Wyniki wyszukiwania - BazTech

1

Use of fuzzy fault tree analysis and noisy-OR gate bayesian network for navigational risk assessment in Qingzhou Port

Zhao C., Wu B., Yip T. L., Lv J.

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

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2021

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Vol. 15 No. 4

765--771

EN

Collisions and groundings account for more than 80% among all types of maritime accidents, and risk assessment is an essential step in the formal safety assessment. This paper proposes a method based on fuzzy fault tree analysis and Noisy-OR gate Bayesian network for navigational risk assessment. First, a fault tree model was established with historical data, and the probability of basic events is calculated using fuzzy sets. Then, the Noisy-OR gate is utilized to determine the conditional probability of related nodes and obtain the probability distribution of the consequences in the Bayesian network. Finally, this proposed method is applied to Qinzhou Port. From sensitivity analysis, several predominant influencing factors are identified, including navigational area, ship type and time of the day. The results indicate that the consequence is sensitive to the position where the accidents occurred. Consequently, this paper provides a practical and reasonable method for risk assessment for navigational accidents.

2

Predicting the shipping market by spreads of timecharter rates

Yip T. L.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2018

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nr 53 (125)

9--16

EN

This paper has explored the predictability of spreads between long-term and short-term timecharter rates on spot freight rates. The spread between long-term and short-term rates (or the slope of the yield curve) is often used as a leading economic indicator of economic activities. This concept has been extended to the shipping market in this paper and the probability that the spot freight rate will increase or decrease has been determined. Using the spread between the timecharter rates on long-term and short-term charter contracts, the direction of spot freight rates has been predicted with the dynamic probit model, which is used to estimate the probability of discrete events. Evidence has been drawn from Panamax dry bulk ships for future weekly, quarterly and biyearly changes of spot freight rates. While the dynamic probit model has shown moderate predictive power, the weekly model has shown that the market has a relatively longer memory than the quarterly and biyearly models.

3

Passage Planning System in Ports: An overview

Yip T. L.

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

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2015

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Vol. 9, no. 4

483-487

EN

A conceptual model is proposed to monitor marine traffic through precautionary areas, which can provide us with a systematic control of passage planning in ports. On one hand, vessel traffic control has its special features and is fundamentally different from highway, air and pedestrian traffic control. The existing traffic control systems cannot be simply extended to vessel traffic control without addressing marine traffic features. On the other hand, existing vessel traffic control focuses on one ship or two ships but does not address the flows of marine traffic.

4

A Marine Traffic Flow Model

Yip T.L.

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

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2013

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Vol. 7, no. 1

109--113

EN

A model is developed for studying marine traffic flow through classical traffic flow theories, which can provide us with a better understanding of the phenomenon of traffic flow of ships. On one hand, marine traffic has its special features and is fundamentally different from highway, air and pedestrian traffic. The existing traffic models cannot be simply extended to marine traffic without addressing marine traffic features. On the other hand, existing literature on marine traffic focuses on one ship or two ships but does not address the issues in marine traffic flow.