The article discusses the problem of damage to the traction cables of medium and low voltage systems for DC tram traction power devices. It presents types and mechanisms of damage to various types of cables and compares a number of failures. Some chosen particularly interesting cases have been discussed.

In this study, the parameters have been developed, characterized by the invisibility level of the message, which is embedded in a text environment, and methods which determine the values of these parameters. Also a review of the system composition of steganography, which is oriented to the use of text digital environments. Also included is the concept of semantic vocabulary of digital environments and text messages. Were also made analysis methods for implementing messages, depending on the fit of these dictionaries

There are two aspects of position coordinates accuracy in navigation: global accuracy and local accuracy – relative to navigational dangers. The latter case refers to the assessment of position (distance) accuracy in respect to the nearest navigational danger, a hazard to navigation. The directional error is a relevant measure for such assessment. The directional error curve is analyzed in this article as a particular case of the Booth elliptical lemniscate. The curve graph illustrates the confidence interval of point position errors in a given direction (about 68%).

The article discusses an algorithm devised for presentations of acceptable solutions to collision situations of ships at sea. The solutions, course alteration ranges, are determined in compliance with the Collision Regulations. The solutions account for cases where more than two vessels are involved in a collision situation. The algorithm has been implemented into NAVDEC, a navigational decision support system. The presented results have been obtained in field research, onboard the motor vessel Nawigator XXI.

The article uses the analytical equation for the work function of metals, made by one of the authors, to study the structure of aluminum alloys, which are increasingly used in the shipbuilding industry. For example, of selected alloys Al-Cu, Al-Ta and Al-Ti are presented graphically changes in work function depending on the percentage composition of the alloy. Also presented an equation that allows to evaluate the work function for multicomponent alloys.

Construction of new ports requires applying the entire range of methods and the close cooperation between designers and specialists of different field including safety of navigation or oceanography. At present there is no possible to conduct of such investments without carrying out simulation examinations. These studies most often take place as multistage where the next stage is the result of the previous one. The paper presents complex method of water areas optimization with consideration of navigational safety. In the present study was implemented real-time simulation method. Methods of the simulation of the real time leaning against manoeuvre simulators have been applied. Two distinct from each other alternatives have been explored and the best in terms of safety of navigation has been selected as final. The results were used as a guideline for the development project of a small Polish seaport in Mielno.

The system of sea waterways, as defined in this article, consists of three subsystems: waterways, navigational, and traffic control. This author has defined a state vector for conditions of safe operation of ships on a waterway and described interrelations between parameters of sea waterway system and the state vector of safe ship operation conditions.

In this work are described and researched methods of protection of navigation system from unauthorized attempts to substitute trajectory of moving objects, guided by radio or satellite. The proposed methodology to detect such interference in the operation of the navigation system is based on the use of data for historical, located on the premises trajectory.

This article presents equipment which monitors vehicles in sea ports and furthermore management of transshipment. A method and results of an integrated vehicle detector was presented. The studied unit represents the newest trend in building detectors, where one device applies a couple of detection methods. The studied device applied: passive infrared (PIR), ultrasonic and electromagnetic microwave radiation. The aim of the research was to describe how accurate the vehicle detector TT 298 acquires data. The evaluation pertained to: counting vehicles, describing structures according to the type, vehicle speed measurement.

Presenting a model of radiocommunication events management system, we have described its structure and flow of input and output data streams. Besides, we have pointed out the need for developing a system of radiocommunication events management, and possible applications of the developed model.

This author presents models of processes taking place at a waterway intersection. The measures of traffic processes under consideration are the number of vessels waiting to enter an intersection and delay time of these vessels. The applicability of specific models is discussed along with their usefulness as a function if input intensity of vessel stream flowing into a waterway intersection.

The main aim of this paper is to introduce the possibility for applying rough sets theory to analyze the test result which candidates for special operator (ATC controller) must took while their recruitment. Recruitment after reaching the person being trained, consisting of two parts (theoretical and practical) and lasting more than two years. The candidate must be distinguished features such as an excellent orientation in space, perception, logical thinking, divided attention, stress resistance, ability to plan, very good health and a very good knowledge of Polish and English. Paper consists a detailed description of the recruitment for special operator – ATC controller position and brief introduction to the rough sets theory including basic concepts and methodology. The analytical part of this paper describing set of psychophysical characteristics of operator, means by which and based on actual data, decision table is created. Afterwards all data are analyzed in the special computer software. The paper ends with a summary, the results of the analysis are discussed.

The paper contains a proposal of developing new data structures, which would describe a digital terrain model (DTM). The essential characteristic of of the proposed design is the fact, that they consist of multiple layers, where each layer describes the same, but with different accuracy (density point), and the whole structure describes a selected seabed area. Using such a novel data structure will allow for creating seabed models incorporating data of varying accuracy, and the particular layers might be used for specific purposes (e.g. low density data for quick visualisation, medium density data for general calculations, high density data for analysis small objects on the seabed). The author describes the assumptions underlying the development of such a structure, its functionality, possible applications and properties, as well as the outline of planned research regarding the structure.

The paper presents results of research concerning meteorological and hydrological conditions in the storm related with the Xaver cyclone moving fast over the Baltic Sea. The analyses were based on remote sensing data from radars in Świdwin and Gdańsk Rębiechowo and hydrometeorological data from direct measurements conducted at the coastal stations of the Polish Navy, marine stations of the Institute of Meteorology and Water Management, hydrometeorological station on the “Baltic Beta” oil rig and the Coastal Research Station of the Institute of Hydroengineering of the Polish Academy of Sciences in Lubiatowo. The assessment of the synoptic situation was made using surface weather charts, satellite images of cloud cover and meteorological radars products. The measurement data were used to analyze the surface and upper air wind fields for assessment of the hydrological situation (water condition, height and direction of the significant and maximum waves) and evaluation of threats to sea navigation and coastal infrastructure.

To forecast the optimum route passage of a vessel in the real weather conditions using the so-called velocity characteristics of the ship. These are developed in the way, as to have a very simple form, which can not guarantee high precision in calculating the speed of the vessel. The paper presents a mathematical model of the external forces operating in the vessel and the algorithm to solve this model for calculating the instantaneous speed of the vessel in the selected weather conditions. Made of a computer program, after appropriate research and testing, can be used to optimize the transport route of the ship.

Modern marine Diesel prime movers are equipped with so called ‘common rail’ as a part installed in the fuel injection system. This kind of design, gives a possibility to control fuel injection process in ways which were not available to carry out on conventionally designed engines. During the ship operation with a reduced speed and reduced load of the main engine, especially under the “Super Slow Steaming” conditions the waste heat recovery process in exhaust gas boiler is being disturbed. In the article, there is presented a possibility to increase the steam production of the waste heat boiler by interference in the fuel injection pattern for the engine. For the selected system “low speed main engine – smoke tube exhaust gas boiler” the test session has been carried out under the real ambient and operational condition of the ship to verify described possibility. Obtained results have been presented.

The paper presents an analysis of a rapid atmospheric process which in the beginning of December of 2013 moved over Europe from NNW in the form of a deep cyclone. The analysis aim is to verify the Weather Research & Forecasting Model results of daily numerical weather forecasts of extremely dynamic atmospheric processes. The applied spatial resolution of the computational grid of 36.3 km does not reveal the sub-grid processes. In case of the Xaver cyclone development and movement, the spatial step may be of significant importance. It is planned to analyze the case using data computed at better resolutions

Reference system was adapted EVRS (European Vertical Reference System), which is based on the level of NAP (Normal Amsterdam Peil) for the spatial imaging extreme levels of the Baltic Sea. The observational data on sea levels have been converted of the selected 38 stations in each of the Baltic countries to the level of NAP (Normal Amsterdam Peil). The images of the Baltic Sea area were obtained in a uniform reference system, for the example of chosen stormy situation of 1–2 November 2006, and the spatial distribution of the maximum and no maximum sea levels that occurred during the 1960–2010 year.

The paper presents an overview of methods for detecting the spoofing of GNSS open service code signals illustrated with the example of C/A GPS signals. GNSS signal spoofing is an attack method where a signal is transmitted that appears authentic but it induces the receiver under attack to compute an erroneous navigation solution, time, or both. Usage of commercially available satellite compasses and two antennas systems for the detection of such threat is described in detail.

During preliminary stages of ship design, decisions on ship properties are made only with little knowledge on ship hull geometry – a ship designer has only the basis dimensions at his disposal. Therefore on these initial stages of ship design, methods of calculation of ship properties (eg. resistance) on the basis of basic design criteria are indispensable. The article presents a new method of calculation of bulk carriers resistance which proves exact even with a minimum number of geometrical parameters of a ships hull.

While a ship is sailing, wind is acting upon the ship hull above water. As a result, additional resistance, as well as transfer drift force and drift moment emerge. The article presents an approximate method of calculating these forces for bulk carriers, in the form useful at preliminary ship design, when only basis ship dimensions are known.