Probabilistic assessment of complex system consisting three subsystems, multi-failure threats and copula repair approach

PurposeThe purpose of this paper is to deliberate the system reliability of a system in combination of three subsystems in a series configuration in which all three subsystems function under a k-out-of-n: G operational scheme. Based on computed results, it has been demonstrated that copula repair is better than general repair for system better performance. The supplementary variable approach with implications of copula distribution has been employed for assessing the system performance.Design/methodology/approachProbabilistic assessment of complex system consisting three subsystems, multi-failure threats and copula repair approach is used in this study. Abbas Jubrin Bin, V.V. Singh, D.K. Rawal, in this research paper, have analyzed a system consisting of three subsystems in a series configuration in which all three subsystems function under a k-out-of-n: G operational scheme. The supplementary variable approach with implications of copula distribution has been employed for assessing the system performance. Based on computed results, it has been demonstrated that copula repair is better than general repair for system better performance.FindingsIn this analysis, four different cases of availability are analysed for Gumbel–Hougaard family copula and also four cases for general repair with similar failure rates are studied. The authors found that when failure rates increase, the system availability decreases, and when the system follows copula repair distribution, the system availability is better than general repair.Research limitations/implicationsThis research may be implemented in various industrial systems where the subsystems are configured under k-out-of-n: G working policy. It is also advisable that copula repair is highly recommended for best performances from the system. On the basis of mean time to system failure (MTSF) computations, the failure rate which affects system failure more needs to be controlled by monitoring, servicing and replacing stratagem.Practical implicationsThis research work has great implications in various industrial systems like power plant systems, nuclear power plant, electricity distributions system, etc. where the k-out-of-n-type of system operation scheme is validated for system operations with the multi-repair.Originality/valueThis work is a new work by authors. In the previously available technical analysis of the system, the researchers have analyzed the repairable system either supplementary variable approach, supplementary variable and system which have two subsystems in a series configuration. This research work analyzed a system with three subsystems with a multi-repair approach and supplementary variables.

Experimental studies of the operation of a frameless building made of thin-gauge structural sections

Light metal structures (LMS) are widely spread in domestic construction industry. A promising direction for the development of LMS includes prefabricated shell structures made of thin-gauge structural sections. The scope and operating conditions of such structures are quite extensive. In this regard, the development of a competent engineering methodology for calculating buildings using thin-gauge structural sections is required. The present paper describes a method for a full-scale testing of a shell building fragment and provides the results of forces and deformations calculated using the experimental model. In addition, an approach to modeling and dimensioning of finite elements for the profiles under consideration is described. The comparative analysis of numerical data and experimental results is performed. The results of the study can be used both for developing recommendations and engineering methods for calculating similar shell buildings and for determining the actual operational scheme for units and elements of the considered structure.

Data assimilation by the variational method with results for the Indian region

ABSTRACT. The variational method for data assimilation as implemented in the operational scheme at ECMWF is briefly presented. The performance of the variational scheme (3D-Var) with respect to tropical cyclones and the Asian summer monsoon is investigated and compared to the Optimum Interpolation scheme. It is found that the analysis of near-surface winds has improved significantly particularly in the vicinity of tropical storms and depressions. The better analyses have led to improvements in the short range forecasts (day 1 to day 3) of such systems. The summer monsoon appears slightly stronger in the 3D-Var analyses, giving enhanced forecast precipitation over the Western Ghats and over large parts of northern India. Only in the latter of these two areas does this verify with observations. The forecasts for India of geopotential, wind and temperature have improved significantly at all forecast ranges, as verified against own analyses. These results are based on 28 cases in two separate 2-week periods.

Operational use of improved CMVs derived from INSAT IR data in NWP Model over Indian region

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Machine Learning Emulation of 3D Cloud Radiative Effects

<p>The treatment of cloud structure in radiation schemes used in operational numerical weather prediction and climate models is often greatly simplified to make them computationally affordable. Here, we propose to correct the current operational scheme ecRad – as used for operational predictions at the European Centre for Medium-Range Weather Forecasts – for 3D cloud radiative effects using computationally cheap neural networks. The 3D cloud radiative effects are learned as the difference between ecRad’s fast Tripleclouds solver that neglects 3D cloud radiative effects, and its SPeedy Algorithm for Radiative TrAnsfer through CloUd Sides (SPARTACUS) solver that includes them but increases the cost of the entire radiation scheme. We find that the emulator increases the overall accuracy for both longwave and shortwave with a negligible impact on the model’s runtime performance.</p>

Analysis of voltage regulation devices.

The paper considers an electrical substation with a voltage of 330/110/35 kV. Means of voltage regulation on the substation autotransformer are investigated. The paper considers the means of voltage regulation on autotransformers of the 330/110/35 kV substation to ensure uninterrupted power supply and the desired voltage level on the busbars of consumers. The choice of the optimal version of the on-load tap-changer of the autotransformer is shown. The electric network with voltage of 110 and 35 kV is considered. The power supply center is substation 330 kV. The connection between voltages is provided by three three-phase autotransformers of the ATDCTN200000/330/110 type. Autotransformers are used instead of three-winding transformers to reduce the cost of conductive material and increase transmission power, but unlike three-winding transformers, they have only one voltage control device - load control regulation. Steady-state and emergency modes are investigated. The PowerFactory program has created a network model, which is used to calculate the mode and evaluate the methods of voltage regulation. On the basis of calculations the point of economic flow distribution in which it is expedient to open a network in a normal mode, and on the switch to provide the device of automatic input of a reserve is defined. The principles of control of modes of operation of electrical systems are investigated: minimum costs for generation, transmission and consumption of electricity (technological losses), reliability of operation of electrical systems, quality of electricity. The purpose of this work is to substantiate the optimal operational scheme of the electrical network, the study of the modes of operation of the 330/110/35 kV network. The simulation of steady and emergency modes is performed in the work. The optimal operational scheme of the electric network is substantiated in order to improve the reliability of power supply and ensure the desired level of voltage on the busbars of consumers.

Emisiones sindicadas de obligaciones como alternativa de financiamiento para las PyME del sector metalmecánico en Guayaquil // Syndicated issues of obligations as a financing alternative for SMEs in the metalworking sector in Guayaquil

Las participación de las pequeñas y medianas empresas (PyMEs) dentro del mercado de valores, fue un objetivo casi inalcanzable, debido a que existían requisitos que en su mayoría no podían cumplirse. Mejía (2007), refiere que los obstáculos para ingresar al mercado de valores, son motivos por los cuales las PyMEs acudan al crédito tradicional como fuente de financiamiento. Es por esto que el presente trabajo tiene como objetivo desarrollar el esquema operativo de las emisiones sindicadas de obligaciones como instrumento financiero, para la PyMEs del sector metalmecánico en Guayaquil, Ecuador. Para cumplir con este objetivo se realizó un estudio descriptivo comparativo utilizando la técnica de encuestas; además, se hizo uso de fuentes secundarias como los portales de web, revisión bibliográfica, entre otros. De los hallazgos se identifica que las PyMEs se financiaban exclusivamente con proveedores, debido a la restricción de los créditos bancarios; sin embargo se ha reconocido otras formas de financiamiento como el mercado de valores de Ecuador. // The participation of Small and Medium Enterprises (SMEs) in the market, was a goal almost unattainable, because there are requirements to be met most of whom could not be fulfilled. Mejia (2007), points out that the obstacles to entering the stock market are the reasons why SMEs ask for traditional credit as a financing source. That is why this paper aims to develop the operational scheme of syndicated issues of obligations as a financial instrument for SMEs in the metalworking sector in Guayaquil, Ecuador. To achieve this objective, a comparative descriptive study was carried out using the survey technique; In addition, secondary sources such as web portals, bibliographic review, and others were used. The findings identify that SMEs were financed exclusively from suppliers, due to the restriction of bank loans; however, other forms of financing have been recognized, such as the Ecuadorian stock market.