Probabilistic Selection of Ship-Ship Collision Scenarios

2013 ◽  
Author(s):  
Samy A. M. Youssef ◽  
Jeom K. Paik ◽  
Yang Seop Kim ◽  
Min Soo Kim ◽  
Fai Cheng
Keyword(s):  
Sampling Technique ◽  
Random Variable ◽  
Quantitative Risk Assessment ◽  
Design Stage ◽  
Density Distributions ◽  
Design Loads ◽  
Ship Collision ◽  
Accident Scenarios ◽  
Probability Density Distributions ◽  
Double Hull

Within the framework of quantitative risk assessment and management in the design stage, it is essential to select relevant sets of accidental scenarios, while a huge number of possible scenarios are obvious. The current industry practices are likely based on prescriptive approaches for the most unfavorable accidental scenarios. However, these approaches are often inadequate for obvious reasons because they may result in too large values of design loads in some cases but they may underestimate design loads in other cases. In the present study, an innovative method using probabilistic approaches is suggested to select relevant sets of ship-ship collision accident scenarios which represent all possible ones. Historical database for each of individual collision parameters which is dealt with as a random variable have been collated and are analyzed by statistical methods to characterize the probability density distributions. A sampling technique is then applied to select collision scenarios. Applied examples to a double hull oil tanker are presented to demonstrate the applicability of the developed method.

Hazard Identification and Probablistic Scenario Selection for Shipship Collision Accidents

2014 ◽  
Vol 156 (A1) ◽  
Keyword(s):  
Sampling Technique ◽  
Hazard Identification ◽  
Probability Density Distribution ◽  
Collision Risk ◽  
Near Misses ◽  
Different Types ◽  
Design Loads ◽  
Ship Collision ◽  
Selection For ◽  
Accident Scenarios

In collision risk-based design frameworks it is necessary to accurately define and select a set of credible scenarios to be used in the quantitative assessment and management of the collision risk between two ships. Prescriptive solutions and empirical knowledge are commonly used in current maritime industries, but are often insufficient for innovation because they can result in unfavourable design loads and may not address all circumstances of accidents involved. In this study, an innovative method using probabilistic approaches is proposed to identify relevant groups of ship-ship collision accident scenarios that collectively represent all possible scenarios. Ship-ship collision accidents and near-misses recently occurred worldwide are collated for the period of 21 years during 1991 to 2012. Collision scenarios are then described using a set of parameters that are treated individually as random variables and analysed by statistical methods to define the ranges and variability to formulate the probability density distribution for each scenario. As the consideration of all scenarios would not be practical, a sampling technique is applied to select a certain number of prospective collision scenarios. Applied examples for different types of vessels are presented to demonstrate the applicability of the method.

HAZARD IDENTIFICATION AND PROBABLISTIC SCENARIO SELECTION FOR SHIP- SHIP COLLISION ACCIDENTS

2021 ◽  
Vol 156 (A1) ◽  
Author(s):  
S. A. M. Youssef ◽  
Y. S. Kim ◽  
J. K. Paik ◽  
F. Cheng ◽  
M. S. Kim
Keyword(s):  
Sampling Technique ◽  
Hazard Identification ◽  
Probability Density Distribution ◽  
Collision Risk ◽  
Near Misses ◽  
Different Types ◽  
Design Loads ◽  
Ship Collision ◽  
Selection For ◽  
Accident Scenarios

In collision risk-based design frameworks it is necessary to accurately define and select a set of credible scenarios to be used in the quantitative assessment and management of the collision risk between two ships. Prescriptive solutions and empirical knowledge are commonly used in current maritime industries, but are often insufficient for innovation because they can result in unfavourable design loads and may not address all circumstances of accidents involved. In this study, an innovative method using probabilistic approaches is proposed to identify relevant groups of ship-ship collision accident scenarios that collectively represent all possible scenarios. Ship-ship collision accidents and near-misses recently occurred worldwide are collated for the period of 21 years during 1991 to 2012. Collision scenarios are then described using a set of parameters that are treated individually as random variables and analysed by statistical methods to define the ranges and variability to formulate the probability density distribution for each scenario. As the consideration of all scenarios would not be practical, a sampling technique is applied to select a certain number of prospective collision scenarios. Applied examples for different types of vessels are presented to demonstrate the applicability of the method.

Toward a New Procedure for the Quantitative Risk Assessment of Double Hull Oil Tankers in Collisions

2015 ◽  
Author(s):  
Samy Adly Mansour Youssef ◽  
Serdar Turgut Ince ◽  
Yang Seop Kim ◽  
Muhammad Faisal ◽  
Jung Kwan Seo ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Residual Strength ◽  
Probabilistic Approach ◽  
Bending Moment ◽  
Quantitative Risk Assessment ◽  
Design Stage ◽  
Loading Ratio ◽  
Ship Collision ◽  
Oil Tankers ◽  
Double Hull

In recent decades, the number of ships increased substantially and it is still expected to continue to increase. Collision risk is one of the most serious accidents that can lead to severe consequences, such as casualty, property damage and environmental pollution. According to the statistics, it is found that the developments in collision avoidance systems and the related regulations have not contributed much to prevent the collision accidents. The aim of the present study is to develop a new methodology for the quantitative risk assessment of double–hull oil tankers. Within the framework of the methodology, a probabilistic approach is introduced to define a relevant set of ship–ship collision scenarios by treating the accidental influencing parameters as random variables. The collision frequency is calculated for each of the selected collision scenarios by considering a double–hull oil tanker collided with different types of striking ships. To predict the resulting collision damage to the struck ship, numerical simulations are conducted for each scenario by performing nonlinear finite element analyses. Based on the calculated risks, exceedance curves are established that can be used to define the collision design loads in association with various design criteria. In addition, to give a more complete picture of the risk assessment, a new method is proposed for assessing the risk of ship’s hull collapse following a collision. The results are formulated in terms of the residual strength index (RSI) and the loading ratio to produce the relationship between residual strength (R) and loading ratio of horizontal bending moment to vertical bending moment (L) and design formulations for predicting the RSI of damaged ship hulls are derived in an empirical manner. As an applied example, a hypothetical Suezmax–class double hull tanker is considered as a struck ship. Collision risks to asset and the environment are assessed. It is considered that the developed methodology can be useful in the early design stage of oil tankers.

A Phenomenological Theory of Socioeconomic Systems with Spatial Interactions

1982 ◽  
Vol 14 (7) ◽  
pp. 869-888 ◽  
Author(s):  
P F Lesse
Keyword(s):  
Lagrange Multipliers ◽  
Average Cost ◽  
Phenomenological Theory ◽  
Traffic Flows ◽  
Spatial Interactions ◽  
Practical Application ◽  
Density Distributions ◽  
Expected Values ◽  
Probability Density Distributions ◽  
The Relationship

This paper deals with a class of models which describe spatial interactions and are based on Jaynes's principle. The variables entering these models can be partitioned in four groups: (a) probability density distributions (for example, relative traffic flows), (b) expected values (average cost of travel), (c) their duals (Lagrange multipliers, traffic impedance coefficient), and (d) operators transforming probabilities into expected values. The paper presents several dual formulations replacing the problem of maximizing entropy in terms of the group of variables (a) by equivalent extreme problems involving groups (b)-(d). These problems form the basis of a phenomenological theory. The theory makes it possible to derive useful relationships among groups (b) and (c). There are two topics discussed: (1) practical application of the theory (with examples), (2) the relationship between socioeconomic modelling and statistical mechanics.

Accuracy of Failure Criteria Commonly Used for Ship Collision Simulations

2018 ◽  
Author(s):  
R. Villavicencio ◽  
Bin Liu ◽  
Kun Liu
Keyword(s):  
Finite Element ◽  
Failure Criteria ◽  
Small Scale ◽  
Finite Element Models ◽  
Impact Loads ◽  
Large Scatter ◽  
Element Analysis ◽  
Advantages And Disadvantages ◽  
Ship Collision ◽  
Double Hull

The paper summarises observations of the fracture response of small-scale double hull specimens subjected to quasi-static impact loads by means of simulations of the respective experiments. The collision scenarios are used to evaluate the discretisation of the finite element models, and the energy-responses given by various failure criteria commonly selected for collision assessments. Nine double hull specimens are considered in the analysis so that to discuss the advantages and disadvantages of the different failure criterion selected for the comparison. Since a large scatter is observed from the numerical results, a discussion on the reliability of finite element analysis is also provided based on the present study and other research works found in the literature.

Assembly variation analysis of complicated products based on rigid–flexible hybrid vector loop

2018 ◽  
Vol 233 (10) ◽  
pp. 2099-2114 ◽  
Author(s):  
Zhenyu Liu ◽  
Shien Zhou ◽  
Chan Qiu ◽  
Jianrong Tan
Keyword(s):  
Probability Density ◽  
Loop Model ◽  
Feature Points ◽  
Variation Analysis ◽  
Manufacturing Error ◽  
Density Distributions ◽  
Mechanical Products ◽  
Flexible Parts ◽  
Probability Density Distributions ◽  
Product Assembly

The performance of mechanical products is closely related to their key feature errors. It is essential to predict the final assembly variation by assembly variation analysis to ensure product performance. Rigid–flexible hybrid construction is a common type of mechanical product. Existing methods of variation analysis in which rigid and flexible parts are calculated separately are difficult to meet the requirements of these complicated mechanical products. Another methodology is a result of linear superposition with rigid and flexible errors, which cannot reveal the quantitative relationship between product assembly variation and part manufacturing error. Therefore, a kind of complicated products’ assembly variation analysis method based on rigid–flexible vector loop is proposed in this article. First, shapes of part surfaces and sidelines are estimated according to different tolerance types. Probability density distributions of discrete feature points on the surface are calculated based on the tolerance field size with statistical methods. Second, flexible parts surface is discretized into a set of multi-segment vectors to build vector-loop model. Each vector can be orthogonally decomposed into the components representing position information and error size. Combining the multi-segment vector set of flexible part with traditional rigid part vector, a uniform vector-loop model is constructed to represent rigid and flexible complicated products. Probability density distributions of discrete feature points on part surface are regarded as inputs to calculate assembly variation values of products’ key features. Compared with the existing methods, this method applies to the assembly variation prediction of complicated products that consist of both rigid and flexible parts. Impact of each rigid and flexible part’s manufacturing error on product assembly variation can be determined, and it provides the foundation of parts tolerance optimization design. Finally, an assembly example of phased array antenna verifies effectiveness of the proposed method in this article.

scholarly journals A new Description of Probability Density Distributions of Polar Mesospheric Clouds (PMC)

2018 ◽  
Author(s):  
Uwe Berger ◽  
Gerd Baumgarten ◽  
Jens Fiedler ◽  
Franz-Josef Lübken
Keyword(s):  
Probability Density ◽  
Mass Density ◽  
Particle Radius ◽  
Number Density ◽  
Data Set ◽  
Statistical Probability ◽  
Polar Mesospheric Clouds ◽  
Density Distributions ◽  
Mesospheric Clouds ◽  
Probability Density Distributions

Abstract. In this paper we present a new description about statistical probability density distributions (pdfs) of Polar Mesospheric Clouds (PMC) and noctilucent clouds (NLC). The analysis is based on observations of maximum backscatter, ice mass density, ice particle radius, and number density of ice particles measured by the ALOMAR RMR-lidar for all NLC seasons from 2002 to 2016. From this data set we derive a new class of pdfs that describe the statistics of PMC/NLC events which is different from previously statistical methods using the approach of an exponential distribution commonly named g-distribution. The new analysis describes successfully the probability statistic of ALOMAR lidar data. It turns out that the former g-function description is a special case of our new approach. In general the new statistical function can be applied to many kinds of different PMC parameters, e.g. maximum backscatter, integrated backscatter, ice mass density, ice water content, ice particle radius, ice particle number density or albedo measured by satellites. As a main advantage the new method allows to connect different observational PMC distributions of lidar, and satellite data, and also to compare with distributions from ice model studies. In particular, the statistical distributions of different ice parameters can be compared with each other on the basis of a common assessment that facilitate, for example, trend analysis of PMC/NLC.

Sign in / Sign up

Export Citation Format

Share Document