A NEED FOR AN INTEROPERABLE OPEN SOURCE

MIDDLEWARE FOR AMBIENT ASSISTED LIVING APPLICATIONS

A Position Paper

Sten Hanke, Christopher Mayer, Johannes Kropf and Andreas Hochgatterer

AIT Austrian Institute of Technology GmbH, Biomedical Systems, Viktor Kaplan Strasse 2, A-2700 Wiener Neustadt, Austria

Keywords:

Ambient assisted living, AAL, Middleware, Open source, Interoperability, Standardisation.

Abstract:

Recent European population projections underlined demographic developments towards an ”ageing society”.

A challenge of the future is ”ageing well at home” assisted by technology, while maintaining a high degree

of independence, autonomy and dignity. Ambient Assisted Living technologies try to follow this objective

by integrating intelligent assistance-systems in people’s homes. So in future there will be a high demand on

AAL applications which should fulﬁl different needs of user groups and daily living scenarios. To speed up

the development process and to make the applications more adaptive and ﬂexible to special user needs a com-

mon middleware with standardised interfaces would be desirable. This should be an open-source middleware,

which operates as an interconnection layer to the operating system and as basis for applications and services.

Furthermore the implementation of different frameworks and standards is preferable to ensure the interoper-

ability of different systems and overlapping domains in AAL. The open source approach can be essential to

initiate a community of different stakeholders and to reuse software components with a common understand-

ing on the implemented standards. The paper shows the need of such an interoperable middleware and gives

recommendations of standards and frameworks to follow. The paper explains why the open source approach

is a chance to fulﬁl the mentioned motivations. As a ﬁrst approach the EU IST FP6 project MPOWER is

introduced, which could be the basic fundament of such a middleware approach. It is an example for an open

source service oriented platform providing encapsulated AAL and health related services.

1 INTRODUCTION

Within the next decades the European society will

face serious demographic changes. Recent European

population projections for 2008-2060 published by

the European Ofﬁce for Statistics underlined demo-

graphic developments towards an ”ageing society”. It

is projected that from 2015 onwards, births will not

outnumber deaths and hence population growth due

to natural increase will cease. For this reason posi-

tive net migration will be the only population growth

factor (Giannakouris, 2008).

The old age dependency ratio, which is deﬁned as

the population aged 65 years or older related to the

population aged between 15 and 64 years, will be a

particularly dynamic indicator. It is a reasonable pro-

jection that, on average for the EU-27 and if current

trends prevail, the old age dependency ratio will ap-

proximately double during the next 50 years. This

means that in 2050 a person of working age might

have to provide for up to twice as many retired people

as is usual today (Eurostat, 2008).

The social behaviour and lifestyles as well as the

identity of the individual older person will change

if current trends continue. With higher expectancies

of life and rising retirement ages in European coun-

tries, the proportion of older people at work will in-

crease as well as the number of elderly people partic-

ipating actively in social life. Furthermore the num-

ber of elderly people living alone and of those who

live under the average subsistence level will increase

(AALIANCE, 2008). Although older people in the

future will remain self-sufﬁcient for a longer time,

more people will need high intensity care in the end-

of-life period and more people will need support in

daily life operations prior to this phase due to more

or less intense disabilities (European Commission,

2005).

517

Hanke S., Mayer C., Kropf J. and Hochgatterer A. (2010).

A NEED FOR AN INTEROPERABLE OPEN SOURCE MIDDLEWARE FOR AMBIENT ASSISTED LIVING APPLICATIONS - A Position Paper.

In Proceedings of the Third International Conference on Health Informatics, pages 517-524

DOI: 10.5220/0002767105170524

 SciTePress

2 MOTIVATION

These demographic changes will lead to different

challenges and opportunities of ageing society in

Europe such as a growing number of older people

who live by themselves and who are in need of

care and a growing number of older people lacking

basic ﬁnancial and social resources who will have

difﬁculties to obtain a minimum of health and care

services. Facing these challenges and opportunities

there exist opportunities, where technological and

socioeconomic innovation can enhance the quality

of life for older and impaired people. It is assumed

that Ambient Assisted Living (AAL) technologies

and services for elderly people can play an important

role to solve some of the increasing future problems

(AALIANCE, 2008). Information and communica-

tion technology (ICT) is believed to play a major role

in order to help older individuals to improve their

quality of life.

The following three areas of user needs are to be

addressed as stated in (European Commission, 2007):

• Ageing well at work or ”active ageing at work”:

staying active and productive for longer, with bet-

ter quality of work and work-life balance with the

help of easy-to-access ICT, innovative practices

for adaptable, ﬂexible workplaces, ICT skills and

competencies and ICT enhanced learning (resp. e-

skills and e-learning).

• Ageing well in the community: staying socially

active and creative, through ICT solutions for so-

cial networking, as well as access to public and

commercial services, thus improving quality of

life and reducing social isolation (one of the main

problems of older people in rural, scarcely pop-

ulated areas, as well as urban areas with limited

family support).

• Ageing well at home: enjoying a healthier and

higher quality of daily life for longer, assisted by

technology, while maintaining a high degree of in-

dependence, autonomy and dignity.

As can be seen there is a need for the devel-

opment of AAL technologies to support elderly

people in their daily life activities to enable them

to live an independent life in the privacy of one’s

home as long as possible. This could help to cut

the sharp increase in social costs caused by the

ongoing demographic change. Ambient Assisted

Living (AAL) technologies try to follow this ob-

jective by integrating intelligent assistance-systems

in people’s homes. Modern sensor-techniques and

IT-based evaluation of data, i.e. behaviour pattern

recognition algorithms, should support the safety of

the inhabitants. In other words, current sensor events

are compared to predeﬁned or learned patterns and

if the situation differs from normality alarms are

triggered by the AAL-system at different levels (i.e.

as a feedback to the care receiver, as an information

for relatives or as an alarm to a nurse and/or a doctor).

AAL applications respectively technologies

should be based on a middleware, which is open

to the public and works as an intermediate layer

between the operating system and the application

itself. The middleware has to be adaptable in terms

of services that can be implemented. Furthermore it

should be ﬂexible and freely conﬁgurable to satisfy

user needs regarding the development of applications

and user interfaces. Moreover it would be a good

starting point for rapid development of applications

and services. As a consequence the development

process would be more cost- and time-efﬁcient. A

realisation as an open source project would help to

spread it in a big community and a beneﬁt would be

more reliability and security in further development

stages.

To ensure an interoperability and interaction of

different AAL applications and systems standards

should be the basis of all technologies. Furthermore

the idea of open source software can enhance the

coalescence of different approaches. Following

ideas about standarization principles, open source

approaches and generalization of interfaces and their

interoperability are presented.

3 ONE MIDDLEWARE FOR

APPLICATION DEVELOPER

There are a number of architectural characteristics

that can be used as basis for reasoning about what

might be considered appropriate quality attributes that

can be measured. These include interfaces and lay-

ers, standards and data interoperability. Middleware

provides an example of the layering principle. It sep-

arates the applications from the operating systems on

which the applications run. As outlined in ﬁgure 1,

middleware services are sets of distributed software

that exist between the application and the operating

system and network services on a system node in the

network (Kasunic and Anderson, 2004).

An essential aspect of architecture is the establish-

ment of technical standards. In general, standards de-

ﬁne common elements, such as user interfaces, sys-

tem interfaces, representations of data, protocols for

the exchange of data, and interfaces accessing data

HEALTHINF 2010 - International Conference on Health Informatics

518

Figure 1: Middleware.

or system functions. Technical standards provide a

number of advantages for the systems architect. With

regard to interoperability, standards are important be-

cause they are accepted by multiple vendors, thereby

increasing the likelihood that a collection of systems

from diverse sources will be able to interoperate. It

has become generally accepted by now that although

standards are certainly beneﬁcial, simple adherence

to standards is not sufﬁcient to guarantee interoper-

ability. Even when there are accepted standards and

compliant products, interoperability is facilitated but

not assured as there are options within standards and

different releases and versions of products.

4 INTEROPERABILITY IN AAL

APPLICATIONS

Interoperability is the ability of different information

technology systems and software applications to com-

municate, to exchange data accurately, effectively and

consistently, and to use the information that has been

exchanged. Important for interoperability is not only

the syntactical interoperability of simply connecting

devices and modules through sharing and exchang-

ing. Speciﬁed data formats, communication protocols

and the like are therefore fundamental. But also the

semantic interoperability and therefore the ability to

use and understand the exchanged information is im-

portant. Beyond the ability of two or more computer

systems to exchange information, semantic interoper-

ability is the ability to automatically interpret the in-

formation exchanged meaningfully and accurately in

order to produce useful results as deﬁned by the end

users of both systems. To achieve semantic interoper-

ability, both sides must defer to a common informa-

tion exchange reference model.

Services for the ageing and cognitively disabled

do not and will not exist in isolation. The AAL do-

main consists of a large set of independently devel-

oped systems and services in existing environments.

On top of the value of these individual systems addi-

tional value could be created by exchanging data be-

tween these systems or even aggregate the data in a

system for analysis and to give proper feedback or

alerts to relevant systems or users. These systems

and services should be able to communicate with each

other not only by exchanging data but also under-

standing each other’s data. This can only be achieved

by agreeing on a lot of issues in other words by using

standards (AALIANCE, 2009).

The ageing society’s conditions require that we re-

think traditional models of care. One prominent as-

pect of new care models for this target group is the co-

operation of different stakeholders in the care process.

Stakeholders include the patient himself, his relatives

and caregivers such as the general practitioner, hospi-

tal personnel, homecare personnel and insurance and

social security departments as well. Healthcare sys-

tems are expected to maintain the continuity of care,

shared care and the empowerment of patients in the

management process. Many relevant systems and ap-

plications exist, that AAL services might need to in-

teroperate with. Healthcare applications built around

Europe use proprietary data formats and some sys-

tems are designed to interoperate with others based

on standardized data formats, such as HL7 and CEN

standards. Consequently an interoperability solution

needs to be able to communicate with external parties

in an agreed upon format, even though the internal

system is based on proprietary formats.

So far we have experienced in many projects in the

AAL domain that within one after the other project

different proprietary solutions are developed. A lot

of funded projects are like reinventing the wheel and

so far no common sense on even some universal used

modules or components with open and described in-

terfaces can be found. Many working and already

implemented solutions in residential house or smart

home applications are generally proprietary solutions

in the case of sensor networks, middleware imple-

mentations and even data formats and records. Of

course interoperability and standardisation is already

mentioned in every project proposal but a real guide-

line or state of the art for practical use is still missing.

It seems like there is nowadays a situation in the AAL

domain like in the eHealth domain years ago. Impor-

tant will be to learn from this domain and to speed

up the process of using interoperable and standard-

ized systems and frameworks. Of course AAL is an

A NEED FOR AN INTEROPERABLE OPEN SOURCE MIDDLEWARE FOR AMBIENT ASSISTED LIVING

APPLICATIONS - A Position Paper

519

application domain with a lot of overlapping subdo-

mains where so far there has not been a real need for

interoperability. In the AAL domain there must be a

interchanging of the e.g. eHealth domain, the home

entertainment domain, the home automation domain,

the household appliance domain and many more. The

status quo in the AAL operation are conﬂicting ver-

sions of standards as well as conﬂicting implementa-

tions thereof. This is also caused by the fact that so

far the existing standards, like the ISO/IEEE 11073

standards for domotic sensors, have not been used and

implemented in many applications and cases. Thus

there is no experience of e.g. missing parts or any

other lessons learned from usage. There are not many

examples to show how to implement these standards

in practice. Of course there is also a lack of standards

in some ﬁelds of AAL applications like for remote

maintenance, terminology and ontology, emergency

and alarming calls and procedures and in some extend

middleware etc. And there is a lack of certiﬁcation

and also labelling processes of devices and modules

in the AAL domain.

4.1 Using Standards and Frameworks

The structure shown in ﬁgure 2 presents four cate-

gories of standards relevant for AAL (AALIANCE,

2009). Starting from the bottom:

• Equipment and environmental standards (EES):

these are standards agreed on in a large domain

and sometimes imposed by regulation. Quite of-

ten they have to be followed if one wants to en-

ter the market and processes to change them are

very difﬁcult. These standards are usually not ICT

related but relate to environmental (e.g. EMC),

quality (ISO 9001), safety, physical product prop-

erties (e.g. CE norms), manufacturing and instal-

lation processes. AAL products however have to

comply with these standards but they will hardly

be inﬂuenced by the AAL community. Some

speciﬁc standards exist e.g. EN 50134 for so-

cial alarm systems, CENELEC Smart House and

CENELEC TC 205 (HBES) for home and build-

ing electronic systems. A number of standards in

this area will be mentioned but not explored in

greater detail.

• Generic technology standards (GTS): these stan-

dards have often been developed by standard

development organisations or industrial associa-

tions, which are either very broad associations like

IEEE or more closed ones like W3C or UPnP,

Bluetooth, or USB. Often multiple alternatives for

certain technologies exist like Bluetooth, Zigbee,

Z-wave for personal area or local area networks.

For AAL one or sometimes more than one should

be selected. If more than one is selected it might

be necessary that an aggregating device supports

more than one option at the same time. The inﬂu-

ence of the AAL community on these standards

might be in communicating speciﬁc needs from

the AAL domain either on the standard itself or

on proﬁles on top of these standards.

• Domain speciﬁc standards (DSS): these are stan-

dards for sub domains that are important for an

integrated AAL solution. Examples of relevant

sub domains are healthcare (with sub groups like:

tele-monitoring, medication registries, electronic

health records, personal health records), home

control, home safety, home security, remote pay-

ment systems, etc. Sometimes generic technolo-

gies have specialisations for certain domains like

the Bluetooth medical proﬁle and the USB device

class deﬁnition for personal healthcare devices. In

this category the AAL community might give in-

put to the standard development organisation for

extensions.

• Speciﬁc AAL standards (SAS): these are stan-

dards speciﬁc to the AAL domain. There are very

limited potential candidates available at the mo-

ment: data exchange standards and ontologies to

enable the exchange and understanding of data be-

tween different subsystems for reasoning on this

data and interacting with the users. Some of these

standards might exist or are evolving in speciﬁc

domains as e.g. healthcare.

AALintegration like:

ange

ormats

Ontology‘s

Domainspecific like:

Healthcare:teleͲmonitoring,medication management,care organisation

Homecontrol

safet

and securit

Infotainmentand social connectedness

Electronicshopping,orderning and payment

Generic technologies like:

Connectivity:PAN,LAN,WAN

Webbased services

Distributedsystems,middleware

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Homeand building electronics

Safety,EMC,Connectors,material

Figure 2: Standards relevant for AAL (AALIANCE, 2009).

Although the ”Integrating the Health Care Enter-

prise” (IHE) (IHE - Integrating the Health Care En-

terprise, 2008) started to implement the framework

for health applications, the communication structure

could be used as well for homecare applications for

elderly and persons with dementia. This could be

easily done because there are already structures for

HEALTHINF 2010 - International Conference on Health Informatics

520

point-of-care devices. The beneﬁt would be the ac-

cordance to established standards and standard frame-

works. It is obvious that there is a beneﬁt because

of already established point-of-care communications

from the medical ﬁeld (blood pressure, temperature

etc.), which can be adapted. Of course the whole IT

structure and the cross-enterprise-document sharing

(XDS) deﬁned in the IHE framework could handle

personal health data and information, which could be,

depending on the use cases, even important for medi-

cal help.

The ISO 11073 offers plug-and-play and a func-

tional as well as a semantic interoperability between

sensor systems and aggregation systems. In this stan-

dard all functions and use cases, which are deﬁned

for patient oriented health care and of course in some

aspects for smart home for elderly, are already ob-

ject orientated modelled. That means a so called

domain information model is constructed where the

device, the functionality, the measured data, set-

tings, alarm functions, patient information and in-

terfaces are deﬁned. Furthermore there are codes

for all information elements deﬁned as ”nomencla-

ture” (ISO/IEEE 11073-10101) and ”data dictionary”

(ISO/IEEE 11073-10201). The communication stan-

dard POCT-1A is implemented in the ISO 11073.9

and is specialised for patient near point of care. In

principle the functionality of POCT1-A could be re-

alised by HL7, but the functional range of the HL7

structure is in some cases (single sensors) too high

dimensioned. So it depends on the special functions

to realize what should be realised on the sensor (ac-

cording sensor often have a restricted hardware) and

the local controller. Because of a clear deﬁned mes-

sage communication the unique interpretation of the

standard is guaranteed. POCT1-A is a ﬂaring of HL7

not a competition standard. The advantage of the

CEN/ISO/IEEE 11073 is that it is the only compre-

hensive system of point-of-care medical device com-

munication standards. The modality categories range

from real-time operating medical equipment to point-

of-care test devices. Wired as well as wireless IR and

RF network technologies are supported. If healthcare

providers and management organizations want point-

of-care to record transparency of information, they

must demand medical device interoperability. In ad-

dition the activity is regularly coordinated with other

health information activities (HL7, NCCLS, IHE and

DICOM) by the core development bodies.

The Continua Health Alliance can help to over-

come the barriers of using standards. The Continua

Health Alliance is a non-proﬁt, open industry coali-

tion of healthcare and technology companies join-

ing together in collaboration to improve the quality

of personal healthcare. With more than 200 compa-

nies around the world, Continua is dedicated to es-

tablish a system of interoperable personal health so-

lutions with the knowledge that extending those so-

lutions into the home fosters independence, empow-

ers individuals and provides the opportunity to truly

personalized health and wellness management (Con-

tinua Health Alliance, 2009). It is important to know

that Continua is not developing standards but is rec-

ommending standards like the ISO/IEEE 11073 and is

also providing a certiﬁcation process to make the ben-

eﬁt of devices visible to the user. The beneﬁt for AAL

applications is that Continua has beside the scope on

managing chronic diseases and ﬁtness a scope on ag-

ing independently what could be used as a standard-

isation process for devices and applications in the

AAL domain. Therefore more and more companies

and technology providers but also research institu-

tions from the AAL domain are joining the Alliance.

The implementation of standards and interoper-

ability by using frameworks is not only a major is-

sue concerning the usage of the open source ser-

vices, it is also a major issue on private data pro-

tection. Recommendable are the frameworks pro-

vided by IHE (Integrating the Healthcare Enterprise)

and HIMSS (Healthcare Information and Manage-

ment System Society). As an example IHE provides

a Basic Patient Privacy Consents (BPPC) mechanism

to record the patient privacy consent(s), a method to

mark documents published by XDS with the patient

privacy consent that was used to authorize the pub-

lication and a method for XDS consumers to use to

enforce the privacy consent appropriate to the use.

The leadership of HIMSS, Health Level Seven (HL7),

Integrating the Healthcare Enterprise (IHE) and the

HIMSS EHR Vendors Association (EHRVA) have be-

gun to work on this effort by establishing a coordi-

nated set of activities that would provide an HL7 im-

plementation guide and launch this new IHE domain

called Patient Care Coordination with demonstrated

interoperability of medical summary documents by

January 2006.

4.2 The MPOWER Project

MPOWER has been an EU IST FP6 project (ﬁn-

ished June 2009) with the objective to create a mid-

dleware platform that enables rapid development of

novel smart house systems and applications. This

platform should simplify and speed up the task of de-

veloping and deploying services for persons with cog-

nitive disabilities and elderly. The approach has been

to encapsulate the functionality by a service oriented

architecture (SOA) and by using the model driven ar-

A NEED FOR AN INTEROPERABLE OPEN SOURCE MIDDLEWARE FOR AMBIENT ASSISTED LIVING

APPLICATIONS - A Position Paper

521

chitecture approach (MDA). To enable adaptivity and

the possibility to integrate the middleware with ex-

ternal systems a requirement has been the implemen-

tation of existing standards and frameworks (HL7,

ISO, CEN, IHE etc.). For demonstration purposes the

implemented services are containing communication

services, information services, management services,

sensor services as well as security services.

As already mentioned MPOWER is based on SOA

by using the web services WSDL and SOAP. Thus it

is an interoperability enabler, as the web service front

ends allows heterogeneous platforms to interoperate

(e.g. .NET and Java). This is not enough as the mes-

sages, which can be exchanged by applications and

systems, can be very different and there can be appli-

cation policies (such as security) which need special

interoperability requirements. To this end, we have

designed a reusable interoperability architecture that

encapsulates the interoperability components in such

a way that changes in these components or the exter-

nal systems they relate to are hidden from the rest of

the MPOWER framework. For other MPOWER ser-

vices the interoperability services look just like any

other MPOWER service. The mechanism is to use

a design pattern known as the message translation.

We are not the ﬁrst ones facing interoperability chal-

lenges. It is a reoccurring problem and therefore pat-

terns exist that explain how one should design middle-

ware components in order to achieve interoperability.

We provide this pattern with its subpatterns and ex-

plain their relevance to MPOWER.

To see this middlware, which is implemented,

used, maintained and expanded by different stake-

holders, the MPOWER consortium provides all im-

plemented services as open source (MIT license) un-

der the Free-mpower project. It is hosted on Source-

Forge under http://sourceforge.net/projects/free-

mpower/. Everyone is able and also invited to browse

and acquire the source code, basic documentation

to several services and the toolchain as well as the

service deployment process, the handbooks as well

as the open source toolchain itself and to submit re-

quests. Members of the sourceforge project can also

post code, make documentation and post pictures of

e.g. running application GUIs. Provided services are

for example security services, database management

service (with init data), patient manager service,

calendar service with reminder (HL7v3), patient

information message board service, localisation

service, frame sensor service (ISO/IEEE 11073) as

well as alarming and notiﬁcation services and many

others. Of course documentation is provided for

these services and the overall architecture.

As short term projects the usage of the free-

mpower setup is thinkable for any student project,

any proof of concept application or rapid prototyp-

ing. As long term projects the free-mpower project

could be the basis for following European projects

any commercial solutions or any application provider.

For community building purpose, which is obviously

a very important point for an open source project,

a growing framework by using and adding service

would be desirable.

MPOWER is an open source service oriented plat-

form providing encapsulated AAL and health related

services. It includes standardised smart house sensor

interfaces (ISO/IEEE 11073), interoperable interfac-

ing for legacy systems (CDA, HL7-HSSP) and exter-

nal service connection (mobile alarming / reminding

/ communication), security services, social and infor-

mation services (HL7). All results are shown in ﬁgure

Figure 3: Results from the MPOWER project.

5 THE CHANCE OF OPEN

SOURCE

To provide the services of a middleware and also soft-

ware application modules as open source to the com-

munity, is a big advantage for projects and a subse-

quent use of the project results as well as it may en-

sure the usage of the platform and the consistency of

the developments beyond the project runtime. On the

other side it is important to be aware of the challenges

and requirements of open source for the project and

application developers.

At ﬁrst the MIT License states explicitly the rights

given to the end-user, including the right to use, copy,

modify, merge, publish, distribute, sublicense, and/or

sell the software. In detail the end-user are on the one

hand the application developer, which may want to

build applications based on the services, and on the

other hand the care receiver who wants to use the ser-

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522

vice including the application. In comparison to the

GPL license the application developer is allowed to

redistribute the modiﬁed software and an application

which is an incentive for the professional application

developer and can expand the usage of the services

itself.

Another big advantage of open source services in

the AAL context, which should be taken into account

when talking about ethical issues, is the advantage

of the transparency of the services and the code it-

self. Transparency is inherent to every release of open

source code. The customers can see it and thus the

vendor has no secrets.

But transparency also applies to vendor’s opera-

tions. Vendors who are opaque on their strategy gain

fewer beneﬁts from a open source release of code.

The most successful open source vendors are trans-

parent on their strategies and the most successful open

source customers are transparent in turn, being frank

about their needs. Transparency, the need for it, the

desire for it, extends outward from there. The advan-

tage of the usage of open source in eHealth and AAL

projects concerning the support of standards has been

pointed out as a need by the member states of the Eu-

ropean Union. There is a need to support actions that

cover the development of standards addressing the in-

teroperability of diverse systems and services and to

explore in particular the possibilities of open source

applications to achieve this objective. In this context,

the need for future standards is clearly emphasized

to solve interoperability concerns in a way that all

stakeholders will beneﬁt from the possible adoption

of Open Source reference implementations for care

services. In addition, an open and more free access

to future and existing e-Health and general interop-

erability standards in the AAL and eHealth service

providing should be recommended, taking inspiration

from models such as the World Wide Web Consor-

tium. The exchange of experience in the use of open

standards and open source solutions among health ad-

ministrations in Member States should be promoted

(European Commission, 2004). Success in develop-

ing a European e-Health Area and AAL standard con-

form platform will draw on sharing best practices and

experience across the Union, as systems are deployed

and organizations redesigned. Open source applica-

tions play an important role in achieving interoper-

ability (European Commission, 2004).

Maybe the biggest ethical issue when providing

open source services in the AAL context is the issue

of data privacy and data protection. This is very im-

portant because the services generally developed in

AAL related middleware and application projects use

medical and social relevant data which underlie spe-

cial data privacy regulations.

The advantage of transparency of open source

code and the possibility that any expert has the pos-

sibility to ﬁnd security leaks and general mistakes in

the code and can ﬁx them, leads also to a high de-

mand on secure software development and the inte-

gration of security services so that the transparency

can not be misused. As a result of the transparency

the application developer can ﬁx and provide special

data security, e.g. in the case of medical data treat-

ment, and provide it as a business to user organization

or private users.

The transparency of open source also gives the

possibility to expand the functionality of the service

or the application, which can be part of a business

strategy, and to learn from the structure and interfaces

of already implemented services.

A very important point concerning the usage of

open source software components is the community,

which uses and kind of maintains the project or at

least can give assistance or support.

A main goal of AAL related projects develop-

ing open source middleware software components

is to build a powerful community of application

developers and users of the open source services

and application. This can be any kind of possible

stakeholders e.g. universities, national organizations,

residential house operator etc. This will be important

to guarantee maintenance of the services to provide

good quality to the user and as well to set up and

include perfect security mechanisms and to close

possible security leaks. The attraction for developers

to provide software components under the MIT

license as open source may be that open source

services under the MIT license are underlying the

international valid copyright law. That means the

provider of the services still holds the international

In the social thinking of the gift economy, where

valuable goods or software modules are given with-

out any explicit agreement for immediate or future

reward, the fact of providing a middleware for AAL

applications makes sense to fulﬁl the aim of having a

commonly used system. The gift economy is a more

and more desirable thinking in western companies or

by private persons, who are not essentially depending

on a money exchange. Ideally, simultaneous or recur-

ring giving serves to circulate and redistribute valu-

ables within the community. Jordan Hubbard wrote

in his article ”Open Source to the Core” (although

referring to it as a barter economy) and essentially

describes a gift culture, where reciprocity is a broad

community custom, rather than an explicit quid pro

A NEED FOR AN INTEROPERABLE OPEN SOURCE MIDDLEWARE FOR AMBIENT ASSISTED LIVING

APPLICATIONS - A Position Paper

523

quo (Hubbard, 2004): ”The volunteer software engi-

neers in the open source software community are far

more likely to help those who have demonstrated their

commitment to the success of the overall open source

software development process.”

6 CONCLUSIONS

There have been many research projects concerning

a common middleware for AAL applications. There

is a high demand on technical standards in the AAL

domain but their is also a high activity deﬁning stan-

dards going on. For future developments it will be

important to reuse existing developments and to en-

hance or adapt them. In the future it will be important

to have more and more applications with standardised

interfaces and protocols implemented. These experi-

ences can be used by standard organisations to adapt

the documents to users’ and developers’ needs. We

think that the open source approach can help a lot to

spread a common sense a software and standard im-

plementations.

The AAL domain should take the chance of

reusing frameworks and standards from the medical

domain because there is an overlap of this two do-

mains. But more important is the fact that it should

be avoided to make the same experience again and

have an unsatisfying solution for the next years. Even

in the medical domain their is still much to do when

thinking of implemented standards of medical device

communication or data exchange between different

legacy systems. The AAL domain should use the al-

ready existing knowledge and base ﬁndings on it.

This will be very important because in the AAL do-

main their are also a lot of other ﬁelds where standards

are missing and where the community should work on

like standards for basic user needs evaluation, basic

aspects of layout and designed user interfaces, basic

standards for the demand on usability, standards on

privacy data also for social data and basic standards

for evaluation methodology.

The MPOWER project could be a basis for creat-

ing a community and to start a common implemen-

tation of an AAL middleware. The beneﬁt is that it

is easy adaptable and even some few services can be

used as a standard and maybe integrated in other run-

ning AAL applications, because of its service encap-

sulation.

For the AAL community as a whole it will be a

task to (AALIANCE, 2009):

• Increase the awareness on existing standards

• Demonstrate the advantage of collaborative and

integrated applications and services based on us-

ing standards

• Develop and promote a reference model that gives

guidance to product and service developers.

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