University of Piraeus

About: University of Piraeus is a education organization based out in Piraeus, Attiki, Greece. It is known for research contribution in the topics: Context (language use) & Computer science. The organization has 1731 authors who have published 6209 publications receiving 106699 citations.

The effect of preprocessing techniques on Twitter sentiment analysis

Abstract: As Twitter offers a fertile ground for expressing different thoughts and opinions, it can be seen as a valuable tool for sentiment analysis. Furthermore, properly identified reviews present a baseline of information as an input to different systems, such as e-learning systems, decision support systems etc. However, the data preprocessing is a crucial step in sentiment analysis, since selecting the appropriate preprocessing methods, the correctly classified instances can be increased. In view of the above, this research paper explains the necessary information to get preprocess the reviews in order to find sentiment and make analysis whether it is positive or negative. Extended comparison of sentiment polarity classification methods for Twitter text and the role of text preprocessing in sentiment analysis are discussed in depth. In the set of tests, possible combinations of methods and report on their efficiency were included, conducting experiments using manually annotated Twitter datasets. Finally, it is proved that feature selection and representation can affect the classification performance positively.

Secure Transactions with Mobile Agents in Hostile Environments

Abstract: A major problem of mobile agents is their apparent inability to authenticate transactions in hostile environments. In this paper, we consider a framework for the prevention of agent tampering without compromising the mobility or autonomy of the agent. Our approach uses encrypted functions. We present an RSA implementation which answers affirmatively the open problem on undetachable signatures of Sander and Tschudin.