This paper discusses the problems associated with the negative effects that accompany blasting operations, and the certain conclusions were derived. One of the negative effects of blasting operations is the phenomenon of seismic action and its effects on the buildings and the environment. Shock waves, induced by blasting, could cause damages to the building facilities and the environment. Those shocks seem to be very unfavorable to both humans and the environment. Therefore, certain standards were developed that define permissible values of impacts on buildings and people in buildings. In Serbia, there are no standards for assessing the impact of such shock waves. The international regulations and standards, mostly Russian and German, will be used to solve this problem. This case study provides an overview the measurement of shock waves during blasting at the open pit Manastiriste near Topola in a function of the quantity of used explosives, their impact on the surrounding buildings with special reference to the Monastery of the Holy Archangel Michael, as well as the assessment of measurement results according to the appropriate scales in the world. Keywords blasting, shock waves, measurement, impact, seismics * University of Belgrade, Faculty of Mining and Geology, Djusina 7, 11000 Belgrade, Serbia, e-mail: sanjabajic@sezampro.com; radmila.gacina@rgf.rs; katarina.urosevic@rgf.rs; suzana.lutovac@rgf.bg.ac.rs

The aim of this paper is to report primary changes in the market concerning public relations and atmosphere in stores. This study examines the impact of public relations and various dimensions (factors) of the atmosphere on creation (formation) of the purchase decision. The aims of study were: determine in which way the atmosphere affects the purchase decision; research and specify which kind of atmosphere at the sale point positively influences the purchase decision; research and specify the level of consumer’s satisfaction with the atmosphere in the store. The sample of 200 buyers was chosen on the basis of geographical zone of sampling procedure in Bosnia and Herzegovina. Results show that in most dimensions (factors) creation (formation) of the atmosphere in the store influences significantly on the purchase decision. Furthermore, many dimensions (factors) of the atmosphere were found that affect significantly differently on the purchase decision. The results of this research may be of particular interest to those who organized retail stores.

The paper shows an example of performed optimization of sizes in terms of welding costs in a characteristic loaded welded joint. Hence, in the first stage, the variables and constant parameters are defined, and mathematical shape of the optimization function is determined. The following stage of the procedure defines and places the most important constraint functions that limit the design of structures, that the technologist and the designer should take into account. Subsequently, a mathematical optimization model of the problem is derived, that is efficiently solved by a proposed method of geometric programming. Further, a mathematically based thorough optimization algorithm is developed of the proposed method, with a main set of equations defining the problem that are valid under certain conditions. Thus, the primary task of optimization is reduced to the dual task through a corresponding function, which is easier to solve than the primary task of the optimized objective function. The main reason for this is a derived set of linear equations. Apparently, a correlation is used between the optimal primary vector that minimizes the objective function and the dual vector that maximizes the dual function. The method is illustrated on a computational practical example with a different number of constraint functions. It is shown that for the case of a lower level of complexity, a solution is reached through an appropriate maximization of the dual function by mathematical analysis and differential calculus.

In this article we argue that the research on group recommender systems must look more carefully at group dynamics in decision making in order to produce technologies that will be truly beneficial for users. Hence, we illustrate a user study method aimed at observing and measuring the evolution of user preferences and actions in a tourism decision making task: finding a destination to visit. We discuss the benefits and caveats of such an observational study method and we present the implications that the derived data and findings may have on the design of interactive group recommender systems.