基于元胞自动机和模糊理论的人群疏散仿真

基于元胞自动机和模糊理论建立了人群疏散模型,对教学楼内的人群疏散过程进行了模拟。该模型根据人员对建筑物的熟悉程度、周围人员的吸引力设计元胞行为准则,并且采用模糊隶属度定义人员的体能状态及人员对环境的熟悉程度。实验结果表明,该仿真模型能够较好地模拟紧急状况下的人群疏散过程。     

高铁车厢内部紧急情况下人员疏散仿真研究

在引入元胞自动机理论的基础上,模拟分析了紧急情况下人员生理及心理的不同对疏散过程的影响,通过人员动态调整自身行为,并引入人员竞争力,对人员疏散过程建立模型。在疏散过程中,根据存在着一定程度的外部干扰因素,提出疏散干扰度概念。计算机仿真的结果表明,考虑人员竞争力,以及出口疏散干扰的问题,可以更加真实地模拟人员紧急疏散过程和疏散状况。     

Cellular automaton model of crowd evacuation inspired by slime mould

In all the living organisms, the self-preservation behaviour is almost universal. Even the most simple of living organisms, like slime mould, is typically under intense selective pressure to evolve a response to ensure their evolution and safety in the best possible way. On the other hand, evacuation of a place can be easily characterized as one of the most stressful situations for the individuals taking part on it. Taking inspiration from the slime mould behaviour, we are introducing a computational bio-inspired model crowd evacuation model. Cellular Automata (CA) were selected as a fully parallel advanced computation tool able to mimic the Physarum’s behaviour. In particular, the proposed CA model takes into account while mimicking the Physarum foraging process, the food diffusion, the organism’s growth, the creation of tubes for each organism, the selection of optimum tube for each human in correspondence to the crowd evacuation under study and finally, the movement of all humans at each time step towards near exit. To test the model’s efficiency and robustness, several simulation scenarios were proposed both in virtual and real-life indoor environments (namely, the first floor of office building B of the Department of Electrical and Computer Engineering of Democritus University of Thrace). The proposed model is further evaluated in a purely quantitative way by comparing the simulation results with the corresponding ones from the bibliography taken by real data. The examined fundamental diagrams of velocity–density and flow–density are found in full agreement with many of the already published corresponding results proving the adequacy, the fitness and the resulting dynamics of the model. Finally, several real Physarum experiments were conducted in an archetype of the aforementioned real-life environment proving at last that the proposed model succeeded in reproducing sufficiently the Physarum’s recorded behaviour derived from observation of the aforementioned biological laboratory experiments.     

Effects of cell size and configuration in cellular automata based prey–predator modelling

Cellular automata (CA) have shown to be a viable approach in ecological modelling, in particular when dealing with local interactions between species and their environment. In CA modelling complex patterns emerge on a global scale through the evolution of interactions at a local level. Although the validity of a cell-based approach has successfully been demonstrated in numerous cases, very few studies have been reported that address the effects of cell size and configuration on the behaviours of CA-based models. In this paper, the performance of a cellular automaton based prey–predator model (EcoCA) developed by the author was first calibrated against the classical Lotka–Volterra (LV) model. The model was then used to investigate effects of cell size and cellular configurations (viz. the ‘computational stencil’). By setting up systematic simulation scenarios it was observed that the choice of a particular cell size has a clear effect on the resulting spatial patterns, while different cellular configurations affect both spatial patterns and system stability. On the basis of these findings, it is proposed to use the principal spatial scale of the studied ecosystem as CA model cell size and to apply the Moore type cell configuration. Methods for identifying principal spatial scales have been developed and are presented here.     

On time reduction and simulation in cellular spaces

We prove a generalized and corrected version of the time reduction theorem for cellular spaces. One basic tool for investigations in this field is the concept of simulation between systems of automata. We propose a general formal definition of the intuitive concept and relate it to the notions which appear in the literature     

元胞自动机方法在MEMS工艺模拟中的应用

随着计算机技术的发展和MEMS(micro-electro-mechanical system)自身发展的需要,应用元胞自动机方法模拟MEMS加工工艺的研究发展迅速.首先,简要介绍了元胞自动机原理,然后,综述了元胞自动机方法在MEMS工艺模拟中的应用现状,分析了应用元胞自动机方法模拟MEMS加工工艺的前景和方向.     

Estimating the effects of mental disorientation and physical fatigue in a semi-panic evacuation

Understanding the impossibility of replicating a real panic emergency situation and experimenting human objects in such artificially created dangerous situation, this paper focuses on the evacuation of a heterogeneous population including people with disabilities in a semi-panic simulated situation in which people tend to hurry more than those in non-panic evacuation but exhibit less urgency than those in a panic emergency. Ultimately, we intend to estimate and quantify the effects of mental disorientation and physical fatigue on the average evacuation times of six different disability groups and the entire group in a simulated environment of a 24-story building. According to our experiments, mental disorientation due to sudden emotion escalation from the recognition of unexpected dangers increases the average evacuation times up to 25 percent depending on the complexity of evacuation routes of the simulated buildings. In addition, accumulated physical fatigue of human beings during the evacuation process could also significantly delay the evacuation time. Most of all, the impact magnitudes of these two main factors vary depending on the types of disabilities of individuals, insinuating the needs of developing evacuation plans and strategies for each group.     

骨移植体的降解和新骨生长的可视化仿真

采用元胞自动机方法建立生物陶瓷降解和新骨生长的仿真模型,运用可视化技术对仿真结果进行图形化和动画显示．实验表明,只要模型的控制参数输入比较正确,仿真模型可以在不同阶段对降解的材料和新生的骨组织作定量分析．     

Experiment and analysis on microscopic characteristics of pedestrian movement in building bottleneck

In this paper, evacuation experiments are carried out to study pedestrian movement behaviors in building bottleneck. An image processing method based on mean-shift algorithm is used to extract pedestrian movement trajectory. Based on the extracted trajectory, we analyze the microscopic movement characteristics of pedestrians such as lane formation, change of velocity and distance between two sequential pedestrians. A pedestrian lane is a group of pedestrians moving in a column. The lane formation is verifie...     

Software toolkit for modeling,simulation, and control of soft robots

The technological differences between traditional robotics and soft robotics have an impact on all of the modeling tools generally in use, including direct kinematics and inverse models, Jacobians, and dynamics. Due to the lack of precise modeling and control methods for soft robots, the promising concepts of using such design for complex applications (medicine, assistance, domestic robotics, etc.) cannot be practically implemented. This paper presents a first unified software framework dedicated to modeling, simulation, and control of soft robots. The framework relies on continuum mechanics for modeling the robotic parts and boundary conditions like actuators and contacts using a unified representation based on Lagrange multipliers. It enables the digital robot to be simulated in its environment using a direct model. The model can also be inverted online using an optimization-based method which allows to control the physical robots in the task space. To demonstrate the effectiveness of the approach, we present various soft robots scenarios including ones where the robot is interacting with its environment. The software has been built on top of SOFA, an open-source framework for deformable online simulation and is available at https://project.inria.fr/softrobot/.     

Numerical simulation of flutter validated by flight-test data for TU-204 aircraft

The interactive multidisciplinary aircraft design code was used for numerical simulation of Tupolev-204 airplane in-flight flutter tests. Dynamic structure loading is generated by symmetric and antisymmetric harmonic excitation of spoilers with smooth frequency sweep from 1 to 5 Hz. Major features of theoretical approach are described. Calculated and experimental results are compared. The influence of unsteady aerodynamic forces and onboard control system on dynamic loading of elastic structure is shown.     

门式起重机司机计算机仿真培训系统的设计

为了缩短培训时间、减低培训费用和提高教学质量,我们拟开发一个进行门式起重机司机培训的计算机实时仿真系统。本文简要介绍该系统的功能、总体结构、系统运行环境和支撑软件等。     

高性能路由器操作系统HEROS的设计与实现

实时分布式操作系统是高性能分布式路由器的控制核心 ,为了保证路由器系统的整体性能和安全性 ,本文设计并实现了实时分布式操作系统 HEROS(Highly Efficient Router Operating System) .HEROS基于微内核体系结构 ,其多任务内核实现了基于优先级的抢先式调度 ,高效率的任务间同步和通信原语 ,实时的中断处理和高效的内存管理机制 .为了更好地服务于分布式路由器体系结构 ,HEROS基于 Compact PCI总线实现了一种分布式通信机制和面向网络协议的高性能的缓冲管理机制 .目前 ,基于 HEROS的高性能安全路由器原型系统已经设计完成     

BASE: an assistant tool to precisely simulate energy consumption and reliability of energy‐efficient storage systems

The concept of green storage in cluster computing has recently attracted enormous interest among researchers. Consequently, several energy‐efficient solutions, such as multi‐speed disks and disk spin down methods, have been proposed to conserve power in storage systems and improve disk access. Some researchers have assessed their proposed solutions via simulations, while others have used real‐world experiments. Both methods have advantages and disadvantages. Simulations can more swiftly assess the benefits of energy‐efficient solutions, but various measurement errors can arise from procedural shortcomings. For instance, many power simulation tools fail to consider how heat increases the power overhead of disk operations. Some researchers claim that their modeling methods reduce the measurement error to 5% in the single disk model. However, the demand for large‐scale storage systems is growing rapidly. Traditional power measurement using a single disk model is unsuited to such systems because of their complex storage architecture and the unpredictability of numerous disks. Consequently, a number of studies have conducted real machine experiments to assess the performance of their solutions in terms of power conservation, but such experiments are time consuming. To address this problem, this study proposes an efficient simulation tool called Benchmark Analysis Software for Energy‐efficient Solution (BASE), which can accurately estimate disks' power consumption in large‐scale storage systems. We evaluate the performance of BASE on real‐world traces of Academia Sinica (Taiwan) and Florida International University. BASE incorporates an analytical method for assessing the reliability of energy‐efficient solutions. The analytical results demonstrate that the measurement error of BASE is 2.5% lower than that achieved in real‐world experiments involving energy‐estimation experiments. Moreover, the results of simulations to assess solution reliability are identical to those obtained through real‐world experiments. Copyright © 2015 Copyright © 2015 John Wiley & Sons, Ltd.     

A Timed Verification of the IEEE 1394 Leader Election Protocol

The IEEE 1394 architecture standard defines a high performance serial multimedia bus that allows several components in a network to communicate with each other at high speed. In the physical layer of the architecture, a leader election protocol is used to find a spanning tree with a unique root in the network topology. If there is a cycle in the network, the protocol treats this as an error situation. This paper presents a formal model of the leader election protocol in the language IOA and a correctness proof. Hereby, it is shown that under certain timing restrictions the protocol behaves correctly. The timing parameters in the IEEE 1394 standard documentation obey the restrictions found in this proof.     

Efficient and Precise Cache Behavior Prediction for Real-Time Systems

Abstract interpretation is a technique for the static detection of dynamic properties of programs. It is semantics based, that is, it computes approximative properties of the semantics of programs. On this basis, it supports correctness proofs of analyses. It replaces commonly used ad hoc techniques by systematic, provable ones, and it allows for the automatic generation of analyzers from specifications by existing tools. In this work, abstract interpretation is applied to the problem of predicting the cache behavior of programs. Abstract semantics of machine programs are defined which determine the contents of caches. For interprocedural analysis, existing methods are examined and a new approach that is especially tailored for the cache analysis is presented. This allows for a static classification of the cache behavior of memory references of programs. The calculated information can be used to improve worst case execution time estimations. It is possible to analyze instruction, data, and combined instruction/data caches for common (re)placement and write strategies. Experimental results are presented that demonstrate the applicability of the analyses.     

无线蜂窝网络呼叫接入控制仿真平台的设计与实现

介绍了蜂窝网络无线通信中的呼叫接入控制(CAC)的特点,描述了基于面向对象的事件驱动技术的仿真平台的设计思想和仿真系统的优化,对仿真平台的物理模型进行了分析,并给出平台的运行过程。最后给出了无预留信道和固定预留信道的接入控制算法的进行了仿真,并对仿真的结果进行了分析,试验结果符合理论分析。     

人员紧急疏散系统动力学模型及其分析

在大型的体育赛事中,观众是一个非常复杂的能量系统,群体内人与人之间存在着相互影响、相互渗透的交互作用。针对能量的汇聚、冲突、平衡与失衡以及群体行为的趋向和拒斥等现象的研究,对系统问题进行分析,明确系统的界限,确定系统的各种变量,建立系统的因果关系图和流图,构建出系统模型。利用定性描述的方法,分析系统整体与局部的反馈关系,写出SD方程,并根据数据进行仿真试验和计算,最终得到一个与实际较为相符的预测结果。