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Tomáš Mandičák, Peter Mesároš and Mária Kozlovská

Abstract

The issue of cloud computing is a highly topical issue. Cloud computing represents a new model for information technology (IT) services based on the exploitation of Web (it represents a cloud) and other application platforms, as well as software as a service. In general, the exploitation of cloud computing in construction project management has several advantages, as demonstrated by several research reports. Currently, research quantifying the exploitation of cloud computing in the Slovak construction industry has not yet been carried out. The article discusses the issue of exploitation of cloud computing in construction project management in Slovakia. The main objective of the research is to confirm whether factors such as size of construction enterprise, owner of construction enterprise and participant of construction project have any impact on the exploitation level of cloud computing in construction project management. It includes confirmation of differences in use between different participants of the construction project or between construction enterprises broken down by size and shareholders.

Open access

Mária Čarnogurská, Miroslav Příhoda and Tomáš Brestovič

Modelling of nitrogen oxides formation applying dimensional analysis

The article presents the procedure for how to establish a mathematical model of nitrogen oxides formation based on the theory of dimensional analysis. The model is based on selected physical quantities (parameters) measurable during regular operation of a heat generation plant. The objective of using dimensional analysis to describe nitrogen oxides formation is to show that between operating parameters of the combustion equipment and the NOx formation there is a significant correlation.

The obtained results, which are further described in this article, have proved this fact. The obtained formula expressing nitrogen oxides formation, based on dimensional analysis, applies universally to any boiler fuelled by coal, gas or biomass. However, it is necessary to find C, m, n constants for the formula by experiment, individually for each type of boiler and used fuel. The experiment is based on on-line measurements of selected operational parameters for a given boiler, combusting a certain type of fuel with its actual moisture content and calorific value. The methodology, described in this article, helps to find relationships between the operational parameters and the formation of NOx emissions for a particular furnace. The developed mathematical model has been validated with boilers fuelled by black coal and biomass. Both the results obtained from direct measurements of NOx in both types of boilers, and the results obtained by calculation using equation based on the dimensional analysis, are in a very good accord. When burning coal, the variation between NOx expression from the model and the on-line measurements ranges between -12.23 % and + 9.92 %, and for burning biomass between -0.54 % and 0.48 %.

The intention of the authors is to inform the professional community about the suitability of the dimensional analysis to describe any phenomena for which there is currently no exact mathematical formulation based on differential equations or empirical formulas. Many other examples of dimensional analysis applications in practice may be found in the work of Čarnogurská and Příhoda (2011).

Open access

Tomáš Bacigál and Mária Ždímalová

Abstract

We discuss a new construction method for obtaining additive generators of Archimedean copulas proposed by McNeil, A. J.-Nešlehová, J.: Multivariate Archimedean copulas, d-monotone functions and l1-norm symmetric distributions, Ann. Statist. 37 (2009), 3059-3097, the so-called Williamson n-transform, and illustrate it by several examples. We show that due to the equivalence of convergences of positive distance functions, additive generators and copulas, we may approximate any n-dimensional Archimedean copula by an Archimedean copula generated by a transformation of weighted sum of Dirac functions concentrated in certain suitable points. Specifically, in two dimensional case this means that any Archimedean copula can be approximated by a piece-wise linear Archimedean copula, moreover the approximation of generator by linear splines circumvents the problem with the non-existence of explicit inverse.

Open access

Luiza Ionescu, Maria Toma and Mathurin Founanou

Abstract

At the level of any entity (company), inventory represents an important category of current assets, and implicitly, of total assets. Starting from the importance of this category of assets for the normal development of the production or sales activity, this paper has as priority objectives the following: delimitation of the theoretical aspects regarding the inventory valuation of the sold goods; determining the impact that inventory valuation methods may have on the financial position and financial performance of the company; applied analysis of inventory valuation options. The results obtained from both theoretical and practical research verify the main assumption that the inventory valuation options have a different impact on financial situation and the financial performance of an entity.

Open access

Natália Jasminská, Tomáš Brestovič and Mária Čarnogurská

Abstract

Pyrolysis together with gasification and combustion create a group of so called thermic processes. Unlike the combustion it is based on thermic decomposition of organic materials without any access of oxidative media. Within the pyrolytic process, three main fractions are created: solid residue, pyrolytic gas and organic liquid product - pyrolytic oil. The presented article examines the effects of pyrolysis operational conditions (above all, temperature) on gas products, solid residues and liquid fractions.

Open access

Tomáš Lipták, Valent Ledecký, Marek Ďurej, Oskar Nagy and Mária Kuricová

Abstract

The aim of this study was to investigate the influence of general anesthesia on selected blood parameters in 53 surgical patients belonging to five ASA groups. The venous blood pH during the preoperative period was under physiological values only in the ASA V group of dogs. The lowest average values of pH levels were found in all ASA groups during the 30th minute of the surgical procedure. The pre-operative measurements revealed the average concentration of calcium in the blood serum below the physiological range in the groups with higher anesthetic risk, ASA III, IV and V. Most dogs with hypocalcemia during the whole monitored period were in the ASA III group (69.2%). After premedication and sedation a decrease in the concentration of calcium in all groups was observed, except for the ASA IV group. Changes in the concentration of calcium were significant in the ASA II group (P ≤ 0.01). Between the groups, there were no significant differences reported in calcium concentrations during the monitored period. The lowest average value of phosphorus concentration was recorded in the ASA III group and the highest in the ASA V group. In the postoperative period the increase in phosphorus concentrations was observed in all groups except ASA III. Acidaemia, hypocalcaemia and hyperphosphatemia may present a potential risk mostly in endangered animals, so additional monitoring of these parameters, along with commonly used anesthetic monitoring, is essential and might be significantly helpful.

Open access

Peter Hudák, Mária Maceková, Tomáš Madaras and Pavol Široczki

Abstract

A graph H is defined to be light in a graph family 𝒢 if there exist finite numbers φ(H, 𝒢) and w(H, 𝒢) such that each G ∈ 𝒢 which contains H as a subgraph, also contains its isomorphic copy K with ΔG(K) ≤ φ(H, 𝒢) and ∑x V(K) degG(x) ≤ w(H, 𝒢). In this paper, we investigate light graphs in families of plane graphs of minimum degree 2 with prescribed girth and no adjacent 2-vertices, specifying several necessary conditions for their lightness and providing sharp bounds on φ and w for light K 1,3 and C 10.

Open access

Nicoleta Toma, Maria M. Stancu and Octavian Savu

Abstract

Background. Acute intermittent porphyria (AIP) is a hereditary metabolic aberration resulting from a partial defect in the activity of the enzyme porphobilinogen deaminase (PBDG) during the course of haeme synthesis. Diabetic metabolism may attenuate the episodes of porphyria related symptoms.

Case report. Our subject (male; age 75) was hospitalized one week after onset of diffuse abdominal pain and constipation and overt type 2 diabetes mellitus (DM). The patient’s long history of alcohol intake with acute alcohol consumption 12 days before admission, in the presence of abdominal pain with spectacular remission after oral administration of 5% glucose solution, accompanied by a 2.5 fold increase of urinary porphobilinogen with normal values for porphyrins and urinary lead, and normal full blood count establishes the diagnosis of AIP.

Conclusion We describe a case of AIP probably triggered by acute alcohol consumption, with neurovisceral dominant clinical picture mimicking an acute abdomen. Late disease occurrence as first acute episode at older age accompanied by overt type 2 DM, suggests a latent type of AIP in our patient. The appropriate recognition of latent AIP cases in proband’s offspring prevents unnecessary blind surgery when repeated episodes of unexplained abdominal pain occur.

Open access

María de los Ángeles Tenor Peña, Jesús Claudio Pérez Gálvez, Tomás López-Guzmán and Miguel Jesús Medina Viruel

Abstract

The main objective of this paper is to make an analysis of the relationships between three fundamental constructs in every tourist destination - the perceived value of the attributes of destination, satisfaction and loyalty. Taking into account the perceived value of the tourists who visit this country, three types of visitors have been identified that are considered valid and useful for segmenting the Dominican Republic as a tourist destination: a high perception tourist, a tourist average and a low perception tourist. The attributes valued by the tourists reveal that the perceptive dimension relates to the tourism services and infrastructures of a destination discriminate in a significant way in the degree of satisfaction and attitudinal loyalty declared by the visitors. The conclusions show the need to consider the perceived value of the satisfied and loyal tourist as an essential tool for the Dominican Republic to continue to grow as a tourist destination.

Open access

Lipták Tomáš, Capík Igor, Ledecký Valent, Nagy Oskar, Kuricová Mária, Tóthová Csilla, Maďari Aladár, Farbáková Jana, Petrovič Vladimír and Horňák Slavomír

Abstract

The aim of this study was to compare the effects of different premedication protocols followed by a propofol/fentanyl TIVA on cardio-respiratory and hemodynamic changes in twenty-four dogs randomly divided into two groups (AMD-group: medetomidine, atropine and diazepam; AXD-group: xylazine, atropine and diazepam). Cardiorespiratory variables, acid-base indices, quality of sedation, induction, intubation and recovery were recorded throughout the experiment. Significant changes were observed for the pO2 level, which was increased in the AMDgroup from 90 min. (*P< 0.05) to 120 min. (**P< 0.01) of anesthesia. This can be explained by a reduction of the administration rate of propofol/fentanyl TIVA and oxygenation initiated due to excessively deep anesthesia detected by an anesthetsiologist, leading to improved ventilation and increased pO2. The pCO2 (*P < 0.05) reached more preferable values during the first 30 min. and pH (**P< 0.01) was significantly improved within the first 60 min. in the AXD-group thanks to less depressant effects of xylazine. Within the first 30 min. of anesthesia a significant heart rate difference between the groups was accompanied with significantly higher BP (hypertension) in the AXD-group (10 min. ***P< 0.001, 30 min. **P< 0.01). This points to the possibility of atropine application only in the case of a tendency to bradycardia followed by hypotension. It can be concluded that xylazine is a better option for the premedication of a propofol/ fentanyl TIVA in dogs undergoing a prolonged surgical intervention, in spite of the fact that lower sedation scores were attained. We have detected significantly less adverse cardio-respiratory and hemodynamic effects of xylazine, and a shorter recovery time when compared to medetomidine