IWRAP MK2 INTRODUCTION IALA Waterway Risk Assessment Programme Omar - - PowerPoint PPT Presentation

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IWRAP MK2 INTRODUCTION IALA Waterway Risk Assessment Programme Omar Frits Eriksson Dean, IALA World-Wide Academy 23/10/2017 Not Rocket Science IWRAP is Probabilistic algorithm Scenario based Quantitative approach 1974 Fujii, et al.

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23/10/2017

Omar Frits Eriksson

Dean, IALA World-Wide Academy

IWRAP MK2 INTRODUCTION

IALA Waterway Risk Assessment Programme

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Not Rocket Science

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IWRAP is

Probabilistic algorithm Scenario based Quantitative approach

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1974

Fujii, et al. “Some Factors Affecting the Frequency of Accidents in Marine Traffic.”

Journal of Navigation, Vol. 27, 1974

MacDuff, T.: “The Probability of Vessel Collisions”.

Ocean Industry, September 1974.

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1995

Pedersen, P. Terndrup: "Collision and Grounding Mechanics".

  • Proc. WEMT 1995, Copenhagen
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IWRAP Evolution

IALA Council Approves ”IWRAP Mk I” (2006) Copenhagen calibration test failure (2006) SG decides to start from scratch (2007) New software coding by Gatehouse (2008) Commercial version available (2010) IWRAP Mk2 V/5 Release (China 2017)

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IWRAP Mk2 Licensing scheme

Basic License (free to IALA members) Commercial License

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IWRAP is a

Probabilistic algorithm

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Basic Risk Equation

R = P ∙ C

R = Risk P = Probability that undesired incident occurs C = Consequences of undesired incident

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IWRAP ….. Probability / Frequency

R = P ∙ C

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IWRAP basic algorithm

1. First determine the (average) number of possible incidents, assuming that no evasive action is taken (blind navigation). 2. Then adjust this number by multiplying it with the probability that an evasive action fails (thinning with Fujii type causation factors)

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Basic Algorithm

XGnd = NGnd ∙ PC

NGnd = Number of Grounding Candidates Pc = Causation Probability XGnd = Number of Annual Groundings

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Grounding scenario

(COWI Consult , 2006)

Number of grounding candidates is proportional to the portional area under the curve times traffic volume

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Lateral Distribution of Vessels from AIS

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Assumptions

1. Geometric distribution of the ship traffic over the waterway is constant 2. Volume of traffic is constant 3. Composition of traffic is constant 4. Lateral distribution of vessels is constant 5. Causation factors are constant 6. ….. 7. …..

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Causation Factors

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Elements of Causation Probability Factors ”Human Factors”

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Elements of Causation Probability Factors ”Organisational/Structural”

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From litterature we have

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IWRAP Default Causation Probabilities

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IWRAP is

Scenario based

  • Grounding scenarios (2)
  • Allission Scenarios (2)
  • Collision Scenarios (6)
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Grounding & Allision Scenarios

Powered grounding / allision Drifting grounding / allision

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Powered grounding

(COWI Consult , 2006)

Number of grounding candidates is proportional to the portional area under the curve times traffic volume

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Powered Grounding

Analyst can set/adjust: Causation factor value For each ship type, what is the probability that the navigatior fails to make an evasive action.

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Drifting Grounding

Analyst can set/adjust: blackout frequency repair time probabilities ancoring probability and conditions drifting direction probability

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Drifting grounding

Repair time probability

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Scenarios - Collisions

Overtaking collisions Head –On collisions Crossing collisions Merging collisions Bend collisions Area collisions

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Collisions scenarios Analyst can set/adjust:

  • Causation factor values

For each ship type, what is the probability that the navigatior fails to make an evasive action.

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Area collision scenario

Can model non-AIS vessels Fishing vessel behaviour Leisure vessel behaviour Analyst can modify causation factor for each ship type

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Causation factors IALA default values

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Model Calibration

Results: Collision/ Grounding frequencies Model based on present traffic distribution and waterway geometry Run IWRAP Mk2 Compare with Historical Casualty data

Verification Calibration

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Basic Procedures

Define area to be analysed Gather sea charts, incident data Define route layout / route legs Allocate traffic to route legs Define relevant grounds as polygons Do calculation Calibrate model What-if analysis

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Share results with IALA

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Data requirements for IWRAP Analysis:

High or medium resolution AIS data Sea charts Grounding hazard information Historical facts on incident (Causation Factor adjustments)

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Stable conditions?

Incident data is historical (you want 10 years) Have the conditions changed in this period? New aids to navigation? Has volume of traffic changed? Has the traffic composition changed?

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AIS data quality

Gaps in time series? Blind spots in geographic coverage? Has the data been downsampled?

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Gaps in AIS data

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AIS coverage quality

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Downsampled AIS data

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Downsampled AIS data

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Incident data quality

Need data for calibrating your model Groundings – often to few registred Collisions – usually good Types of incidents? Positions of incidents? Types of vessels involved?

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Causation Factors

IWRAP provides default values Significant variation globally Analysts need to form their own view Need to exchange these views

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Analysts and their quality

Understand the limitations of IWRAP Understand the waterway conditions Understand waterway history Understand Causation Factors

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Risk Toolbox Wiki

http://www.iala-aism.org/wiki/iwrap/

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Thanks

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Connect: E-mail:

  • mar.eriksson@iala-aism.org

LinkedIn: Omar Frits Eriksson Twitter: OMaritime Mobile: +33 6 31 17 76 42