The rapid growth of Internet-of-Things (IoT) in the current decade has led to the development of a multitude of new access technologies targeted at low-power, wide area networks (LP-WANs). However, this has also created another challenge pertaining to technology selection. This paper reviews the performance of LP-WAN technologies for IoT, including design choices and their implications. We consider Sigfox, LoRaWAN, WavIoT, random phase multiple access (RPMA), narrowband IoT (NB-IoT), as well as LTE-M and assess their performance in terms of signal propagation, coverage and energy conservation. The comparative analyses presented in this paper are based on available data sheets and simulation results. A sensitivity analysis is also conducted to evaluate network performance in response to variations in system design parameters. Results show that each of RPMA, NB-IoT, and LTE-M incurs at least 9 dB additional path loss relative to Sigfox and LoRaWAN. This paper further reveals that with a 10% improvement in receiver sensitivity, NB-IoT 882 MHz and LoRaWAN can increase coverage by up to 398% and 142%, respectively, without adverse effects on the energy requirements. Finally, extreme weather conditions can significantly reduce the active network life of LP-WANs. In particular, the results indicate that operating an IoT device in a temperature of −20 °C can shorten its life by about half; 53% (WavIoT, LoRaWAN, Sigfox, NB-IoT, and RPMA) and 48% in LTE-M compared with environmental temperature of 40 °C.
Network slicing, a key enabler for future wireless networks, divides a physical network into multiple logical networks that can be dynamically created and configured. In current IEEE 802.11 (Wi-Fi) networks, the only form of network configuration is a rule-based optimization of few parameters. Future access points (APs) are expected to have self-organizational capabilities, able to deal with large configuration spaces in order to dynamically configure each slice. Deep Reinforcement Learning (DRL) can achieve promising results in highly dynamic and complex environments without the need for an operating model, by learning the optimal strategy after interacting with the environment. However, since the number of possible slice configurations is huge, achieving the optimal strategy requires an exhaustive learning period that might yield an outdated slice configuration. In this paper, we propose a fast-learning DRL model that can dynamically optimize the slice configuration of unplanned Wi-Fi networks without expert knowledge. Enhanced with an off-line learning step, the proposed approach is able to achieve the optimal slice configuration with a fast convergence, which is attractive for dynamic scenarios.
We investigate strong-field ionization of linear molecules by a two-color laser field of frequencies rω and sω having coplanar counterrotating or corotating elliptically polarized components (ω is the fundamental laser field frequency and r and s are integers). Using the improved molecular strong-field approximation we analyze direct above-threshold ionization (ATI) and high-order ATI (HATI) spectra. More precisely, reflection and rotational symmetries of these spectra for linear molecules aligned in the laser-field polarization plane are considered. The reflection symmetries for particular molecular orientations, known to be valid for a bicircular field (this is the field with circularly polarized counterrotating components), are valid also for arbitrary component ellipticities. However, specific rotational symmetries that are satisfied for HATI by a bicircular field, are violated for an arbitrary elliptically polarized field with counterrotating components. For the corotating case and the N2 molecule we analyze molecular-orientation-dependent interferences and plateau structures for various ellipticities.
Dr. Bruno von Curinaldi, came to Mostar from Zadar (Croatia) and started to work as Director of Mostar hospital in 1879 (1-3). In that time in Mostar also worked Dr. Franjo Hus (died in Mostar 1940), Dr. Otto Weiss (came to Mostar in 1882 from Bilroth’s hospital in Vienna, and in 1894 he moved to State hospital in Sarajevo to chair Gynaecology-Obstretics department), Dr. William Tonner (from Prague, well known as physician who treated poor people in Mostar free of charge (written in journal "Novi hercegovacki bosiljak" in 1885) (4), Dr. Fakete Samule (from Hungary, died in Mostar due to infection when performing autopsy), Dr. Trepeljka and Dr. Kestner (worked in 1886, during epidemic of cholera in Mostar), Dr. Braun, Dr. Herman, Dr. Koralek, Dr. Tausig (all of them physicians in Military hospital in Mostar), Dr. Moritz Englander (surgeon), Dr. Drago Mesliger, Dr. Kohn, Dr. Goldfarb, Dr. Franjo Bulat (famous physician, but also musician, Director of “Hrvatska glazba” in Mostar which organized a lot of concerts in Mostar, died in 1947), Dr. Gotfrid Holer, Dr. Pollacek. From Vienna to Mostar sometime was coming famous ophtalmologist Dr. Dragutin Heinzel (worked at Clinic of professor Fuchs), Dr. Jerko Bulat, son of Franjo Bulat spent his work time in Mostar. Dr. Nikola Grazetic also was engaged in Mostar’s cultural manifestations with Franjo Bulat (4).
The paper deals with the three-dimensional (3D) modelling based on data acquired from 2D laser sensor and IMU (Inertial Measurement Unit) attached to the UAV (Unmanned Aerial Vehicle). The used multi-sensor unit produces 2D scans and provides information about Euler angles or quaternions. These angles are used to describe the UAV orientation in 3D space, more precisely the orientation of the laser sensor. In order to generate 3D occupancy map it is necessary to rotate the laser sensor around its axis yielding the 2D scans being mapped on 3D space using quaternions. Inertial sensor and Sweep LiDAR laser measurements are transmitted to the single board computer Odroid XU4 (SBC). The data fusion was performed under ROS (Robot Operating System) installed on the SBC, producing 3D space points. These points are transmitted over the network to the central computer on which the UAV localization and mapping processes are done within the ROS. The effectiveness of the proposed system for 3D modelling of the UAV environment is verified by experiment.
The paper presents a custom-made radiometric thermography system which provides a full radiometric IR inspection. It contains heterogeneous stereo-vision system with RGB and thermal camera, as well as the processor unit with developed embedded software modules. The software units were realized using C++ programming language within ROS development environment. In order to obtain the better representation of points in the space as well as their projections on the cameras planes, the stereo calibration was performed. The correspondence between RGB and thermal images is represented with homography. The object detection is performed using OpenCV feature detectors, while the recognition is carried out by Hu moments computation and K-means clustering. For the showcase, incandescent light bulbs, LED light bulbs and quartz heaters are detected and recognized as such. The developed system is capable of providing a heterogeneous inspection of heating systems, power lines, etc.
Direct numerical simulations (DNS) of knitted textile mechanical behavior are for the first time conducted on high performance computing (HPC) using both the explicit and implicit finite element analysis (FEA) to directly assess effective ways to model the behavior of such complex material systems. Yarn-level models including interyarn interactions are used as a benchmark computational problem to enable direct comparison in terms of computational efficiency between explicit and implicit methods. The need for such comparison stems from both a significant increase in the degrees-of-freedom (DOFs) with increasing size of the computational models considered as well as from memory and numerical stability issues due to the highly complex three-dimensional (3D) mechanical behavior of such 3D architectured materials. Mesh and size dependency, as well as parallelization in an HPC environment are investigated. The results demonstrate a satisfying accuracy combined with higher computational efficiency and much less memory requirements for the explicit method, which could be leveraged in modeling and design of such novel materials.
Abstract Ferrofluids based on magnesium substituted magnetite nanoparticles MgxFe3−xO4 (x = 0.1; 0.2; 0.4) were synthesised by a chemical co-precipitation method. Their physical properties have been compared with those of the magnetite based ferrofluid obtained by the same synthesis route. Both XRD and TEM studies showed particle size decrease with the increased Mg content while DLS experiments pointed to the more prominent aggregation of Mg-containing nanoparticles. Magnetic properties investigation conducted on the powder (i.e. dried) specimens showed decrease of magnetization values with increased Mg content except for the lowest concentration of x = 0.1 where substantial saturation magnetization rise of about 40% was recorded at room temperature. Heating abilities of the studied ferrofluids under the applied AC fields (SAR values) also showed decreasing trend with the increased Mg content even for x = 0.1 sample despite its elevated magnetization value. This trend has been understood as a consequence of the changed intrinsic nanoparticle properties such as size and magnetic anisotropy, as well as contribution of a collective behaviour due to an increased nanoparticle aggregation in Mg-doped systems.
High-order harmonics generated by a linearly polarized laser field are also linearly polarized. Having in mind that for various application, such as the exploration of magnetic materials, chiral molecules etc., we need circularly polarized high harmonics which serve as coherent soft x-rays, we explore high-order harmonic generation by the so-called bicircular laser field. This field consists of two coplanar counter-rotating circularly polarized fields of different frequencies equal to integer multiples of a fundamental frequency ω. High harmonics generated by such field are circularly polarized with helicity alternating between +1 and −1. Combining a group of such harmonics, instead of obtaining a circularly polarized attosecond pulse train, one obtains a pulse with unusual polarization properties. But, if the harmonics of particular helicity are stronger, i.e., if we have helicity asymmetry in a high-harmonic energy interval, then it is possible to generate an elliptical or even circular pulse train. We theoretically investigated a wide range of bicircular field-component intensities (I1 and I2) and found regions where both the harmonic intensity is high and the helicity asymmetry is large. Particular attention is devoted to the ω−2ω and ω−3ω bicircular fields and atoms having the s and p ground states. In our calculations we use strong-field approximation and quantum-orbit theory. We show that, even in the extreme case of I2 = 8I1, for an ω−3ω bicircular field, high-order harmonic generation is more efficient than in the I2 = I1 case. The obtained results are explained analyzing the relevant electron trajectories and velocities, which follow from the quantum-orbit theory. For the atoms having p ground state the helicity asymmetry parameter is large for a wide range of high-harmonic photon energies, while for the atoms having s ground state the helicity asymmetry parameter can be large only for low harmonics. We confirm this by averaging the obtained results over the intensity distribution in the laser focus.
Introduction: The most appropriate choice of pharmacological treatment of heart rhythm disorders occurring in patients with chronic obstructive pulmonary disease (COPD) and cardiovascular comorbidity is often a topic of debate between pulmonologists and cardiologists in clinical practice, although numerous studies and clinical trials have demonstrated evidence to support the use of selective beta-blockers (BBs) in these patients. Aim: To examine the difference in the number of exacerbations in patients treated with a combination of verapamil and digoxin or BB alone in patients with different COPD stages. Patients and methods: The study included 68 patients (n = 68) diagnosed with COPD who were followed-up during a 12-month period, and the number of exacerbations were analyzed. The patients were divided into two groups according to the stage of COPD: GOLD II (moderate), and GOLD III (severe), and in each group a subdivision was established in relation to the use of either a combination of verapamil and digoxin or the use of BBs alone in pharmacological treatment. The inclusion criteria for patients were defined as following: a) established diagnosis of COPD according to present or deteriorated relevant clinical symptoms and signs, b) the ejection fraction (EF) of a left ventricle (LV) >35%, and c) spirometric cut-points classified as GOLD II (FEV1 / FVC <0.7, FEV1 predicted 50-80%), or GOLD III (FEV1/FVC <0.7, FEV1 predicted 30-50%) stage of the COPD. The exclusion criteria were EF of LV <35% and a lethal outcome during a follow-up period (2 patients were encountered). Exacerbation was defined as functional deterioration of the COPD symptoms verified by spirometric functional testing, frequency of hospitalizations according to GOLD stage assignment or verified clinical symptoms deterioration. Results: Regardless the pharmacological treatment, there is a statistically significant increase in the number of COPD exacerbations, in a 12-month period follow-up, in the GOLD III group (severe) compared to the GOLD II group (moderate). In the group of patients taking verapamil and digoxin, a two-tailed t-test was used to analyze the results between the GOLD II and GOLD III stage groups, p = 0.01, and 2. In the group of patients taking BBs, a two-tailed t-test was also used to analyze the results between the GOLD II and GOLD III stage groups, p = 0.003). Within the COPD GOLD II stage group, there appears to be no statistically significant difference in the number of exacerbations between the patients taking verapamil and digoxin (n = 24) and the patients taking BBs alone (n = 15), although, in patients taking BBs alone, there appears to be a trend towards a decrease in the exacerbations compared to the number of exacerbations in patients taking verapamil and digoxin (p = 0.007). Within the COPD GOLD III stage group, there is no difference in the number of exacerbations between the patients taking verapamil and digoxin (n = 20), and the patients taking BBs alone (n = 9), as analyzed by a two-tailed t-test, p = 0.577. Conclusion: Use of selective BBs in the treatment of cardiovascular comorbidity in patients with COPD represents a far better choice of pharmacological approach in the treatment of patients diagnosed with COPD GOLD II (moderate) stage.
The aim of the research is to determine the characteristics of the prosocial behavior of primary and high school students in terms of the structure of leisure time. The sample of respondents consists of 230 students of the final grades of primary and high schools, both genders, aged 14-19. The research was conducted in the area of Tuzla during the school year 2017/2018. years. The survey used the measuring instrument "Scale of self-assessment of juvenility behavior YSR". Mann Whitney U test was used for statistical analysis of data. When analyzing the prosocial behavior of primary and high school students in terms of the structure of leisure time, statistically significant differences at the level of p≤0,05 were established in such a way that students with structured leisure time compared to students whose leisure time is not structured more often : are fairly honest, they do things better than most children, they can be pretty friendly, they are skillful with their hands, they fight for their rights, enjoy being with other people, they like to make others laugh, they like to help others.
Reconstructions of the primordial power spectrum (PPS) of curvature perturbations from cosmic microwave background anisotropies and large-scale structure data suggest that the usually assumed power-law PPS has localised features (up to \sim 10\%∼10% in amplitude), although of only marginal significance in the framework of \LambdaΛCDM cosmology. On the other hand if the cosmology is taken to be Einstein-de Sitter, larger features in the PPS (up to \sim 20\%∼20% in amplitude) are required to accurately fit the observed acoustic peaks. Within the context of single clock inflation, we show that any given reconstruction of the PPS can be mapped on to functional parameters of the underlying effective theory of the adiabatic mode within a 2nd-order formalism, provided the best fit fractional change of the PPS, \Delta{P}_{R}/{P}_{R}ΔPR/PR is such that (\Delta{P}_{R}/{P}_{R})^3(ΔPR/PR)3 falls within the 1\,\sigma1σ confidence interval of the reconstruction for features induced by variations of either the sound speed c_\mathrm{s}cs or the slow-roll parameter \epsilonϵ. Although there is a degeneracy amongst these functional parameters (and the models that project onto them), we can identify simple representative inflationary models that yield such features in the PPS. Thus we provide a dictionary (more accurately, a thesaurus) to go from observational data, via the reconstructed PPS, to models that reproduce them to per cent level precision.
Abstract Background: In recent years’ income inequality has been an economic issue. The primary instrument for redistributing income is personal income tax. However, based on economic theory income inequality concerns indicators such as wages, transfer payments, taxes, social security contributions, and geographical mobility. Objectives: The objective of this paper is to examine the impact of certain labor market indicators on personal income taxation in Federation of Bosnia and Herzegovina (FB&H). Methods/Approach: Since personal income taxation consists of a very broad definition and for the purpose of this research only, income from dependent (employment) activity is observed. The econometric analysis is conducted using error correction modeling, as well as forecast errors variance decomposition. Results: The error correction model is estimated, and the cointegrating equation indicates that monthly wage and number of employees statistically significantly positively affect personal income taxes in FB&H in the long-run. After two years, the selected labor market indicators explain a considerable part of forecasting error variance of personal income tax revenues. Conclusions: The implementation of reforms in the labor market and tax policies of the FB&H is suggested. In order to achieve necessary reforms, efficient governance and general stable political environment are required.
Health literacy (HL) has become an important area of research. The aim of this study was to evaluate the HL of primary healthcare patients in the Republic of Srpska (RS), Bosnia and Herzegovina (B&H) and to identify socioeconomic and health factors associated with HL. This cross-sectional study among 768 patients was conducted in two healthcare centres between March and May 2017, using the Short Test of Functional Health Literacy in Adults (S-TOFHLA). Analysis was done using descriptive and inferential statistics (a chi-squared test and logistic regression). Inadequate and marginal HL was found in 34,6% of respondents. Socioeconomic and self-reported health factors were significantly related to HL. An age of 55 years and over (OR 1.02), living in a rural environment (OR 2.25), being divorced (OR 3.32), being insufficiently physically active (OR 1.29), having poor income (OR 1.96), having more than three chronic diseases (OR 1.94), and poor health (OR 1.59) were significantly corelated with inadequate and marginal HL. The results of our study indicate that a low level of HL is related to the elderly, having a divorce, having a rural residence, poor income, having more than three chronic diseases, poor health, and insufficient physical activity. Further evaluation, monitoring, and activities to improve HL are of great importance for patients’ health outcomes.
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