STUDY OF THE INFLUENCE OF THE EFFICIENCY OF USE OF THE PRODUCTION AREAS OF THE ENTERPRISE ON THE VOLUME OF PRODUCTION

The article considers the method of modeling and factor analysis of the final production result of the enterprise – the volume of production. It is proposed to use deterministic models in the factor analysis of this indicator, which contain the set of factors that reflect the size and efficiency of use of the production areas of the enterprise. The article emphasizes that in the market economy, factor analysis is the important and effective basis for justifying management decisions. The main task of such analysis is the systematic and comprehensive study of the production activities of the enterprise in order to objectively assess the achieved results and establish real ways to further improve its efficiency. Taking this into account, the study of theoretical approaches to the performance of the factor analysis of the efficiency of using the production areas of the enterprise, that is, determining the quantitative influence of factors on the volume of production, is gaining relevance. To study the impact of these factors on the change of this indicator, it is proposed to conduct the step-by-step factor analysis, the essence of which is that the calculation of the impact on the change of the analyzed indicator is first two factors, then three and so on. This allows in each case to calculate the impact on the change of the studied indicator only the factors that are currently the most significant and relevant. The method of factor analysis of production volume given in the article gives the chance to define influence on its change of the most important factors reflecting the sizes and efficiency of use of the industrial areas occupied by the enterprise, to investigate patterns of such influence, to use this information at substantiation of administrative decisions.

The influence of suspension nonlinearities on fatigue assessment of vehicle structure

Load spectrums for the fatigue analysis were created using suspension responses generated in a simulation of vehicle and suspension vertical dynamics nonlinear model for different conditions of vehicle use. The next stage presented was the use of finite element method and analysis of obtained stresses with its transformation to a set of cycles that are used in the determination of fatigue characteristics. The qualitative and quantitative analysis of the stresses field in the vehicle structure and suspension elements was done and later the influence of suspension responses on the fatigue assessment for most loaded parts of suspension and vehicle structure. Lastly conclusions were drawn from the results describing qualitative and quantitative influence of different road class and load conditions on fatigue assessment of vehicle structure and suspension components. Conclusion on the proposed and used methodology also was drawn.

Nonlocal wrinkling instabilities in bilayered systems using peridynamics

Wrinkling instabilities occur when a stiff thin film bonded to an elastic substrate undergoes compression. Regardless of the nature of compression, this phenomenon has been extensively studied through local models based on classical continuum mechanics. However, the experimental behavior is not yet fully understood and the influence of nonlocal effects remains largely unexplored. The objective of this paper is to fill this gap from a computational perspective by investigating nonlocal wrinkling instabilities in a bilayered system. Peridynamics (PD), a nonlocal continuum formulation, serves as a tool to model nonlocal material behavior. This manuscript presents a methodology to precisely predict the critical conditions by employing an eigenvalue analysis. Our results approach the local solution when the nonlocality parameter, the horizon size, approaches zero. An experimentally observed influence of the boundaries on the wave pattern is reproduced with PD simulations which suggests nonlocal material behavior as a physical origin. The results suggest that the level of nonlocality of a material model has quantitative influence on the main wrinkling characteristics, while most trends qualitatively coincide with predictions from the local analytical solution. However, a relation between the film thickness and the critical compression is revealed that is not existent in the local theory. Moreover, an approach to determine the peridynamic material parameters across a material interface is established by introducing an interface weighting factor. This paper, for the first time, shows that adding a nonlocal perspective to the analysis of bilayer wrinkling by using PD can significantly advance our understanding of the phenomenon.

A Case Study of the Impact of Human Resources on Trade Revenues

The quantative and qualitative features of human resources impact the revenue of retail chains. The article’s target of research are ten retail chains with the highest revenue. These are Kaufland Bulgaria, Lidl Bulgaria, Metro Cash & Carry Bulgaria, Billa Bulgaria, Technopolis Bulgaria, Fantastiko, Technomarket Bulgaria, Maxima Bulgaria (Т Market), Zora М.М.С and Praktiker Retail. The subject of research is the quantitative impact of human resources on revenue. The purpose is to outline the trends in employment of human resources and to reveal the quantitative influence of employees’ number and productivity on the revenue and the bottom line of retail chains. The research period is from 2016 to 2018.

Quantitative Influence and Performance Analysis of VR Laparoscopic Surgical Training System

Background VR surgery training becomes a trend in clinical education. Many research papers validate the effectiveness of VR based surgical simulators in training surgeons. However, most existing papers employ subjective methods to study the residents’ surgical skills improvement. Few of them investigates how to substantially improve the surgery skills on specific dimensions.Methods In this paper, we resort to physiological approaches to objectively research quantitative influence and performance analysis of VR laparoscopic surgical training system for medical students. 41 participants were recruited from a pool of medical students. They conducted four pre and post experiments in the training box. In the middle of pre and post experiments, they were trained on VR laparoscopic surgery simulators (VRLS). When conducting pre and post experiments, their operation process and physiological data (heart rate and electroencephalogram) are recorded. Their performance is graded by senior surgeons using newly designed hybrid standards for fundamental tasks and GOALS standards for colon resection tasks. Finally, the participants were required to fill the questionnaires about their cognitive load and flow experience.Results The results show that the VRLS could highly improve medical students' performance (p < 0.01) especially in depth perception and enable the participants to obtain flow experience with a lower cognitive load.Conclusion The performance of participants is negatively correlated with cognitive load through quantitatively physiological analysis. This might provide a new way of assessing skill acquirement.

Analysis and Experimental Verification of Mechanical Errors in Nine-Link Type Double-Toggle Mold/Die Clamping Mechanisms

Nine-link type double-toggle mold/die clamping mechanisms are widely used in modern injection molding machines and die casting machines in order to provide sufficient mold/die clamping force for counteracting the pressure occurred inside molds/dies. In this paper, the analysis and experimental evaluation of mechanical errors in nine-link type double-toggle mold/die clamping mechanisms are presented. The kinematic error equations of the output link (i.e., the moving platen) caused by dimensional errors (or tolerances) of link members are derived analytically through the concept of tolerance sensitivity analysis. Evaluation indices based on the asymmetry of the mold/die clamping mechanism caused by mechanical errors are established. A case study is then given to demonstrate the derived analytical equations and the established evaluation indices. Subsequently, a prototype for performing the experimental evaluation is conceptually designed and was actually constructed. Experiments were conducted for evaluating the quantitative influence of mechanical errors on the operating performance of the constructed mold/die clamping mechanism. According to the experimental results, response surface modelling for benefiting the constructed mold/die clamping mechanism with better operating performance could be performed. The presented research results will be helpful in the tolerance analysis and mechanical error detection of nine-link type double-toggle mold/die clamping mechanisms.