Early Highway Construction Cost Estimation: Selection of Key Cost Drivers

Cost estimates in the early stages of project development are essential for making the right decisions, but they are a huge challenge and risk for owners and potential contractors due to limited information about the characteristics of a future highway project. Whereas previous studies were mainly focused on achieving the highest possible estimation accuracy, this paper aims to propose cost-estimation models that can provide satisfactory accuracy with the least possible effort and to compare the perspectives of owners and contractors as the key stakeholders on projects. To determine cost drivers (CDs) that have a high influence on highway-construction costs and require low effort for their establishment, a questionnaire survey was conducted. Based on the key stakeholders' perceptions and collected data set, cost-estimation models were developed using multiple-regression analysis, artificial neural networks, and XGBoost. The results show that reasonable cost-estimation accuracy can be achieved with relatively low effort for three CDs for the owners' perspective and five CDs for the contractors' perspective. Additional inclusion of input CDs in models does not necessarily imply an increase in accuracy. Also, the questionnaire results show that owners are more concerned about environmental issues, whereas contractors are more concerned about the possible changes in resource prices (especially after recent high increases caused by COVID-19 and the Russia-Ukraine war). These findings can help owners and potential contractors in intelligent decision-making in the early stages of future highway-construction projects.

Psychological distress in men and women of young adult period during the covid-19 pandemic

Previous studies confirm age and gender as important determinants of crisis adaptation. Therefore, the aim of this study was to examine the pattern of age-gender differences in psychopathological symptoms during the first wave of the COVID-19 pandemic in Croatia. The Brief Symptom Inventory (BSI) was applied in an online survey of a sample of 581 participants. For this purpose, significant differences in the achieved average results between men and women, as well as between the two age groups, were tested. The younger age group consisted of participants of young adult period (18-21 years), while the old group consisted of participants aged 22 to 32 years. The obtained results showed that women experienced symptoms of somatization, sensitivity, depression, anxiety and phobia more often than men. Significant differences were also found in the experience of symptoms of somatization, obsessive compulsiveness, sensitivity, depression, anxiety, hostility, paranoid, and psychoticism between the two age groups. The results indicated that the younger group aged 18-21 years in relation to the older group experienced all these symptoms of psychopathology more often. Furthermore, interaction effects of gender and age were not determined in this study for any of the examined psychopathological symptoms. The results of this study provide insight into some of the examined aspects of mental health during the first wave of the corona crisis in Croatia. Further research into the mechanisms underlying the identified differences in psychopathological symptomatology is certainly needed, especially when it comes to women and young adult group of both genders. © 2021, Opca Bolnica Zadar. All rights reserved.

Use of the risk analysis approach in the serbian army integration process against COVID-19

Current developments have contributed to organisations paying increasing attention to protecting resources, employee safety, and applying quality products and services. There is a need for increasing the application of standards that define the way of managing quality, safety at work, risk, and many others. One such organisation is the Serbian Army, a complex centralised system that requires integrating these standards, and often stricter, in all fields of its activities. The current situation in the world, and therefore in Serbia, is sufficient motivation for the project provided by this paper. This project aims to show the integration of risk management systems and occupational safety systems, through the level of protection and exposure of members of the army to the virus infection COVID-19 during the implementation of emergency tasks, by defining risks and proposing additional measures to reduce the level of risk and increase the protection of military personnel. © 2021 by the authors. It was submitted for possible open access publication under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).