日本航海学会論文集 Vol. 136(2017)

Future transition from traditional air traffic control to trajectory-based air traffic management is now discussed. Accurate trajectory prediction is indispensable for trajectory-based management. We developed a regression model to predict the flight time of flights bound for Tokyo international airport departing from Fukuoka airport. Aircraft are vectored to make an efficient arrival sequence to the airport in Kanto South sector. The flight time predicted by our model is the time required from the entrance of Kanto South sector to the airport. It is influenced by the decision made by controllers on the order of arrival sequence to the airport. The main repressors of our model are the modified positions of the other aircraft bound for the same runway, which are called traffic density data. The width of ninety five percent interval of prediction errors is more than three minutes narrower than that of ninety five percent interval of the original data. This shows the effectiveness of the inclusion of traffic density data as repressors, but our model still has a large prediction error, and further refinement is necessary.

Although there are not many examples that classified capsizing factors systematically, classification of capsizing factors is very important to take countermeasures to decrease capsizing accidents. In this paper, the scope was narrowed down to capsizing accidents in waves which have a high probability of becoming fatal accidents. Investigation reports of Japan Transportation Safety Board were surveyed and the capsizing factors in waves were extracted and classified. A checklist for analyzing capsizing accidents was proposed and it was applied to the accidents surveyed in this paper. As a result, factors which need countermeasures regardless of ship type and the factor which needs countermeasures specifically for fishing boats were identified. Countermeasures for those factors were also organized in this paper.

In case of a collision between a large vessel and a small craft, a compass bearing of the small craft observed from the bridge of the large vessel can appreciably change when the collision place on the hull of the large vessel is at a distance from her bridge. It means that risk of collision may sometimes exist even when an appreciable bearing change is evident. In order to investigate how the seafarers understand this phenomenon, the author has referred a report of the collision between the Japan Maritime Self-Defense Force vessel Ōsumi and pleasure boat Tobiuo published by the Japan Transport Safety Board and has made a simulator scenario. The scenario gives a moving image of a small craft approaching to the bow of a large vessel with a collision course like Ōsumi and Tobiuo. Thirty three seafarers have watched the small craft from the bridge of the large vessel reproduced by a ship-handling simulator. About half of them have misjudged that the small craft will pass the bow of the large vessel because the compass bearing of the small craft appreciably change to ahead. It is verified that seafarers can sometimes misjudge risk of collision due to appreciable bearing change.

Total area of Japanese territorial waters and exclusive economic zone (EEZ) is the sixth largest in the world. As compared with such vast sea area, Japan has been operating insufficient number of vessels and voyages for getting required data of observation and exploration in the ocean of Japanese present situation. On the other hand, the organization University-National Oceanographic Laboratory System (UNOLS)⁽¹⁾ in North America, has been operating systematic 18 survey vessels of four organizations (March, 2016), Therefore, ocean observation and exploration of the Pacific Ocean and the Atlantic Ocean has been advanced steadily. In order to steady research of ocean observation and exploration in Japan, Japanese research vessel and training ship (research vessels) belonging to national and public institutions will be good used. They have ability for ocean research and exploration potentially, and it is necessary to build up their network for smooth assignment of the research vessels. We authors propose to create database about them to understand the performance of such research vessels, crew, regular quay, operational performance and operating environment, etc., and discuss research vessels operating network.

After the 2011 Great east Japan earthquake disaster, many reports on the tsunami profile at ports and disaster surveys on vessels moored in ports along the Pacific Ocean have been published. We also conducted surveys on the sea disasters of several large vessels such as crude oil and coal carriers by reproducing the moored vessel's behavior through a numerical simulation method on ship motions and tsunami. In a judgement of ship refuge action from ports, it is important for ship onboard and fleet management to grasp tsunami information after huge earthquake. In this paper, we have tried to find out a threshold of tsunami wave height for ship-mooring based on surveys on the observed tsunami data and the ship status in the ports during the 2011 Tohoku earthquake tsunami.

In this research, as a part of research on maritime traffic analysis for ship evacuation countermeasures at the time of the tsunami attack in Suruga Bay, the current situation of counter measure for earthquake and tsunami at fishery cooperatives are studied. It is appeared that there is no plan to give evacuation orders to ships from the fisherman's cooperative now. The ship owner or the captain has to make a decision in the event of disaster. Also, there are differences in measures against tsunami, and it turned out that there are places that are not provided such as evacuation places. Although the utilization of fishery radio is planed to use at the time of disaster occurrence, it become clear that there are fishery cooperatives that need measures, such as the location of coast stations.

The purpose of this study was to examine whether the collision avoidance judgement of seafarers is affected by each information sources, radar and visual. 22 seafarers who had onboard experience participated in the experiments using ship-handling simulator. Subjects were divided two groups, one group was conducted experiment for visual source, and another group was for radar source. This study investigated influence of each information source basis on results of their judgement, reasons why they made the decision, vessels which they paid attention to during experiments, and evaluations of their decision making by themselves. As a result, the judgements in both sources showed no differences. It was suggested that ships which the subjects paid attention to the decision making was different between each information source, even if the results of their decision were the same.

In order to maintain safe navigation, mariners are required to deal with given navigational situations. These are necessary tasks to be carried out, which constitute the workload for mariners. Accordingly, it is crucial for mariners not to get into situations where the workload is deemed to exceed the mariners' own competency. In particular, the lookout procedures for avoiding collisions with encountering vessels are affected by the number and movements of encountering vessels, which often increase the workload on mariners. Consequently, regarding the lookout procedures, deriving alternative measures for effective monitoring of encountering vessels in order to decrease the workload, could improve effectiveness of lookout by mariners with a view to achieving safe navigation. Measures for lookout consist of multiple actions such as visual observation and instrumental monitoring. However, experienced mariners judge the risk of collisions primarily based on visual observation, because they are well aware of the limitations and characteristics of information obtained from nautical instruments such as radar/ARPA. Therefore, in this paper, the authors focus on lookout especially by visual observation to derive such effective measures. As a result, by using the relation of the crossing angle of the courses and the ratio of velocity between one's own vessel and each encountering vessel, the authors propose that there is a specified area for lookout with a higher risk of collision. It is hoped that the proposed measure will provide a rational criterion for so-called “appropriate lookout” as a guide for mariners who need to improve their lookout competency.

In the marine traffic environment in recent years, the radar display of the marine traffic information has been improved due to the increasing use of AIS. This fact is certainly related to the improved safety of marine traffic. However, as still there are a large number of vessels operated by the conventional navigation instruments, it is concerned that there is a potential risk between the vessels with AIS and those without AIS. Under these circumstances, the authors set a goal to develop a method of risk assessment of ship traffic environment for the vessels with different information. As the first step of this development, we tried to make a simple model regarding the features of the distance sailed to abeam based on the radar observation data and made the first report. In this study, we report the simple model regarding the features of the distance sailed including the distance ahead.

Preventing marine accident of a small vessel like fishing vessels and pleasure boats is important for lifesaving, and it is necessary to make a contact the rescue team immediately to stop such accident. Current major way of marine accident notification is by using AIS or Satellite communication based method. Although these methods are effective for notifying, it is difficult to equip all small vessels the reasons of cost and regal obligation. We propose the marine accident preventing system for small vessels. To realize the target system, it is necessary to solve two kind of issues, such as the system design with easy installation and low cost and health condition monitoring, and transmission control with high transmission success rate. In this paper, we propose a smartphone and wearable heart beat monitoring device based system, and describe about LTE/3G communication quality in the Coastal Waters of Tokyo.

A variety of offshore power generation installations have been set in many countries. In the offing of Fukushima, one offshore floating transformer substation and three offshore floating wind turbines have been set as an empirical study to realize the world’s first Wind Farm. However, some effects on ship traffic have been concerned due to installation and collision between ships and installations might occur. In order to maintain and improve navigational safety, it is important to understand collision risks around the installations. In this paper, authors analyzed navigation conditions around the installations by AIS data to consider navigation safety. Also, collision frequencies to the installations were calculated as an index of collision risk based on the analysis of the ship traffic, and consider risks and effects caused by Wind Farm. It is found that there were collision risks because ships navigated near the installations, so that another safety measures may be needed.

About 70% of all marine accidents in 2014 are caused by small vessels, and about 40% of fishing vessels' accidents are collisions. Small vessels are not obliged to equip with AIS (Automatic Identification System), and radar is not equipped, so visual which is mainly used for grasping the circumstances surrounding own vessel. In this paper, we put two fisheye cameras on a small vessel, and make a 3 dimensional map generation system of the narrow waterway, furthermore calculate the distance to objects around own vessel from all round images. We make the map based on the bow direction image which transformed from all round image beforehand. The view area of the map is updated based on GPS to acquire during the navigation. The distance information to the object which we calculated displays the panoramic images which transformed from all round images. The distance calculation sets the domain of 16 directions for all round images and handles it in real time. We displayed them to 1 screen which supports watching, and evaluated it.

The waters facing the Marine Training and Research Center (MTRC) at the National Institute of Technology (NIT), Toyama College consist of a mixture of inflows from the Shinbori River, a timber pond and the open sea. In this study, we examine a particular current that is influenced by the combination of inflows and open seawater occurred in summer. This slow current, which flows westward at the speed of approximately 0.1-0.3 m/s, influences handling of small boats and the college training ship Wakashio-maru (231 GT) that operate from the MTRC pier. Accordingly, the authors conducted Conductivity, Temperature and Depth profiler (CTD), Electromagnetic current meter, and Acoustic Doppler Current Profiler (ACDP) observations of the marine environment of the flow in order to gain an understanding of the inflow waters such as their vertical formulations, seasonal variations, water structure, temperature, and salinity. The results of those observations revealed that the waters consisted of three layers, with the upper layer most influenced by the Shinbori River and the lower layer most influenced by the open sea. The middle layer was a mixture of both the upper and lower layers. It was also found that the borders of layers changed according to seasons, and that the flow was influenced by the tidal current at lower layer, the river water at upper layer and the topography.

Sharing a lot of information is used for mariners to confirm a ship's condition. In this study, engineer's data was focused to find a better data display form for effective ship operation. The running engine data was stoked in several months and transported via shore by communication network. Engineer's data is supposed to be used by engineers; officers also can use these effectively if data format was processed. The system which supply data was developed experimentally. Users will be helped navigational management using sharing the engine data by this system with some graphics or figures on any browser.

A survey was conducted among newly registered students at Fisheries University from July 2013 and 2014 to determine their occupational consciousness. The results follow. (1)In all, 81.6% of all newly registered students at Fisheries University said they had already decided what field they wanted to work in. We suggest that respondents had clear targets in entering the university. (2)We classified the occupations that students wanted to work in according to the middle classification in the Japanese Standard Occupational Classification of the Ministry of Internal Affairs and Communications Statistics Bureau. We analyzed how much students wanted to work in those occupations according to attribute. (3)Students with high self-efficacy had a clearer idea of the occupation that they wanted to work in.

Crew members' fatigue has been reported as the one of the causes of marine accident. It is necessary for inventing the decreasing method of the fatigue to clarify its causes. In our previous study, it was reported that crew members' standing postural motion against ship motion was probably the one of the causes of physical fatigue. However effects of visual stimuli on standing postural motion were still unclear. The purpose of this study is to investigate effects of the projected images of a ship handling simulator on trainees' standing postural motion. Standing postural motion was evaluated by measuring linear and angular accelerations at the head and waist, exercise load, and motion of the center of gravity (COG). Six participants looked at three kinds of image (1: image without wave, 2: 3 m height wave and 12 s wave periods, 3: 3 m height wave and 8 s wave periods). Mean values of total length of COG at image condition 2 and 3 increased compared with the length at the image condition 1. When the image condition was 3, mean value of the median frequency of horizontal direction was higher than the frequency of image condition 1. We thus found possibility that the projected images cause the standing postural motions of trainees.

The causes of crew members' fatigue have been still unclear, though their fatigue was reported as the one of the causes of marine accident. In our previous study, we found that passengers had an exercise load attributable to their postural motion caused by their postural control. However, the muscles that caused postural motion were not clarified. This study investigates the behavior of passengers' postural control against ship motion using surface electromyogram (EMG). Behavior of postural control was evaluated by linear and angular accelerations, exercise load, and muscle activity. Muscle activity was calculated by integrating the surface EMG of the soleus, the vastus lateralis, the lumbar paraspinals and the cervical paraspinals. In addition, regularized muscle activities were calculated by dividing muscle activities at sitting or standing posture by minimum value of these activities in each posture. When passengers were standing, muscle activities of the soleus and the vastus lateralis were larger than the activities that they are sitting posture. We thus found possibility that passengers controlled their postures by using lower limbs.

Aging current active seafarers and a shortage of new recruits has become an obvious problem throughout the industry in Japan. The Maritime Bureau of the Ministry of Land, Infrastructure, Transport and Tourism(MLIT) has recommended the system of grouping small coastal shipping companies by utilizing ship management companies to solve these problems. In addition, the MLIT provides the guidelines for ship management and for evaluating the management system. However, under the circumstances where the effective jobs-to-applications ratio of coastal seafarer in 2015 will become twice and a shortage of seafarers will be serious, grouping through ship management companies has not so progressed as expected. The purpose of this research is to elucidate the reason why ship management is difficult to establish management system as a type of business in coastal shipping, and to propose effective measures to resolve it.

The aim of this paper as a pre-stage to develop a system that can reduce the burden of ship operators classify obstacles from voyage environment images using neural network and HOG (Histogram of Oriented Gradient). Make a comparison and study with results of the obstacle classification by deep learning. We propose the obstacle classification method using the time series information, carry out the evaluation and study to classify obstacles from a river navigation video. The results are summarized as follows: (1)It was automatic classification for voyage bridge images into nine categories. (2)We conducted image classification experiments on captured images from a ship. We were obtained good correct answer rate and specific rate in the case of using HOG and neural network. (3)We conducted obstacle classification experiments using a river navigation video. We were obtained the correct answer rate of about 50 percent. (4)When the case of using time series information was obtained a good correct answer rate than not using time series information.

Certain types of automation technology for navigation supporting is widely accepted in maritime industries. Furthermore, interest in autonomous ship operation has been growing from the view point of safety requirement. Tokyo University of Marine Science And Technology (TUMSAT) has developed a semi-autonomous ship which is operated remotely using long range Wi-Fi and can autonomously operate under conditions of wireless link disconnect. Throughout the development and operation planning process, discussions have been held between TUMSAT and government authorities relating to the establishment of laws and regulations to govern the operation of remotely controlled and autonomous marine vessels. In this paper, case studies and legal issues to be solved by collaboration of legal and engineering are presented.