Introduction: Noise represent an unwanted sound that endangers human health in multiple manners and in work setting causes reduction of productivity on one side, and increased waste on the other. Noise pollution occurs when the ear is exposed to the volume of sound that is disturbing, stressful or directly damaging hearing, but also acting on the organism as a whole. Aim: The aim of the article is to examine the vulnerability of workers working on the „press“ machine, and to carry out an analysis and examine the press operator workplace, then perform the noise spread measurement in the press operator work area and compare the current measurements with the permissible levels and analyze the time period of worker exposure, as well as presentation of the effects of noise on productivity and workers health. The aim of the article also includes the proposal for decrease of noise pollution. Methods: A noise analysis at the workplace of workers working on a „press“ machine was performed, which is exposed to a high impulse noise due to which the quality and quantity of production are reduced. For the purpose of calculating the noise level for one working day at the press operator site 1, 2 and 3, it is necessary to analyze the noise level in time. Operators spend most of their working hours at stations 1 and 3 where the measured noise level is Lm1 = 94.7 dB is taken, or at position 3, Lm3 = 97.2 dB. The measured noise level at these locations without the operation of the press is Lm1 = 80.1 dB, or at station 3 is Lm3 = 80.1 dB. Results: It was found that these operators working on the machine in question were exposed to a noise over the limit for more than three years. Their health problems that arise as a result of noise exposure are documented in their health charts. In order to achieve uninterrupted work at the press machine, during the eight hours shift, a noise correction is required to allow the equivalent sound level to fall within one day to the permissible 85 dB. In this regard, we consider the fact that we have known that the press produces a sound level of 110 dB, and that there is a reverberation (reflecting) sound. Given the technical characteristics of the plant, the reduction of the sound intensity of the source itself is not possible, so the suggestions of the technical solution will be based on reduced reflected sounds and to prevent the spread of direct sound to the operator. Conclusion: Workers are exposed to permanent noise during a working day, which produces a number of consequences for the health of the worker, but also the employer and the community. The imperative of the employer is to reduce the number of rejects, increase profitability and to have a positive impact on the health of the individual.

The problem related to the inadequate position of workers during lifting heavy loads is the everyday life of many environments, such as industrial halls or warehouses, which often results in the deepening of the worker's spine load problem. An analysis of such a workplace was carried out in this paper. The workloads at specific body zones were determined, whether they were within the prescribed limits or exceeded it, and on that basis a redesign of the workspace was made in accordance to the anthropological values of the model.

In this paper we present an analysis of a cluster based inference in a particular computer network. The faculty forum on a real community server, where students and stuff share their knowledge and experiences, is used for this purpose. In order to better understand the structure of the network, we represent it as a graph, where vertices are represented by the members of the forum and the edges act as the links between the forum posts. As in many similar systems, this forum is organized in threads that are divided into sections (subjects), and sections are divided into groups (academic years). It is shown that the resulting network exhibits a scale-free distribution with large clustering coefficients following the small-world properties. As the clusters hold some important information about the nature of the network, we developed a special software agent that explores the background SQL database and automatically acquires the relevant information. Based on this data, detailed information including the graphs degree distribution, clustering coefficient, Laplacian, and normalized Laplacian eigenvectors and average distance are calculated. The resulting analysis gives us a better understanding of the nature of this particular network, which can be valuable information for the administrators.

A basic problem in robotics, especially in advanced graphical simulation systems, consists of solving a problem of finding an optimal path for moving robotic objects from a known starting position to a goal point. This problem is generally complex and it is usually associated with artificial intelligence and advanced numerical computations. Standard algorithms such are A*, Dijkstra's algorithm, genetic algorithms or breadth-first search are among the most popular for such problems. In this paper we present a graphical simulation system in 2D that effectively solves a path finding problem based on a well known A* algorithm. A* algorithm is used because of its popularity, flexibility and the fact that can be applied in a wide range of contexts. The programming is done in the C# language under the latest .NET 2.0 framework. The resulting software is tested on number of different configurations and optimal solutions are found quickly and effectively. It is shown however, that if the heuristic is not admissible, the applied algorithm cannot guarantee the minimal distance.

Abstract Some analytical models of vibrating systems may be expressed as a linear combination of known connectivity matrices. The connectivity matrices depend on the modelling method and the order of the approximation chosen, while the combination factors are determined by the physical parameters of the system. The physical parameters of such models can be identified from a single natural frequency, two mode shapes and a static deflection due to a unit load. It is shown that the identification process is determined by the solution of a certain generalised eigenvalue problem, where the physical parameter vector is proportional to one of its eigenvectors. It thus follows that generally for an n -degree-of-freedom (dof) system there are n possible solutions. Realisable solutions, however, correspond only to eigenvectors with no sign change in their entries and no vanishing elements, which limits the number of possible physical solutions. The results are demonstrated by an analytical example of an axially vibrating rod and a numerical solution for a Bernoulli–Euler beam.