基于Hopfield神经网络的结构优化算法

利用Hopfield神经网络与增广拉格朗日乘子法相结合来求解非线性约束的结构优化问题。针对神经网络模型容易陷入局部极小解的缺点,网络引入了模拟退火算法,提高了网络全局寻优能力,得到了较好的优化结果,本文详述了算法的步骤,编制了该算法的计算程序,最后通过两个实例证明该算法的可行性和有效性。     

项目资源约束下工期最短一资源均衡优化算法

网络计划的时间一资源优化安排是确保网络计划实现和获得成效的关键,在网络计划的工期内,如果资源的使用存在约束,那么任何时段对资源的需求量都不应该超过部门所能提供的最大值,并且对工期的影响应尽可能降低到最小化,同时资源的分配在各个时段要尽可能地均衡。在这种情形下,通过采用启发式算法和线性规划的方法分别对网络计划技术中“资源有限-工期最短”和“工期固定一资源均衡”两类问题实现优化,最终实现这两个目标的共同优化,并通过一个实例验证算法的适用性。     

Joint power distribution and charging network design for electrified mobility with user equilibrium decisions

Rapid adoption of electric vehicles (EVs) requires the development of a highly flexible charging network. The design and management of the charging infrastructure for EV-dominated transportation systems are intertwined with power grid operations both economically and technically. High penetration of EVs in the future can increase the charging loads and cause a wide range of operational issues in power distribution networks (PDNs). This paper aims to design an EV charging network with an embedded PDN layout to account for energy dispatch and underlying traffic flows in urban transportation networks supporting electric mobility in the near future. A mixed-integer bilevel model is proposed with the EV charging facility location and PDN energy decisions in the upper level and user equilibrium traffic assignment in the lower level considering an uncertain charging demand. The objective is to minimize the cost of PDN operations, charging facility deployments, and transportation. The proposed problem is solved using a column and constraint generation (C&CG ) algorithm, while a macroscopic fundamental diagram concept is implemented to estimate the arc travel times. The methodology is applied to a hypothetical and two real-world case study networks, and the solutions are compared to a Benders decomposition benchmark. The east-coast analysis results indicate a 77.3% reduction in the computational time. Additionally, the benchmark technique obtains an optimality gap of 1.15%, while the C&CG algorithm yields a 0.61% gap. The numerical experiments show the robustness of the proposed methodology. Besides, a series of sensitivity analyses has been conducted to study the impact of input parameters on the proposed methodology and draw managerial insights.     

交通网络平衡配流模型算法研究

交通网络配流问题是将实测或预测的交通分布量按照特定的出行规则分配加载至具体的道路网中,并根据相应算法求解得到各道路路段与交叉口节点的交通流量。首先介绍了有关交通配流的基本方法及性质,总结了常用的平衡及非平衡交通配流模型。考虑到平衡模型求解困难且算法运算时间长,将非平衡配流模型解法运用到平衡配流中去,以寻求复杂平衡问题的高效解法。     

环境目标下城市交通综合网络设计的优化模型及求解算法

机动车尾气排放因子(emission factor)、路段行驶时间和交叉口等待时间等都是影响城市交通尾气总排放量的重要因素。而城市交通网络中路段通行能力的改善或者交叉口信号配时方案的调整都会直接影响机动车尾气排放因子和交通出行时间的变化,从而影响城市交通尾气总排放量的大小。为此,首先根据机动车在路段上的行驶状况,引入两个与出行时间关联的尾气排放因子,即路段正常行驶时的尾气排放因子和交叉口排队等待时的尾气排放因子,进而给出适用于城市交通网络设计问题的尾气总排放量计算公式;然后用双层规划方法综合优化信号灯配时方案和道路能力改善方案,以达到最大程度地降低交通尾气总排放量的目的。基于粒子群优化算法,设计了一个求解该双层模型的全局优化算法,该算法操作简单,易于实现,并用一个简单算例验证了本文模型与算法的有效性。     

基于用户聚类的图书推荐算法设计与实现

个性化推荐算法中一直存在新用户的冷启动问题,文章通过引入ID3算法来预测、分析新用户的类别选择。首先,根据实验数据特征对ID3算法加以改进;其次,根据分析数据表中各字段的属性确定试验参数;最后,得出实验结果。     

Producer incentives in electricity markets with green quotas and tradable certificates

We study both intended and unintended consequences of cost reductions by green producers in a competitive electricity market operated under a green quota enforced via a green certificate system. We show that green producers may not have an incentive to exploit the full cost reduction potential of their technology and can in general be expected to engage in strategic cost padding. We propose a method of incentivizing RE producers to exploit the full cost reduction potential of the green technology. The method allows for strategic cost padding, but only at the expense of profit reducing changes in the RE quota.     

成年小鼠心脏单个细胞悬液的制备及流式细胞检测

目的:制备成年小鼠心脏单细胞悬液,测定心肌缺血再灌注损伤(reperfusion injury,RI)小鼠心肌中白细胞的分布情况。方法:选取10~12周龄SPF级雄性C57BL/6小鼠15只,按照随机方法将其分为假手术组5只(模型制备成功5只)和RI 24 h组10只(模型制备成功7只)。RI 24 h组小鼠心脏缺血30 min后,于再灌注24 h后摘取小鼠心脏,配置心脏消化液,冲洗剪碎进行消化,经过滤离心收集心脏细胞,行流式细胞检测,以CD45标记白细胞,并进一步行CD11c标记树突状细胞及Ly6C标记单核细胞。比较两组CD45阳性细胞比例及CD11c、Ly6C标记的细胞占CD45阳性细胞比例;比较两组各细胞在总心肌细胞中的比例。结果:每只小鼠心脏制备所得的单个细胞悬液行细胞计数为(1~2)×10~6个。RI 24 h组CD45阳性细胞占心肌细胞比例高于假手术组(P<0.05);RI 24 h组CD11c~+Ly6C~+树突状细胞占CD45阳性细胞的比例高于假手术组(P<0.05)。RI 24 h组CD11c标记的树突状细胞及Ly6C标记的单核细胞等各亚群细胞在总心肌细胞中的比例均高于假手术组(P<0.05)。结论:成年小鼠心脏细胞的单细胞悬液可以通过切碎和消化制备,可用单细胞悬液流式细胞仪检测RI心肌白细胞、树突状细胞和单核细胞的显著变化。本研究为小鼠心脏白细胞的详细分析提供了一种可行的方法。     

An equilibrium network design model with a social cost function for multimodal networks

In this paper, we present a comprehensive investment planning model and its solution approach. The model takes a bilevel programming form and allows a variety of effects of the investments incorporated. The model is characterized by its ability to address the total social costs occurring in transportation networks and to estimate the equilibrium link volumes in multimodal networks. Two solution algorithms were proposed. Both algorithms handle the discrete optimization problem by exploiting the strings of binary digits of integer variables. In an illustrative example, we performed network design analyses for three scenarios in which 25, 50, and 75% of the total required capital is available. By applying the two solution algorithms to the example problem, the optimal network alternative for each scenario was found. If a cost/benefit analysis is coupled with the proposed model, the optimal investments and the optimal network configuration will be determined simultaneously.

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Evaluation of user interaction with daylighting simulation in a tangible user interface

We present a study of a tangible user interface for design and simulation applied to architectural daylighting analysis. This tool provides an intuitive way for architects and future occupants of a building to quickly construct physical models and interactively view in them a projected simulation of resulting daylighting.A user study was conducted of both architecture students and non-architects in a set of analysis and design exercises. The study investigates the effectiveness of this interface as an educational tool, the precision and accuracy of the constructed physical models, and its effectiveness for creative design exploration. The four part study investigates users' intuitions about daylighting and their interaction with the tangible user interface for analysis of an existing space. These exercises revealed and corrected misconceptions in many of the participants' intuitions about daylighting, and overall the participants praised the ease-of-use of the tool and expressed interest in this simulation tool for daylighting analysis in architectural design.     

卷积神经网络优化算法研究

为了解决卷积神经网络结构复杂,样本训练神经网络时间过长的问题,本文提出了采用分数阶理论优化卷积神经网络中的节点函数,使Sigmoid函数的收敛速度加快,在不影响卷积神经网络进行音频识别的正确率的前提下,减少了训练所需时间,达到提高整个神经网络的训练效率的目的。实验结果表明,在保证正确率的前提下该方法有效的减少了训练所花的时间,并可广泛应用于虚拟人运动控制系统中。     

基于QOS的Mesh网络调度算法

为了实现具有QOS约束的Mesh网络任务调度,提出了一种满足QOS需求的Mesh网络调度方法。首先描述了Mesh网络的QOS约束并给出了数据包的调度方法。然后,在业务调度上提出了2层的调度方法,即根据业务优先级对队列进行调度,然后对节点根据等待时间和任务执行时间设定优先级,从而实现任务调度。仿真实验表明:文中方法能有效地实现Mesh网络任务调度,与其它方法相比,具有较小的网络延迟和较大的优越性。