UBIQUITOUS SOFTWARE DEVELOPMENT DRIVEN BY

AGENTS’ INTENTIONALITY

Milene Serrano, Maurício Serrano and Carlos José Pereira de Lucena

Department of Informatics, Pontifical Catholic University of Rio de Janeiro (PUC-Rio)

Rua Marques de São Vicente 225, 13º andar, Ed. Padre Leonel Franca, Gávea, Rio de Janeiro, Brazil

Keywords: Ubiquitous Software Development, Agents’ Intentionality, Collaborative Multi-Agent Systems, Distributed

Intentionality Modeling, Belief Desire Intention Model.

Abstract: Ubiquitous computing is a novel computational paradigm in which the users’ mobility, the devices’

heterogeneity and the service omnipresence need is intrinsic and intense. In this context, the ubiquitous

software development poses some particular challenges that are not yet dealt with by the traditional

approaches found in the Software Engineering community. In order to improve the ubiquitous software

development, this paper describes a detailed technological set based on multi-agent systems (MAS), goal-

orientation, the BDI (Belief Desire Intention) model and various frameworks and conceptual models.

1 INTRODUCTION

Nowadays, the advances of the Internet, the wireless

network, anywhere and anytime information

dissemination and device heterogeneity are

contributing to the unfolding and growth of studies

in Ubiquitous Computing. This novel paradigm

represents an expansion challenge for Software

Engineering professionals.

Ubiquitous Computing, introduced by Mark

Weiser and published in 1991, idealizes a world in

which the main requirements are the users’

satisfaction, the service omnipresence and the

process complexity invisibility to provide different

services. In this distributed and untapped context, it

is important to investigate traditional and emergent

technologies that improve the ubiquitous software

development. Some particular challenges of

ubiquitous applications are: the inherent users’

mobility; the need to consider different devices and

the integration of a number of environments.

Ubiquitous software development poses some

particular challenges, such as those presented

previously, which are not yet dealt with by the

traditional approaches found in the Software

Engineering community. In order to improve the

ubiquitous software development, this paper

describes a detailed technological set based on

collaborative MAS, goal-orientation, the BDI model

and various frameworks and conceptual models. Our

main contribution is to purpose a systematic way to

develop ubiquitous software centered on intentional

frameworks and conceptual models reuse.

Additionally, as we are considering the

Ubiquitous Computing and the MAS paradigms, it

increases the importance of investigating some

special concerns. For example, the agents in

ubiquitous applications must be based on context to

adapt their actions according to real world situations.

The BDI model (Pokahr et al. 2005) can be viewed

as an emergent model to develop software agents

based on their intentionality. The intentional agents

reason, learn and take decisions according to their

beliefs, desires and intentions. The beliefs can be

stored in the agent’s knowledge base, and represent

what the intentional agent believes that the real

world is. The desires are the goals to be achieved.

The intentions are the strategic plans to achieve the

goals. The BDI model can be improved by using

fuzzy logic, as shown in this paper, which

significantly increases agents’ cognition. Thus, a

new approach for the agent-oriented ubiquitous

software engineering has to be considered.

This paper is organized in sections. Section 2

shows the related work. Section 3 describes some

ubiquitous challenges. Section 4 presents our

proposal. Finally, Section 5 summarizes the

conclusions.

Serrano M., Serrano M. and Pereira de Lucena C. (2009).

UBIQUITOUS SOFTWARE DEVELOPMENT DRIVEN BY AGENTS’ INTENTIONALITY.

In Proceedings of the 11th International Conference on Enterprise Information Systems - Software Agents and Internet Computing, pages 25-34

DOI: 10.5220/0001857400250034

 SciTePress

2 RELATED WORK

According to (Saha et al. 2003), Ubiquitous

Computing is an interesting domain that is

investigated by various research groups: (i) Aura

(Carnegie Mellon University): the main objective is

providing easy access to different services anywhere

and anytime; (ii) Endeavour (University of

California in Berkeley): the main objective is

allowing the user interaction with different devices,

people, and information; (iii) Oxygen (MIT)

: the

main objective is naturally incorporating the

communication technologies in the people life; (iv)

Potolano (University of Washington)

: the main

objective is creating a testing environment for the

investigation of Ubiquitous Computing challenges

using specific devices for each task.

Additionally, there are several research projects

that consider different concerns of Ubiquitous

Computing, such as the content adaptation and the

context awareness. In (Ravindran et al. 2002), the

authors emphasize the importance of the service

personalization concept to improve the content

adaptation in ubiquitous scenarios. It consists of

delivering personalized services based on some

specific information, stored in a profile. In order to

support this personalization, they propose a

framework for managing service personalization in a

domain; and the results are documented in a survey

that particularly helped us to improve our work. In

(Hightower and Borriello 2001), the authors present

a set of basic techniques used for location-sensing,

documented in a survey. Moreover, they define how

the taxonomy, defined by them, can be used to

evaluate location-sensing systems.

Despite all the efforts to propose support for

Ubiquitous Computing, there is a lack of approaches

that consider the ubiquitous software development

from the requirements to code. Our main

contribution is offering a set of technological

supports to deal with some ubiquitous applications

challenges and to orient the software engineer in the

systematic development of ubiquitous software. We

documented our approach as a specific ubiquitous

profile (using the building blocks concept) based on

the TROPOS (Giunchiglia et al. 2002) disciplines

and the RUP phases (Kruchten 2003). Details are

presented in Section 4.

3 UBIQUITOUS CHALLENGES

Some challenges commonly found in the ubiquitous

software development are: (i) Heterogeneous

Network: the network can be wire or wireless, and it

can obey different communication protocols (e.g.

DQDB (Distributed Queue Dual Bus), SMDS

(Switched Multimegabit Data Services) and SONET

(Synchronous Optical Network)). Thus, it is

important to establish ways to allow the users’

communication in this heterogeneous medium; (ii)

Geography and Network Topology

: the security in

the communication with heterogeneous mobile

devices is quite different when we analyze it using a

physical or virtual perspective. In Ubiquitous

Computing using the geographical proximity instead

of using the network topology is preferred. The

former guarantees more security and direct

communication; (iii) Limited Battery of the Devices

as the device is dependent on the battery to perform

its basic operations, this feature limits its capacity. It

is necessary to save the device energy as much as

possible. Moreover, it is necessary to have

mechanisms that allow dealing with the

disconnection of the device when the battery is low

or the signal is weak; (iv) Ubiquitous Software

Evolution Need: to attend new market needs, the

devices are constantly adapted, improved and

evolved. Thus, it is necessary that the software,

which is developed based on these devices, has

mechanisms to allow its evolution; (v) Different

Devices: the ubiquitous applications are based on

different devices. Some of them are limited, such as

a simple cellular. Others are powerful such as

desktops and notebooks. Moreover, they have

heterogeneous features in terms of memory and

processing capacity; screen resolution, supported

image types; and others; (vi) Users’ Mobility

: as the

ubiquitous applications offer service/content

anywhere and anytime, the users are in constant

movement. In this context, it is important to consider

technologies to deal with the intrinsic users’

mobility through different smart-spaces; (vii)

Distributed Environment

: the ubiquitous

applications are distributed and complex. They

consider different intelligent environments that are

distributed in the world.

4 OUR PROPOSAL

To deal with different ubiquitous challenges, such as

the ones presented in Section 3, we propose the use

of collaborative software agent communities based

on agents’ intentionality. The agents as a

development paradigm have already demonstrated

their benefits in various applications domains

(Moulin and Chaib-Draa 1996). They can be used as

ICEIS 2009 - International Conference on Enterprise Information Systems

natural abstractions to represent different users in

ubiquitous contexts. Agents can take decisions to

simplify the users’ access to services, contents and

peripheral devices. In this scenario and in order to

emphasize the importance of the agents for

ubiquitous computing development, some

considerations that compose our proposal

hypotheses are presented as follows: (i) Software

agents can asynchronously perform tasks. It is

desired in Ubiquitous Computing to deal with the

challenge “Limited Battery of the Devices,”

presented in Section 3. Moreover, they allow parallel

executions that reduce the user’s waiting time to

receive her/his requests; (ii) Software agents

significantly reduce the data traffic in the network,

because only the processing requests are transmitted

by the network instead of several information

packages. These requests are transferred with the

agents; (iii) Intentional software agents can improve

the user’s satisfaction as they can be responsible for

the content searching, analysis and adaptation

according to the user and device profiles. Moreover,

the agent can easily integrate the user to different

smart-spaces based on the context analysis, and

agent’s beliefs, desires, and intentions. It is

important to consider that the object orientation is

based on the class abstraction that represents a group

or a category. Thus, this abstraction can be used to

satisfy a group but it is not appropriated to satisfy a

specific member of this group. The agent abstraction

can represent a specific member, a specific client, a

specific device, a specific context. Thus, an agent

can be used to satisfy a specific user according to

her/his preferences, device’ features, network

specifications, and contract information instead of a

group of users. Amongst other contributions, this

approach increases the service personalization

possibilities; (iv) Software agents guarantee code

portability (Nakajima et al. 2003 apud Bergenti et

al. 2004). It is important in Ubiquitous Computing

as in this domain the smart-space distribution and

the devices and network heterogeneity are intrinsic.

The code must be portable, allowing the agent to

move/circulate through the network without extra

difficulties. Moreover, agents can perform their

activities independently of the device operational

system; (v) Software agents, based on the agents’

platforms protocols and resources, are uniforms.

They have pre-established communication protocols

and life cycles. These features guarantee the

ubiquitous system stability and avoid problems with

heterogeneous networks; and (vi) Software agents

can be used to improve the security in ubiquitous

applications. As the ubiquitous applications are used

in the people day-to-day activities, it is important

that these applications are prepared to avoid

malicious attacks. An agent can be responsible for

the security. It can be modeled and implemented

considering the security as a quality criterion.

4.1 Case Study Media Shop

The Media Shop project is based on a typically

ubiquitous context, composed of: (i) heterogeneous

devices (e.g. smartphone and palm); (ii) users in

constant movement and with different preferences;

(iii) several offered services and contents; and (iv)

remote servers’ integration need. The main objective

is the media content download through different

devices. The users’ preferences are specified and

stored in a knowledge base. They compose the

user’s profile. The agents consult this base to

improve the service/content searching and

consequentially the users’ satisfaction.

The first solution to develop this project was

based on: (i) the JADE platform (Bellifemine et al.

2007) to support the agents’ implementation; (ii) a

database to store the ubiquitous profiles; (iii) the

Hibernate framework as the persistence layer; and

(iv) the web-service for the implementation of the

offered services such as the users’ registration and

the content download. This solution presents some

deficiencies in the cognitive agents’ development.

According to our experiments the agents’

implementation centered on their behavior showed

itself not adequate to deal with the intentions of the

users. The behavior abstraction is appropriate to

represent user’s behavior and the users also have

intentions, principles and goals. Thus, we have the

necessity to develop more intelligent, autonomous,

flexible, and adaptable agents. We propose the use

of a new technological support (second solution).

The second solution to develop this project was

based on: (i) the JADE-LEAP platform (Caire 2003)

to integrate different devices and smart-spaces; (ii)

the JADEX framework (Pokahr and Braubach 2007)

to support the development of cognitive agents

centered on the BDI model; (iii) the JADEX-JADE

Adapter to allow the integration between the JADE-

LEAP and the JADEX; (iv) a database to store the

ubiquitous profiles; (v) the Hibernate framework as

the persistence layer; (vi) the use of fuzzy rules to

improve the agents’ cognition considering the non-

functional ubiquitous requirements (e.g. user’s

satisfaction, performance, security, price); (vii) a

collaborative and intentional MAS centered on the

negotiation, adaptation and other agents’ properties.

We propose the use of intentional agents to represent

UBIQUITOUS SOFTWARE DEVELOPMENT DRIVEN BY AGENTS' INTENTIONALITY

the users, their devices and different ubiquitous

contexts. We use the BDI model abstractions to

improve the modeling and the development of

cognitive agents’ communities that perform actions,

reason, learn and take decisions according to users’

intentions, goals, beliefs, preferences, needs and

other information capable of facilitating the service

personalization in ubiquitous contexts.

4.2 Case Study DIUP Project

The DIUP project proposes the integration of the

dental and the computing areas to improve the dental

assistance in deprived communities. Different

devices can allow patient registration, treatment

follow-up; diagnosis, drug prescriptions; physician

appointment management, image and registration

searching, and other contributions. Our purpose is to

perform these activities using an intentional MAS.

DIUP imposes various ubiquitous challenges

such as: specific requirements analysis based on the

dental domain; service omnipresence; content

adaptation; different profiles and network

bandwidth; servers overload; users' mobility; and

context awareness. Moreover, there are a lot of

stakeholders involved (e.g. dentists, patients and

attendants); and various smart-spaces (e.g. deprived

communities, hospitals and pharmacies)

Among the technologies used in this project, we

can mention: (i) the i* framework (Yu 1998) to

model the requirements; (ii) a development

environment; (iii) the JADEX to implement

cognitive agents; (iv) the JADE-LEAP to integrate

different devices and the smart-spaces; (v) the

JADEX-JADE Adapter to allow the communication

between the JADE-LEAP and the JADEX; (vi) the

BIGUS fuzzy logic library (Bigus and Bigus 2008)

to improve the implementation of the agents’

cognitive model (their reasoning and learning); and

(vii) the intentional MAS centered on the

negotiation, adaptation and other agents’ properties.

4.3 Systematic Development

We documented the proposed technological support

as a systematic development approach based on the

RUP phases (conceptual, elaboration, construction

and transition,) and the TROPOS disciplines. Thus,

we organized the presentation of our proposal and its

software engineering contributions according to the

TROPOS disciplines: Early Requirements, Late

Requirements, Architectural Design, Detailed

Design, and Implementation. We also incorporated a

discipline to present the testing proposal. We offer

building blocks based on frameworks and models

reuse for each discipline, as presented on Sections

4.3.1 to 4.3.4.

4.3.1 Perform the Early and the Late

Requirements

The ubiquitous applications are very complex.

Therefore, the requirements must carefully be

elicited, modeled, and analyzed. Elicitation

techniques combined with the stakeholders’

interactions are extensile used by the authors and the

collaborators to know the functional and non-

functional requirements of both projects, Media

Shop and DIUP. Moreover, we suggest the

requirements modeling centered on distributed

intentionality, using the i*framework models.

The early requirements discipline consists of the

identification of the main application stakeholders,

which are represented as actors in i* models. It is

also necessary to elicit their goals based on the

activities that they perform or will perform on the

analyzed environment. In the late requirements

discipline, we introduce the system as another actor.

This actor is associated with other stakeholders,

considering the dependencies among them. These

dependencies represent the obligations of the system

towards its environment and actors.

According to our experience using the i*

framework to model our case studies, this modeling

showed itself very adequate: (i) to deal with the

agent’s intentionality properties and the intentional

relationships among different agents; (ii) to present

descriptive models that consider the agent’s strategic

actions can be dynamic and unpredictable; (iii) to

have a semi-formal component for concepts that are

not prepared for formalization (e.g. user’s

satisfaction, security and performance).

Some advantages for using the i* framework

are: the reduction of the quantity of diagrams, which

are commonly used in other modeling proposals

(Bauer and Odell 2005); the functional (Dubois

1989) and non-functional (e.g. softgoals) (Chung et

al. 2000) requirements modeling centered on goal-

orientation that increases the possibilities to

implement traceability policies, and to model agents

that dynamically decide which strategic plans will be

performed according to the user’s profiles, her/his

device profile and contract profile. This latter

advantage increases the possibilities to improve the

user’s service personalization, which is much

desired in Ubiquitous Computing.

The i* uses two types of diagrams to model the

application requirements: (i) the Strategic

ICEIS 2009 - International Conference on Enterprise Information Systems

Figure 1: Smart-Space and Collaboration Representations.

Dependency Model (SD), which describes the

dependences between actors/actors, actors/agents,

and agents/agents in an organizational context; (ii)

the Strategic Rationale Model, which describes the

stakeholders’ interests, and how they can deal with

different software specifications.

The i* framework offers some abstractions for

the goal-oriented modeling, such as actor, agent,

task, goal, softgoal, resources, means-end, and task-

dependency. Details about these abstractions can be

obtained in (Yu 1997). These abstractions are not

sufficient to represent all the concerns of Ubiquitous

Computing for many reasons, such as: (i) i* does not

consider a specific abstraction to represent different

smart-spaces; (ii) i* does not consider a specific

abstraction to represent the intrinsic agent’s

mobility. Thus, our approach suggests some

complementary and specific abstractions for agent-

oriented ubiquitous applications modeling: (a)

Mobile Autonomous Entity

: is an autonomous entity

(reactive or cognitive agent) that is capable to move

from a smart-space to another. We suggest to use the

traditional i* agent abstraction combined to different

tags or stereotypes to classify the agent as fixed or

mobile. In the case of the mobile autonomous entity

it is classified as the mobile stereotype; (b) Smart-

Spaces: are intelligent ubiquitous environments, in

which the actors and the agents perform and

deliberate plans to achieve their goals. We suggest

the box representation (see Figure 1), which delimits

the smart-space that is composed by an agent or an

agents’ community; (c) Collaboration

: is desired

that the agents in ubiquitous context cooperate with

each other to achieve the specified purposes. We

suggest the use of a set of goals, tasks and softgoals

combined to task-decomposition to represent the

collaboration. In order to simplify this

representation, it is recommendable the use of the

capability representation. This representation

encapsulates all the collaboration process. Other

relationships (e.g. negotiation, concurrency, and

adaptation) between the agents can also be

represented using capability. The collaboration

between two agents is also illustrated in Figure 1.

Some other abstractions are presented on our

technical report (

Serrano et al. 2008

), submitted for

IEEE Transactions. Additionally, we are identifying

the different ubiquitous non-functional requirements

(e.g. user’s satisfaction, performance, security, and

service omnipresence), the impact among them, and

ways for operationalizing them using intentional

agents. Details are presented on Section 4.3.2.

4.3.2 Perform the Architectural and the

Detailed Design

The architectural design considers some new

actors/agents and the subgoals/subtasks, which are

associated with these actors/agents and the system in

development. In the detailed design, we detail the

system actors/agents. Thus, the communication

between them and the respective protocol that will

be used to orient it are established. The models

constructed in the early and late requirements are the

main entries of the design disciplines.

In the design disciplines, our approach suggests

some important models, framework and middleware

based on the literature and the experimental results,

obtained in the Software Engineering Laboratory at

PUC-Rio. Some models and frameworks are: the

JADE-LEAP execution modes; the JADEX BDI

model; the Intentional Framework for Content

Adaptation in Ubiquitous Computing (IFCAUC)

(

Serrano et al. 2008

); the incremental spiral model;

and the Softgoal Interdependency Graph (SIG)

(Chung et al. 2000). Our purpose is to assist the

UBIQUITOUS SOFTWARE DEVELOPMENT DRIVEN BY AGENTS' INTENTIONALITY

software engineer to systematically develop

ubiquitous software based on reuse. The JADE-

LEAP platform is basically the JADE used to run in

mobile devices as Personal Java and MIDP devices.

This platform offers two basic execution modes,

called standalone and split modes. The standalone

mode allows integrating the platform and the

Personal Java devices, which are capable of running

the platform container. The split mode allows

integrating the platform and the MIDP devices. In

these devices, as they are limited in memory and

processing capacities, the JADE-LEAP provides a

mechanism to allow the devices to share resources

with a powerful machine. In other words, the limited

devices can run only the “light” part of the

container, called front-end, and the “strong” part,

called back-end, can run in the powerful machine.

For the limited devices, this integration process is

invisible. Thus, using these two modes it is possible

to integrate both, limited and powerful devices, to

the agents’ platform.

The JADEX BDI model

is important to

implement the cognitive agents. The BDI model

considers that the agent is based on its beliefs,

desires, and intentions. This model uses the

abstractions: (i) agents, which represent entities that

perform the actions delegated by the users; (ii)

beliefs, which represent information, knowledge and

physical object of the real world that can be

exchanged among the agents; (iii) desires, which

represent the goals that will be achieved by the

agents; and (iv) intentions, which represent a set of

actions/tasks to achieve the specified goals. This set

of actions/tasks is called plan.

The IFCAUC

is a framework, developed by the

authors, based on an intentional MAS to perform

activities involved in the content adaptation process.

This model recommends, among other technologies,

needs and concepts: (i) the use of different strategies

centered on agents’ intentionality to perform the

content adaptation according to the ubiquitous

profiles and in order to guarantee users’ satisfaction;

(ii) the use of different profiles as a knowledge base

to store the users’ preferences, the access devices’

features, the contract and service information, and

the network specifications; (iii) the use of a MAS

centered on collaboration, negotiation, concurrency

that is improved by reasoning and learning

techniques and the agents’ mobility; and (iv) the use

of a dedicated server to perform the adaptation and

to avoid the application server overload.

The spiral model

, which is used in traditional

application development, is also suggested in our

approach. However, we incorporated the concept of

the incremental software construction in this model.

Thus, in our incremental spiral model, we based the

ubiquitous application development on the

generation of various versions, each more improved

than the last. This incremental principle allows the

evolution and the adaptability of the ubiquitous

software development as errors on the

implementation or on the design can previously be

identified and corrected before the software

deployment. Figure 2 shows this model.

Figure 2: Incremental Spiral Model.

The Softgoal Interdependency Graph (SIG) is

used to formalize the ubiquitous non-functional

requirements (NFRs), the impacts among them, and

ways to operationalize them using an intentional

agent-oriented approach. The main objective is to

provide an adequate support for software engineers

to develop ubiquitous application from the

requirements elicitation to code, considering the

non-functional requirements. Software engineers

frequently forget these requirements. Thus, as our

approach offers a way to deal with these

requirements from the modeling to code, it

considerably increases the relevance of our

systematic development. Figure 3 illustrates some

operationalization for the Satisfaction[User] and

Invisibility[Process Complexity] NFRs.

Figure 3: SIG for Satisfaction and Invisibility.

Additionally, another interesting contribution of

our proposal consists of the associations between the

i*, the BDI, and our approach abstractions (IUSDT).

Figure 4 illustrates some of these associations.

ICEIS 2009 - International Conference on Enterprise Information Systems

Figure 4: Association among Abstractions.

Furthermore, we are developing an ontology for

context aware ubiquitous application to improve and

to standardize the agents’ knowledge base. We also

incorporated, for example, the smart-space and the

profiles abstractions as terms of our ontology. Figure

5 shows the hierarchy of our ontology. Other models

are presented in (

Serrano et al. 2008

and

2008

Figure 5: Ontology Hierarchy.

4.3.3 Perform the Implementation

The implementation discipline depends on the

details specified in the design disciplines. The

TROPOS approach suggests an association between

the detailed design and the implementation template.

The code is added to the template using agent-

oriented programming language supported by a

platform (e.g. JADE-LEAP) or a framework (e.g.

JADEX). The models of the previous disciplines are

the main entries in the implementation.

The support offered by the proposed approach is

centered on framework and middleware reuse.

Therefore, the JADE-LEAP, the JADEX, the

Hibernate, the IFCAUC, and other technological

supports are used in the ubiquitous software

implementation. This technological set has the

responsibility to offer an adequate infra-structure to

solve the main ubiquitous challenges, improving the

software engineering work in the integration of

different devices and smart-spaces; in the users’

mobility, in the cognitive agents development based

on ubiquitous profiles; in the communication,

registration and creation of the agents; in the storage

and recovery of ubiquitous profiles information; in

the adaptation of contents, which are requested in

different access devices anywhere and anytime; and

in the context analysis to facilitate the user’s

integration in different ubiquitous smart-spaces.

Some frameworks (e.g. JADEX and Hibernate)

are under development by important and renowned

Software Engineering research groups. Others, such

as the IFCAUC, are being developed by the authors

to improve the development of intentional

ubiquitous application considering specific

ubiquitous concerns (e.g. content adaptation,

ubiquitous profiles need and context awareness).

Implementation details can also be obtained in

(

Serrano et al. 2008

and 2008

.) As

follows, we briefly describe some ubiquitous

application implementations based on the case

studies presented on Sections 4.1 and 4.2, which are

developed in the Software Engineering Laboratory

at PUC-Rio as experimental researches of our group.

(1) Framework for Media Content Download using

Mobile Devices centered on the Agents’ Behavior

and the Web Service Technology: we develop a

framework for download media contents (e.g. music

and video). The users requested and received the

contents using their own access devices, which

could be limited or not. The main technologies

involved in this implementation were: JADE, web-

service, MAS, user and device profiles. The agents,

according to the implementation model suggested by

the JADE, were based on their behavior. This model,

based on our experimental results, did not allow

improving the agents’ cognition to quite represent

the human intentions in order to guarantee the user’s

satisfaction, and the agents’ autonomy, adaptability

and flexibility.

(2) Ubiquitous Applications instantiated using the

Framework (1): we instantiate the previous

framework to develop three ubiquitous applications.

The first application instantiates the framework to

download the contents using a desktop and a web

interface. Our purpose was testing different powerful

devices with several users’ requests. The desktops

are integrated by the wire network. The second

application instantiates the framework to download

the contents using mobile devices with limited

memory and processing capacities. The third

application instantiates the framework to register the

offered contents and to download the requested

content. According to the performance testing, the

framework agents are very efficient. However, with

regard to the user’s satisfaction, as the cognitive

model is very limited, the results are medium. We

improved this framework by using emergent

technologies, as the ones presented in the next

framework implementation.

UBIQUITOUS SOFTWARE DEVELOPMENT DRIVEN BY AGENTS' INTENTIONALITY

(3) Framework for Media Content Download

centered on the Agents’ Intentionality: in order to

improve the cognitive agents’ model, their

autonomy, flexibility and adaptability, we use

emergent technologies to implement the MAS. Some

of these technologies are: the JADEX and the BDI

model; the JADE-LEAP to integrate different

devices and smart-spaces; ubiquitous profiles (user,

device, contract, network, and content profiles) to

store and to recover specific information to achieve

the user’s satisfaction; the Hibernate as the

persistence layer; fuzzy rules to improve the agents’

reasoning. The first structure layer of our Media

Content Framework represents the interface, in this

case the user and her/his access device. The second

layer is more complex and represents the intentional

MAS. The technological support that comprises this

layer is the JADE-LEAP, the JADEX, the JADEX-

JADE Adapter, and the BDI model abstractions. The

third layer represents the knowledge base, which is

used by the agents to perform the tasks in order to

achieve the goals. The knowledge base is composed

of the agent’s beliefs, the fuzzy rules based on non-

functional ubiquitous requirements, and the

ubiquitous profiles. The agents consult this

knowledge base, improve their reasoning, and

dynamically decide which strategy is the best one to

guarantee the user’s satisfaction and the device

compatibility. In the performance testing, the results

are excellent. The difference in relation to the first

proposed implementation (agents based on behavior)

was in the user’s satisfaction. Using intentionality

and a solid knowledge base, the agents were more

cognitive and it also improves their strategies, which

guarantee and increase the user’s satisfaction.

(4) Framework for Content Adaptation in

Ubiquitous Computing centered on Agents’

Intentionality (IFCAUC): when we defined the

appropriate technologies, we developed a framework

to deal with a specific concern of ubiquitous

applications, the content adaptation. We also

developed a conceptual model to improve the design

and the implementation of the IFCAUC. This

conceptual model is detailed in (

Serrano et al. 2008

Different strategies to improve the agents’

performance and to guarantee the user’s satisfaction

were used in the agents’ implementation. We

structured these strategies in a pyramid

representation (see Figure 6), in which the agents’

first goal is the user’s satisfaction. If it is not

possible to achieve the user’s satisfaction, the agents

perform activities to guarantee device compatibility.

The agents’ intentionality is improved by using the

BDI model. The agents’ knowledge bases are

dynamically updated, which guarantee more realism

in the agents’ decisions. Moreover, we use mobile

agents to perform some complex content adaptations

on a dedicate server. It avoids the application server

overload. We use the capabilities offered by the

JADEX to register and deregister the agents in the

Yellow Pages; to control the agents’ life cycle in the

White Pages; and to improve the agents’ mobility.

These programming practices standardized the

implementation and facilitated the IFCAUC

instantiation.

Figure 6: Strategies Pyramids for Content Adaptation.

(5) Framework for Context Awareness in

Ubiquitous Computing centered on Agents’

Intentionality: we developed a context awareness

framework to allow the analysis of different contexts

and to facilitate the integration of users and smart-

spaces that offer services, and peripheral access. Our

idea is to use agents to represent the users’ interests

and to negotiate with other agents in order to

integrate the user in the smart-spaces.

(6) Applications using Physical Sensors and

Intentional Multi-Agent Systems: we developed

some applications to test different methods of

communication between the users and different

contexts or the users and different devices. We

explored physical sensors such as touch sensor,

presence sensor, sound sensor and light sensor.

4.3.4 Perform the Test

This discipline is dependent on the previous

disciplines. Our approach, as we are following the

TROPOS methodology, suggests the requirements-

driven ubiquitous development. Therefore, we use

the SD and SR models to previously select which

plans will be executed in order to achieve the

specified goals. In this scenario, it is important to

consider, for example: the ubiquitous profiles; the

available technologies; and the non-functional

requirements. Our purpose, based on the

requirements verifiability in high abstraction level, is

to stimulate the ubiquitous software development

centered on quality and in agreement with the users’

interests. Our proposal, combined with the

incremental development, can reduce the test costs

and avoid the need for rigorous validation tests.

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In order to validate our approach, we performed

some experimental tests with the user participation.

The results are promising and confirm the pertinence

of our approach. The first test is performed in the

IFCAUC. We model this framework using agents

and goal-oriented approach. Thus, we verify, by

using a modeling analysis, if each agent’s decision

was according to the ubiquitous requirements.

Additionally, some stakeholders were invited to

participate in the evaluations. Our purpose was the

investigation of users’ satisfaction in the DIUP

application, instantiated using the IFCAUC. Each

stakeholder specifies her/his preferences, which

were stored in the user profile. Moreover, we

requested that each stakeholder used her/his own

access devices. The devices’ features are registered

in the device profile. The dentists requested some

content (e.g. x-ray image) using their devices. The

DIUP application analyzed the requests and returned

the contents, which were adapted according to the

user and device profiles. Therefore, the stakeholders

declared how satisfied they were with the received

content. The main metrics we used are: (i) the

answer time; (ii) the service/content quality; (iii) the

service/content cost; (iv) the security to obtain the

requested content; and (v) the relevancy of the

offered content. Results

: 80% of the users were

Completely Satisfied, 10% were Completely

Satisfied/Very Satisfied

, and 10% were Very Satisfied.

These results demonstrate high indices of users’

satisfaction in relation to the quality and the

relevancy of the requested contents. The

stakeholders also emphasized the DIUP application

performance in quickly answering the requests.

These good results only strengthens the fact of our

proposal is appropriate to ubiquitous software

development as it considers different ubiquitous

profiles, users’ satisfaction, service omnipresence,

agents’ performance, and other requirements that are

commonly found in ubiquitous context.

We also analyzed the agents’ performance using

a log agent, which is responsible to determine the

answer time. This time started when the content was

requested and finished when the adapted content was

sent to the user in her/his device. The contents had

different resolution and adaptation needs. The results

were optimistic, and raised the authors’ confidence

in the proposed approach.

Furthermore, our approach suggests an

automated non-functional (NF) testing using MAS.

We are developing an intentional agent-oriented

framework for NF testing in Ubiquitous Computing.

We will analyze, for example, the ubiquitous

application performance and security using stress

and trustworthiness testing, respectively. We intend

that the agent community generates a report

according to different NF testing.

4.4 Summarizing Our Systematic

Development Proposal

It is important to consider that the emphasis of the

Conceptual Phase

in our proposal is in the Early and

the Late Requirements disciplines, in which we are

concerned about the stakeholders’ interests, the

organization’s policies and the ubiquitous system

that will be implemented. In the Elaboration Phase

our proposal suggest that the software engineer

dedicates her/his time on the Architectural and

Detailed Design disciplines, in which we are

establishing the architectural model and the

technological support that will be used in the

ubiquitous software development. In the

Construction Phase

we are particularly motivated by

the challenges imposed by the Implementation

disciplines, in which we will apply all the conceptual

and technological support, specified in the previous

phases. In the Transition Phase

we concentrate our

attention on testing the ubiquitous software, using

the users’ participation and considering the users’

feedback as a parameter to classify the ubiquitous

software development as a success or not. Figure 7

illustrates these disciplines and phases.

Figure 7: Summarizing Our Systematic Development.

As briefly showed in previous sections, our

systematic development is based on building blocks

for each discipline. For example, the JADE-LEAP is

used to deal with the integration of different devices.

Thus, this platform is part of our Device Integration

Building Block. In other words, we propose a

systematic development using building blocks based

on platforms, frameworks and models reuse.

5 CONCLUSIONS

Ubiquitous Computing encompasses: (i) content

adaptation needs; (ii) integration of devices and

smart-spaces considering the users’ mobility and the

devices’ heterogeneity; (iii) adaptability capacity of

ubiquitous applications in a world in constant

evolution; and others. In order to deal with these

challenges, our proposal investigates traditional and

emergent technologies centered on intentional MAS

to improve the ubiquitous software development.

UBIQUITOUS SOFTWARE DEVELOPMENT DRIVEN BY AGENTS' INTENTIONALITY

The main advantages of MAS include:

autonomy, reactivity, ability to decide without

human interaction; adaptability, mobility,

interactivity, and flexibility. Intentional agents have

all the advantages presented above and also

represent a natural metaphor for human actions as

they can decide centered on their beliefs, desires and

intentions. Thus, we argue that the use of an

intentional MAS seems to be adequate in the

ubiquitous applications development.

Another contribution of our approach proposes

an incremental development for ubiquitous

applications, which is based on reuse. We combined

traditional and emergent technologies to specifically

support the ubiquitous software development, which

is improved using an ontology and fuzzy logic.

As further work, we intend to improve our

approach, incorporating technologies to deal with

the ubiquitous concerns using MAS. The agents’

cognition can be based on special issues on learning

techniques for compositional reasoning

(Giannakopoulou and Păsăreanu 2008) (Upal and

Rogers 2005). It can be a way to discover a new

basis for building intelligent agents. Moreover,

intentional agents can also be considered as planning

systems (Wilensky 1983). We intend to investigate

this research area in Ubiquitous Computing.

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