rss_2.0Computer Sciences FeedSciendo RSS Feed for Computer Scienceshttps://www.sciendo.com/subject/COhttps://www.sciendo.comComputer Sciences Feedhttps://www.sciendo.com/subjectImages/Computer_Sciences.jpg700700Adoption of big data technologies in smart cities of the European Union: Analysis of the importance and performance of technological factorshttps://sciendo.com/article/10.2478/crdj-2021-0005<abstract> <title style='display:none'>Abstract</title> <p>The cities of the European Union are adopting big data technologies in their development towards a smart city. Given that big data technologies are complex and disruptive technologies, it is necessary to determine the importance of factors and their aspects for the adoption of big data technologies in cities. The aim of this paper is to identify the most important aspects of technological factors in the adoption of big data technologies in the cities of the European Union. In order to achieve the goal of the paper a survey was conducted on a sample of European Union cities, and on the collected data, an analysis of the map of importance and performance of factors for the adoption of big data technologies was conducted. The results of the research show that the aspects of absorption capacity and technological readiness of EU cities are of relatively high importance, but with low levels of performance in relation to organizational and environmental factors. The contribution of the paper consists of general guidelines for increasing the level of technological readiness and absorption capacity of cities in order to increase the success of the adoption of big data technologies in the cities of the European Union.</p> </abstract>ARTICLE2021-09-13T00:00:00.000+00:00Frost resistance of cement-sand and concrete beams during unilateral freezinghttps://sciendo.com/article/10.2478/crdj-2021-0009<abstract> <title style='display:none'>Abstract</title> <p>The work investigates changes in the beam structure under the action of local freezing, which leads to a change of the mechanical properties of the material and, consequently, of the beam structure. Two types of beam samples were used: from cement-sand mortar and from concrete. The work investigates the change in the development of deformations depending on the conditions of freezing of samples. The second accelerated method for assessing frost resistance was chosen according to DSTU B В.2.7-47-96. An accelerated method was chosen for assessing frost resistance at the temperature of -20 ±2 C°. After every five freeze-thaw cycles, the following changes were monitored: mass, water absorption, ultrasound transmission rate, damage coefficient, tensile bending strength, splitting strength, compressive strength, carbonization depth. The results showed that both in concrete and in mortar samples, the compressive strength after freezing was lower by 8% and 15% accordingly. The experimental results obtained confirm the assumptions made that the frost resistance of the material depends on the conditions of exposure of negative temperatures on products and structures and it can be used in a wider range of construction which will push regional development.</p> </abstract>ARTICLE2021-09-13T00:00:00.000+00:00Fine-grained Fiber Concrete on Mechanoactivated Portlandcementhttps://sciendo.com/article/10.2478/crdj-2021-0007<abstract> <title style='display:none'>Abstract</title> <p>This article is devoted to the study of the mechanical properties of fine-grained concrete used for flooring in industrial and civil buildings. Characterized by the well-known advantages (unlimited raw material base, manufacturability, high homogeneity), fine-grained concrete requires an increased consumption of cement to achieve the necessary mechanical characteristics - compressive strength, abrasion, impact resistance. An alternative to the known technological method is proposed an intensive separate technology (IST) for preparing fine-grained concrete mixtures using a high-speed mixer-activator in the presence of hydrophobized basalt fiber and a polycarboxylate superplasticizer Relaxol-Super PC. The use of IST leads to an increase in the strength of fine-grained concrete in compression by 1.9 times, impact resistance by a factor of 2, and a decrease in abrasion by 40... 50% in comparison with the control. The relevance of using the technology of monolithic floors for industrial and civil construction is due to a wide range of varieties of Portland cement, the grain composition of aggregates, as well as the simplicity of the technology for preparing a fine-grained concrete mixture.</p> </abstract>ARTICLE2021-09-13T00:00:00.000+00:00European Cohesion Policy and Evaluating the Impact of Evidence-Based Policyhttps://sciendo.com/article/10.2478/crdj-2021-0008<abstract> <title style='display:none'>Abstract</title> <p>In the 2014–2020 programming period, the cohesion policy focuses more on results and evaluation of programs based on facts. Due to the Commission policies, an expansion of cohesion policy counterfactual impact evaluation of programmes with new approaches can be expected in the future. In this paper, the focus is on the calculation of the impact of received European cohesion funds on the revenue of companies in Slovenian municipalities one/two years after the receipt of cohesion funds for the 2007–2013 period. Two development priorities that affect company revenue – Enterprise competitiveness and research excellence and Promoting entrepreneurship and adaptability are considered. The effect of the use of the European cohesion funds on company revenue in Slovenian municipalities is positive for 2009 and 2010 and negative for all other years examined. The results of the research can serve to policy-makers to reduce the economic, social and territorial disparities in less developed European countries and regions therefore reaching balanced regional development.</p> </abstract>ARTICLE2021-09-13T00:00:00.000+00:00Rethinking niche tourism: The example of backpackinghttps://sciendo.com/article/10.2478/crdj-2021-0004<abstract> <title style='display:none'>Abstract</title> <p>This conceptual paper re-evaluates the concept of niches in tourism markets. As many regions are now attempting to address niche markets in tourism as a development strategy, understanding of the dynamics of niche markets is crucial. Current approaches are often limited to seeing niche markets as simple subsectors of larger consumer markets. We argue for a broader view of market niches as forms of social rituals involving both consumers and producers with a mutual focus of attention. Based on the work of Randall Collins we examine how interaction rituals are produced and maintained, and how these are also reflected in niche markets, such as backpacking. We illustrate the how backpacking produces a mutual focus of attention and boundaries to outsiders, helping to sustain the niche over the longer term. This analysis has implications for producers hoping to tap into niche markets, as they too need to become part of the niche community.</p> </abstract>ARTICLE2021-09-13T00:00:00.000+00:00Durability of Modified Fiber Concrete for Rigid Pavementshttps://sciendo.com/article/10.2478/crdj-2021-0006<abstract> <title style='display:none'>Abstract</title> <p>Modified concretes and fiber concretes for rigid pavements have been investigated. Four-factor experiment was conducted. The amount of Portland cement, polypropylene fiber, metakaolin and polycarboxylate superplasticizer varied in the experiment. All mixtures had the same mobility S2.</p> <p>The active mineral additive metakaolin increases the compressive strength of concrete and its tensile strength in bending. The amount of metakaolin at the level of 15.20 kg/m<sup>3</sup> is rational. Due to a decrease in W/C with an increase in the amount of superplasticizer Coral ExpertSuid-5 to 0.9.1%, the compressive strength of concrete increases by 5.7 MPa, the tensile strength in bending increases by 0.5.0.6 MPa. Due to the introduction of polypropylene fiber, the tensile strength of concrete in bending increases by 0.6.0.9 MPa, the frost resistance of concrete increases by 50 cycles. Due to the use of a rational amount of superplasticizer and metakaolin, the frost resistance of concretes and fiber concretes concrete increases by 50-100 cycles. The use of a rational amount of modifiers and fiber reduces the abrasion of concretes by 40.45%.</p> <p>The developed modified fiber concretes of rigid pavements, depending on the amount of Portland cement, have compressive strength from 55 MPa to 70 MPa, tensile strength in bending from 8 MPa to 9.5 MPa, frost resistance from F350 to F450, abrasion from 0.30 to 0.40 g/cm<sup>2</sup>. Such strength, frost resistance and abrasion resistance allow the use of fiber concretes in pavements with the greatest load and ensures high durability of the material and corresponds to the directions and tasks of the state scientific and technical program “National Transport Strategy of Ukraine for the period up to 2030”</p> </abstract>ARTICLE2021-09-13T00:00:00.000+00:00Expert Survey on Current Trends in Agile, Disciplined and Hybrid Practices for Software Developmenthttps://sciendo.com/article/10.2478/acss-2021-0005<abstract> <title style='display:none'>Abstract</title> <p>Every software development company makes software development based on a specific approach. There are a number of approaches to software development, both disciplined and agile. Each approach includes a set of different activities. Sometimes, the specific nature of a company’s work requires a specific approach, but the need to make work more efficient, faster and better requires implementing activities of other approaches. Then hybrid software development approaches come in. The paper presents an expert survey to examine the most important software development activities, the combinations of development approaches that are used in software development processes and the way of upgrading existing approaches. The evaluated activities of software development process are classified according to their nature – whether they correspond with a team, organisation, documentation, development, and testing. The conclusions are also made on the practices that are required most – disciplined, Agile or hybrid.</p> </abstract>ARTICLE2021-06-04T00:00:00.000+00:00Mapping of Source and Target Data for Application to Machine Learning Driven Discovery of IS Usability Problemshttps://sciendo.com/article/10.2478/acss-2021-0003<abstract> <title style='display:none'>Abstract</title> <p>Improving IS (Information System) end-user experience is one of the most important tasks in the analysis of end-users behaviour, evaluation and identification of its improvement potential. However, the application of Machine Learning methods for the UX (User Experience) usability and effic iency improvement is not widely researched. In the context of the usability analysis, the information about behaviour of end-users could be used as an input, while in the output data the focus should be made on non-trivial or difficult attention-grabbing events and scenarios. The goal of this paper is to identify which data potentially can serve as an input for Machine Learning methods (and accordingly graph theory, transformation methods, etc.), to define dependency between these data and desired output, which can help to apply Machine Learning / graph algorithms to user activity records.</p> </abstract>ARTICLE2021-06-04T00:00:00.000+00:00Real-Time Turkish Sign Language Recognition Using Cascade Voting Approach with Handcrafted Featureshttps://sciendo.com/article/10.2478/acss-2021-0002<abstract> <title style='display:none'>Abstract</title> <p>In this study, a machine learning-based system, which recognises the Turkish sign language person-independent in real-time, was developed. A leap motion sensor was used to obtain raw data from individuals. Then, handcraft features were extracted by using Euclidean distance on the raw data. Handcraft features include finger-to-finger, finger -to-palm, finger -to-wrist bone, palm-to-palm and wrist-to-wrist distances. LR, <italic>k</italic>-NN, RF, DNN, ANN single classifiers were trained using the handcraft features. Cascade voting approach was applied with two-step voting. The first voting was applied for each classifier’s final prediction. Then, the second voting, which voted the prediction of all classifiers at the final decision stage, was applied to improve the performance of the proposed system. The proposed system was tested in real-time by an individual whose hand data were not involved in the training dataset. According to the results, the proposed system presents 100 % value of accuracy in the classification of one hand letters. Besides, the recognition accuracy ratio of the system is 100 % on the two hands letters, except “J” and “H” letters. The recognition accuracy rates were 80 % and 90 %, respectively for “J” and “H” letters. Overall, the cascade voting approach presented a high average classification performance with 98.97 % value of accuracy. The proposed system enables Turkish sign language recognition with high accuracy rates in real time.</p> </abstract>ARTICLE2021-06-04T00:00:00.000+00:00VP-RDF: An RDF Based Framework to Introduce the Viewpoint in the Description of Resourceshttps://sciendo.com/article/10.2478/acss-2021-0006<abstract> <title style='display:none'>Abstract</title> <p>The description of resources and their relationships is an essential task on the web. Generally, the web users do not share the same interests and viewpoints. Each user wants that the web provides data and information according to their interests and specialty. The existing query languages, which allow querying data on the web, cannot take into consideration the viewpoint of the user. We propose introducing the viewpoint in the description of the resources. The Resource Description Framework (RDF) represents a common framework to share data and describe resources. In this study, we aim at introducing the notion of the viewpoint in the RDF. Therefore, we propose a View-Point Resource Description Framework (VP-RDF) as an extension of RDF by adding new elements. The existing query languages (e.g., SPARQL) can query the VP-RDF graphs and provide the user with data and information according to their interests and specialty. Therefore, VP-RDF can be useful in intelligent systems on the web.</p> </abstract>ARTICLE2021-06-04T00:00:00.000+00:00Evaluating the Impact of Design Pattern Usage on Energy Consumption of Applications for Mobile Platformhttps://sciendo.com/article/10.2478/acss-2021-0001<abstract> <title style='display:none'>Abstract</title> <p>Energy efficiency in mobile computing is really an important issue these days. Owing to the popularity and prevalence of Android operating system among the people, a great number of Android smartphone applications have been developed and proliferated by the software developers. While developing these applications, developers have to keep energy consumption factor in mind, as the efficiency of an application is largely affected by it. Thus, designers and programmers endeavour to choose the best designing approaches to develop energy-efficient applications. It is imperative to assist the programmers in choosing appropriate techniques and strategies to manage power consumption. In the present research, we have investigated the effect of Android application design on its energy utilisation. For this purpose, we have practically implemented design patterns on two Android applications and evaluated their energy consumption before and after implementing these patterns. We have modelled the high-level design of these two Android applications by using software design patterns in such a way as to abate their energy requirement. We have also checked how the quality, maintainability, and efficiency of code are affected by these design patterns. The outcomes of the research can facilitate programmers to utilise these details while developing energy efficient solutions.</p> </abstract>ARTICLE2021-06-04T00:00:00.000+00:00Time Series Smoothing Improving Forecastinghttps://sciendo.com/article/10.2478/acss-2021-0008<abstract> <title style='display:none'>Abstract</title> <p>Both statistical and neural network methods may fail in forecasting time series even operating on a great amount of data. It is an open question of which amount fits best to make sufficiently accurate forecasts on it. This implies that the length or time series might be optimised. Hence, the objective is to improve the quality of forecasting by an assumption that parameters are set nearly at their optimal values. To achieve objective, the two types of the benchmark time series are considered: sine-shaped series and random-like series with repeatability. Trend, seasonality, and decay properties embedded into each type. Based on the benchmark of 24 time series models, it is ascertained that, for improving the forecasting, the time series should be smoothed and then downsampled. These operations can be fulfilled successively until the improvement fails. If preliminary smoothing worsens forecasts, the raw time series is straightforwardly downsampled until the forecasting accuracy starts dropping. However, if time series has a visible property of being noised, the preliminary smoothing is strongly recommended.</p> </abstract>ARTICLE2021-06-04T00:00:00.000+00:00Solving Systems of Linear Equations Based on Approximation Solution Projection Analysishttps://sciendo.com/article/10.2478/acss-2021-0007<abstract> <title style='display:none'>Abstract</title> <p>The paper considers an iterative method for solving systems of linear equations (SLE), which applies multiple displacement of the approximation solution point in the direction of the final solution, simultaneously reducing the entire residual of the system of equations. The method reduces the requirements for the matrix of SLE. The following SLE property is used: the point is located farther from the system solution result compared to the point projection onto the equation. Developing the approach, the main emphasis is made on reduction of requirements towards the matrix of the system of equations, allowing for higher volume of calculations.</p> </abstract>ARTICLE2021-06-04T00:00:00.000+00:00The Impact of Note-Taking on the Learning Process in Intelligent Tutoring System Tutomathttps://sciendo.com/article/10.2478/acss-2021-0004<abstract> <title style='display:none'>Abstract</title> <p>The research investigates how note-taking practice affects the learning process in Tutomat, an intelligent tutoring system. The complete analysis includes (i) the identification of learning analytics variables to describe student-Tutomat interaction; (ii) the description of experimental student groups using learning analytics variables; (iii) data-driven clustering and (iv) the comparison of the experimental groups and revealed clusters. The results show that there is a difference in how a student interacts with Tutomat based on note-taking practice. It is revealed that the note-taking practice can be detected using the proposed learning analytics variables with the prediction accuracy of the clustering approach of 85 %.</p> </abstract>ARTICLE2021-06-04T00:00:00.000+00:00Increasing fault tolerance in service-level agreement constrained context-aware data networkshttps://sciendo.com/article/10.2478/cjece-2020-0009<abstract><title style='display:none'>Abstract</title><p>Attribute study and analysis of fault tolerant data networks. This work is aimed at introducing SLA constrain into fault tolerance and thus increasing overall network availability. Proposed model will evaluate given constraints and select best path that fits requirements. Fault tolerance is increased by adding multiple constraints and thus reducing available paths to best fitting ones.</p></abstract>ARTICLE2020-12-31T00:00:00.000+00:00Using Pathological Elements in Analog Circuit Analysis and Simulationhttps://sciendo.com/article/10.2478/cjece-2020-0006<abstract><title style='display:none'>Abstract</title><p>This paper is focused on some kind of mystery circuit nullator, nullor, current mirror, and voltage mirror, all of them known as pathological elements. These pathological elements can be used to perform circuit modelling, symbolic circuit analysis, circuit synthesis, circuit design and to develop applications that involve modern active devices. It is described a new modeling of nullor-based active devices from the circuit abstraction level. In this paper it is presented the way all types of equations which describe the circuit containing nullors can be directly formulated from the diagrams of these circuits if we took into account that a nullator is an over-determined two-port circuit element (zero voltage, zero current) and the norator is an undetermined two-port circuit element (any voltage and any current). To simulate the nullors with ideal voltage controlled voltage sources, ec = Ac_c uc, with the control gate an ideal independent current source, jC = 0.0 A and with the amplification (transfer) factor Ac_C very big (theoretically ∞), the analog circuits with nullors can be analyzed by using any of the existing simulation software. By this way, it was possible the elaboration of efficient algorithms for an automatic formulation of Kirchhoff’s equations, of loop equations, of modified nodal equations and of state equations for circuits with pathological elements. These procedures can be easily implemented in dedicated programs for the simulations of the complex analog circuits with pathological elements. The example presented in this paper validates the presented models for nullors.</p></abstract>ARTICLE2020-12-31T00:00:00.000+00:00A Survey about Intelligent Solutions for Autonomous Vehicles based on FPGAhttps://sciendo.com/article/10.2478/cjece-2020-0007<abstract><title style='display:none'>Abstract</title><p>Safe driving and reducing the number of accidents victims have been the main motivations for researchers and automotive companies for decades. Today, humanity is very close to make the old dream of fully autonomous vehicles a reality, thanks to the rapid spread of AI (artificial intelligence) and the evolution of semiconductor technologies. But the real problem here is the increasing demand for computational power and that of course will increase power requirements, hence it will not be suitable for autonomous driving applications. GPU is not suitable for solving this problem due to its power consumption as well as heat generation. On the other hand, CPU also does not satisfy the performance requirements. For the above condition, FPGA (Field Programmable Gate Array) has drawn attention as a hardware accelerator since it features high performance with low power consumption. This paper reviews the common solutions involving artificial intelligence implemented on FPGA for autonomous vehicle applications. Research, development, and current trends related to the topic are emphasized.</p></abstract>ARTICLE2020-12-31T00:00:00.000+00:00Theoretical and experimental aspects of the controlled movement of solenoid actuators by means of the voltage static converter with logic gateshttps://sciendo.com/article/10.2478/cjece-2020-0010<abstract><title style='display:none'>Abstract</title><p>The purpose of the scientific research in this paper is to control the movement of electromechanical actuators, through a new voltage convertor. The optimization of the system consists in finding new solutions to control the movement of electromechanical actuators in the gas valve, used in thermal power plants, which can be operated by static converters - with logic gates.</p></abstract>ARTICLE2020-12-31T00:00:00.000+00:00Pragmatic Implementation of the Front-End of an N-bit/V ADC based on FPGA and FPAAhttps://sciendo.com/article/10.2478/cjece-2020-0008<abstract><title style='display:none'>Abstract</title><p>Reconfigurability has made it possible, among other benefits, to replace traditional discrete components with chips, whose internal components can be programmed in this case FPAAs (Field Programmable Analog Arrays). This paper presents a design and implementation of FPAA of the analog front end dedicated to a new ADC architecture called “N-bit/V”. After validation of the algorithm in simulation, the experimentation results show that the obtained reconfigurable circuit can replace the traditional discrete components-based circuits.</p></abstract>ARTICLE2020-12-31T00:00:00.000+00:00Towards autoscaling of Apache Flink jobshttps://sciendo.com/article/10.2478/ausi-2021-0003<abstract> <title style='display:none'>Abstract</title> <p>Data stream processing has been gaining attention in the past decade. Apache Flink is an open-source distributed stream processing engine that is able to process a large amount of data in real time with low latency. Computations are distributed among a cluster of nodes. Currently, provisioning the appropriate amount of cloud resources must be done manually ahead of time. A dynamically varying workload may exceed the capacity of the cluster, or leave resources underutilized. In our paper, we describe an architecture that enables the automatic scaling of Flink jobs on Kubernetes based on custom metrics, and describe a simple scaling policy. We also measure the e ects of state size and target parallelism on the duration of the scaling operation, which must be considered when designing an autoscaling policy, so that the Flink job respects a Service Level Agreement.</p> </abstract>ARTICLE2021-07-08T00:00:00.000+00:00en-us-1