isincluded using a novel dwell-time dependent stick state variable. Several examples are presented to demonstrate the features of thisgeneral contact model. The simulation results for a double pendulumhitting a plane are obtained, and a comparison with a benchmark problem shows the model behavior is in good agreement with published results.  

A daily weather generator for use in climate change studies

This paper describes the development of a weather generator for use in climate impact assessments of agricultural and water system management. The generator produces internally consistent series of meteorological variables including: rainfall, temperature, humidity, wind, sunshine, as well as derivation of potential evapotranspiration. The system produces series at a daily time resolution, using two stochastic models in series: first, for rainfall which produces an output series which is then used for a second model generating the other variables dependent on rainfall. The series are intended for single sites defined nationally across the UK at a 5 km resolution, but can be generated to be representative across small catchments (<1000 km²). Scenarios can be generated for the control period (1961–1990) based on observed data, as well as for the UK Climate Impacts Programme (UKCIP02) scenarios for three time slices (2020s, 2050s and 2080s). Future scenarios are generated by fitting the models to observations which have been perturbed by application of change factors derived from the UKCIP02 mean projected changes in that variable. These change factors are readily updated, as new scenarios become available, and with suitable calibration data the approach could be extended to any geographical region.  

Structural simulation of tree growth and response

Published online: 5 February 2003