Acta Informatica Pragensia

1-17

Authors: Waleed M. Al-Adrousy, Hesham Ali, Taher Hamza

Social networks have become a new trend for research among computer scientist around the world. Social network had an impact on users' way of life. One of social network usages is recommendation systems. The need of recommendation systems is arising when users try to know best choice for them in many items types (books, experts, locations, technologies...etc). The problem is that a single person can't try all alternatives in all possibles life goals to compare. Thus, a person has to use his friends' expertise to select better option in any item category. This process is the main idea of “Recommendation Systems”. Recommendation systems usually depend on users-to-items ratings in a network (graph). Two main challenges for recommendation systems are accuracy of recommendation and computation size. The main objective of this paper is to introduce a suggested technique for transitive recommendation system based on users' collaborative ratings, and also to balance loading of computation. All this has to be applied on a special type of social network. Our work studied the transitivity usage in connections to get a relation (path) as a recommendation for nodes not directly connected. The target social network has eight types of nodes. So, there are techniques that are not suitable to this complex type of network. Those we can present a new support for recommending items of several types to users with several types. We believe that this functionality hasn't been fully provided elsewhere. We have suggested using single source shortest path algorithm combined with Map Reduce technique, and mathematically deduced that we have a speeding up of algorithm by 10% approximately. Our testing results shows an accuracy of 89% and false rejection of 99% compared to traditional algorithms with less configuration parameters and more steady count of recommendations.

25-38

Authors: Miroslav Hudec

The Structured Query Language (SQL) has been established as a standard for querying relational databases. However, users face the problem how to define their requirements for data by the exact query conditions. This work examines advantages of fuzzy queries, which provide a better representation of the user requirements by expressing imprecise conditions through linguistic terms. Further, the paper discusses solving empty and overabundant answer problems, revealing similarities in database entities and applying preferences in query conditions. Finally, paper discusses practical realisations of fuzzy queries.

39-56

Authors: Peter Fanfara, Martin Chovanec

In the current development of technologies, rapid growth of computer networks and distributed systems still exist a very probable risk of attack. There have been developed and implemented a number of solutions to help in detecting and/or preventing attacks and to improve the actual system security. The most common solution is to use Intrusion Detection System (IDS) in cooperation with the firewall. Neither the IDS nor firewall can respond in real time to a specific type of attack. This paper deals with the detection mechanism based on Honeypot technology and its use in the proposed architecture to improve security of computer systems. The essence of the work is to show how can sophisticated hybrid Honeypot influence the design of IDS architecture and thus increase its efficiency.

70-78

Authors: Václav Nádvorník

It is useless to argue about statement that contemporary generation of students of elementary schools is the Internet generation. The aim of the article is to describe how children use the Internet, which parts of the Internet they use more and less. We can compare this finding out with the habits of teachers. The author made a survey among 630 students and 150 teachers from different schools in the Czech Republic. The article should be an inspiration for school web masters and for teachers. It can recommend them appropriate communication channels to students.

91-100

Authors: Anna Exnarová

This paper presents the proposal for application of systems thinking in the application development process. The models of systems thinking present to the reader the possibility of their use and application in the software application development process. The proposal does not mandate the creation of a specific model at some point, but suggests how the selected models can be used. Authorial intention is to change the mental model of the reader – particularly the part that contains an image of the application of systems thinking in developing applications.

122-124

Authors: Tomáš Klíma

Review of the Kevin Mitnick´s book Art of deception. This book introduces to us the social engineering as complementary tool to technically-based approaches to penetration of information security of organisations. Unlike these approaches the social engineering doesn´t become obsolete so fast which means this book has a value for the IT security guys as well as for the end users who are the main victims of social engineering.