A globally convergent algorithm for transportation continuous network design problem

The continuous network design problem (CNDP) is characterized by a bilevel programming model, in which the upper level problem is generally to minimize the total system cost under limited expenditure, while at the lower level the network users make choices with regard to route conditions following the user equilibrium principle. In this paper, the bilevel programming model for CNDP is transformed into a single level convex programming problem by virtue of an optimal-value function tool and the relationship between System Optimum (SO) and User Equilibrium (UE). By exploring the inherent nature of the CNDP, the optimal-value function for the lower level user equilibrium problem is proved to be continuously differentiable and its derivative in link capacity enhancement can be obtained efficiently by implementing user equilibrium assignment subroutine. However, the reaction (or response) function between the upper and lower level problem is implicit and its gradient is difficult to obtain. Although, here we approximately express the gradient with the difference concept at each iteration, based on the method of successive averages (MSA), we propose a globally convergent algorithm to solve the single level convex programming problem. Comparing with widely used heuristic algorithms, such as sensitivity analysis based (SAB) method, the proposed algorithm needs not strong hypothesis conditions and complex computation for the inverse matrix. Finally, a numerical example is presented to compare the proposed method with some existing algorithms.     

混合催化剂合成水性环氧丙烯酸酯的研究

通过环氧丙烯酸树脂和双羟基化合物反应,获得具有亲水性链段的水性环氧丙烯酸酯。研究了催化剂用量和反应温度对转化率的影响,确定了以混合催化剂的最佳反应条件。采用FT-IR红外光谱对所合成的数值进行了表征,实验结果表明可以获得目的产物。     

Integrated Co-evolution Model of Land Use and Traffic Network Design

An integrated co-evolution model with the consideration of land use and traffic network design is proposed in this paper. In the suggested model, two kinds of economic agents are considered. On the one hand, the government makes the investment decision for the traffic network improvement based on the current traffic condition under the limited budget. On the other hand, households and companies will choose their locations according to the attraction of each traffic zone related to the road network accessibility and the housing price. Therefore, the land use is indicated by the population and employment distributions through the evolution process. Besides, the improvement of road capacity is modeled by a general bi-level programming of traffic network design. Simulation experiments show that the city will be more efficient and will have higher average accessibility for employment and population in the evolution process.     

基于 NI CompactRIO 的多通道磁场采集系统的设计与实现

针对磁法勘探、地磁导航等不同技术领域的地磁测量需求,提出了一种多传感器模块化采集方案,构建了基于NI CompactRIO的多通道磁场采集系统.系统整合了光泵磁力仪,磁通门磁力仪,惯性导航模块以及GPS模块,可满足不同情况下的实验需求.为了解决多传感器组件同时采集时数据无法同步的问题,提出了基于GPS的同步授时技术以保证数据的有效性.利用插值计数器实现了数字倒数插值测频法,在铯光泵磁力仪有效输出范围内,磁测分辨率优于0.006 nT.在吉林大学电磁屏蔽室中,对系统噪声水平进行了评估,评估结果表明采集系统的PSD为7 pT/Hz@1 Hz,符合设计要求.最后在长春南湖和内蒙古桃合木苏木两个实验场地应用采集系统,验证了系统在野外恶劣环境下能够稳定工作,并高效地完成采集任务.     

Population-driven Urban Road Evolution Dynamic Model

In this paper, we propose a road evolution model by considering the interaction between population distribution and urban road network. In the model, new roads need to be constructed when new zones are built, and existing zones with higher population density have higher probability to connect with new roads. The relative neighborhood graph and a Fermat-Weber location problem are introduced as the connection mechanism to capture the characteristics of road evolution. The simulation experiment is conducted to demonstrate the effects of population on road evolution. Moreover, the topological attributes for the urban road network are evaluated using degree distribution, betweenness centrality, coverage, circuitness and treeness in the experiment. Simulation results show that the distribution of population in the city has a significant influence on the shape of road network, leading to a growing heterogeneous topology.     

大厚度临氢Cr-Mo钢在辊式淬火线生产工艺的开发与应用

根据舞钢300 mm厚板辊式淬火线工艺特点,结合以往采用淬火槽生产大厚度临氢Cr-Mo钢的经验及其性能要求,对钢板成分设计和正火加速冷却过程关键工艺参数进行研究,确定了大厚度临氢Cr-Mo钢板在舞钢300 mm厚板淬火线合适的正火加速冷却工艺,成功实现了大厚度临氢Cr-Mo钢板的批量生产.检验结果表明:由300 mm厚板辊式淬火线生产的大厚度临氢Cr-Mo钢板,力学性能稳定,完全满足严格的使用要求,同时板型控制效果良好,在国内临氢压力容器制造领域得到广泛应用.     

有压隧洞围岩最小覆盖层厚度弹塑性力学分析

水工隧洞的最小覆盖层厚度受到多方面因素的影响,如何确定最小覆盖层厚度是水工隧洞设计中必须重视的关键点之一.针对传统的最小覆盖层厚度算法的不足,本文提出了基于采用弹塑性力学方法的优化算法.该优化算法综合考虑了黏聚力、内摩擦角、地质强度指标、施工扰动等因素的影响,得到的最小覆盖层厚度更加符合实际情况.根据水工隧洞运行期的受...     

电子束点焊熔池的液态金属冲刷效应作用规律

为了更深入地探究电子束焊接过程中的机理问题,基于对电子束点焊熔池中液态金属冲刷效应的理论分析,利用边界层理论对该效应进行数学建模.使用有限体积法数值软件Fluent,对20 mm厚的2219铝合金电子束点焊熔池的温度场和流场进行三维瞬态数值模拟,研究了液态金属冲刷效应对熔池的作用规律.模拟结果表明,液态金属冲刷效应会对熔池温度场、匙孔稳定性、熔池流场和固液界面形状与位置四个方面产生影响.模拟结果与试验结果吻合良好,验证了数学模型的合理性.     

太平煤矿副井井壁破裂注浆加固施工实践

分析了太平煤矿副井井壁破裂机理;在此基础上,确定了合理的注浆加固治理方案。在破裂井壁注浆加固施工中,选用中国矿业大学研制的改性脲醛浆液作为注浆材料,实现了对井壁的有效加固,封堵住了渗漏水,收到了较好的效果。     

Audio-visual sports highlights extraction using Coupled Hidden Markov Models

We present our studies on the application of Coupled Hidden Markov Models(CHMMs) to sports highlights extraction from broadcast video using both audio and video information. First, we generate audio labels using audio classification via Gaussian mixture models, and video labels using quantization of the average motion vector magnitudes. Then, we model sports highlights using discrete-observations CHMMs on audio and video labels classified from a large training set of broadcast sports highlights. Our experimental results on unseen golf and soccer content show that CHMMs outperform Hidden Markov Models(HMMs) trained on audio-only or video-only observations. Next, we study how the coupling between the two single-modality HMMs offers improvement on modelling capability by making refinements on the states of the models. We also show that the number of states optimized in this fashion also gives better classification results than other number of states. We conclude that CHMMs provide a promising tool for information fusion techniques in the sports domain for audio-visual event detection and analysis.