Using near miss data detected from non-accident information to analyse marine traffic risk can alleviate some of the limitations of accident-based methods. A model based on an arena for detecting scenes of near miss is proposed to detect comprehensively those ship encounters with potential collision risk. To eliminate the influence of data sampling frequency on the detection of scenes of near miss, a single near miss is defined as the whole progress of traffic state from the time the target ship sails into the arena of the subject ship to the time it leaves the arena of the subject ship. To research the geographical distribution characteristics of marine traffic risk, first, a statistical model for the scenes of near miss based on the water grid method is proposed, and then a macroscopic collision risk model based on near miss is developed. The geographical distribution characteristics of marine traffic risk in the Bohai Sea are analysed, and the water areas of high marine traffic risk are obtained. The findings can provide theoretical support for marine safety management.

When preparing radiation treatment, the prescribed dose and irradiation geometry must be translated into physical machine parameters. An error in the calculations or machine settings can negatively affect the intended treatment outcome. Analysing incidents originating in the treatment preparation chain makes it possible to find weak links and prevent treatment errors. The aim of this work is to study the effectiveness of a multilayered error prevention system by analysing both near misses and actual treatment errors.

The system utilised in this centre has primary and secondary checking as two layers of independent calculation-checking. We studied near misses as well as the actual errors which were not picked up by these pre-treatment checking procedures over a year (5154 treatment plans). Furthermore, the primary checking was studied in more detail over three years (15,386 treatment plans) to increase the statistical accuracy.

For each reported actual treatment error originating in the treatment preparation chain, 13.8 near misses were found by primary and secondary checking and thereby prevented from becoming actual errors. The total frequency of near misses was 34.4 per 1000 treatment plans. The primary checkers reported 23 types of errors for manual treatment plans (without dose distribution) and 30 types of errors for computer plans. Computer plans also showed a near miss rate that was 42% higher than for manual plans. The high ratio of near misses per actual error demonstrates an effective error prevention system, independent of the quality of the initial treatment preparation. Complex treatment plans were shown to be particularly error-prone, thereby requiring extra vigilance when checking.

In a near miss experience, a person learns anxiety despite the fact that the feared outcome does not actually occur. Theories based on S-R links or direct encoding of emotional memories do not provide a good model of near miss learning because they fail to account for informational variables. An alternative cognitive model is outlined, based on expectancy of an inferred negative outcome. The model is applied to posttraumatic stress disorder, in which the critical feared outcome is often death, and panic disorder, in which a near miss inference may protect expectancies of harm from disconfirmation. Unlike direct emotional encoding models, the inferential/expectancy model provides multiple cognitive targets for treatment. Near miss learning may be usefully distinguished from other pathways to anxiety, and warrants further experimental investigation.