Presentation evrythng

A Model-Driven,
Component Generation
Approach for the WoT
University of Fribourg

Overview
• Vision
• Short Technological Background
• The xWoT
• A component approach for the xWoT
• Meta-Modeling
• The xWoT Compiler
• S2Mashup Editor
• Semantic Discovery for the xWoT
Université de fribourg | FACULTÉ des sciences | Andreas / Ruppen |
A Model-Driven, Component Generation Approach for the WoT
08/07/2015

INTRODUCTION
& Vision
08/07/2015

Vision
• Instead of finding better approaches on how to combine smart
devices we have to re-think how to build smart devices.
• The current WoT needs to be extended to take into consideration
algorithms and handle events gracefully.
• Re-usable and easy to deploy components, taking care of aspects like
events (and discovery in the future) are the way out of the “things-
crisis”.
• Adopt Model Driven Architecture.
• Allow Models to be enhanced semantically.
08/07/2015

BACKGROUND
Historical and Technological
08/07/2015

Software Components
• According to Cox the solution to the software crisis in the
early 80’s.
• A software component is a unit of composition with
contractually specified interfaces and explicit context
dependencies only. A software component can be
deployed independently and is subject to composition by
third parties. (Szyperski)
08/07/2015

Meta-Model
• Given
• α:S→M
• Then
• ∃ SUS1, SUS2 ∈ S|
α(SUS1) = α(SUS2)
⇏SUS1 = SUS2
08/07/2015

Meta-Model
• Given
• α′ : M → MM
• Then
• ∃ m1,m2 ∈ M | α′
(m1) = α′(m2) ⇏
m1 = m2
08/07/2015

The xWoT
An Extension for the WoT
08/07/2015

WoT Problems
• Data Integration: Treat Algorithms and other RESTful
services as first class citizens.
• Event Architecture: Define a common event architecture
suitable for a wide range of applications.
• Building Blocks: Introduce components as the building
blocks of the xWoT.
08/07/2015

Data Integration
• Mashups already rely on services like Facebook or
Twitter.
• How to turn a Book into a Smart-Book?
• Leveraging the power of established computational
resources to the WoT, e.g. Business Processes.
08/07/2015

Events
• Today: use of IoTaaS platforms like Xively.
• Problem: Smart-Devices are no longer WoT Compliant.
Instead the IoTaaS Platform is.
• Events must propagate in an (energy) efficient manner.
• WebHooks: spare events, alerting
• WebSockets: many events, live monitoring
08/07/2015

Components
• Hide the inner guts from clients.
• Define a clear interface for users (RESTful).
• Build reusable components.
• Use Meaningful URIs.
• Use Predictable URIs (plus HATEOAS)
08/07/2015

Formal Definition
• The extended WoT is a web made of sensors, actuators and tags forming
the classical WoT plus services respecting RESTful principles.
• The aim of the xWoT is to introduce a standard approach on how to design
the building blocks for novel applications and mashups exploiting the
capabilities offered by smart things and other virtual goods. To achieve this
goal, the xWoT introduces a component- based methodology which is
underlined by a meta-model guiding the developers during crucial
architectural decisions. Finally, since the architecture respects the xWoT’s
meta-model, component skeletons are generated out of the specifications.
08/07/2015

COMPONENTS
Reusable xWoT Components
08/07/2015

Corridor - ExampleUniversité de fribourg | FACULTÉ des sciences | Andreas / Ruppen |
08/07/2015

Expected Output
• One component representing the corridor.
• One component for each instantiated corridor.
08/07/2015

SmartDoor Component
http://service1.com/door/ GET
http://service1.com/door/oc/ GET / PUT
http://service1.com/door/oc/pub/ various
http://service1.com/door/lu/ GET / PUT
http://service1.com/door/lu/pub/ various
SmartCorridor
http://service2.com/corridor/ GET
http://service2.com/corridor/{id} GET
http://service2.com/corridor/{id}/oc GET / PUT
http://service2.com/corridor/{id}/oc/pub/ various
http://service2.com/corridor/{id}/lu/ GET / PUT

META-MODELING
The xWoT Meta-Model
08/07/2015

Partial xWoT Meta-Model
Virtual Entity
Resource
Actuator
Resource
Sensor
Resource
Service
Resource
1..*
Publisher
Resource
Context
Resource
Physical Entity
Entity
0..1 1
DeviceTag SensorActuator
1..*
08/07/2015

Full xWoT Meta-Model
Virtual Entity
Resource
Actuator
Resource
Sensor
Resource
Service
Resource
1..*
Publisher
Resource
Context
Resource
Physical Entity
Entity
0..1 1
DeviceTag SensorActuator
1..*
name: EString
method: MethodOperation
output: MethodOutput
input: MethodInput
Method
style: MethodStyle
MethodParam
style: MethodStyle
VEntityParam
name: EString
type: EString
Param
TEMPLATE
QUERY
MethodStyle
XMLJSON
MULTIPARTRELATED
FORM
NONE
MethodInput
XMLJSON
MULTIPARTRELATED
FORM
NONE
MethodOutput
GET
PUT
POST
DELETE
MethodOperation
0..* 0..*
0..*
08/07/2015

Smart Door Example (UC)
08/07/2015

Smart Door Example (HW)
08/07/2015

Smart Door Example (M)
08/07/2015

COMPILER
A Model Compiler for the xWoT
08/07/2015

Model Enhancer
• Since there is a one-to-one mapping from the Physical Entity to the
Virtual Entity, for each physical model, its virtual side can be
generated.
• The generated virtual side can be further refined manually.
• Takes as input an xWoT Model and generates a new, enhanced
xWoT Model.
• Where additional information is needed, the compiler asks for user
input.
08/07/2015

Smart Door Example (rev)
08/07/2015

Model Compiler
• Once the model finished, it can be compiled into code skeletons.
• The compiler takes care of:
• Resources hierarchy.
• Allowed Methods.
• It can generate:
• Python Code (Autobahn)
• Node.js
• Etc.
08/07/2015

Model Compiler
• Takes as input an xWoT model and automatically
generates a REST service for each component.
• Each components contains code skeletons to be filled in
by the developer.
08/07/2015

Reusability
• The Compiler takes care of:
• The reusability of the generated components.
• To create a new RESTful service for each Composite
(according to the composed flag).
• Of the Application Scenario Service
08/07/2015

Smart Room Example (UC)
08/07/2015

METHODOLOGY
08/07/2015

Three Steps
• Entity Modeling (blue)
• Data Modeling (green)
• Implementation (yellow)
08/07/2015

Methodology
Implement HTTP
Responses
Deﬁne Entity
Model Entity
Physical
2
Virtual
REST
Skeleton
Model
Physical Entity
Model
Virtual Entity
Reﬁne
Virtual Entity
Create Sever
Skeleton
Link Code to
Hardware
Build
Hardware
Model Representations
Create
XSD
Create Code
Artifacts
Model Database
Create
ERM
Forward
Engineer
DB
Create
Code
Artifacts
08/07/2015

S2Mashup
Smart, Semantic Mashup Editor

Ingredients
• Consumer friendly Mashup Editor (drag and drop).
• Include Semantics:
• Discovery.
• Late-Binding.
• (Semi)-Automatic-Binding.
• Write once, deploy everywhere.
08/07/2015

08/07/2015

DISCOVERY
A quick Outlook
08/07/2015

Requirements
• Implement a discovery mechanism respecting RESTful
principles (as far as applicable).
• Inject semantics into the discovery based on the meta-
model.
• Extend semantics depending on a situation’s needs.
• Adopt current standards (JSON-LD, Tuples)
08/07/2015

Limitations
• Implementation based on multicast/unicast between
devices.
• Limited to the multicast network boundaries.
• Startup a little wiggly.
08/07/2015

Demo
08/07/2015

CONCLUSION
& Outlook
08/07/2015

Benefits
• Allow fast prototyping.
• Support developers.
• Give end users the possibility to build re-usable mashup
applications.
08/07/2015

Future Work
• Bring the different projects together
• S2Mashup
• Semantics
• Discovery
• Meta-Model
• Propose a fully integrated tool for developers as well as
for end users to either create new smart Things or exploit
deployed ones.
08/07/2015

Presentation evrythng

More Related Content

Viewers also liked (6)

Similar to Presentation evrythng (20)

More from Andreas Ruppen (7)

Recently uploaded (20)

Presentation evrythng