C ONSISTENT M ANAGEMENT OF C ONTEXT I NFORMATION IN U BIQUITOUS S - - PowerPoint PPT Presentation

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C ONSISTENT M ANAGEMENT OF C ONTEXT I NFORMATION IN U BIQUITOUS S - - PowerPoint PPT Presentation

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C ONSISTENT M ANAGEMENT OF C ONTEXT I NFORMATION IN U BIQUITOUS S YSTEMS Gabriel Guerrero-Contreras gjguerrero@ugr.es Jos Luis Garrido jgarrido@ugr.es Carlos Rodrguez-Domnguez carlosrodriguez@ugr.es Sara Balderas-Daz

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CONSISTENT MANAGEMENT OF CONTEXT INFORMATION IN UBIQUITOUS SYSTEMS

Gabriel Guerrero-Contreras José Luis Garrido Carlos Rodríguez-Domínguez Sara Balderas-Díaz 7th International Conference on Internet and Distributed Computing Systems 22nd September 2014 gjguerrero@ugr.es jgarrido@ugr.es carlosrodriguez@ugr.es sarabd@correo.ugr.es

University of Granada Software Engineering Department

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OUTLINE

  • 1. Introduction
  • 2. Consistent Management of Context Information

> The Service Entity and Replica Manager > The Synchronization and Monitoring Services > The Context Manager

  • 3. Case Study
  • 4. Conclusions and Future Work
  • G. Guerrero-Contreras et al.

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  • 1. INTRODUCTION (1)
  • Context-aware systems use the context information to

make decisions about their future behavior

  • Ubiquitous environments make use of context-aware

techniques to provide a natural and unconscious interaction with the computational system to the user

  • Features of ubiquitous environment can affect to the

consistency of distributed context information

> Uneven conditioning, limited resources, dynamic network topology, etc.

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  • 1. INTRODUCTION (& 2)
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Support the synchronization and consistent management of distributed context information

Objective

  • SOA, EDA and middleware technologies are not enough to

support dynamic environments

  • Existing approaches to manage context information follow

a centralized scheme

  • In context-aware systems it is decisive to maintain the

correctness and the quality of context information

Motivation

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  • 2. CONSISTENT MANAGEMENT OF

CONTEXT INFORMATION

  • A model is proposed as a common basis for the

management of shared resources

> It is based on the SOA model > It provides two main services: Monitoring and Synchronization

  • A Context Manager Service has been created from

the specialization of the Synchronization service

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2.1 THE SERVICE ENTITY AND REPLICA MANAGER (1)

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2.1 THE SERVICE ENTITY AND REPLICA MANAGER (1)

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  • The applications and services are considered Software Entities

deployed in a device

  • A service may be being accessed by one or more applications,

and by one or more services (i.e., service composition)

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2.1 THE SERVICE ENTITY AND REPLICA MANAGER (1)

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  • A service can manage a kind of shared resources
  • Documents, images, database, etc.
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2.1 THE SERVICE ENTITY AND REPLICA MANAGER (1)

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  • Each service is made up of a Replica Manager
  • This avoid central controls and strengthen the system against

node disconnections and network partitions

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2.1 THE SERVICE ENTITY AND REPLICA MANAGER (& 2)

  • The Replica Manager is responsible of encapsulating

the adaptation logic regarding the deployment of the services

> Providing a distributed solution to the dynamic deployment > Improving the availability

  • f

shared resources (documents, images, etc.)

  • The Replica Manager will need the information

provided by the Context Manager Service

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2.2 THE SYNCHRONIZATION AND MONITORING SERVICES

(1)

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2.2 THE SYNCHRONIZATION AND MONITORING SERVICES

(1)

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  • The Synchronization Service is an abstract service which must

be specialized according to each particular resource to be synchronized

  • It is based on the Monitoring Service
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2.2 THE SYNCHRONIZATION AND MONITORING SERVICES

(1)

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  • The Monitoring Service is a basic service which stores all kind
  • f information about changes on the different replicas of the

shared resources

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2.2 THE SYNCHRONIZATION AND MONITORING SERVICES

(& 2)

  • Thus

a common basis for the consistent management of the shared resources is provided

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Synchronization service

The common part related to manage the resource is identified and assigned to the Synchronization service

Specialization of the service

The particular requirements

  • f a resource are implemented

in the specialization of the service

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2.3 THE CONTEXT MANAGER (1)

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2.3 THE CONTEXT MANAGER (1)

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  • The context information can be distributed

and replicated

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2.3 THE CONTEXT MANAGER (1)

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  • Through the specialization of the Synchronization service, a

Context Manager which can address these context inconsistencies at the service level is provided

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2.3 THE CONTEXT MANAGER (& 2)

  • The Context Manager will implement the ‘synchronize’ abstract method,

where it will should add the specific synchronization algorithms for managing the context data resource.

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  • 3. CASE STUDY
  • In a hospital there is an Emergency service which

form part of an ubiquitous environment

  • The Emergency service will look for the most

appropriate doctor to attend the emergency

  • Different information need to be managed

> Location of the medical staff, availability of the medical resources, profile of the patients, etc.

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  • 3. CASE STUDY
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The doctor is in the hospital Context Manager Replica 1 Context Information Emergency Service Monitoring Service

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  • 3. CASE STUDY
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Context Manager Replica 1 Context Information Emergency Service The doctor is in the hospital Context Manager Replica 2 Context Information The doctor is in the ambulance Monitoring Service

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  • 3. CASE STUDY
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Context Manager Replica 1 Context Information Emergency Service The doctor is in the hospital Context Manager Replica 2 Context Information The doctor is in the ambulance Monitoring Service

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  • 3. CASE STUDY
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Context Manager Replica 1 Context Information Emergency Service The doctor is in the hospital Context Manager Replica 2 Context Information The doctor is in the ambulance

‘synchronize’

Monitoring Service

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  • 3. CASE STUDY

/** * @param list: a list of events obtained from the `disjointSet' method */ void synchronize(List<Events> list){ foreach(Event evt in list){ evtName = evt.getMemberValue("object").GetString(); evtValue = evt.getMemberValue("value").GetString(); evtTime = evt.getMemberValue("timestamp").GetInt64(); [...] if(this.getContextObject(evtName).getTimestamp() < evtTime){ this.setContextValue(evtName, evtValue); } [...] } }

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  • 4. CONCLUSIONS
  • The devised model provides to the software engineers

the basis for a correct and consistent management of replicated/distributed resources

  • From this basis a Context Manager has been provided
  • The model is based on distributed scheme
  • It also contemplates the adaptation logic of the

replication of services at run-time

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  • 4. FUTURE WORK
  • Currently, a simulation on ns3 network simulator is

under development. In order to perform a study the behavior of the Replica Manager component

  • We plan to study the composition between the

herein presented services and other high level self- adaptive services, such as a location service

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THANKS FOR YOUR ATTENTION! QUESTIONS?

7th International Conference on Internet and Distributed Computing Systems 22nd September 2014

University of Granada Software Engineering Department