Zorica Veljkovic

Some coincidence and common fixed point theorems for ordered Prešić-Reich type contractions

The purpose of this paper is to prove some coincidence and common fixed point theorems for ordered Prešić-Reich type contractions in ordered metric spaces. Results of this paper generalize and extend several known results from metric spaces into product spaces when the underlying space is an ordered metric space. An example illustrates the case when new results can be applied while old ones cannot.

Serbian and Libyan Female Drivers’ Anthropometric Measurements in the Light of the Third Autonomy Level Vehicles

At level 3 the driver still remains “in-the-loop” due to the inability of the automated system to manage a particular driving situation/environment and anthropometric data are still essential in design. In that aim anthropometric measurements of 193 Serbian and 50 Libyan female drivers have been collected using standard anthropometric instruments and compared using statistical methods - descriptive statistics with Kolmogorov test for normality, linear regression and correlation analysis and comparison of measured anthropometrics using z test. Results obtained in this study are useful to passenger car designers aimed to compete on autonomy level 3 and show that there exist significant differences between Serbian and Libyan female drivers. Future research on other rarely available anthropometric data for other nationalities is recommended, due to globalization trends and constant migrations.

Interfaces for Distributed Remote User Controlled Manufacturing as Collaborative Environment

Recent advances in information and communication technologies that support the concept of collaborative networks have allowed manufacturing enterprises to use remotely controlled decentralized manufacturing processes. This survey is based on the experiment that involved 34 small collaborative groups at Serbia, that have used the interface for remote collaborative control of manufacturing systems to control of CNC machine located in Portugal. The experiments on collaborative environment are done using two types of “client” user interface, “Wall” and “Window”. Measured characteristics included: collaborative effort, involvement, awareness, representational fidelity features and co-presence. Results show that “Wall” interface has higher values of index of interdependence of collaborative virtual environment characteristics. Conclusion is that characteristics of collaborative environment are less interdependent when “Window” is used opposite to the “Wall” interface. Future research ideas are to test similar platforms with more users and to study aspects such as group leader choice and role, possible conflicts etc.

Group Characteristics and Task Accuracy in Distributed Remote User Controlled Manufacturing as Collaborative Environment

Collaborative environments today are very successful when used in multiplayer games and for meetings organizing, which gives an idea to explore its potentials in remotely controlled decentralized manufacturing. This survey is based on the experiment that involved 34 small collaborative groups including 68 students in Serbia, that have used the interface for remote collaborative control of manufacturing systems to control of CNC machine located in Portugal. Our previous surveys have shown that group work consumes less time than individual work in most working options. This paper examines influence of homogeneity of the groups. Results of statistical examination show that percentages of errors are significantly or highly significantly higher in homogeneous compared to a non-homogeneous groups. Therefore, it could be recommended to form heterogeneous groups when remotely controlling decentralized manufacturing processes.