In this paper, we introduce an approximate approach to public service system design making use of a universal IP-solver. The solved problem consists in minimization of the total discomfort of system users, which is usually proportional to the sum of demand-weighted distances between users and the nearest source of provided service. Presented approach is based on radial formulation. The disutility values are estimated by some upper and lower bounds given by so-called dividing points. Deployment of dividing points influences the solution accuracy. The process of the dividing point deployment is based on the idea that some disutility values can be considered relevant and are expected to obtain in the optimal solution. Hereby, we study various approaches to the relevance with their impact on the accuracy and computational time

The reorganization of an emergency medical system means that we look for new locations of ambulance stations with the aim of improving the accessibility of the service. We applied two tools that are well known in the operations research community, namely mathematical programming, and computer simulation. Using the hierarchical pq-median model, we proposed optimal locations of the stations throughout the country and within large towns. Several solutions have been calculated that differ in the number of stations that are supposed to be relocated to new positions. The locations proposed by the mathematical programming model were evaluated via computer simulation. The approach was demonstrated under the conditions of the Slovak Republic using real historical data on ambulance dispatches. We have concluded that (i) the distribution of the stations proposed by the hierarchical pq-median model overcomes the current distribution; the performance of the system has significantly improved even if only 10% of the stations are relocated to new municipalities; (ii) the variant that relocates 40% of the stations is a reasonable compromise between the benefits and induced costs; (iii) optimizing station locations in big towns can significantly improve the local as well as the nationwide performance indicators; the response times in two regional capitals has reduced by more than 4 min.

The performance of the database system significantly influences the whole ecosystem reflected by the applications, information systems, and analytical tools. Data retrieval and access form crucial operations. Data indexing can provide additional power for the tuple location, identification, and proper management. By using such a technique, Select statement can benefit. Data integrity and consistency can be ensured, as well. On the other hand, adding new indexes brings additional demands on the system and change operations, whereas activity performed on the data must be mirrored into the indexes to ensure correctness and recency. This paper deals with the index definition from the data manipulation operation perspective. New modules monitoring changes are added. As a result, the amount of the indexes can be significantly increased, but with minimal impact on the Insert, Update, and Delete statements.