Cellular Automata-based Chloride Ion Diffusion Simulation of Concrete Bridges under Multi-factor Coupling Actions

In order to accurately simulate the diffusion of chloride ion in the existing concrete bridge and acquire the precise chloride ion concentration at given time, a cellular automata （CA）-based model is proposed. The process of chloride ion diffusion is analyzed by the CA-based method and a nonlinear solution of the Fick＇s second law is obtained. Considering the impact of various factors such as stress states, temporal and spatial variability of diffusion parameters and water-cement ratio on the process of chloride ion diffusion, the model of chloride ion diffusion under multi-factor coupling actions is presented. A chloride ion penetrating experiment reported in the literature is used to prove the effectiveness and reasonability of the present method, and a T-type beam is taken as an illustrative example to analyze the process of chloride ion diffusion in practical application. The results indicate that CA-based method can simulate the diffusion of chloride ion in the concrete structures with acceptable precision.

Multi-Agent Reinforcement Learning Algorithm Based on Action Prediction

Multl-agent reinforcement learning algorithms are studied. A prediction-based multi-agent reinforcement learning algorithm is presented for multl-robot cooperation task. The multi-robot cooperation experiment based on multi-agent inverted pendulum is made to test the efficency of the new algorithm, and the experiment results show that the new algorithm can achieve the cooperation strategy much faster than the primitive multiagent reinforcement learning algorithm.

基于Multi-Agent异步深度强化学习的居民住宅能耗在线优化调度研究

为促进居民用户柔性负荷高效参与需求响应,帮助用户从被动角色转变为主动角色,实现需求侧最大效益。该文在智能电网环境下,根据用电设备的特性,以概率论的角度对家电设备状态进行描述定义,基于异步深度强化学习(asynchronous deep reinforcement learning,ADRL)进行家庭能源管理系统调度的在线优化。学习过程采用异步优势演员–评判家(asynchronous advantage actor-critic,A3C)方法,联合用户历史用电设备运行状态的概率分布,通过多智能体利用CPU多线程功能同时执行多个动作的决策。该方法在包括光伏发电、电动汽车和居民住宅电器设备信息的某高维数据库上进行仿真验证。最后通过不同住宅情境下的优化决策效果对比分析可知,所提在线能耗调度策略可用于向电力用户提供实时反馈,以实现用户用电经济性目标。

多学科协作的I-PDCA模式在结直肠癌学科建设中的实践与思考

目的 探讨北京大学肿瘤医院结直肠癌学科建设中多学科协作模式及实施情况,为医院学科建设和创新管理提供借鉴。方法 本中心7年来将创新设计与传统PDCA管理方法相融合,针对医疗、科研、人才培养开展了五阶段I-PDCA新模式的多学科协作。结果 该模式弥补了传统PDCA四阶段模式缺乏创造力的弊端,促进了本院结直肠癌学科相关资源在多个维度的高效配置,在结直肠癌学科建设中发挥了重要作用。结论 结直肠癌多学科协作的I-PDCA模式有利于提升医疗服务、科研成果产出和人才培养水平,为学科未来发展提供助力。

Multi-features Based Approach for Moving Shadow Detection

In the video-based surveillance application, moving shadows can affect the correct localization and detection of moving objects. This paper aims to present a method for shadow detection and suppression used for moving visual object detection. The major novelty of the shadow suppression is the integration of several features including photometric invariant color feature, motion edge feature, and spatial feature etc. By modifying process for false shadow detected, the averaging detection rate of moving object reaches above 90% in the test of Hall-Monitor sequence.

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST)

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST, also called the Guo Shou Jing Telescope) is a special reflecting Schmidt telescope. LAMOST’s special design allows both a large aperture (effective aperture of 3.6 m–4.9 m) and a wide field of view (FOV) (5°). It has an innovative active reflecting Schmidt configuration which continuously changes the mirror’s surface that adjusts during the observation process and combines thin deformable mirror active optics with segmented active optics. Its primary mirror (6.67m×6.05 m) and active Schmidt mirror (5.74m×4.40 m) are both segmented, and composed of 37 and 24 hexagonal sub-mirrors respectively. By using a parallel controllable fiber positioning technique, the focal surface of 1.75 m in diameter can accommodate 4000 optical fibers. Also, LAMOST has 16 spectrographs with 32 CCD cameras. LAMOST will be the telescope with the highest rate of spectral acquisition. As a national large scientific project, the LAMOST project was formally proposed in 1996, and approved by the Chinese government in 1997. The construction started in 2001, was completed in 2008 and passed the official acceptance in June 2009. The LAMOST pilot survey was started in October 2011 and the spectroscopic survey will launch in September 2012. Up to now, LAMOST has released more than 480 000 spectra of objects. LAMOST will make an important contribution to the study of the large-scale structure of the Universe, structure and evolution of the Galaxy, and cross-identification of multiwaveband properties in celestial objects.

STUDY ON ANTIBACTERIAL ACTION OF 4-[P-ACETYLAMINO]BENZENESULFONAMIDOL SELENOMORPHOLINE BY MICROCALORIMETRY

Antibacterial action of 4-[p-acetylamino benzenesulfonamido] selenomorpholine (SeB) was studied by microcalorimetry with an LKB-2277 Bioactivity Moni-tor. It was found that SeB had the capacity to inhibit the metabolic growth of Escherichia coli. But in different sol-vent, the extent of inhibition is different. Removing the effect of solvent, we obtained the half-inhibition conce.ntra-tion(IC50) of SeB from the power-time curves. The value of IC50 of SeB was 1319μg ·mL-1.

台风登陆期间跨海大桥风-浪-流作用结构振动分析

台风登陆时,常诱发狂风、巨浪、风暴潮等自然灾害,威胁跨海大桥的安全。开展台风登陆期间跨海大桥风-浪-流多灾害作用随机振动分析对桥梁结构设计及安全运营有重要作用。首先,介绍台风登陆期间的风-浪-流多灾害数值模拟技术,利用台风混合风场模型驱动SWAN+ADCIRC波流耦合模型实现桥址海域台风期间的风、浪、潮、流模拟。然后,总结了风、浪、潮、流荷载的计算方法,其中风荷载采用了台风风谱,波浪荷载考虑台风波浪谱及各墩非一致激励。以某跨海公铁两用大桥为例,基于台风“艾利”期间的环境参数模拟结果,并借助有限元软件ANSYS开展跨海大桥多灾害作用振动分析。研究结果表明,长期响应的统计特征可利用每次10 min的30次短期随机时程分析结果均值作为代表值,桥梁短期动力响应极值服从广义极值分布;考虑风向、波向变化对桥梁随机振动分析结果影响显著。

A Comparative Study of Acute Hemodynamic Effects of Multi -site Cardiac Pacing in patients with cardiac function NYHA class ⅠtoⅡ without bundle branch block

Objective To compare the acute hemodynamic effects of five different pacing modes in patients with cardiac function NYHA class Ⅰ to Ⅱ without bundle branch block (BBB). Methods This study included 12 patients (SSS 7, Ⅲ°AVB 5) undergoing pacemaker implantation. Right ventricular apex (RVA), right ventricular outflow tract (RVOT), right ventricular bifocal (RV-Bi), left ventricular base (LVB) and bi -ventricular (Bi-Ⅴ) pacing at 60 -80 ppm were done in VVI mode prior to implantation of DDD pacemaker. The cardiac index (CI), mean pulmonary artery pressure (mPAP) and pulmonary capillary wedge pressure (PCWP) were measured with Swan - Ganz thermodilution catheter after 5 minutes of each pacing mode. Results (1) Comparing to pacing at RVA (CI: 2. 41± 0. 38 L/min per m2, PCWP: 16. 7 ±3.3 mmHg), the CI increased and the PCWP decreased significantly in pacing at RVOT(CI: 2. 63 ± 0.46, PCWP: 13. 8±2. 3), LVB(CI: 2. 78±0.52, PCWP: 14. 4±3.1), RV-Bi(CI: 2. 83±0.57, PCWP: 12. 8± 2. 5) and Bi -Ⅴ pacing (CI: 2. 94± 0.60, PCWP: 12. 7±2. 5), P < 0. 01, respectively. (2) The CI of RV-Bi and Bi-Ⅴ pacing was higher than that of RVOT and LVB pacing, the PCWP was lower, P < 0. 05, respectively. (3) There was no significant difference between RV - Bi pacing and Bi-Ⅴ pacing in CI and PCWP. Conclusion There is no significant difference between RV - Bi pacing and Bi -V pacing in the acute hemodynamic effects; however,dual - site pacing is much better than single site pacing in that aspect for patients with cardiac function NYHA class Ⅰ to Ⅱ without BBB. Among single site pacing, the RVOT and LVB pacing is better than RVA pacing in cardiac function.

基于语言-视觉对比学习的多模态视频行为识别方法

以对比语言-图像预训练(Contrastive language-image pre-training, CLIP)模型为基础,提出一种面向视频行为识别的多模态模型,该模型从视觉编码器的时序建模和行为类别语言描述的提示学习两个方面对CLIP模型进行拓展,可更好地学习多模态视频表达.具体地,在视觉编码器中设计虚拟帧交互模块(Virtual-frame interaction module, VIM),首先,由视频采样帧的类别分词做线性变换得到虚拟帧分词;然后,对其进行基于时序卷积和虚拟帧分词移位的时序建模操作,有效建模视频中的时空变化信息;最后,在语言分支上设计视觉强化提示模块(Visual-reinforcement prompt module,VPM),通过注意力机制融合视觉编码器末端输出的类别分词和视觉分词所带有的视觉信息来获得经过视觉信息强化的语言表达.在4个公开视频数据集上的全监督实验和2个视频数据集上的小样本、零样本实验结果,验证了该多模态模型的有效性和泛化性.

Research on A Master - slave Multi - microcomputers Control System for Hollow Spindle Fancy Yarn Spinning Machine

In this paper, a successfully studied and developed master - slave muld - microcomputers control system based on PC - BUS for hollow spindle fancy yarn spinning machine, mainly Its overall scheme, software and hardware construction, is introduced. Spinning experiments show that the system achieves satisfactory result. This system can solve the diftkultles of mechatronical fusion between domestic hollow splndk fancy yarn spuming muchine and its microcomputer control technology.

On the Representation of Multi-layer Woven Structure

A quantitative method is developed to identify the structures of multi-layer woven fabric in this study. Six structural parameters are selected to represent the fabric structure. With some design criteria for the reinforcement of textile composites, the relationships among the structural parameters are derived for different binding patterns of the fabric structure. The conditions, which meet the requirements of structural cell stability,are also discussed.

Computer-aided Pattern Design of Multi-bar Warp Knitted Fabrics

To meet the development trend of multi-bar warp knit-ting machine towards high-speed,advanced technologyand computer control and the requirements of variousproducts with small quantity,there are many researcheson the computer-aided pattern design of multi-barwarp knitted fabrics.In terms of the special propertiesof the computer-aided pattern design of multi-barwarp knitted fabrics,the Object Oriented Program(OOP)programming-Object Windows class Library(OWL)programming is selected.According to thecharacters of the OWL programming,various functionsare defined.Pattern design and technical parameters canbe output,which offers a great convenience for the fac-tory.

MODS： A Novel Metaheuristic of Deterministic Swapping for the Multi-Objective Optimization of Combinatorials Problems

This paper states a new metaheuristic based on Deterministic Finite Automata （DFA） for the multi - objective optimization of combinatorial problems. First, a new DFA named Multi - Objective Deterministic Finite Automata （MDFA） is defined. MDFA allows the representation of the feasible solutions space of combinatorial problems. Second, it is defined and implemented a metaheuritic based on MDFA theory. It is named Metaheuristic of Deterministic Swapping （MODS）. MODS is a local search strategy that works using a MDFA. Due to this, MODS never take into account unfeasible solutions. Hence, it is not necessary to verify the problem constraints for a new solution found. Lastly, MODS is tested using well know instances of the Bi-Objective Traveling Salesman Problem （TSP） from TSPLIB. Its results were compared with eight Ant Colony inspired algorithms and two Genetic algorithms taken from the specialized literature. The comparison was made using metrics such as Spacing, Generational Distance, Inverse Generational Distance and No-Dominated Generation Vectors. In every case, the MODS results on the metrics were always better and in some of those cases, the superiority was 100%.

CHINA: MAIN GEODETIC ACTIONS 1996-2000

This article reviews the progress made in geodetic work in China since the 1980s.In order to meet the needs of China’s economic and defense construction,and scientific and social development in the early 21th century,some main geodetic actions which should be completed before 2000 are proposed as follows.(1) Monitoring vertical crustal movements and conducting studies on its mechanism.Releveling of the second phase of the national first order leveling network.Computation of the vertical crustal movement.(2) Improvement of national space geodetic network.The main task is to lay down a national B-order GPS network and complete its data processing.(3) Refining of Chinese local gravity field on land and sea.The determination of Chinese local quasi geoid with higher than one meter accuracy.Application of

基于能量模型的LS-TSVM在人体动作识别中的应用

传统人体动作识别分类器对异常值比较敏感,容易受固有噪声影响,这会导致严重的类失衡问题,所以相似的人体行为可能存在很大类内差异。提出一种基于能量的最小二乘双分界面支持向量机(ELS-TSVM)的人体动作识别算法。ELS-TSVM是LS-TSVM的有效改进,采用两个超平面,每个超平面引进能量参数来减少噪声和异常值的影响。首先对于输入的视频使用梯度方向直方图特征和光流直方图特征识别人体动作;然后检测可能的兴趣点,生成时空特征后提取时空视觉词袋特征,通过构建一组视觉词袋来完成特征提取;最后,利用ELSTSVM完成分类。在Weizmann和Hollywood数据库上的实验验证了该算法的有效性及可靠性,相比其他几种较新方法,该算法更加高效精确,且大大减少了算法执行时间。

构建多元协作性社区治理机制解决集体行动困境——一个“产品-制度”分析(PIA)框架

在重新分析有关集体行动的各种经典描述和简化模型的基础上,首先从资源/资本、人性、产品和组织四个角度分别探讨了为当前学界研究所忽视的导致集体行动困境的各种深层原因;进而,在抽象社区和五个基本社会行动者的简单理论假设的前提下,从“产品-制度”分析(PIA)的角度系统探讨了解决集体行动的各种理想模型——四种自主治理模式(社区治理模型、俱乐部治理模型、优势群体治理模型和私有化治理模型)和四种他助治理模式(政府治理模型、企业治理模型、学者型治理模型和伦理道德型治理模型),描述了集体行动的社区治理类型树,主张在各种理想或元模型的基础上通过构建多元协作性社区治理机制来解决社区集体行动困境;最后,通过对社区内外因素、社区内部机制、“产品-行动”框、行动者在特定外部影响因素下的选择机制,以及产品性质和其他特征如何影响博弈理论分析框架的诸种变量的逐一分析,发展了不同治理模式选择的规范模型(同时可以看作是一个基本的政策或决策分析框架),并进行了简单的例证分析。

基于“知-意-行”结构的中国河流开发与保护公众调查

随着长江大保护、黄河高质量发展战略的实施以及长江保护法的颁布,需要了解公众对河流开发与保护的认知与态度。本文在对河流相关研究及已有公众调查分析的基础上,通过网络问卷进行了基于"知-意-行"结构的中国河流开发与保护的公众调查。主要结论包括:(1)从知的层面,大部分被调查者认为中国河流目前处于高强度大规模开发,或开发对生态有较大影响的状态;对河流生态价值重视程度高;偏好自然与近自然河流的比例高,但对其了解并不充分;地方河流存在恶化趋势,人河关系已明显改变;(2)从意的层面,大部分被调查者关注河流保护比较被动;对保护措施了解不够;行动参与意愿不高;(3)从行的层面,被调查者在河流保护行动的实际参与水平较低。针对部分结论的相关性分析显示:对我国河流开发基本现状的认知与对家乡河流开发的生态影响的认知显著相关;对河流生态价值重要程度的评价与对河流状态的偏好显著相关;参与河流保护活动与对河流保护事件的关注程度显著相关等。最后分析了官方媒体与非政府组织的作用,考虑了公众认知的时代性与多利益方的因素。

拉伸-扭转-弯曲作用下系泊缆索的应力响应

考虑6×19多股系泊缆索编制特点,研究缆索受到拉伸-扭转-弯曲共同作用下的应力响应。推导多股系泊缆索的螺旋线方程和不同层股丝接触点轴向距离,建立仿真模型中的代表性体积元素,推导该体积元素下的周期性边界条件,简化多股系泊缆索仿真模型,进一步优化应变和曲率加载方式,优化仿真模型加载形式。在有限元软件ANSYS中进行仿真分析,同时与解析模型进行对照。结果表明,所选取的代表性体积元素和周期性边界条件计算可靠,应力与曲率半径为非线性负相关关系,应变与应力为线性正相关关系,不同应变下曲率半径对应力的影响主要体现在最大应力数值以及位置,对应力-应变关系影响较小。

摩擦摆支座对高速列车-简支梁桥耦合系统的减隔震分析

为研究摩擦摆支座(FPB)对地震下高速列车-简支梁桥耦合系统的减隔震作用,基于ANSYS和SIMPACK平台,建立了高速列车-多跨简支梁桥耦合系统的三维有限元模型.模型中采用104~#力元模拟FPB,将轨道不平顺和地震力作为耦合系统的激励,开展了FPB对地震荷载下车-简支梁桥耦合系统的减隔震研究.结果表明,在El Centro地震波作用下,车-桥系统的动力响应随着车速、地震强度、墩高度的增大而增大.地震强度小于0.12g时,FPB能减小车-桥系统除墩顶横向加速度以外的其他动力响应,车速越大、墩身越高, FPB的减振效果越显著;地震强度大于0.12g时,FPB会增大车桥系统的动力响应.建议在高速铁路简支梁桥减隔震设计中,墩高不宜超过16 m,摩擦摆支座的参数应根据具体桥梁进行选择.