Comparison of Filter Techniques for Two-Step Feature Selection

In the last decade, the processing of the high dimensional data became inevitable task in many areas of research and daily life. Feature selection (FS), as part of the data processing methodology, is an important step in knowledge discovery. This paper proposes nine variation of two-step feature selection approach with filter FS employed in the first step and exhaustive search in the second step. The performance of the proposed methods is comparatively analysed from the stability and predictive performance point of view. As the obtained results indicate the choice of the filter FS in the first stage has strong influence on the resulting stability. Here, the choice of univariate Pearson correlation coefficient based FS method appears to provide the most stable results

Security Measures in Automated Assessment System for Programming Courses

A desirable characteristic of programming code assessment is to provide the learner the most appropriate information regarding the code functionality as well as a chance to improve. This can be hardly achieved in case the number of learners is high (500 or more). In this paper we address the problem of risky code testing and availability of an assessment platform Arena, dealing with potential security risks when providing an automated assessment for a large set of source code. Looking at students’ programs as if they were potentially malicious inspired us to investigate separated execution environments, used by security experts for secure software analysis. The results also show that availability issues of our assessment platform can be conveniently resolved with task queues. A special attention is paid to Docker, a virtual container ensuring no risky code can affect the assessment system security. The assessment platform Arena enables to regularly, effectively and securely assess students' source code in various programming courses. In addition to that it is a motivating factor and helps students to engage in the educational process

UTILIZATION OF VIDEOCONFERENCES IN EDUCATIONAL ENVIRONMENT

Abstract. The progress in the information technologies has impact not only in the area of computer sciences, but also in the area of education. Following this trend, students have not only a great oportunity to search for the information resources on the Internet, but they can also use plenty of media with various information for their study. Nowadays the number of services providing not only the textual information, but also multimedia information, is growing. Many of them have educational character, so they can be used for wide educational purposes. This paper is focused to the problem of videoinformation usage for the educational purposes; the usage of videoconferences for the distance learning; and the usage of distributed systems for the creation of archive service of multimedia content based on the running videoconferences, which can be used later in the educational process. In this paper also an idea of creating a formal model of presented distributed system is imposed, with regard to its use within an educational process in all aspects of system’s design and implementation