基于MapInfo电子地图的Paramics仿真基础路网构建

研究了利用Mapinfo电子地图自动提取构建微观交通仿真软件Paramics基础路网的方法。首先利用MapInfo提供的二次开发工具MapX提取出代表路网几何和拓扑的特征点信息,然后对原始的特征点集进行精简近距离点、精简同一直线上点以及精简同一弧上点的操作,最后生成Paramics的路网存储文件和基础路网。根据此方法提高了Paramics基础路网建模的效率,生成的路网与原地图一致,满足微观交通仿真要求。

空中交通管理实验类课程改革探析——以仿真技术基础课程为例

中国民航大学交通运输专业的培养目标是培养高素质应用型工程技术人才,仿真技术基础课程是达成本专业人才培养目标的有效支撑。该研究首先阐述了该课程的基本情况,然后针对存在的问题,从教学方式、教学资源和考核方式这3个方面提出改革内容:采用PBL教学方式,发挥主观能动性;建设实验教学资源,明确实验设计原则与实验设计过程;课程组集体考核,完善成绩评判方式。最后通过毕业能力指标达成度的分析验证了改革方案是有效的。

联合作战仿真信息交互基础结构(SII)研究

该文提出了联合作战仿真交互基础结构 (SimulationInteractionInfrastructure,SII)的概念 ,具体设计、研究、分析了一个SII系统 ,并认为SII的研究与设计是我军下一代联合作战仿真系统设计的关键研究课题 ;SII兼容RTI,但不同于RTI,SII是一个比RTI更为完善的仿真信息交互支撑系统 ;RTI解决数据层次的互连、互通、互操作 ,但SII除兼具RTI的数据操作特性外 ,同时具有模型、知识、图形、图象层次的互连、互通、互操作能力 ;SII良好的分层、并发管理机制 ,使之能最大限度地避免和克服目前RTI时间同步等难题 ,从而 ,也使得SII必然会成为未来联合作战仿真信息交互支撑结构研究的主导发展方向。

面向应用型人才培养的《仿真技术基础S》课程改革探讨

为有效支撑本专业应用型人才培养目标的达成,针对《仿真技术基础S》课程中存在的不足,从教学方式、教学资源和考核方式三个方面提出了改革内容:借鉴CDIO培养模式,改变重结果、轻过程的不足,增加实验设计环节,使学生做到实验设计和实现的综合锻炼;依靠课程组成员丰富的科研经验,从空管、航空公司、机场运行等实际问题中凝练出适合于本课程教学的实验,充分发挥科研反哺教学的作用,不断充实教学资源;采用学生分组答辩、课题组老师集体打分的方式,尽可能做到客观、公平的评判。最后本文提出了参加企业实践、利用新媒体和小班授课等措施来保障课程改革的成效。

舰船虚拟维修仿真应用系统的设计与实现

虚拟维修技术对于舰船、航行器等复杂装备的维修性设计与分析具有重要意义。详细分析舰船维修性设计对于虚拟维修仿真的应用需求,在此基础上提出一种面向舰船维修仿真应用系统的架构,设计该系统的组成及各模块功能。该应用系统架构包括数据层、功能层、接口层及用户界面层4个层次:在数据层,可实现数据的数据库存储和本地存储;在功能层,设计了多个仿真数据管理功能、运动捕获数据处理功能以及可视性、可达性和舒适性等多个高级分析功能;在接口层,提供了与Teamcenter(TC)平台的数据集成功能,可实现从TC下载舰船JT模型至仿真系统中,以及将仿真结果和场景文件等上传至TC;在用户界面层,设计了人性化的系统操作界面,可实现客户与系统之间的友好交互和操作。最后,结合Jack仿真软件,实现舰船虚拟维修仿真应用系统的原型,该原型系统为开展舰船虚拟维修仿真数据的管理与应用以及运动捕获技术在虚拟维修中的应用奠定了基础。

我国仿真学科研究的发展历程与展望

将仿真学科作为对象进行研究,是推进仿真发展的重要工作。我国仿真经过40多年的发展,正在逐渐形成了一门独立的学科。当前在面临复杂系统仿真挑战的同时,仿真学科也进入了一个新的发展阶段,必须完善自身建设。回顾20世纪80年代以来我国仿真学科研究的发展,经历了3个阶段,仿真界对仿真作用的认识在逐步加深,对仿真技术发展有多种角度的解读,对仿真学科基础进行了长期的探索,并多方面探讨了仿真的基础理论构成。对这些发展进行了系统性的梳理,并展望了建立仿真学科及其知识体系需要进一步开展的主要工作。

岸电接地电阻仿真研究

本文根据建筑物接地时常用基础接地极方式减小接地电阻的经验,提出岸电接地装置接地极可以采用基础接地极方式。对基础接地极电阻进行ANSYS仿真计算,通过与垂直接地极电阻理论计算结果相对比,确定基础接地方式的可用性,并得到了码头接地装置和船壳之间不需要连接导体的结论。该研究将对码头接地装置接地极设计提供理论依据,为岸电系统运行安全性提供了保证。

基础医学实验教学改革的探索与实践

通过构建的集约化基础医学仿真平台,可以整合医学教学资源,可以加强课程整合,形成基于器官、系统、疾病的系统化和开放式实验教学体系,促进学生早期接触科研,适应现代医学教育模式改革。

Multisim在数字电路课程设计中的应用

介绍了基于Multisim的数字电路课程设计的实现。以四路抢答电路为例,在分析了系统功能之后,设计的电路结构包括锁存电路、计时电路、译码显示电路、控制电路等几部分。控制电路结构在系统中的作用尤其显著,详细介绍了四路抢答电路各控制信号的设计过程,体现了数字电路基本设计方法的重要作用。仿真结果表明,Multisim技术在数字电路综合设计运用的明显优势,培养了学生的创新能力。

Dynamic Simulation on Collision Between Ship and Offshore Wind Turbine

By using ABAQUS/Explicit, the dynamic process of an offshore wind turbine(OWT) stricken by a ship of 5000DWT in the front direction is simulated. The OWT is located on a large-scale prestressing bucket foundation constructed by an integrated installation technique. According to the simulation results, under the ship collision, a certain range of plastic zone appears within a local area of arc transition structure of the bucket foundation, and the concrete plastic zone is seriously damaged. As the stress level of OWT tower is relatively low, the OWT tower is less affected. A great inertial force is generated at the top of the OWT tower as the mass of nacelle and blades is up to 400 t. The displacement of the tower is in the opposite direction of the ship collision at the end of 1 s under the action of inertial force. There is only a minor damage in the ship bow. Most of the kinetic energy is transformed into the plastic dissipation and absorbed by the arc transition structure of bucket foundation.

A real-time data smoothness method based on xPC-Target

A method of real-time data smoothness which is applied in a hardware-in-the-loop （HIL） simulation platform for a plug-in hybrid electric vehicle synthetical power device is described. The input signal of the platform comes from a AC/DC switch power with output containing noises. A linear slide average arithmetic is applied to smooth the noises. To average a certain number input sample signals, this method can decrease the noises voltage level, which meet the requirement of the simulation platform. The efficiency and signal delay time are presented to describe the result of this method, and a statistical index is used to judge the arithmetic＇ s efficiency. The tests results show that the arithmetic fit the requirement of the HIL simulation platform.

Nuclear magnetic resonance(NMR) microscopic simulation based on random-walk: Theory and parameters analysis

The microscopic response characteristics of nuclear magnetic resonance(NMR) are widely used for characterizing complex pore structures of rocks. Due to the prohibitive NMR experiment cost, numerical simulation was employed as an alternative approach to verify some theoretical aspects of NMR responses. Firstly, the basic principles of pore-scale NMR simulation based on random-walk method(RWM) were introduced. The RWM-simulated results were benchmarked with the analytical results for an ideal spherical pore model. Then, the effects of two numerical parameters, namely diffusion radius and walk numbers, were studied on the simulation accuracy. The simulation method is then applied to various pore models with different pore sizes and pore shapes filled with different fluids to study the microscopic NMR response characteristics. The numerical experiments are useful for understanding and interpreting NMR measurements and the simulation code provides a numerical tool to perform pixel-based digital rock analysis.

Hop distance fairness for wireless mesh network based on queue management

Wireless mesh network （WMN） is a new multi-hop network for broadband accessing to intemet. However, there exists a server unfairness problem based on different hop distances in WMN. To solve this problem, the unfairness issue was analyzed in test-bed experiment and NS2 simulation. A dynamic queue management scheme E-QMMN was proposed, which allocates the queue buffer according to the hop distance of every flow. The experimental results show that the proposed scheme can not only increase the hop distance fairness of the legacy scheme at most 50%, but also reduce the average round trip time at least 29% in congested WMN environments.

Virtual Reality and Visual Simulation Technology in Platform Construction with Four Bucket Foundations Based on Secondary Development of Vega

The platform with bucket foundations can penetrate and migrate by underpressure/positive pressure technique caused by pumping water out/in the bucket. However, the construction process of bucket foundations cannot be clearly observed and effectively controlled due to the special nature of sea environment. By using an advanced simulation development tool of Multigen Creator, the visual construction simulation program for the platform with bucket foundations was developed to set up the virtual reality system with interaction control and observation in every view angle based on the secondary development technology of Vega platform. The application results show that the method is feasible and effective by simulating the whole construction process for the platform with four bucket foundations.

Experimental and Simulation-based Investigation of a Velocity Controller Extension on a Ball Screw System

The background of this contribution is the enhancement of the achievable accuracy of servo-screw-presses. Therefore, the paper is concerned with the improvement of the dynamic precision for direct driven servo axes which is still restricted by structural vibrations. For this purpose, a ball screw test rig was analyzed for which the standard cascade control structure was extended by an additional velocity feedback. This structural extension has the potential to improve the controller performance significantly due to a better damping of low frequent vibrations. Furthermore, a parametric dynamic model for the control structure was derived to investigate the effects of the controller extension. For this analysis, the influences of the used tuning factors and filters is discussed in the frequency domain based on bode plots. The results of these cognitions are transferred to the time domain and illustrated by step responses. In addition, an evaluation by the criterion of the IAE （integral of absolute error） and the Prony analysis is carried out. Finally, the results are experimentally verified at the ball screw test rig. The paper closes with the conclusions.

An early recognition algorithm for BitTorrent traffic based on improved K-means

In response to the deficiencies of BitTorrent, the concept of density radius was proposed, and the distance from the maximum point of radius density to cluster center as a cluster radius was taken to solve the too large cluster radius resulted from the discrete points and to reduce the false positive rate of early recognition algorithms. Simulation results show that in the actual network environment, the improved algorithm, compared with K-means, will reduce the false positive rate of early identification algorithm from 6.3% to 0.9% and has a higher operational efficiency.

The Simulation and Optimization Design of Adams-based Engine Suspension System

In this study, the engine suspension system was optimized for making the vibration between engine and car body minimized, and also the optimization was simulated using software Adams. The purpose of this study was to research the vibration isolation of the engine mounting system and implement multi-objective optimization for the intrinsic frequency. In this paper, the optimization was implemented in two ways： （1） the intrinsic frequency was optimized by reasonably allocating it： （2） the intrinsic frequency was optimized using energy decoupling. The optimized intrinsic frequencies were simulated using software Adams and then the simulation results were compared. The simulation results showed that the optimized energy distribution was almost up to 90% and the decoupling degree was greatly improved by comparing the initial data, proving the optimized data played a geater effect on engine vibration isolation and further verifying the feasibility of optimization design method.

探究一体化教学方法的实施

《电子技术基础与技能》是电子类中职教育中比较重要的一门学科,此课程教学采用一体化的教学模式,主要目的就是为了培养学生的技能水平和职业素养,提升教学质量,使教学能够贴近真正的市场需求和岗位需求的要求。要保证一体化教学模式在实际的教学过程中发挥出一定的作用,就必须提高教师的教学能力,整个教学在集实训设备、多媒体教学系统、电子黑板、protues软件仿真于一体的一体化教室进行,保证相关的实训设备满足实际教学需求,教师合理运用一体化教学方法完成电子技术应用的教学。

Generation of spatial atmospheric turbulence field in aircraft motion simulation based on refined similarity hypothesis

It is necessary to build turbulence model to study the response of aircraft to atmospheric turbulence for high resolution earth observation. The conventional method is on the basis of Dryden’s model with the assumption that individual patches are Gaussian. In this paper,based on Kraichnan’s refined similarity idea,a new 1D atmospheric turbulence model is set up by introducing the energy transfer rate as an intermittency disturbance to a Gaussian process. Our results show that the turbulent fields generated by our new method exhibit an anomalous scaling described by the She-Leveque (SL) formula,which is now well accepted for homogenous and isotropic turbulence.

Self-adaptive CH_4 concentration detection system based on infrared spectrum absorption principle

Considering that the noises resulting from low modulation frequency are serious and cannot be totally eliminated by the classic filters,a novel infrared(IR) gas concentration detection system based on the least square fast transverse filtering(LS-FTF) self-adaptive modern filter structure is proposed.The principle,procedure and simulation on the LS-FTF algorithm are described.The system schematic diagram and key techniques are discussed.The procedures for the ARM7 processor,including LS-FTF and main program,are demonstrated.Comparisons between the experimental results of the detection system using the LS-FTF algorithm and those of the system without using this algorithm are performed.By using the LS-FTF algorithm,the maximum detection error is decreased from 14.3 to 5.4,and also the detection stability increases as the variation range of the relative error becomes much smaller.The proposed LS-FTF self-adaptive denoising method can be of practical value for mid-IR gas detection,especially for weak signal detection.