IGCC蒸汽系统综合优化的研究

本文基于总能系统概念，把能的梯级利用原理与超结构等方法有机地结合起来，提出ＩＧＣＣ蒸汽系统流程与参数综合优化新思路和新方法。并对大型 ４００ ＭＷ级ＩＧＣＣ电站系统进行模块化建模和模拟分析，总结和揭示了ＩＧＣＣ蒸汽系统综合优化规律，得出若干有实用参考价值的结论。     

燃气轮机总能系统模拟优化的联立模块算法

本文推出的总能系统模拟分析联立模块新算法结合了序贯模块法和联立方程法的优点、缓解了它们的缺点、提出的两级三类模型建模思想，既能充分发挥联立模块法的优点，又能较好反映系统复杂的流体网络特性。本文构思了求解过程主要手段与技巧：初植获取，方程组降维，求解方法与步骤。实例研究表明所开拓的新算法是可行、实用的，对复杂系统模拟分析时优势明显．     

DNA超分子水凝胶的粗粒化建模与模拟

DNA超分子水凝胶在生物、医学领域具有广阔的应用前景,基于计算模拟技术研究其分子结构与其宏观性能关系具有重要意义.归因于其复杂的结构和较大的相关时间空间尺度,目前针对DNA水凝胶的分子建模与模拟研究比较缺乏.本文建立了一种DNA水凝胶的粗粒化模型,采用分子动力学模拟的方法针对一种模块化纯DNA水凝胶进行了研究.模拟结果表明其凝胶态介观结构为多孔海绵状,其交联度与水凝胶的浓度成正相关,并得出了其转变温度的范围等.模拟结果与相关实验定性或半定量符合,表明该模型可能用于该模块化DNA水凝胶等类似系统的结构功能关系研究.     

模拟法在物理实验中的应用

模拟法指的是以相似理论为基础，不直接研究自然现象或过程的本身，而用与这些自然现象或过程相似的模型来进行研究的一种方法．当前物理实验中的模拟基本上可分为以下二种类型：(1)物理模拟．物理模拟就是指两个不同本质的物理现象或过程，当可用同一个数学方程来描述，就可用其物理现象或过程来模拟另一物理现象或过程．例如，静电场的电位与电流场的电位具有相同的数学表达式，故常用稳恒电流场模拟静电场．(2)计算机模拟(数学模拟)．本质上是对某物理现象或过程建立数学模型，再借助计算机技术来模拟物理实验中所发生的物理过程的方法．     

综合非语境因素的语音数据分类与声学建模研究

分别采用基于数据聚类和基于先验知识的两种研究方法,深入探讨了性别、口音、语速、信道等非语境因素对语音数据分类与建模的影响。为了综合考虑语境、非语境因素在统一框架下建模的问题,采用非语境因素扩展决策树方法。而对于这种方法生成的多套非语境因素相关的高精度声学模型,提出一种依据最大似然准则,动态组合生成测试人相关声学模型的算法。这种方法可以使系统相对误识率平均降低8％-10％。实验结果说明为非语境因素分类建模可以提高声学模型的建模能力,而且模型组合算法可以有效解决统一建模所带来的模型选择问题。     

光机靶室钢混结构基于动刚度等效的简化建模

钢混结构分离式有限元建模方法由于考虑了钢筋的实际分布，其计算精度较高，但建模过程复杂繁琐。开展了基于动刚度等效的钢混结构简化建模研究，该方法将钢筋和混凝土考虑为一种等效材料。研究中首先以典型钢混组合结构为例，以等效模型与分离式模型的模态特性等效为目标，建立了分部件的动刚度等效模型，然后将各部件等效模型组合成整体结构等效模型，数值仿真结果显示在相同载荷作用下，整体参考模型与整体等效模型的响应分布非常接近，而等效模型的规模远小于参考模型，说明了该等效建模方式的有效性。进一步将该等效建模方法应用于神光Ⅲ主机靶室钢混结构的动力学分析中，并计算了该巨型光机结构等效模型在实测基础加速度激励下的随机振动响应，靶球上各方向的响应实测结果与计算结果较为吻合。所采用的动刚度等效建模方法可应用在巨型光机结构动力学稳定性的进一步研究中。     

干贝水分检测的建模及分级方法

高光谱成像已被应用于建立干贝水分含量预测模型，其模型性能受样本划分方法及建模方法影响。样本划分方法决定着所选样本是否具有代表性，而建模方法决定着如何利用样本建立模型，但样本划分方法与建模方法的内在联系却鲜有研究报道。在方法优选上，将样本划分方法与建模方法进行组合，探究不同方法组合对干贝水分含量预测模型性能的影响，对干贝水分检测建模及分级方法的优选具有重要意义，同时也能为其他样本的光谱建模提供参考。采集380～1 030 nm波段下270个干贝样本的高光谱图像，提取干贝样本的光谱数据，通过RS，KS，SPXY和CG四种常用的方法划分样本，并以PLSR和LS-SVM两种常用的建模方法建立多个干贝水分含量预测模型，计算和比较各模型的性能指标。结果表明: PLSR模型使用RS法划分干贝水分含量样本最为适宜(其RPD为4.079 6)，LS-SVM模型使用SPXY划分法最为适宜(其RPD为4.175 6)，划分样本方法的优劣与建模方法有关，其优选需要结合特定的建模方法进行。在常用的四种样本划分方法和两种建模方法中，采用SPXY法划分干贝水分含量样本并结合LS-SVM法建模的效果和精度最好。     

锅炉汽水系统动态过程仿真

本文采用模块化建模的方法,建立了电站锅炉系统中汽温系统、蒸发系统较为精细的动态数学模型,针对某20万千瓦机组,细致地模拟了几种情况下锅炉汽水侧多个点的基本参数的变化过程,并对结果进行了分析,有助于判断汽水侧动态过程对锅炉运行的影响。     

虚拟样机中电缆的建模与仿真

电缆的建模与仿真在产品开发中具有重要的应用价值，也是目前虚拟样机技术急需解决的难题。针对电缆属于柔性件的特点，提出了一种基于几何建模和物理建模的综合建模与仿真方法，其基本思路是：几何建模一长度估算一物理建模一行为仿真，如图l所示。几何建模以电缆连接列表为依据、以产品结构模型为空间约束、按照电缆布线规范，利用人机交互方式进行电缆卡箍位置规划和电缆路径规划，进而建立电缆几何模型。长度估算利用空间积分方法对几何模型进行积分得到电缆长度。物理建模将电缆几何模型离散成多个质点单元，各质点单元间通过弹簧连接，弹簧刚度和质点质量根据电缆材料和长度确定，在此基础上建立“质点一弹簧系统”的力学控制方程。行为仿真根据“质点一弹簧系统”的力学控制方程模拟电缆真实形状及插接过程。     

混合非机动车流的多值元胞机模型模拟研究

采用多值元胞机模型对混合非机动车流进行了建模模拟研究. 混合非机动车流在我国城市交通中主要表现为三轮车和自行车的混合. 针对三轮车和自行车实际尺寸的差异，设定自行车占据一个单位空间，三轮车占据两个单位空间. 模拟结果显示：在三轮车与慢速自行车混合的系统中，三轮车比例和三轮车先行概率不会对系统流量造成影响，而三轮车先行概率只会影响到车辆的平均速度；在三轮车与快速自行车混合的系统中，确定性条件下在自由流区域和堵塞流区域都会出现多分支现象，快速自行车具有慢化概率时多分支现象消失. 关键词： 混合非机动车流 元胞自动机 多分支     

Modeling wireless sensor networks using random graph theory

A critical issue in wireless sensor networks (WSNs) is represented by limited availability of energy within network nodes. Therefore, making good use of energy is necessary in modeling sensor networks. In this paper we proposed a new model of WSNs on a two-dimensional plane using site percolation model, a kind of random graph in which edges are formed only between neighbouring nodes. Then we investigated WSNs connectivity and energy consumption at percolation threshold when a so-called phase transition phenomena happen. Furthermore, we proposed an algorithm to improve the model; as a result the lifetime of networks is prolonged. We analyzed the energy consumption with Markov process and applied these results to simulation.     

基于最大熵估计Alpha谱缩放与平移量的温度与发射率分离算法

在热红外波段, 为了使温度与发射率分离过程不依赖数据库提供的经验信息, 并且实现更高的反演精度和更快的计算速度, 研究了一种新的温度与发射率分离算法. 首先, 在维恩近似原理的基础上, 求解了Alpha谱分布, 并利用Alpha谱描述光谱发射率的形状信息. 其次, 改进了最大熵温度与发射率分离算法: 应用最大熵估计模型对Alpha谱缩放与平移量进行估计, 减少了待估计参数的数量, 大幅简化了求解过程. 最后, 进行了算法的数值仿真实验: 求解了典型地物目标的温度与光谱发射率, 并且分析了算法对系统噪声的鲁棒性. 仿真数据表明: 发射率估计的最大RMSE为0.017, 温度估计的最大绝对误差的绝对值为0.62 K; 对系统添加测量信噪比为11的高斯白噪声, 发射率估计的相对RMSE为2.67%, 温度估计的相对误差为1.26%. 结果表明: 本文所述算法求解精度高, 计算速度快, 具备良好的鲁棒性.     

平行磨削非轴对称非球面光学元件表面形貌

结合砂轮表面仿真及磨削过程的运动学仿真获得工件表面轮廓、形貌和粗糙度预计,可以作为磨削过程中的理论依据,是精密磨削加工技术中主要的研究内容之一。平行磨削技术是加工非轴对称非球面光学元件的重要手段,而相关的仿真过程报道还很少。提出一种基于平行磨削的精密磨削加工非球面表面生成的仿真方法,该方法主要包含使用高斯方法生成具有不同统计学特征的随机砂轮表面形貌,建立单磨粒运动轨迹方程和圆弧砂轮细分后与工件表面点接触的运动关系,据此给出平行磨削加工表面生成的数值算法,并对不同加工参数下的工件表面形貌进行仿真。仿真结果和测量结果的一致性验证了所给算法的正确性和有效性     

Efficient Network Dismantling via Node Explosive Percolation

The network dismantling problem asks the minimum separate node set of a graph whose removal will break the graph into connected components with the size not larger than the one percentage of the original graph.This problem has attracted much attention recently and a lot of algorithms have been proposed. However, most of the network dismantling algorithms mainly focus on which nodes are included in the minimum separate set but overlook how to order them for removal, which will lead to low general efficiency during the dismantling process. In this paper,we reformulate the network dismantling problem by taking the order of nodes' removal into consideration. An efficient dismantling sequence will break the network quickly during the dismantling processes. We take the belief-propagation guided decimation(BPD) dismantling algorithm, a state-of-the-art algorithm, as an example, and employ the node explosive percolation(NEP) algorithm to reorder the early part of the dismantling sequence given by the BPD. The proposed method is denoted as the NEP-BPD algorithm(NBA) here. The numerical results on Erd¨os-R′enyi graphs,random-regular graphs, scale-free graphs, and some real networks show the high general efficiency of NBA during the entire dismantling process. In addition, numerical computations on random graph ensembles with the size from 2~(10) to2~(19) exhibit that the NBA is in the same complexity class with the BPD algorithm. It is clear that the NEP method we used to improve the general efficiency could also be applied to other dismantling algorithms, such as Min-Sum algorithm,equal graph partitioning algorithm and so on.     

Discrete-time modeling of woodwind instrument bores using wave variables

A method for simulation of acoustical bores, useful in the context of sound synthesis by physical modeling of woodwind instruments, is presented. As with previously developed methods, such as digital waveguide modeling (DWM) [Smith, Comput. Music J. 16, 74-91 (1992)] and the multi convolution algorithm (MCA) [Martinez et al., J. Acoust. Soc. Am. 84, 1620-1627 (1988)], the approach is based on a one-dimensional model of wave propagation in the bore. Both the DWM method and the MCA explicitly compute the transmission and reflection of wave variables that represent actual traveling pressure waves. The method presented in this report, the wave digital modeling (WDM) method, avoids the typical limitations associated with these methods by using a more general definition of the wave variables. An efficient and spatially modular discrete-time model is constructed from the digital representations of elemental bore units such as cylindrical sections, conical sections, and toneholes. Frequency-dependent phenomena, such as boundary losses, are approximated with digital filters. The stability of a simulation of a complete acoustic bore is investigated empirically. Results of the simulation of a full clarinet show that a very good concordance with classic transmission-line theory is obtained.     

基于Petri网与萤火虫算法的任务分配可视化建模

为了解决民用飞机故障诊断中任务分配问题,提出了使用新型离散萤火虫算法对任务分配问题进行研究,并在此基础上,使用Petri网进行可视化建模与仿真。新型的萤火虫算法离散方法,使得原本应用于连续问题的萤火虫算法适用于任务分配问题,这样使Petri网建模的复杂性降低,更利于建模。最后,对一实例进行分析并进行可视化建模与仿真,动态的仿真过程及最终结果验证了模型的可行性及算法的正确性。因此,使用该方法可有效地降低建模的复杂性,提高任务分配的效率,同时能够应用于协同可视化诊断平台中的任务分配模块。     

A Kalman filter algorithm based on exact modeling for FOG GPS/SINS integration

The Kalman filter is widely applied in fiber optic gyro (FOG) inertial integrated navigation system. To solve the problem of hard acquirement of Kalman filter parameters, a novel algorithm for FOG GPS/SINS integration navigation based on exact modeling is proposed in this paper. The models of inertial sensors using Allan variance analysis are established in proposed algorithm and the precise Kalman filter model is obtained based on the correspondence between Allan variance coefficients and inertial sensors parameters. The simulation and experimental results show that Kalman filter parameters can be obtained for GPS/SINS integrated navigation system precisely and efficiently based on Allan variance modeling method, and the algorithm has reference value for theoretical perfection and engineering applications.     

Accurate and efficient algorithm for simulation of fringe projection system

Because of intrinsic drawbacks of existing algorithm for optical simulation: first, there is an accuracy problem, finite-precision machine arithmetic introduces error into line-surface intersection calculation. Second, these algorithms do not or partially consider process of shadow modeling. In this paper, we present an algorithm based on geometric analysis to simulate fringe projection system, a variable-step-iterative (VSI) algorithm is used to search line-surface intersection point, which can avoid many difficult problems. The proposed algorithm can accurately identify the shadow. Simulation results shows the reconstructed RMS errors obtained by our algorithm are far smaller than those obtained by previous reported algorithm. Simulation results validate our VSI algorithm can obtain more accurate results than many previous intersection point algorithms. Simulation results indicate our shadow modeling algorithm exceeds many existing shadow modeling algorithm, and is equivalent to shadow volumes algorithm, but our shadow algorithm runs faster than shadow volumes algorithm.