An extensive study was made on the tribological behavior of the contact of the precessional transmission (PT) gear. The research was carried out on tribomodels at an SMT-1 type installation according to a methodology previously developed by the authors. The concave-convex contact of teeths of the PT was simulated in the non-conformist research by contact between two cylindrical rollers with different diameters. The cylindrical rollers were made from the materials taken in the study. In the framework of the experimental research, based on a study carried out by the authors, were used metallic and plastic materials, recommended for the design and manufacture of gear wheels. Obtained research results, allowed the choice of the materials for the gear wheels manufacturing for PT and the lubrication type from the point of view of the tribological behavior of the contact (according to the anti-friction criterion).

For the first time, the gear contacts of the precessional transmission were subjected to experimental research, on tribomodels, using metallic (steel 40Cr) and polymeric (POM) material couplings in various combinations: steel 40Cr/steel 40Cr, POM/POM and POM/steel 40Cr. The experiments were carried out in conditions without contact lubrication and lubrication (MULTIS EP2). The samples - model, in the form of cylindrical rollers were manufactured from tested materials, with the dimensions established from the conditions of ensuring the geometric and kinematic equivalence of the contact of the precessional gear. The research methodology consists in the loading of the contact in steps with the normal force (Fn) for periods of time determined by the stabilization of the tribological characteristics, especially the temperature T generated by the friction process. The tribological behavior of the contact was determined by the evolutions in time of: the frictional torque (Mf), the temperature in the contact area (T), the friction force (Ffr) and the summary friction coefficient (fƩ). The purpose of the research was to experimentally establish the influence of the geometry and kinematics of the contact on the friction process and the tribological behavior of the couplings of materials under study, in the operating conditions of the contact without lubrication and with lubrication. The results of testing on tribomodels, according to the methodology proposed by experimental research, can be successfully applied to the design stage of Precessional Transmission (PT) gears.

This paper deals with the theoretical-experimental model of the tribological behavior of the contact elements in precessional gears (PG) in the functions of conjugate profiles of linear velocities “convex-concave” or “convex-convex” for the corresponding geometric parameters (ρki, r, ρki – r) and the values of the kinematic force parameters (VE1, VE2, Vai) for each concrete position of the ki points. The calculation of the constructive-functional and kinematic parameters of the “roller-shoe” and “roller-roller” elements of the tribocouple were adjusted for the experimental verification tests on the SMT-1 installation and adapted to the specific test conditions of the tribocouples with conformal contact of gear teeth made of plastics, which will be subjected to sliding friction and rolling processes of the concrete tribocouple elements.

The paper addresses the issue of the influence that the law of friction has on the dynamic behavior of the mechanical system that interacts with a tribosystem. The emergence of certain nonlinearities of higher order into the law of friction leads to an intensification of the dissipative process and to tribosystem destabilization. Consequently, friction excited self-oscillations are generated into the elements of the mechanical system with a wide spectrum of frequencies, sustained from the external source of energy. The theoretical and experimental modelling of the dissipative process and of the generation of is based on the frictional harmonic oscillator that interacts with the tribosystem. The oscillator is used as a sensitive element to the fluctuations of the frictional force and as a measure of the dissipated energy. Starting from the model, the elaboration of a method and of devices for experimental research provided the opportunity to study the behavior of the tribosystem in unstable operating.

The complexity of information security does not resume to mere technicality, transferring significant liability to proper management. Risk analysis in information security is a powerful tool that comes in handy for managers in making decisions about the implementation of efficient information management systems, in order to achieve the organization's mission. As a part of risk management, risk analysis is the systematic implementation of methods, techniques and management practices to assess the context, identify, analyze, evaluate, treat, monitor and communicate the risks for the information security and systems through which they are processed, stored or transmitted. The ISO/IEC 27005:2011 – Information security risk management, does not specify any particular method for managing the risks associated with information security, but a general approach. It is up to the organization to devise control objectives that would reflect specific approaches to risk management and the degree of assurance required. There are several models, methodologies and tools amongst which those like CRAMM (United Kingdom, Insight Consulting), Risicare/Mehari (France, Clusif), GSTool (Germany, ITGrundschutz). The theoretical model of the mentioned methodologies is hard to put in practice without experience required from the members of the risk analysis team. Using the appropriate risk assessment solution, an organization can devise its own security requirements.

The paper addresses the issue of the influence that the law of friction has on the dynamic behavior of the mechanical system that interacts with a tribosystem. The emergence of certain nonlinearities of higher order into the law of friction leads to an intensification of the dissipative process and to tribosystem destabilization. Consequently, friction excited self-oscillations are generated into the elements of the mechanical system with a wide spectrum of frequencies, sustained from the external source of energy. The theoretical and experimental modelling of the dissipative process and of the generation of is based on the frictional harmonic oscillator that interacts with the tribosystem. The oscillator is used as a sensitive element to the fluctuations of the frictional force and as a measure of the dissipated energy. Starting from the model, the elaboration of a method and of devices for experimental research provided the opportunity to study the behavior of the tribosystem in unstable operating

The present paper treats certain methodological aspects of researching the behaviour of the sliding tribosystem in cyclical translation motion from the point of view of the dynamics of contact processes. The dynamic effect is manifested by a fluctuating character of the dynamic variables with intermittency type evolution. The fluctuating character of contact processes imposes peculiar conditions in selecting systems of measurement, acquisition and processing dynamic variable signals of the system. In order to extract the fluctuation signal of contact interaction forces the elastic oscillator is used. The processing of the signals emitted by the tribosystem is made on the basis of FNS (Flicker-Noise Spectroscopy) methodology.

The classical problems of concurrent programming start from the design problems of operating systems in the 80-s. But today there are still proposed new solutions for these problems with the help of various design and programming approaches. The present article describes a solution which was designed according to some new object-oriented principles, based on design patterns and proposes two program solutions: firstly - an object-oriented implementation in Java language, the secondly - an aspect-oriented one in AspectJ language.