Probabilistic structural mechanics research for parallel processing computers

Aerospace structures and spacecraft are a complex assemblage of structural components that are subjected to a variety of complex, cyclic, and transient loading conditions. Significant modeling uncertainties are present in these structures, in addition to the inherent randomness of material properties and loads. To properly account for these uncertainties in evaluating and assessing the reliability of these components and structures, probabilistic structural mechanics (PSM) procedures must be used. Much research has focused on basic theory development and the development of approximate analytic solution methods in random vibrations and structural reliability. Practical application of PSM methods was hampered by their computationally intense nature. Solution of PSM problems requires repeated analyses of structures that are often large, and exhibit nonlinear and/or dynamic response behavior. These methods are all inherently parallel and ideally suited to implementation on parallel processing computers. New hardware architectures and innovative control software and solution methodologies are needed to make solution of large scale PSM problems practical

Theoretical and methodological approaches to assessing the safety and reliability of accounting and analytical information in the system of economic security of enterprises

Subject of research is theoretical and practical aspects of accounting and analytical information in the system of economic security. Subject area is focused on ensuring reliability and accuracy of accounting and analytical information in management decisions towards economic security of entities. Aim of research is to highlight the key features of accounting and analytical information, development of methods for evaluating the reliability and accuracy of accounting and analytical information in the system of economic security of entities in terms of innovation and investment phase of economic development. Research objectives consist in identifying prospects for development of management accounting in the context of accounting and analytical security activities, research characteristics of accounting and analytical information decomposition factors that ensure the quality of accounting and analytical information systems for economic security of businesses and developing methodologies for evaluating the integral quality factor accounting and analytical information in decision-making in the system of economic security of entities. Hypothesis of research is based on the assumption that management efficiency in management decisions to ensure economic security businesses require reliable, accurate and timely information, which is formed in accounting and analytical system. Methodology is based on the methods of theoretical and empirical research, deductive, abstraction, formalization, statistical methods. Survey of 125 respondents from industry enterprises of Kharkiv Region. Data was collected through direct survey during preparation of Kharkiv Region Development Strategy for the period until 2020. Respondents were asked a number of questions that determine the purposes and directions of development of managerial accounting as an information platform in management decisions of economic security. Based on the structural approach was performed decomposition of the factors that ensure the quality of accounting information systems for economic security of entities. On the basis of additive reduction developed and offered method of estimating the integral quality factor of accounting and analytical information of entities in the system of economic security of entities. Conclusion. Research confirmed the role and importance of accounting and analytical management accounting information in making management decisions in the system of economic security. According to the results, was performed decomposition of the factors that ensure the quality of accounting and analytical information systems for economic security of entities and the proposed method of estimating the integral index of quality accounting and analytical information in decision-making in the system of economic security of entities. Practical implications. Decomposition of the factors that ensure the quality of accounting information useful in the construction of an integrated accounting and analytical system of individual enterprise. Methods of assessing the quality of accounting and analytical information can be used during certain control measures within the decision-making system of economic security and modified for individual undertakings in accordance with the specific activities and class of management tasks. Value/originality. Coverage of the main objectives and perspectives of management accounting in the context of accounting and analytical security proves that the information is in demand at the level of top management in strategic decision-making, and at the level of middle management in decision-making and tactical control measures

Long-Term Scintillation Studies of Pulsars: III. Testing Theoretical Models of Refractive Scintillation

Refractive interstellar scintillation (RISS) is thought to be the cause behind a variety of phenomena seen at radio wavelengths in pulsars and compact radio sources. Though there is substantial observational data to support several consequences of it, the quantitative predictions from theories have not been thoroughly tested. In this paper, data from our long-term scintillation study of 18 pulsars are used to test the predictions. The fluctuations of decorrelation bandwidth ($\nu_d$), scintillation time scale ($\tau_d$) and flux density (F) are examined for their cross-correlations and compared with the predictions. The theory predicts a strong correlation between $\nu_d$ and $\tau_d$, and strong anti-correlations between $\nu_d$ and F, and $\tau_d$ and F. For 5 pulsars, we see a reasonable agreement. There is considerable difficulty in reconciling the results for the rest of the pulsars. Our analysis shows the underlying noise sources can sometimes reduce the correlation, but cannot cause an absence of correlation. It is also unlikely that the poor flux correlations arise from a hitherto unrecognized intrinsic flux variations. For PSR B0834+06, which shows anomalous behaviour of persistent drift slopes, positive correlation is found between $\tau_d$ and the drift-corrected $\nu_d$. Many pulsars show an anti-correlation between $\nu_d$ and the drift slope, and this is in accordance with the simple models of RISS. The detections of correlated variations of observables and a reasonable agreement between the predicted and measured correlations for some pulsars confirm RISS as the primary cause of the observed fluctuations. However, the complexity seen with the detailed results suggests the necessity of more comprehensive theoretical treatments for describing refractive fluctuations and their correlations.Comment: 27 pages, 6 Figures, 6 Tables. Accepted for publication in The Astrophysical Journa

A comparison of missing value imputation methods applied to daily precipitation in a semi-arid and a humid region of Mexico

[Abstract:] Climatological data with unreliable or missing values is an important area of research, and multiple methods are available to fill in missing data and evaluate data quality. Our study aims to compare the performance of different methods for estimating missing values explicitly designed for precipitation and multipurpose hydrological data. The climate variable used for the analysis was daily precipitation. We considered two different climate and orographic regions to evaluate the effects of altitude, precipitation regime, and percentage of missing data on the Mean Absolute Error of imputed values and performed a homogeneity evaluation of meteorological stations. We excluded meteorological stations with more than 25% missing data from the analysis. In the semi-arid region, ReddPrec (optimal for nine stations) and GCIDW (optimal for eight stations) were the best-performing methods for the 23 stations, with average MAE values of 1.63 mm/day and 1.46 mm/day, respectively. In the humid region, GCIDW was optimal in ~59% of stations, EM in ~24%, and ReddPrec in ~17%, with average MAE values of ~6.0 mm/day, 6.5 mm/day, and ~9.8 mm/day, respectively. This research makes a valuable contribution to identifying the most appropriate methods to impute daily precipitation in different climatic regions of Mexico based on efficiency indicators and homogeneity evaluation.Consejo Nacional de Ciencia y Tecnología (CONACYT), Mexico; 1015533The authors thank two anonymous reviewers and an associate editor for their objective comments and constructive criticism, which helped to improve the quality of this paper. In addition, J.M.N.C thanks the Consejo Nacional de Ciencia y Tecnología (CONACYT) of Mexico for financial support throughout the Doctoral Program of Ciencia y Tecnología del Agua, Grant No. 1015533, Universidad de Guanajuato and Universidad Central “Marta Abreu” de las Villas

A Ground-based L-band Radar System for Monitoring Forest Temporal Dynamics

L-band FMCW radar is implemented for monitoring forest dynamics. It took short-term and long-term measurements with an internal calibration system that guarantees stability and precision. The radar data is compared to in-situ measurement, which infers causal relationships between radar backscatter signal and forest physiology index such as tree dielectric. This paper explains the relationship between radar signals and environmental components such as precipitation based on the measurement. The radar demonstrates some interesting observations, for example, trees\u27 daily activity and freeze-thaw process

Some properties of a 5-parameter bivariate probability distribution

A five-parameter bivariate gamma distribution having two shape parameters, two location parameters and a correlation parameter was developed. This more general bivariate gamma distribution reduces to the known four-parameter distribution. The five-parameter distribution gives a better fit to the gust data. The statistical properties of this general bivariate gamma distribution and a hypothesis test were investigated. Although these developments have come too late in the Shuttle program to be used directly as design criteria for ascent wind gust loads, the new wind gust model has helped to explain the wind profile conditions which cause large dynamic loads. Other potential applications of the newly developed five-parameter bivariate gamma distribution are in the areas of reliability theory, signal noise, and vibration mechanics

Impact of Human Resources Management practices on Achieving competitive Advantage for Industrial companies (An Empirical study at Al Hassan Industrial Estate-Jordan)

The purpose of this study is to examine the impact of Human Resources Management practices on achieving competitive Advantage for industrial companies at al Hassan industrial Estate. The variables of this study consisted of independent Variable (Human resources management practices), and the dependent variable (achieving competitive advantage). The study employed the statistical analytical descriptive approach based on the literature review and field work to discuss hypothesis. The population of this study consisted of (40) industrial company located in Al Hassan industrial estate – Irbid – Jordan. The study adopted purposive sample which is included all directors of Human resources department in the Industrial companies that the sample included. The sample totaled (40) Human resources directors. The study used questionnaire as a tool to collect data and to measure study samples individuals attitudes towards the impact of Human resources practices on achieving competitive advantage and to clarity the importance of its practices for companies’ success. The findings indicated that there is positive correlation with statistical significant at significant level (0.05> ? ) among sample individual attitudes toward all dimensions of independent variable and dependent variable. The findings also indicated that there is high impact and prediction capacity for each of the independent variable dimensions on dependent variable. Major findings of this study indicated that there is a strong effect of selecting and placement on achieving competitive advantage. The other dimensions of human resources management practices as job analyses and design, recruitment, training and development and employees performance appraisal shows that there is no significant impact on achieving competitive advantage. The study recommends that business organizations have to apply and pay more attention to all human resources management functions in parallel Keywords: HRM, Job analysis and design, Recruitment selection and placement, Training and development, performance Appraisal, Competitive advantage