How is the implementation of public transport services perceived by the public in the context of the sharing economy? What social and economic elements determine their development? The task of this article is to look for answers to questions formulated in this way. A quantitative method was used to conduct the research; the technique that was used was the CASI online survey. Profitability calculations were carried out and compared for three variants of vehicle use: rented, new and used. The deadlines for exceeding the profitability thresholds were set under the assumed preconditions for the analyzed variants. The results that were obtained provided an assessment of the customers’ opinions on the use of elements of the sharing economy in public passenger transport, and enabled the formulation of determinants of the popularization of these solutions as well as a determination of the cost-effectiveness thresholds for practical applications.

The proper selection of statistical distributions is important for modeling port operations using simulations or queuing theory. The aim of this study was to determine the appropriate statistical distributions for modeling random processes related to ship operations in ports, including ship arrivals, berthing maneuver processes, service processes, and unberthing maneuver processes. A literature review was performed on the statistical distributions used in these random processes. In addition, the port data on ship operations gathered from three different ports in Turkey were examined. Goodness of fit tests were conducted to determine the appropriate distribution for each process.

Task planning involves automating the creation of the routes for vessels with known coordinates in a confined space. The management of vessel release in a given area affects the time required for a vessel to complete its voyage, and maximizing vessel performance involves identifying the shortest route. A key issue in automating the generation of the optimal (shortest) routes is selecting the appropriate mathematical apparatus. This paper considers an optimization method based on a recursive algorithm using Bellman-Ford routing tasks for large dimensions. Unlike other optimization techniques, the proposed method enables the shortest path to be assessed in a network model with a complex topology, even if there are arcs with negative weights. The practical implementation of the modified Floyd algorithm was demonstrated using a sample automated build and using it to calculate a network model with a complex topology, using an iterative procedure for a program prepared in MATLAB. Implementation of the computer model is simple, and unlike existing models, it eliminates restrictions associated with the presence of negative weights and cycles on a network and automates search shortcuts in ground branch functional means in MATLAB. To confirm the accuracy of the obtained results, we performed an example calculation using the network. The proposed algorithm and recursive procedure are recommended for finding energy-efficient solutions during the management of mobile objects on waterways.

In this article, a systematic solution for mitigating the DFG (Derelict Fishing Gear) problem has been presented using an example of a DFG wreck operation. The planning process has been described in detail and the influence of ghost net recovery on the marine environment has been shown. The research was performed on selected wrecks found in the Polish economic zone and the method consisted of scanning the sea bottom using 2D sonar. Based on the information obtained by the sonar, the ghost nets were later retrieved using a creeper (in cases where the ghost nets were lying on the sea bottom) or with the help of divers (in cases where the nets were sitting on the wrecks). The results have shown that, taking into consideration the research area of the Baltic Sea, the presented method will be satisfactory in most cases.

Gas carriers are one of the most advanced types of ships and are equipped with the latest technological achievements. Due to the development of this industry, the demand for ethylene transport by sea has increased significantly in recent years. Nonetheless, it is one of the most problematic loads in terms of loading operations. Due to the small density differences between ethylene and nitrogen, ethylene is one of the most problematic hydrocarbons with respect to the efficient gasification of cargo tanks. Additionally, ethylene is one of the most expensive cargoes carried on gas carriers. The above aspects make it necessary to carry out a detailed analysis of the flushing of nitrogen-loaded cargo tanks with ethylene vapors to determine the range of technical parameters to enable more efficient tank gassing-up. This paper provides a detailed analysis of an experimental cargo tank gassing-up operation on an ethylene carrier. The process was carried out in accordance with previously-determined assumptions to optimize the discussed operations, assess how the cargo tank pressure influences this process, reduce cargo loss during gassing-up, and eliminate cargo loss during its cooling. The conclusions from this experiment provide guidelines for subsequent tests.

This paper presents an approach to rationalize the energy consumption of road transport towards sustainability in a steady-state economy. The research hypothesis is that the rationalization of the energy consumption of road transport is affected by drift and shocks, which desynchronizes the adjustment mechanism from equilibrium. The objective of this research was to incorporate the model of energy consumption of road freight transport with the goals of sustainability by considering ecological and constructivist rational orders, the issue of order drift, and the occurrence of shocks. The research investigated Poland from the first quarter of 2004 to the fourth quarter of 2018. A model for rationalizing the energy consumption of road transport was constructed using the vector error correction model and cointegration techniques. The model revealed one cointegrating relationship and showed statistically significant unlimited drift. The level of changes to long-term equilibrium appeared respectively for GDP – 1.8%, PPI for energy – 7.3%, and for energy consumption – 10.9%. We observed a weak sustainability between the energy consumption of road transport and GDP and a strong sustainability between energy consumption of road transport and PPI energy. It was determined that price shocks had a positive impact (at the estimated point level around 0.06) and supply and demand shocks had a negative impact (at the level estimated point around –3).

Each year, global navigation satellite systems (GNSS) improve their accuracy, availability, continuity, integrity, and reliability. Due to these continual improvements, the systems are increasingly used in various modes of transport, including rail transport, the subject of this publication. GNSS are used for rail passenger information, rail traffic management, and rail traffic control. These applications differ in the positioning requirements that satellite navigation systems must meet. This article presents the methods and systems of rolling stock location and tracking using the Polish State Railways (PKP) as an example. The information on the equipment used for train positioning is not specified anywhere, hence they may differ, even for the same multiple units travelling in different parts of the country. In addition, the publication presents the progress of the European Train Control System (ETCS) implementation by the PKP.

The offshore oil & gas industry is one of the most important industries in the world and has a direct impact, either positive or negative, on the global economy. In order to ensure continuous exploration and production, various offshore installations must be supplied with all the necessary materials and cargo on a regular daily basis. The most convenient way to do this is by using different types of offshore supply vessels, which constitute one of the most expensive factors in the logistics supply chain in the offshore oil and gas industry. Reliable, cost-efficient, environmentally friendly transport and technically “fit for purpose” offshore vessels are the goal of any oil & gas company. This article presents a review of the offshore oil & gas market and the business strategy which includes offshore supply vessels. The research includes SWOT analyses to emphasize the advantages and challenges in the oil & gas industry and presents the correlation between the crude oil price and the daily rate of offshore vessels and aims to predict future movements in the market.

This study used a spatial distribution analysis to identify the risky areas in the Çanakkale Strait – one of the narrowest waterways with high marine traffic – in terms of ship accidents. To accomplish this, a point density analysis, as part of the geographic information systems (GIS) methodology, was used to create accident density distributions and thematic maps. A total of 162 marine accidents in the Çanakkale Strait between 2007 and 2018 were taken into account. Detailed technical data of accidents were obtained from accident reports provided by the Turkish Maritime Search and Rescue Coordination Center (TMSRCC). The results showed that, among the 162 cases, bulk carriers have the highest accident rate, and most accidents at the Nara Turn were caused by engine failure. In addition, accidents due to navigational failure occurred in every region of the strait. Remarkably, factors directly and indirectly related to human error were still the determining factors in marine accidents. As a result, the risk of marine accidents was higher in the narrow portions of the waterway, and navigation was difficult, especially in areas such as the Nara Turn Point. In future research, it is recommended to consider a wider period of activities using different methods to provide more comprehensive results.

Dear Readers, I am pleased to present to you No. 62(134) of the Scientific Journals of the Maritime University of Szczecin. This issue presents the results of nineteen research papers in six thematic groups: Civil Engineering and Transport, Environmental Engineering, Mining and Energy, Information and Communication Technology, Management and Quality Science, Mechanical Engineering, and Miscellaneous. The first thematic group – Civil Engineering and Transport – contains five papers. In the first, the authors analyse the causes of 162 accidents of marine vessels in the Strait of Çanakkale. The second paper provides a SWOT analysis of the various vessels used in offshore crude oil and gas extraction. The next paper in this section addresses methods for locating and tracking rolling stock using global navigation satellite systems (GNSS) using Polish State Railways (PKP) as an example. The fourth article presents a model for improving the energy efficiency of road transport based on the sustainable development of the national economy. The last publication presents a detailed experimental analysis of loading gas into cargo tanks on ethylene carriers. The second group – Environmental Engineering, Mining and Energy – contains one article. The author presents safe and environmentally friendly techniques for the recovery of derelict fishing gear (DFG). The next group – Information and Communication Technology – also contains one article. In this publication, the authors present a MATLAB algorithm to identify energy-efficient solutions for managing movable facilities on waterways. There are two articles in the fourth group Management and Quality Science. The authors of the first paper present the statistical distributions of operational surveys performed by different marine vessels in a port. The second paper investigates the profitability of operating three types of vehicles: rented, new, and used. Seven articles are included in the fifth thematic group, Mechanical Engineering. The papers include various studies primarily related to numerical methods, in particular, the finite element method (FEM) and the finite volume method (FVM). This group also includes a publication on safety management issues, with a focus on the impact of safety culture standards on reducing accidents in a ship engine room. In the last group – Miscellaneous – there are three articles with very different subjects. The first paper describes how to optimize and ensure the reliable operation of a port oil terminal to maximize the lifetime of its critical infrastructure. Another paper addresses the planning and control of rescuing a person overboard based on the SAR Navi-Harbor module for the Baltic Sea. The last article reports the impact of regional development funds (RDFs) on the regional growth of small and medium-sized enterprises and the impact of intellectual property on the economic development of the studied country. I take this opportunity to encourage authors from around the world to publish their findings in the Scientific Journals of the Maritime University of Szczecin. All readers are invited to visit our website: http://scientific-journals.eu/ which provides readers with access to electronic versions of current and older issues.

Dear Readers, It is my great pleasure to present to our readers the most recent issue 61 (133) of the Scientific Journals of the Maritime University in Szczecin. This time, the Scientific Journals contains the results of nineteen research endeavors that are categorized into seven thematic groups: Automation, Electronic and Electrical Engineering, Civil Engineering and Transport, Environmental Engineering, Mining and Energy, Information and Communication Technology, Management and Quality Studies, Mechanical Engineering, and Miscellaneous. The first section – Automation, Electronic and Electrical Engineering – contains three papers. The authors of the first paper discuss issues with compensating harmonic currents, reactive power, and imbalances in the bypass load power of a closed-loop control of a shunt active power filter. The next paper describes a method for steering the mechatronics of a shaft generator by applying permanent magnet synchronous generators (PMSG), allowing for work stability while changing the rotational speed of the shaft. In the third paper, the authors present their research on the durability of selected LED lamps. The second section – Civil Engineering and Transport – includes five papers. The first describes the application of a parametric method in railway transport, especially for track infrastructure inventory. The authors of the second paper share their interesting results regarding simulations of accident results and navigational risks in fairways stemming from a ship’s technical malfunctions. The problems discussed in the third paper involve determining the position of inland vessels in the immediate vicinity of the Długi and the Kolejowy Bridges in Szczecin. As for the fourth paper, the author analyses issues associated with the safe management of a ship’s exploitation, especially as it relates to maritime safety culture. The last article in this section examines social expectations regarding public transport using the example of Szczecin. The third section – Environmental Engineering, Mining, and Energy – contains one paper that reports simulated oil spills and their spread under various atmospheric conditions. The fourth section – Information and Communication Technology – also includes one article, which presents a software pack for monitoring various possible events that threaten a ship and its crew. The fifth section – Management and Quality Studies – contains three papers. The first is devoted to human resource management in a company with regard to its development. The subject matter of the next two papers is related to the social responsibility of managing maritime ports and the environmental and societal effects of such management. The penultimate section – Mechanical Engineering – contains three articles. The authors of the first paper discuss torsional, longitudinal, and lateral vibrations of a propeller shaft. The next paper presents changes in the microstructure of elements made of unalloyed cast steel with 0.3% carbon content regenerated using welding technology. The third paper presents a method for gassing-up ethylene without uncontrolled losses and disruptions in a transshipment installation. 6 Scientific Journals of the Maritime University of Szczecin 61 (133) The last section – Miscellaneous – contains three articles. The author of the first one describes a model of safe infrastructure for an oil terminal with regards to its exploitation process. The next paper discusses the effects of LED lighting on human health, especially the eyes. The last paper contains a comparative bibliometric analysis of sources of maritime transport based on the Web of Science database. I invite all readers to visit our website: http://scientific-journals. eu/. It provides all essential information on the publication process, along with full papers included in the current 61 (133) issue and archival papers published in the Scientific Journals of MUS.

This paper presents the compensation tasks performed by a shunt active power filter, including compensation of harmonic currents, reactive power, and an unbalanced load current. The paper demonstrates novel control of the shunt active power filter in a closed-loop system. The control algorithm was verified by performing simulations and compared the simulated results with those obtained in an open-loop control system. All simulations were conducted in the PLECS program using a control algorithm written in C programming language.

Among the various methods for generating electricity on a ship, a shaft generator system is characterized by the highest energy and economic efficiency. The use of a Permanent Magnet Synchronous Generator (PMSG) in these systems, in comparison to classic synchronous generators, improves the ship’s propulsion efficiency and the system’s reliability. The problem of adjusting the PMSG’s excitation and changing the speed of the generator’s shaft can be solved by the use of modern power and electronic systems. This article presents a method for controlling the mechatronic system of a shaft generator with a PMSG, which enables stable operation to be achieved when changing the rotational speed of the shaft. Analytical and simulation studies were carried out and have enabled the boundaries of the area in which the PMSG can operate to be determined, while maintaining the required electrical power. The results have shown that the use of a PMSG instead of an EESG can increase the energy efficiency of the shaft generator system and increases the system’s reliability.

Luminous flux reduction during operation affects the operating lifetimes of LED lamps. Due to the very long lifetimes of LED sources, i.e. tens of thousands of hours, the lifetime declared by the manufacturer is most often determined by forecasting the luminous flux reduction. Lifetime forecasting is performed based on measuring the operating luminous flux reduction within a time frame of at least 6000 hours, every 1000 hours, followed by extrapolating the obtained results with a relevant exponential curve. This article presents the results of measurements of luminous flux changes taking place between 0 and 10,000 operating hours of several LED light sources. The obtained results were analyzed, and the lifetimes of the examined lamps were evaluated.

For many years, satellite systems have seen widespread use in a variety of technical applications, as well as in operations related to setting-out and the exploitation of track infrastructure. Their main applications include an inventory of the trackage course and detecting changes in its position. In both of these tasks, the most important element that determines the quality of an analyses is the high accuracy of the determinations being carried out. Satellite surveying techniques are not always sufficiently accurate, and in such cases, it is necessary to employ other land surveying methods to process surveying data. This article presents the authors’ considerations with regards to the possibility of applying one of the most common land surveying adjustment methods, the parametric method, to operations related to an inventory of tram infrastructure in Gdańsk. The results are based on surveys carried out during a surveying campaign in the autumn of 2018. The considerations presented in the article concern a small part of the research conducted under project No. POIR.04.01.01-00-0017/17 entitled “Development of an innovative method for determining the precise trajectory of a railborne vehicle” which is being implemented by a consortium of Gdansk University of Technology and Gdynia Maritime University.