日本財団 図書館

共通ヘッダを読みとばす


Top > 産業 > 運輸.交通 > 成果物情報

Conference Proceedings Vol. I, II, III

 事業名 海事シミュレーションと船舶操縦に関する国際会議の開催
 団体名 日本船舶海洋工学会 注目度注目度5


Quantitative Estimation of Safety Degree on Ship's Operations
Shin MURATA (National Institute for sea Training, Japan)
Hiroaki KOBAYASHI (Tokyo university of Mercantile Marine)
 
 Abstract: It is said that more than 80 % of the cause for marine accidents is human error. And for prevention of marine accidents, all sorts of measures toward human error have been executed in all over the world. However, the number of marine accidents is not tending downward. Therefore, authors paid attention to human insufficient behavior treated as human error. Human insufficient behavior often cause the error that lead to an accident. If we can find the condition for an occurrence of human insufficient behavior and its characteristics, it is possible to estimate safety degree on ship's operations. In this paper, the condition for an occurrence of human insufficient behavior was analyzed by determination of a quantity of human competency. Furthermore, safety degree on ship's operations was estimated quantitatively using extracted characteristic of human insufficient behavior.
 
1. INTRODUCTION
 It is necessary to maintain the balance between required competency by navigational environment and attainable competency by mariner for safer ship 's operations. And it has been found that mariner's insufficient action was apt to occur when this balance was broken. In this study, this action has been called human insufficient behavior. Human insufficient behavior has been defined as human action that dose not appropriate to the objective. On the other hand, it is necessary to determine the quantity of required competency by navigational environment and attainable competency by mariner for verification of proposal concept. In this paper, determinations of the quantity of required and attainable competency were executed, and the condition for an occurrence of human insufficient behavior was discussed. Moreover, safety degree on ship's operations was estimated quantitatively.
 
2. DETERMINATION OF A QUANTITY OF REQUIRED COMPETENCY
2.1 Relation between a Quantity of the Task and Elemental Task
 
 In this study, required competency means a quantity of the task that was required by navigational environment. And the task means ship-handling technique. It was already clarified that ship-handling technique could be systematized by combination of 9 elemental techniques. And each elemental technique is subdivided into the contents corresponding to elemental task. Therefore, the relation between a quantity of the task and a quantity of elemental task was formulated.
 
 Formula (1) indicates the relation between a quantity of the task and elemental tasks
 
 
Where Q: Quantity of the task
J: Quantity of elemental tasks
N: The number of elemental task
 
 In formula (1), Q means a quantity of the task, J means a quantity of elemental tasks, and N means the number of elemental task. The quantity of the task can be calculated by the sum of each quantity of elemental task.
 
2.2 Conversion of the Task into Time
 
 In previous section, it was indicated that a quantity of the task could be calculated by formula (1). However how to determine a quantity of the elemental task must be indicated. In general, it is said that it takes a short time to accomplish an easy elemental task, while it takes a long time to accomplish a difficult elemental task for inexperienced mates. However, it has known that Captain or experienced mates can accomplish a difficult elemental task within a given time in most of cases. Therefore, we made a proposal to convert the consumption of the mean time to accomplish an elemental task on 1st grade navigation officers into a quantity of an elemental task. And the consumption of the mean time to accomplish each elemental task was measured on 1st grade navigation officers. Elemental techniques corresponding to elemental task are selected as follows; (1) Positioning, (2) Planning, (3) Maneuvering and (4) Communication. These techniques are placed in important tasks on practical ship's operations. Meanwhile, each elemental technique is subdivided into 5 ranks as the difficulty of each elemental technique to be done. Details of each elemental task are indicated in Table 1. In Table 1, the large number of rank is expressed as high difficulty. And measurement conditions for each task are indicated in Table 2. Experiments for measurement of a time consumption to accomplish elemental task were carried out at simulator center in Tokyo University of Mercantile Marine. And subjects of experiments are 5 experienced mates who have 1st grade license. Before carrying out of experiments, an experimental condition was shown to all subjects. It is that all subjects have to give full play to own perfect competency without spare time. On the other hand, objects for measuring of compass bearing are appointed in an elemental technique "Positioning". And autopilot system was adopted in elemental technique "Maneuvering", and the contents of conversation by VHF radio were also appointed in elemental technique "Communication". Moreover, container vessel of 280m in length was used as own vessel in each simulation, and bulk carrier of 330m in length was also used as own vessel in elemental technique "Maneuvering" of rank 2, 3, and 4.
 
2.3 Results of experiments and analysis
 
 The time consumption for accomplishment on each elemental task is indicated in Fig.1 (a)-(d). Vertical axis in each figure shows the time consumption, namely, a quantity of elemental task, and horizontal axis show the rank of elemental task. All values are given by the second. And vertical lines drawn on each symbols show the deviation value. The circles in Fig.1 (a) indicate mean time on all experimental results of "Positioning", the triangles in Fig.1 (b) indicate mean time on all experimental results of "Planning", and the squares in Fig.1 (c) indicate mean time on all experimental results of "Maneuvering" except rank 5. The measurement of rank 5 in "Maneuvering" was canceled because the defectiveness was found in measurement condition. And the diamonds in Fig.l (d) also indicate mean time on all experimental results of "Communication". As the results of experiments, it was confirmed that elemental task could be quantified by time conversion, and measured competency on experienced mates was not dispersing. Moreover, the normalization of the difficulty on each elemental task was executed. The rank-1 in "Communication" was chosen as a base because it was found that the dispersion of competency was very little. Fig.2 indicates the normalization of a quantity of elemental task. In Fig, 2, vertical axis shows the unit of unified elemental task. And horizontal axis shows each rank of unified elemental task. From the value in Fig.2, the weight of each elemental task can be obtained.
 
Table 1 Detail of each elemental task
  Elemental technique Rank 1 Rank 2 Rank 3 Rank 4 Rank 5
1 Positioning Taking a fix on GPS Data Taking a fix on 2 Lines of Position (1 Compass Bearing and 1 Radar Range) Taking a fix on 3 Lines of Position (1 Compass Bearing and 2 Radar Ranges) Taking a fix on 3 Lines of Position (3 Compass bearing) Taking a fix on compass bearing include error, and Radar Information
2 Planning Making a new plan to set course from deviant position to next altering point Decision of the time to alter course in consideration of DNC from planned course Making a new plan to alter course on deviant position from planned course Decision of the time to alter course in consideration of DNC from deviant position. Making a plan to reduce own speed to point and time designate under tideway
3 Maneuvering Follow-up ship handling to next planned course Follow-up ship handling to next planned course under leeway Detection of adjusting course against strong tideway Maneuver to reduce own speed to the line designate under tideway Maneuver to reduce own speed to the point and time designate under tideway
4 Communication by VHF Radio Known opponent Radar and ARPA are usable (VS. VTS) Known opponent Radar and ARPA are usable (VS. another vessel) Unknown opponent Radar and ARPA are u sable. (VS. another vessel) Unknown opponent Radar and ARPA are usable (VS. plural vessel) Unknown opponent Radar and ARPA are unusable (VS. plural vessel)
DNC: Distance of New Course
 
Table 2 Conditions for measurement on each task
NO Elemental technique Commencement Completion
1 Positioning A point in time just measured compass bearing, Radar range or GPS Data A point in time just completed measurement of compass bearing, distance by Radar or GPS Data
A point in time just given a starting signal by observers. A point in time just entered measuring time on a chart after fix own position.
2 Planning A point in time just given a starting signal by observers. A point in time just entered planned course and other items designate on a chart
3 Maneuvering A point in time just taken rudder by auto pilot system A point in time just reached rudder angle designate by auto pilot system
A point in time just given a starting signal by observers. A point in time just reached the value designate (0.1 m/sec and under)
A point in time just operated engine telegraph to reduce own speed A point in time just reached the point or line designate (± 0.5 knots)
4 Communication by VHF Radio A point in time just talking a call to opponent by VHF radio A point in time just taken VHF radio channel from 16 to others designate
A point in time just calling again to opponent by channel designate A point in time just sending "out" to opponent by VHF radio
 
Fig.1 Required competency by navigational environment
 
[a]
 
[b]
 
[c]
 
[d]
 
Fig.2  Normalization of the required competency by navigational environment
 
3. DETERMINATION OF A QUANTITY OF ATTAINABLE COMPETENCY
3.1 Relation between Human Competency to Accomplish the Task and Elemental Task
 
 In previous section, it was found that the weight of each elemental task could be obtained by normalization of the quantity of elemental task. The relation between human competency to accomplish the task and human competency to accomplish elemental tasks indicates in Formula (2).
 
 
Where
C: Human competency to accomplish the task
 
K: Human competency to accomplish elemental tasks
 
N: The number of elemental task.
 
 In formula (2), C means human competency to accomplish the task, K means human competency to accomplish elemental tasks, and N means the number of composing task. Human competency to accomplish the task can be calculated by the sum of competency to accomplish each elemental task.
 
3.2 Conversion of Competency into Time
 
 It was already confirmed that a quantity of the task could be quantified by time consumption without spare time for accomplishment of the task in section 2.2. In this section, we made a proposal to convert the consumption of the mean time to accomplish the task on normal performance into human competency. Then, attainable competency on 5 subjects, who have 3rd grade license, was measured on each elemental task which was indicated in Table 1. At that time, the conditions for measurement and experiments were the same that was explained in section 2.2. And competency measured by experiments indicates in Fig.3 (a)-(d). Vertical axis in each figure shows the time consumption to accomplish the task designate, namely, a quantity of human competency. Horizontal axis shows the rank of elemental task. And all values are given by the second. The black circles in Fig.3 (a) indicate mean time of all experimental results of "Positioning", the black triangles in Fig.3 (b) indicate mean time of all experimental results of "Planning", and the black squares in Fig.3 (c) indicate mean time of all experimental results of "Maneuvering". And the black diamonds in Fig 3 (d) also indicate mean time of all experimental results of "Communication".







サイトに関するご意見・ご質問・お問合せ   サイトマップ   個人情報保護

日本財団会長笹川陽平ブログはこちら



ランキング
注目度とは?
成果物アクセスランキング
124位
(31,497成果物中)

成果物アクセス数
104,073

集計期間:成果物公開〜現在
更新日: 2019年10月12日

関連する他の成果物

1.MARSIM'03 開催報告
2.本会議及びワークショップ開催状況写真
3.九州における離島住民からみた交通バリアフリー化に関する調査研究?鹿児島県をモデルケースとして? 報告書
  [ 同じカテゴリの成果物 ]


アンケートにご協力
御願いします

この成果物は
お役に立ちましたか?


とても役に立った
まあまあ
普通
いまいち
全く役に立たなかった


この成果物をどのような
目的でご覧になりましたか?


レポート等の作成の
参考資料として
研究の一助として
関係者として参照した
興味があったので
間違って辿り着いただけ


ご意見・ご感想

ここで入力されたご質問・資料請求には、ご回答できません。






その他・お問い合わせ
ご質問は こちら から