Municipal Management in Brazil

This paper aimed to point out the determinants of the effectiveness of Municipal Management in Brazil. It was a quantitative, descriptive research, with secondary data from 2015 to 2017, available at the Rui Barbosa Institute web site – 11 variables correlated with the effectiveness of management. The sample was comprised of Brazilian municipalities. The results were estimated by logistic regression with balanced panel data and interpreted by the odds ratio criterion. The results showed that population size and the mayor’s reelection have a positive and statistically significant relationship to explain the effectiveness of management. On the other hand, the number of candidates for mayors, and disapproved expenses showed a negative and statistically significant relationship to explain the effectiveness. By addressing the effectiveness of municipal management, this article fills a gap in the literature because it brings to the debate the relevance of the evaluation phase of the public management to improve its quality and/or mitigate negative impacts on the population.

Inaccessible rolling bearing diagnosis using a novel criterion for Morlet wavelet optimization

The objective of this research is to diagnose an inaccessible rolling bearing by indirect vibration measurement. In this study, a shaft supported with several bearings is considered. It is assumed that the vibration for at least one bearing is not recordable. The purpose is to diagnose inaccessible bearing by the recorded data from the sensors located on the other bearings. To achieve this goal, the continuous wavelet transform is used to detect weak signatures in the available vibration signals. A new criterion for adjusting the scale parameter of continuous wavelet transform is proposed based on the amplitude of the bearing characteristic frequencies. In this criterion, the optimal scale is selected to maximize the amplitude of bearing characteristic frequencies in comparison with the amplitude of the other frequencies. The results of the proposed method are compared with a popular method, energy-to-entropy ratio criterion, using two different sets of run-to-failure experimental data. Results indicate that the proposed method in this article is more effective and efficient for extracting the weak signatures and diagnosing inaccessible bearings from the recorded vibration signals.

SIMULATION OF ULTRA DENSE 5G RADIO ACCESS NETWORKS WITH BEAMFORMING

In this paper, we investigate the connectivity and probability of successful radio reception in the Poisson model of a 5G ultra-dense radio access network formed by devices with the possibility of location aware beamforming. The difference be-tween the proposed model and the existing prototypes is the complex account for the gains of devices, as well as the influence of radio wave propagation losses, slow and fast fading in the radio channel on the performance of the radio access network. The study is carried out for sessions of directional and omni-directional radio communication, and the beamforming mode is based on the preliminary positioning of neighboring devices. Mathematical modeling of a set of simultaneously operating radio lines in the Poisson model of an ultra-dense 5G radio access network makes it possible to estimate the gain in connectivity and the probability of successful radio reception when forming a beam based on preliminary positioning of devices in comparison with the case of omnidirectional antennas. The results of mathematical modeling of a ultra-dense radio access network with devices equipped with six-element circular antenna arrays showed a significant increase in connectivity indicators and the probability of successful radio reception in comparison with the case of omnidirectional antennas and confirmed the possibility of spatial multiplexing of simultaneous transmissions with a territorial separation of devices on 20% of the range of radio coverage based on the signal-to-noise ratio criterion. The result of the study is the establishment of the dependences of the connectivity and the probability of successful radio reception for an ultra-dense 5G radio access network, built on the basis of devices operating in the adaptive diagramming mode, as well as confirmation of the possibilities of spatial multiplexing of simultaneously operating transceiver devices with their territorial separation by 20% of the range of radio coverage based on the signal-to-interference ratio criterion. The obtained dependences of connectivity and the probability of successful radio reception allows to scientifically substantiate construction of an initial approximation of ultra-dense 5G radio access network from devices with the possibility of beamforming based on positioning, taking into account practical recommendations for their territorial diversity with an ultra-dense distribution.

Risk stratification of thromboembolic complications development in surgical patients

Aim. Creating a mathematically based scale of risk stratification of thromboembolic complications in patients with acute abdominal organs pathology requiring urgent surgical treatment.Material and methods. This work is based on data from 185 case reports of patients with acute surgical diseases of the abdominal organs that had undergone emergency operations. Clinical and statistical analyses were carried out and the most significant risk factors for venous thromboembolic complications were identified. By digitally estimating the specific gravity of each of the factors, the method of sequential probability ratio criterion was applied to the obtained data.Results and discussion. Based on a retrospective analysis of clinical records, 13 most informative prognostic criteria for thromboembolic complications formed in the prognostic table were identified. Each sign, depending on its value, had a specific gravity. For the convenient using of the prognostic scale in practice, the indicators of natural logarithms are translated into arbitrary units (points). The results are checked on available archival records. The overall forecast reliability was 97%.Conclusion. The proposed prognostic scale made it possible to optimize the likelihood of a feasibility study in patients with acute diseases of the abdominal organs.

A Loop-Line Antenna with Enhanced Bandwidth of Circular Polarization

We investigate a circularly polarized (CP) transmission-line antenna composed of loop radiation elements, called a loop-line antenna. To enhance the CP wave bandwidth, an isolated loop radiation element is first analyzed using the method of moments. It is found that a CP wave bandwidth for a 3 dB axial-ratio criterion has a maximum value of 8%. On the basis of the analysis results, we design the loop-line antenna. It is found that the antenna shows a CP wave bandwidth of 6%, which is twice as wide as that of a conventional loop-line antenna. The analysis results are verified with experimental ones. In addition, a condition for wideband CP radiation is discussed and found to be a composite radiation element consisting of two CP loops.

Modified Crossed-Wire Antennas Radiating a Circularly Polarized Conical Beam

Two types of modified crossed-wire antennas are investigated to enhance a circularly polarized (CP) wave bandwidth. The wire length of each antenna is increased twice as long as that of the original antenna. First, a bent-type antenna is analyzed using the method of moments. It is found that the CP wave bandwidth for a 3 dB axial ratio criterion is twice as wide as that of the original antenna. Next, a spiral-type antenna is analyzed. It is revealed that the antenna shows a CP wave bandwidth of 28%, which is wider than that of the original antenna by a factor of 3.5. The analysis results are validated by experimental work.

Modelling industry interdependency dynamics in a network context

Purpose Interdependency among industries is vital for understanding economic structures and managing industrial portfolios. However, it is hard to precisely model the interconnecting structure among industries. One of the reasons is that the interdependencies show a different pattern in tail events. This paper aims to investigate industry interdependency with the tail events. Design/methodology/approach General predictive model of Rapach et al. (2016) is extended to an interdependency model via least absolute shrinkage and selection operator quantile regression and network analysis. A dynamic network approach was applied on the Fama–French industry portfolios to study the time-varying interdependencies. Findings A denser network with heterogeneous central industries is found in tail cases. Significant interdependency varieties across time are shown under dynamic network analysis. Market volatility is identified as an influential factor of industry connectedness as well as clustering tendency under both normal and tail cases. Moreover, combining dynamic network with prediction direction information into out-of-sample industry return forecasting, a lower tail case is obtained, which gives the most accurate prediction of one-month forward returns. Finally, the Sharpe ratio criterion prefers high-centrality portfolios when tail risks are considered. Originality/value This study examines the industry portfolio interactions under the framework of network analysis and also takes into consideration tail risks. The combination of economic interpretation and statistical methodology helps in having a clear investigation of industry interdependency. Moreover, a new trading strategy based on network centrality seems profitable in our data sample.