Wyniki wyszukiwania - BazTech

1

Marine traffic, accidents, and underreporting in the Baltic Sea

Sormunen O.-V. E., Hänninen M., Kujala P.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2016

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nr 46 (118)

163--177

EN

This paper presents an overview of ship traffic volume and accidents in the Baltic Sea with a special focus on the Gulf of Finland. The most common accidents are groundings and collisions, usually reported to be caused by human error. The annual number of Baltic Sea accidents reported to HELCOM varied from 34–54 for collisions and 30–60 for groundings. The number of yearly port calls varied from 468–505 thousand with a peak in 2008. Exact port call data could not be found for all ports and hence had to be estimated. The number of line crossingings in HELCOM AIS data was found to be a good, rough surrogate measure for the total number of port calls and could be used if more precise port call data was not available. By analyzing two separate accident databases, an estimate for accident underreporting was calculated. Different statistical methods yielded an underreporting rate in the range of 40–50%. Lastly, the true number of accidents was estimated, based on the estimated underreporting percentage for the Baltic Sea. Based on these results, the true number of true accidents should be first estimated if accident statistics are used in building or validating maritime risk models. When using such models or accidents statistics in decision-making, the underlying uncertainty in the accident statistics should be taken into account as the underreporting frequency estimates are only approximations of the real number of accidents.

2

Real-time winter traffic simulation tool – based on a deterministic model

Lindeberg M., Kujala P., Toivola J., Niemelä H.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2015

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nr 42 (114)

118--124

EN

Increasing maritime traffic, combined with the possible warming of the climate, will affect the demand for icebreaking assistance. Accurately predicting the local demand for assistance without an appropriate simulation tool is hard because of the number of variables that must be considered. This report describes a simulation tool built around a deterministic, ice-breaker movement computer model. The tool is still under development, and has not yet been tested with real data. However, preliminary test results based on selfgenerated input data are promising.

3

Correlation between the Ship Grounding Accident and the Ship Traffic – A Case Study Based on the Statistics of the Gulf of Finland

Mazaheri A., Montewka J., Kujala P.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2013

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Vol. 7, no. 1

119--124

EN

Ship traffic is one of the factors that is presented in almost all of the existing grounding models, and is considered as one of the affecting factors on the likelihood of grounding accident. This effect in grounding accident is mostly accepted by the experts as a common sense or simply by just generalizing the ship‐ship collision cases to grounding accidents. There is no available research on the actual causal link between the ship traffic and grounding accident in the literature. In this paper, authors have utilized the statistical analysis on historical grounding accident data in the Gulf of Finland between the years 1989 and 2010 and the AIS data of the same area in year 2010, as the source of ship traffic data, to investigate the possible existence of any correlation between the ship traffic and the grounding accident. The results show that for the studied area (Gulf of Finland) there is no correlation between the traffic density and the grounding accident. However, the possibility of the existence of minor relation between the traffic distribution and grounding accident is shown by the result. This finding, however, needs further investigation for more clarification.

4

Modelling a ship performance in dynamic ice. Part I, Transforming data into information

Montewka J., Goerlandt F., Kujala P., Haapala J., Lensu M.

Prace Naukowe Politechniki Warszawskiej. Transport

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2013

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z. 95

359--368

EN

For safe and efficient exploitation of ice-covered waters the knowledge about ship performance in ice is crucial. Although ice navigation has received substantial attention over recent decades, there is still no known modelling technique to predict ship’s speed in a dynamic ice field. In order to gain an insight into this process, we need to transform the available data into information first. Only then information can be used to develop new knowledge. This paper demonstrates how to transform still data into dynamic information about operation of maritime transportation system in ice-covered waters. For this purpose, the data from the Automatic Identification System about the performance of a selected ship is used along with a numerical ice forecast model describing the ice field in the analysed sea area.

PL

W celu bezpiecznej oraz wydajnej eksploatacji akwenów pokrytych lodem, wiedza o zachowaniu statku w tych warunkach jest niezbędna. Pomimo, iż żegluga w lodach pozostaje tematem wielu opracowań naukowych, tematyka modelowania zachowania statku w dynamicznym polu lodowym, zwłaszcza w obecności zjawiska kompresji pokrywy lodowej, pozostaje wciąż kwestią otwartą. W artykule omówiono dostępne źródła danych, które po odpowiednim przetworzeniu dostarczą informacji, umożliwiającej lepsze zrozumienie procesu nawigacji statku w dynamicznym polu lodowym co pozwoli na modelowanie tego procesu. W artykule podkreślono zasadność przeprowadzenia procesu przekształcenia danych w informację które następnie można wykorzystać w celu uzyskania nowej wiedzy. Na przykładzie pokazano, iż nawet najdokładniejsze dane, nie dostarczą pełnej informacji, jeżeli nie zostaną odpowiednio przetworzone oraz zinterpretowane, co może prowadzić do błędnych lub niepełnych wniosków.

5

On a risk perspective for maritime domain

Montewka J., Goerlandt F., Kujala P.

Journal of Polish Safety and Reliability Association

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2013

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Vol. 4, No. 1

101--108

EN

In the maritime domain, the risk is evaluated within the framework of Formal Safety Assessment (FSA), introduced by International Maritime Organization in 2002. Although the FSA has become internationally recognized and recommended method, the definition, which is adopted there, to describe the risk, seems to be too narrow to reflect properly the actual content of the FSA. Therefore this article discusses methodological requirements for the risk perspective, which is appropriate for risk management in the maritime domain with the special attention to maritime transportation systems (MTS). This perspective considers risk as a set encompassing the following: the set of plausible scenarios leading to an accident, the likelihoods of the unwanted events within the scenarios and the consequences of the events. These elements are conditional upon the available knowledge about the analyzed system, and understanding of the system behaviour, therefore these two are inherent parts of risk analysis, and need to be included in the risk description.

6

Uncertainty in Analytical Collision Dynamics Model Due to Assumptions in Dynamic Parameters

Stahlberg K., Goerlandt F., Montewka J., Kujala P.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2012

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Vol. 6, no. 1

47--54

EN

The collision dynamics model is a vital part in maritime risk analysis. Different models have been introduced since Minorsky first presented collision dynamics model. Lately, increased computing capac-ity has led to development of more sophisticated models. Although the dynamics of ship collisions have been studied and understanding on the affecting factors is increased, there are many assumptions required to com-plete the analysis. The uncertainty in the dynamic parameters due to assumptions is not often considered. In this paper a case study is conducted to show how input models for dynamic parameters affect the results of collision energy calculations and thus probability of an oil spill. The released deformation energy in collision is estimated by the means of the analytical collision dynamics model Zhang presented in his PhD thesis. The case study concerns the sea area between Helsinki and Tallinn where a crossing of two densely trafficked wa-terways is located. Actual traffic data is utilized to obtain realistic encounter scenarios by means of Monte Carlo simulation. Applicability of the compared assumptions is discussed based on the findings of the case study.

7

Simplified Risk Analysis of Tanker Collisions in the Gulf of Finland

Goerlandt F., Hanninen M., Stahlberg K., Montewka J., Kujala P.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2012

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Vol. 6, no. 3

381--387

EN

Maritime traffic poses various risks in terms of human casualties, environmental pollution or loss of property. In particular, tankers pose a high environmental risk as they carry very large amounts of oil or more modest amounts of possibly highly toxic chemicals. In this paper, a simplified risk assessment meth-odology for spills from tankers is proposed for the Gulf of Finland, for tankers involved in a ship-ship collision. The method is placed in a wider risk assessment methodology, inspired by the Formal Safety Assess-ment (FSA) and determines the risk as a combination of probability of occurrence and severity of the consequences. The collision probability model is based on a time-domain micro simulation of maritime traf-fic, for which the input is obtained through a detailed analysis of data from the Automatic Identification System (AIS). In addition, an accident causation model, coupled to the output of the traffic simulation model is proposed to evaluate the risk reduction effect of the risk control options. Further development of the model is needed, but the modular nature of the model allows for continuous improvement of the modules and the ex-tension of the model to include more hazards or consequences, such that the effect of risk control options can be studied and recommendations made. This paper shows some preliminary results of some risk analysis blocks for tanker collisions in the Gulf of Finland.

8

Estimating the Number of Tanker Collisions in the Gulf of Finland in 2015

Hanninen P., Kujala P., Ylitalo J., Kuronen J.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2012

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Vol. 6, no. 3

367--373

EN

The paper presents a model for estimating the number of ship-ship collisions for future traffic scenarios. The modeling is based on an approach where the number of collisions in an area is estimated as a product of the number collision candidates, i.e. the number of collisions of two ships, if no evasive maneuvers were made, and a causation probability describing the probability of making no evasive maneuvers. However, the number of collisions is presented as a combination of binomially distributed random variables. The model is applied for the assessment of tanker collision frequency in the Gulf of Finland in 2015. 2015 traffic is modeled as three alternative scenarios each having a certain probability of occurrence. The number of collisions can be presented either for each scenario, or as an estimate including the uncertainty in future marine traffic development by taking into account all scenarios and their occurrence probabilities.

9

A Decision Support Tool for VTS Centers to Detect Grounding Candidates

Mazaheri A., Goerlandt F., Kujala P., Montewka J.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2012

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Vol. 6, no. 3

337--343

EN

AIS (Automatic Identification System) data analysis is used to define ship domain for ground-ing scenarios. The domain has been divided into two areas as inner and outer domains. Inner domain has clear border, which is based on ship dynamic characteristics. Violation of inner domain makes the grounding acci-dent unavoidable. Outer domain area is defined with AIS data analyzing. Outer domain shows the situation of own ship in compare with other similar ships that previously were in the same situation. The domain can be used as a decision support tool in VTS (Vessel Traffic Service) centers to detect grounding candidate vessels. In the case study presented in this paper, one type of ship, which is tanker, in a waterway to Sköldvik in the Gulf of Finland is taken into account.

10

A New Definition of a Collision Zone For a Geometrical Model For Ship-Ship Collision Probability Estimation

Montewka J., Goerlandt F., Kujala P.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2011

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Vol. 5, no. 4

497--504

EN

In this paper, a study on a newly developed geometrical model for ship-ship collisions probability estimation is conducted. Most of the models that are used for ship-ship collision consider a collision be-tween two ships a physical contact between them. The model discussed in this paper defines the collision cri-terion in a novel way. A critical distance between two meeting ships at which such meeting situation can be considered a collision is calculated with the use of a ship motion model. This critical distance is named the minimum distance to collision (MDTC). Numerous factors affect the MDTC value: a ship type, an angle of intersection of ships’ courses, a relative bearing between encountering ships and a maneuvering pattern. They are discussed in the paper.

11

A Method for Assessing a Causation Factor for a Geometrical MDTC Model for Ship-Ship Collision Probability Estimation

Montewka J., Goerlandt F., Lammi H., Kujala P.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2011

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Vol. 5, no. 3

365--373

EN

In this paper a comparative method for assessing a causation factor for a geometrical model for ship-ship collision probability estimation is introduced. The results obtained from the model are compared with the results of an analysis of near-collisions based on recorded AIS data and then with the historical data on maritime accidents in the Gulf of Finland. The causation factor is obtained for three different meeting types, for a chosen location and prevailing traffic conditions there.

12

The Effects of Causation Probability on the Ship Collision Statistics in the Gulf of Finland

Hanninen M., Kujala P.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2010

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Vol. 4, no. 1

79--84

EN

In this study the marine traffic safety in the Gulf of Finland is studied by examining the collision probability estimates in a heavily used crossing area. In a commonly applied approach for estimating the probability of collision accidents, so-called number of collision candidates is multiplied with a so-called cau-sation probability. In this study a Bayesian network model for the causation probability estimation is applied with different parameter values in order to examine the effects of weather and human factors on collision probability in the crossing of Helsinki-Tallinn traffic and vessels navigating east- or westbound. The results show that the probability of collisions is very sensitive to the causation probability value and it should be modelled with great care to obtain reliable results.

13

Wybrane problemy modelowania ryzyka w ruchu morskim

Montewka J., Krata P., Kujala P.

Logistyka

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2010

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nr 4

CD-CD

EN

The paper addresses selected problems of marine traffic risk modelling, in respect to collision and grounding probability modelling. Two original models are presented, and a case study regarding ships navigating in selected areas of Gulf of Finland in ice free conditions is putting forward. Probability of vessel colliding is assessed by means of Minimum Distance To Collision (MDTC) based model. The model defines in a novel way the collision zone, using mathematical ship motion model, and recognizes traffic flow as non homogeneous process, unlike other existing models. Calculations presented address waterways crossing between Helsinki and Tallinn, where dense cross traffic during certain hours is observed. Risk profile for a certain period of a day is presented. For probability of grounding a new approach is proposed, which utilizes the gravity model, where spatial interactions between objects in different locations are proportional to their respective importance divided by their distance. A ship at a seaway and navigational obstructions may be perceived as interacting objects and their repulsion may be modelled by a sort of gravity formulation.

PL

W artykule przedstawiono wybrane problemy z zakresu modelowania ryzyka w transporcie morskim, w aspekcie kolizji statków oraz wejść na mieliznę. W pracy przedstawiono dwa nowatorskie podejścia do modelowania prawdopodobieństwa wystapienia powyższych wypadków. Model do oceny prawdopodobieństwa kolizji statków definiuje w nowy sposób strefę kolizji, w oparciu o właściwości manewrowe statku oraz jego hydrodynamikę. Intensywność ruchu morskiego na analizowanym akwenie modelowana jest w oparciu o proces niestacjonarny, w przeciwieństwie do istniejących modeli. Model oceny prawdopodobieństwa wejścia na mieliznę wykorzystuje model grawitacyjny, gdzie statek i otaczające go płycizny traktowane są jako masy, wzajemnie na siebie oddziaływujące. Model określa bezpieczny obszar manewrowy dla danego statku i danego akwenu. Analiza ryzyka przeprowadzona została dla dwóch wybranych akwenów w Zatoce Fińskiej. Jako konsekwencje wypadku przyjęto model kosztów, konstruowany w oparciu o dane statystyczne z międzynarodowego fundusz IOPCF, który pokrywa koszty w związku z rozlewem olejowym na morzu.

14

A model for risk analysis of oil tankers

Montewka J., Krata P., Goerlandt F., Kujala P.

Archives of Transport

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2010

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Vol. 22, iss. 4

423-445

EN

The paper presents a model for risk analysis regarding marine traffic, with the emphasis on two types of the most common marine accidents which are: collision and grounding. The focus is on oil tankers as these pose the highest environmental risk. A case study in selected areas of Gulf of Finland in ice free conditions is presented. The model utilizes a well-founded formula for risk calculation, which combines the probability of an unwanted event with its consequences. Thus the model is regarded a block type model, consisting of blocks for the probability of collision and grounding estimation respectively as well as blocks for consequences of an accident modelling. Probability of vessbl colliding is assessed by means of a Minimum Distance To Collision (MDTC) based model. The model defines in anovel way the collision zone, using mathematical ship motion model and recognizes traffic flow as a non homogeneous process. The presented calculations address waterways crossing between Helsinki and Tallinn, where dense cross traffic during certain hours is observed. For assessment of, a grounding probability, a new approach is proposed, which utilizes a newly developed model, where spatial interactions between objects in different locations are recognized. A, ship at a seaway and navigational obstructions may be perceived as interacting objects and their repulsion may be modelled by a sort of deterministic formulation. Risk due to tankers running aground addresses an approach fairway to an oil terminal in Skoldvik, near Helsinki. [...]

PL

W artykule przedstawiono model oceny ryzyka w transporcie morskim, w aspekcie kolizji statków oraz wejść na mieliznę. W modelu przyjęto jeden typ statków, tankowce do przewozu ropy naftowej, z uwagi na fakt, iż w przypadku wystąpienia kolizji lub kontaktu z dnem statek ten może stanowić bardzo poważne zagrożenie dla środowiska. W pracy przedstawiono dwa nowatorskie podejścia do modelowania prawdopodobieństwa wystąpienia powyższych wypadków. Model do oceny prawdopodobieństwa kolizji statków definiuje w nowy sposób strefę kolizji, w oparciu o właściwości manewrowe statku oraz jego hydrodynamikę. Intensywność ruchu morskiego na analizowanym akwenie modelowana jest w oparciu o proces niestacjonarny, w przeciwieństwie do istniejących modeli. Model oceny prawdopodobieństwa wejścia na mieliznę wykorzystuje model grawitacyjny, który wyznacza bezpieczny obszar manewrowy dla danego statku i danego akwenu. W modelu tym statek i otaczające go płycizny traktowane są jako masy, wzajemnie na siebie oddziaływujące. Obydwa modele wykorzystują dane o ruchu statków zarejestrowane w systemie automatycznej identyfikacji statków (AIS). Analiza ryzyka przeprowadzona została dla dwóch wybranych akwenów w Zatoce Fińskiej. Jako konsekwencje wypadku przyjęto model kosztów, skonstruowany w oparciu o dane statystyczne z międzynarodowego funduszu IOPCF, który pokrywa koszty w związku z rozlewem olejowym na morzu.

15

The quantitative assessment of marine traffic safety in the Gulf of Finland, on the basis of AIS data

Montewka J., Kujala P., Ylitalo J.

Zeszyty Naukowe / Akademia Morska w Szczecinie

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2009

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nr 18 (90)

105-115

EN

Navigational risk assessment is a complex process, which aims to determine the level of safety over the analyzed area. Usually two approaches are used: qualitative and quantitative. Engineers tend to view risk in an objective way in relation to safety, and as such use the concept of risk as an objective safety criteria. Among engineers risk is defined as a product of probability of occurrence of an undesired event and the expected consequences in terms of human, economic and environmental loss. These two components are equally important; therefore appropriate estimation of these values is a matter of great significance. This paper deals with one of these two components: the probability of vessels. collision assessment. A new approach for probability estimation of collision between vessels is presented, rooted in aviation experiences. The presented model for collision frequency estimation takes into account historical traffic data from AIS, generalized vessel dynamics and uses advanced statistical and optimization methods (Monte-Carlo, Genetic Algorithms).

PL

Szacowanie ryzyka nawigacyjnego jest złożonym procesem, którego celem jest określenie poziomu bezpieczeństwa na analizowanym akwenie. Zazwyczaj stosowane są dwa podejścia: jakościowe i ilościowe. Inżynierowie definiują ryzyko jako prawdopodobieństwo wystąpienia niepożądanego zdarzenia oraz wynikających z niego konsekwencji tj. utraty życia ludzkiego, aspektów ekonomicznych oraz zanieczyszczenia środowiska. Te dwa komponenty są w równym stopniu ważne; dlatego odpowiednie oszacowanie wartości ma bardzo duże znaczenie. W artykule zaprezentowano jeden z dwóch czynników: prawdopodobieństwo szacowania kolizji statków. Przedstawiono nowe podejście dotyczące szacowania prawdopodobieństwa kolizji pomiędzy dwoma statkami, które zostało zaczerpnięte z doświadczeń lotnictwa. Opisany model szacowania częstotliwości kolizji bierze pod uwagę dane otrzymane z systemu AIS, uogólnioną charakterystykę dynamiki statku przy użyciu zaawansowanych metod statystycznych i optymalizacyjnych (Monte-Carlo, algorytmy genetyczne).

16

Fracture toughness of laser stake welds in shipbuilding industry

Socha G., Kujala P.

Engineering Transactions

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2000

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Vol. 48, iss. 2

135-151

EN

A new technology of stake welding with the use of high power lasers was developed in the framework of EU research program "Advanced Welding for Closed Structures". This technology enable welding from outside of closed profiles due to high penetration of laser beam into the material. More than 650 static, fracture toughness and fatigue tests were performed during the research program to investigate strength of such welds. In this paper, investigations of static strength and fracture toughness are presented, results of fatigue testing will be reported elsewhere. As the result of the tensile and bend tests, very good strength and ductility of fusion zone (FZ) and heat-affected zone (HAZ) were found. Also the fracture toughness in lowered temperature was found to be satisfactory. Both traditional impact (Charpy) test and modern methods of measuring the crack tip opening displacement (CTOD) were utilised, and their results in the form of tearing energy per unit surface were compared. Also fatigue crack growth rate (FCGR) tests were performed at the constant DK value, the crack was propagating in the direction transversal to the weld midline. This technique allowed the observation of FCGR variations in different zones of the welded joint.