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Sarah Bouraga

Bio: Sarah Bouraga is an academic researcher from Université de Namur. The author has contributed to research in topics: Requirements engineering & Computer science. The author has an hindex of 4, co-authored 16 publications receiving 76 citations.

Papers
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Journal ArticleDOI
TL;DR: An analysis of the research introducing new consensus protocols and a comprehensive classification framework, integrating knowledge from multiple works in the literature, as well as introducing classification dimensions that have not been proposed before are presented.
Abstract: Blockchain, the underlying technology of Bitcoin, refers to the public ledger used in a distributed network. Because blockchain does not rely on a central authority, peers have to agree on the state of the ledger among themselves, i.e., they have to reach a consensus on the state of the transactions. The way nodes reach that consensus has gained incredible attention in the literature. Bitcoin uses the Proof-of-Work (PoW) mechanism, as did Ethereum at first. The latter decided to move from PoW to Proof-of-Stake (PoS) because of the high energy consumption required by PoW. To date, many other consensus protocols have been proposed to address the limitations of the seminal ones. In this paper, we inform researchers and practitioners about the current state of consensus protocols research. The aim is to provide an analysis of the research introducing new consensus protocols in order to enable a more unified treatment. To that end, we review 28 new consensus protocols and we propose a four-category classification framework: Origin, Design, Performance and Security. We demonstrate the applicability of the framework by classifying the 28 protocols. Many surveys have already been proposed in the literature and some of them will be discussed later in the paper. Yet, we believe that this work is relevant and important for two reasons. Firstly, blockchain being a fast evolving topic, new consensus protocols emerge regularly and improvements are also put forward on a regular basis. Hence, this work aims at reflecting the latest state-of-the-art in terms of consensus protocols. Secondly, we aim to propose a comprehensive classification framework, integrating knowledge from multiple works in the literature, as well as introducing classification dimensions that have not been proposed before. This work demonstrates that multiple consensus have been proposed in a short period of time, and highlights the differences between these protocols. Furthermore, it is suggested that researchers and practitioners who aim to propose consensus protocols in the future should pay attention to all the dimensions presented in the classification framework.

87 citations

Journal ArticleDOI
TL;DR: This survey overviews the main ideas characterizing a Knowledge-Base Recommendation Systems (KBRS), using a classification framework, and discusses KBRS components, user problems for which recommendations are given, knowledge content of the system, and the degree of automation in producing recommendations.
Abstract: Knowledge-Base Recommendation (or Recommender) Systems (KBRS) provide the user with advice about a decision to make or an action to take. KBRS rely on knowledge provided by human experts, encoded in the system and applied to input data, in order to generate recommendations. This survey overviews the main ideas characterizing a KBRS. Using a classification framework, the survey overviews KBRS components, user problems for which recommendations are given, knowledge content of the system, and the degree of automation in producing recommendations.

57 citations

Proceedings ArticleDOI
11 Sep 2014
TL;DR: This paper proposes requirements patterns for Online Social Networks, based on features observed on currently popular OSNs, and are defined as i-star models, which can be used as basic models of OSN requirements.
Abstract: This paper proposes requirements patterns for Online Social Networks (OSNs). Patterns are based on features observed on currently popular OSNs, and are defined as i-star models. Patterns are relevant for the requirements engineering of new OSNs. They can help in requirements elicitation, in order to avoid missing important OSN requirements. They can be used as basic models of OSN requirements, something that a modeler starts from, and then specializes and changes according to the specific requirements from OSN stakeholders.

8 citations

Journal ArticleDOI
TL;DR: A set of event types, which can generate notifications to users on an OSN, and the factors, which influence the perception of the relative importance ofevent types are identified.
Abstract: Over the last decade, online social networks (OSNs) have been growing quickly to become some of the largest systems in use. Their users are sharing more and more content, and in turn have access to vast amounts of information from and about each other. This increases the risk of information overload for every user. We define a set of event types, which can generate notifications to users on an OSN. We survey one set of users to obtain their evaluation of the relative importance of event types. We survey another set of users, to identify the factors, which influence the perception of the relative importance of event types. Both results are relevant for the design of algorithms for the recommendation of content to OSN users.

7 citations

Proceedings ArticleDOI
27 Sep 2021
TL;DR: In this article, the authors proposed a correlation analysis between various NFTs' characteristics and the popularity of the NFT, which can have practical implications for both designers and users.
Abstract: Blockchain technology supports digital assets, which can take the form of cryptocurrencies and tokens. Tokens are usually created on top of the blockchain platform, using smart contracts. Two main categories of tokens exist: Fungible Tokens and Non-Fungible Tokens (NFTs). Here, we focus on NFTs and propose a correlation analysis between various NFTs' characteristics and the popularity of the NFTs. The results can have practical implications for both designers and users.

6 citations


Cited by
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Journal Article
TL;DR: In this paper, a formal framework for reasoning with goal models is presented, in particular, a qualitative and a numerical axiomatization for goal modeling primitives and introduces label propagation algorithms that are shown to be sound and complete with respect to their respective axioms.
Abstract: Over the past decade, goal models have been used in Computer Science in order to represent software requirements, business objectives and design qualities. Such models extend traditional AI planning techniques for representing goals by allowing for partially defined and possibly inconsistent goals. This paper presents a formal framework for reasoning with such goal models. In particular, the paper proposes a qualitative and a numerical axiomatization for goal modeling primitives and introduces label propagation algorithms that are shown to be sound and complete with respect to their respective axiomatizations. In addition, the paper reports on preliminary experimental results on the propagation algorithms applied to a goal model for a US car manufacturer.

292 citations

Journal ArticleDOI
TL;DR: An extensive survey on the applications of blockchain for the metaverse and the impact of blockchain on key-enabling technologies in the Metaverse, including Internet-of- Things, digital twins, multi-sensory and immersive applications, artificial intelligence, and big data is investigated.

94 citations

Journal ArticleDOI
TL;DR: In this paper, the authors argue that activity theory, as a theory of practice, can help overcome long-standing challenges in the field of information systems (IS) by better accounting for the material in work and social activity.
Abstract: Purpose This theory development paper argues that activity theory, as a theory of practice, can help overcome long-standing challenges in the field of information systems (IS) by better accounting for the material in work and social activity. It also suggests ways in which IS research can inform the development of activity theory. In this way, this paper seeks to be forward-looking as much as reflective to advance an enlarged understanding of activity theory, and argue for its development in IS studies. Design/methodology/approach The paper is conceptual and draws upon existing literature and research to propose and cultivate an updated understanding of activity theory as a theoretical lens capable of accounting for social and technical aspects in IS. Findings The paper has three aims. First, to cultivate the use of activity theory in IS. It elaborates on the use and contribution of activity theory in IS, charts it’s use over the last 20 years and discusses how it brings together a range of ideas that hav...

67 citations

Journal ArticleDOI
01 Apr 2019
TL;DR: In this paper, a knowledge-aware recommender system is proposed, where the key issue is how to obtain rich and structured knowledge base (KB) information for recommender systems items.
Abstract: To develop a knowledge-aware recommender system, a key issue is how to obtain rich and structured knowledge base (KB) information for recommender system (RS) items. Existing data sets or methods ei...

44 citations

Proceedings Article
01 Jan 2018
TL;DR: This paper presents KB4Rec v1.0, a data set linking KB information for RSs, which has linked three widely used RS data sets with two popular KBs, namely Freebase and YAGO.
Abstract: To develop a knowledge-aware recommender system, a key data problem is how we can obtain rich and structured knowledge information for recommender system (RS) items. Existing datasets or methods either use side information from original recommender systems (containing very few kinds of useful information) or utilize private knowledge base (KB). In this paper, we present the first public linked KB dataset for recommender systems, named KB4Rec v1.0, which has linked three widely used RS datasets with the popular KB Freebase. Based on our linked dataset, we first preform some interesting qualitative analysis experiments, in which we discuss the effect of two important factors (i.e. popularity and recency) on whether a RS item can be linked to a KB entity. Finally, we present the comparison of several knowledge-aware recommendation algorithms on our linked dataset.

43 citations