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In this paper is presented the study on Hall current sensors for differential current measurement, aiming to be used in a smart protection device for leakage current in low voltage lines. Experiments have highlighted solutions but also various deficiencies. The paper also proposes measures to enhance measurement errors.
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Adoption of agile methods in the software development organization is considered as a powerful solution to deal with the quickly changing and regularly developing business environment and fully-educated customers with constantly rising expectation, such as shorter time periods and an extraordinary level of response and service. This study investigates the adoption of agile approaches in software development organizations by using systematic mapping. Six research questions are identified, and to answer these questions a number of research papers have been reviewed in electronic databases. Finally, 25 research papers are examined and answers to all research questions are provided.
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The authors are proposed to do impact of sustainability through separate business model elements focusing on managing human resources in the enterprise. The great significance of human recourses in the enterprise is determined by the need for continuous changes that directly affect people - a source of ideas and a core resource. Here are offered two methodologies- to increase the level of creativity and to increase adaptivity for changes which are two elements from technology entrepreneurship business model proposed for Bulgarian technology-based entrepreneurial firms.
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Using online discussion forums and peer-to peer interactive learning currently becomes a common instructional proposition. Such social discourse is educationally adopted to enhance learning and through ideas interchanged in an online setting. The aim of this study was to investigate the use of LINE as an instructional tool complementing language practice to express opinions in an EFL course. In order to examine factors related to student learning performance in the online discussion activity, data were collected from learning score, quantity of interaction, as well as attitude from 83 students. Frequency, mean, and correlation coefficients were employed to analyze. The findings revealed students’ positive attitude toward the online activity, with the highest mean score indicating an enjoyable learning environment. The students’ learning outcome showed positive correlation with frequency of their interaction; however, it was disassociated with their attitude toward the assigned online task. Furthermore, students’ engagement in the learning disclosed no relation with their attitude toward the online educational experience. The finding of the study can be beneficial for online activity course designs in the future. Apparently, student participation is considered a vital variable; thus, motivation strategies are to be carefully planned to facilitate effective online learning.
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The paper describes and interprets differences among social network structures in the private sector, politics (local administration) and non-governmental organisations (NGO) in Croatia. Social network analysis (SNA) methodology was used to examine networks in three sectors, which were found to differ in terms of centrality measures and substructures. In the private sector network, centrality values of network members were related to their respective positions in the organisational hierarchy. In the politics network, centrality measures values of members were influenced both by hierarchy and by the number of same-party members. In the NGO network, all members had high centrality values. Substructure sizes were low in the private sector and high in the NGO sector; in the politics network, they were dependent on the number of same-party members.
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The usage of new information and communication technology and systems [1] in the modern society enables easier access to a growing number of services, tools and devices that in the present day are more available to the public than ever before and can be found in every social circle. This article concentrates on the usage of new information and communication technologies and TV among children from seven to ten years of life. The lack of movement and a sedentary lifestyle accompanied by the often usage of devices available to them may lead towards certain disorders among younger children (dyslexia, dysgraphia, dyscalculia, growing number of children with flat feet), especially among children starting the first grade of elementary schools. This article shows a part of research conducted on a representative sample of 1286 subjects in Croatia, Italy and Serbia. In accordance with the needs of this article, the presented results were obtained by analyzing the following variables: time spent in front of the TV and computer daily and during the weekends, ownership of a smartphone, if the rules of the usage of a smartphone are set beforehand by parents/guardians/caretakers, usage of smartphones for accessing on-line video games and if the subjects use smartphones in class without the awareness of teachers and for their personal needs that don’t involve the class program. The article presents the results of the application of the NTC learning program which can help in solving the big issue of the urgent need to change the educational system.
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In this paper we consider the application of dynamic programming in bioinformatics for comparing and aligning DNA sequences. Dynamic programming algorithms are old-fashioned in terms of computational complexity, but in terms of accuracy these algorithms are still irreplaceable.
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Nowadays we see an increase of interest in immersive technologies connected with new modes of communication. With novel devices possibilities open for research in the field of Human-Computer Interfaces(HCI) and Virtual Reality (VR). This project is focused on the creation of interactive virtual reality scenery and on the verification of usefulness of different interfaces in such contexts. We designed a virtual urban space that is accessible to users through VR goggles: Oculus Rift paired with Leap Motion. We prepared an experiment to test how well users can interact in proposed virtual environment through this setup. Results show that in simple tasks users can quickly learn on their own how to use given interface without tutoring.
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The paper surveys methods and approaches for the task of keyword extraction. The systematic review of methods was gathered which resulted in a comprehensive review of existing approaches. Work related to keyword extraction is elaborated for supervised and unsupervised methods, with a special emphasis on graph-based methods. Various graph-based methods are analyzed and compared. The paper provides guidelines for future research plans and encourages the development of new graph-based approaches for keyword extraction.
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In recent years, the use of public procurement as a tool for promoting innovation has captured the interest of many researchers. However, their research mostly focuses on the impact of public procurement on companies’ innovativeness. This article discusses the findings of available literature on this topic and proposes a model of transferring the concept from a company level to the level of the whole country. One of the major problems is the unavailability of appropriate measures for this phenomenon, so the authors of this paper suggest that the concept of public procurement for innovation can be approximated by applying the most economically advantageous tender (MEAT) criterion. The implementation of this criterion in choosing the best offer can be supported and facilitated by the use of ICT, which can improve the efficiency of procurement process and enable more innovations.
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Utilization of expert effort estimation approach shows promising results when it is applied to software development process. It is based on judgment and decision making process and due to comparative advantages extensively used especially in situations when classic models cannot be accounted for. This becomes even more accentuated in today’s highly dynamical project environment. Confronted with these facts companies are placing ever greater focus on their employees, specifically on their competences. Competences are defined as knowledge, skills and abilities required to perform job assignments. During effort estimation process different underlying expert competences influence the outcome i.e. judgments they express. Special problem here is the elicitation, from an input collection, of those competences that are responsible for accurate estimates. Based on these findings different measures can be taken to enhance estimation process. The approach used in study presented in this paper was targeted at elicitation of expert estimator competences responsible for production of accurate estimates. Based on individual competences scores resulting from performed modeling experts were ranked using weighted scoring method and their performance evaluated. Results confirm that experts with higher scores in competences identified by applied models in general exhibit higher accuracy during estimation process. For the purpose of modeling data mining methods were used, specifically the multilayer perceptron neural network and the classification and regression decision tree algorithms. Among other, applied methods are suitable for the purpose of elicitation as in a sense they mimic the ways human brains operate. Data used in the study was collected from real projects in the company specialized for development of IT solutions in telecom domain. The proposed model, applied methodology for elicitation of expert competences and obtained results give evidence that in future such a model can be used in practice to reduce estimation error and enhance expert effort estimation.
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The article deals with methods of solving the problem of ranging of alternatives in information-analytical system of managing the quality of telecommunication services rendering process. Tasks of choice are determined, in which the alternatives are as follows: states of quality of different objects in the structure of telecommunication company management. An algorithm of ranging of objects is elaborated for the case of using unstructured set of indices. The algorithm enables to determine the objects priorities and to select the best ones among them. The suggested methods may be used while elaborating the programs of improvement of telecommunication companies competitiveness.
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A method of constructing boosting ensembles of heavy two-layer perceptrons is stated. The benchmark classification problem is recognition of shifted-turned-scaled flat images of a medium format with binary features. The boosting gain is suggested in two aspects. The earliest one is the ratio of minimal recognition error percentage among the ensemble perceptrons to the recognition error percentage performed by the ensemble. The second gain type is the ratio of minimal variance of perceptrons’ recognition error percentages over 26 classes to variance of the ensemble’s recognition error percentages over 26 classes. Both ratios increase as the number of perceptron classifiers in the ensemble increase. The ensemble of 36 classifiers performs with increased accuracy, where recognition error percentage is decreased for 33 %, and the variance is decreased for more than 50 %. Further increment of classifiers into ensemble cannot increase accuracy much as there is the saturation effect of the boosting gain. And the gain itself depends on the range of noise modeling object’s distortions. Thus, the heavier perceptron classifier the less gain is expected.
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Search engine optimization (SEO) techniques involve „on-page“ and „off-page“ actions taken by web developers and SEO specialists with aim to increase the ranking of web pages in search engine results pages (SERP) by following recommendations from major search engine companies. In this paper we explore the possibility of creating a metric for evaluating on-page SEO of a website. A novel „k-rank“ metric is proposed which takes into account not only the presence of certain tags in HTML of a page, but how those tags are used with selected keywords in selected domain. The „k-rank“ is tested in domain of education by inspecting 20 university websites and comparing them with expert scores. The overview of results showed that „k-rank“ can be used as a metric for on-page SEO.
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During the process of knowledge discovery in data, imbalanced learning data often emerges and presents a significant challenge for data mining methods. In this paper, we investigate the influence of class imbalanced data on the classification results of artificial intelligence methods, i.e. neural networks and support vector machine, and on the classification results of classical classification methods represented by RIPPER and the Naïve Bayes classifier. All experiments are conducted on 30 different imbalanced datasets obtained from KEEL (Knowledge Extraction based on Evolutionary Learning) repository. With the purpose of measuring the quality of classification, the accuracy and the area under ROC curve (AUC) measures are used. The results of the research indicate that the neural network and support vector machine show improvement of the AUC measure when applied to balanced data, but at the same time, they show the deterioration of results from the aspect of classification accuracy. RIPPER results are also similar, but the changes are of a smaller magnitude, while the results of the Naïve Bayes classifier show overall deterioration of results on balanced distributions. The number of instances in the presented highly imbalanced datasets has significant additional impact on the classification performances of the SVM classifier. The results have shown the potential of the SVM classifier for the ensemble creation on imbalanced datasets.
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This paper integrates theories and findings of the level of tertiary educated workforce, the human resources in science and technology and skills that are desirable in employees from in the information and communication technologies (ICT) sector. It is important to examine the real situation on the labor market in the ICT sector, which is often referred to as the key to overcoming the crisis and the future of national economy. Basic statistical elements, upon which to predict future demand for human resources in science and technology (HRST), are people who enter tertiary level of education (inputs) or are already in the system (throughputs), but until graduation are not considered HRST’s (outputs). Analysis is based on a sample of 56 small companies in ICT sector in Croatia. This paper presents the overview of the situations of human resources in small companies ICT sector in Croatia. Existing literature on HRST, employee’s skills and ICT sector is reviewed in the light of this analysis, in order to better understand current employment structure and desirable competencies of future employees of small companies in the ICT sector in Croatia.
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Distribution problems had held a large body of research and development covering the VRP problem and its multiple characteristics, but few investigations examine it as an Information System, and far fewer as how it should be addressed from a development and implementation point of view. This paper describes the characteristics of a real information system for fuel distribution problems at country scale, joining the VRP research and development work using Genetic Algorithms, with the design of a Web based Information System. In this paper a view of traditional workflow in this area is shown, with a new approximation in which is based proposed system. Taking into account all constraint in the field, the authors have developed a VRPWeb-based solution using Genetic Algorithms with multiple web frameworks for each architecture layer, focusing on functionality and usability, in order to minimizing human error and maximizing productivity. To achieve these goals, authors have use SmartGWT as a powerful Web based RIA SPA framework with java integration, and multiple server frameworks and OSS based solutions, applied to development of a very complex VRP system for a logistics operator of petroleum products.
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There is suggested a method of approximating unit-hypercubic infinite antagonistic game with the matrix game and the corresponding solution in finite strategies. The method is based on dimension-dependent irregular samplings over the game kernel. Numbers of the sampling points and their coordinates are chosen due to the stated conditions. If the sampled kernel is not the flat matrix them the multidimensional payoff matrix is reshaped into the flat one wherewith to solve the matrix game. The reshaping is a reversible matrix map. The concluding step of the approximation is in checking the finite solution consistency. Consistency can be weakened, and consistency can be checked at some rank corresponding to a natural number. The higher rank of the finite solution consistency is, the wider neighborhood of the sampling numbers at which the solution properties are monotonic-like.
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In the digital age, more and more artists are starting to present their works in an interactive way. Due to the rapid progression of the virtual environment and its attractiveness, it appears that new explorations of intuitive and user-friendly galleries are required. We created a draft of a computer application interface and then prepared a special gallery driven by different hand motions performed in mid-air. We conducted research of our proposed solution to compare these gestures and to find out how it is being perceived by people from outside the IT industry.
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In every boiler plant, including industrial boiler plants of thermal capacity above 2 MW, substantial heat gains are generated during the work of combustion units. As a result, the indoor air temperature raises in the room, which affects thermal comfort of workers operating such technological installations. Therefore, heat removal requires an effective mechanical ventilation system. A numerical analysis of the selected air parameters in a room equipped with combustion devices was undertaken using computational fluid dynamic (CFD) simulations in the DesignBuilder software. This was done for a combustion plant in the “Installation of Thermal Treatment of Sewage Sludge” building, located in the “Group Sewage Treatment Plant” complex of Lodz, Poland. The numerical analysis was based on experimental measurements and the results concerning the personnel work area were compared to the guidelines of the ISO international standard 7730:2005.
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