IntroductionRelated work 2 Contents Publish/Subscribe middleware Conclusion and Future works

Introduction  Objectives  Research related to adaptive ontology middleware for diverse raw data in sensor networks  Topics related to our research  Context aware  Ontology  Middleware 3 Middleware OntologyContext aware Step 1 Step 2 Step 3

Introduction  Ontology  A data model that represents a set of concepts within a domain and the relationships between those concepts It is used to reason about the objects within that domain 4

Introduction  Context  any information that can be used to characterize the situation of entities.  Context-Awareness  Seeks to deal with linking changes in the environment with computer system 5 Input Information Output Information Context-Aware System General context - User situation - Physical situation - Computing system situation - etc.

Introduction  Middleware  The software that sits 'in the middle' between applications working on different operating systems  Function Support the standardized system service for diverse application Support environment to control diverse application Support the technology to efficiently use system resource 6 To begin with we should develop the middleware to send diverse sensing data to user application (Step 1)

Related work  Sensor middleware  The main purpose of middleware for sensor networks Support the development, maintenance, deployment, and execution of sensing-based application  This includes mechanism for Formulating complex high-level sensing task Communicating this task to the WSN Coordination of sensor nodes to split the task and distribute it to the individual sensor nodes Data fusion for merging the sensor readings of the individual sensor nodes into a high-level result Reporting the result back to the task issuer Etc.  Energy efficiency, robustness and scalability 7

Related work  Sensor middleware modules 8 User App #1User App #2User App #3 Context-Aware management component USN application service management component Meta-data management component Sensing-data management component Various query component USN gateway management component Server-sideIn-network Node App #1Node App #2Node App #3 In-network query component Sensor/driver management component Topology management component Sensor node monitoring component

Related work  Sensor middleware modules 9 Server-side (server)Description Various query componentA component to express various requirement of USN application service Sensing-data management component A component to efficiently store and manage sensing-data by time USN gateway management component A component to abstract the sensor nodes for the independent wireless communication between these nodes USN application service management component A component to independently assign and manage application service Meta-data management component A component to store information about other information Context-Aware management component A component to compare and analyze previous and current information for adapting them to the current user’s situation In-network (sensor)Description In-network query componentA query process component for information sharing between sensor nodes Topology management component A maintenance and management component of topology in sensor networks Sensor node monitoring component A monitoring component on the sensor node’s resource and neighbor Sensor/driver management component A sensor and driver control component

Pub/Sub middleware  Asynchronous messaging paradigm  where senders (publishers) of messages are not programmed to send their messages to specific receivers (subscribers)  Publisher Published messages are characterized into classes –Without knowledge of what (if any) subscribers there may be  Subscribers Express interest in one or more classes, and only receive message that are of interest –Without knowledge of what (if any) publishers there are.  Decoupling of publishers and subscribers Allow for greater scalability and a more dynamic network topology 10

Pub/Sub middleware  Publish/Subscribe architecture 11 Node App #1Node App #2Node App #3 Publish/Subscribe middleware TinyOS 1.x Architecture Radio CPU Sensor Message management Data management Service #1Service #2Service #N TopicPublish Subscribe

Pub/Sub middleware  Publish/Subscribe middleware module 12 Publish/Subscribe middleware Message management Topic Transmit the local topic to server by broadcasting Subscribe Receive the subscribe message from server Publish Transmit the publish message related to subscribe Data management Topic Manage the data collected from local sensors (e.g. Temperature, Lighte.etc) Publish Manage containing data related to the advertised topics Services AVG A service to average local or remote sensing data subscribed by server SUMA service to sum local or remote sensing data subscribed by server

Pub/Sub middleware  Publish/Subscribe middleware diagram 13

Pub/Sub middleware Frequency Range Processor Radio Transceiver Serial FlashRAM 2.4Hz ISM Band Atmel ATMega 128L TI2420 Atmel At45DB41B (512kB) 4K bytes Features BuzzerMicrophonePhotoregisterThermistor Description Mote/Board Connectors Programming PortData port USB ProgrammerIRIS, MICAz MICA2USB Wireless Modules ( MPR 2400) Sensor Board (MTS300) Gateways (MIB520) OS Cygwin Tinyos version 14

Pub/Sub middleware 1. Receive advertisement message of Node 1 2. Send the subscribe message of Node 1 3. Receive the sensing data of Node 1 4. Receive advertisement message of Node 2 5. Send the subscribe message of Node 2 6. Receive the sensing data of Node 1 & Node 2 15 ADV (Node 1 ) SUB(App #1) PUB(Node 1) PUB (Node 1 & 2) ADV(Node 2) SUB(App #2)

Conclusion & Future work  We implemented the publish/subscribe middleware  It is located on sensor nodes between TinyOS and application  It communicated by message (message-oriented communication)  User application can select the specific node for collecting sensing-data  Future work  Server-side Various query component  In-network Topology management component 16

Thank you 17