Takahiro Takemoto

Questionnaire Survey for Adapting Common Performance Conditions to Marine Accidents

An officer of the watch (OOW) is a qualified person with the knowledge and capabilities required to safely navigate a ship. However, many collisions occur that are caused by human errors in navigation. Eighty-four percent of collision accidents are caused by inadequate lookout. It is estimated that such accidents can be prevented if the OOW performs fully to his or her knowledge and capabilities. Many factors can reduce the OOWs reliability, so it can be difficult to specify the cause of an accident. If the cause of an accident can be specified, efficient measures can be taken. This study utilizes a human reliability analysis method to analyze marine accidents. The cognitive reliability and error analysis method (CREAM) divides background factors into nine common performance conditions (CPCs). However, the manner in which CREAM is used in the nuclear industry is not applicable to the maritime domain since the working conditions are very different. To facilitate using CREAM to analyze marine accidents, we sought advice from specialists about redefining the CPCs and their descriptions. We then adapted the dependencies between the CPCs to marine accidents based on a questionnaire survey administered to OOWs. This paper reports the results of the questionnaire survey. In addition, we discuss the dependencies between the CPCs adapted for marine accident analysis. These results confirm the essence and character of the maritime industry.

Construction of 3-Dimensional Virtual Environment Based on Photographed Image (the Acquisition and Processing of the Photographed Image)

In this study, we propose to construction of 3-dimensional virtual environment in the bay. To support construction of structure on the route of ship and a large ship’s position for arrival at the pier, it is suitable for utilizing real images. When we construct places to put ships, for example container yards, we need to think an influence toward a route of ships and surrounding environments. There are many things we cannot understand only by design drawings. Therefore, we need to watch real environments to understand the present situation more clearly. A captain probably hopes to simulate on basis of real images before arriving in a port. Then, we consider a method of virtual environmental construction.

A Characteristic of a Navigator's Situation Awareness for Crossing Ships

Many ship collisions have been caused by a navigator’s error in the situation awareness (SA) of the navigator. In congested sea areas, navigators classify ships on the basis of different priority levels. For safety measures against ship collision, it is imperative for navigators to recognize the ships with high priority levels. In previous study, navigators’ SA was measured in a ship maneuvering simulator using the Situation Awareness Global Assessment Technique (SAGAT). From the results of the previous study, we proposed a new risk category, named as “attention area,” that covers ships with high priority level in the SA of navigators. However, the extent of data for navigators’ SA was limited. Therefore, the purpose of this study is to confirm the validity of the category using additional data of navigators SA. In this study, the validity of the proposed category was confirmed, and a limit line surrounding ships with high priority levels was identified. In addition, it was evident that the category was able to detect ships with high priority level around the time when the collision avoidance was performed. http://www.transnav.eu the International Journal on Marine Navigation and Safety of Sea Transportation Volume 11

The support for using the cognitive reliability and error analysis method (CREAM) for marine accident investigation

On a ships bridge, the deck officer who has the duty of navigating and keeping watch is known as the officer of the watch (OOW). Many of the causes of accidents relate not only to the OOWs knowledge and capability, but to his or her cognitive process. The cognitive reliability and error analysis method (CREAM) is a technique for analyzing human reliability. The CREAM organizes interactions between humans and the environment by using the human-technology-organization triad. The CREAM defines common performance conditions (CPCs), the dependencies between them, and the links between antecedents and consequences, thus clarifying the background factors that affect human performance. This method has mainly been used in the nuclear industry, but since conditions change across domains, CPCs apply differently to other domains. Based on the considerations above, we have adapted CPCs to maritime collision accidents, and administered a questionnaire to OOWs for the purpose of quantifying the dependency and priority of CPCs. This paper introduces the support for the retrospective analysis of marine accidents.

Design and Implementation of High-Resolution Sea-Lane Image Texture for Marine Virtual Environment

In this paper, we propose the efficient approach for constructing virtual reality simulation of ship navigation that supports navigator. Therefore, we propose that simple constructing environments surrounding ships. Structures along the yard can easily displayed with one texture mapping on one NURBS (Non Uniform Rational B-spline) surface. Using this method, we take only 15 s to make one structure including cutting textures.

Error Detection in the Navigational Watch Based on the Behavior Analysis of Navigators

Poor lookouts, i.e. one of errors in situation awareness, are pointed out as the major cause of collisions of ships, through investigations of collision accidents. In order to evaluate safety measures for preventing collisions caused by poor lookouts, it is necessary to understand background factors, so called “contexts”, of errors in situation awareness regardless of occurrence of collisions. The purpose of this study is to point out the possible significant contexts, using a navigator’s situation awareness model. As a result, the authors point out that one of the possible significant contexts is a problem on judgment of priority levels of other ships with regard to attention.