Domenico Rosaci | Mediterranean University of Reggio Calabria (original) (raw)
Papers by Domenico Rosaci
Future Generation Computer Systems, Jul 1, 2020
Smart cities are built on top of heterogeneous IoT infrastructures, that can be viewed as communi... more Smart cities are built on top of heterogeneous IoT infrastructures, that can be viewed as communities of software agents (the intelligent objects) that interact with each other to realize complex activities. These agents operate on behalf of users that need services; for these reason agents are often in competition with each other. On the other hand, an agent can often benefit from collaborating with other agents in some circumstances, exchanging information and services. Under this viewpoint, the task of finding the best partners to collaborate is a key task for an agent. A general consensus exists about the benefits deriving by forming friendships and groups for mutual cooperation inside competitive Multi-Agent Systems (MASs). In this respect, the existing proposals are usually addressed to maximize the profit at the level of individual agent or group. Unfortunately, the most part of these approaches could advantage the most aggressive agents, also in presence of bad social behaviors. This is not a desired scenario in a smart city environment. A possible solution to this problem is that of promoting correct behaviors and meritocracy inside agent communities. To this aim, we propose to model the competitive MAS scenario in the framework of non cooperative games by assuming to represent (i) the trustworthiness of agents relationships by means of a trust model and (ii) the capability of a community to provide its members with a good environment by means of its social capital. As a result, a group formation algorithm capable to asymptotically maximize the social capital is proposed. This algorithm highlights two main features: (i) the computed solution is a Nash equilibrium in the considered game and (ii) the only rewarded agents are those having the most correct behaviors.
Studies in computational intelligence, 2018
The need of managing complex and interactive activities is becoming a key challenge in the “Inter... more The need of managing complex and interactive activities is becoming a key challenge in the “Internet of Things” (IoT) and leads to request large hardware and power resources. A possibility of facing such a problem is represented by the possibility of virtualizing physical IoT environments over the so called Cloud-of-Things (CoT), where each device is associated with one or more software agents working in the Cloud on its behalf. In this open and heterogeneous context, IoT devices obtain significant advantages by the social cooperation of software agents, and the selection of the most trustworthy partners for cooperating becomes a crucial issue, making necessary to use a suitable trust model. The cooperation activity can be further improved by clustering agents in different groups on the basis of trust measures, allowing each agent will to interact with the agents belonging to its own group. To this purpose, we designed an algorithm to form agent groups on the basis of information about reliability and reputation collected by the agents. In order to validate both the efficiency and effectiveness of our approach, we performed some experiments in a simulated scenario, which showed significant advantages introduces by the use of the trust measures.
Simulation Modelling Practice and Theory, Apr 1, 2021
In an agent-based cloud scenario, when two agents, provided with different ontologies exchange me... more In an agent-based cloud scenario, when two agents, provided with different ontologies exchange messages to negotiate a Service Level Agreement for a cloud service, they could fail to understand both the correct meaning of their messages and the offered service quality, due to the differences present in their ontologies. In all these cases, a semantic negotiation is required to reciprocally making understandable the messages exchanged about the cloud service characteristics. In this work we propose a protocol for supporting the SLA negotiation process, involving semantic issues, which do not require the use of a common global agent ontology sharing knowledge in advance. In detail, this protocol considers that each agent is able to partition the other agents based on both their expertise in cloud services and similarity with their own ontologies.
Springer eBooks, 2013
The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein.
The Computer Journal, Aug 22, 2017
This paper proposes a trust model for a competitive federation of Cloud computing systems. The re... more This paper proposes a trust model for a competitive federation of Cloud computing systems. The reference scenario is a large-scale environment in which different Cloud providers compete in offering their pay-per-use XaaS (Anything as a Service) resources to the various users. In this context, to obtain the assignment of a user request, providers may state to possess more resources than the amount really available: the result could be the provisioning of a services with a lower QoS than expected. A trust model is thus mandatory to help the requester to properly choose the adequate provider on the basis of (i) the reliability shown in the past in providing services, and (ii) the reputation the provider has to other users. In this sense, the paper presents an extension to the RRAF model, which has been suitably adapted to a large-scale environment by means of the introduction of a multi-dimensional approach which fits the various reliability issues, typical of Cloud computing systems.
Springer eBooks, Nov 10, 2022
Information Systems, Nov 1, 2018
An important issue in Online Social Networks consists of the capability to generate useful recomm... more An important issue in Online Social Networks consists of the capability to generate useful recommendations for users, as peers to contact in order to establish friendships and collaborations, interesting resources to use and so on. This implies the necessity of evaluating the trustworthiness a user should
IEEE Transactions on Computational Social Systems, 2022
WOA, 2017
In social communities the composition of thematic groups varies over time due to changes occurrin... more In social communities the composition of thematic groups varies over time due to changes occurring in users' behaviors. To study the time evolution of such a process, we design a conceptual framework exploiting a distributed algorithm driving group formation. The results of tests carried out on real data extracted by the social network CIAO, show as groups formed by combining similarity and trust measures are i) more time-stable, independently by the weight of the trust component, and ii) more time-homogeneous, independently by the presence of uncorrelated random agents' behaviors affecting the similarity component.
Studies in computational intelligence, 2023
Studies in computational intelligence, 2022
Springer eBooks, 2015
Social Sciences identify similarity and mutual trust as main criteria to consider in group format... more Social Sciences identify similarity and mutual trust as main criteria to consider in group formation processes. On this basis, we present a group formation technique which exploits measures of both similarity and trust, in order to improve the compactness of groups in Online Social Networks. Similarity and trust have been jointly exploited to design two algorithms designed to match groups and users, in order to capture the gain of a user who desires to join with a group and the benefit of the group itself. Experimental results show that trust is more valuable than similarity in forming groups and that the two proposed algorithms are capable to deal with large networks.
Studies in computational intelligence, 2022
Computers & Electrical Engineering, Dec 1, 2021
In competitive Multi-Agent Systems (MASs) for IoT, an important task is to form friendships and g... more In competitive Multi-Agent Systems (MASs) for IoT, an important task is to form friendships and groups for mutual cooperation. The existing proposals try to improve the profit of individual agent or group but, on the other hand, the most aggressive agents may take advantages from these approaches by means of malicious behaviors. In this work we model a MAS framework of non cooperative games by taking into account i) the reliability of agents relationships through a trust model and ii) the community ability to furnish a good environment to its members through its social capital. Thus, we designed an algorithm that maximizes the social capital. We emphasize two main findings: i) the result is a Nash equilibrium and ii) the agents are awarded only if they behave correctly.
2019 6th International Conference on Control, Decision and Information Technologies (CoDIT)
The “Internet of Things” (IoT) is requiring increasing computational capabilities which can be ob... more The “Internet of Things” (IoT) is requiring increasing computational capabilities which can be obtained from Machine-to-Machine cooperation among smart objects. The convergence of IoT and Multi-Agent Systems gives the opportunity to benefit of their social attitude to interact and cooperate for services. In a mobile and federated context, selecting reliable partners for cooperation is a complex task because the most part of devices are not referenced with respect to their trustworthiness. The aggregation of agents in groups, in each IoT environment, on the basis of reputation information can provide a solution to this problem. In order to spread device/agent reputation information in our distributed scenario without using a central repository, we propose to rely on the blockchain technology to support a reputation approach to form groups. In particular, information about the reputation capital, certified by the blockchain, is used by an algorithm to drive group formation processes of agents in IoT environments.
IEEE/CAA Journal of Automatica Sinica, 2020
In this paper, we are interested in answering the following research question: “ Is it possible t... more In this paper, we are interested in answering the following research question: “ Is it possible to form effective groups in virtual communities by exploiting trust information without significant overhead, similarly to real user communities? ” In order to answer this question, instead of adopting the largely used approach of exploiting the opinions provided by all the users of the community ( called global reputation ) , we propose to use a particular form of reputation, called local reputation. We also propose an algorithm for group formation able to implement the proposed procedure to form effective groups in virtual communities. Another interesting question is how to measure the effectiveness of groups in virtual communities. To this aim we introduce the Gk index in a measure of the effectiveness of the group formation. We tested our algorithm by realizing some experimental trials on real data from the real world EPINIONS and CIAO communities, showing the significant advantages of our procedure w.r.t. another prominent approach based on traditional global reputation.
Future Generation Computer Systems, Jul 1, 2020
Smart cities are built on top of heterogeneous IoT infrastructures, that can be viewed as communi... more Smart cities are built on top of heterogeneous IoT infrastructures, that can be viewed as communities of software agents (the intelligent objects) that interact with each other to realize complex activities. These agents operate on behalf of users that need services; for these reason agents are often in competition with each other. On the other hand, an agent can often benefit from collaborating with other agents in some circumstances, exchanging information and services. Under this viewpoint, the task of finding the best partners to collaborate is a key task for an agent. A general consensus exists about the benefits deriving by forming friendships and groups for mutual cooperation inside competitive Multi-Agent Systems (MASs). In this respect, the existing proposals are usually addressed to maximize the profit at the level of individual agent or group. Unfortunately, the most part of these approaches could advantage the most aggressive agents, also in presence of bad social behaviors. This is not a desired scenario in a smart city environment. A possible solution to this problem is that of promoting correct behaviors and meritocracy inside agent communities. To this aim, we propose to model the competitive MAS scenario in the framework of non cooperative games by assuming to represent (i) the trustworthiness of agents relationships by means of a trust model and (ii) the capability of a community to provide its members with a good environment by means of its social capital. As a result, a group formation algorithm capable to asymptotically maximize the social capital is proposed. This algorithm highlights two main features: (i) the computed solution is a Nash equilibrium in the considered game and (ii) the only rewarded agents are those having the most correct behaviors.
Studies in computational intelligence, 2018
The need of managing complex and interactive activities is becoming a key challenge in the “Inter... more The need of managing complex and interactive activities is becoming a key challenge in the “Internet of Things” (IoT) and leads to request large hardware and power resources. A possibility of facing such a problem is represented by the possibility of virtualizing physical IoT environments over the so called Cloud-of-Things (CoT), where each device is associated with one or more software agents working in the Cloud on its behalf. In this open and heterogeneous context, IoT devices obtain significant advantages by the social cooperation of software agents, and the selection of the most trustworthy partners for cooperating becomes a crucial issue, making necessary to use a suitable trust model. The cooperation activity can be further improved by clustering agents in different groups on the basis of trust measures, allowing each agent will to interact with the agents belonging to its own group. To this purpose, we designed an algorithm to form agent groups on the basis of information about reliability and reputation collected by the agents. In order to validate both the efficiency and effectiveness of our approach, we performed some experiments in a simulated scenario, which showed significant advantages introduces by the use of the trust measures.
Simulation Modelling Practice and Theory, Apr 1, 2021
In an agent-based cloud scenario, when two agents, provided with different ontologies exchange me... more In an agent-based cloud scenario, when two agents, provided with different ontologies exchange messages to negotiate a Service Level Agreement for a cloud service, they could fail to understand both the correct meaning of their messages and the offered service quality, due to the differences present in their ontologies. In all these cases, a semantic negotiation is required to reciprocally making understandable the messages exchanged about the cloud service characteristics. In this work we propose a protocol for supporting the SLA negotiation process, involving semantic issues, which do not require the use of a common global agent ontology sharing knowledge in advance. In detail, this protocol considers that each agent is able to partition the other agents based on both their expertise in cloud services and similarity with their own ontologies.
Springer eBooks, 2013
The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein.
The Computer Journal, Aug 22, 2017
This paper proposes a trust model for a competitive federation of Cloud computing systems. The re... more This paper proposes a trust model for a competitive federation of Cloud computing systems. The reference scenario is a large-scale environment in which different Cloud providers compete in offering their pay-per-use XaaS (Anything as a Service) resources to the various users. In this context, to obtain the assignment of a user request, providers may state to possess more resources than the amount really available: the result could be the provisioning of a services with a lower QoS than expected. A trust model is thus mandatory to help the requester to properly choose the adequate provider on the basis of (i) the reliability shown in the past in providing services, and (ii) the reputation the provider has to other users. In this sense, the paper presents an extension to the RRAF model, which has been suitably adapted to a large-scale environment by means of the introduction of a multi-dimensional approach which fits the various reliability issues, typical of Cloud computing systems.
Springer eBooks, Nov 10, 2022
Information Systems, Nov 1, 2018
An important issue in Online Social Networks consists of the capability to generate useful recomm... more An important issue in Online Social Networks consists of the capability to generate useful recommendations for users, as peers to contact in order to establish friendships and collaborations, interesting resources to use and so on. This implies the necessity of evaluating the trustworthiness a user should
IEEE Transactions on Computational Social Systems, 2022
WOA, 2017
In social communities the composition of thematic groups varies over time due to changes occurrin... more In social communities the composition of thematic groups varies over time due to changes occurring in users' behaviors. To study the time evolution of such a process, we design a conceptual framework exploiting a distributed algorithm driving group formation. The results of tests carried out on real data extracted by the social network CIAO, show as groups formed by combining similarity and trust measures are i) more time-stable, independently by the weight of the trust component, and ii) more time-homogeneous, independently by the presence of uncorrelated random agents' behaviors affecting the similarity component.
Studies in computational intelligence, 2023
Studies in computational intelligence, 2022
Springer eBooks, 2015
Social Sciences identify similarity and mutual trust as main criteria to consider in group format... more Social Sciences identify similarity and mutual trust as main criteria to consider in group formation processes. On this basis, we present a group formation technique which exploits measures of both similarity and trust, in order to improve the compactness of groups in Online Social Networks. Similarity and trust have been jointly exploited to design two algorithms designed to match groups and users, in order to capture the gain of a user who desires to join with a group and the benefit of the group itself. Experimental results show that trust is more valuable than similarity in forming groups and that the two proposed algorithms are capable to deal with large networks.
Studies in computational intelligence, 2022
Computers & Electrical Engineering, Dec 1, 2021
In competitive Multi-Agent Systems (MASs) for IoT, an important task is to form friendships and g... more In competitive Multi-Agent Systems (MASs) for IoT, an important task is to form friendships and groups for mutual cooperation. The existing proposals try to improve the profit of individual agent or group but, on the other hand, the most aggressive agents may take advantages from these approaches by means of malicious behaviors. In this work we model a MAS framework of non cooperative games by taking into account i) the reliability of agents relationships through a trust model and ii) the community ability to furnish a good environment to its members through its social capital. Thus, we designed an algorithm that maximizes the social capital. We emphasize two main findings: i) the result is a Nash equilibrium and ii) the agents are awarded only if they behave correctly.
2019 6th International Conference on Control, Decision and Information Technologies (CoDIT)
The “Internet of Things” (IoT) is requiring increasing computational capabilities which can be ob... more The “Internet of Things” (IoT) is requiring increasing computational capabilities which can be obtained from Machine-to-Machine cooperation among smart objects. The convergence of IoT and Multi-Agent Systems gives the opportunity to benefit of their social attitude to interact and cooperate for services. In a mobile and federated context, selecting reliable partners for cooperation is a complex task because the most part of devices are not referenced with respect to their trustworthiness. The aggregation of agents in groups, in each IoT environment, on the basis of reputation information can provide a solution to this problem. In order to spread device/agent reputation information in our distributed scenario without using a central repository, we propose to rely on the blockchain technology to support a reputation approach to form groups. In particular, information about the reputation capital, certified by the blockchain, is used by an algorithm to drive group formation processes of agents in IoT environments.
IEEE/CAA Journal of Automatica Sinica, 2020
In this paper, we are interested in answering the following research question: “ Is it possible t... more In this paper, we are interested in answering the following research question: “ Is it possible to form effective groups in virtual communities by exploiting trust information without significant overhead, similarly to real user communities? ” In order to answer this question, instead of adopting the largely used approach of exploiting the opinions provided by all the users of the community ( called global reputation ) , we propose to use a particular form of reputation, called local reputation. We also propose an algorithm for group formation able to implement the proposed procedure to form effective groups in virtual communities. Another interesting question is how to measure the effectiveness of groups in virtual communities. To this aim we introduce the Gk index in a measure of the effectiveness of the group formation. We tested our algorithm by realizing some experimental trials on real data from the real world EPINIONS and CIAO communities, showing the significant advantages of our procedure w.r.t. another prominent approach based on traditional global reputation.