The dissertation herein involves research in the field of the visual representations aided by semantic technologies and ontologies in order to support decisions and policy making procedures, in the framework of research and academic information systems. The visualizations will be also supported by data mining and knowledge extraction processes in the linked data environment. To elaborate, visual analytics’ techniques will be employed for the organization of the visualizations in order to present the information in such a way that will utilize the human perceptual abilities and that will eventually assist the decision support and policy making procedures. Furthermore, the visual representation and consequently the decision and policy making processes will be ameliorated by the means of the semantic technologies based on conceptual models in the form of ontologies. Thus, the main objective of the proposed doctoral thesis consists the combination of the key semantic technologies with interactive visualisations techniques based mainly on graph’s perception in order to make decision support systems more effective. The application field will be the research and academic information systems.