• Title/Summary/Keyword: Risk of Collision

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Airspace Safety Assessment for Implementation of the Japanese Domestic Reduced Vertical Separation Minimum

  • Amai, Osamu;Nagaoka, Sakae
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.435-440
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    • 2006
  • The Reduced Vertical Separation Minimum (RVSM), which is the reduced minimum from 2,000 ft to 1,000 ft at flight levels (FL) between 290 and FL410 inclusive, was implemented in 30 September 2005 within the Japanese domestic airspace. Prior to the implementation, safety assessment for the airspace in assumed RVSM environments was carried out. Some model parameter values of collision risk model were estimated using flight plan (progress) data and radar data. An estimate of vertical collision risk including operational risk was calculated using these together with given parameter values. The results obtained from this analysis are as follows. (1) Contribution of the vertical collision risk for the crossing routes is about 9 percents of the total technical risk. (2) The estimate of the collision risk is $4.1{\times}10^{-9}$ [fatal accidents / flight hour] and the value is smaller than a maximum allowable level of collision risk, i.e. $5{\times}10^{-9}$ [fatal accidents / flight hour], called the Target Level of Safety.

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A Study on the Practical Means to Prevent Collision at Sea - Through risk management theory -

  • Lee, Ok-Yong;Grewal, Devinder;Cahoon, Stephen
    • Journal of Navigation and Port Research
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    • v.31 no.4
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    • pp.295-307
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    • 2007
  • The statistics of Korean Maritime Safety Tribunal and Japan Marine Accidents Inquiry Agency shows that the major muses of collision at sea are Improper lookout and Non-compliance with marine traffic rules. Those two muses are occupying more than 70% of collision, and it's clear that those muses are undoubtedly closely related to simple human error. In this paper we tried to find out the root muses of this kind of human error of OOWs(officers on watch) through risk identification method and studied how to tackle them via risk control theory. In conclusion, the measures studied in this paper could be applied to help OOWs avoid their own human error as well as be used in shipping company for their fleets' safety management.

A Study on the Threshold of Avoidance Sector in the New Evaluation of Collision Risk (신 충돌위험도평가에서 피항구역의 문턱값 결정에 관한 연구)

  • Jeong Tae-Gweon
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2004.11a
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    • pp.57-60
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    • 2004
  • Evaluating the risk of collision quantitatively plays a key role in developing the expert system of navigation and collision avoidance. This study analysed thoroughly how to determine the thresholds as described in the new evaluation of collision risk using sech function, and developed the appropriate equation as applicable.

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A Study on a New Evaluation of Collision Risk and the Problems Involved

  • Jeong, Tae-Gweon
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2004.08a
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    • pp.146-154
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    • 2004
  • Evaluating the risk of collision quantitatively plays a key role in developing the expert system of navigation and collision avoidance. This study suggested and developed a new approach to the evaluation by using the sech function as an alternative to the existing methods of appraising the collision risk. This study also investigated and built up theoretically how to determine the gradient coefficients in this approach and suggested the appropriate values as much as applicable. Finally this study analyzed thoroughly how to determine the threshold function of avoiding time and developed the appropriate equation.

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A Study on Determination of Gradient Coefficients in the New Evaluation of Collision Risk (신 충돌위험도평가의 기울기계수 결정에 관한 연구)

  • Jeong, Tae-Gweon
    • Journal of Navigation and Port Research
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    • v.27 no.4
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    • pp.351-357
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    • 2003
  • Evaluating the risk of collision quantitatively plays a key role in developing the expert system of navigation and collision avoidance. This study analysed theoretically and thoroughly how to determine the gradient coefficients as described in the new evaluation of collision risk using sech function, and suggested the appropriate values as applicable.

A Study on the Degree of Collision Risk with Relative Bearing at CPA (최근접점 상대방위에 따른 선박충돌위험알고리즘 개발에 관한 연구)

  • Lee, Jin-Suk;Jung, Min;Song, Chae-Uk
    • Journal of Navigation and Port Research
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    • v.39 no.6
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    • pp.493-498
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    • 2015
  • When VTSOs(Vessel Traffic Service Operators) determine the degree of collision risk of two vessels, they consider comprehensively information about each vessel's course, speed, DCPA, TCPA and encountering situation. In this study, we proposed an algorithm in which two relative bearings as information about two vessel's encountering situation are used to evaluate the degree of collision risk. In order to verify whether the proposed algorithm is reasonable, we set twenty encountering situations and conducted a survey of collision risk on fifty three VTSOs about those situations. By comparing the degrees of collision risk with the proposed algorithm to the results of the survey, we found that relative bearing at CPA is very important factor for VTSO to recognize the level of collision risk when two vessels are in encountering situation.

A Study on the Risk of Collision and the Due to Regard of Watchkeeping Officer at Sea (해상교통법상 균형의 위헙과 항해당직자의 주의의무에 관한 고찰 -국제규칙과 판례.재결을 중심으로-)

  • 황석갑
    • Journal of the Korean Institute of Navigation
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    • v.17 no.1
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    • pp.1-15
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    • 1993
  • According to careful study on the COLREGS, 1972, we can easily find out a main point that is to eliminate risk of collision at sea through exercising due regard to all danger of navigation and collision and to any special circumstances including the limitation of the vessels involved, or precaution which may be required by the ordinary practice of seamen. This paper, therefore, aims to clarify legal concept concerning the risk of collision so as to easier assimilate and understand by all mariner before being presented with a situation of danger in realty. After such a forethought and understanding the mariner will be in a position timely to implement the due regard or precaution to avoid collision by himself. For the purpose of good guidance, comprehensive legal practices of collision avoidance are adequately summarized by foreign and domestic cases.

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Development and Operation Status of Space Object Collision Risk Management System for Korea Aerospace Research Institute (KARI) (한국항공우주연구원 우주물체 충돌위험 관리시스템 개발 및 운영현황 )

  • Jaedong Seong;Okchul Jung;Youeyun Jung;Saehan Song
    • Journal of Space Technology and Applications
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    • v.3 no.3
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    • pp.280-300
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    • 2023
  • This paper includes the development and operational status of the space object collision risk management system operated by the Korea Aerospace Research Institute. Currently, it monitors 6 low-orbit satellites and 3 geostationary satellites for collision risks 24 hours, enabling prompt collision avoidance maneuvers to ensure safe and stable operations. Since Chinese anti-satellite test (ASAT) in 2007, the monitoring of collision risks between space objects and operational satellites has been taken seriously, leading to the development of various collision risk management systems to respond quickly and efficiently to such situations. This paper provides an introduction to the space object collision risk management system developed from 2007 to the present, the current status of artificial space objects around Earth, and the system currently in operation. Additionally, it outlines future prospects and plans for the system.

Dual-Mode Framework for Space Object Collision Risk Assessment (우주 물체 충돌 위험 분석을 위한 이중 모드 프레임워크)

  • Kim, Siwoo;Lee, Jinsung;Choi, Eun-Jung;Cho, Sungki;Ahn, Jaemyung
    • Journal of Space Technology and Applications
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    • v.2 no.1
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    • pp.13-29
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    • 2022
  • Recently, the number of space objects around the Earth has increased rapidly, necessitating systematic space risk management. This paper proposes a dual-mode framework for assessing the risk of collision between space objects. The proposed framework consists of microscopic and macroscopic modes. The former focuses on one-to-one collision events, and the latter assesses the overall collision risk inside a cell located in space. Two risk assessment case studies using the proposed two modes demonstrate the effectiveness of the proposed framework.

Design of the Model for Predicting Ship Collision Risk using Fuzzy and DEVS (퍼지와 DEVS를 이용한 선박 충돌 위험 예측 모델 설계)

  • Yi, Mira
    • Journal of the Korea Society for Simulation
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    • v.25 no.4
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    • pp.127-135
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    • 2016
  • Even thought modernized marine navigation devices help navigators, marine accidents has been often occurred and ship collision is one of the main types of the accidents. Various studies on the assessment method of collision risk have been reported, and studies using fuzzy theory are remarkable for the reason that reflect linguistic and ambiguous criteria for real situations. In these studies, collision risks were assessed on the assumption that the current state of navigation ship would be maintained. However, navigators ignore or turn off frequent alarms caused by the devices predicting collision risk, because they think that they can avoid the collisions in the most of situations. This paper proposes a model of predicting ship collision risk considering the general patterns of collision avoidance, and the approach is based on fuzzy inference and discrete event system specification (DEVS) formalism.