Dr. Mozhgan Tavakolifard

The importance of trust in electronic transactions is well understood. The majority of current
trust models consist of a central entity that verifies compliance with the trust requirements,
using standardized evaluation methods and criteria. In decentralized environments, the
communication scenarios are more complex, and no universally accepted objective
requirements or evaluation criteria exist. It should be noted that the situation would get even
more complicated when… Vis mer

The importance of trust in electronic transactions is well understood. The majority of current
trust models consist of a central entity that verifies compliance with the trust requirements,
using standardized evaluation methods and criteria. In decentralized environments, the
communication scenarios are more complex, and no universally accepted objective
requirements or evaluation criteria exist. It should be noted that the situation would get even
more complicated when agents are interacting with each other. The goal of this research ... Vis mindre

During the past decade, online trust and reputation systems have provided cogent
answers to emerging challenges in the global computing infrastructures relating to computer
and network security, electronic commerce, virtual enterprises, social networks and cloud
computing. The goal of these systems in such global computing infrastructures is to allow
entities to reason about the trustworthiness of other entities and to make autonomous
decisions on the basis of trust. This… Vis mer

During the past decade, online trust and reputation systems have provided cogent
answers to emerging challenges in the global computing infrastructures relating to computer
and network security, electronic commerce, virtual enterprises, social networks and cloud
computing. The goal of these systems in such global computing infrastructures is to allow
entities to reason about the trustworthiness of other entities and to make autonomous
decisions on the basis of trust. This requires the development of computational trust ... Vis mindre

Trust is situation-specific and the trust judgment problem with which the truster is
confronted might be, in some ways, similar but not identical to some problems the truster has
previously encountered. The truster then may draw information from these past experiences
useful for the current situation. We present a knowledge-intensive and model-based case-
based reasoning framework that supports the truster to infer such information. The
suggested method augments the typically… Vis mer

Trust is situation-specific and the trust judgment problem with which the truster is
confronted might be, in some ways, similar but not identical to some problems the truster has
previously encountered. The truster then may draw information from these past experiences
useful for the current situation. We present a knowledge-intensive and model-based case-
based reasoning framework that supports the truster to infer such information. The
suggested method augments the typically sparse trust information by inferring the missing ... Vis mindre

This paper proposes a rule-based reasoner system that adjusts the ratings based
on the underlying siltation, thus, imposes situation awareness to the existing trust models.
Furthermore, it helps the trust model to bootstrap by providing an estimation of trust value
based on similar situations or similar trustees previously observed. The rules are
automatically extracted from the history and encoded as conditions connecting contextual
information to trust judgments. Through… Vis mer

This paper proposes a rule-based reasoner system that adjusts the ratings based
on the underlying siltation, thus, imposes situation awareness to the existing trust models.
Furthermore, it helps the trust model to bootstrap by providing an estimation of trust value
based on similar situations or similar trustees previously observed. The rules are
automatically extracted from the history and encoded as conditions connecting contextual
information to trust judgments. Through the use of subjective logic, this method explicitly ... Vis mindre

The Internet is a perfectly distributed and uncontrolled medium. However, the use
of this technology to its utmost boundaries requires robust and efficient trust mechanisms.
This paper describes a context-sensitive trust management system, in which a rule-based
reasoner is used to assess the trustability of the trustee on the basis of available historical
information. The rules are automatically extracted from the history and encoded as
conditions connecting contextual… Vis mer

The Internet is a perfectly distributed and uncontrolled medium. However, the use
of this technology to its utmost boundaries requires robust and efficient trust mechanisms.
This paper describes a context-sensitive trust management system, in which a rule-based
reasoner is used to assess the trustability of the trustee on the basis of available historical
information. The rules are automatically extracted from the history and encoded as
conditions connecting contextual information to trust judgments. Through the use of ... Vis mindre

We propose an ontology-based approach for inferences linking trust information in
two different situations. That reasoning process can augment the typically sparse trust
information, by inferring the missing information from other situational conditions, and can
better support situation-aware trust management. Our work is more comprehensive in
comparison with other models and considers various aspects of the relationship between
situation-awareness and trust management.

Social recommender systems aim to alleviate the information overload problem on
social network sites. The social network structure is often an important input to these
recommender systems. Typically, this structure cannot be inferred directly from declared
relationships among users. The goal of our work is to extract an underlying hidden and
sparse network which more strongly represents the actual interactions among users. We
study how to leverage Twitter activities like… Vis mer

Social recommender systems aim to alleviate the information overload problem on
social network sites. The social network structure is often an important input to these
recommender systems. Typically, this structure cannot be inferred directly from declared
relationships among users. The goal of our work is to extract an underlying hidden and
sparse network which more strongly represents the actual interactions among users. We
study how to leverage Twitter activities like micro-blogging and the network structure to ... Vis mindre

A network of people having established trust relations and a model for propagation
of related trust scores are fundamental building blocks in many of today's most successful e-
commerce and recommendation systems. However, the web of trust is often too sparse to
predict trust values between non-familiar people with high accuracy. Trust inferences are
transitive associations among users in the context of an underlying social network and may
provide additional information to… Vis mer

A network of people having established trust relations and a model for propagation
of related trust scores are fundamental building blocks in many of today's most successful e-
commerce and recommendation systems. However, the web of trust is often too sparse to
predict trust values between non-familiar people with high accuracy. Trust inferences are
transitive associations among users in the context of an underlying social network and may
provide additional information to alleviate the consequences of the sparsity and possible ... Vis mindre

Security Engineering Techniques and Solutions for Information Systems: Management and Implementation

Emergent networks like mobile ad hoc networks, sensor networks, opportunistic networks,
peer-to-peer networks and social networks are introducing new and exciting opportunities of
communication between people and devices. But these dynamic networks also introduce
many security-and privacy-related challenges. When dealing with complex and dynamic
environments, information about the current level of security or privacy, expressed in a
quantified manner, could be of great value… Vis mer

Emergent networks like mobile ad hoc networks, sensor networks, opportunistic networks,
peer-to-peer networks and social networks are introducing new and exciting opportunities of
communication between people and devices. But these dynamic networks also introduce
many security-and privacy-related challenges. When dealing with complex and dynamic
environments, information about the current level of security or privacy, expressed in a
quantified manner, could be of great value in a decision-making process. In order to ... Vis mindre

The Internet form a globally distributed network that provides a ubiquitous medium for interaction, the exchange of ideas, and commerce. The web is pervading our everyday lives in ways that were unimaginable even ten years ago. The evolving use of the web requires robust and efficient trust and reputation management mechanisms. During the past decade, online trust and reputation systems have provided cogent answers to emerging challenges in the global computing infrastructures relating to… Vis mer

The Internet form a globally distributed network that provides a ubiquitous medium for interaction, the exchange of ideas, and commerce. The web is pervading our everyday lives in ways that were unimaginable even ten years ago. The evolving use of the web requires robust and efficient trust and reputation management mechanisms. During the past decade, online trust and reputation systems have provided cogent answers to emerging challenges in the global computing infrastructures relating to computer and network security, electronic commerce, virtual enterprises, social networks and cloud computing. The goal of these systems in such global computing infrastructures is to allow entities to reason about the trustworthiness of other entities and to make autonomous decisions on the basis of trust. This requires the development of computational trust models that enable entities to reason about trust and to verify the properties of a particular interaction. The robustness of these mechanisms, which is one of the critical factors for the success of this technology, is currently not being sufficiently addressed. The global computing infrastructure is highly dynamic with continuously appearing and disappearing entities and services. It is vital that the associated computational trust model is able to incorporate this dynamism and that equally flexible legislative and regulatory frameworks emerge. In this thesis, we present an overview of the characteristics of the existing characteristics of the existing online trust and reputation models and systems through a multidimensional framework, which can serve as a basis to understand the current state of the art in the area. The critical open challenges that limit the effectiveness of today’s trust and reputation systems are discussed by providing a comprehensive literature review ... Vis mindre

A network of people having established trust relations and a model for propagation of
related trust scores are fundamental building blocks in many of todayŠs most successful e-
commerce and recommendation systems. Many online communities are only successful if
sufficient mutual trust between their members exists. Users want to know whom to trust and
how much to trust in the competence and benevolence of other community members in a
specific application domain. However, the… Vis mer

A network of people having established trust relations and a model for propagation of
related trust scores are fundamental building blocks in many of todayŠs most successful e-
commerce and recommendation systems. Many online communities are only successful if
sufficient mutual trust between their members exists. Users want to know whom to trust and
how much to trust in the competence and benevolence of other community members in a
specific application domain. However, the web of trust is often too sparse to predict trust ... Vis mindre

We present a knowledge-intensive and model-based case-based reasoning
framework that supports the truster for situation-aware trust management. The suggested
method augments the typically sparse trust information by inferring the missing information
from other situational conditions, and can better support situation-aware trust management.
Our framework can be coupled with existing trust management models to make them
situation-aware. It uses the underlying model of trust… Vis mer

We present a knowledge-intensive and model-based case-based reasoning
framework that supports the truster for situation-aware trust management. The suggested
method augments the typically sparse trust information by inferring the missing information
from other situational conditions, and can better support situation-aware trust management.
Our framework can be coupled with existing trust management models to make them
situation-aware. It uses the underlying model of trust management to transfer trust ... Vis mindre

The Internet form a globally distributed network that provides a ubiquitous medium for
interaction, the exchange of ideas, and commerce. The web is pervading our everyday lives
in ways that were unimaginable even ten years ago. The evolving use of the web requires
robust and efficient trust and reputation management mechanisms. During the past decade,
online trust and reputation systems have provided cogent answers to emerging challenges
in the global computing… Vis mer

The Internet form a globally distributed network that provides a ubiquitous medium for
interaction, the exchange of ideas, and commerce. The web is pervading our everyday lives
in ways that were unimaginable even ten years ago. The evolving use of the web requires
robust and efficient trust and reputation management mechanisms. During the past decade,
online trust and reputation systems have provided cogent answers to emerging challenges
in the global computing infrastructures relating to computer and network security, ... Vis mindre

Computational applications now go beyond personal computing, facilitating
collaboration and social interactions. Social computing is an area of information technology
concerned with the intersection of human and social studies connected by computer
networks. The primary goal of this article is to provide a brief survey of three popular social
computing services: recommender systems, trust/reputation systems, and social networks.
We approach these services from a data… Vis mer

Computational applications now go beyond personal computing, facilitating
collaboration and social interactions. Social computing is an area of information technology
concerned with the intersection of human and social studies connected by computer
networks. The primary goal of this article is to provide a brief survey of three popular social
computing services: recommender systems, trust/reputation systems, and social networks.
We approach these services from a data representation perspective and discuss two of ... Vis mindre

The most recent developments in computing technology, in particular, the emergence of a
new generation of versatile mobile devices will evoke a world in which we nearly always are
electronically connected with our environment. In the field of Electronic Commerce, this
prospect will offer us undreamed-of business opportunities. It may, however, also cause new
security and privacy threats which have to be tackled in order to achieve acceptance for the
novel trading… Vis mer

The most recent developments in computing technology, in particular, the emergence of a
new generation of versatile mobile devices will evoke a world in which we nearly always are
electronically connected with our environment. In the field of Electronic Commerce, this
prospect will offer us undreamed-of business opportunities. It may, however, also cause new
security and privacy threats which have to be tackled in order to achieve acceptance for the
novel trading possibilities. For instance, we do not want to be bothered by a flood of ... Vis mindre

he majority of trust models consider two types of knowledge in estimating the trustworthiness of a trustee in an interaction: experiences and recommendations. However, this leads to a nested trust problem; how could we trust the recommendations? Even when the recommenders are not deceptive, there is still a trust related problem due to the subjectivity of human judgment. This paper describes a missing part of the existing trust management models: handling the subjectivity of recommendations… Vis mer

he majority of trust models consider two types of knowledge in estimating the trustworthiness of a trustee in an interaction: experiences and recommendations. However, this leads to a nested trust problem; how could we trust the recommendations? Even when the recommenders are not deceptive, there is still a trust related problem due to the subjectivity of human judgment. This paper describes a missing part of the existing trust management models: handling the subjectivity of recommendations. Our approach is based on the idea that a recommender's judgment method can be inferred and the recommended entity can be (re)evaluated according to the value system of the truster who is about to make a decision. Extraction of the judgment method involves abductive reasoning which is implemented in the proposed account using subjective logic. This approach has been quantitatively compared with two other methods. Our experiments show that our proposed solution outperforms an extended version of the "Beta trust model"​, a trust model without subjectivity elimination. Our suggested method for trust and reputation systems may also be applied to other systems that include a rating mechanism such as recommender systems. Vis mindre

Mobile news recommender systems help users retrieve news that is relevant in their particular context and can be presented in ways that require minimal user interaction. In spite of the availability of contextual information about mobile users, though, current mobile news applications employ rather simple strategies for news recommendation. Our multi-perspective approach unifies temporal, locational, and preferential information to provide a more fine-grained recommendation strategy. This demo… Vis mer

Mobile news recommender systems help users retrieve news that is relevant in their particular context and can be presented in ways that require minimal user interaction. In spite of the availability of contextual information about mobile users, though, current mobile news applications employ rather simple strategies for news recommendation. Our multi-perspective approach unifies temporal, locational, and preferential information to provide a more fine-grained recommendation strategy. This demo paper presents the implementation of our solution to efficiently recommend specific news articles from a large corpus of newly-published press releases in a way that closely matches a reader's reading preferences. Vis mindre

Twitter is today the most prominent micro-blogging service available on the Web.
Information overload is a major problem on most online social networks and particularly on
Twitter. It is difficult to find the right people and content to focus on. Personalized and trust-
based recommender systems have emerged as a solution to alleviate this problem on online
social networks. However, there is no explicit trust network on Twitter. In this paper, we study
how to leverage Twitter… Vis mer

Twitter is today the most prominent micro-blogging service available on the Web.
Information overload is a major problem on most online social networks and particularly on
Twitter. It is difficult to find the right people and content to focus on. Personalized and trust-
based recommender systems have emerged as a solution to alleviate this problem on online
social networks. However, there is no explicit trust network on Twitter. In this paper, we study
how to leverage Twitter activities and network structure to find a simple, efficient, but yet ... Vis mindre

The Internet and the World Wide Web together form a globally distributed network
that provides a ubiquitous medium for interaction, the exchange of ideas, and commerce.
The web is pervading our everyday lives in ways that were unimaginable even ten years
ago. The evolving use of the web requires robust and efficient trust and reputation
management mechanisms. Despite numerous proposals on trust and reputation systems,
designing a robust and reliable system is still largely… Vis mer

The Internet and the World Wide Web together form a globally distributed network
that provides a ubiquitous medium for interaction, the exchange of ideas, and commerce.
The web is pervading our everyday lives in ways that were unimaginable even ten years
ago. The evolving use of the web requires robust and efficient trust and reputation
management mechanisms. Despite numerous proposals on trust and reputation systems,
designing a robust and reliable system is still largely an open challenge, especially in the ... Vis mindre

The majority of existing trust and reputation models consider two types of
knowledge in estimating the trustworthiness of a trustee in an interaction: personal direct
experiences and recommendations from third parties. However, previous direct and
recommended evidence is not available for new users. In addition, a new user joins the
system with a neutral reputation value in most systems and must participate in interactions
with others in order to raise its reputation score… Vis mer

The majority of existing trust and reputation models consider two types of
knowledge in estimating the trustworthiness of a trustee in an interaction: personal direct
experiences and recommendations from third parties. However, previous direct and
recommended evidence is not available for new users. In addition, a new user joins the
system with a neutral reputation value in most systems and must participate in interactions
with others in order to raise its reputation score. Users usually tend to interact with high ... Vis mindre

Trust is a fundamental concern in electronic transactions and behavior of people
are influenced by the situation. Motivated by that we present a state-of-the-art survey of
context representation in trust management and provide main directions along which
research efforts have been done. We propose a generalized model which considers
different aspects of the relationship between context-awareness and trust management.

Recommending news articles entails additional requirements to recommender
systems. Such requirements include special consumption patterns, fluctuating
itemcollections, and highly sparse user profiles. This workshop (NRS'13@ RecSys) brought
together researchers and practitioners around the topics of designing and evaluating novel
news recommender systems. Additionally, we offered a challenge allowing participants to
evaluate their recommendation algorithms with actual user… Vis mer

Recommending news articles entails additional requirements to recommender
systems. Such requirements include special consumption patterns, fluctuating
itemcollections, and highly sparse user profiles. This workshop (NRS'13@ RecSys) brought
together researchers and practitioners around the topics of designing and evaluating novel
news recommender systems. Additionally, we offered a challenge allowing participants to
evaluate their recommendation algorithms with actual user feedback. Vis mindre