Alen Lovrencic

University of Zagreb · Faculty of Organization and Informatics (FOI)

The circle sort algorithm was introduced in 2005 by Bezemer and Olufem, and it is still not completely researched. The experiments show that the algorithm is comparable with the Shell sort algorithm. Its complexity is still not definitely determined. This paper gives optimized circle sort algorithm, which proved to be up to 25% faster than the orig...

Knjiga pokriva osnove ocjene složenosti algoritama i struktura podakaka. Primjeri koji su u knjizi dani uglavnom pokrivaju tematiku pretraživanja i sortiranja polja.

Knjiga daje uvod u programiranje u programskom jeziku C++, uključujući varijable, selekcije, iteracije, pokazivače, funkcije i rad s datotekama.

When information system is being designed we have to determine, in some way, a sequence/priority of development of its subsystems. There are many algorithms that can be immediately applied or modified to solve previously mentioned problem. Nevertheless, they have all been tested on randomly generated graphs which in certain cases may or may not rep...

Designing an information system demands intense efforts, although a lot of operations that are involved have a potential to be automated or semiautomated. In our previous work we developed advanced agents for automatic determination of IS subsystems through k-way cuts and automatic determination of IS subsystems execution order through an evolution...

In our previous research we have made literature analysis and discovered possible mind map application areas. We have pointed out why currently developed software and methods are not adequate and why we are developing a new one. We have defined system architecture and functionality that our software would have. After that, we proceeded with text-mi...

In our previous research we have constructed theoretical foundations for automated approach that can determine information system subsystems execution and development order according to data class interactions. In this paper, we will, from those theoretical foundations, develop C# algorithm through which we can see its real time behavior and calcul...

We present the modeling of dynamical systems and finding of their complexity indicators by the use of concepts from computation and information theories, within the framework of J. P. Crutchfield’s theory of ε-machines. A short formal outline of the -machines is given. In this approach, the dynamical systems are analyzed directly from the time seri...

A deductive system for database normalization is implemented by using a Flora-2 reasoning engine. The system allows for checking a relational schema up to Boyce- Codd normal form (BCNF) and functional independent normal form (FINF). Examples of system usage are presented and discussed.

At the moment information system subsystems ordering is mainly done according to business rules, and often arbitrarily. By contrast, we will devise an automated approach based on the information system subsystems communication through data classes, so that subsystems of an information system, if possible, do not use data classes that are not yet ge...

Development of graphical interfaces and visual programming concepts has created serious problems for the blinds regarding usage of computers and visualization. While this problem is still not so big regarding everyday computer usage it has become a major problem for blind programmers. In this paper we give an overview of major problems for the blin...

A deductive system for database normalization is implemented by using a Flora-2 reasoning engine. The system allows for checking a relational schema up to Boyce- Codd normal form (BCNF) and functional independent normal form (FINF). Examples of system usage are presented and discussed.

Data compression is important part of information and communication technologies. There are many benefits from using data compression, like saving space on hard drives or lowering use of transmission bandwidth in the network. There are also many algorithms and many tools that are used today in this field. In this paper we will focus on lossless dat...

The paper introduces Verificator, our learning programming interface aimed for learning programming in C++ at the university beginners' level. In teaching programming some specific problems concerning the teaching itself as well as the organization of the teaching process need to be considered. One of the biggest problems is that students tend to a...

Teaching programming at university beginner's level has some specific problems like wide diversity of student's previous knowledge, fear of programming, problems with programming language syntax etc., as shown in many previous researches and our on-line questionnaire. There are already some approaches and tools developed to make programming concept...

Fifty years ago one of the greatest breakthroughs in computer programming and in the history of computers happened – the appearance of FORTRAN, the first higher-order programming language. From that time until now hundreds of programming languages were invented, different programming paradigms were defined, all with the main goal to make computer p...

Rapid development of industry and economy requires quick and efficient education of large amount of theoretical knowledge and practical skills. In computer science, especially in programming, this trend is very noticeable and real experts are needed and hard to create. But new problem has emerged in higher education and its name is plagiarism. In o...

In facing the problem of building a complex yet fast and resource efficient Enterprise Resource Planning (ERP) or Extended Resource Planning (XRP) system the first obstacle is the creation of a Bill of Materials (BoM) algorithm, which is used to calculate material needs according to the production plan. Taking into consideration different possibili...

Living in a dynamic world requires rapid development of both web and desktop applications to support such trend in IT industry. Processes are becoming more complicated, and in turn more demanding. There are two problems regarding applications: development and maintenance. In this paper we are discussing optimization of applications code and re-usab...

In this paper we will present some schemes for strengthening network authentification over insecure channels with biometric concepts or how to securely transfer or use biometric characteristics as cryptographic keys. We will show why some current authentification schemes are insufficient and we will present our concepts of biometric hashes and auth...

An interesting type of objects in the SQL standard and database systems are triggers which are nowadays being widely used. The capability of automatic reaction to certain events is of great importance. Although the idea of triggers seems very promising, their complexity and variety of different programming languages used for their implementation hi...

For more than 20 years relational model is the most important database model. So, it is examined in the most various ways. A very important concept in the relational model is the concept of dependencies, especially functional dependencies. It is proven that functional dependencies can be represented by formulae of prepositional or predicate calculu...

The concept of triggers has been used for almost thirty years. But taking into account the fact that the active database theory kept developing during the years, it is even more and more obvious that existing database management systems do not keep the pace with the theory i.e. there is an obvious gap between the theory and the practice. The paper...

In this paper we present a modified neural network architecture and an algorithm that enables neural networks to learn vectors in accordance to user designed sequences or graph structures. This enables us to use the modified network algorithm to identify, generate or complete specified patterns that are learned in the training phase. The algorithm...

This paper describes an algorithm for an equal distribution of m identical elements on one-dimensional field of size n with m < n. During the development of the discrete event simulation of MANET (Mobile Ad Hoc Network), the need for equal distribution of special node roles (e.g. servers, clients or directories) on the nodes had occurred. The solut...

Multimedial Scripting Language of Higher Level (MMJS-from abbreviation of "Multimedijski jezik skripata više razine") is a new programming language. It's also a new multimedia technique, which tries to solve some problems with present technologies. MMJS is based on current trends in programming languages development, on development of multimedia sy...

The problem of the integration of heterogeneous data sources can be divided into two separated subproblems. The first one is the problem of solving semantic inconsistencies and conflicts between independent sources. This problem is treated in [4],[5],[6] and [12]. In this paper we shall deal with the second subproblem – the problem of the transl...

In some of our former papers ([5],[8] and [9]) we presented how to create intelligent agent based on modal logic. In some other our papers ([4] and [6]) the heterogeneous data sources integration system building was shown. This system can be used for implementation of one sort of multi-agent systems - multi-agent systems with supervisor. In this pa...

In the last few years modalities in a logic have a new dimension. They become very usefull in the artificial intelligence, and, what is the a special interest of this paper, in the knowledge representation. There are many ways to represent modalities in a formal logic, but one of the most common is through the modal logic. In the last time there ar...

The ncreasing number of data sources that are used for decision support in business meant it was necessary to integrate all sources and their unique representation to a user. The sources we may want to integrate can be internal (local databases, etc.) or external (Internet, etc.). Each one of these sources may have a different query language, wi...

In this article we are using logic-based language HiLog to integrate heterogeneous data sources. HiLog is Prolog type logic-based language with higher order syntax and fi�rst order semantic. In order to make HiLog more appropriate for processing uncertain data, we shall introduce a syntax extension of HiLog - annotations. Annotations are a well-kno...

A general context for the problem of decomposition within an information system is described. The problem has been classified as a NP-complete problem, which excludes the possibility of an optimal solution of the problem in polynomial time. This paper has two goals: first, to solve the problem within some additional limitations that are usual in...

At developing larger information systems, it is necessary to decompose them into subsystems for the purposes of easier designing. The intention is, in turn, for the decomposition to be performed in a way which results in as small losses in the system quality as possible. There is, therefore, a need of defining the system decomposition quality p...