?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Facebook%E2%80%99s+Cyber%E2%80%93Cyber+and+Cyber%E2%80%93Physical+Digital+Twins&rft.creator=Ahlgren%2C+J&rft.creator=Bojarczuk%2C+K&rft.creator=Drossopoulou%2C+S&rft.creator=Dvortsova%2C+I&rft.creator=George%2C+J&rft.creator=Gucevska%2C+N&rft.creator=Harman%2C+M&rft.creator=Lomeli%2C+M&rft.creator=Lucas%2C+SMM&rft.creator=Meijer%2C+E&rft.creator=Omohundro%2C+S&rft.creator=Rojas%2C+R&rft.creator=Sapora%2C+S&rft.creator=Zhou%2C+N&rft.description=A+cyber-cyber+digital+twin+is+a+simulation+of+a+software+system.+By+contrast%2C+a+cyber-physical+digital+twin+is+a+simulation+of+a+non-software+(physical)+system.+Although+cyber-physical+digital+twins+have+received+a+lot+of+recent+attention%2C+their+cyber-cyber+counterparts+have+been+comparatively+overlooked.+In+this+paper+we+show+how+the+unique+properties+of+cyber-cyber+digital+twins+open+up+exciting+opportunities+for+research+and+development.+Like+all+digital+twins%2C+the+cyber-cyber+digital+twin+is+both+informed+by+and+informs+the+behaviour+of+the+twin+it+simulates.+It+is+therefore+a+software+system+that+simulates+another+software+system%2C+making+it+conceptually+truly+a+twin%2C+blurring+the+distinction+between+the+simulated+and+the+simulator.+Cyber-cyber+digital+twins+can+be+twins+of+other+cyber-cyber+digital+twins%2C+leading+to+a+hierarchy+of+twins.+As+we+shall+see%2C+these+apparently+philosophical+observations+have+practical+ramifications+for+the+design%2C+implementation+and+deployment+of+digital+twins+at+Facebook.&rft.publisher=Association+for+Computing+Machinery+(ACM)&rft.date=2021-06&rft.type=Proceedings+paper&rft.language=eng&rft.source=+++++In%3A++Proceedings+of+the+EASE+2021%3A+Evaluation+and+Assessment+in+Software+Engineering.++(pp.+pp.+1-9).++Association+for+Computing+Machinery+(ACM)+(2021)+++++&rft.format=text&rft.identifier=https%3A%2F%2Fdiscovery.ucl.ac.uk%2Fid%2Feprint%2F10139789%2F1%2FEASE21.pdf&rft.identifier=https%3A%2F%2Fdiscovery.ucl.ac.uk%2Fid%2Feprint%2F10139789%2F&rft.rights=open