Employers signal difficulties in sourcing technically-educated staff. They often engage, though to a limited degree, in cooperation with vocational schools to mitigate this difficulty. One of the reasons for the limited involvement of enterprises in cooperation with schools is the difficulty in assessing the benefits that it may bring. The aim of the study in the article was to develop and initially verify a model for evaluating the results of supporting secondary technical schools by manufacturing enterprises. The article features a multiple case study using several types of interviews, a distributed questionnaire and an analysis of secondary sources. The study was conducted in cooperation with four large manufacturing enterprises. The result of the research is a more thorough understanding of the possibilities and limitations in evaluating the results of support for schools. This support should translate in enterprises into more effective and efficient management of the competences of the future.

The growing population and the development of industries in all countries of the world have created a very important and complex issue for water supply to cities. Today, many parts of the world are facing the problem of water shortage and this problem cannot be easily solved. In addition to the proper use of water resources and preventing the loss of natural water, the establishment of regional water supply networks is effective in meeting the future needs of the people. A water distribution network (water supply network) is a set of interconnected pipelines used to transport and distribute water in a complex. In designing the water distribution network, factors such as the type of water distribution network, water pressure, water velocity, design flow, minimum pipe diameter, pipe material and many other factors should be considered. In this study, we have tried to design the water supply network of a part of Balikpapan city in Indonesia. The design method led to the determination of pressure values in the connection nodes, pipe diameters, flow rate and velocity in the pipes. All the existing criteria are considered in the design of the water supply network. Although this study has been implemented for a specific study area, it can be of great help to designers in designing the water supply network.

The supply chain of spare parts is the intersection between the supply chain, the after-sales

and the maintenance services. Some authors have tried to define improvement paths in terms

of models to satisfy the performance criteria. In addition, other authors are directed towards

the integration of risk management in the demand forecasting and the stock management

(performance evaluation) through probabilistic models. Among these models, the probabilistic

graphical models are the most used, for example, Bayesian networks and petri nets.

Performance evaluation is done through performance indicators.

To measure the appreciation of the supply of the spare parts stock, this paper focuses on the

performance evaluation of the system by petri nets. This evaluation will be done through

an analytical study. The purpose of this study is to evaluate and analyze the performance of

the system by proposed indicators. First, we present a literature review on Petri nets which

is the essential tool in our modeling. Secondly, we present in the third section the analytical

study of the model based on bath deterministic and stochastic petri networks. Finally, we

present an analysis of the proposed model compared to the existing ones.