Towards modelling of a trabecular bone

Trabecular bone (lightweight spongy bone) comprises of a complex arrangement of plates and struts at micro level that make it anisotropic. Osteoporosity (leading to fracture) is a common problem in old age which makes the bone weak due to increased porosity. Considerable two dimensional data in the form of images is available on the porous structure of the bone, however this needs to be related to the macro-level anisotropic properties. This preliminary study aims to examine whether topological anisotropy can be related to elastic anisotropy. Simple three dimensional structured meshes comprising of elements with different material properties are used to simulate the porous structure. Homogenised elastic properties are evaluated and these are compared with a two dimensional topology anisotropy indicators. For the simple problems considered it appears that topological anisotropy cannot be directly linked to elastic anisotropy.     

Structural optimization based on topology optimization techniques using frame elements considering cross-sectional properties

This paper discusses a new structural optimization method, based on topology optimization techniques, using frame elements where the cross-sectional properties can be treated as design variables. For each of the frame elements, the rotational angle denoting the principal direction of the second moment of inertia is included as a design variable, and a procedure to obtain the optimal angle is derived from Karush–Kuhn–Tucker (KKT) conditions and a complementary strain energy-based approach. Based on the above, the optimal rotational angle of each frame element is obtained as a function of the balance of the internal moments. The above methodologies are applied to problems of minimizing the mean compliance and maximizing the eigen frequencies. Several examples are provided to show the utility of the presented methodology.     

基于风险指标的干旱期水资源系统运行优化分析

根据干旱期水资源系统运行性能分析特征,建立了基于供水可靠性最大、供水破坏恢复能力最强以及单一时段破坏深度最小等风险指标,同时考虑了城市和农业供水优先权问题的多目标混合整数规划模型．在实例研究中,运用多目标决策法中的协调规划原理,通过评价任一目标点与理想点的欧氏距离,获得多目标问题的最佳权衡解．计算结果表明,该多目标混合整数规划模型对解决需要考虑供水优先权的干旱期水库运行策略优化问题是可行而有效的．     

改进的飞蛾扑火优化算法在网络入侵检测系统中的应用

针对当前网络入侵检测中的数据量较大、数据维度较高的特点,将飞蛾扑火优化（MFO）算法应用于网络入侵检测的特征选择中。鉴于MFO算法收敛过快、易陷入局部最优的问题,提出一种融合粒子群优化（PSO）的二进制飞蛾扑火优化（BPMFO）算法。该算法引入MFO螺旋飞行公式,具有较强的局部搜索能力;结合了粒子群优化（PSO）算法的速度更新方法,让种群个体随着全局最优解和历史最优解的方向移动,增强算法的全局收敛性,从而避免易陷入局部最优。仿真实验以KDD CUP 99数据集为实验基础,分别采用支持向量机（SVM）、K最近邻（KNN）算法和朴素贝叶斯（NBC）3种分类器,与二进制飞蛾扑火优化（BMFO）算法、二进制粒子群优化（BPSO）算法、二进制遗传算法（BGA）、二进制灰狼优化（BGWO）算法和二进制布谷鸟搜索（BCS）算法进行了实验对比。实验结果表明,BPMFO算法应用于网络入侵检测的特征选择时,在算法精度、运行效率、稳定性、收敛速度以及跳出局部最优的综合性能上具有明显优势。     

基于改进贝叶斯优化算法的CNN超参数优化方法

CNN框架中,如何对其模型的超参数进行自动化获取一直是一个重要问题。提出一种基于改进的贝叶斯优化算法的CNN超参数优化方法。该方法使用改进的汤普森采样方法作为采集函数,利用改进的马尔可夫链蒙特卡罗算法加速训练高斯代理模型。该方法可以在超参数空间不同的CNN框架下进行超参数优化。利用CIFAR-10、MRBI和SVHN测试集对算法进行性能测试,实验结果表明,改进后的CNN超参数优化算法比同类超参数优化算法具有更好的性能。     

Structural health monitoring system based on multi-agent coordination and fusion for large structure

In practical applications of structural health monitoring technology, a large number of distributed sensors are usually adopted to monitor the big dimension structures and different kinds of damage. The monitored structures are usually divided into different sub-structures and monitored by different sensor sets. Under this situation, how to manage the distributed sensor set and fuse different methods to obtain a fast and accurate evaluation result is an important problem to be addressed deeply. In the paper, a multi-agent fusion and coordination system is presented to deal with the damage identification for the strain distribution and joint failure in the large structure. Firstly, the monitoring system is adopted to distributedly monitor two kinds of damages, and it self-judges whether the static load happens in the monitored sub-region, and focuses on the static load on the sub-region boundary to obtain the sensor network information with blackboard model. Then, the improved contract net protocol is used to dynamically distribute the damage evaluation module for monitoring two kinds of damage uninterruptedly. Lastly, a reliable assessment for the whole structure is given by combing various heterogeneous classifiers strengths with voting-based fusion. The proposed multi-agent system is illustrated through a large aerospace aluminum plate structure experiment. The result shows that the method can significantly improve the monitoring performance for the large-scale structure.     

基于社会认知算法的软件可靠性分配问题研究

针对软件可靠性分配问题中求解全局最优解的困难,在保证系统开发费用最低的前提条件下,将可靠性指标分配到每个模块中,并利用一种新的智能优化算法——社会认知算法来搜索模型的最优解。实验结果表明了社会认知算法在求解软件可靠性分配问题中的有效性。     

基于LabVIEW的虚拟仪器技术在结构健康监测中的应用

基于虚拟仪器技术构建新的结构健康监测系统,介绍了利用LabVIEW图形化编程语言开发设计结构健康监测系统的设计思想、结构组成、实现方法和功能.与传统结构健康监测系统相比,基于虚拟仪器的结构健康监测系统,具有可操作性强、通用性好、性价比高、功能强大、快捷方便等特点.并且能够实现数据的自动采集和在线实时监测,可以对数据进行多种方式的分析和处理,在工程实际中具有广阔的应用前景.     

A coordinate descent based method for geometry optimization of trusses

The main objective of the structure optimization is to reduce the manufacturing cost of the structure. However, economical design should not deviate from engineering restrictions and laws. Based on this concept, various methods have been invented to optimize structures. In this research, some variations in one of the very simple and primary methods called “coordinate descent” or “successive coordinate search” is used for geometry optimization of the trusses. In order to increase the optimization speed and decrease the solution time of the problem, fast matrix analysis methods has been employed leading to reduction of the time required for calculating of the objective function. Furthermore, an optimized solution seeking algorithm has been introduced. In this algorithm, some factors have been defined by which the relation between the optimization time and these factors have been calculated, both experimentally and mathematically and the appropriate values of these factors are obtained to reduce the optimization time. Moreover, the effect of increasing the accuracy of the optimum solution on the number of analyses has been studied. Analysis of the presented method shows that regardless of its simplicity, it can be utilized as a fast method for optimizing variety of structures.     

基于期权思想的产业投资结构的控制与优化

运用期权的观点和方法研究产业投资问题具有重要的现实意义，在衡量投资机会价值的基础上，提出一和中产业增量投资期权决策思路，基于期权的观点建立了与项目投资决策类似的产业投资决策期权模型，提出一种控制与优化产业投资结构的新思路，具有一定的实际应用价值。     

A survey on nature-inspired optimization algorithms with fuzzy logic for dynamic parameter adaptation

Metaheuristic optimization algorithms have become a popular choice for solving complex problems which are otherwise difficult to solve by traditional methods. However, these methods have the problem of the parameter adaptation and many researchers have proposed modifications using fuzzy logic to solve this problem and obtain better results than the original methods. In this study a comprehensive review is made of the optimization techniques in which fuzzy logic is used to dynamically adapt some important parameters in these methods. In this paper, the survey mainly covers the optimization methods of Particle Swarm Optimization (PSO), Gravitational Search Algorithm (GSA), and Ant Colony Optimization (ACO), which in the last years have been used with fuzzy logic to improve the performance of the optimization methods.     

基于聚类分析的微粒群算法

在对基本PSO算法进行分析的基础上,针对PSO算法中的早熟收敛问题,提出了一种基于聚类分析的PSO算法（CPSO）。CPSO算法保证了微粒种群的多样性,使微粒能够有效地进行全局搜索。并证明了它依概率收敛于全局最优解。最后以典型的基准优化问题进行了仿真实验,验证了CPSO的有效性。     

基于设计结构矩阵的辅助优化系统

传统结构优化建模方法对设计人员的能力要求较高,而现有辅助优化建模工具的通用性不强,导致复杂工程优化问题的模型建立十分困难,因此提出一种通用性较强的辅助优化建模方法.该方法将设计结构矩阵(Design Structure Matrix,DSM)思想引入优化模型的建立过程中,利用DSM结构形式和算法的优点方便有效地从复杂工程问题中提取优化模型并给出合理的优化流程.基于Excel的VBA语言开发辅助优化建模工具,快速准确地提取优化模型,并通过与优化软件Isight的接口程序自动将参与优化设计的模块映射成合理的优化流程图.采用燃气轮机支架结构的优化设计问题验证该辅助优化建模工具,并取得良好效果.     

A robust method for measuring trabecular bone orientation anisotropy at in vivo resolution using tensor scale

Trabecular bone (TB) is a network of interconnected struts and plates that constantly remodels to adapt dynamically to the stresses to which it is subjected in such a manner that the trabeculae are oriented along the major stress lines (Wolff's Law). Next to bone density, TB anisotropy has been found to be one of the most significant determinants of the bone's biomechanical behavior. Typically, orientational anisotropy of TB networks is expressed in terms of the fabric tensor, obtained by measuring the mean intercept length between structure elements along test lines. This method, however, can provide only a global statistical average of TB orientation anisotropy and, in general, requires a large sampling volume. Here, we present a new method, based on the recently conceived notion of “tensor scale”, which provides regional information of TB orientation anisotropy. Regional structure is represented by local best fit ellipsoid (ellipse in 2D) and the structural orientation is determined from the eigenvectors along the semi-axes. The method is found to be remarkably robust over a wide range of resolution regimes and image rotation as shown with micro-CT images from specimens of the human distal radius, the latter showing the characteristic differences in structural anisotropy for transverse and longitudinal sections. Finally, the method's applicability to in vivo MR imaging is demonstrated with data from the distal tibia.     

基于改进PSO算法的嵌套环式微陀螺结构优化设计

摘要：改变嵌套环陀螺的结构设计会引起陀螺性能发生很大的改变,但由于其结构复杂,参数众多,导致陀螺在仿真过程中计算量过大,难以探索陀螺多参数变量对陀螺性能的影响规律,针对这一问题提出了一种基于改进PSO算法的嵌套环陀螺结构优化设计方法。该方法在传统PSO算法寻优的基础上,引入极值扰动来避免算法陷入局部极值,并针对嵌套环陀螺进行了一定的条件约束,解决了多参数在总和固定情况下的优化问题。改进后的优化算法以机械热噪声为目标函数,在波音设计的陀螺模型基础上对其间隙分布进行了优化实验,并与未优化前进行了性能对比,结果表明,改进后的优化算法使嵌套环陀螺性能显著提高,结构优化设计更加高效简洁,适用于嵌套环陀螺进行各种多参数的优化问题。     

基于粒子群算法的数据库查询优化

查询优化是数据库系统设计和实现所采用的一项重要技术,也是影响数据库系统性能的一个重要因素.本文把一种新的演化计算模型＂粒子群算法＂引入查询优化模型中来,在查询策略的状态空间上构造了粒子群算法的一个原型,利用粒子群算法对连接操作进行优化.     

Structural analysis based sensor measurement fault diagnosis in cement industries

This investigation presents a fault diagnosis methodology for detecting sensor faults in cement industries pyro processing section. It works in three steps: (a) modelling, (b) analysis, and (c) validation. In the modelling, the actual data from the cement pyro processing is used to do a correlation analysis between output and input variables. The structural model is obtained from the correlation tests. During the analysis phase the Structural analysis Tool (SaTool) is used to detect the detectability and isolability of the faults. The results of the structural analysis are validated in a cement industry using residual analysis performed using structural sensor model and real-time measurements. The main advantages of this fault diagnosis technique are: (a) it requires only correlation analysis to obtain the structural model without a detailed physical model as in other methods, (b) conclusions regarding detectability and isolability can be easily drawn during the analysis stage itself, and (c) the method is simple compared to the model-based, and data-history based methods. The effectiveness of the proposed method is illustrated using data from cement pyro processing plant and its performance is compared with model based approaches for four different types of sensor faults: (1) bias, (2) drift, (3) stuck, and (4) measurement failures. Our results demonstrate that the structural method is able to detect the sensor faults even in the presence of noisy information, and its performance is comparable with that of model based approaches without employing a physical model.     

基于聚类分析的随机微粒群算法

在对一种保证全局收敛的微粒群算法——随机PSO算法（SPSO）进行分析的基础上,提出了一种基于聚类分析的随机微粒群算法（CSPSO）。CSPSO算法保证了种群的多样性,使微粒能够有效地进行全局搜索。并证明了它依概率收敛于全局最优解。最后以典型的复杂基准优化问题进行了仿真实验,验证了CSPSO的有效性。     

基于群算法的过程参量聚类研究

针对复杂过程的参量聚类问题,提出一种基于粒子群优化算法的聚类方法,阐述了聚类算法的基本思路。通过对过程煅烧温度和煅烧转速二维数据的聚类仿真研究,证明该算法在类似过程参量聚类中的实用性能。对粒子群优化算法的聚类特性及参数设置进行了详细的分析,并将其与前期人工免疫聚类结果进行对比,提出了算法的改进方案。