An Intelligent Decision Support System for Management of Floods

Integrating human knowledge with modeling tools, an intelligent decision support system (DSS) is developed to assist decision makers during different phases of flood management. The DSS is developed as a virtual planning tool and can address both engineering and non-engineering issues related to flood management. Different models (hydrodynamic, forecasting, and economic) that are part of the DSS share data and communicate with each other by providing feedback. The DSS is able to assist in: selecting suitable flood damage reduction options (using an expert system approach); forecasting floods (using artificial neural networks approach); modeling the operation of flood control structures; and describing the impacts (area flooded and damage) of floods in time and space. The proposed DSS is implemented for the Red River Basin in Manitoba, Canada. The results from the test application of DSS for 1997 flood in the Red River Basin are very promising. The DSS is able to predict the peak flows with 2% error and reveals that with revised operating rules the contribution of Assiniboine River to the flooding of Winnipeg city can be significantly reduced. The decision support environment allows a number of “what-if” type questions to be asked and answered, thus, multiple decisions can be tried without having to deal with the real life consequences.     

Modelling of shear strength of rockfills used for the construction of rockfill dams

This paper presents the results of examination of shear properties of rockfills used for the construction of rockfill dams. Based on the results of a large number of experiments, mathematical model of the shear strength of the rockfill was derived, as a function of normal stress, initial compaction and uniaxial compressive strength of intact rock material. Using this model it is possible to make a realistic assessment of the shear strength of a rockfill for the Preliminary Design. The experimental data used for modelling were obtained by direct shear tests performed in the majority at the “Jaroslav Cerni” Institute for Development of Water Resources in Belgrade, Serbia.     

Improving network security using genetic algorithm approach

With the expansion of Internet and its importance, the types and number of the attacks have also grown making intrusion detection an increasingly important technique. In this work we have realized a misuse detection system based on genetic algorithm (GA) approach. For evolving and testing new rules for intrusion detection the KDD99Cup training and testing dataset were used. To be able to process network data in real time, we have deployed principal component analysis (PCA) to extract the most important features of the data. In that way we were able to keep the high level of detection rates of attacks while speeding up the processing of the data.     

效率为98%的单相和三相单级交流一直流变换器拓扑结构

目前在电力电子技术研究领域,具有隔离和功率因数校正功能的单级AC-DC变换器,均是依赖于全桥整流的新型变换器。当前的单相AC-DC变换器是基于传统的脉宽调制(PWM)变换方法实现的,它至少包括3个不同的功率信号处理级:全桥整流器、BOOST PFC变换器和串联隔离式全桥DC-DC变换器,共用到14个开关器件和3个磁性元件,这些都对变换器的效率、尺寸和成本限制产生影响。本文所介绍的混合变换方法,实现了一种新型单级AC-DC变换器拓扑结构,是一种只包括3个开关器件和1个磁性元件的非桥型PFC变换器。这种变换器具有98%左右的效率、0.999的功率因数和总共仅1.7%的谐波畸变。三相整流器包含了3个这样的单相整流器,它利用了特斯拉三相转换系统的优点,可以进行三相系统的输入功率到直流输出功率的瞬态转换,具有高频光隔离,0.999的功率因数,低谐波畸变(1.7%),较小的尺寸和成本等特点,而且效率达到了98%。。     

Improved coloristic properties and high NIR reflectance of environment-friendly yellow pigments based on bismuth vanadate

Herein, fine powders of yellow pigments based on BiVO₄ were successfully prepared in two crystalline forms, tetragonal zircon-structured and monoclinic scheelite-structured, through a ethylene glycol-assisted method subjected to a thermal treatment at two different temperatures. The obtained materials were brightly colored with different hues of yellow, exhibited high reflection in the near-infrared region and showed visible luminescence under excitation by UV light. The new preparation method had a considerable effect on chromatic properties of the prepared scheelite-structured BiVO₄ pigments. The sample with the most vivid and bright shade of yellow was found to have the L^*a^*b^* and L^*C^*_ab h^*_ab color coordinates of (87.28, 0.37, 91.53) and (87.28, 91.53, 89.79), which are indicative of exceptionally good chromatic properties superior and/or comparable to those of other inorganic yellow pigments, both commercially available and recently described. In addition, the NIR reflectance of this powder was very high (≥?80%).     

Topological Editing of Cross-Relaxation Networks

We have used the elements of graph theory to describe NMR cross-relaxation networks in macromolecules and to analyze different experiments used for topological editing. We propose a new experiment, block decoupled NOESY (B.D. NOESY), that splits the cross-relaxation network of a macromolecular system into two noninteracting subdomains. Splitting is achieved by arranging for the effective z-components of the magnetization in one subdomain, as viewed from the other subdomain, to be zero. The B.D. NOESY experiment, in favorable cases, can usefully simplify the analysis of cross-relaxation spectra by removing certain ambiguities. We demonstrate the method by separating the aromatic resonances from the rest of the cross-relaxation network of a small globular protein: turkey ovomucoid third domain, M_r 6000. The resulting spectrum provides a clearer picture of cross-relaxation pathways that involve only aromatic or only aliphatic spins. By comparing the B.D. NOESY spectrum with the normal NOESY spectrum, we were able to identify cross peaks that contain contributions from indirect magnetization transfer (spin diffusion) mediated by the aromatic side chains. In the terminology of graph theory, these experiments decompose topological networks of cross-relaxation into two subgraphs, the join of which generates the original graph.     

An improvement in the calculation of the magnetic field for an arbitrary geometry coil with rectangular cross section

Hong Lei, Lian‐Ze Wang and Zi‐Niu Wu presented new simple and convenient solutions of the magnetic field for an arbitrary geometry coil with rectangular cross section. They treated two types of basic forms: the trapezoidal prism segment and curved prism segment. The curved prism segment has been divided into a series of small trapezoidal prism segments with the same cross section and its magnetic field is a vector sum of the individual fields created by each small trapezoidal prism conductor. For one trapezoidal prism conductor the magnetic field is obtained by 1‐D integrals using Romberg numerical integration. In this paper, we give a completely analytical solution of these 1‐D integrals that considerably saves the computational time especially in the computation of the magnetic field nearby the conductor surface, at the conductor surface and inside the conductor. From obtained analytical expressions the treatment of singularities can be easily done. Also, we tested four types of numerical integration (Gaussian, Romberg, Simpson and Lobatto) to find the most convenient singularity treatment of 1‐D integrals. These obtained results are compared with those obtained analytically so that one can understand the advantage of the proposed approach. The paper points out on the accuracy and the computational cost. Copyright © 2005 John Wiley & Sons, Ltd.     

Aeroelastic applications of the Connection Machine

This paper describes the implementation of a dynamical systems approach to aeroelastic analysis using the Connection Machine model 2 (CM-2). Through numerical simulation, the regions of harmonic and chaotic behavior in the δ,R_x (velocity, in-plane load) plane have been examined in detail. These regions are of interest in evaluation of the fatigue life of fluttering plates. The CM-2 computer architecture allows the removal of many of the previous simplifying and limiting assumptions regarding the prediction of the stability regions maps. Owing to its high-speed prediction capability, the CM-2, with framebuffer, offers 'real-time' display of the solution as it evolves during the prediction process. This feature gives insight into the fundamental way in which the solution evolves. This is essential in defining the scenarios describing roads to chaotic behavior of the dissipative dynamical systems.