Evaluating Digital Libraries: A Longitudinal and Multifaceted View

published or submitted for publicatio

USABILITY TESTING OF INTERACTIVE SYSTEMS CONDUCTED BY UNIVERSITY STUDENTS DURING A PANDEMIC

This case study describes a usability testing course in which students learn by practicing several evaluation methods. The on-campus format makes it possible for teachers and students to meet to discuss recorded test sessions and students can observe other students’ execution of pilot studies conducted on campus. The COVID-19 pandemic placed new demands on this course. In-person activities were avoided by some students and many test participants. Some student teams tried remote usability testing. Interestingly, screen recordings (with sound) of the test sessions show that remote testing sometimes helped the students focus more on observation and less on (inappropriately) guiding the test subjects. Another effect was that the students found it easier to recruit participants than during the previous years when the university was teeming with students, lecturers, and non-academic staff. However, the recruited participants were often notably limited to the students’ circles of friends

Chaotic iterations versus Spread-spectrum: chaos and stego security

A new framework for information hiding security, called chaos-security, has been proposed in a previous study. It is based on the evaluation of unpredictability of the scheme, whereas existing notions of security, as stego-security, are more linked to information leaks. It has been proven that spread-spectrum techniques, a well-known stego-secure scheme, are chaos-secure too. In this paper, the links between the two notions of security is deepened and the usability of chaos-security is clarified, by presenting a novel data hiding scheme that is twice stego and chaos-secure. This last scheme has better scores than spread-spectrum when evaluating qualitative and quantitative chaos-security properties. Incidentally, this result shows that the new framework for security tends to improve the ability to compare data hiding scheme