An adaptive event-based system for anytime, anywhere, awareness services in online teamworks

Title:'An'Adaptive'Event-based'System'for'Anytime,'Anywhere,'Awareness'Services' in'Online'Teamworks' Vladi&Kolici,&Polytechnic&University&of&Tirana,&Albania&([email protected])'' Fatos&Xhafa,&Technical&University&of&Catalonia,&Spain&([email protected])&& Santi&Caballé,&Open&University&of&Catalonia,&Spain&([email protected])&& Leonard&Barolli,&Fukuoka&Institute&of&Technology,&Japan&([email protected])& ' & Abstract:' The&fast&development&in&mobile&technologies&IS&drastically&changing&the&way&people& work,&learn,&collaborate&and&socialize.&One&such&important&activity&that&has&emerged& and& is& being& consolidated& each& time& more& is& the& online& learning& through& virtual& campuses.& While& most& of& online& learning& services& are& at& present& offered& through& web-based& platforms,& due& to& ever-increasing& use& of& smart& devices& such& as& smartphones&and&tablets,&researchers&and&developers&are&paying&attention&to&exploit& the& advantages& of& mobile& systems& to& support& online& learning.& Specifically,& the& implementation& of& the& A3& paradigm:& Anytime,& Anywhere,& Awareness& –that& is,& notifying& users& about& ongoing& activity& in& their& online& workspace–& provides& various& advantages&to&online&learners&organized&in&online&teams.&In&this& paper& we& present& the&requirement&analysis,&the&building&blocks&of&the&architecture&for&efficient&eventbased&system&and&a&prototype&implementation&of&the&A3¶digm&that&adaptively& supports&the&online&collaborative&activity.& & Keywords':' Online&learning&;&collaborative&team&work&;&events&;&mobile&computing&;&awareness&;& & Short'Biographies' ' Vladi'Kolici'received&his&BS&and&MS&in&Telecommunication&Engineering&from'the&Polytechnic&University&of&Tirana&(PUT)& in&1997&and&2005,&respectively.&He'obtained&his&PhD&from&PUT&in&May&2009.&From&1997&to&2004,&he&was&a&Research& Associate,&from&2005&to&2011&he&has&been&a&Lecturer&and&at&present&he&is&Associate&Professor&at&the&Department&of& Electronics& and& Telecommunications,& Faculty& of& Information& Technology,& PUT.& He& is& teaching& several& courses& in& the& areas& of& wireless& and& mobile& networking,& P2P& systems& and& quality& of& services.& His& has& published& several& papers& in& international& and& national& conference& proceedings& in& the& areas& of& P2P& and& ad& hoc& networks.& His& research& interests& include&P2P&networks,&wireless&and&mobile&wetworks&and&highspeed&networks.' & Fatos&Xhafa&holds&a&PhD&in&Computer&Science&from&the&Department&of&Computer&Science&of&the&Technical&University&of& Catalonia&(UPC),&Barcelona,&Spain,&where&he&holds&a&permanent&position&of&Professor'Titular'(Hab.'Full'Professor).&He& was&a&Visiting&Professor&at&Birkbeck&College,&University&of&London&(UK)&during&academic&year&2009-2010&and&Research& Associate&at&Drexel&University,&Philadelphia&(USA)&during&academic&term&2004/2005.&&Prof.&Xhafa&has&widely&published&in& peer&reviewed&international&journals,&conferences/workshops,&book&chapters&and&edited&books&and&proceedings&in&the& field.& Prof.& Xhafa& has& an& extensive& editorial& and& reviewing& service& and& is& actively& participating& in& the& organization& of& several& international& conferences.& & His& research& interests& include& parallel& and& distributed& algorithms,& security,& optimization,&networking&and&distributed&computing.&More&information&can&be&found&at&http://www.lsi.upc.edu/~fatos/!' Santi&Caballé'holds&holds&Ph.D.&(2008),&Master's&(2005)&and&Bachelor's&(2003)°rees&in&Computing&Engineering&from& the&Open& University& of& Catalonia&(UOC).&His& teaching& activity& started& in& 2004& as& an& Assistant& Professor& at& the& department&of&IT,&Multimedia&and&Telecommunication&of&the&UOC,&where&he&became&Associate&Professor&in&2006&and& Academic&Director&of&the&Postgraduate&program&of&Software&Engineering&in&2010.&He&received&a&teaching&accreditation& as&Tenure-track&Lecturer&issued&by&the&Catalan&Government&(2008)&and&was&awarded&with&teaching&merits&for&the&period& 2005-2009& by& the& UOC.& He& is¤tly& teaching& and& coordinating& a& variety& of& on-line& courses& of& the& Bachelor& and& Master&in&Computing&Engineering&and&other&post-graduate&programs&in&the&areas&of&Software&Engineering,&Collaborative& Learning& and& Information& Systems.& He& is& also& supervising& several& Master& and& PhD& thesis& at& the& UOC.&His& research& interests&include&eLearning,&virtual&campuses,&distributed&computing,&Web-based&computing,&among&others.& ' Leonard' Barolli' holds& a& Ph.D.& degree& from& Yamagata& University,& Japan& in& 1997.& He& is& presently& a& Full& Professor& at& Department&of&Information&and&Communication&Engineering,&Faculty&of&Information&Engineering,&Fukuoka&Institute&of& Technology&(FIT).&Dr.&Barolli&was&an&Editor&of&Information&Processing&Society&of&Japan&(IPSJ)&Journal&and&has&served&as&a& Guest&Editor&of&many&International&Journals.&He&is&engaged&as&a&Program&Committee&(PC)&Member&in&many&International& Conferences.&&Dr.&Barolli&has&widely&published&in&Referred&Journals,&International&Conference&Preceedings&and&National& Workshops.&His&research&interests&include&high-speed&networks,&mobile& communication& systems,& ad-hoc& networking,& sensor& networks,& P2P& systems,& Quality& of& Service& (QoS),& traffic& control& mechanisms,& intelligent& algorithms,& network& protocols,&agent-based&systems,&grid&and&Internet&computing.&Dr.&Barolli&is&a&member&of&IPSJ,&Japan&Society&for&Fuzzy& Theory&and&Systems&(SOFT),&IEEE&Society&and&IEEE.& & 1.'Introduction'and'motivation' & A& new,& widespread& family& of& applications& has& emerged& as& a& combination& of& best& advantages&offered&by&mobile&computing&and&Cloud&computing&(also&referred&to&as& “mobile&cloud&computing”&[1]).&Indeed,&on&the&one&hand,&in&the&recent&years&we&have& seen&how&the&concept&of&mobile&device&has&considerably&evolved&towards&a&variety& of&applications,&including&more&applications&for&work&purposes.&The&frontier&between& computers&and&mobile& devices&is&each&time&more& blurred,&and&people&start&to& use& massively&new&smart&devices&that&can&carry&with&them&everywhere¬&only&as&means& of&communication&but&also&to&accomplish&tasks&online.&Staying&online,&connected&to& online&resources,&and&receiving&information,&from&different&channels,&in&an&intuitive& and& easy& way& enables& to& shorten& considerably& the& response& time;& it& is& also& an& effective& way& to& request& help& and& support& from& others.& For& instance,& in& online& learning,&scaffolding&is&very&important&to&learners,&either&in&a&virtual&classroom&or&a& virtual& workspace& of& an& online& team.& Traditionally,& scaffolding& through& web-based& online&applications&might¬&have&the&desired&effect&given&that&considerable&time& could&pass&from&the&moment&when&a&help&or&support&request&is&issued&to&the&time&it& is&done&effective.&& & By& combining,& Web-based& and& Cloud& based& technologies& with& the& use& of& mobile& devices,& the& online& learning& and& collaborative& activity& can& be& much& more& timely,& efficient& and& adaptive& [2].& In& particular,& scaffolding& can& be& a& much& more& effective& way&of&accomplishing&learning&activities&because&learners&can&request&support&at&any& time&and&other&learners&can&scaffold&their&team&mates&at&any&time,&anywhere&due&to& the& awareness& services.& & Currently,& we& also& see& how& social& networks& have& been& widely& used& for& such& purpose,& by& adapting& to& this& idea,& that& is,& using& social& networking& properties& in& support& to& learners.& For& instance,& one& such& feature& explored& is& the& emotional& awareness& as& the& emotional& support& is& an& important& aspect&of&social&networking.&&Several&studies&from&mobile&learning&domain&(e.g.&[3],& [4]),&have&pointed&out&that&using&mobile&devices&on&online&learning&can&contribute&to& increasing&the&perception&of&social&connectedness&of&learners&yielding&to&emotional& well-being& among& learners& and& reducing& the& frustration& often& produced& by& the& isolation&in&online&virtual&classrooms.& & The&implementation&of&the&A3¶digm:&anytime,'anywhere,'awareness&would&make& online&systems&more&adaptive,&because&the&online&learners&can&adapt&their&activity& and& needs& to& those& of& others& “as& they& go”.& Being& anytime,& anywhere& and& aware& about& what& happens& in& online& setting& is& therefore& a& constant& demand& in& online& collaborative&work.&In&this&paper,&we&discuss&about&this¶digm&focused&on&online& teams,&describing&in&a&practical&way,&how&the&team&communication&can&significantly& improve&by&using&mobile&devices.&Starting&from&a&bottom-up&approach&we&describe& how& the& A3& paradigm& can& be& applied& to& different& mobile& team& working& scenarios& [5].&& Our& approach& is& based& on& the& definition& and& use& of& events& linked& to& state& changes& of& the& objects& in& the& common& learning& workspace.& The& events& are& then& processed&and&sent&to&mobile&clients&for&consumption&following&the&A3¶digm.& & In& the& current& state& of& the& art& of& the& event-based& system,& we& can& find& many& interesting&methodological&proposals&for&designing&event-based&mobile&applications.& Thus,&the&authors&in&[6]&proposed&an&event-based&coordination&approach&to&execute& process& oriented&composite& applications,& with& components& on& server& and& at& the& client& site.& Another& interesting& work& in& this& context,& but& rather& focused& on& task& oriented& team& collaboration,& deals& with& notification& and& awareness& synchronizing& task-oriented&collaborative&activity&[7].&The&authors&in&[8]&proposed&the&use&of&XML& messaging& for& mobile& devices& for& effectice& communication.& Different& from& these& approaches,& in& our& approach,& the& objective& is& to& make& the& system& as& simple& as& possible,&so&even&it's&possible&to&adapt&the&approach&in&[6],&we&want&to&use&existing& communication& channels& between& clients,& widely& used& by& users& in& their& social& networking&life,&without&the&need&of&use&new&protocols.&&Additionally,&we&consider& that& in& the& teamwork,& people& prefer& working& together& using& exiting& tools& and& our& research& aims& to& study& how& mobile& devices& can& be& integrated& into& existing& online& applications.&& & As& per& the& use& of& protocols,& again& the& idea& is& not& to& use& any& specific& protocol& to& deliver&messages,&but&instead,&to&use&existing&ones&building&a&gateway&between&our& platform&and&the&delivery&platform.&In&all,&our&aim&is&to&build&a&new&layer&integrated& onto&existing&teamwork&systems,&which&can&be&also&possible&to&be&used&in&another& kind& of& systems,& which& need& to& spread& messages& and& notifications& to& groups& or& particular& users.& Taking& into& account& the& current& convergence& between& computers& and&mobile&devices,&the&system&should&be&used¬&only&to&add&mobile&capabilities&to& existing&systems,&but& also& to&add&a&complete&delivery&system& to& those&that&do¬& have&such&delivery&services,&namely,&A3&services.& & Due&to&the&computational&limitation&of&mobile&devices,&the&extension&of&web-based& systems&to&support&also&mobile&clients&require&specific&design&and&implementation&to& make&the&system&usable,&efficient&and&scalable.&In&this&work&we&use&an&event-based& approach& to& extend& web-based& applications& to& support& Anytime,& Anywhere,& Awareness&in&online&teams.&It&should&be¬ed&that&the&A3¶digm&is&meant¬& only&as&informing&channel&but&also&for&social&support&and&scaffolding.&The&key&feature& here&is&the&definition&of&events&linked&to&state&changes&of&the&objects&in&the&common& workspace.& The& events& are& then& processed& and& sent& to& mobile& clients& for& consumption.& & Goals:&The&main&design&goals&of&an&adaptive&A3¶digm&for&onlione&collaborative& setting&can&be&listed&as&follows:&& & -&Simplicity:&reusing&existing&communication&channels&and&technologies.& -&High'availability:&building&a&system&that&relies&on&technologies&that&can&support&high& availability&by&default.& -&Scalability:&taking&into&account&in&the&design&that,&without&a&big&effort,&the&system& can&scale&efficiently&to&more&users&and&larger&&amounts&of&online&teamwork.& -& Modularity:& choosing& a& software& architecture& that& guarantees& that& the& different& parts& can& be& improved,& changed& or& new& ones& added& without& affecting& the& other& parts&of&the&system.& -&Independency' from' devices:& again& the& modular& software&architecture&will&help& to& add&new&devices&without&big&efforts.& -&Security:&in&the&event-based&system&we&need&to&ensure&that&the&system&will&take& into&account&the&needed&security&features.& -& Openness:& building& an& open& system& is& a& key& requirement& nowadays& to& facilitate& integration&and&inter-connection&with&other&systems&that&use&or&need&event-based& notifications.& & The& rest& of& the& paper& is& structured& as& follows.& In& Section& 2,& we& describe& the& main& concepts& and& requirements& upon&which& our& proposal& relies.& Then,& we& outline& the& design& of& the& event& management&in& Section& 3.& In& Section& 4,& we& introduce& the& implementation& issues& and& prototyping& in& order& to& demonstrate& how& the& event& management&could&be&done.&In§ion&5,&we&present&how&the&system&can&be&fit&into& an&eLearning&scenario.&Finally,&we&present&some&conclusions&and&an&outlook&to&future& research&opportunities&in&Section&6.& & & 2.'Main'concepts'and'requirements' ' &&&&& We&follow&the&transactional&model&of&communication&[9]&where&the&source&sends&a& message,& through& a& channel,& to& the& receiver&and& a& feedback& comes& back& to& the& sender:& & & & Then,&we&transform&it&into&the&model&where&an&event&originates&a&message&that&is& sent,&through&a&channel&(SMS,&Twitter,&email,&etc.)&to&a&user.& & Message Sender Receiver Feedback & Once&the&message&is&received,&the&user&can&take&some&further&actions&in&order&to&get& more&information&relevant&to&an&object,&a&user,&etc.&Let&us&see&now&more&in&detail& these&steps.& & Event&is&the&main&concept&in&our&system.&We&define&an&event&as&the&change&of&one&of& the& attributes& of& an& object.& Objects& are& entities& that& have& properties& that& can& be& observable.& & These& attributes& can& change& overtime,& but& while& they& remain& the& unchanged,&they&define&one&possible&state&of&the&object.&&In&our&system&each&object& has& associated& a& process,& called& observer,& which& will& detect& the& changes& in& the& objects’&state.&In&order&to&group&all&the&objects&that&are&related&according&to&some& coherent& criteria,& we& have& defined& the& notion& of& context.& Also& each& object& has& associated&one&or&more&possible&actions,&namely&retroactions,&which&are&actions&that& users&can&further&take&with&the&system&when&a&message¬ification&is&received&from& the&system.&& & In&the&system,&we&have&the&targeted&users&–the&ones&that&will&receive&the&messages.& In&many&applications,&however,&we&may&have&a&collection&of&users,&joined&together&in& a&group.&In&the&former&case,¬ifications&are&sent&to&a&particular&user&while&in&the& later,&the&messages&are&sent&to&all&users&belonging&to&the&same&group.&We&can&talk&in& this& case& about& group& notification.& This& introduces& the& concept& of& subscription.& A& subscription'is&the&link&between&particular&users,&or&groups&of&users,&and&the&events& that& produce& the& objects& due& to& changes& in& their& state.& In& case& of& a& group& subscription,& sending& a& message& to& the& group& means& sending& a& message& to& each& member&of&the&group.&Unsubscription'will&happen&when&a&user,&or&a&group&of&users,& cancel&a&subscription.&& & The&action&of&sending&a&message&is&called¬ification.&Messages&can&vary&depending& on& the& communication& channel& we& use,& so& we& can& talk& about& SMS,& MMS,& email,& tweet,&etc.,&messages.&&Messages&can&be&sent&in&two&modes:&push&and&pull.&In&a&push& mode,&the&user&will&receive&the&message&as&soon&as&the&message&becomes&available.& In& pull& mode,& the& user& will& only& receive& the& message& through& queries& for& new& messages.& The& former& is& a& synchronous& transmission& mode& while& the& later& is& an& asynchronous&transmission&mode.& & We&sum&up&the&key&concepts&of&the&event-based¬ification&system&in&Table&I.& & Table'I:'Concepts'and'terminology.' Event& The&change&in&one&of&the&attributes&of&the&object.& Attribute& Property&of&the&object&that&can&be&observed.& Object& Things&that&has&properties&that&can&be&observable.&&& Message Event User More info Observer& Process&that&detects&events.& Context& Group& of& objects/properties& that& are& coherently& related.& Retroactions& Actions& that& users& can& take& in& order& to& interact& with&the&objects&/&the&system.& User& Person&that&use&the&system.& Group& User&association.& Message& Information&that&a&user&receives.& Notification& Action&of&sending&a&message.& State& Values&of&the&objects&attributes&in&a&certain&period& of&time.& Subscription& Link& between& users,& o& groups& of& users,& and& the& events& that& produce& the& changes& in& objects’& states.& Unsubscription& Cancelation&of&the&subscription.& Push&mode& Mode& of& sending& a& message& when& it& becomes& available,&once&an&event&happens.& Pull&mode& The&message&is&sent&due&users’&queries&about&new& messages.& & & The&analysis&led&to&the&entity&diagram&shown&in&Figure&1.& & Figure'1:'Entity'diagram'of'the'event-based'system' && & 3.'Design'of'the'event'management' & The& event& management& model& includes& management& of& users,& subscriptions& and& events&(see&Figure&2&for&a&graphical&representation).& & & Figure'2:'System'model' & As&can&be&seen,&the&system&is÷d&into&two&main&building&blocks&or&modules:& & 3.1'User'management'and'interaction'module:&In&this&module&we& manage&all&the& users,& groups,& events,& objects& and& subscriptions& /& un-subscriptions.& We& take& into& account&that&third&parties&system&could&use&our&system.& &&&&& 3.2'Core'system'module:&In&this&module,&we&manage&all&the&processes&that&observe& the&objects,&in&order&to&detect&events,&and&generate¬ifications&to&the&groups&or& particular&users.&Again,&we&take&into&account&that&third&parties&can&use&this&module&of& our& system.& In& this& later& case,& it& is& upon& third& parties& systemsto& take& the& responsibility&to&observe&the&objects&and&send&to&our&system&all&the¬ifications.& & In&terms&of&system&architecture,&the¬ification&system&is&organized&into&following& layers.& & Client'layer' This&layer&interacts&with&the&system.&Users&use&existing&client&interfaces&to&interact& with& the& system& depending& on& the& implementation& of& the& presentation& layer.& The& client&interface&can&be&of&various&forms:&from&a&web&browser&(in&order&to&interact& with&the&presentation&layer&in&charge&of&manage&the&accounts)&to&a&SMS&client&that& shows&the&messages&sent&by&the&system&to&the&user.& & Presentation'layer' This&layer&is&in&charge&of&interacting&with&clients.&&We&have&a&variety&of&presentation& layers:&web,&wap,&SMS…,&one&for&each&client&layer.&Also&we&have&defined&an&API&in& order&to&be&used&by&third&parties.&This&API&offers&the&possibility&to&users&to&subscribe& and&unsubscribe&and&also&to&do&queries&to&the&system&(especially,&for&the&pull&mode).& Additionally,&in&this&layer&we&have&designed&also&the&packages&that&are&used&to&send& messages.& Depending& on& the& preferred& communication& channel,& we& can& find& SMS& connections,&twitter&account,&email&account…etc.& & Business'layer' This&layer&implements&all&the&logics&of&the&application&by&carefully&implementing&the& observer& objects,& the& subscriptions& as& well& as& the& mapping& of& groups/users& to& subscribed& events.& We& implement& the& observer&so& that& the& processes& that& are& constantly& observing& the& objects& in& order& to& detect& events,& and& the& dispatcher& processes& in& charge& to& deliver& the& message(s)& to& the& corresponding& groups/users& once&an&event&is&detected.&Each&time&a&new&event&is&detected&by&the&observer,&a&new& message&is&queued&into&a&messaging&queue&(see&Figure&3).&In&order&to&simplify&the& notification& processes,& the& queue& manages& only& “generic”& users& messages,& this& means& that& messages& to& groups& are& converted& into& users& messages& as& well.& & The& dispatcher&is&then&the&process&in&charge&of&the&delivery&and&applies&the&retry&policy&if& a&message&is¬&delivered&to&its&destination.& ' Integration'layer' This&layer&is&in&charge&of&integrating&data&layer&and&business&layer,&that&is,&the&data& layer&interaction&with&the&business&layer&and&the&IO&layer.& ' IO'Layer' In& this& layer& we& implement& the& data& persistence& chosen& to& store& all& the& system& information.& & & & Figure'3:'Message'dispatcher'and'observer' The&diagram&of&Figure&4&illustrates&the&architecture&described,&following&a&standard& layered&architecture.& & & Figure'4:'System'architecture' & 4.'Implementation'issues,'prototyping'and'evaluation' ' In& order& to& achieve& scalability& and& high& availability,& we& choose& first& of& all& HTTP& protocol.&With&a&combination&of&load&balancing&and&web&server&nowadays&both&goals& can&be&reached&easily.&In&order&to&ensure&the&same&flexibility&on&data&persistence,&we& choose&MongoDB.&&On&presentation&layer&we&develop&the&following&interfaces:& ' Web'admin' This& interface& allows& the& management& of& users,& events& and& subscriptions.& In& the& prototyping&there&was&a&unique&interface&without&authorization&and&authentication.& & The&prototyping÷s&this&interface&into&three&blocks:& - Users:&in&order&to&manage&users&and&groups& - Warnings:&in&order&to&manage&events,&objects,&context&and&retroactions& - Subscriptions:& in& order& to& manage& users& and& groups& subscriptions& and& unsubscriptions.& & Mobile'interface' This& interface& enables& users& to& receive& messages& on& their& mobile& devices& and& do& some&actions&at&their&end.&& & The&prototype&has&the&following&interfaces:& & - Pull:& In& order& to& manage& pull& messages& users& will& be& able& to& activate& reception& of& single& messages& or& messages& between& any& two& dates.& Activating& a& pull& mode& message&means&that&the&user&will&receive&the&message&through&the&channel&that&was& defined&on&the&event&action.& - Also,&we&implemented&an&interface&to&receive&an&SMS&with&a&link&in&order&to&check& the& pull& that& needs& to& be& activated& between& two& dates.& This& interface& doesn’t& activate&the&messages&but&just&visualize&them.& - Mobile:&as&an&example&of&mobile&interfaces&the&prototype&offers&an&interface&to&view& a&message&still&to&be&delivered,&all&the&pull&messages&between&two&dates&as&well&as& historical&information.& - All&the&messages&show&the&retroaction&that&the&user&can&do&on&them.&