简介:Thedamagetothemasonry-infilledreinforcedconcrete(RC)framebuildingsinCharikot,thecapitalcityofDolakhadistrictinNepal,duringthe2015April-to-MayNepalearthquakesequenceisreported.Mostofthesebuildingswerebuiltbytheownerswithlittlegovernmentalinspectionsregardingtheirstructuraldesignorconstructionalquality.Althoughtheygenerallyperformedbetterthanotherstructuralsystemssuchasstone-masonryhouses,theRCframessustainedextensivedamagerangingfromcrackingofinfilltocompletecollapse.Inparticular,eightofthe72inspectedRCframesalongsideanuphillstreetcollapsedindifferentways.Inadditiontotheun-engineerednatureoftheseRCframes,theircollapsecouldalsobeattributedtomultipletechnicalreasonsincludingtheeffectofterrain,thepoundingbetweenadjacentbuildingsandtheaccumulativedamageintheearthquakesequence.
简介:Theonlinesocialnetworks(OSNs)offerattractivemeansforsocialinteractionsanddatasharing,aswellasraiseanumberofsecurityandprivacyissues.Althoughcurrentsolutionsproposetoencryptdatabeforesharing,theaccesscontrolofencrypteddatahasbecomeachallengingtask.Moreover,multipleownersmayenforcedifferentaccesspolicytothesamedatabecauseoftheirdifferentprivacyconcerns.Adigitalrightsmanagement(DRM)schemeisproposedforencrypteddatainOSNs.Inordertoprotectusers'sensitivedata,theschemeallowsusersoutsourceencrypteddatatotheOSNsserviceproviderforsharingandcustomizetheaccesspolicyoftheirdatabasedonciphertext-policyattribute-basedencryption.Furthermore,theschemepresentsamultipartyaccesscontrolmodelbasedonidentity-basedbroadcastencryptionandciphertext-policyattribute-basedproxyre-encryption,whichenablesmultipleowners,suchastaggeduserswhoappearinasingledata,customizetheaccesspolicycollaboratively,andalsoallowsthedisseminatorsupdatetheaccesspolicyiftheirattributessatisfytheexistingaccesspolicy.Securityanalysisandcomparisonindicatethattheproposedschemeissecureandefficient.