Costas Kalogiros

Maintaining trustworthiness of socio-technical systems at run-time

Trustworthiness of dynamical and distributed socio-technical systems is a key factor for the success and wide adoption of these systems in digital businesses. Different trustworthiness attributes should be identified and accounted for when such systems are built, and in order to maintain their overall trustworthiness they should be monitored during run-time. Trustworthiness monitoring is a critical task which enables providers to significantly improve the systems’ overall acceptance. However, trustworthiness characteristics are poorly monitored, diagnosed and assessed by existing methods and technologies. In this paper, we address this problem and provide support for semi-automatic trustworthiness maintenance. We propose a trustworthiness maintenance framework for monitoring and managing the system’s trustworthiness properties in order to preserve the overall established trust during run-time. The framework provides an ontology for run-time trustworthiness maintenance, and respective business processes for identifying threats and enacting control decisions to mitigate these threats. We also present use cases and an architecture for developing trustworthiness maintenance systems that support system providers.

An approach to investigating socio-economic tussles arising from building the future internet

With the evolution of the Internet from a controlled research network to a worldwide social and economic platform, the initial assumptions regarding stakeholder cooperative behavior are no longer valid. Conflicts have emerged in situations where there are opposing interests. Previous work in the literature has termed these conflicts tussles. This article presents the research of the SESERV project, which develops a methodology to investigate such tussles and is carrying out a survey of tussles identified within the research projects funded under the Future Networks topic of the FP7. Selected tussles covering both social and economic aspects are analyzed also in this article.

A tussle analysis for information-centric networking architectures

Current Future Internet (FI) research brings out the trend of designing information-oriented networks, in contrast to the current host-centric Internet. Information-centric Networking (ICN) focuses on finding and transmitting information to end-users, instead of connecting end hosts that exchange data. The key concepts of ICN are expected to have significant impact on the FI, and to create new challenges for all associated stakeholders. In order to investigate the motives as well as the arising conflicts between the stakeholders, we apply a tussle analysis methodology in a content delivery scenario incorporating socio-economic principles. Our analysis highlights the interests of the various stakeholders and the issues that should be taken into account by designers when deploying new content delivery schemes under the ICN paradigm.

Supporting Coordinated Maintenance of System Trustworthiness and User Trust at Runtime

In addition to design-time considerations, user trust and the trustworthiness of software-intensive socio-technical systems (STS) need to be maintained during runtime. Especially trust can only be monitored based on the actual usage of the system in operation. Service providers should be able to make informed decisions about runtime adaptation based on trust and trustworthiness, as well as respective essential relations. In this paper we present a unified approach to support the coordination of trust and trustworthiness maintenance. Trustworthiness maintenance is based on measuring objective system qualities, while trust maintenance considers two complementary measures of trust, i.e., the user behavior, and an estimation of the perceived system trustworthiness. A prototype tool demonstrates the feasibility of our approach. Furthermore, we illustrate specific functionalities of the tool by means of an application example.

Computing Trust Levels Based on User’s Personality and Observed System Trustworthiness

In this article, we describe an approach for computing the current trust level of individual users towards an online system and present initial validation results from a small-scale experiment. This trust computational model relies upon survey research for identifying the set of key trust attributes and grouping users into four segments of expected behaviors. Each user’s initial trust level is computed based on a set of assumptions tailored to the specific segment she belongs to, while the trust level evolution takes additionally into account the system outcomes she has experienced so far. More specifically, the trust update follows a machine learning approach, where during the training phase that consists of a small number of system outcomes, users are asked to report their actual trust levels. Finally, we demonstrate the trustors’ segmentation validity and trust estimation accuracy by performing a small-scale experiment in the context of a fictitious online security service.

WOICE: A Decentralized System for Ubiquitous VoIP Services

We propose WOICE (Wireless vOICE), a fully distributed architecture capable of supporting and offering ubiquitous voice services over wireless IP-based data networks. Existing WiFi infrastructure - deployed by enterprises or even individuals - will be supplemented with software modules based on open standards in order to support VoIP. Furthermore, a new breed of VoIP providers by aggregating these currently isolated access networks will be able to offer alternative and advanced services to reachable end-users. These services would in certain cases completely bypass traditional telephony and cellular providers and in others smoothly cooperate with them. We will describe the overall architecture and the necessary modules that should be in place for realizating a system that creates a marketplace for communication services.