CSD's Publications

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  • Item
    A model of social responsibility for start-ups: developing a cross-fertilisation of responsible innovation, the lean start-up approach, and the quadruple helix approach
    (Taylor & Francis Online, 2023-10-11) Ryan, Mark ; Popa, Eugen Octav ; Genovese Andrea ; Berliri, Maresa ; Alfonsi, Alfonso ; Veloudis, Simeon
    In this paper, we cross-fertilise responsible innovation (RI), the Lean Start-up approach (LSA) and the Quadruple Helix approach (QH) within one model: the social responsibility for start-ups model (SRSM). SRSM aims to instil responsibility into the start-up innovation process by ensuring that the voices of stakeholders from all four helices are taken into account, whilst providing an assessment of current impacts in these areas compared with the ambition of start-ups. This helps to identify room for improvement in order to provide an iterative, lean approach for start-ups to inform the strategy of the start-up cycle, which incorporates the four helices of the QH, and the four process requirements found in RI theory (anticipation, reflexivity, inclusiveness, and responsiveness). This model works as a way to operationalize responsibility in start-ups. This paper fills a gap where there is a lack of suitable approaches for start-ups to follow and implement.
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    A model of social responsibility for start-ups: developing a cross-fertilisation of responsible innovation, the lean start-up approach, and the quadruple helix approach
    (Informa UK Limited, 2023-10-11) Veloudis, Simeon ; Ryan, Mark ; Popa, Eugen Octav ; Declich, Andrea ; Blok, Vincent ; Berliri, Maresa ; Alfonsi, Alfonso
    In this paper, we cross-fertilise responsible innovation (RI), the Lean Start-up approach (LSA) and the Quadruple Helix approach (QH) within one model: the social responsibility for start-ups model (SRSM). SRSM aims to instil responsibility into the start-up innovation process by ensuring that the voices of stakeholders from all four helices are taken into account, whilst providing an assessment of current impacts in these areas compared with the ambition of start-ups. This helps to identify room for improvement in order to provide an iterative, lean approach for start-ups to inform the strategy of the start-up cycle, which incorporates the four helices of the QH, and the four process requirements found in RI theory (anticipation, reflexivity, inclusiveness, and responsiveness). This model works as a way to operationalize responsibility in start-ups. This paper fills a gap where there is a lack of suitable approaches for start-ups to follow and implement.
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    A Novel Permission Hierarchy for RBAC for Dealing with SoD in MAC Models
    (Oxford Academic, 2016-04) Veloudis, Simeon ; Nissanke, Nimal
    Separation of duty (SoD) is a fundamental principle of computer security that has not been addressed sufficiently in multi-level security (MLS) mandatory access control (MAC) models, as realized through the adoption of the Bell-LaPadula (BLP) model. This is due to the lack of means at present to express SoD constraints in MAC. The primary objective of this paper is to overcome this but within a framework that allows for rigour and linguistic features to express SoD constraints, while retaining the core security properties of BLP, namely the Simple Security Property and ★-Property. To this end, we propose a formal framework which bridges the BLP model with the more general hierarchical role-based access control (RBAC) model. Our framework is based on a hierarchy of permissions that is founded on a novel concept of permission capacity, determined on the basis of the security levels that characterize objects in MLS models. Such a hierarchy naturally provides a solid basis for defining role seniority and deriving a hierarchical ordering on roles within MLS models. SoD constraints are expressed by means of conflicting permissions that give rise to mutually exclusive roles.
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    Achieving security-by-design through ontology-driven attribute-based access control in cloud environments
    ( 2019-04) Veloudis, Simeon ; Paraskakis, Iraklis ; Petsos, Christos ; Verginadis, Yannis ; Pationiotakis, Ioannis ; Gouvas, Panagiotis ; Mentzas, Grigoris
    The constantly increasing number of cyberattacks worldwide raise significant security concerns that generally deter small, medium and large enterprises from adopting the cloud paradigm and benefitting from the numerous advantages that it offers. One way to alleviate these concerns is to devise suitable policies that infuse adequate access controls into cloud services. However, the dynamicity inherent in cloud environments, coupled with the heterogeneous nature of cloud services, hinders the formulation of effective and interoperable access control policies that are suitable for the underlying domain of application. To this end, this work proposes an approach to the semantic representation of access control policies and, in particular, to the semantic representation of the context expressions incorporated in such policies. More specifically, the proposed approach enables stakeholders to accurately define the structure of their policies, in terms of relevant knowledge artefacts, and thus infuse into these policies their particular security and business requirements. This clearly leads to more effective policies, whilst it enables semantic reasoning about the abidance of policies by the prescribed structure. In order to alleviate the scalability concerns associated with semantic reasoning, the proposed approach introduces a reference implementation that extends XACML 3.0 with an expert system fused with reasoning capabilities through the incorporation of suitable meta-rules. Keywords: Context-aware security; Ontologies; Access control policies; Data privacy; Security-by-design; Semantic reasoning
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    An Ontological Framework for Determining the Repercussions of Retirement Actions Targeted at Complex Access Control Policies in Cloud Environments
    ( 2017-12) Veloudis, Simeon ; Paraskakis, I. ; Petsos, Christos
    Veloudis S., Paraskakis I., Petsos C., (2017). An Ontological Framework for Determining the Repercussions of Retirement Actions Targeted at Complex Access Control Policies in Cloud Environments, Proceedings of the10th International Conference on Utility and Cloud Computing (UCC) pp 21-28, Austin, Texas, USA — December 05 - 08, 2017
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    An Ontological Framework for Reasoning about Relations between Complex Access Control Policies in Cloud Environments
    ( 2019-05) Veloudis, Simeon ; Paraskakis, I. ; Petsos, Christos
    By embracing the cloud computing paradigm enterprises are able to realise significant cost savings whilst boosting their agility and productivity. Yet, due mainly to security and privacy concerns, many enterprises are reluctant to migrate the storage and processing of their critical assets to the cloud. One way to alleviate these concerns, hence bolster the adoption of cloud computing, is to infuse suitable access control policies in cloud services. Nevertheless, the complexity inherent in such policies, stemming from the dynamic nature of cloud environments, calls for a framework capable of providing assurances with respect to the effectiveness of these policies. The work presented in this paper elaborates on such a framework. In particular, it proposes an approach for generically checking potential subsumption relations between access control policies that incorporate the contextual knowledge that characterises an access request and which needs to be taken into account for granting, or denying, the request. The proposed framework is expressed ontologically hence enabling automated reasoning, through semantic inferencing, about policy subsumption.
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    An Ontological Template for Context Expressions in Attribute-Based Access Control Policies
    ( 2017-04) Veloudis, Simeon ; Paraskakis, I. ; Petsos, Christos ; Verginadis, Yannis ; Pationiotakis, Ioannis ; Mentzas, Grigoris
    By taking up the cloud computing paradigm enterprises are able to realise significant cost savings whilst increasing their agility and productivity. However, due to security concerns, many enterprises are reluctant to migrate their critical data and operations to the cloud. One way to alleviate these concerns is to devise suitable policies that infuse adequate access controls into cloud services. However, the dynamicity inherent in cloud environments, coupled with the heterogeneous nature of cloud services, hinders the formulation of effective and interoperable access control policies that are suitable for the underlying domain of application. To this end, this work proposes an ontological template for the semantic representation of context expressions in access control policies. This template is underpinned by a suitable set of interrelated concepts that generically capture a wide range of contextual knowledge that must be considered during the evaluation of policies.
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    BRIDGING THE GENDER GAP IN STEM DISCIPLINES: AN RRI PERSPECTIVE
    ( 2020-11-11) Eleftherakis, George ; Michali ,Maria
    Over the recent years gender equality has been receiving increasing attention, both in accordance to the humanitarian perspective referring to individuals’ welfare and to the Humanitarian-Development Divide (United Nations Sustainable Development Goals – SDGs and UNESCO Priority of Gender Equality), as well as in accordance to enhancing female representation in fields ‘traditionally’ encountered as male-dominated, namely the STEM-related disciplines. In relation to STEM, the gender gap is prominent in various fields −for instance in research and in academia─, and in Science and Technology occupations. According to She Figures 2018, Europe may be close to bridging the gender gap in the doctoral field (47,9% female doctoral students in 2016), but there are considerable differences in gender representation per field of expertise; females constitute less than 1/3 in STEM fields such as Information and Communication Technologies (ICT) and Engineering-Manufacturing-Construction (21% and 29% in 2016 accordingly). A lack of diversity exists in the labour market as well, with only 30% of women with STEM qualifications in Europe having a relevant occupation; in other words, “a significant number of them take jobs in-non related roles, representing a loss of talent and potential and economic gains” (Salinas and Bagni, 2017, p. 721). Nevertheless, female inclusion in STEM does not rely only in augmenting female representation in terms of statistical percentages. Women face other prominent problems, like formal and informal recruitment-selection procedures hindering their advancement in science and especially in polytechnic careers (Carvalho and Santiago, 2010), while gender representations, ‘extra-organisational’ gender roles (Mills, 1988), or role models that encourage or discourage females from engaging in STEM are issues beginning to be addressed. Within the context of our study, gender (in)equality and related multi-layered interventions (i.e. not only referring to a higher numerical representation of women) are addressed in relation to STEM disciplines. These interventions are interrelated to some SDGs sub-objectives, to the European Commission’s ‘commands’ for gender equality in the European Research Area (ERA), as well as to the concept of Responsible Research and Innovation (RRI). Firstly, Goal 5.B of the SDGs suggests to enhance the use of enabling technology and ICT to promote female empowerment, while the European Commission (EC) similarly introduces gender equality policy interventions in scientific fields and calls for action towards a proper integration of gender issues through specific proposals in EU Research&Innovation Programmes, namely Horizon Europe and Horizon 2020 (European Commission, 2014). This is the focal point where these European initiatives are complemented by RRI. RRI refers to tackling contemporary societal challenges by aligning the values, needs and expectations of all actors involved in R&I systems. In the view of Von Schomberg (as cited in Owen et al, 2012) and his definition of RRI, “science and innovation are envisaged as being directed at, and undertaken towards, socially desirable and socially acceptable ends, through an inclusive and deliberative process” (p.753). These socially desirable ends actually seem to have been transformed to the six policy agendas that RRI addresses; the six RRI keys. Gender equality also belongs to these keys, and acquires multiple layers within RRI (depicted in Figure 1, which was designed according to the input from RRI tools website). Figure 1.RRI and Gender Equality Promoting gender-balanced research teams Breaking down gender stereotypes Ensuring gender-friendly workplace cultures Raising awareness towards gender-sensitive investment and funding Gender balance in decision-making Considering the gender dimension in R&I Gender Equality within RRI Source: RRI tools website Currently, several RRI initiatives foster female inclusion in STEM disciplines, and are related to projects implemented mainly during Framework Programme 7 (FP7) and Horizon 2020 (H2020). These projects set gender equality as a priority in various Research Performing Organisations (RPOs) with a STEM expertise, and proceed to the development of self-tailored Gender Equality Plans (GEPs). The GEPs aim to institutionalise gender equality, trigger structural transformations in the RPOs and reach a broad knowledge transfer which contributes to meeting various ERA objectives (e.g. priority 4). In a similar line of argument, the present study delves deeper into RRI initiatives towards gender equality, and examines FP7 and H2020 EU funded projects that foster gender diversity and female inclusion in STEM-related RPOs. Emphasis is on the RRI key of gender equality as opposed to the other keys, since it constitutes an emerging issue reflecting contemporary concerns. It is actually a multifaceted issue, as gender equality is not just a number problem and complementary activities should be implemented for ‘changing’ the scientific status quo. The aim of this study, therefore, is to critically analyse the innovation practices implemented within EU Gender Equality projects. While examining various RRI projects (approximately 80) included in the two major calls of FP7 and H2020, five Gender Equality projects have been selected through a two-stage selection procedure including criteria like innovativeness, stake, transparency and impact, and these projects have been further and more critically analysed: EQUAL-IST, STAGES, GENERA, GEECCO and PLOTINA. The subsequent aim is to identify tendencies (‘mega trends’) in the actions of European RPOs, when ameliorating their intimate mechanisms by developing new structures ensuring gender equality. It is worth highlighting that these projects have been considered as a source (a ‘container’ of practices) and the practices as the units of a qualitative analysis. Following the arguments of Braun et al and their six-step framework for conducting a qualitative analysis (2019), we refer to a reflexive thematic analysis of the data collected with an inductive orientation; the processes of coding and theme development have taken place by employing the NVivo software (Version 12; QSR International Pty Ltd, 2018) and the codes/themes developed have been directed by the content of the data. Patterns and regularities were afterwards identified for reaching certain conclusions. Finally, the thematic analysis has been clustered with an essentialist framework (Braun et al, 2019), where one can report an assumed reality evident in the data; the trends/tendencies detected are an assumed reality evident within the practices promoting gender equality in the scientific field. Ultimately, this study investigates promising interventions towards gender imbalance in STEM fields –as it has also been suggested by Gorvacheva et al (2019) in terms of future research in the corresponding topic− and thus functions as a ‘mapping’ tool depicting the European conditions and endorsing the successful RRI practices for ‘gendering’1 the STEM disciplines. However, it has a twofold contribution; it additionally draws valuable conclusions that resemble a set of suggestions and can be employed as such, for aiding STEM-related European actors in genuinely establishing gender equality in R&I processes. In a few words, these conclusions/suggestions, being based on the patterns detected, refer to the contextualization of RRI and the need to develop self-tailored GEPs, to the most common lines of intervention of the GEPs –namely encouraging female leadership in science, measures against horizontal segregation, (early) career development, work-life balance, training towards gender issues and gender-neutral communication, gendering scientific contents and methods etc.− as well as to co-creation processes that accompany the GEPs (e.g. collaborative platforms). Reference is also made to the impact (both internal and external) of the GEPs, and to whether it can contribute to restoring the principles of universalism and meritocracy in scientific ethos. Therefore, the above process −if encountered holistically− can lead to organisations and STEM-related disciplines that are aligned to contemporary societal concerns, and are truly response-able (i.e. able to provide responses to emerging situations and challenges) through innovation and re-search (i.e. continuous search). Of equal importance is that the new emerging definitions of smart societies can be enhanced; smart societies should not just embrace technology but also tackle societal ills (Haupt, 2017) in the way these are represented within the SDGs −and as mentioned gender equality is included in these goals. Finally, smart societies need a paradigmatic shift, while the term ‘paradigm’ refers to the common techniques and values that members of a scientific community share (Kuhn, 1962; Agamben, 2009), and the definition of the paradigmatic shift connotes a fundamental change in the basic concepts and experimental practices of a scientific discipline (Kuhn, 1962). Thus, gender-related practices within STEM disciplines shall replace the basic concept of males dominating this field and genuinely bring this shift, which actually refers to socially desirable ends and behaviors.
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    “Bridging the Gender Gap in STEM Disciplines: An RRI Perspective”
    ( 2020-11-11) Eleftherakis, George ; Michali ,Maria
    Over the recent years gender equality has been receiving increasing attention, both in accordance to the humanitarian perspective referring to individuals’ welfare and to the Humanitarian-Development Divide (United Nations Sustainable Development Goals – SDGs and UNESCO Priority of Gender Equality), as well as in accordance to enhancing female representation in fields ‘traditionally’ encountered as male-dominated, namely the STEM-related disciplines. In relation to STEM, the gender gap is prominent in various fields −for instance in research and in academia─, and in Science and Technology occupations. According to She Figures 2018, Europe may be close to bridging the gender gap in the doctoral field (47,9% female doctoral students in 2016), but there are considerable differences in gender representation per field of expertise; females constitute less than 1/3 in STEM fields such as Information and Communication Technologies (ICT) and Engineering-Manufacturing-Construction (21% and 29% in 2016 accordingly). A lack of diversity exists in the labour market as well, with only 30% of women with STEM qualifications in Europe having a relevant occupation; in other words, “a significant number of them take jobs in-non related roles, representing a loss of talent and potential and economic gains” (Salinas and Bagni, 2017, p. 721). Nevertheless, female inclusion in STEM does not rely only in augmenting female representation in terms of statistical percentages. Women face other prominent problems, like formal and informal recruitment-selection procedures hindering their advancement in science and especially in polytechnic careers (Carvalho and Santiago, 2010), while gender representations, ‘extra-organisational’ gender roles (Mills, 1988), or role models that encourage or discourage females from engaging in STEM are issues beginning to be addressed. Within the context of our study, gender (in)equality and related multi-layered interventions (i.e. not only referring to a higher numerical representation of women) are addressed in relation to STEM disciplines. These interventions are interrelated to some SDGs sub-objectives, to the European Commission’s ‘commands’ for gender equality in the European Research Area (ERA), as well as to the concept of Responsible Research and Innovation (RRI). Firstly, Goal 5.B of the SDGs suggests to enhance the use of enabling technology and ICT to promote female empowerment, while the European Commission (EC) similarly introduces gender equality policy interventions in scientific fields and calls for action towards a proper integration of gender issues through specific proposals in EU Research&Innovation Programmes, namely Horizon Europe and Horizon 2020 (European Commission, 2014). This is the focal point where these European initiatives are complemented by RRI. RRI refers to tackling contemporary societal challenges by aligning the values, needs and expectations of all actors involved in R&I systems. In the view of Von Schomberg (as cited in Owen et al, 2012) and his definition of RRI, “science and innovation are envisaged as being directed at, and undertaken towards, socially desirable and socially acceptable ends, through an inclusive and deliberative process” (p.753). These socially desirable ends actually seem to have been transformed to the six policy agendas that RRI addresses; the six RRI keys. Gender equality also belongs to these keys, and acquires multiple layers within RRI (depicted in Figure 1, which was designed according to the input from RRI tools website). Figure 1.RRI and Gender Equality Promoting gender-balanced research teams Breaking down gender stereotypes Ensuring gender-friendly workplace cultures Raising awareness towards gender-sensitive investment and funding Gender balance in decision-making Considering the gender dimension in R&I Gender Equality within RRI Source: RRI tools website Currently, several RRI initiatives foster female inclusion in STEM disciplines, and are related to projects implemented mainly during Framework Programme 7 (FP7) and Horizon 2020 (H2020). These projects set gender equality as a priority in various Research Performing Organisations (RPOs) with a STEM expertise, and proceed to the development of self-tailored Gender Equality Plans (GEPs). The GEPs aim to institutionalise gender equality, trigger structural transformations in the RPOs and reach a broad knowledge transfer which contributes to meeting various ERA objectives (e.g. priority 4). In a similar line of argument, the present study delves deeper into RRI initiatives towards gender equality, and examines FP7 and H2020 EU funded projects that foster gender diversity and female inclusion in STEM-related RPOs. Emphasis is on the RRI key of gender equality as opposed to the other keys, since it constitutes an emerging issue reflecting contemporary concerns. It is actually a multifaceted issue, as gender equality is not just a number problem and complementary activities should be implemented for ‘changing’ the scientific status quo. The aim of this study, therefore, is to critically analyse the innovation practices implemented within EU Gender Equality projects. While examining various RRI projects (approximately 80) included in the two major calls of FP7 and H2020, five Gender Equality projects have been selected through a two-stage selection procedure including criteria like innovativeness, stake, transparency and impact, and these projects have been further and more critically analysed: EQUAL-IST, STAGES, GENERA, GEECCO and PLOTINA. The subsequent aim is to identify tendencies (‘mega trends’) in the actions of European RPOs, when ameliorating their intimate mechanisms by developing new structures ensuring gender equality. It is worth highlighting that these projects have been considered as a source (a ‘container’ of practices) and the practices as the units of a qualitative analysis. Following the arguments of Braun et al and their six-step framework for conducting a qualitative analysis (2019), we refer to a reflexive thematic analysis of the data collected with an inductive orientation; the processes of coding and theme development have taken place by employing the NVivo software (Version 12; QSR International Pty Ltd, 2018) and the codes/themes developed have been directed by the content of the data. Patterns and regularities were afterwards identified for reaching certain conclusions. Finally, the thematic analysis has been clustered with an essentialist framework (Braun et al, 2019), where one can report an assumed reality evident in the data; the trends/tendencies detected are an assumed reality evident within the practices promoting gender equality in the scientific field. Ultimately, this study investigates promising interventions towards gender imbalance in STEM fields –as it has also been suggested by Gorvacheva et al (2019) in terms of future research in the corresponding topic− and thus functions as a ‘mapping’ tool depicting the European conditions and endorsing the successful RRI practices for ‘gendering’1 the STEM disciplines. However, it has a twofold contribution; it additionally draws valuable conclusions that resemble a set of suggestions and can be employed as such, for aiding STEM-related European actors in genuinely establishing gender equality in R&I processes. In a few words, these conclusions/suggestions, being based on the patterns detected, refer to the contextualization of RRI and the need to develop self-tailored GEPs, to the most common lines of intervention of the GEPs –namely encouraging female leadership in science, measures against horizontal segregation, (early) career development, work-life balance, training towards gender issues and gender-neutral communication, gendering scientific contents and methods etc.− as well as to co-creation processes that accompany the GEPs (e.g. collaborative platforms). Reference is also made to the impact (both internal and external) of the GEPs, and to whether it can contribute to restoring the principles of universalism and meritocracy in scientific ethos. Therefore, the above process −if encountered holistically− can lead to organisations and STEM-related disciplines that are aligned to contemporary societal concerns, and are truly response-able (i.e. able to provide responses to emerging situations and challenges) through innovation and re-search (i.e. continuous search). Of equal importance is that the new emerging definitions of smart societies can be enhanced; smart societies should not just embrace technology but also tackle societal ills (Haupt, 2017) in the way these are represented within the SDGs −and as mentioned gender equality is included in these goals. Finally, smart societies need a paradigmatic shift, while the term ‘paradigm’ refers to the common techniques and values that members of a scientific community share (Kuhn, 1962; Agamben, 2009), and the definition of the paradigmatic shift connotes a fundamental change in the basic concepts and experimental practices of a scientific discipline (Kuhn, 1962). Thus, gender-related practices within STEM disciplines shall replace the basic concept of males dominating this field and genuinely bring this shift, which actually refers to socially desirable ends and behaviors.
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    Cloud service brokerage: enhancing resilience in virtual enterprises through service governance and quality assurance
    ( 2017-12) Veloudis, Simeon ; Paraskakis, I. ; Petsos, Christos
    We argue that cloud service brokerage (CSB) mechanisms can strengthen the resilience of services in cloud-based VEs. In this respect, we present the Service Completeness-Compliance Checker (SC$$^3$$3), a mechanism which offers capabilities with respect to the quality assurance dimension of CSB. More specifically, the SC$$^3$$3 strengthens the resilience of cloud services by evaluating their conformance with pre-specified policies concerning the business aspects of their delivery, as well as by managing the evolution of their lifecycle in a controlled and policy-based manner. By relying on an ontology-based representation of policies and services, the SC$$^3$$3 achieves a proper separation of concerns between policy definition and policy enforcement. This effectively enables the SC$$^3$$3 to operate in a manner generic and agnostic to any underlying cloud delivery platform, as well as to reason about the well-formedness of the pre-specified policies.
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    Context-aware Policy Enforcement for PaaS-enabled Access Control
    (IEEE, 2019-07-09) Verginadis, Yannis ; Pationiotakis, Ioannis ; Gouvas, Panagiotis ; Mantzouratos, Spyros ; Schork, Sebastian Thomas ; Veloudis, Simeon ; Seitz, Ludwig ; Paraskakis, Iraklis ; Mentzas, Grigoris
    It is generally conceded that, due to security and privacy concerns, enterprises and users are reluctant to embrace the cloud computing paradigm and hence benefit from the cost reductions and the increased flexibility or business agility that this paradigm brings about. These concerns stem mainly from the significantly-expanded attack surfaces that result from the heterogeneous nature of cloud services and the dynamicity inherent in cloud environments. In order to alleviate these concerns, effective and flexible access control approaches are required to consider the contextual parameters that characterise data access requests in the cloud. In this respect, this work presents PaaSword: a novel holistic access control framework—essentially a PaaS offering—that extends the popular XACML standard with semantic reasoning capabilities that support the federation of effective context-aware access control policies and their infusion into cloud applications with minimal manual intervention and effort. To determine the performance of our solution, a comparative evaluation test is presented and discussed, against a well-known reference implementation of the XACML standard, namely the open source WSO2 Balana engine.
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    Context-aware Security Models for PaaS-enabled Access Control
    ( 2016-04) Veloudis, Simeon ; Verginadis, Yannis ; Pationiotakis, Ioannis ; Paraskakis, Iraklis ; Mentzas, Grigoris
    Enterprises are embracing cloud computing in order to reduce costs and increase agility in their everyday business operations. Nevertheless, due mainly to confidentiality, privacy and integrity concerns, many are still reluctant to migrate their sensitive data to the cloud. In this paper, firstly, we outline the construction of a suitable Context-aware Security Model, for enhancing security in cloud applications. Secondly, we outline the construction of an extensible and declarative formalism for representing policy-related knowledge, one which disentangles the definition of a policy from the code employed for enforcing it. Both of them will be employed for supporting innovative PaaS-enabled access control mechanisms.
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    Foundations for Designing, Defining, Validating and Executing Access Control Policies in Cloud Environments
    ( 2017-09) Veloudis, Simeon ; Paraskakis, I. ; Petsos, Christos
    By embracing cloud computing enterprises are able to boost their agility and productivity whilst realising significant cost savings. However, due to security and privacy concerns, many enterprises are reluctant to migrate their data and operations to the cloud. One way to alleviate these concerns is to devise access control policies that infuse suitable security controls into cloud services. Nevertheless, the complexity inherent in such policies, stemming from the dynamic nature of cloud environments, calls for a framework that provides assurances with respect to the effectiveness of the policies. In this respect, this work proposes a class of constraints, the so-called well-formedness constraints, that provide such assurances by empowering stakeholders to harness the attributes of the policies. Both the policies and the constraints are expressed ontologically hence enabling automated reasoning about the abidance of the policies with the constraints.
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    Modelling argumentation in short text: A case of social media debate
    ( 2021-11) Lytos, Anastasios ; Lagkas, Thomas ; Sarigiannidis, Panagiotis ; Argyriou, Vasileios ; Eleftherakis, George
    The technological leaps of artificial intelligence (AI) and the rise of machine learning have triggered significant progress in a plethora of natural language processing (NLP) and natural language understanding tasks. One of these tasks is argumentation mining which has received significant interest in recent years and is regarded as a key domain for future decision-making systems, behaviour modelling, and natural language understanding problems. Until recently, natural language modelling tasks, such as computational argumentation schemes, were often tested in controlled environments, such as persuasive essays, reducing unexpected behaviours that could occur in real-life settings, like a public debate on social media. Additionally, the growing demand for enhancing the trust and the explainability of the AI services has dictated the design and adoption of modelling schemes to increase the confidence in the outcomes of the AI solutions. This paper attempts to explore modelling argumentation in short text and proposes a novel framework for argumentation detection under the name Abstract Framework for Argumentation Detection (AFAD). Moreover, different proof-of-concept implementations are provided to examine the applicability of the proposed framework to very short text developing a rule-based mechanism and compare the results with data-driven solutions. Eventually, a combination of the deployed methods is applied increasing the correct predictions in the minority class on an imbalanced dataset. The findings suggest that the modelling process provides solid grounds for technical research while the hybrid solutions have the potential to be applied to a wide range of NLP-related tasks offering a deeper understanding of human language and reasoning.
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    Modelling argumentation in short text: A case of social media debate
    (Elsevier, 2022-02) Lytos, Anastasios ; Lagkas, Thomas ; Argyriou, Vasileios ; Eleftherakis, George
    The technological leaps of artificial intelligence (AI) and the rise of machine learning have triggered significant progress in a plethora of natural language processing (NLP) and natural language understanding tasks. One of these tasks is argumentation mining which has received significant interest in recent years and is regarded as a key domain for future decision-making systems, behaviour modelling, and natural language understanding problems. Until recently, natural language modelling tasks, such as computational argumentation schemes, were often tested in controlled environments, such as persuasive essays, reducing unexpected behaviours that could occur in real-life settings, like a public debate on social media. Additionally, the growing demand for enhancing the trust and the explainability of the AI services has dictated the design and adoption of modelling schemes to increase the confidence in the outcomes of the AI solutions. This paper attempts to explore modelling argumentation in short text and proposes a novel framework for argumentation detection under the name Abstract Framework for Argumentation Detection (AFAD). Moreover, different proof-of-concept implementations are provided to examine the applicability of the proposed framework to very short text developing a rule-based mechanism and compare the results with data-driven solutions. Eventually, a combination of the deployed methods is applied increasing the correct predictions in the minority class on an imbalanced dataset. The findings suggest that the modelling process provides solid grounds for technical research while the hybrid solutions have the potential to be applied to a wide range of NLP-related tasks offering a deeper understanding of human language and reasoning.
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    NebulOuS: A Meta-Operating System with Cloud Continuum Brokerage Capabilities
    (Zenodo, 2023-09-14) Verginadis, Yannis ; Sarros, Christos-Alexandros ; Reyes de Los Mozos, Mario ; Veloudis, Simeon ; Piliszek,Radosław ; Kourtellis, Nicolas ; Horn, Geir
    Cloud Continuum is the paradigm that unifies and exploits resources from far edge to public and private cloud offerings, as well as processing nodes with significant capacity in between. Nowadays, the combination of all these resources for augmenting modern hyper-distributed applications becomes a necessity, especially considering the vast volumes of data, their velocity, and their variety, which constitute well known challenges of Big Data processing. In this paper, we address the main research question on how a Cloud Continuum management platform should be structured to cope with the constantly increasing challenges and opportunities of the domain. We introduce the NebulOuS architecture vision towards accomplishing substantial research contributions in the realms of Cloud Continuum brokerage. We propose an advanced architecture that enables secure and optimal application provisioning, as well as reconfiguration over the Cloud Continuum. NebulOuS introduces a novel Meta- Operating System and platform, that is currently being developed, for enabling transient Cloud Continuum brokerage ecosystems that seamlessly exploit edge and fog nodes, in conjunction with multi-cloud resources, to cope with the requirements posed by low latency applications.
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    Ontological Definition of Governance Framework for Security Policies in Cloud Environments
    ( 2017-09) Veloudis, Simeon ; Paraskakis, I. ; Petsos, Christos
    The cloud computing paradigm enables enterprises to realise sig- nificant cost savings whilst boosting their agility and productivity. However, security and privacy concerns generally deter enterprises from migrating their critical data to the cloud. One way to alleviate these concerns, hence bolster the adoption of cloud computing, is to devise adequate security policies that control the manner in which these data are stored and accessed in the cloud. Nevertheless, for enterprises to entrust these policies, a framework capable of providing assurances about their correctness is required. This work proposes such a framework. In particular, it proposes an approach that enables enterprises to define their own view of what consti- tutes a correct policy through the formulation of an appropriate set of well-formedness constraints. These constraints are expressed ontologically thus enabling—by virtue of semantic inferencing— automated reasoning about their satisfaction by the policies
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    Ontological Framework for Ensuring Correctness of Security Policies in Cloud Environments
    ( 2017-09) Veloudis, Simeon ; Paraskakis, I. ; Petsos, Christos
    By embracing the cloud computing paradigm enterprises are able to boost their agility and productivity whilst realising significant cost savings. However, many enterprises are reluctant to adopt cloud services for supporting their critical operations due to security and privacy concerns. One way to alleviate these concerns is to devise policies that infuse suitable security controls in cloud services. This work proposes a class of ontologically-expressed rules, namely the so-called axiomatic rules, that aim at ensuring the correctness of these policies by harnessing the various knowledge artefacts that they embody. It also articulates an adequate framework for the expression of policies, one which provides ontological templates for modelling the knowledge artefacts encoded in the policies and which form the basis for the proposed axiomatic rules.
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    Ontological Templates for Regulating Access to Sensitive Medical Data in the Cloud
    ( 2017-06) Veloudis, Simeon ; Paraskakis, Iraklis ; Verginadis, Yannis ; Pationiotakis, Ioannis ; Mentzas, Grigoris
    By embracing the cloud computing paradigm for storing and processing electronic medical records (EMRs), modern healthcare providers are able to realise significant cost savings. However, relinquishing control of sensitive medical data by delegating their storage and processing to third-party cloud providers naturally raises significant security concerns. One way to alleviate these concerns is to devise appropriate policies that infuse adequate access controls in cloud services. Nevertheless, the heterogeneous nature of these services, coupled with the dynamicity inherent in cloud environments, hinder the formulation of effective and interoperable policies that are appropriate for the underlying domain of application. To this end, this work adopts the ontological templates proposed in [5] for the representation of access control policies in the medical sector. By capturing the knowledge that must be infused into an access control policy, these templates sufficiently address the needs of the underlying domain of application in which such a policy is to be enforced; at the same time, they facilitate developers in infusing adequate access controls to their cloud applications.
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    Policy Management and Enforcement Using OWL and SWRL for the Internet of Things
    ( 2017-09) Dautov, Rustem ; Veloudis, Simeon ; Paraskakis, Iraklis
    As the number of connected devices is exponentially grow- ing, the IoT community is investigating potential ways of overcoming the resulting heterogeneity to enable device compatibility, interoperabil- ity and integration. The Semantic Web technologies, frequently used to address these issues, have been employed to develop a number of ontolog- ical frameworks, aiming to provide a common vocabulary of terms for the IoT domain. Defined in Web Ontology Language – a language based on the Description Logics, and thus equipped with the ‘off-the-shelf’ sup- port for formal reasoning – these ontologies, however, seem to neglect the built-in automated reasoning capabilities. Accordingly, this paper discusses the possibility of leveraging this idle potential for automated analysis in the context of defining and enforcing policies for the IoT. As a first step towards a proof of concept, the paper focuses on a simple use case and, using the existing IoT-Lite ontology, demonstrates different types of semantic classification to enable policy enforcement. As a result, it becomes possible to detect a critical situation, when a dangerous tem- perature threshold has been exceeded. With the proposed approach, IoT practitioners are offered an already existing, reliable and optimised pol- icy enforcement mechanism. Moreover, they are also expected to benefit from support for policy governance, separation of concerns, a declarative approach to knowledge engineering, and an extensible architecture.