A Policy-Based Framework for e-Health Application

1
A Policy-Based Framework for e-Health
Application

• Giovanni RusselloChangyu DongNaranker
  DulayImperial College London

Jatinder Singh Jean Bacon Ken Moody University of
Cambridge
2
Caregrid Project

• Main project goal
• Enhancements for development and deployment of
  healthcare applications
• Key features trust, security, privacy and
  context models
• Results working towards the realisation of a
  middleware

3
Challenges

• Scalability healthcare applications range from
  small-scale body sensor networks up to
  large-scale distributed systems
• Flexibility dynamic environments and
  unpredictable scenarios
• Manageability users and resources change
  unpredictably over time

4
Assisted living

• Treating and monitoring patients at home (or in
  sheltered houses)
• Carers visit the patients and provide the
  necessary medical care to their case
• Installing hardware and software for
• Monitoring (body sensors, infrared cameras, etc.)
• Assisting patients and cares
• Providing appropriate security and privacy

5
Framework Components

• Ponder2 for management of Entities and Resources
• Domain organisation
• Authorisation and Obligation policies
• Communication by means of Event-based middleware
• Distribution of events for interaction
• Prioritising events

6
Entity and Resource Organisation

• Ponder2 allows the specification of hierarchical
  domain structures that contains Managed Objects
• An Entity (such as a doctor) is defined by means
  of a Managed Object Template (MOT)
• Managed Object Instance (MOI) is used to
  represent a specific instance of an Entity
• Resources are represented by means of simple
  Managed Objects.

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An MOT Example
lt Root Domain
lt Sub-domain for carers
lt Sub-domain for Doctors
lt MOT specification for Doctors
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MOI Instantiation
Entity E Presenting Credentials
Finding the matching MOT
Instantiating an MOI for a doctor
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Authorisation Policies

• Define the set of access rights that a subject
  has on a target
• auth/- subject, action, target
• when condition

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Obligation Policies

• Event-Condition-Action for dynamically adapting
  the system to changes
• on Event
• when Condition
• do Action

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Obligation Policies

• Capture obligations entities must fulfil
• oblig MedicineIntakePolicy
• after 3h 50min from MedSwallowedEvt -gt AlertEvt
• unless MedSwallowedEvt
• after 4h 10min from MedSwallowedEvt -gt AlarmEvt
• unless MedSwallowedEvt
• on MedSwallowedEvt do log("medicine taken",
  time)
• on AlertEvent do alertPatient("Medicine in 10
  min")
• on AlarmEvent
• do sendAlarmToGP("No medicine taken")

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Practical Case Edema Case Study

• Edema refers to swelling caused by excess fluid
  retention
• Carers regularly visit patients at home and
  perform
• Monitoring by measurements
• Providing appropriate medications

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Case Study in Details

• Deployment in the home environment
• Carers visiting the patients home
• Authentication when access home
• Guiding the carers in their tasks
• Leaving the patients home

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Deployment

• Carers could use PDA carrying the necessary data
  and software
• In the sheltered house
• Sensors for monitoring the patients
• PC and set-up boxes for storing data
• TV and phones for communication

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Domain Structures for the Edema Case Study
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Controlling the Access to Resources
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Fulfilment of Obligations

• oblig BMPolicy
• after 30min from NurseInEvt -gt AlertBMEvt unless
  BMTakenEvt
• after 10min from NurseOutEvt -gt Alert2BMEvt
• unless NurseInEvt or BMTakenEvt
• after 30min from NurseOutEvt -gt HNotifyBMEvt
• unless EmergEvt or BMTakenEvt
• on BMTakenEvt do log("MB taken", time)
• on AlertBMEvt do alertNurse("BM within 30 min")
• on Alert2BMEvt do alertNurse("Departed without
  BM")
• on HNotifyBMEvt do sendNotToHosp("No BMtaken")

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Leaving the Home Domain

• When the carer completes the tasks and leaves
  allocated resources must be relinquished.
• Obligation policies can be defined to respond to
  such an event.
• oblig NurseLeavePolicy
• on NurseOutEvt
• do nurseMOI.disablePolicies
• home.remove(nurseMOI)

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Other Services

• A Trust Framework for handling autonomously
  decisions when unknown entities are involved
• A monitoring and auditing service for
  responsiveness, reliability, and performance

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Conclusion and Future Work

• Policy-based framework that provides the
  appropriate abstraction for dynamic environment.
• Policies can be used for managing access rights,
  dynamically adapt the system and assist entities
  in their duties.
• For the future, we envisage the use of workflow
  systems for handling more complex situations.
  Moreover, we are working on extending our policy
  language for capturing the notion of trust.