Abstract
The GAME2AWE platform aims to provide a versatile tool for elderly fall prevention through exergames that integrate exercises, and simulate real-world environments and situations to train balance and reaction time using augmented and virtual reality technologies. In order to lay out the research area of interest, a review of the literature on systems that provide exergames for the elderly utilizing such technologies was conducted. The proposed use of augmented reality exergames on mobile devices as a complement to the traditional Kinect-based approach is a method that has been examined in the past with younger individuals in the context of physical activity interventions, but has not been studied adequately as an exergame tool for the elderly. An evaluation study was conducted with seniors, using multiple measuring scales to assess aspects such as usability, tolerability, applicability, and technology acceptance. In particular, the Unified Theory of Acceptance and Use of Technology (UTAUT) model was used to assess acceptance and identify factors that influence the seniors’ intentions to use the game platform in the long term, while the correlation between UTAUT factors was also investigated. The results indicate a positive assessment of the above user experience aspects leveraging on both qualitative and quantitative collected data.

Abstract
Pervasive Computing (PerComp) research remains to this date technology-centric, requiring more focus on utilizing human and societal intelligence. To bridge this gap we motivate the need for a conceptual framework that provides a vision for enabling end-users to participate actively in the design of PerComp applications. The framework in particular provides guidance for the development of tools that allow end-users to configure their own smart environments. It emphasizes the benefits of using Smart Objects (SOs) as components of PerComp applications under a system engineering perspective and the benefits of using affordances as dynamic connectable capabilities under a user experience perspective. A generic application model is developed within the framework that manifests the concepts governing the structure and operation of applications composed by connecting SOs together and adhering to a rule-based behavior. A multi-layered software mediator is defined to provide a platform for the runtime support of such PerComp applications. Theoretical foundations for the key concepts adopted regarding the interaction design and system engineering perspectives are discussed and the results of a user evaluation study focusing on the perceived usability of the high-level conceptual models and the developed tools are reported.

Abstract
The Internet of Things (IoT) paradigm advocates the massive use of sensing and communication technologies embedded in the physical world, which provides the potential to collect huge volumes of data and connect them to intelligent systems. As the number of IoT devices is increasing with geometric progress, ensuring interoperability and handling of the big heterogeneous data they generate is of major importance for the development of smart applications and services. In this context, a systematic review of contemporary IoT frameworks based on a multi-level interoperability consideration is performed and findings are critically discussed. Challenges and open issues that emerge in this research area are pointed out, and research opportunities and insights are suggested. Motivated by the shortcomings of the current solutions to support open, interoperable, intelligent and collaborative IoT environments, the concept of Semantic Social Network of Things (SSNT) is introduced. SSNT specifies the integration of device-to-device collaborative services which semantically enable heterogeneous objects to (socially) interact and participate in communities of smart objects. By establishing social relationships and taking collaborative actions, such communities can support users to achieve their goals. A middleware-based framework architecture is presented to enact the SSNT abstraction, and a proof-of-concept application in the smart agriculture domain is outlined to demonstrate important features of this approach.

Abstract
Stress management is related to improved senior well-being and health. The purpose of this work is to identify individual characteristics that suggest the existence of stress and associate these characteristics with features extracted from biometric signals. For identifying these characteristics, on the one hand emotional/psychological measurements are collected using specific questionnaires and on the other hand features are extracted from biosignals collected using wireless sensors. The results of a pilot study with the participation of 12 seniors (mean age 59.7 ±5.8) are reported. Our results indicate that electrodermal activity and heart rate variability features are valid stress indicators for seniors.

Abstract
Ubiquitous Computing, Mobile Computing and the Internet of Things (collectively referred to as UMI herein) involve recent advances in technology areas such as low-cost and miniaturized processing and sensing technologies, high-bandwidth wireless networking and so on. UMI technologies can also support the recent attempts to reform computing education. Yet, to accomplish this potential, relevant UMI learning scenarios are needed. Creating such scenarios can be challenging, since this particular field of computing education is still in its infancy. This paper discusses learning design knowledge which can orientate the future design of UMI learning scenarios. Content analysis was applied on ten quality UMI-oriented learning scenarios. The scenarios were freely accessible in online platforms, and they were designed for middle school education and for the UMI domain. Two different methodological approaches were employed: the first one involved mapping the scenarios to existing predefined learning design elements (i.e. design concepts, design principles, and design patterns). The learning design elements were previously defined in an online database and they involved ubiquitous tools. The second method involved mapping the scenarios to the parameters of a UMI learning ecology. The performed analysis revealed design concepts, principles, patterns and key characteristics underpinning the selected UMI scenarios: they cater for students’ active learning and engage them in interdisciplinary projects in which students are learning across contexts in groups and solve meaningful problems that exploit the functionalities of the UMI technologies. Several recommendations concerning the creation of quality UMI learning scenarios are suggested, such as: striking a balance between conceptual understanding and 21st century lifelong learning skills, highlighting how students’ collaboration is expected to happen in a UMI scenario, providing many opportunities for instructional scaffolding and explicitly mentioning spatiotemporal aspects of the UMI scenarios. These findings could be of interest to computing education researchers, tutors, and curriculum designers who wish to design UMI oriented educational scenarios.

Abstract
This paper describes the design and calibration of a highly accurate temperature measurement system for pervasive computing applications. A negative temperature coefficient (NTC) thermistor with high resistance tolerance is interfaced through a conditioning circuit to a 12-bit digital converter of a wireless microcontroller. The system is calibrated to minimize the effect of component uncertainties and achieves an accuracy of ±0.03 °C on average (±0.05 °C in worst cases) in a 5 °C to 45 °C range. The calibration process is based on a continuous temperature sweep, while calibration data are simultaneously logged to reduce the delays and cost of conventional calibration approaches. An uncertainty analysis is performed to support the validity of the reported performance results. The described approach for interfacing the thermistor to the hardware platform can be straightforwardly adjusted for different thermistors, temperature ranges/accuracy levels/resolutions, and voltage ranges. The low power communication combined with the energy consumption optimization adopted enable an operation to be autonomic for several months to years depending on the application’s measurement frequency requirements. The system cost is approximately $45 USD in components, while its design and compact size allow its integration with extended monitoring systems in various pervasive computing environments. The system has been thoroughly tested and validated in a field trial concerning a precision agriculture application and is currently used in a health monitoring application.

Abstract
Smart mobile devices, due to their ubiquitous nature and high level penetration in everyday life, can be a key component of an Ambient Assisted Living system to improve the quality of life of older people. This paper presents the development and evaluation of Senior App Suite, a system created for assisting seniors’ personal independence and social inclusion. The system integrates mobile computing combined with web and service-oriented technologies to offer a mobile application suite that seniors can easily use to access services, spanning various application areas such as social networking, emergency detection and overall well-being. The research hypothesis is that using such services can be beneficial for decreasing social isolation. There is quantitative indication that this assumption is realistic backed up also by the qualitative analysis from the user’s feedback derived during a pilot study (n = 22) suggesting that Senior App Suite can motivate people in new activities, maintain connection with social ties, give joy and self-confidence, and increase the frequency and quality of social interactions. Our contribution is a detailed methodology spanning the research, design, development, and evaluation of a solution that aims to improve the quality of life of seniors while addressing open issues identified in related initiatives.

Abstract
Engineering of pervasive computing (PerComp) systems is a new scientific field and from an educational perspective needs to draw from a large number of knowledge domains. The appearance of related courses in computer science curricula has a decade history, but the growth of interest has led in recent years to the design of more advanced PerComp educational programs. In this paper we present our experiences in organizing, managing and teaching a PerComp curriculum at a postgraduate level since 2010 using distance learning methodologies in the Hellenic Open University (HOU). We discuss the distinct characteristics and related challenges of distance education and how these characteristics affected program organization, educational material structuring, laboratory courses delivering, and student assessment. We report our main findings and conclusions extracted by an online survey filled by students enrolled in the program, discuss the lessons learned and also provide a number of suggestions for further development.

Abstract
Precision irrigation based on the “speaking plant” approach can save water and maximize crop yield, but implementing irrigation control can be challenging in system integration and decision making. In this paper we describe the design of an adaptable decision support system and its integration with a wireless sensor/actuator network (WSAN) to implement autonomous closed-loop zone-specific irrigation. Using an ontology for defining the application logic emphasizes system flexibility and adaptability and supports the application of automatic inferential and validation mechanisms. Furthermore, a machine learning process has been applied for inducing new rules by analyzing logged datasets for extracting new knowledge and extending the system ontology in order to cope, for example, with a sensor type failure or to improve the accuracy of a plant state diagnosis. A deployment of the system is presented for zone specific irrigation control in a greenhouse setting. Evaluation of the developed system was performed in terms of derivation of new rules by the machine learning process, WSN performance and mote lifetime. The effectiveness of the developed system was validated by comparing its agronomic performance to traditional agricultural practices.

Abstract
Many have attempted to bring the exciting pervasive computing research area into the classroom. Here, we present our experience in organizing and teaching a postgraduate pervasive computing program via distance learning at the Hellenic Open University.

Abstract
In order for Ambient Ecologies (AEs) to provide a viable and functional service to people in their day-to-day lives, it is paramount for the AEs to autonomously learn and adapt to the requirements of the human users living in their everyday environments which are populated with a large number of potentially heterogeneous artefacts/devices (different manufacturers, different descriptions of properties, etc.). In this paper, we will propose the concept of emerging and adaptive fuzzy logic based behaviours which are based on dynamically created activity spheres. We will provide details both on the conceptual notions behind this approach as well as the detailed results from a real world deployment of our proposed system.

Abstract
This paper describes a novel approach to realize symbiotic ecologies within Next Generation Ambient Intelligent Environments (NGAIEs). The proposed approach comprises novel ontology and agent technologies allowing for adaptation on a variety of levels. The metaphor of symbiotic ecologies reflects a meaningful integration of relevant entities (i.e., services, devices, agents) and information within NGAIEs to accomplish a specific user’s task by relying on the symbiotic relationship of the user and his/her intelligent environment. We adopt a service-oriented architecture, combined with (a) intelligent agents that support adaptive task realization and enhanced human-machine interaction and (b) ontologies that provide knowledge representation, management of heterogeneity at user and device level, semantically rich resource discovery and adaptation using ontology alignment mechanisms. In this article, we analyse heterogeneity concerning user behaviour and adaptive user interaction modelling. Furthermore, we focus on heterogeneity regarding the representation of the states of entities and their availability over different networks. The paper will also report on the deployment of a system prototype in a real world setting which is the intelligent flat (iSpace) at the University of Essex.

Abstract
Pervasive Awareness Systems (PASs) collect awareness information from sensors and devices in smart environments and can present it to remote users by using various awareness objects. In this paper, we present a pervasive awareness management framework for supporting the conception, design and realisation of applications that foster social connectedness between communities. The framework consists of • an awareness model that considers user disturbance and privacy • a service-oriented platform that provides core awareness services • assorted tools that support communities to create, adapt and appropriate such applications. A PAS prototype is presented along with a usability evaluation of the tools.

Abstract
An important characteristic of ubiquitous computing (UbiComp) environments is the integration of information, communication and sensing technologies into our everyday objects, giving rise to a new proactive computing model in homes. A smart home uses networked sensors, devices and appliances to build an intelligent environment in which many activities in the home are automated and where devices and services seamlessly cooperate to support domestic tasks. Programming and maintaining such an infrastructure is challenging because suitable abstractions are currently missing. In this work we have attempted to define ambient ecologies as a metaphor for modeling UbiComp applications, specify design patterns and programming principles and develop infrastructure to provide a paradigm of application engineering and tools to support ambient ecology designers, developers and end-users. We describe our model and the middleware architecture and present the engineering of applications in a smart home environment.

Abstract
Our research has been performed in the context of the EU-funded R&D project PLANTS. In this paper, we describe an ontology-driven architecture for developing systems that can be used in precision agriculture applications. Central to our approach is the use of an ontology, which views plants and associated computation as an integral part and allows the interaction of plants and artefacts in the form of synergistic mixed societies. PLANTS ontology sets up a conceptual framework that combines the knowledge about sensors, actuators and other domain concepts available, on the one hand, and the biological studies about plant stressing and sensing mechanisms and consequent plant behaviour, on the other hand, to make plants a proactive component of agricultural systems.

Abstract
As the computer disappears in the environments surrounding our activities, the objects therein become augmented with sensors, actuators, processors, memories, wireless communication modules and they can receive, store, process and transmit information. In addition to objects, spaces also undergo a change towards becoming smart and eventually Ambient Intelligence (AmI) spaces. In order to model the way everyday activities are carried out within an AmI environment, we introduce the notion of ‘‘activity sphere’’. In this paper, we are interested in the ontology-based representation of activity spheres from two different perspectives (as creators and as observers), as well as the modeling and control of the dynamic nature of activity spheres.

Abstract
Given the resulting complexity of the ambient applications that one can form in the Ubiquitous or Pervasive Computing domain it is required to abstract the intricacies of a heterogeneous supporting environment (e.g., intrinsic characteristics of specific communication models) away from the application logic. These applications will be characterized by the increasing ubiquity of interactions between many possibly heterogeneous artifacts and services. This paper presents the Plug/Synapse abstraction, which provides a conceptual model for building ubiquitous computing applications in a high-level programming manner. GAS-OS is the software layer that implements the Plug/Synapse model and the concepts encapsulated in GAS, a generic architectural style, which can be used to describe everyday environments populated with computational artifacts. The paper examines also the design and architecture of GAS-OS, which is the minimum set of modules and functionalities that every device must afford, in order to be a ubiquitous computing artifact and participate in artifact collections.

Abstract
Trip generation is the most time consuming phase in the solution process of crew scheduling problems faced by large transportation companies such as airlines and railways. A large number of trips must be constructed while satisfying a complex set of regulations. In this paper, we present an efficient trip generation method that utilizes originally a rule modeling system in order to reduce the corresponding search space. Special pruning rules are defined using a high-level rule language, which also supports the modeling of the business regulations required in the scheduling process. In addition, the legality checking mechanism involved has been tuned to perform efficiently in order to cope with the vast amount of the legality checks required by the trip generator. The algorithms are tested as a module for a crew scheduling application satisfying the tight response time requirements of a production system. We present experimental results based on problems provided by a major European airline that validate the usefulness and applicability of our work.

Abstract
The day-to-day resource management problem is caused by a set of unexpected events which disturb the planned daily activities and thus change the long-term optimal schedule. The solution to this problem presupposes that all the regulations for the handling of resources in the particular application domain have been satisfied. In this paper, a new approach to handling the rules in the resource management problem is presented. An object-oriented application specific language that allows the flexible expression of the rules, as well as the corresponding rule handling subsystem are presented. The design of the whole system is based on a generic meta-model derived from the object-oriented paradigm. This makes the system applicable to a wide range of problem domains such as repairs management, airline and other transportation scheduling, school scheduling, etc. The system has been developed and tested as a subsystem of the DAYSY system, a day-to-day resource management system for the airline domain.

Abstract
The Internet of Things (ΙοΤ) is a concept that describes the connection of various devices with built-in sensors and communication equipment to achieve the collection and transmission of data in a network. IoT devices are increasing with geometric progress, and ensuring interoperability and handling of the enormous heterogeneous data generated is of major importance for the creation of intelligent applications and services. This paper presents the state of art and current solutions on the issues of interoperability in the IoT domain, as well as the challenges and open issues. Finally, a discussion is provided on what future research should focus on and solutions are outlined to achieve interoperability in IoT systems that can lead to a “Social Network” of Things.

Abstract
Congestive heart failure (CHF) is a progressive condition in which the heart is no longer capable of supplying adequate oxygenated blood to the body. Since the incidence of CHF increases with age, mainly due to the development of heart failure risk factors the epidemic of CHF is expected to grow further in the coming decades and thus becoming an important public health problem. In this paper we present a risk detection system for CHF that uses a Bayesian Network (BN) combined with health measurements that can be taken in a home environment using ambient assisted living technologies. The algorithm is empowered by employing statistical and medical analysis of the stored biological data and the output can be used as a basis for triggering proper preventive interventions. The BN design was established by surveying the relevant literature and consulting the domain expert. The network content combines both biometric variables that are daily monitored and data from patient’s clinical history as well as additional heart failure risk factors in terms of the EuroSCORE model. The predictive validity was tested with the involvement of the domain expert who specified proper validation rules in terms of criteria for detecting a CHF risk.

Abstract
In this paper an approach for building an intelligent tutoring system is presented, based on a multi-agent architecture and combined with ontologies for knowledge representation. The system developed is focused on a bottom up, reactive generation of an active sequence of knowledge units regarding a set of adjustable, high level learning goals. The learning process begins with a set of simple learning goals that require a few learning objects and as the educational process proceeds, the student has to achieve higher learning outcomes that combine other low level outcomes which have been already achieved. The system is able to adapt to student’s learning profile and progress by applying proper learning tactics to prioritize through a weight calculation scheme the sequence of the learning outcomes to achieve. The main components of the system consisting of ontological models of the learner and the subject under study, gateway agents and tutor agents with their core modules (learning space management and learning tactics control) are explained and a detailed description of their interaction is given in the context of an example application. Finally, the advantages of the proposed approach are laid out, especially in the setting of a distance learning education system.

Abstract
In this paper we report on our current research and development work that aims to apply pervasive computing and context-aware technologies to enhance the teaching and learning experience in distance education environments. In order to achieve this goal we move from the 2-D user interfaces found in virtual class management systems to the ubiquitous 3-D environment of the classroom. A smart classroom prototype is presented which provides the necessary mechanisms for building context-aware services to enrich distance learning experience. The fusion of location tracking with activity recognition mechanisms allows to control the liveliness of the video stream transmitted to remote students in order to reduce the gap between physical and virtual classrooms.

Abstract
The use of Precision Agriculture systems is in its infancy in Greece, because of the high fragmented land and the adherence of farmers to traditional farming methods. This paper presents the design, implementation and performance evaluation of an integrated agricultural monitoring and irrigation system using energy-autonomous wireless sensors and actuators. Monitoring and irrigation of the field are carried out through a web application that collects data from a Wireless Sensor Network deployed in a cultivation and displays relative information in real time. Furthermore, the system can operate proactively based on user-defined rules that can decide when the farm should be irrigated. The system is easy to use by farmers who look for a first contact with Precision Agriculture applications. Our results have revealed the possibility to develop a robust, fully-automated, solar powered, and low cost monitoring and irrigation system that suits to the socio-economic conditions of small scale farms in countries like Greece.

Abstract
We are examining in this paper how ubiquitous technology enhanced classrooms can foster opportunities for enhancing teaching and learning. Our concept of Smart Classroom is shaped upon an ambient intelligent environment which supports three major objectives of the educational process: assisting course creation and presentation, classroom management and student assessment and collaboration. Distance learning poses additional requirements on smart classrooms since both local and remote students should have an equal educational experience. This paper describes a Smart Classroom prototype, which combines a number of pervasive computing technologies such as RFId, Microsoft Kinect, magnetic cards and Android applications. The main contribution of our work is combining such different technologies to support classroom attendance management, lecture presentation handling through physical interaction and student collaboration through android applications. Finally, this work includes a survey on related systems and their contribution on strengthening the educational procedure.

Abstract
In this paper, we present an approach to ^p aggregating and using devices that support the everyday life of human users in ambient intelligence environments. These execution environments are complex and changing over time, since the devices of the environments are numerous and heterogeneous, and they may appear or disappear at any time. In order to appropriately adapt the ambient system to a user’s needs, we adopt a service-oriented approach; i.e., devices provide services that reflect their capabilities. The orchestration of the devices is actually realized with the help of Artificial Intelligence planning techniques and dynamic service binding. At design time, (i) a planning problem is created that consists of the user’s goal to be achieved and the services currently offered by the intelligent environment, (ii) the planning problem is then solved using Hierarchical Task Network and Partial-Order Causal-Link planning techniques, (iii) and from the planning decisions taken to find solution plans, abstract service workflows are automatically generated. At run time, the abstract services are dynamically bound to devices that are actually present in the environment. Adaptation of the workflow instantiation is possible due to the late binding mechanism employed. The paper depicts the architecture of our system. It also describes the modeling and the life cycle of the workflows. We discuss the advantages and the limit of our approach with respect to related work and give specific details about implementation. We present some experimental results that validate our system in a real-world application scenario.

Abstract
—Educational process' experimental implementation with the support of Information Communication Technologies (ICT) integrated to the elective course "Principles of Environmental Sciences" of the Second High School Class that combines environmental education, principles of space design, introduction to information technologies in ecology and "green" ICT, and sustainable development through the digital management of planting and of the introduction to the crucial wider issue of precision agriculture. The experimental implementation is realized in collaboration with the professors of the 1rst General High School of Agios Dimitrios. Temperature sensors, humidity and illumination are placed in structures parametrically designed according to the bioclimatic conditions of the space of the school yard and have been sited in accordance with the operational needs of the complex. Students interact with plants and offer maintenance services when plants request it.

Abstract
Ontology and related technologies have been introduced into the Ambient Intelligence domain as a mean to provide declarative formal representations of the domain knowledge. The range of devices available in the scope of an Ambient Intelligence space becomes increasingly heterogeneous and at the same time ubiquitous. Hence there is a need to link the discovery, description and deployment of these ambient devices and their services with context and domain knowledge representations in order to facilitate an Ambient Intelligence space experience. The contribution of this work is an approach for bridging the gap between the non-semantic description mechanisms of XML based devices description protocols, such as UPnP, and the AmI domain knowledge representation. For this we design a prototype ontology-based representation for UPnP devices and services that provide a semantic linking between human-centric abstract description, and the software-centric concrete description that derives from the UPnP descriptors and is necessary to remotely execute method calls on devices. We also demonstrate the benefits of its use with a prototype implementation.

Abstract
Workflows have been used to model repeatable tasks or operations in a number of different industries including manufacturing and software. In this paper we examine the use of workflows to model the interaction of services that can be found in intelligent environments to support user tasks and goals. The deployment of such workflows needs to take care special design considerations, including context awareness, adaptation management, device heterogeneity, and user empowerment. In this paper, we present a framework for the deployment of adaptive workflows. The deployment infrastructure supports BPEL-like, design-time compositions that are complemented by mechanisms for the selection and binding of services at runtime. Workflow behaviour can also adjust dynamically in response to detected changes and unforeseen events by a suit of agents whose initial relationships are specified in the workflows.

Abstract
Awareness systems are a class of computer mediated communication systems that help individuals or groups build and maintain a peripheral awareness of each other. In this paper a service-oriented platform is presented, that supports awareness and informal social communication between community members, distributed over multiple smart home environments. The ASTRA platform, developed in the context of an EU research project, provides a generalized solution to the development of awareness applications that are based on the concept of pervasive awareness, i.e., where awareness information is generated as a result of using personal and home devices and smart objects, which capture and exchange information about the user semi-autonomously.

Abstract
Contemporary software technologies complying with the Service- Oriented Architectural (SOA) paradigm, such as OSGi, UPnP, and the Web services do not meet on their own the adaptability and interoperability challenges of the Ambient Intelligence (AmI) environments. In this paper we present a solution based on the combination of the SOA model with Agents and Ontologies. The agent approach complements the SOA infrastructure by providing high level adaptation to user’s tasks, as an intelligent control layer above SOA. Ontologies are used to tackle the semantic heterogeneity that arises in AmI spaces and provide to agents a common repository of system knowledge, policies and state.

Abstract
Environmental monitoring is a critical process that demands accuracy, reliability and stability at the operation level. Monitoring variables such as temperature, humidity, barometric pressure, soil moisture and ambient light facilitates research in fields such as precision agriculture, habitat monitoring, weather monitoring etc. The use of wireless sensor networks (WSNs) provides a technology solution for dynamic and unattended environmental monitoring, under the condition that requirements such as efficient power management and system robustness are satisfied. This paper presents the design and implementation of a WSN for monitoring environmental variables and evaluates its effectiveness. Based on the acquired experience we describe how we have confronted certain problems such as network synchronization and data consistency and we provide certain design guidelines for building such a system.

Abstract
In the context of the EU funded R&D project ATRACO we are developing a conceptual framework and a system architecture that will support the realization of adap- tive and trusted ambient intelligent systems. Our approach is based on a number of well established engineering principles, such as the distribution of control and the separation of service interfaces from the service implementation, adopting a SOA model combined with intelligent agents and ontologies. Agents support adaptive task realization and enhanced human- machine interaction while ontologies provide knowledge repre- sentation, management of heterogeneity, semantically rich resource discovery and adaptation. ATRACO systems are dy- namic compositions of distributed, loosely-coupled and highly cohesive components that operate in dynamic environments.

Abstract
In this paper we describe the ATRACO (Adaptive and TRusted Ambient eCOlogies) approach towards next generation ambient intelligent environments. Several agents, such as a Fuzzy Task Agent with learning capabilities and an Interaction Agent collaborate in a goal-related Activity Sphere and adapt heterogeneous artifacts within the sphere in order to support the user to fulfill tasks. All components work on a dynamic Sphere Ontology, which forms the main knowledge base of the ecology. The presented prototype is able to realize the Goal “Feel comfortable at home after work” and was implemented in an existing intelligent environment.

Abstract
ATRACO is an EU funded R&D project that considers ambient ecologies consisting of people, context-aware artefacts and digital commodities (e.g., services and content). Members of the ecology are able to adapt to each other and form trusted ad hoc collaborations to achieve specific tasks resulting from the need to serve specific human goals. Our aim is to research the factors and develop the technologies that will lead to the realisation of such ecologies, following an interdisciplinary effort which involves Computer Science, HCI, AI, Control Theory and Sociology. Key factors of the ATRACO problem space to be examined include adaptation, interoperability, user interaction and dynamicity of trust. We focus our efforts on seeking abstractions and mechanisms for establishing trust relationships between its members and on devising adaptation mechanisms based on system behaviour modelling, supervisory control theory of discrete event systems and type-2 fuzzy systems.

Abstract
We are considering a facet of precision agriculture that concentrates on plant-driven crop management. By monitoring soil, crop and climate in a field and providing a decision support system that is able to learn, it is possible to deliver treatments, such as irrigation, fertilizer and pesticide application, for specific parts of a field in real time and proactively. In this context, we have applied machine learning techniques to automatically extract new knowledge in the form of generalized decision rules towards the best administration of natural resources like water. The machine learning application model suggested in this paper is based on an inductive and iterative process of discovering knowledge on the basis of which, patterns and associations having arisen initially are re-examined to expand the pre-existing knowledge. The result of this study was the creation of an effective set of decision rules used to predict the plants’ state and the prevention of unpleasant impacts from the water stress in plants.

Abstract
The ATRACO project uses the ambient ecology metaphor to conceptualize a space populated by connected smart objects and services that are interrelated with each other, the environment and the people. User activities are supported by the implementation of ubiquitous computing applications deployed over this ambient intelligence space. In this paper we present a possible realization of the ATRACO vision using the Connected Home Platform, a commercially available system adopted and evolved by ATRACO in order to provide network adaptation and context-aware services. A flexible and distributed context- aware service model is introduced using the OSGi and UPnP frameworks. UPnP is used to unify the existing network infrastructure comprising of heterogeneous technologies and protocols at the IP level. Furthermore, we introduce a context-aware service model and provide an example of orchestrating context aware services with the support of the platform.

Abstract
Context-aware systems are an emerging genre of computer systems that help add some forms of intelligence to our surroundings. The ATRACO project uses the ambient ecology metaphor to conceptualize a space populated by connected devices and services that are interrelated with each other, the environment and the people, supporting the users’ everyday activities in a meaningful way. Everyday appliances, devices, and context aware artifacts are part of the ATRACO ambient ecologies. In this paper we present the connected home platform adopted by ATRACO and its evolution to provide network adaptation and context-aware services. A flexible and distributed context-aware service model is introduced using the OSGi and UPnP frameworks. UPnP is used to converge the existing network infrastructure comprising of heterogeneous technologies and protocols at the IP level. Furthermore, we introduce a context- aware service model and provide paradigms of context aware services that build upon perceptual and context aware components of the platform.

Abstract
In this paper we discuss research work that enables the development of hybrid systems consisting of communicating plants and artefacts and we in- vestigate methods of creating “interfaces” between artefacts and plants in order to enable people to form mixed, interacting communities. Our research objec- tive is to develop hardware and software components that enable a seamless in- teraction between plants and artefacts in scenarios ranging from domestic plant care to precision agriculture. This paper deals with the approach that we follow for the development of such hybrid systems and discusses both hardware and software architectural aspects, with a special focus on describing the modular platform for wireless sensor network implemented and the distributed context management process followed. The latter imposes a proactive computing model by looping sensor data with actuators through a decision-making layer. The deployment of the system in a precision agriculture application is also presented.

Abstract
Wireless networks allow the deployment of sensing systems and actuation mechanisms at a much finer level of granularity than has been possible before. This paper is focused on connecting sensor data with actuators through a decision-making layer with learning capability. The decision making process regarding the provision of agricultural resources is extended this by on-line monitoring significant plant and environmental parameters and by applying machine-learning algorithms for inducing rules by analysing logged datasets to determine the significant thresholds of plant-based parameters.

Abstract
Several applications, such as precision farming, military field monitoring and seismic activity monitoring require reliable and extended lifetime deployments of potentially a very large number of wireless sensor and actuator nodes. As hardware becomes cheaper and smaller, more of these applications are likely to appear, particularly as these miniaturised nodes offer the opportunity for the electronics to be embedded unobtrusively into everyday objects. This paper will present results from an EU funded project, PLANTS. PLANTS is a research project devising a novel technology that will allow plants to control their own environments. Using this technology, plant signals are detected, analysed and an appropriate response activated. The PLANTS system automatically responds to a plant’s needs.

Abstract
The aim of this work is to bring the Ambient Intelligence (AmI) (1) concept in a new level by introducing it to living organisms – plants. In this paper we provide a concrete scenario where an augmented plant, an ePlant can be incorporated in a ubiquitous computing environment in order to work together with other augmented objects, artifacts, in order to provide to the environment status of its condition. The paper presents the enabling infrastructure and the tools that are used to make such an application, and discusses on how we can make these augmented items to collaborate in order to create mixed societies of plants and artifacts.

Abstract
UbiComp applications operate within an extremely dynamic and heterogeneous environment and have to dynamically adapt to changes in their environment as a result of users’ or other actors’ activities. So context definition, representation, management and use become important factors that affect their operation. To ease the development of such applications it is necessary to decouple application composition from context acquisition and representation, and at the same time provide universal models and mechanisms to manage context. In this paper is presented an approach for building a context-aware UbiComp system organised in hierarchical levels. The focus of the paper is on an ontology-based context modelling, management and reasoning process developed for composing context-aware UbiComp applications from AmI artefacts.

Abstract
Given the resulting complexity of the ambient applications that one can form in the Ubiquitous or Pervasive Computing domain it is required to abstract the intrinsic characteristics of specific communication models away from the application logic. These applications will be characterized by the increasing ubiquity of interactions between many possibly heterogeneous artifacts and services. This paper presents the Plug/Synapse abstraction, which provides a conceptual model for building ubiquitous computing applications in a high-level programming manner. GAS- OS is the software layer that implements the Plug/Synapse model and the concepts encapsulated in GAS, a generic architectural style, which can be used to describe everyday environments populated with computational artifacts. The paper focuses on the design and architecture of GAS-OS, which is the minimum set of modules and functionalities that every device must have, in order to be a ubiquitous computing artifact and participate in artifact collections.

Abstract
In this paper we discuss research work that enables the development of mixed societies of communicating plants and artefacts. PLANTS is an EU- funded Research and Development project, which aims to investigate methods of creating “interfaces” between artefacts and plants in order to enable people to form mixed, interacting (potentially co-operating) communities. Amongst others the project aims to develop hardware and software components that should enable a seamless interaction between plants and artefacts in scenarios ranging from domestic plant care to precision agriculture. This paper deals with the approach that we follow for the development of the homonymous system and discusses its architecture with special focus on describing the communica- tion among artefacts and plants and on designing an ontology that provides a formal definition of the domain under consideration.

Abstract
Ubiquitous computing (UbiComp) applications operate within an extremely dynamic and heterogeneous environment. Thus context definition, representation, management and use become important factors that affect their operation. UbiComp applications have to dynamically adapt to changes in their environment as a result of users' or other actors' activities. To ease the development of such applications it is necessary to decouple application composition from context acquisition and representation, and at the same time provide universal models and mechanisms to manage context. This paper presents experiences with using an ontology to represent context of operation together with decision making for UbiComp applications that result from the composition of functionally independent components. These components were embedded in everyday objects, hence (a) their services were affected by their physical properties, (b) their context of operation was defined by the existence / availability of the objects, and (c) their collective functionality was emerging from a set of interactions among them.

Abstract
An important requirement for ubiquitous computing systems is the support from communication technologies; P2P networking being the primary candidate. This paper presents a P2P communication architecture that reflects upon a plug/synapse model. The proposed architecture is part of GAS (Gadgetware Architectural Style), a generic architectural style, which allows computational artefacts (eGadgets), to be easily combined into meaningful configurations by users. The plug/synapse model provides the necessary conceptual abstractions to access uniformly eGadget’s services and capabilities in order to realize a collective behavior. The implementation of the architecture consists of algorithms and protocols for wireless, connectionless communication as well as mechanisms for internal diffusion of information exchanged.

Abstract
Trip generation is the most time-consuming phase of the crew scheduling process. A large number of trips must be constructed while satisfying a complex set of regulations. In this paper, we present an efficient trip generation method that utilizes effectively a legality checking system in order to reduce the corresponding search space. Special pruning rules are defined using a high-level rule language, which also supports the modeling of the business regulations required in the scheduling process. In addition, the legality checking mechanism has been tuned to perform efficiently in order to cope with the vast amount of the legality checks required by the trip generator. The algorithms are tested as a module for a crew re-scheduling application satisfying the tight response time requirements of a production system. We present experimental results based on problems provided by a major European airline that validate the usefulness and applicability of our work.

Abstract
Crew-pairing optimization involves the creation of a feasible and as close to optimum set of trips that cover all the flying activity of an airline. The problem is NP- complete which makes it computationally intractable and its solution requires specialized algorithms and heuristics. A major goal of the HPCN Esprit project PAROS is to improve the speed of the crew-pairing optimization process for the solution of very large problems. In this paper the ability to efficiently solve large crew pairing problems on a network of workstations (NOW) is presented. The main components of the crew-pairing optimization process are the pairing generator and the pairing optimizer. Large crew pairing problems from Lufthansa have been solved with a near linear speedup on the generator and satisfactory results on the optimizer.

Abstract
The present state of communication networks with respect to speed and reliability and the recent growth of distributed applications have created a need for a global enterprise solution to the legality checking and attribute evaluation requirement. Traditionally, the mainframe systems provided the cohesion of all the processes with respect to the company regulations. When decentralized systems and applications became widely used the legality checking mechanism lost its central role and became a necessary component for every decentralized system. In this paper a methodology to reconnect these systems with respect to their legality checking and attribute evaluation needs is presented. A generic Legality Checking system has been developed and integrated with scheduling systems of the airline domain. It is shown that the client- server model adopted can bring back in a flexible manner the lost homogeneity of the central legacy systems.

Abstract
The crew planning problem has been successfully solved on a loosely connected network of workstations (NOW) using advanced computational techniques and efficient communication patterns. The parallelization of the successful sequential system of Carmen Systems AB guarantees that the results are immediately useful and applicable to a large number of airlines scheduling problems. The parallel pairing generator component of the crew scheduling process achieves a linear speedup on the number of processors and can be efficiently scaled to a large number of processors. The novel parallel optimizer approach of the paper also achieves almost linear speedups for large problems solved on a small number of workstations. The Lufthansa problems that were used in our experiments validate our theoretical results and prove the value and usefulness of our work.

Abstract
We give an overview of the parallelization work done in PAROS. The specific parallelization objective has been to improve the speed of airline crew scheduling, on a network of workstations. The work is based on the Carmen System, which is used by most European airlines for this task. We give a brief background to the problem. The two most time critical parts of this system are the pairing generator and the optimizer. We present a pairing generator which distributes the enumeration of pairings over the processors. This works efficiently on a large number of loosely coupled workstations. The optimizer can be described as an iterative Lagrangian heuristic, and allows only for rather fine-grained parallelization. On low-latency machines, parallelizing the two innermost loops at once works well. A new "active-set" strategy makes more coarse- grained communication possible and even improves the sequential algorithm.

Abstract
In this paper the ability to efficiently solve large crew scheduling problems on a network of workstations (NOW) is presented. Large crew scheduling problems from the Lufthansa set of problems have been solved with a near linear speedup on the generator component of the problem. The generator is the most time consuming component of the solution process, which implies that a significant improvement of the overall solution process is possible. This paper presents the first tangible results of the HPCN Esprit project PAROS, where the complete crew scheduling procedure on a NOW is parallelized and extended.