1. TIBS Tractable Information Dissemination with Linked Data and Opportunistic Transfer 溫智宇 (Jack Wen), 周逸凡 (Ivan Chou), John K. Zao NCTU Pervasive Embedded Technology (PET) Lab Presented at OpenISDM Project Meeting 2015/03/20

2. Rationale  Disseminate crucial information to the public in emergency situations  Hold people accountable for their use of disseminated information Examples :  Structural plans of private homes  Personal information of victims and survivors

3. Goals  Replace Proactive Authentication & Authorization with Retrospective Audit of information dissemination  Cross domain information transmission detection  Low overhead in network traffic  High trace information send back rate

4. Approach  Make the information dissemination traceable in distributed environment and use  Data transfer records (tags) in RDF format are generated when information is received by mobile devices.  Tags are sent back to TIBS POS (Point of Service) Nodes when device move close to POS and receive beacon signals.  RDF tags are aggregated into a distributed Linked Data Repository maintained by TIBS infrastructure.

5. Architecture Tag Repository Information Repository Interface Server POS Interface Server  Push document to POS POS  Push document to mobile device  Broadcast beacon in fixed interval  Insert tag to repository : Info Dissemination : Beacon Broadcast : Tag Propagation PuSH disaster information network POS peer-to-peer wireless network Wireless access point network Mobile peer-to-peer wireless network Linked Data move

6. Design  Tag RDF Schema TransportSession  isTransportSessionOf ：此 Session 傳送哪份文件  hasSource ：文件的發送端 Device  hasDestination ：文件的接收端 Device  transportTime ：傳送時間 Document  hasTransportSession ：所有傳送此文件的 Session  belongsTo ：此文件所屬 Domain  hasAuthor ：此文件的作者 Device  belongsTo ：此 Device 所屬 Domain  Person ：此 Device 擁有者 Person  belongsTo ：此人所屬 Domain

7. Design  Tag → Linked Data → Trace POS Linked Data Repository Trace Server insert SPARQL query Result

8. Design  Protocol  Document/Tag transmission  Publish/Subscribe over opportunistic infrastructure  Beacon mechanism  Broadcast by POS  Tags are sent back to POS when device receive beacon signals  Resource saving: beacon TTL = 1  Tag aggregation  Combine tags in one transmission  If device get beacon in high frequency, then randomize the probability of tag transmission.  Tag offloading  Offload tags to neighbor node  Happens in  Low power mode 、 Isolated for a long time

9. Implementation  Tools Used  Haggle  Allows mobile devices to exchange content directly among themselves when they happen to come in close range contact.  Virtuoso Server  A middleware and database engine hybrid that combines the functionality of a traditional RDBMS, ORDBMS, virtual database, RDF, XML, free-text, web application server and file server functionality in a single system.  Gephi  An interactive visualization and exploration platform for all kinds of networks and complex systems, dynamic and hierarchical graphs.

10. Implementation  Software Modules PuSH Virtuoso SPARQL Haggle RDF file POS Server Query /Insert TAG RDF file Virtuoso PuSH SPARQL RDF file share API IS Server OS(Linux OS) JSON file RDF/ JSON translator OS(Android) Haggle Application User Manager User Interface Mobile Device Linked Data Repository Tag Generator Tag Transmission Control

11. Demonstration  Information Publishing  IS Server publishes documents(d1, d2) to POS1 by wired  Information Sharing  POS2/3 get documents from POS1  M2 gets document d1,d2 from POS3, M2 gets document d2 from POS3.  Then M1 gets document d1 from M2  Tag Generation  M1 generates 2 tags(d1:POS2 → M1, d2:M2 → M1)  M2 generates 2 tags(d1:POS3 → M2, d2:POS3 → M2)  Tag Transmission and Aggregation  Assume M1 in low power situation. Tags on M1 offload to M2  Making tag aggregation on M1 before offload to M2  Assume M2 gets beacon from POS2. M1 send all(4) tags back to POS2.  Making tag aggregation on M2 before send back to POS2  Tag Tracing  Trace the path of how M1 got the document d2

12. Tag file Content <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:j.0="http://pet.cs.nctu.edu.tw/ontology/openisdm/infoflow#" > D2 1426831511035 3c59a621-3ec7-4975-a368-affe404880ca person15 U122910432 Tax ID D1

13. Tag file Content Tb18 b0:ba:8a:10:06:9d MAC address Ph6 8a:cb:d1:f7:d4:06 MAC address person87 B194508653 Tax ID

14. Query Tag content from virtuoso DB by SPAQUL select ?doc_UUID from where { ?doc_UUID infoflow:hasTransportSession ?o } select ?tag_UUID from where { doc_UUID infoflow:hasTransportSession ?tag_UUID } select ?source_device from where { ?tag_UUID infoflow:hasSource ?source_device } select ?des_device from where { ?tag_UUID infoflow:hasDestination ?des_device } select ?trans_time from where { infoflow:hasOccurAt ?trans_time } //Set DeviceInfo List(from Source) String pre_property = "http://pet.cs.nctu.edu.tw/ontology/openisdm/infoflow#"; strselectTag = "prefix infoflow: select ?device " + " from where { ?s infoflow:hasSource ?device }"; System.out.println(strselectTag); Query selectTag = QueryFactory.create(strselectTag); VirtuosoQueryExecution vqeTag = VirtuosoQueryExecutionFactory.create(selectTag, setPOS); ResultSet rsTag = vqeTag.execSelect(); vqeTag = VirtuosoQueryExecutionFactory.create(selectTag, setPOS1); rsTag = vqeTag.execSelect(); while(rsTag.hasNext()) { QuerySolution qs = rsTag.nextSolution(); RDFNode rn = qs.get("device"); String id = rn.toString();//source_device id...

15. Demonstration  Trace graph

16. Conclusion  Contribution  Built an information dissemination prototype system with traceability  Using RDF format to define tag schema, then construct a linked data graph by tags for tracing.  Design an effective protocol for tag transmission  Future work  Improve the mechanism of the topic selection by LBS  Information dissemination path recovery in the situation of missing some tags