A Privacy Type System for Context-aware Mobile Ambients

Thanks to the advances in technologies, ubiquitous computing (ubicomp) is developing fast with the proliferation of smart devices such as smart phones and tablet computers. However, privacy is an important concern in ubicomp; unless users are confident enough that their privacy is protected, many will be deterred from using such systems. This paper proposes a privacy type system that controls the behaviour of concurrent, context-aware and mobile processes to ensure that private information are not accidentally disclosed. We prove the subject reduction property, which guarantees that a well-typed process is safe and cannot disclose private information to an unauthorised party

On Recommendation of Learning Objects using Felder-Silverman Learning Style Model

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The e-learning recommender system in learning institutions is increasingly becoming the preferred mode of delivery, as it enables learning anytime, anywhere. However, delivering personalised course learning objects based on learner preferences is still a challenge. Current mainstream recommendation algorithms, such as the Collaborative Filtering (CF) and Content-Based Filtering (CBF), deal with only two types of entities, namely users and items with their ratings. However, these methods do not pay attention to student preferences, such as learning styles, which are especially important for the accuracy of course learning objects prediction or recommendation. Moreover, several recommendation techniques experience cold-start and rating sparsity problems. To address the challenge of improving the quality of recommender systems, in this paper a novel recommender algorithm for machine learning is proposed, which combines students actual rating with their learning styles to recommend Top-N course learning objects (LOs). Various recommendation techniques are considered in an experimental study investigating the best technique to use in predicting student ratings for e-learning recommender systems. We use the Felder-Silverman Learning Styles Model (FSLSM) to represent both the student learning styles and the learning object profiles. The predicted rating has been compared with the actual student rating. This approach has been experimented on 80 students for an online course created in the MOODLE Learning Management System, while the evaluation of the experiments has been performed with the Mean Absolute Error (MAE) and Root Mean Square Error (RMSE). The results of the experiment verify that the proposed approach provides a higher prediction rating and significantly increases the accuracy of the recommendation

Formal Specification of CA-UCON model using CCA

A Context-Aware Usage CONtrol (CAUCON) model is an extension of the traditional UCON model which enables adaptation to environmental changes in the aim of preserving continuity of usage in a pervasive computing system. When the authorisations and obligations requirements are met by the subject and the object, and the conditions requirements fail due to changes in the environment or the system context, CAUCON model triggers specific actions to adapt to the new situation. Besides the data protection, CA-UCON model so enhances the quality of services, striving to keep explicit interactions with the user at a minimum. This paper proposes a formal specification of the CA-UCON model in the Calculus of Context-aware Ambients (CCA in short). This enables formal analysis of the CA-UCON model using the execution environment of CCA. For illustration, some properties of the CA-UCON model are validated for a ubiquitous learning system

Formal Specification of a Context-aware Whiteboard System in CCA

A context-aware whiteboard system provides a number of services in a smart classroom including registering students as they enter the classroom; logging students and lecturers in to the blackboard virtual learning environment at the beginning of each lecture and logging them out at the end of the lecture. This system also notifies students of their absence to a lecture and maintains a list of attendance automatically. Using information from the timetable, it is aware of the lectures that are scheduled to take place in the classroom and the students that are allowed to attend these lectures. Finally, it allows students and lecturers to interact with teaching materials such as lecture slides and videos stored in the blackboard virtual learning environment. This paper proposes a formal specification of the white board system in the Calculus of Context-aware Ambients (CCA in short). This enables the formal analysis of the white board system using the execution environment of CCA. Some important properties of a classroom white board system have been validated as a proof of concept

An Extension of Class Diagram to Model the Structure of Context-Aware Systems

Context-aware systems (CASs) have become a reality thanks to the development of smart software and hardware to assist the users in various real life activities. The proliferation of context-aware services has led to the emergence of environments where services are made available for usage anywhere and at any time. CASs have the ability to capture users’ contexts and use their instance values to provide self-adaptive services in response to context changes. Modelling and documenting the structure of such a system during the design phase is vital for system validation, testing, maintenance and version management. The Unified Modelling Language (UML) is the de facto industrial standard for system modelling and development. The UML class diagrams provide notations for modelling graphically the structure of a system in terms of classes and the relationships between them. However, these notations are insufficient to model the structure of CASs. This paper proposes a new set of notations to represent context and context-awareness and their relationships with classes in class diagrams. Hence, the structure of CASs can be specified, visualized, constructed, and documented distinctively during system development. The proposed approach is evaluated using real-world case studies

From Use Case Diagrams to Executable Context-aware Ambients

This paper proposes an approach to translating a use case diagram into an executable context-aware ambients. The requirements of a context-aware system is captured and represented in an extension of UML use case diagrams called context-aware use case diagrams. Then an algorithm is proposed that translate a context-aware use case diagram into a process in the Calculus of Context-aware Ambients (CCA). This process can then be analysed using the CCA simulator. The proposed approach is evaluated using a real-word example of a context-aware collision avoidance system

An Extension of the Use Case Diagram to Model Context-aware Applications

Context-aware applications have the ability to sense the context of the user and use the sensed context information to make adaptation decision in response to changes in the user’s context. Hence, besides the functional requirements, context-awareness is an important requirement of such applications. Although, the use case diagram of the Unified Modeling Language (UML) is considered as the industrial de-facto standard for modeling the functional requirements of applications, it is insufficient to accurately capture context-awareness requirements. This paper proposes an extension of the use case diagram with new notations to cater for the modeling of context-aware applications. The proposed extension called context-aware use case diagram is more expressive and enables a clear separation of concerns between context-awareness requirements and functional requirements which is helpful during requirements capture and analysis of large scale or complex context-aware applications

Towards Monitoring Security Aspects in Mobile Grid Computing Systems: a Survey

— In recent years, the proliferation of mobile devices has led to the emergence of mobile grid computing, that is extending the reach of grid computing by enabling mobile devices both to contribute to and utilise grid resources. Thus, the pool of available computational and storage resources can be significantly enriched by leveraging idle capacities of mobile devices. Nevertheless, the emergence of the mobile grid gives rise to challenges, which have not hitherto been addressed thoroughly. Among those is the security threat, which arises from the multitude of mobile devices accessing grid resources and associated network connections, spanning across the globe. Accordingly, the aim of this paper is two-fold. First, it surveys prominent grid monitoring systems and attempts to identify any potential limitations with respect to the security aspect. The results of the survey indicate that existing solutions fail to address the security concerns, which arises from enabling the mobile devices interacting with the grid. To this end the second aim of the paper is to propose a monitoring system which continuously tracks the geo-location of the mobile devices accessing the grid and thereby ascertains that the location-based security policies are not violated

Towards Monitoring Security Policies in Grid Computing: a Survey

Grid computing systems are complex and dynamic environments and therefore require appropriate automated management, which would enable stable and reliable operation of the whole grid environment. The research community has addressed this requirement with a number of monitoring frameworks, which serve to collect data at various levels to support decision taking and management activities within grids. However, these existing solutions seem to implement little support for collecting security-related data and enforcing appropriate security policies and constraints in this respect. With an increasing role of network connections and users remotely accessing computational resources from various locations, grid systems are no longer seen as localised and isolated ecosystems, but are coming to be more open and distributed. In this light, it is becoming more and more important to enable monitoring framework with capabilities to collect security-related data and check whether these observations comply with certain security constraints. Accordingly, in this paper we present a survey of existing grid monitoring systems with a goal to identify an existing gap of insufficient support for handling the security dimension in grids. Our survey suggests that available grid monitoring frameworks are incapable of collecting security-related data metrics and evaluating them against a set of security policies. As a first step towards addressing this issue, we outline several groups of security policies, which we envisage to be further incorporated in our own research work, and by the wider community

Quality Properties of Execution Tracing, an Empirical Study

The authors are grateful to all the professionals who participated in the focus groups; moreover, they also express special thanks to the management of the companies involved for making the organisation of the focus groups possible.Data are made available in the appendix including the results of the data coding process.The quality of execution tracing impacts the time to a great extent to locate errors in software components; moreover, execution tracing is the most suitable tool, in the majority of the cases, for doing postmortem analysis of failures in the field. Nevertheless, software product quality models do not adequately consider execution tracing quality at present neither do they define the quality properties of this important entity in an acceptable manner. Defining these quality properties would be the first step towards creating a quality model for execution tracing. The current research fills this gap by identifying and defining the variables, i.e., the quality properties, on the basis of which the quality of execution tracing can be judged. The present study analyses the experiences of software professionals in focus groups at multinational companies, and also scrutinises the literature to elicit the mentioned quality properties. Moreover, the present study also contributes to knowledge with the combination of methods while computing the saturation point for determining the number of the necessary focus groups. Furthermore, to pay special attention to validity, in addition to the the indicators of qualitative research: credibility, transferability, dependability, and confirmability, the authors also considered content, construct, internal and external validity