Risk dynamics for marine systems:towards a bio-inspired framework for dynamic risk assessment

The development of innovative, complex marine systems, such as autonomous ship concepts, has led to risk-based approaches indesign and operation that provide safety level quantification and continuous risk assessment. The existing approaches to dynamicrisk assessmentmainly aim at updating accident probabilities for specific risk scenarios, based on knowledge of system operation andfailure, aswell as on past accident and failure information. However, for innovative marine systems that include complex interactions,our ability to identify anything that might go wrong is very limited, which may lead to unidentified risks, and failure data may not beavailable. This paper presents the foundations of a framework for dynamic risk assessment, which is equally applicable to mannedand autonomous ships and mainly relies on information about the safe operational envelope and real-time information regardingdeviations from safety. Inspiration is drawn from how the biological immune system identifies the risk of infection in a dynamicenvironment. The objective is to show the feasibility and benefits of our approach for quantifying the operational risk of marinesystems. This paper provides the conceptual basis for developing ship specific applications and describes a process for dynamic riskassessment that is methodologically based on artificial immune systems. To demonstrate the implementation of our framework, wedescribed, an illustrative example that involves a ship in a grounding scenario. The results show that the bio-inspired assessmentprocess and risk description can reflect the changes of the risk level of a marine system.

Changes of citrus climate risk in subtropics of China

Based on the citrus temperature, precipitation, sunlight and climate risk degree, the article divides subtropics of China into three types： the low risk region, the moderate risk region and the high risk region. The citrus temperature risk increases with increasing latitude （except for the western mountainous area of subtropics of China）. The citrus precipitation risk in the central part of subtropics of China is higher than that in the northern and western parts. The distributions of citrus sunlight risk are not consistent to those of the citrus precipitation risk. The citrus climate risk is mainly influenced by temperature. There is latitudinal zonal law for the distribution of the climate risk, that is, the climate risk increases with increasing latitude At the same time the climate risk in mountainous area is high and that in eastern plain area is low. There are differences in the temporal and spatial changes of the citrus climate. In recent 46 years, the citrus climate risk presents a gradual increasing trend in subtropics of China, especially it has been increasing fast since the 1980s. Because of the global warming, the low risk region in the eastern and southern parts has a gradual decreasing trend, however, the high risk region in the northern and western parts has an increasing trend and the high risk region has been extending eastward and southward. The article analyses the distribution of the citrus climate risk degree of reduction rates of 〉10%, 〉20% and 〉30% in subtropics of China, and studies their changes in different time periods. Results show that the risk is increasing from southeast to northwest.