semsim paper presentation

7/24/2019 Semsim Paper Presentation

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SEMSim Cloud Service: Large-scaleurban systems simulation in the cloud

By Muhammad Ibrahim


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SEMSim Cloud Service: Large-scale

urban systems simulation in thecloud

Proposed architecture for a cloud-basedurban systems simulation platform

Aim is to large-scale simulations availableto typical users

addresses the issue of data condentiality

Scalable Electro-Mobility SimulationSEMSim! Cloud Service that implements

the proposed architecture


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urban systems simulation in the cloud

large-scale simulations being migrated to thecloud" users #ill have to face ne# challenges

$sability % &raphical user interfaces of manysimulation soft#are tools have beendesigned for use on #or'stations by a singleuser(

user interfaces that are specically designedfor cloud-based simulation services


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urban systems simulation in the cloud

enables many di)erent $*s for di)erentaspects of the same simulation e(g("

conguration" visuali+ation" data analysis!(

,ata Condentiality-data may be sensitiveand data providers may not permit the useofcloud-services due to concerns regardingcondentiality(


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eb-based simulations: Providing collaborationplatforms or independent front-end interfaces(

interfaces in the form of #eb-applications or thin-clientsfor controlling simulations(

Modeling . Simulation as a Service MSaaS!

model for provisioning modeling and simulation serviceson demand from a Cloud Service Provider CSP!


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/esearch pro0ect CloudSME1 is concerned#ith the use of cloud-based simulations for

the manufacturing and engineeringindustry(


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2vearvie# of proposed architecture

for a cloud-based simulation service(


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3ront-end Components ,esign of e4periment applications are used by the user

to specify the e4periment that is to be performed(

Create E4periment ,escription 3ile E,3! #hich contains all thenecessary information and data if applicable! inorder for the bac'-end to perform the simulation e4periment(

5isuali+ation applications are used to perform real-timevisuali+ations of a currently running simulation

instance(

Analysis applications are used to analy+e thesimulation results


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6ac'-end Components

A ,ispatch server ,S! application e4ecute asimulation e4periment according to the

specication in theE,3(

Steps

7! provisions a number of 5Ms in the cloud that#ill

host the simulation instances" 8! initiali+es the 5Ms i(e(" copies les" setup therun-time environment" etc(!"

1! starts e4ecution of the simulation instance inthe 5Ms" and 9! noties the user #hen the

e4periment has been completed(


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6ac'-end Components

5isuali+ation server application enables aspecic simulation instance connect to it and

the real-time data stream is then for#arded tothe visuali+ation application in the front-end(

/elays control commands from the visuali+ationapplication to the simulation instance(

A Simulation instance e4ecutes a singlesimulation according to the specicationprovided in the E,3(


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2vervie# of general #or'o# for the

manual use-case(


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SEMSim platform SEMSim platform is used in the conte4t of

electromobility research and aims at helping to ans#ervarious ;uestions regarding the impact of large-scale

electro-mobility on a city


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SEMSim platform primarily t#o 'inds of simulations

Agent-based tra=c simulation SEMSim >ra=c!

,iscrete-event po#er system simulationSEMSim Po#er

>hese t#o simulations are coupled using the?igh Level Architecture ?LA! ( >his allo#s us toinvestigate the impact of thousands of electricvehicles on the po#er grid depending on their

charging behavior(


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SEMSim platform SEMSim Platform is designed to ans#er

electromobility ;uestions for mega-cities usingmultiple tools li'e SEMSim >ra=c and SEMSimPo#er" the computational needs are large

2ne ma0or di)erence bet#een SEMSim >ra=c andthe e4isting tra=c simulations is the level of detail

at #hich the internal state of vehicles is simulated(

SEMSim >ra=c" every agent represents a driver-vehicle unit #hich consist not only of driverbehavior models but also vehicle component models

e(g(" air conditioning" drive train" battery!(


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SEMSim platform SimSEM also simulate the internal state of

vehicles" #e refer to it as nanoscopic

simulation in order to emphasi+e thedi)erence to e4isting microscopicsimulations(


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SEMSim platform $nli'e e4isting simulations tools e(g(" MatSim" S$M2!

#hich use a time-stepped simulation engine" #e use adiscrete event simulation engine(

*n ,ES! engine" the state of the simulation is onlyadvanced #hen an event is e4ecuted as compared toevery time step in a time-stepped simulation!(

Events in a ,ES can be scheduled at arbitrary times@this gives us the needed e4ibility as some modelsneed more fre;uent updating e(g(" moving of agentson the road net#or'! #hile others are updated onlyinfre;uently e(g(" internal vehicle models or behavior!(


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SEMSim platform SEMSim platform and in particular" SEMSim

>ra=c( ,ue to the high computational

re;uirements of simulating a large number7BB'! of agents and their interaction in ananoscopic simulation" the e4ecutionenvironment for the SEMSim platform is a

high performance computing cluster thatsupports highly parallel e4ecution(


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SEMSim platform


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3ront-end applications SEMSim CS provides a series of front-end

applications

,esign of e4periments is concerned #itht#o parts

Prole ,esigner P,!: parameteri+ation ofthe models used #ithin a nano-scopic tra=c

simulation(


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3ront-end applications >his model parameter can either be a

4ed value or a distribution from #hich a

value is dra#n #hen the specic modelinstance is created(

>hese proles are stored in a repository

and #ill be used #hen creating the actuale4periment(

>his is done by using the E, application

E, application is divided into t#o sections


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Front-end applications upper section of the application #indo#

general e4perimentation parameters are

congured e(g(" road net#or'" number ofagents" simulation time span!@

6ottom part agent population is congured(

>his conguration uses the proles createdin the P, to specify the di)erentcombinations of driver-vehicle-unit proles#ith ratios on the total population in order tocreate a heterogeneous agent population(


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Front-end applications


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3ront-end applications 5isuali+ation applications: SEMSim CS

provides a set of visuali+ation

applications( broad overvie# of the simulationshe overhead due to cache misses in the

hard#are architecture and the

programming model leads to the biggestperformance decrease

Simulating thousands of agents in a

nanoscopic manner leads to cache misses"since it cannot be predicted in #hichprocessor the same agent data is neededduring the ne4t calculation


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Simulation runtimecomparison An access to a memory address from a CP$

core on the same CP$ results in using the

cached value in the CP$ L7 to L1 cache" dueto the locality principles(

*f a memory address re;uired by a core is

on a di)erent CP$ the data #ill not be inthe cache and therefore has to be retrievedfrom main memory using the system bus(

>his operation costs many computing cycles


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References ,aniel Iehe a" Alois Dnoll" entong Cai"

?ei'o Aydt" JSEMSim Cloud Service: Large-

scale urban systems simulation in the cloudK" 8B7" Simulation Modelling Practice and Theory


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