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Portable personal RFID databases for AAL-enabled healthcare

environments.Ignacio Díaz-de-Sarralde, Diego López-de-

Ipiña, Xabier Laiseca, Sergio BlancoDeustoTech – Deusto Institute of Technology

Avda. Universidades 24, 48007, Bilbao, SPAIN{isarralde,dipina,xabier.laiseca,sergio.blanco}@deusto.es

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Contents• Introduction• Objectives• Related Work• An NFC-supported platform: • RFID tags as portable databases• Relaying care data in the real-time web world• Conclusion• Further questions

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Introduction• Technology:

– RFID is mainly used as a low-cost solution to uniquely identify objects.• RFID tags encode a URI from where an object’s data can be accessed and operated

(Data-on-network approach)• However, passive HF RFID tags allow significant data storage (up to 4K), enabling

immediate access to the desired object’s metadata.

• Domain:– AAL aims to increase our quality of life and autonomy and to reduce

the need for being institutionalised or aiding it when it happens– Healthcare and Elderly care centres are challenging environments

from the data gathering and publishing perspective.

• Solution: – A hybrid approach where a data on tag approach is used in order to

gather lifelogs of residents, occasionally contacting a back-end in order to synchronize or enrich said stored data.

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Objectives

• This work has a two-fold objective:1. Experimental: Evaluate how much data can

actually be stored in HF RFID tags2. Practical: Combine the RFID data-on-tag

approach with NFC to improve data management in a healthcare centre, where:• RFID tags can serve as temporary repositories of care

events• Interactions between residents’ RFID wristbands and

staff’s NFC mobiles can improve care data management and keep relatives up-to-date

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Related Work

• NFC technology operating on 13.56MHz combines the functionality of a RFID reader device and a RFID transponder into one integrated circuit– NFC read/write mode allows NFC devices to access data from

an object with an embedded RFID tag

• The combination of NFC technology and RFID tags has been used in the last few years in several research projects related to medicine and caretaking – However, so far RFID applications have not incorporated

custom data directly onto RFID tags

• Still prevails a generic lack of standardization, only alleviated by initiatives such as the Continua Health Alliance

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A Platform to Enhance Care Data Management

• Caretaking is a suitable domain for combining NFC technology and the RFID data-on-tag approach in order to enhance the data gathering process– The ill and elderly people are looked after at different

domains (patient’s homes or their families’, residences, hospitals) and by different people (relatives or staff), making very difficult to reconcile the information gathered

• Some issues:– Residents do not always stay and sleep at the same

place– Data capture is not highly prioritised– IT support at care centres and family homes is diverse

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Features

• Supports caretaker on structured patient data recollection and storage

• Allows collected data to be used efficiently– By enabling easy and clean data writing and

reading of RFID tags with NFC phones– By relying patient activity to relatives via external

services

• Research novel RFID applications in daily use– Uses HF RFID tags as embeddable and portable DBs– Proposes optimal data encoding and compression

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RFID Tags as Portable Databases

• The NFC Forum specifies a data-packaging format called NDEF (NFC Data Exchange Format) to exchange information between an NFC device and another NFC device or an NFC tag

• Evaluation of HF RFID tags as tools to store data:1. Select a set of easily wearable

tags (ISO 15693-compatible) with as much storage capacity as possible and still compatible with NFC

2. Identify the maximum number of useful bytes storable in the selected tags

3. Develop a new efficient mechanism to store data on HF RFID tags

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Storage Capabilities of a 4K Mifare Watch

Mifare 4K Watch

Record Size (bytes)Number of stored

recordsAverage writing

time (ms)

Actual bytes written (record ID of

4 bytes)1 372 8081 1860

2 335 7724 2010

4 279 7259 2232

8 209 6846 2508

16 139 6520 2780

32 83 6283 2988

64 46 6252 3128

128 24 6093 3168

3196 1 6214 3200

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Efficient Recording of Data in HF RFID Tags

• Evaluating storage capabilities, it was decided that only one record NDEF messages should be used– No standard on the data structures

used by care centres to keep data on their interns was found

– Therefore, we have developed our data structures and encoding mechanisms:

• Patient metadata is enriched with lifelog message entries detailing concrete events in said patient’s medical history.

• Range Encoding Compression is applied to said data structure.

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• ElderCare proposes a special purpose compressed serialization method in order to maximize the usage of HF RFID tags’ storage:– Raw data (Stringified) – human readable string representation of a

lifelog. – Encoded – transformation of a stringified care log into a more optimal

representation. – Serialized data– it is a byte representation of a care log– Compressed data – applies a Range Encoding compression algorithm

to the byte representation.

ElderCare Care Log Encoding

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ElderCare Log Encoding

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An NFC-supported Platform

Features: Allows for anywhere at any time, asynchronous

multi-user gathering of data Allows for asynchronous care data reporting to

both internal and external services Integrated components

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ElderCare Mobile Client

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Relaying care data in the real-time web world.

• The ElderCare AAL platform does not only keep custom data to enhance the daily activities in a care centre but ...– It also allows exporting part

of that data to external services (such as Twitter, e-mail, SMS, RSS feeds...)

• Relatives and friends can follow the lifelog of residents.

• Digital copies of a patient’s medical history and reports can be sent by e-mail.

• ...

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Conclusion• ElderCare stores a log for every new care procedure applied on the

resident’s RFID wristband, following a data-on-tag approach– It uses RFID tags as mini databases

• ElderCare makes data stay at any time with the resident and be available in real-time and without relying on wireless links – Our experiments show that the storage capacity of 1K (wristband) or 4K

(watch) Mifare RFID tags, aided by CareTwitter’s custom-built data serialization format, is sufficient for storing the care logs of a whole day

• The integration of ElderCare with external services (such as Twitter) proves the high potential of using interactions with everyday objects or people to automatically publish data into Internet– The lifelog of a resident is available to authorized users– Detailed reports can be automatically sent without additional efforts

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