SW-WoT

SW-WoT is a University Project for the Semantic Web exam. It allow to semantically discover the things described by a WoT thing description (TD). It's composed by 3 sub-modules:

core: contains the core functionality of SW-WoT, like things validation. Moreover this module contains two ontology: WoT and HomeOnto. The last one, is a custom ontology for describe some smart appliance in terms of WoT concept. HomeOnto is not to be considered a valid ontology for the description of Smart Applicance, it is only an example to show the potential of such an approach. (see the section of possible future works)
semantic-directory: allow to register thing descriptions and search for it using SPARQL query.
discovery-gateway: allow to make advanced search, like automatic collection of data retrieved from things. (e.g. all temperature values from temperature sensors).

Installation

The project could be open using Intellij that supports Kotlin very well. The main libraries used are: Jena and Vertx.

Moreover, in order to parse JSONLD-1.1 thing description format, its required to install Ruby on Rails on system and setup a configuration file for semantic-directory module:

{
  "host": "0.0.0.0",
  "port": 10000,
  "jsonld": {
    "type": "ruby",
    "ruby_exec": "ruby",
    "script": "semantic-directory/rubyjsonld/jsonld_rdf.rb"
  },
  "thing_folder": "semantic-directory/src/main/resources/things"
}

host and port allow to configure the semantic directory webservice;
jsonld allow to configure the parser for JSONLD-1.1.
- type defines which parser to use. Now, only ruby is supported.
- ruby_exec defines the ruby executable path. If the ruby path is added to PATH variable, don't change this value.
- script defines the ruby's script to use for parse the JSONLD-1.1.
thing_folder its an optional parameter. Allow to define a folder from which to load some thing descriptions at boot.

Usage

The project contains another module called scenarios that contains some useful examples of how to use the system.

How to start the semantic directory? ( after right setup of the configuration file in the resources)

val config = JSONObject(Source.readFromResource("directory-config.json"))
val jsonLdParser = JSONLDParserFactory.fromJson(config.getJSONObject("jsonld"))!!
val parser = TDParser(jsonLdParser = jsonLdParser)
val tdd = ThingDescriptionDirectory()
val restVerticle = RestApiSemanticDiscovery(
            tdParser = parser,
            thingDescriptionDirectory = tdd,
            host = config.getString("host"),
            port = config.getInt("port"))

val vertx = Vertx.vertx()
vertx.deployVerticleAwait(restVerticle)

Optionally, inside scenarios folder there is two utility bootstrap method for semantic directory:

// Start the semantic directory using the config file in resources (directory-config.json)
Bootstrap.defaultBoot(/*optionally, some thing description in json*/)

// Start the semantic directory specifing a config file
Bootstrap.bootSemanticDirectory(File(/*..*/), /*optionally, some thing description in json*/)

How to create a semantic gateway for advanced search?

// need to specify host and port where semantic directory is running
val discovery = DiscoveryGateway.fromDirectory("localhost", 10000)

How search some things?

e.g. collect some values from things

// this search things and collect data on specific property
val query = thingCollectQuery {
    filter {
        canSense { FeatureProperty.Temperature }
    }
    collectOn { FeatureProperty.Temperature }
}
discovery.collectData(query).mapNotNull { it.asDouble() }.average()

e.g. only discover things

val query = thingQuery { 
    canSense { 
        feature { FeatureProperty.AmbientTemperature }
        feature { FeatureProperty.AmbientHumidity }
    }
    canActOn { 
        FeatureProperty.AmbientTemperature
    }
}
val things = discovery.searchThings(query)

Possible Improvements

align WoT ontology to SAREF ontology and describe the smart appliances in terms of both instead of my custom Home-WoT ontology;
add support for dynamic discovery (e.g. find things that perceive a temperature > 20)
- actually the system allow to collect data. This functionality could be used to achieve dynamic discovery
improve the architectural layer of WoT that allow to achieve operational interoperability. Actually there is a mock implementation of the WoT stack inside ConsumedThing.kt
allow to retrieve the things by id through semantic directory web service using a path like: /td/{id}

petretiandrea/sw-wot

SW-WoT

Installation

Usage

Possible Improvements