Search engines are used to gather and collect information. This interaction sometimes influences the user and changes their attitude towards a topic after such interaction. Prior work has shown that it is a complex endeavour to understand attitude change, as there are many things that can influence a user during a search session. One of the aspects that have not been researched is the influence of informedness. Therefore we examine the role of informedness in attitude change. To do that, we first defined what a well-informed user in the context of web search is. Then a user study is conducted to understand informedness’s role in attitude change. From the platform Prolific, we recruited participants (N=320) for the main user study. The experiment is a 3 x 3 (Informedness level x SERP viewpoint bias) factorial between-subjects study and it requires interaction with the provided search results. The participants were placed in one of three categories, ”Well Informed”, ”Mildly Informed”, and ”Uninformed”, based on their results on a knowledge questionnaire. We created 3 different conditions for the search engine results page (SERP). The SERP had a viewpoint-biased ranking that was either supportive, opposing or balanced towards the topic. There were two topics, abortion and obesity, to which the participants were assigned. Our findings showed that 37% of the participants with a valid submission had changed attitudes. The findings from the user study suggest that the level of informedness does not play a role in facilitating attitude change among users during a web search. This has implications for the design of information retrieval systems and web search experiences in general.

Switching energy suppliers can be a time consuming process and the manner in which permissions regarding consumer data are stored lacks transparency. To overcome these issues, a solution was proposed in the form of a mandate register. Said register keeps track of which consumer gave what permission, regarding energy data, to whom. In this project a prototype of such a register was built. The register is required to be designed in such a way that it is expandable and secure. From these characteristics, the conclusion was drawn that a permissioned blockchain network was the most suitable option for storing mandates in a decentralised and immutable fashion. The most fitting consensus algorithm for the blockchain network was determined to be the Raft algorithm. For implementation of the blockchain network, a widely-documented and advanced framework called Hyperledger Fabric was used, which was be configured to use Raft. A network in Hyperledger Fabric is a set of organisations of which subsets can form channels together. Each organisation consists of multiple peer nodes, each with a corresponding ledger, database and smart contracts. The mandate register network consists of two channels, the first containing seven organisations, with two peer nodes per organisation. Apart from these seven organisations, the network contains seven orderers, which work in the second channel and which are responsible for managing transactions made by an application. On top of the network, an application was built that connects to the network and functions as a simple web server. The web server allows consumers to submit their mandates as input to the network and query mandates from the network. Performance evaluation of the network shows that it requires much optimisation before being ready for deployment in the real world. Apart from optimisation, there are various tasks related to security, authentication, deployment, and the GDPR which have to be completed before the register can be used in production.