The research proposed in this article presents a novel improved version of the widely adopted firefly algorithm and its application for tuning and optimising XGBoost classifier hyper-parameters for network intrusion detection. One of the greatest issues in the domain of network intrusion detection systems are relatively high false positives and false negatives rates. In the proposed study, by using XGBoost classifier optimised with improved firefly algorithm, this challenge is addressed. Based on the established practice from the modern literature, the proposed improved firefly algorithm was first validated on 28 well-known CEC2013 benchmark instances a comparative analysis with the original firefly algorithm and other state-of-the-art metaheuristics was conducted. Afterwards, the devised method was adopted and tested for XGBoost hyper-parameters optimisation and the tuned classifier was tested on the widely used benchmarking NSL-KDD dataset and more recent USNW-NB15 dataset for network intrusion detection. Obtained experimental results prove that the proposed metaheuristics has significant potential in tackling machine learning hyper-parameters optimisation challenge and that it can be used for improving classification accuracy and average precision of network intrusion detection systems.

Abstract:In order to keep pace with the ongoing changes in ICT and increasing common IT competencies requirements, informatics curricula at secondary school level and, consequently, curricula educating informatics teachers must be frequently changed to ensure necessary competencies. This paper proposes collaborative development of informatics curricula assisted by a software tool for compatibility analysis of secondary school informatics curricula and curricula by which teachers of informatics are educated. The proposed software tool relies upon semantic technologies, i.e. ontologies for representation of competence-based curricula and ontology alignment for compatibility analysis. The secondary school informatics curriculum ontology was built to comply with the ACM K12 standard, while the teachers' curriculum ontology was built based on the selected existing curricula. The paper presents a brief description of the software tool and the results of the domain (informatics) segment of teachers' curriculum offered by the selected Serbian university and the standardized ACM K12 compliant secondary school informatics curriculum.

There is a growing interest in the study development of artificial intelligence and machine learning, especially regarding the support vector machine pattern classification method. This study proposes an enhanced implementation of the well-known whale optimisation algorithm, which combines chaotic and opposition-based learning strategies, which is adopted for hyper-parameter optimisation and feature selection machine learning challenges. The whale optimisation algorithm is a relatively recent addition to the group of swarm intelligence algorithms commonly used for optimisation. The Proposed improved whale optimisation algorithm was first tested for standard unconstrained CEC2017 benchmark suite and it was later adapted for simultaneous feature selection and support vector machine hyper-parameter tuning and validated for medical diagnostics by using breast cancer, diabetes, and erythemato-squamous dataset. The performance of the proposed model is compared with multiple competitive support vector machine models boosted with other metaheuristics, including another improved whale optimisation approach, particle swarm optimisation algorithm, bacterial foraging optimisation algorithms, and genetic algorithms. Results of the simulation show that the proposed model outperforms other competitors concerning the performance of classification and the selected subset feature size.

Abstract:The aim of this paper is to clarify the significance of using responsive logos on web pages. It aims to bring a more flexible and contextual system of brand identification. This can be done by moving away from strict and inflexible design guidelines. The authors shall attempt to explain why logos in all its variations can be unambiguous memory hooks. Also, we emphasise that they can behave like many other elements in responsive web pages. Contemporary businesses demand adaptation of their content to many sophisticated communication platforms. Among these are the devices with different varying screen dimensions. A responsive logo can be used to build better user experiences across a wide range of devices, thus elevating brand freshness. Having in mind that logos are the key elements of corporate identity and brand positioning, it is mandatory to optimise it for every scenario. It is an element on par with colours or slogans. It can be simplified by applying responsive design principles to individual elements that make out the logo. By removing unnecessary parts in relation to the varying screen size, a clearer and much more readable logo can be arranged. We have built a model for applying responsive design to logos and performed experimental testing in the real environment.

This paper presents an implementation of a location-based service developed for smartphone devices. It also covers a review of the need for location-based services and methods of location acquisition, which include GPS, cell-stations, wireless access point and IP address based Geo-location lookup positioning. The paper covers a review of contemporary technologies for development of software systems based on the location-based services and their use on smartphone devices. The paper presents the implementation of a GIS designed to provide venue information based on the location information of smartphones with Android operating system. Apstrakt: U radu je predstavljena primena usluge bazirane na lokaciji, kreirane za pametne telefone. U njemu se analizira potreba za uslugama baziranim na lokaciji, kao i metode utvrđivanja lokacije, među kojima su GPS, lociranje pomoću baznih stanica, bežičnih mreža i utvrđivanje lokacije pomoću IP adrese. Rad sadrži i pregled savremenih tehnologija za izradu softverskih sistema baziranih na lokaciji i njihovu upotrebu na pametnim telefonima. Predstavljena je implementacija jednog geografskog informacionog sistema dizajniranog da pruži informacije o ugostiteljskim objektima, koje su u blizini pametnih uređaja sa Android operativnim sistemom, bazirane na njihovoj lokaciji.

In this paper we present a proposed multi-layered image format for use on the web. The format implements an algorithm for selecting adequate layer images depending on the image container's surroundings and size. The layer selection depends on the weighted average brightness of the underlying web page background within the bounds of the image. The proposed image format supports multiple image layers with adjoined thresholds and activation conditions. Depending on these conditions and the underlying background, a layer's visibility will be adequately set. The selection algorithm takes into account the background brightness, each layer's adjoined threshold values, and other newly introduced layer conditions.

Computational methods are, among other things, widely used in operational research. Operational research is a complex interdisciplinary field that deals with the problems of decision-making in real conditions, considering all the factors that affect the problem directly or indirectly, in order to find the best, i.e. optimal solution. As there is a growing need for continuous process improvement, there is a growing presence of operational research methods for various real-life problems. The transportation problem is one of the segments of research within operational research. It aims to determine the optimal program of distribution of a certain type of commodity from sources (points of origin) to destinations. The sources are the places where the commodity leaves (the warehouse), while the destinations are the ending points to which the commodity should be transported (in our case -the store). As a criterion for optimizing the transportation of goods, the request for minimizing the total transportation costs is most often taken. In the case of transportation problem, the objective function expresses the total transportation costs, while the limiting conditions are determined by the supply of individual sources (warehouses), i.e. the demand of individual destinations (stores). This paper discusses the possibility of applying operational research methods in the service sector. The aim of the research part of the paper is to find the optimal solution for real data of a given problem, simulating different conditions and constraints. An experimental analysis was performed for the problem of warehouse operations, and the goal was to minimize the costs of transporting goods. Two different methods were applied in order to determine the optimal solution. Based on the obtained results and their analysis, conclusions were made as to whether the problem was solved.

This work analyses the impact of the server operating system on the overall performance of hosted web sites. In the paper, we are presenting the results of comparing the influence of the two most common server operating system families, Windows and the GNU/Linux distributions. Through experiments, we have collected data based on which we have concluded the impact of these operating systems on the performance of a web site developed using the most commonly used web platform -WordPress. The experiment was set up in such a way as to eliminate the impact of hardware on our measurements, which is done by using the same hardware, network and matching conditions. The experiment was conducted with a large number of repetitions to reduce relative errors in measurements. The performance analysis covers files of different sizes and types, including text and multimedia content typical for modern web sites.