Ensemble-oriented programming of self-adaptive systems - Michele Loreti

Ensemble-oriented programming of self-adaptive
systems
Michele Loreti
Dipartimento di Statistica, Informatica, Applicazioni
Universit`a degli Studi di Firenze
AWASS 2013, Lucca, June 24-28, 2013
www.ascens-ist.eu

Ensemble-oriented programming of self-adaptive
systems: the E-Vehicle Case Study
Michele Loreti
Dipartimento di Statistica, Informatica, Applicazioni
Universit`a degli Studi di Firenze
AWASS 2013, Lucca, June 24-28, 2013
www.ascens-ist.eu

Outline. . .
Motivations;
Michele Loreti 2

Outline. . .
Motivations;
E-Vehicle Case Study: a short overview;
Michele Loreti 2

Outline. . .
Motivations;
Basic ingredients of:
Michele Loreti 2

Outline. . .
Motivations;
SCEL, a Service Component Ensemble Langugage;
Michele Loreti 2

Outline. . .
Motivations;
jRESP, a framework for executing SCEL applications in Java;
Michele Loreti 2

Outline. . .
Motivations;
jRESP, a framework for executing SCEL applications in Java;
E-Vehicle Case Study in SCEL and jRESP: a tentative roadmap.
Michele Loreti 2

Challenges of Ensembles Programming
Michele Loreti 3

Ensembles are software-intensive systems featuring
massive numbers of components
complex interactions among components, and with other systems
operating in open and non-deterministic environments
dynamically adapting to new requirements, technologies and
environmental conditions
From the ﬁnal report of: IST Coordinated Action InterLink [2007].
Michele Loreti 3

Challenges for software development for ensembles
Michele Loreti 3

the dimension of the systems
Michele Loreti 3

the need to adapt to changing environments and requirements
Michele Loreti 3

the emergent behaviour resulting from complex interactions
Michele Loreti 3

the emergent behaviour resulting from complex interactions
the uncertainty during design-time and run-time
Michele Loreti 3

Component Ensembles and Awareness
Michele Loreti 4

Components and Ensembles
Service components (SCs) and service-component ensembles (SCEs)
permit to dynamically structure independent, distributed entities that can
cooperate, with diﬀerent roles, in open and non-deterministic environments
Michele Loreti 4

Awareness
Awareness of Service Components is achieved by
Michele Loreti 4

Awareness
equipping SCs with information about their own state
Michele Loreti 4

Awareness
enabling SCs to get information on their working environment
Michele Loreti 4

Awareness
allowing SCs to use this information for restructuring and adapting
Michele Loreti 4

Awareness
allowing SCs to use this information for restructuring and adapting
Awareness makes SCs adaptable, connectable and composeable.
Michele Loreti 4

Case study: E-Vehicle Case Study
Michele Loreti 5

We consider a car pooling system where motorized mobility for users and
privately owned vehicles have to be coordinated in order to satisfy user
requirements and to guarantee an (possibly) optimal allocation of
resources.
Michele Loreti 5

We consider a car pooling system where motorized mobility for users and
privately owned vehicles have to be coordinated in order to satisfy user
requirements and to guarantee an (possibly) optimal allocation of
resources.
We will use SCEL to specify system behaviour while jRESP, its runtime
environment, will be used to develop a prototype implementation in Java.
Michele Loreti 5

E-Vehicle Case Study. . .
Michele Loreti 6

In the E-Vehicle Case Study the following entities cooperate:
Michele Loreti 6

users;
Michele Loreti 6

users;
User:
A user is an active unit of the system. Given its daily calendar of activities
a user:
plans its journey
books parking lots/charging stations
Michele Loreti 6

users;
User:
A user is an active unit of the system. Given its daily calendar of activities
a user:
plans its journey
books parking lots/charging stations
this task is performed in collaboration with the associated vehicle.
Michele Loreti 6

users;
vehicles;
Michele Loreti 6

users;
vehicles;
Vehicle:
A vehicle can:
move towards destinations,
use the vehicle travel planner to plan the journey,
book parking lots and charging stations.
Michele Loreti 6

users;
vehicles;
A vehicle also monitors:
the current traﬃc and road feasibility,
fuel consumption,
and parking lot/charging station availability.
Michele Loreti 6

users;
vehicles;
parking lots;
Michele Loreti 6

users;
vehicles;
parking lots;
Parking lots
A parking lot is an infrastructure unit of the system:
Michele Loreti 6

users;
vehicles;
parking lots;
Parking lots
It can be booked (and unbooked) by vehicles.
Michele Loreti 6

users;
vehicles;
parking lots;
Parking lots
It can be booked (and unbooked) by vehicles.
A single parking lot can be booked by a single vehicle at a time.
Michele Loreti 6

users;
vehicles;
parking lots;
charging stations.
Michele Loreti 6

users;
vehicles;
parking lots;
charging stations.
Charging stations:
A charging station is an infrastructure unit of the system:
Michele Loreti 6

users;
vehicles;
parking lots;
charging stations.
Charging stations:
It is used by electric vehicles in order to recharge their batteries.
Michele Loreti 6

users;
vehicles;
parking lots;
charging stations.
Charging stations:
A single charging station can be booked by a single vehicle at a time.
Michele Loreti 6

users;
vehicles;
parking lots;
charging stations.
Charging stations:
A single charging station can be booked by a single vehicle at a time.
Similar to the booking of parking lots, it is usually possible for vehicles
to book a charging station in advance.
Michele Loreti 6

2
Main Success Scenario
P1
P2
P3
P4
P5
POI1
POI2
POI3
POI4
POI2
POI1
POI3
Calendar
9:00
10:00
12:00
14:00
16:00
POIj = j-th point of interest Pi
P1
= i-th parking lot
Michele Loreti 7

Programming Ensembles. . .
Michele Loreti 8

SCEL is a speﬁciation/programming language equipped with
Michele Loreti 8

programming abstractions necessary for
directly representing Knowledge, Behaviors and Aggregations according
to speciﬁc Policies
naturally programming interaction, adaptation and self- and context-
awareness
Michele Loreti 8

programming abstractions necessary for
directly representing Knowledge, Behaviors and Aggregations according
to speciﬁc Policies
naturally programming interaction, adaptation and self- and context-
awareness
linguistic primitives with solid semantic grounds
To develop logics, tools and methodologies for formal reasoning on
systems behavior
to establish qualitative and quantitative properties of both the
individual components and the ensembles
Michele Loreti 8

SCEL: programming abstractions
The Service-Component Ensemble Language (SCEL) currently provides
primitives and constructs for dealing with:
Michele Loreti 9

1 Knowledge: to describe how data, information and (local and global)
knowledge is managed
Michele Loreti 9

2 Behaviours: to describe how systems of components progress
Michele Loreti 9

3 Aggregations: to describe how diﬀerent entities are brought together
to form components, systems and ensembles
Michele Loreti 9

3 Aggregations: to describe how diﬀerent entities are brought together
to form components, systems and ensembles
4 Policies: to model and enforce the wanted evolutions of computations.
Michele Loreti 9

A SCEL component
Knowledge
K
Processes
P
I Interface
Π
Policies
Michele Loreti 10

A SCEL component
Knowledge
K
Processes
P
I Interface
Π
Policies
Component interface provides information about the component itself.
This information is rendered as a set of attributes whose values can be
derived from the knowledge.
Michele Loreti 10

Predicate-based ensembles
In order to guarantee the maximum degree of ﬂexibility, ensembles are
rendered in terms of predicate-based communication primitives that select
the targets among those enjoying speciﬁc properties.
Michele Loreti 11

E-Vehicle Case Study (in SCEL). . .
Michele Loreti 12

9
Parking Lots close to
POIs as Ensembles
POI1
POI2
POI3
POI2
POI1
POI3
Calendar
9:00
10:00
12:00
14:00
16:00
P1
P2
P3
P5
ATTRIBUTES
●
type: parking lot component
●
position: position of the park
●
...
Michele Loreti 12

Michele Loreti 13

jRESP
A Run-time Environment for SCEL Programs
Basic design principles. . .
1 no centralized control
2 heavy use of recurrent patterns to simply the development of speciﬁc
knowledge
a single interface that contains basic methods to interact with
knowledge
policies
based on the pattern composite (policies are structured as a stack)
. . .
3 use of open technologies to support the integration with other
tools/frameworks or with alternative implementations of SCEL
Michele Loreti 14

SCEL component
Hardware/Virtual Machine
Networks
Input devices/Sensors
(GPS, Temperature, Battery level,CPU load. . . )
Output devices/Actuators
SCEL Processes (Threads)
Policies
Knowledge
Attr.
Ports
Michele Loreti 15

E-Vehicle Case Study in SCEL
A possible roadmap. . .
Michele Loreti 16

1 Identify basic information elements (attributes) to use for
coordinating the interactions among components;
Michele Loreti 16

2 Design component behaviours in terms of SCEL processes;
Michele Loreti 16

3 Develop a jRESP application for supporting/controlling activities of
involved agents;
Michele Loreti 16

3 Develop a jRESP application for supporting/controlling activities of
involved agents;
4 Present the obtained results in a simulation environment.
Michele Loreti 16

Ensemble-oriented programming of self-adaptive systems - Michele Loreti

Recommended

Recommended

More Related Content

Similar to Ensemble-oriented programming of self-adaptive systems - Michele Loreti

Similar to Ensemble-oriented programming of self-adaptive systems - Michele Loreti (20)

More from FET AWARE project - Self Awareness in Autonomic Systems

More from FET AWARE project - Self Awareness in Autonomic Systems (20)

Recently uploaded

Recently uploaded (20)

Ensemble-oriented programming of self-adaptive systems - Michele Loreti