Trust Evaluation of a System for an Activity

International audienceWhen users need to perform a digital activity, they evaluate available systems according to their functionality, ease of use, QoS, and/or economical as- pects. Recently, trust has become another key factor for such evaluation. Two main issues arise in the trust management research community. First, how to de- fine the trust in an entity, knowing that this can be a person, a digital or a physical resource. Second, how to evaluate such value of trust in a system as a whole for a particular activity. Defining and evaluating trust in systems is an open problem because there is no consensus on the used approach. In this work we propose an approach applicable to any kind of system. The distinctive feature of our pro- posal is that, besides taking into account the trust in the different entities the user depends on to perform an activity, it takes into consideration the architecture of the system to determine its trust level. Our goal is to enable users to have a per- sonal comparison between different systems for the same application needs and to choose the one satisfying their expectations. This paper introduces our approach, which is based on probability theory, and presents ongoing results

Graph-Based Trust Model for Evaluating Trust Using Subjective Logic

50 pagesBefore using a digital system, it is necessary to evaluate it according to different parameters. Lately trust emerged as a momentous aspect of evaluation. Evaluating trust in a system is a complex issue that becomes more challenging when systems use distributed architectures. In a previous work, we proposed SocioTrust, a trust model that is based on probability theory to evaluate trust in a system for an activity. In SocioTrust, trust values are considered as the probability, by which a trustor believes that a trustee behaves as expected. A limita- tion of using traditional probability is that users cannot express their uncertainties about some actors of their activity. In real situations, not everyone is in possession of all the necessary information to provide a dogmatic opinion about something or someone. Subjective logic thus emerged to facilitate the expression of trust as a subjective opinion with degrees of uncertainty. In this paper, we propose SubjectiveTrust, a graph-based trust model to evaluate trust in a system for an activity using subjective logic. The distinctive features of our proposal are (i) user's un- certainties are taken into account in trust evaluation and (ii) besides taking into account the trust in the different entities the user depends on to perform an activity, it takes into consideration the architecture of the system to determine its trust level

System Modeling and Trust Evaluation of Distributed Systems

International audienceNowadays, digital systems are connected through complex architectures. These systems involve persons, physical and digital resources such that we can consider that a system consists of elements from two worlds, the social world and the digital world, and their relations. Users perform activities like chatting, buying, sharing data, etc. Evaluating and choosing appropriate systems involve aspects like functionality, performance, QoS, ease of use, or price. Recently, trust appeared as another key factor for such an evaluation. In this context, we raise two issues, (i) how to formalize the entities that compose a system and their relations for a particular activity? and (ii) how to evaluate trust in a system for this activity? This work proposes answers to both questions. On the one hand, we propose SOCIOPATH, a metamodel based on first order logic, that allows to model a system considering entities of the social and digital worlds and their relations. On the other hand, we propose two approaches to evaluate trust in systems, namely, SOCIOTRUST and SUBJECTIVETRUST. The former is based on probability the- ory to evaluate users’ trust in systems for a given activity. The latter is based on subjective logic to take into account uncertainty in trust values

Closed-loop stimulation for upper limb rehabilitation following spinal cord injury and stroke

PhD ThesisInnovation is required to improve upper limb rehabilitation for neurological conditions such as stroke and spinal cord injury (SCI). There is growing appreciation of the importance of neural plasticity in recovery, and how this can be facilitated by synchronous activity in peripheral neural circuits and central brain areas. However, despite increasing scientific evidence, technological solutions that exploit associative plasticity have not yet been widely evaluated in clinical practice. In this thesis, I report the development and initial evaluation of a novel device which enabled a reaching and grasping motion in the affected limb by combining assistive functional electrical stimulation (FES) with inferred voluntary brain activity. The device was designed to enable translation from laboratory-to-clinic by overcoming common practical barriers to translational research, such as adaptability and ease of use. The device was demonstrated to be usable by individuals with either chronic stroke or SCI, and received positive qualitative feedback. Some participants showed modest improvements on assessments of upper limb function following a short intervention period. A study with healthy able-bodied volunteers indicated that after using the device, corticospinal pathways to the antagonist (flexor) muscle may be facilitated, and this facilitation might be increased by adjusting the relative timing of stimulation and inferred brain activity. The device could also deliver alternative stimulation techniques, and an exploratory study into transcutaneous spinal cord stimulation (tSCS) was conducted with healthy able-bodied volunteers. It was found that tSCS may activate peripheral and spinal pathways within acceptable comfort levels, but the parameters used in this study did not to generate functional contractions. An unexpected oscillatory motor response provided insights into how tSCS acts upon the motor system. Prior to a large scale evaluation of clinical effectiveness, further research is required to: further develop a theoretical basis for the intervention; demonstrate the mechanisms of action; and to evaluate the efficacy of the device.Wellcome Trust, postgraduate research studentship (2015 to 2018) • EPSRC Preparing for GCRF Award (PI: Dr Andrew Jackson) - Low cost rehabilitation of hand function following stroke (2016 to 2017

The Macro-Social Benefits of Education, Training and Skills in Comparative Perspective [Wider Benefits of Learning Research Report No. 9]

This report, the second from the Centre's strand of comparative research, complements an earlier WBL research report (Education, Equity and Social Cohesion: A Distributional Model) in exploring further themes of societal comparison and the distributional effects of education systems. Despite generally high levels of educational attainment there is huge diversity amongst Western Societies in terms of crime, tolerance, trust and social cohesion. In this report, we take a comparative approach to investigating relationships between education and these outcomes at a societal level. Through an interdisciplinary review of literatures from sociology, history, economics and psychology we examine the role of education systems from a number of countries in influencing trends in, and levels of, these variables. Whilst the importance of country and historical context is stressed throughout we arrive at some general conclusions concerning the role of education systems in the development of various forms of social cohesion. This report will be of interest to policy makers, researchers and practitioners who are interested in the social impact of education systems. In particular, we examine implications for current UK policy targeted at increasing national educational attainment