基于蚁群算法的离散救援问题出救点选址研究

为解决应急物流中的出救点选址问题,建立了相应数学模型,引入蚁群算法解决问题。多数应急物流可以归为点对点的支援问题,出救点的设置应该在保证出救有效的条件下使出救点最少、救援时间最短,属于双层规划问题。双层规划问题是NP难题,可以应用蚁群算法解决。出救点选址问题在蚁群算法中可以视为蚁群的聚类,通过对信息素衰减及相邻蚂蚁的吸引作为启发因子,可以得到蚁群的聚类效果。实验结果表明,基于蚁群算法的选址问题解决方案能获得理想的选址效果,收敛速度较快。     

基于蚁群算法的粮食应急调度问题研究

为解决粮食应急调度问题,建立一个适合多应急点、多出救点的多目标优化模型。将“应急开始时间最早”和“出救点数目最少”作为优化目标,考虑每个应急点的紧急重要程度和粮食自身的消耗特点,引入相应因子。应用蚁群算法对模型进行求解,给出算法求解的具体步骤。数值算例表明,该模型可提高粮食的应急调度效率。     

基于协同差分进化的多出救点应急物资调度

主要利用差分进化算法来研究时间约束下的多出救点应急物资调度优化问题。针对传统差分进化算法搜索速度慢、易陷入局部最优解的缺点,提出一个并行协同差分进化算法,将该算法应用于时间约束下的多出救点应急物资调度优化,建立相应的数学模型,在此基础上设计相应的算法。实例验证表明,同遗传算法、标准差分进化算法相比,该算法在解决具有时间约束的多出救点应急物资调度优化问题方面具有较快的搜索速度和较好的寻优能力。     

应急资源调度的模糊规划模型

研究了出救点资源可用量及出救所需时间为三角模糊数的应急资源调度问题。以应急开始时间满意度和资源需求满意度最大为第一目标,出救点最少为第二目标构建资源调度模糊规划模型。设计了将此模型化为确定性规划模型,进而用分层序列法求解模型的方法。以算例展示了模型中各目标间的协调及模型的实用性、算法的合理性和有效性。     

基于网络模型的应急资源优化调配

针对应急管理系统中应急资源及时有效调配的难题,介绍网络扩展模型和Arc Engine技术,根据应急资源调配的特点,以应急开始时间最早、出救点个数最少为目标,结合Arc Engine网络模型,给出多个出救点应急资源调配方法,设计和实现基于GIS的应急资源优化调配可视化系统。     

溢油应急决策中的物资调度方法

针对多出救点多物资多目标应急调度问题的特点,并结合溢油敏感区等对响应时间的限制,提出了基于不同响应时间段的动态优化模型．以应急救援时间最早和出救点数目最少为优化目标,对不同响应时间段分别运用理想点法和构造剔除集合确定最优调度方案．最后通过算例验证了所提出调度方法的可行性．     

面向多层级出救点的应急物资调度模型研究*

针对我国应急救灾物资储备库系统的物资调度和运输的组织特点,依据受灾点的多层级储备库优先级模型,建立了针对多出救点、多受灾点的应急物资调度模型,实现应急开始时间最早、出救点数目最少的多目标优化,设计了模型求解方法,并给出实例验证了此模型的有效性和合理性。该模型已成功运用在国家应急救灾物资调度系统设计和玉树地震模拟物资调度方案的制定中。     

多出救点、多物资应急调度算法研究

目前物资调度方法大多是针对单出救点、单物资的调度,不能满足应急救助的实际需要。讨论在满足时间与出救点数量的约束条件下,如何解决灾害发生地多种物资调度问题,同时解决灾害发生地和物资储备仓库之间的最短路径问题。给出了两个具体的算法,并用一个实例验证了算法的可行性。     

带时限的多出救点应急物资调度模型及算法

主要研究时间限制下的多出救点应急资源调度优化问题。针对传统优化算法搜索速度慢、易陷入局部最优解的缺点,提出一种新的基于高斯函数的混沌粒子群优化算法,该算法利用高斯函数的分布曲线特性和混沌的遍历性来增强粒子群优化算法的寻优能力。将该算法应用时间限制下的多出救点应急资源调度优化,建立了满足应急时间限制下系统总费用最小的数学模型,介绍了该算法的详细实现过程。算例通过和遗传算法和标准粒子群算法进行比较,证明了其搜索速度和寻优能力的优越性。     

基于变精度粗糙集的应急调度模型

以应急调度为背景,为了提高不同精度下的不确定信息处理能力,研究了变精度应急调度问题.针对多物资、多出救点、多受灾点和时变供求约束等特点,构建了应急时间最短、成本最少的多目标应急调度模型.证明了应急响应总时间的取值范围,以此推导出模型中运输时间与运费的取值范围.在上述定理证明前提下,设计了粒子群优化算法对该模型进行求解,并将其最优目标函数值与随机模式下最优目标函数值进行对比,显现出本文所提模型与设计算法的有效性.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).