Аналитический метод оценки вибраций электромагнитного происхождения в семифазной машине переменного тока

An analytical evaluation method for output waveform quality of space vector pulse width modulation (PWM) strategies applied in neutral-point-clamped three-level converter (3L-NPC) is proposed in this paper. Low frequency error caused by neutral point voltage ripple and high frequency error introduced by space vector synthesis were both taken into account, and the unified error model of output current ripple was established. By taking continuous and discontinuous modulation strategies as examples, the unified error model was validated through Fourier analysis of the experimental results. The proposed evaluation method will be helpful for the switching sequence optimization and the modulation strategy selection.

An analytical method for approximate performance evaluation of binary linear block codes using an additive white Gaussian noise channel model with binary phase-shift keying modulation is presented. We focus on the probability density function of the bit log-likelihood ratio (LLR), which is expressed in terms of the Gram-Charlier series expansion. This expansion requires knowledge of the statistical moments of the bit LLR. We introduce an analytical method for calculating these moments. This is based on some recursive calculations involving certain weight enumerating functions of the code. It is proved that the approximation can be as accurate as desired, if we use enough terms in the Gram-Charlier series expansion. Numerical results are provided for some examples, which demonstrate close agreement with simulation results.

The paper deals with the functioning of commodity exchanges in the Czech Republic, and is particularly concerned with exchanges trading in agricultural production commodities. The introductory part of the paper is oriented towards the theory and general structure of commodity exchanges; the other parts subsequently deal (in more detail) with the most problematic areas of their operation in the Czech Republic up to the present time. Within this part of the paper, the method of analytical evaluation is used for examining, above all, the existing legal regulation, the structure and function of these exchanges. Subsequently, using the method of comparative analysis, selected key aspects of their operation are compared with the theoretical requirements of their functioning as well as with the everyday functioning of this kind of exchange in economically developed countries. Findings gathered this way are subsequently utilized in the concluding part of the paper, the subject matter of which is a prediction about the possible variants of the future development of Czech agricultural commodity exchanges, with regard to the assumed admission of the Czech Republic to the European Union.

Qualitative evaluation of courses intended for patients suffering from chronic diseases: New observation method for the continuous training of the healthcare team

Consideration on Evaluation Methods Applied to Education for Undergraduate Presentations ­ Focusing on the analytic evaluation method

Specific features of composite-material structural design. Analysis of stiffness, strength and fatigue characteristics of multilayer composites. Methods of composite structural strength analysis. Methods for experimental and analytical evaluation of the residual strength of composite structures with stress concentration. Methods of design and analysis of joints. Application of the finite-element method to the structural analysis of composite structures. Characteristics of the certification of composite structures. Index.

Automated guided vehicle (AGV) transportation systems are an important component of flexible warehouse systems, and research on the performance evaluation of AGV transportation systems contributes to the optimization and decision-making of flexible warehouse systems. Compared to simulation and experimental methods, analytic methods require less computational time, which is more applicable when integrated with optimization and decision-making methods. However, the previous analytical methods for performance evaluation neglected the velocity change and collision avoidance of AGVs, which decreased the evaluation accuracy. Therefore, herein, a throughput evaluation methodology based on AGV route decomposition is proposed for AGV transportation systems. In the proposed methodology, an AGV transportation system is modeled as an open queueing network model considering the velocity change of AGVs. The open queueing network model is decomposed into sub-models based on preplanned AGV routes, considering the collision avoidance among AGVs, to decrease the analysis complexity and computational time. Finally, the throughput of the AGV transportation system is obtained by the throughput sum of the sub-models corresponding to the unload stations. The numerical results indicate that the proposed methodology evaluates the throughput of an AGV transportation system with an accuracy of ≥94%. This study will facilitate the efficient throughput and decision-making of AGV transportation systems.

Objective.To develop and evaluate an analytical method for calculating the system matrix of a dynamic cardiac single photon emission computed tomography (DC-SPECT) system, eliminating the need for computationally intensive Monte Carlo (MC) simulations.Approach.An analytical model was proposed for system matrix generation, incorporating solid angle calculations adapted for square-shaped pinhole collimators. The resulting sensitivity maps were validated against MC simulation results. Image reconstructions using the proposed analytical model were compared to those using an MC-simulated system matrix. Additionally, the overall system performance, including sensitivity and spatial resolution, was assessed using MC simulations.Main results.The analytical sensitivity map showed good agreement with MC-based results. Reconstructed images using the analytical model preserved key features but showed reduced performance compared to MC-based reconstructions. MC simulations of DC-SPECT demonstrated a spatial resolution of 5.5 mm for hot regions and 6.0 mm for cold regions, with an overall system sensitivity of 0.07% over a 15 cm diameter spherical field of view.Significance.The proposed analytical method offers a fast and practical alternative to MC-based system matrix generation, enabling efficient system design and prototyping. While its use in clinical image reconstruction requires further evaluation, the model provides a promising tool for accelerating the development of next-generation DC-SPECT systems.

Existing analytical methods for calculating electron-beam welding modes, which provide welds with required penetration depth, are described, and main disadvantages of these methods are shown. A new calculation method based on a model of moving cylindrical heat source, which involves moving of a cylinder with constant surface temperature in an infinite plate, is proposed. The proposed calculation method takes into account energy losses during metal melting and its partial evaporation. A comparison of experimental and calculated data obtained using the developed method and existing methods, is presented. Plates with a thickness of 32 mm from 5V titanium alloy, 27 mm from 40 Kh13 steel and 20 mm from D16 duralumin were used for experiments. It was shown that the developed method application made it possible to calculate with appropriate accuracy a required beam power during EBW of various materials.

This paper presents an analytical method for the performance evaluation of the correlation-based impulse radio (IR) receivers, which detect the data based on synchronizing the received signal with a locally generated template pulse. In this paper, a phase interpolation technique is employed to preserve synchronization accuracy with low power consumption. The analytical method computes the spectral density of jitter at the phase interpolator output, resulting from both flicker and thermal noise components. The analysis considers the aliasing phenomenon due to the sampling of the noise to predict the induced jitter accurately. Bit error rate (BER) of the receiver is also statistically estimated in terms of the induced jitter on the template pulse, the noise effect of the receiver chain, and the template signal level. The proposed estimation procedure is validated by comparing its results with transient noise simulations. It is shown that increasing the template signal range in the correlator and improving the linearity of the phase interpolation transfer curve, at a given power consumption, enhances the receiver sensitivity by 2 and 3.5 dB, respectively. The BER estimation results also reveal that the effect of the template signal jitter on the sensitivity of the correlation-based IR receivers becomes dominant with the increasing input signal level.

While there are various analytical methods for elasticity evaluation, those with micrometer-order spatial resolution are still under developing. As some of biological tissues such as capillary vessels and cochlea are very small and/or highly heterogeneous, development of analytical techniques with such high spatial resolution has been desired for biological and medical purposes. Especially, the elasticity of capillary vessels (several micrometer in diameter) would be an important indicator to find out early diseases. To measure the local elasticity for such small and/or heterogeneous samples, we have proposed an approach based on a temporal waveform of photoacoustic (PA) signal, i.e., time-domain PA. As the time-domain PA contains both the vibrating frequency and the sound propagation time after the excitation, itprovides the information on the local elasticity (from the frequency) at a specific depth (from the propagation time) of samples. In the present study, the signal from collagen sheets were obtained and analyzed as models of blood vessel walls and scaffolds for regenerative medicine. In contrast to previous studies using the agarose gel which showed a single frequency peak, the signal from the collagen sheets was mainly composed of two frequency peaks, assignable to surface and bulk vibration. Further, the bulk vibration was found to sensitively reflect the elasticity of the samples. Since the PA effect can be induced only at the position where the light absorber exists, the analytical method proposed here would allow us to measure the local elasticity and its spatial distribution in blood vessels and other tissues.

Cluster analysis of stabilometry results in 251 subjects (129 men and 122 women, age 20-60 years) was carried out. Four methods were used in the study: European stabilometry variant, Romberg test (European variant), Romberg's test (American variant), and Romberg's test (American Universal variant). Cluster analysis has shown virtually the same diagnostic informative value of all 4 methods. The absolute and relative stabilometry parameters are the most objective, this validating their clinical usefulness. The frequency and amplitude parameters possess no diagnostic significance. The European stabilometry variant is the best fit for practical use and provides information about the function of the ocular, maxillofacial, and other components of the postural system.

The study focuses on comparative analysis of accuracy for various methods for evaluation of the average causal effect (ATE). A range of methods includes the t-test, linear regression, and several data matching techniques such as nearest neighbor, full matching, and subclassification. The methods are tested using the generated synthetic samples of varying dimensions from 250 to 1000, with different proportions of data divided into experimental and control groups (50/50, 70/20, and 90/10), under the assumption of normal, exponential, and logarithmic distribution of predictors. The Mean Absolute Percentage Error (МАРЕ) error metric is used to evaluate the accuracy of methods. The numerical experiments reveal that using t-test and linear regression techniques leads to a significant under- or overestimation of the ATE values, while the full matching methods produce more accurate results regardless of covariate probability distributions. Also, the balanced and larger samples provide the ATE evaluations with higher accuracy. The obtained results can be used to justify the proper method for evaluation of casual effects under the direct influence of the binary nature and nonlinearity of one of the affecting factors.

Service plays an essential role in an organisation. Service plays a vital role in the healthcare sector, as most elements are intangible in nature. Measurement of service quality in the healthcare sector is difficult for researchers (Daniel and Berinyuy, 2010; Fernando et al., 2011). In this article, researcher discussed service quality factors for the healthcare sector. The researcher fits the new service quality model for the healthcare sector under Parasuraman dimensions (RATER model). The researcher fixed 30 sub-criteria for evaluation of services in hospitals/healthcare and used analytical network process (ANP) for factors which influence service quality in hospitals or healthcare sectors. The researcher next applied analytical hierarchy process (AHP) and preference ranking organisation method for enrichment evaluation (PROMETHEE) tools as corporate hospitals provide the best (ranked) service quality (SERVQUAL) from the public and societal aspects. The researcher chose five corporate healthcare/hospitals in India. This research is vital to future researchers who evaluate the service quality of healthcare/hospitals.

An analytical method for an exact evaluation of the coset probabilities of algebraically decoded linear nonbinary block codes used on stochastic finite state channels is presented. The analysis can be performed in a transform domain showing an easy computational structure. The transform coefficients are connected with the coset probabilities by a complex generalization of the Walsh-Hadamard-transformation.