A stock market decision making makes a compelling case for the use of context aware systems that can adapt to a context behavior known as ‘random walk'. To defend such a proposition the paper adopts the formulation typically used in sensor driven applications that involves critical context characteristics of pervasiveness and instability. From the pervasive perspective the paper concentrates on the ability to characterize a context-state trajectory behavior in real-time to proactively estimate the trend of context change. From the perspective of instability it discusses context related mechanisms such as hedging with derivative instruments as a way to caliber context aware system sensitivity to contextual changes. To validate the idea the paper introduces a special case of an equity option portfolio that is simultaneously delta, gamma and Vega neutral, to deal with extreme context-state exhibiting unpredictable time-varying behavior. Based on some preliminary results of real life experimentation the paper concludes with a continuing current debate on the distinctive merits of reactive versus proactive context.

Personalization using profiles of the users has become an important feature in the fast growing number of e-commerce applications. In current applications, these profiles are usually tailored to the application domains. Therefore separate profiles have to be generated and maintained for each different application domain. Each time a new need arises, users have to reveal their personal details or/and needs to new applications. To overcome this limitation we propose a novel modular user profile, which has layers of information enabling these to be used across multiple application domains. The proposed model consists of three layers where information related to a particular user is separated according to "domain dependence".

User models are important tools for personalization, especially in ecommerce applications. But capturing dynamically changing user needs is a challenge. One of the reasons for such difficulty is that the purchasing behavior of an individual is based on a number of different aspects. In this paper we identify these aspects as a combination of demographics, domain based expectations and transactions. Since each individual can demonstrate a unique combination of these aspects, to achieve finer personalization, such individuality will have to be captured in user models. In this paper we propose such a user model architecture, which also has the ability to self-improve adapting to changes of individual behavior and long term modeling possibilities.

E-commerce has become a common activity among many people. Although widely used, the interfaces which users communicate with e-commerce systems are still at an early stage of development in terms of intelligence and user-friendliness. Unobtrusiveness is recognized as one of the most important desired attributes of an intelligent and friendly interface. In this paper we describe our work on an information architecture to minimize obtrusiveness. A layered information architecture supported by a structured user profile model is described in the paper. As example scenario is presented to clarify the new architecture and the development of a cost model for measuring the level of obtrusiveness is discussed

Context awareness is one of the central features of pervasive computing systems. From pervasive computing perspective a situation can be defined as external semantic interpretation of context. Situation awareness aims to infer situations out of context. Developing situation awareness is a challenging task, which can be significantly hampered by errors during design stage. In this article we propose a novel method for verification of fuzzy situation definitions. Fuzzy logic is a powerful mechanism for reasoning in pervasive computing systems and verification of situation models is a new method of formally ensuring correctness of context awareness and situation awareness. Verification is applied at the design time to check that definitions of situations are error-free. Verification approach allows developers to rigorously specify expected relationships between situations and then formally check that definitions of situations comply with expected relationships. If an error is found, then additional task is to find counterexamples - particular context attribute values, which can cause situation awareness inconsistency. Counterexamples provide additional insight into the cause of error and help repairing situation definitions. We also discuss a method to formalize requirements, as well as propose and formally prove the novel verification algorithm for fuzzy situation models. Last, but not least, we analyze theoretical and practical complexity of the proposed solution.

Pervasive computing solutions are now being integrated into everyday life. Pervasive computing systems are deployed in homes, offices, hospitals, universities. In this work we present ECSTRA – Enhanced Context Spaces Theory-based Reasoning Architecture. ECSTRA is a context awareness and situation awareness framework that aims to provide a comprehensive solution to reason about the context from the level of sensor data to the high level situation awareness. Also ECSTRA aims to fully take into account the massively multiagent distributed nature of pervasive computing systems. In this work we discuss the architectural features of ECSTRA, situation awareness approach and collaborative context reasoning. We also address the questions of multi-agent coordination and efficient sharing of reasoning information. ECSTRA enhancements related to those problems are discussed. Evaluation of proposed features is also discussed.

Context awareness is one of the core features of pervasive computing systems. Pervasive systems can also be improved by smart application of context prediction. This paper addresses subsequent challenge of how to act according to predicted context in order to strengthen the system. Novel reinforcement learning based architecture is proposed to overcome the drawbacks of existing approaches to proactive adaptation. Context spaces theory is used as an example of how existing context awareness systems can be enhanced to achieve proactive adaptation. This recently developed theory addresses problems related to sensors uncertainty and high-level situation reasoning and it can be enhanced to achieve efficient proactive adaptation as well. This article also discusses implementation options and possible testbed to evaluate the solutions

Pervasive computing is a paradigm that focuses on availability of computer resources anytime anywhere for any application and supports non-intrusive integration of computing services into everyday life. Context awareness is the core feature of pervasive computing. High-level context awareness can be enhanced by situation awareness that represents the ability to detect and reason about the real-life situations. In this article we propose, analyze and validate the formal verification method for situation definitions and demonstrate its feasibility and efficiency. Situations are often defined manually by domain experts and are, therefore, susceptible to definition inconsistencies and possible errors, which in turn can cause situation reasoning problems. The proposed method takes as an input properties of situations and dependencies among them as well as situation definitions in terms of low-level context features, and then either formally proves that the definitions do comply with the expected properties, or provides a complete set of counterexamples — context parameters that prove situation inconsistency. Evaluation and complexity analysis of the proposed approach are also presented and discussed. Examples and evaluation results demonstrate that the proposed approach can be used to verify real-life situation definitions, and detect non-obvious errors in situation specifications.

Pervasive computing is a paradigm that focuses on availability and non-intrusive integration of computing services into everyday life. Context awareness is the basic principle of pervasive computing. The important part of high-level context awareness is situation awareness – the ability to detect and reason about the real-life situations. The specifications of situations are often carried out manually by the experts. Therefore, the specification errors can be introduced. The specification errors cause the situation reasoning problems and context model inconsistency. In this article we propose and analyze the approach for formal verification of the situation definitions. Our solution uses as an input the situation specification in terms of low-level context features and the properties under verification, and then either formally proves that the specifications do comply with the expected property, or provide all possible counterexamples – the context conditions that will lead to situation awareness inconsistency. Evaluation and the complexity analysis of the proposed approach are also discussed.

High-level context awareness can be significantly improved by the recognition of real-life situations. The theory of context spaces is a context awareness approach that uses spatial metaphors to provide integrated mechanisms for both low-level and high-level context awareness and situation awareness. Taking context spaces theory situation awareness as a baseline, we propose and analyze the enhanced situation awareness techniques, which allow us to reason about broad class of real-life situations. We also improve reasoning about the relationships between situations, and discuss how it relates to newly proposed situation awareness approaches. Practical evaluation of the results is also discussed.

Mobile devices have access to multiple sources of location data, but at any particular time often only a fraction of the location information sources is available. Fusion of location information can provide reliable real-time location awareness on the mobile phone. In this paper we propose and evaluate a novel approach to detecting the places of interest based on density-based clustering. We address both extracting the information about relevant places from the combined location information, and detecting the visits to known places in the real time. In this paper we also propose and evaluate ContReMAR application - an application for mobile context and location awareness. We use Nokia MDC dataset to evaluate our findings, find the proper configuration of clustering algorithm and refine various aspects of place detection

Context awareness and prediction are important for pervasive computing systems. The recently developed theory of context spaces addresses problems related to sensor data uncertainty and high-level situation reasoning. This paper proposes and discusses componentized context prediction algorithms and thus extends the context spaces theory. This paper focuses on two questions: how to plug-in appropriate context prediction techniques, including Markov chains, Bayesian reasoning and sequence predictors, to the context spaces theory and how to estimate the efficiency of those techniques. The paper also proposes and presents a testbed for testing a variety of context prediction methods. The results and ongoing implementation are also discussed.

This paper presents a mobility management solution to support both applications who are mobility-aware and those who are not. Mobility management in heterogeneous network environments needs to address the double meaning of the IP address as an endpoint identifier and a location identifier. Application-layer mobility use a non-IP endpoint identifier (e.g. user @ realm) while network-layer mobility uses a fixed home IPaddress as endpoint identifier. The resolving of the endpoint identifier to a temporary unicast IP address as location identifier needs support from a mobility management system. This paper proposes a mobility support system that integrates the benefits of application-layer SIP mobility with network-layer MIP mobility. A cross-layer information system provides context for mobility adaptation. Context awareness enhances handover decisions, transport performance and media adoption. The network-layer mobility supports the application to locate the destination ondemand for the initial setup of the sessions. The paper includes an initial evaluation of the network-layer mobility part of the solution.

Pervasive access to the Internet is driven by users who want wireless connectivity to ad hoc as well as infrastructure networks. Multi-hop wireless connectivity widens the coverage areas of access networks and enables two-way wireless traffic into previously dead-spot areas. This paper addresses network mobility issues, which are essential for roaming users who connect to the Internet through wireless access networks. We propose to support connectivity to wired infrastructure through multiple gateways with possibly different capabilities and utilization. Increased network performance can be achieved by adapting to variations in performance and coverage and by switching between gateways when beneficial. We present an efficient solution to enable ad hoc access to the Internet as well as interoperation of reactive routing protocols with Mobile IP. Our solution combines the benefits of proactive agent advertisement and reactive route discovery into a flexible multi-hop access network. We also discuss wireless network metrics that can be used for more intelligent decision making on gateway selection. The feasibility of our approach is validated by simulation and implementation.

The need for maintaining gateway connectivity in an ad hoc access network is vital considering the 80/20 ratio of Internet traffic. There are several proposals of how to integrate gateway forwarding strategies but they all rely on the route discovery procedure of reactive routing protocols. We propose a proactive approach to avoid the delay of the route discovery process. Mobile IP is often suggested to handle macro mobility and we use the advertisements periodically sent by the gateway to update routing tables in the ad hoc network. Since advertisements may arrive to a mobile host through multiple paths, it is important to keep track of the best path to each gateway. We demonstrate the use of a proposed dynamic metric and how to handle location of correspondent hosts. A simulation study demonstrates the usefulness and efficiency of our approach.

With today's heterogeneous access to the Internet, users will move between wired and wireless environments and between infrastructure mode and ad hoc mode of wireless communication. When a mobile node moves from an infrastructure connection and connects multihop to an Internet gateway, the performance will degrade and it may not be able to send all of its traffic via a single gateway. This highlights the need of load-balancing between Internet gateways, especially since the behavior of users today involves a multitude of parallel activities generating multiple flows. This paper proposes a solution that enables distribution of individual traffic flows via different Internet gateways instead of using one single gateway. The proposal includes extensions to Mobile IP in order to handle flow mobility bindings. The performance of the solution is verified by simulation studies.

Organisational memory information systems (OMIS) implement important aspects of organisational memory with the aim of enhancing organisational effectiveness. We propose a three layered framework for a dynamic OMIS. The framework consists of a pragmatic layer to support the actual activity; a conceptual layer to store the concepts (meta knowledge) inherent in that activity; and a process layer to store the experience of performing that activity. Both the conceptual and process layers represent organisational memory repositories in the form of respective models. The implementation of OMIS assumes that any activity is the instantiation of relevant conceptual and process models and includes the reuse of knowledge stored in association with those models. In this way organisational memory is always mapped to current activity, its adequacy constantly evaluated. This provides the potential for the models to evolve as a direct result of the current activity. A partial implementation of this framework to support epidemiological research is illustrated

This paper applies agents to the highly dynamic and variable context of healthcare emergency decision-support domain. More specifically we advocate the use of mobile agents to support the deployment of an ambulance service in real-time. We presented an implementation of the proposed agent based architecture, which was based on the specific functional and non-functional application requirements set out based on thorough analysis of literature. We also created an illustrative emergency scenario in order to demonstrate the validity and feasibility of our proposed model. From the evaluation of the implementation we were able to identify some of the major technical advantages it has to offer as well as challenges one needs to address in similar attempts. We choose mobile agents as the key enabling technology because they offer a single, general framework in which large-scale distributed real-time decision support applications can be implemented more efficiently. Healthcare was chosen as the target application domain to emphasize both the benefits derived from the exploitation of mobile agent paradigm in this domain as well as to demonstrate the benefits of the proposed approach in the highly uncertain context.

Mobile users making real-time decisions based on current information need confidence that their context has been taken into consideration in producing the system's recommendations. This chapter reviews current use of mobile technologies for context-aware real-time decision support. Specifically, it describes a framework for assessing the impact of mobility in decision making. The framework uses dynamic context model of data quality to represent uncertainties in the mobile decision-making environment. This framework can be used for developing visual interactive displays for communicating to the user relevant changes in data quality when working in mobile environments. As an illustration, this chapter proposes a real-time decision support procedure for on-the-spot assistance to the mobile consumer when choosing the best payment option to efficiently manage their budget. The proposed procedure is based on multi-attribute decision analysis, scenario reasoning, and a quality of data framework. The feasibility of the approach is demonstrated with a mobile decision-support system prototype implementation.

Information agents are cooperative agents whose main goal is to collaborate and assist task agents like mobile agents in obtaining information from heterogeneous data sources. Considering the current tools and techniques available in the community, this study sets out to find the practical problems that a developer might encounter in the process of engineering an information agent in the context of a real estate agent HomeBot application. In this technology assessment report, we provide here the approach for circumventing them and document the lessons we have learned. Our assessment is that the construction of an information agent based on current agent building technologies is feasible but not seamless. More importantly, we contend that what is needed is a wholistic tool that integrates smoothly various sub-technologies together. This is not yet provided for in the community and something agent tool builders should address immediately.

With the increased heterogeneity of networked devices integrating into existing distributed file system (DFS) topologies, the ability to balance hardware constraints with user and software requirements is paramount. This is especially true for consistency control in file systems with replication. Exiting DFSs usually implement a single general-purpose consistency approach, focusing on a specific scenario, rather than multitude of possibilities that can arise due to heterogeneity and variability of a mobile computing environments. The developed GLOMAR system cater for the multitude of possibilities by providing the framework to allow numerous consistency control mechanisms specifically built for a scenario to e implemented under the one DFS. This paper discusses the motivation, design, implementation, comparison with similar systems and lessons of GLOMAR. The current implementation of GLOMAR is done in a Microsoft .NET test-bed environment.

Most existing Distributed File Systems (DFSs) implement a single consistency model to maintain one-copy equivalence. The functionality of that consistency model is based on a balance between environmental constraints and the targeted level of consistency. Such systems efficiently maintain consistency while the environmental capabilities remain constant, e.g., presuming uninterrupted connectivity. However, when these characteristics change, the inflexible nature of a single consistency model results in its inability to maintain an expected balance between consistency and constraints. This illustrated with existing implementations of DFSs. GLOMAR is a DFS middleware layer that allows application developers to map their specific consistency models to environmental constraints. As a result, multiple consistency models can be created, with each scoped for a particular application and environmental scenario. This paper outlines important aspects of GLOMAR, detailing its implementation and outlining a number of consistency models.

Efficient support for computational activities in mobile computing environments remains very much a research challenge. This paper discusses the twin-transaction model (TTM) developed for disconnected operation and proposes a novel way to maintain consistency of the TTM mechanism using a component-based mobility-enabled distributed file system platform Glomar. TTM consistency support with Glomar is implemented and demonstrated

Most existing distributed file systems (DFS) implement a single consistency model to maintain one-copy equivalence. The functionality of that consistency model is based on a balance between environmental constraints and the targeted level of consistency. Such systems efficiently maintain consistency while the environmental capabilities remain constant, for example, presuming uninterrupted connectivity. However when these characteristics change, the inflexible nature of a single consistency model results in its inability, to maintain an expected balance between consistency and constraints. GLOMAR is a DFS middleware layer that allows application developers to map their specific consistency models to environmental constraints. As a result, multiple consistency models can be created, with each scoped for a particular application and environmental scenario. The paper outlines important aspects of GLOMAR, detailing its implementation and outlining a consistency model implementation based on Web services and the SOAP protocol.