Maja Vlatkovic

Mrs. Maja Vlatkovic

University of Rijeka, Faculty of Engineering, Rijeka, Primorsko-Goranska Županija, Croatia
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Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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24 June 2022 in Metals
Verified
Journal Article
Open access
PDF file
MVMaja Vlatkovic
Maja Vlatkovic
DPDuško Pavletić
Duško Pavletić
David IštokovićDavid Ištoković
David Ištoković
Marko FabićMarko Fabić
Marko Fabić
Quality control of welded joint is an indispensable part of the welding production process. As part of spot resistance welding group, cross-wire welding process showed great application for welding of products for everyday usage. The non-contact quality control checking is fit for purpose due to specific characteristics of welded products that consist of two cross welded wires or a combination of wires and strips. This work proposes a new method for detecting and measuring of required dimensional parameters, but also founds its applicability for other products if required. A crucial parameter of this research is the height of welded joint, which is necessary for calculating the penetration of the wire into the wire. The proposed measuring method with a reconfigurable measuring system is explained in this paper. The main component of this system is using a machine vision system, which has become an indispensable part of industrial metrology and is considered one of the industry 4.0 concepts. The calibration process for such systems could be very complicated. This work shows an elaborated calibration procedure for this kind of measuring system with referenced standards made for this purpose. Measurement results are compared with ones obtained by conventional method. The focus of vision system is a substantial part as it dictates the quality of the system. This research is done within the project in collaboration with the industrial sector and all samples are from real processes. The results of measured penetration on one product group are showing the applicability of a reconfigurable measuring system in the welding sector, and demonstrate that measurement of welding penetration based on machine vision is feasible and can ensure accuracy.

1 April 2021 in Ships and Offshore Structures
Verified
Journal Article
Closed access
DRDenis Rabar
Denis Rabar
DPDuško Pavletić
Duško Pavletić
SDSandro Doboviček
Sandro Doboviček
MVMaja Vlatkovic
Maja Vlatkovic
The aim of this paper is to introduce a multi criteria performance measurement model for newbuilding dry-docking purposes as a managerial tool. The dry-docking is presented as a process with multiple inputs and outputs, containing various technical and cost data related to the dry-docking project. The data envelopment analysis models with constant and variable returns to scale were used in this research along with the efficiency decomposition method to determine possible sources of inefficiency on the data sets available. The seven criteria to be used for dry-docking performance measurement. Research results determined the best practice/efficient vessels which create the efficient frontier. Projections to the efficient frontier, efficiency decomposition and sources of inefficiency recognition with improvement propositions were provided for the inefficient vessels. Due to the performance assessment carried out, the results represent benchmarks for dry-docking performance and a guideline to future dry-docking improvements on data set researched.

11 May 2022 in Tehnički glasnik
Verified
Journal Article
Closed access
PDF file
IČIvana Čabrijan
Ivana Čabrijan
DVDomagoj Vrtovšnik
Domagoj Vrtovšnik
MVMaja Vlatkovic
Maja Vlatkovic
DPDuško Pavletić
Duško Pavletić
The research paper was prepared within the framework of a project whose aim is to improve the durability of the corrosion protection properties of the product by regulating the input parameters of the cross-wire welding process. Cross-wire welding is a subtype of electric resistance welding. Products made by the cross-wire welding process are widely used in everyday life and can be found in the form of grids, gratings, fencing systems, baskets, guards, etc. The subject of the research work is a preliminary analysis of the stability of the cross-wire welding process. The results of the performed analysis will serve as a starting point for the second phase of the project. Since the recorded values of the set down output parameter differ significantly from the expected values, this parameter is considered as an indicator of the process stability. From the specific trend of the results in the performed analysis, it was concluded that the position of the electrode has a significant influence on the result, which was confirmed by comparing the test results before and after the preliminary tests.