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Browsing by Keyword collision avoidance:

  • Śmierzchalski, Roman; Kuczkowski, Łukasz; Kolendo, Piotr; Jaworski, Bartosz (Scientific Journals of the Maritime University of Szczecin, Zeszyty Naukowe Akademii Morskiej w Szczecinie, 2012)
    This paper presents the use of mean crossover genetic operator for path planning using evolutionary algorithm for collision avoidance on sea. Mean crossover ensures widening of the possible solutions’ set that can be achieved in comparison to exchange crossover variant. The research shown, that the mean crossover allows to achieve results independent from the initial generation and quicker transition of the algorithm from the exploration to the exploitation phase. New version of the algorithm allows for an effective solution search for the problem of a collision scenario on sea
  • Mou, Jun-min; Tang, Guang-hui; Yue, Hao Rong and Xuan; Rong, Hao (Scientific Journals of the Maritime University of Szczecin, Zeszyty Naukowe Akademii Morskiej w Szczecinie, 2013)
    The ridge regression is presented for identify manoeuvring indices in Nomoto’s model, and the result indicates that the method is robust and does not rely on initial estimation. For selecting appropriate AIS data for manoeuvring indices predicting, a frequency domain identification method is presented.
  • Praczyk, Tomasz (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    Autonomous underwater vehicles are vehicles that are entirely or partly independent of human decisions. In order to obtain operational independence, the vehicles have to be equipped with specialized software. The task of the software is to move the vehicle along a trajectory while avoiding collisions. In its role of avoiding obstacles, the vehicle may sometimes encounter situations in which it is very difficult to determine what the next movement should be from an ad hoc perspective. When such a situation occurs, a planning component of the vehicle software should be run with the task of charting a safe trajectory between nearby obstacles. This paper presents a new path planning algorithm for a Biomimetic Autonomous Underwater Vehicle. The main distinguishing feature of the algorithm is its high speed compared with such classic planning algorithms as A*. In addition to presenting the algorithm, this paper also summarizes preliminary experiments intended to assess the effectiveness of the proposed algorithm.
  • Wójcik, Anna; Banaś, Paweł (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    One of the factors affecting a ship’s safety during its voyage is the ability to detect encounter situations. Navigators mostly use two parameters: closest point of approach (CPA) and time to CPA (TCPA). Their limit values, considered as safe, depend on the parameters of the vessel, geographic area, and weather conditions. These limits are set by the navigator and are based on his experience; however, in specific situations, there is a need to use other parameters, such as ship domain. It is very important for the automated communication system to determine the critical moment when intership communication should be started. The article presents an algorithm of automatic detection of situations where the communication should be initiated. The influence of data relating to the vessel, geographic area, and weather conditions can be taken into account. The output produced by the program, based on the authors’ algorithm, is presented.
  • Baldauf, Michael; Mehdi, Raza; Fischer, Sandro; Gluch, Michael (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    Avoidance of collisions is one of the most important tasks for the officer of the watch on a ship’s bridge. Measures and actions required to avoid such accidents are described in the Convention on the International Regulations for Preventing Collisions at Sea (COLREGs) adopted by the International Maritime Organization (IMO) in 1972 and still valid, with several minor amendments, since then. On the basis of a proper look-out at all times, by sight and hearing, and the use of all available means, also including technical equipment installed on-board as well as information provided by a Vessel Traffic Service (VTS), the navigating officer collects traffic and environmental data and combines them with their own ship data to construct a mental traffic image for the assessment of risk of collision with other objects in the vicinity. In the case wherre there is an unacceptable risk she or he has to decide on taking action. In most of the cases decision making is appropriate to the prevailing circumstances and ships maneuver and pass at a safe distance. Only in very rare cases, due to whatever reasons, watch officers fail in taking appropriate actions in good time. It is assumed that, if effective alerting algorithms would be available, a substantial number of collisions at sea, and especially in coastal waters, can be avoided by making the watch officer aware that the ‘last line of defence’ for taking action is close to come. It is assumed that there is potential in applying the principle of the resolution advisory alert of an ACAS (Airborne Collision Avoidance System)/TCAS (Traffic Alert and Collision Avoidance System) in aviation and adapt it to the needs of maritime traffic. In this paper, the authors introduce a method for triggering collision warnings by focusing specifically on the critical last phase of an encounter and taking into account the maneuvering characteristics of the navigating ship. They comprehensively explore the application using scenario studies discussing the operational aspects of varying implementation states (one ship only, SOLAS ships only).
  • Pietrzykowski, Zbigniew; Magaj, Janusz; Wielgosz, Mirosław (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    Port approaches are high-traffic areas with limited manoeuvring space. Navigation in such areas requires the analysis of large amounts of information, which can impede decision processes. One solution may be the development of decision support systems dedicated to these areas. This paper presents an attempt to build a navigation decision support system operable in the approach area leading to the port of Świnoujście (Poland), with ship domain implemented as a safety criterion. Assumptions for a decision support system to be used by sea-going vessels in port approach areas are formulated and discussed. Specific features of these areas, such as traffic density, bathymetry, available manoeuvring space and legal limitations are taken into account. The source and scope of information available to the ship have been analysed. The scope of decision support has been defined. A ship domain has been proposed as a safety criterion. Approach areas leading to the port of Świnoujście have been investigated on the basis of real Automatic Identification System (AIS) data. Vessel movement processes in the chosen area were analysed. Ship domains in various parts of the area were determined. The first results concerning criteria for navigational safety assessment are presented. The conducted studies showed significant differences in the size of domains. A case study was performed on a decision support system operable in the approach area leading to Świnoujście.

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