Cyber-Physical Systems and Mixed Simulations Tran Van Hoang - PowerPoint PPT Presentation

Cyber-Physical Systems and Mixed Simulations Tran Van Hoang Supervisor: Professor Bernard Pottier University of Western Brittany June 23, 2015 Tran Van Hoang (UBO) June 23, 2015 1 / 23

Contents Simulating and monitoring the environment 1 Problems of scheduling simulations of physical and sensing systems 2 Synthesizing cell system 3 Parallel simulations on the GPU 4 Mixed simulations with HLA 5 Conclusions 6 Tran Van Hoang (UBO) June 23, 2015 2 / 23

Simulating and monitoring the environment Climate changes increasingly becomes critical. → These changes have to be observed and predicted. ֒ Wireless Sensor Networks (WSNs) have recently emerged in monitoring the environment. → Such systems also need to be validated before implementations. ֒ Simulating and designing WSN for accurate observation of the environment. Tran Van Hoang (UBO) June 23, 2015 3 / 23

Problems of scheduling simulations of physical and sensing systems The lack of interoperability between WSN simulations and physical simulations. Modeling and simulating physical systems are difficult and time-consuming because these systems have: ◮ a large size. ◮ complicated behaviours. Tran Van Hoang (UBO) June 23, 2015 4 / 23

Solutions Figure 1: A region taken from OpenStreetMap. To employ the GPU capability. To mix and schedule simulations with HLA (High Level Architecture). Tran Van Hoang (UBO) June 23, 2015 5 / 23

Synthesizing cell system PickCell tool enables to generate cell networks as a set of processes and neighbourhood connections. The number of neighbours depend on defined Cellular Automata pattern. Figure 2: A cell network with Von Neumann connection. Tran Van Hoang (UBO) June 23, 2015 6 / 23

Synthesizing cell system (cont.) A method based on PickCell tool. Figure 3: A process of modeling physical systems. Tran Van Hoang (UBO) June 23, 2015 7 / 23

Parallel simulations on the GPU GPU contains hundreds of cores running in parallel. It is good for many similar computations. Figure 4: Comparison between CPU and GPU. Tran Van Hoang (UBO) June 23, 2015 8 / 23

Parallel simulations on the GPU (cont.) For the physical and network simulations, cells must compute state at time t+1 according to: ◮ local state. ◮ neighbours’ states. ◮ transition function. The computation is moved on the GPU. Tran Van Hoang (UBO) June 23, 2015 9 / 23

A simple example: Fire expansion Figure 5: Fire expansion simulation. Tran Van Hoang (UBO) June 23, 2015 10 / 23

A simple example: Fire expansion (cont.) A simulation of fire expansion. Using PickCell to extract a cell network from the map. 1 Cell state : [TREE, FIRE, ASH, or EMPTY] 2 Transition function: computed on the GPU. 3 Kernel execution if (nowState == TREE && firedNeighbour() == true ) nextState = FIRE; if (nowState == FIRE) nextState = ASH; if (nowState == ASH) nextState = EMPTY; return nextState; Tran Van Hoang (UBO) June 23, 2015 11 / 23

Comparison of two executions Hardware ◮ CPU: Intel(R) Xeon(R), 3.40GHz, 8CPU x 4cores. ◮ GPU: GeForce GTX 680, 1536 cores, 1024 threads. Physical model used: Pollution diffusion in the river. Figure 6: Pollution diffusion simulation. Tran Van Hoang (UBO) June 23, 2015 12 / 23

Comparison of two executions (cont.) Result: Figure 7: Comparison of time execution between CPU and GPU. Tran Van Hoang (UBO) June 23, 2015 13 / 23

Mixed simulations with HLA High Level Architecture (HLA) is an IEEE standard for distributed simulations. Cell system and WSN simulations can communicate together. Figure 8: HLA architecture. Tran Van Hoang (UBO) June 23, 2015 14 / 23

Mixed simulations with HLA (cont.) HLA defines three main components: Rules. ◮ A set of rules which must be followed to achieve proper interaction of simulations in a federation. Interface specification. ◮ To prescribes the interface functions between RTI and the simulations.. Object Model Template (OMT). ◮ To defines the way federations and federates have to be documented. Tran Van Hoang (UBO) June 23, 2015 15 / 23

Mixed simulations with HLA (cont.) A typical Federation Execution. 1 Initialize federation. ◮ Create Federation. ◮ Join Federation. 2 Declare objects. ◮ Publish Object Class Attributes. ◮ Subscribe Object Class Attributes. 3 Loop execution and exchange information. ◮ Update/Reflect Attributes Values. ◮ Time Advance Request, Time Advance Grant. 4 Terminate execution. ◮ Resign Federation. ◮ Destroy Federation. Tran Van Hoang (UBO) June 23, 2015 16 / 23

Example cases Figure 9: A proposed federation. Tran Van Hoang (UBO) June 23, 2015 17 / 23

Example cases (cont.) Federate Time constrained Time regulating Time advance Forest Yes Yes Time stepped WSN Yes Yes Time stepped Visualization Yes Yes/No Time stepped Table 1: Time management of the federation. Object Class Attributes Published by Subscribed by ForestNode State, Position ForestNode WSN, Visualization WSNNode State, Position WSNNode Visualization Table 2: Objects and their attributes, publishers and subscribers. Tran Van Hoang (UBO) June 23, 2015 18 / 23

Example cases (cont.) How the federates exchange information together? Figure 10: A communication between Forest federate and WSN federate. Tran Van Hoang (UBO) June 23, 2015 19 / 23

Example cases (cont.) Figure 11: Three simulations: Forest fire, WSN, and Visualization. Tran Van Hoang (UBO) June 23, 2015 20 / 23

Conclusions and future works. Conclusions ◮ Synthesizing cell systems based on PickCell tool to develop parallel simulations. ◮ Parallel simulations concurrently run together. This can lead to accurate observation of the environment. Future works ◮ The proposed method will be applied in a real simulation project (Mad Environment company). ◮ The multiple dimension data will also be considered in future work. Tran Van Hoang (UBO) June 23, 2015 21 / 23

Main references Teodora Sanislav, Liviu Miclea. Cyber-Physical Systems - Concept, Challenges and Research Areas. CEAI Vol.14, No.2, pp. 28-33, 2012. Bernard Pottier, Pierre-Yves Lucas. Dynamic networks NetGen: objectives, installation, use, and programming. Universit´ e de Bretagne Occidentale. August 26, 2014. F. Kuhl, R. Weatherly, J. Dahmann. Creating Computer Simulation Systems: An Introduction to the High Level Architecture. Prentice Hall, 1999. The study region, Mekong Delta Region, South of Vietnam. https://www.openstreetmap.org NVIDIA, Graphics Processing Unit (GPU). http://www.nvidia.com/object/gpu.html. Common-pool Resources and Multi-Agent Simulations (CORMAS) CIRAD research center. http://cormas.cirad.fr/ GeForce GTX 680. http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-680/specifications. Tran Van Hoang (UBO) June 23, 2015 22 / 23

Thank you for your attention! Tran Van Hoang (UBO) June 23, 2015 23 / 23