Loss Distribution Research Articles

Повышение адекватности моделей электромеханотронных систем

Development of electromechanotronic systems is connected with modeling and calculation of processes of various kinds. Electromagnetic, mechanical and thermal processes are analyzed, control, regulation, protection, monitoring and diagnostics problems are solved. Systems may contain a large number of power semiconductor elements. Short-term and multi-hour processes are calculated. Taking into account mutual connections of processes of various kinds in calculations of complex systems requires inadmissibly large expenditures of machine time. The problems are solved under more or less significant assumptions, which leads to a decrease in the adequacy of the results. The methods of systems calculation are proposed, which allow to reduce machine time consumption and to use more detailed description of installations and more accurate computer models. Possibilities of calculation of processes by «smooth components» of variables, and also application of dual models, in which speed and accuracy are combined, are considered. As an example, a system with an active cascade frequency converter containing 780 transistors and diodes, parasitic inductances and snubber circuits, and a vector-controlled induction motor with ladder circuits accounting for current displacement is analyzed. The model takes into account energy losses in the converter and in the motor, as well as the distribution of losses by components. It also takes into account emergency operation modes associated with disconnection of a part of low-voltage units of the cascade converter and maintenance of power quality at its input and output by symmetrization of the main current components and suppression of parasitic components.

The health Loss Distribution of Coal-fired Power Plants and the relationship to Air Pollution Charges

In this study, the regional health loss due to the air pollution of a coal-fired power plant is analyzed by using the atmospheric dispersion model. AERMOD was used to simulate the increment concentration map of point source emission, and the GIS geographic information system was used to displace the distribution of air pollution concentration and regional health loss in grid receptors. The data of the continuous automatic monitoring facilities and the source of pollution sources were analyzed. Moreover, the effects of emissions, seasons, population, and distance on the simulated concentration were evaluated. The various influencing factors of air pollution concentration were evaluated.the R2 value of the empty product prediction map in summer has a better correlation with the concentration from monitor station, between 0.38 and 0.83, and the sulphur dioxide correlation has the best R2 value of 0.83. AERMOD was used to combined with pollutant emissions, weather, and terrain data, to simulate the distribution of rising concentration values due to coal-fired power plant emissions within the research area, and the study used the simulated rising concentration values to calculate the health loss. [1] The study used health loss of 25,647,291,161 NTD/year and medical loss of 319,153,198 NTD/year.

Exploring the Characteristics and Path of Internationalization Development of Vocational Education Based on the Information Diffusion Model

Abstract Internationalization of higher education has become an inevitable trend under the impetus of world economic integration and informationization. This paper adopts the information diffusion technique in the fuzzy information optimization method to construct an assessment model for internationalization development of vocational education. Explicit sample data are turned into fuzzy sets, information diffusion points are built using a two-dimensional average information diffusion model, and the estimated loss and probability distribution of information diffusion are calculated to assess the internationalization development level of vocational education. The constructed indicators set people’s awareness of the internationalization development of vocational education and the dissemination effect, analyzed the internationalization development trend of vocational education in the past five years by combining the Google search data, and explored the impact of internationalization development of vocational education based on the indicators of output level and quality level. The results show that the communication effects of internationalization of vocational education are all rated between (3.3, 3.6), and the attention to the internationalization development of vocational education has increased from 10% to 70% in six years. This study provides suggestions and strategies for advancing the internationalization of higher vocational education in China, which is conducive to steadily increasing the internationalization of higher vocational education in China and improving the level of schooling.

Single versus Two Implants-assisted Mandibular Overdentures: A Finite Element Analysis Study

Introduction: Single-implant Overdentures (1IODs) have gained popularity as a more economical protocol than Two-implant Overdentures (2IODs). However, concerns have existed about the longevity of using a single implant compared to two implants. Aim: To investigate the marginal bone loss and stress distribution around dental implants assisting 1IODs compared to 2IODs within five years of clinical service. Materials and Methods: This randomised clinical trial was conducted at the Department of Prosthetic Dental Sciences, College of Dentistry of Qassim University in the Kingdom of Saudi Arabia from June 2018 to September 2023. Total 40 completely edentulous male patients, aged 50 to 60 years, were blindly allocated to two groups. Group I included 20 patients who received two implants at the canines’ regions, and Group II included 20 patients who received one implant under their mandibular overdentures at the midline of the mandible. The implants in both groups were followed up immediately after loading, at six and 12 months, three years, and five years for probing depth, mobility, and vertical bone loss. Finite Element Analysis (FEA) was used for stress analysis around the implants. One-way Analysis of Variance (ANOVA) and Mann-Whitney tests were used for statistical analysis at a significance level of p<0.05. Results: Group II had significantly more fractures and required more new dentures than Group I. Specifically, 6 (37.5%) patients at three years and 8 (80%) patients at five years, compared to 2 (13%) patients at three years and 3 (20%) patients at five years in Group I. Additionally, Group II had more fractures at the metal housings in the denture base: 6 (37.5%) patients at the first year, followed by 11 (69%) patients at three years follow-up and 12 (75%) patients at five years, whereas in Group I, 2 (13%) patients in the first year, then at three years, 3 (20%) patients, and at five years, 5 (55%) patients. Regarding reattaching the O-ring to their metal housing, in Group II, 12 (75%) patients required this procedure at three years, and 15 (94%) patients at five years, whereas in Group I, 5 (33%) patients needed this procedure at three years, and 8 (53%) patients at five years. Comparison of the crestal bone loss showed that Group II had significantly more marginal bone loss than Group I. At three years, Group II had vertical bone loss of (3.97±0.16 mm) compared to (2.76±0.15 mm) of Group I, and at 5 years, Group II had (5.01±0.12 mm) compared to (3.41±0.14 mm) in Group I. FEA results revealed statistically significantly less stress concentration around implants in Group I (n=15, 100%) compared to implants in Group II (n=16, 100%), with maximum Von Mises values of 63.30 MPa and 129.94 MPa for vertical and inclined loading in Group I, respectively, and 89.32 MPa and 213.93 MPa for vertical and inclined loading in Group II, respectively. Conclusion: Single implants exhibited more vertical bone loss than two implants, starting three years into service, and their dentures required more repairs and replacements than twoimplant dentures, making their long-term use less economical.

Geometric Path Loss Distributions in Wireless Random Networks: Theory and Applications

Geometric Path Loss Distributions in Wireless Random Networks: Theory and Applications

Influence of blade tip cutting on the flow loss characteristics of side channel pump

A comprehensive analysis of flow loss mechanisms in a side channel pump is put forth in this research. First, the correlation between the cutting angle and loss characteristics in each flow passage of the side channel pump is investigated. Second, the exact regions of the internal loss distributions in the flow passages of the pump are analyzed. Finally, the relationship between the dissipation effect and enstrophy is ascertained among the cutting angles. Generally, the flow loss steadily rises with the increase in cutting angle from 10° to 20° in the impeller. However, at 30°, the losses experience a substantial decrease and then increase thereafter. Meanwhile, the loss gradient in the side channel rises linearly with the increase in cutting angle from 10° to 40°. Cutting angles of 20°, 30°, and 40° revealed the minimum value of energy loss at the outer radius of the impeller compared to the original model. In the side channel passage, all cutting angles revealed a fairly lower magnitude of flow losses than in the original model. Noticeably, the dissipation effect and enstrophy share common resemblances, with a concentration of high enstrophy regions observed in plane 1. The impeller passage portrayed a higher dominancy of the enstrophy region, which nevertheless weakens to a minimum in the side channel for all the cutting angles. The findings of this study provide valuable insights into optimizing the design and performance of side channel pumps.

Microscopic traffic models, accidents, and insurance losses

AbstractThe paper develops a methodology to enable microscopic models of transportation systems to be accessible for a statistical study of traffic accidents. Our approach is intended to permit an understanding not only of historical losses but also of incidents that may occur in altered, potential future systems. Through such a counterfactual analysis, it is possible, from an insurance, but also from an engineering perspective, to assess the impact of changes in the design of vehicles and transport systems in terms of their impact on road safety and functionality.Structurally, we characterize the total loss distribution approximatively as a mean-variance mixture. This also yields valuation procedures that can be used instead of Monte Carlo simulation. Specifically, we construct an implementation based on the open-source traffic simulator SUMO and illustrate the potential of the approach in counterfactual case studies.

Operational Risk Working Party - Validating Operational Risk Models

Abstract Operational Risk is one of the most difficult risks to model. It is a large and diverse category covering anything from cyber losses to mis-selling fines; and from processing errors to HR issues. Data is usually lacking, particularly for low frequency, high impact losses, and consequently there can be a heavy reliance on expert judgement. This paper seeks to help actuaries and other risk professionals tasked with the challenge of validating models of operational risks. It covers the loss distribution and scenario-based approaches most commonly used to model operational risks, as well as Bayesian Networks. It aims to give a comprehensive yet practical guide to how one may validate each of these and provide assurance that the model is appropriate for a firm’s operational risk profile.

Cyber Risk Loss Distribution for Various Scale Drone Delivery Systems

Cyber Risk Loss Distribution for Various Scale Drone Delivery Systems

Development of EPICS-Based Data Acquisition system for Beam Loss Monitor and sX-map

Beam commissioning is underway at KEK’s Superconducting RF Test Facility (STF). Since beam diagnostics are important to realize stable operation, we have developed a time-resolved beam loss distribution monitor as one of the beam diagnostics. This monitor uses up to 16 PIN photodiodes as X-ray sensors to observe X-rays generated due to beam loss of a pulsed beam with a width of approximately 800 μs, which is divided into 100 μs intervals. Thus, 128 data can be acquired per bunch. The data is read out by an EPICS-based data acquisition system. On the other hand, we are also developing an EPICS-based data acquisition system for an inspection method for the superconducting cavities(sX-map) for the vertical test of bare cavities. sX-map strips are inserted inside the stiffener ring at the iris of superconducting cavities. In this presentation, an overview of these EPICS-based data acquisition systems and their integration with the existing control system will be presented.

The Influence of Loss Distribution on the Temperature Field of High-Speed Induction Motor

The Influence of Loss Distribution on the Temperature Field of High-Speed Induction Motor

Analysis of Switched Inductor‐Based High Gain SEPIC for Microgrid Systems

DC microgrids are getting more attention because majority of the renewable energy sources generate DC output voltage and also modern gadgets require DC voltage for its operation. In this work, high gain SEPIC (HGSC) topology is derived from switched inductor voltage boosting cell (SIVBC). The HGSC converter provides continuous source current due to SIVBC and high conversion ratio and achieves maximum efficiency of 97.88% when compared with the existing SEPIC topology. The operating modes, conversion ratio expression, power loss distribution, voltage drop, current stress of the semiconductor devices, and efficiency are also analysed. In DC microgrids, the HGSC intends to track the peak power from solar PV array. An incremental conductance algorithm is employed to track the peak power of the solar PV modules. The power flow in the microgrid system is analysed by employing synchronous reference frame theory‐based current controller. In order to validate the theoretical concepts of the HGSC converter, the hardware model is developed for the load rating of 1,000 W/380 V output voltage.

Performance degradation of steel rebar considering corrosion spatial variability in concrete

The corrosion of steel bars is the main issue affecting the durability of reinforced concrete structures, which is nonuniform owing to the material properties and external environmental effects. In this study, the performance degradation of steel rebars in concrete is estimated considering corrosion spatial variability. With the aid of a three-dimensional measurement technique, a finite element model based on the scanning result was established to examine the corrosion effect on the tensile behaviour of the corroded bars, which was validated with the experimental results and digital image correlation observation. To assess the deformation behaviour of the corroded steels, a semi-analytical model was developed based on the cross-sectional area distribution and material properties. Subsequently, the spatial weight loss distributions with different degrees of corrosion were generated using a random field model. The model parameters were determined by combining engineering judgement and estimation of the experimental results. Finally, probabilistic model of degraded performance was established using the deterministic assessment and simulated steel weight loss distribution.

Parameter identification for standardization of motor loss distribution measurement using thermographic camera

Accurate measurement of the distribution of losses in the motor core is crucial to increase motor efficiency. However, detailed analyses of factors contributing to increased iron losses have not been conducted. Therefore, existing approaches cannot be used as reproducible measurement methods. This study proposes a procedure to measure the loss distribution and identify parameters for improving the reproducibility of measurements. A designer can visualize the iron-loss distribution to compare the actual and designed iron losses and increase the efficiency of the motor. Results indicated that the number of repetitions was a major parameter affecting the measurement accuracy.

A dimension reduction approach for loss valuation in credit risk modeling

This paper addresses the “curse of dimensionality” in the loss valuation of credit risk models. A dimension reduction methodology based on the Bayesian filter and smoother is proposed. This methodology is designed to achieve a fast and accurate loss valuation algorithm in credit risk modeling, but it can also be extended to valuation models of other risk types. The proposed methodology is generic, robust and can easily be implemented. Moreover, the accuracy of the proposed methodology in the estimation of expected loss and value-at-risk (VaR) is illustrated by numerical experiments. The results suggest that, compared to the currently most used Principal Component Analysis (PCA) approach, the proposed methodology provides more accurate estimation of expected loss and VaR of a loss distribution.

Numerical investigation of energy loss distribution in the cavitating wake flow around a cylinder using entropy production method

The wake flow of a circular cylinder is numerically investigated by Large Eddy Simulation (LES) combined with the Schnerr–Sauer cavitation model. By comparing entropy production in the presence or absence of cavitation, the energy loss distribution in the wake flow field of a cylinder is explored, shedding light on the interactions between multiscale vortex systems and cavitation. The comparative results reveal that, under non-cavitating conditions, the energy loss region in the near-wake area is more concentrated and relatively larger. Energy dissipation in the wake flow field occurs in regions characterized by very high velocity gradients, primarily near the upper and lower surfaces of the cylinder near the leading edge. The influence of cavitation bubbles on entropy production is predominantly observed in the trailing-edge region (W1) and the near-wake region (W2). The distribution trends of wall entropy production on the cylinder’s surface are generally consistent in both conditions, with wall entropy production primarily concentrated in regions exhibiting high velocity gradients.

Analysis of Cavitation-Induced Unsteady Flow Conditions in Francis Turbines under High-Load Conditions

Hydraulic vibrations in Francis turbines caused by cavitation profoundly impact the overall hydraulic performance and operational stability. Therefore, to investigate the influence of cavitation phenomena under high-load conditions, a three-dimensional unsteady numerical simulation is carried out for a Francis turbine with different head operating conditions, which is combined with the SST k-w turbulence model and two-phase flow cavitation model to capture the evolution of cavitation under high-load conditions. Additionally, utilizing entropy production theory, the hydraulic losses of the Francis turbine during cavitation development are assessed. Contrary to the pressure-drop method, the entropy production theory can quantitatively reflect the characteristics of the local hydraulic loss distribution, with a calculated error coefficient τ not exceeding 2%. The specific findings include: the primary sources of energy loss inside the turbine are the airfoil cavitation and cavitation vortex rope, constituting 26% and 71% of the total hydraulic losses, respectively. According to the comparison with model tests, the vapor volume fraction (VVF) inside the draft tube fluctuates periodically under high-load conditions, causing low-frequency pressure pulsation in the turbine’s power, flow rate, and other external characteristic parameters at 0.37 Hz, and the runner radial force fluctuates at a frequency of 1.85 Hz.

Index-based insurance to mitigate current and future extreme events financial losses for water utilities

Mitigation and management strategies for extreme weather events become increasingly important for the development and maintenance of society as these events become more frequent and intense. Drought and flood management strategies have focused on structural measures; however, they are not sufficient to prevent water supply disruptions and economic losses. In this concept, adaptation plays the role of anticipating the adverse financial impacts of extreme weather events and taking appropriate measures to minimize them. Therefore, insurance is a valuable adaptation tool to offset unexpected losses and prevent financial damage from turning into long-term economic damage. We simulated multi-year and multi-risk index-based insurance for a Water Supply System, responsible for providing water to 7.2 million people. Our methodology comprises (1) characterizing the indexed variable, (2) calculating economic losses by Loss Distribution Approach (LDA) for current and future periods, and (3) estimating risk premiums based on expected losses of the low, medium, and high coverage levels. Our findings indicate a linear relationship between premium and coverage level, i.e, the higher the premium, the higher the insurance coverage level. We suggested a premium fee for each evaluated scenario, which would be introduced into the water bill as a novel way to pool risk among customers and protect them from surcharge fluctuations.

Numerical Simulation on Microwave Melting of Hastelloy C-276

Melting of metals is of utmost importance in the manufacturing industry as it is the primary manufacturing process to obtain the desired shape and size. microwave melting is a novel technique that uses electromagnetic wave radiation to heat materials. In the present work, the melting of Hastelloy C-276 inside a multimode microwave applicator operating at 2.45 GHz and 900 W input power, is explored in numerical and experimental. This results in a significant reduction in processing time and leads to lesser material wastage. The distribution of temperature, electric field, and resistive losses was analysed to understand the microwave melting of the Hastelloy C-276 sample. The study revealed that the melting time taken was ~440 seconds for microwave melting of Hastelloy C-276.

Kepuasan pasien di jakarta barat terhadap gtsl nilon termoplastik

disorders, and aesthetic function. Partial tooth loss can be overcome by using removable partial dentures (RPD). There are various types of removable partial dentures, one of which is made of thermoplastic nylon. Objectives: To describe patient satisfaction using thermoplastic nylon-based removable partial dentures in West Jakarta. Materials and Methods: a descriptive observational study using a cross-sectional method. 109 Respondent participated in this study. A Validated quesionnaire containing 20 questions was given via Google forms to measure patient satisfaction. Results: 20 questions that have passed the validity and reliability tests, the results show that the age group that uses the most nylon thermoplastic RPD is 36-45 years (42.2%). There were more female respondents than female respondents (67.49%). Most of the denture use time is less than 1 year (56%). The highest distribution of tooth loss was a combination of anterior and posterior teeth (42.2%), front of the maxilla (23.9%), back of the mandible (21.1%), back of the maxilla (11.9) and the least was the front of the mandible (0.9%) ). As many as (1.8%) were dissatisfied, 12.8% were satisfied, and 85.3% were very satisfied with their thermoplastic nylon removable partial denture. Conclusion: 93 respondents were very satisfied with their thermoplastic nylon removable partial dentures.