Blockchain Papers

Lin Liu, Wei‐Tek Tsai, Md Zakirul Alam Bhuiyan, Dong Yang

No abstract is available for this record.

Jean-Marc Seigneur, Sophie Pusterla, Xavier Socquet-Clerc

Relational capital for companies has been theorized and modeled in the past, but so far, no real Web application has tried to bring its value to light, especially concerning the real estate application domain. In this paper, we present the results of our surveys on how the types of relations who have contributed to a product impact price premium and what real estate agencies think about real estate relational value, especially as implemented on our Web marketplace connected to Facebook social network and NEO public blockchain for products certifications transparency.

Rui Hu, Wei Yan

Although our communities are paying extensive attention to the blockchain technology, it is still far away from realistic applications. Thus, this red-hot technology could be understood and employed for visual applications. Authors focus on online videos that collect sufficient user clicks owning to the high demand every day. When people watch the videos of TV drama episodes in an online website, they often need to exactly organise the playlists in ascending or descending order. However, video websites such as YouTube can't provide this service due to multiple reasons. This chapter creates a private blockchain for these video websites and applies Merkle tree to store the sorted videos in the chain. A sorted playlist has been created in the video website. Getting out of the box of video search so as to provide a quick video ranking solution is authors' main task. Sorting results are evaluated by using edit distance.

Alexander Mikroyannidis, Allan Third, John Domingue

Blockchain technology provides a decentralised peer-to-peer infrastructure, supporting openness, transparency, accountability, identity management and trust. As such, the Blockchain has the potential to revolutionise education in a number of ways. Blockchain technology offers opportunities to thoroughly rethink how we find educational content and training services online, how we register and pay for them, as well as how we get accredited for what we have learned and how this accreditation affects our career trajectory. This paper explores a case study on the decentralisation of lifelong learning using Blockchain technology. In particular, we investigate the different scenarios and requirements for making online education and lifelong learning more open and decentralised, while placing lifelong learners in control of their learning process and its associated data. Additionally, we discuss various approaches to the Semantic Blockchain and the applications of these approaches on education.

Weihong Cai, Xin Du, Jianlong Xu

Personalized quality of service (QoS) prediction plays an important role in helping users build high-quality service-oriented systems. To obtain accurate prediction results, many approaches have been investigated in recent years. However, these approaches do not fully address untrustworthy QoS values submitted by unreliable users, leading to inaccurate predictions. To address this issue, inspired by blockchain with distributed ledger technology, distributed consensus mechanisms, encryption algorithms, etc., we propose a personalized QoS prediction method for web services that we call blockchain-based matrix factorization (BMF). We develop a user verification approach based on homomorphic hash, and use the Byzantine agreement to remove unreliable users. Then, matrix factorization is employed to improve the accuracy of predictions and we evaluate the proposed BMF on a real-world web services dataset. Experimental results show that the proposed method significantly outperforms existing approaches, making it much more effective than traditional techniques.

Raheleh Hassannia, Ali Vatankhah Barenji, Zhi Li, Habib Alipour

The purpose of the study is to design and develop a recommended system based on agent and web technologies, which utilizes a hybrid recommendation filtering for the smart tourism industry. A hybrid recommendation system based on agent technology is designed by considering the online communication with other sectors in the tourism industry, such as the tourism supply chain, agency etc. However, online communication between the sectors via agents is designed and developed based on the contract net protocol. Furthermore, the design system is developed on the java agent development framework and implemented as a web application. Case study-based results considering two scenarios involving 100 customers illustrated that the proposed web application improves the rate of the recommendation for the customers. In the first scenario without disturbances, this rate was improved by 20% and the second scenario with disturbances yielded a 30% rate of acceptable recommendation. In addition, based on the second scenario, real time data communication on the system occurred, thus the proposed system supported real time data communication.

Kosuke Komiya, Tatsuo Nakajima

No abstract is available for this record.

Haoxuan Li, Hui Huang, Shichong Tan, Ning Zhang · 6 authors

Reputation evaluation system, as the publisher and analyser of evaluation, is an important influencing factor for users and sellers in online business. Traditional reputation evaluation system always requires a third party to achieve the operation of analysis and publishment. However, a third party often exposes the identity of the users, and leaks the information. As far as we know, all existing revocable reputation evaluations are based on the third-party model. In this paper, we present a new reputation evaluation system based on blockchain. Compared with traditional reputation evaluation systems, our system removes the third party, it allows users to modify their own evaluation information. Moreover, the user's privacy also can be protected. The experiment performance demonstrates that the overhead of the system is acceptable, the system is feasible and efficient.

Abdullah Al Omar, Rabeya Bosri, Mohammad Shahriar Rahman, Nasima Begum · 5 authors

No abstract is available for this record.

Andrea Lisi, Andrea De Salve, Paolo Mori, Laura Ricci

No abstract is available for this record.

Shuai Wang, Chenchen Huang, Juanjuan Li, Yong Yuan · 5 authors

Since first coined by Google in 2012, knowledge graph has received extensive attention from both industry and academia, and has been widely used in many scenarios with success, e.g. information retrieval, online recommendation, question-answering, and so on. However, traditional centralized construction of knowledge graph faces many challenges, such as laborious and time-consuming, vulnerable to manipulation or tampering, lacking scrutiny, among others. Therefore, in this paper, we propose a novel decentralized knowledge graph construction method by means of crowdsourcing, and the business logic of crowdsourcing is implemented by blockchain-powered smart contracts to guarantee the transparency, integrity, and auditability. On this basis, the decentralized knowledge graph is used for a deep recommender system, and case studies validate the effectiveness of the system. This paper is aimed at providing a novel decentralized approach for constructing knowledge graph and serving as reference and guidance for future research and practical applications of knowledge graph.

Χρήστος Δουλκερίδης

As data generation becomes increasingly inherently distributed, either due to usergenerated (multimedia) content or because of application-specific needs (sensor networks, data streams, etc.), traditional centralized architectures fail to address the new challenges of contemporary data management.A promising solution for the design and deployment of global-scale applications is the exploitation of the peer-to-peer (P2P) paradigm.P2P has emerged as a powerful model for organizing and searching large data repositories distributed over autonomous independent sources.The main topic and contribution of this thesis is the unsupervised organization of content into Semantic Overlay Networks (SONs), in a decentralized and distributed manner, and subsequently a variety of techniques for efficient searching and query processing in unstructured P2P systems.SONs have been proposed in the relevant research literature, as a way to organize peers into thematic groups, thereby enabling query routing to specific peer groups in a deliberate way, instead of blind forwarding.In particular, this work focuses on unstructured P2P networks that preserve peer autonomy.A novel protocol for unsupervised, distributed and decentralized SON construction is proposed, named DESENT [35,38], which employs distributed clustering of peer contents, respecting the requirements imposed by the distributed nature of the environment [138].Exploiting the generated SONs, we propose efficient routing strategies for answering similarity search queries [37,39].The approach is applied and tested in a distributed IR setting, aiming to address some of the limitations of P2P IR/web search.Towards this goal, a distributed dimensionality reduction algorithm is proposed [96], in order to reduce the high-dimensional feature space and improve clustering quality.Assuming a super-peer architecture we propose an approach called SIMPEER [43] that efficiently supports similarity search over data distributed over a large set of peers.We show how range queries and nearest neighbor queries can be processed.We also explore how to support non-traditional queries (such as top-k [141] and skylines [139]) that involve ranking.Furthermore, by relaxing the restriction of completely unsupervised environment and assuming a semi-supervised context, a novel technique for P2P summary caching of hierarchical information is presented, exploiting either predefined taxonomies [104] or XML schema information [36,40], which is applied in mobile P2P context-aware environments to improve query routing [45,44].6.4 Measurements from using different number of querying peers, given as the fraction of peers in the network. . . . . . . . . . . . . . . . .6.5 Measurements from using different skew (represented by increasing values of a) in the query distributions. . . . . . . . . . . . . . . . . .6.6 Measurements for different network

Georgia Koloniari, Evaggelia Pitoura

No abstract is available for this record.