• Title/Summary/Keyword: 자동운항

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Application of neural network for airship take-off and landing mode by buoyancy control (기낭 부력 제어에 의한 비행선 이착륙의 인공신경망 적용)

  • Chang, Yong-Jin;Woo, Gui-Ae;Kim, Jong-Kwon;Lee, Dae-Woo;Cho, Kyeum-Rae
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.2
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    • pp.84-91
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    • 2005
  • For long time, the takeoff and landing control of airship was worked by human handling. With the development of the autonomous control system, the exact controls during the takeoff and landing were required and lots of methods and algorithms were suggested. This paper presents the result of airship take-off and landing by buoyancy control using air ballonet volume change and performance control of pitch angle for stable flight within the desired altitude. For the complexity of airship's dynamics, firstly, simple PID controller was applied. Due to the various atmospheric conditions, this controller didn't give satisfactory results. Therefore, new control method was designed to reduce rapidly the error between designed trajectory and actual trajectory by learning algorithm using an artificial neural network. Generally, ANN has various weaknesses such as large training time, selection of neuron and hidden layer numbers required to deal with complex problem. To overcome these drawbacks, in this paper, the RBFN (radial basis function network) controller developed. The weight value of RBFN is acquired by learning which to reduce the error between desired input output through and airship dynamics to impress the disturbance. As a result of simulation, the controller using the RBFN is superior to PID controller which maximum error is 15M.

Study on the Evaluation of Ship Collision Risk based on the Dempster-Shafer Theory (Dempster-Shafer 이론 기반의 선박충돌위험성 평가에 관한 연구)

  • Jinwan Park;Jung Sik Jeong
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.29 no.5
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    • pp.462-469
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    • 2023
  • In this study, we propose a method for evaluating the risk of collision between ships to support determination on the risk of collision in a situation in which ships encounter each other and to prevent collision accidents. Because several uncertainties are involved in the navigation of a ship, must be considered when evaluating the risk of collision. We apply the Dempster-Shafer theory to manage this uncertainty and evaluate the collision risk of each target vessel in real time. The distance at the closest point approach (DCPA), time to the closest point approach (TCPA), distance from another vessel, relative bearing, and velocity ratio are used as evaluation factors for ship collision risk. The basic probability assignments (BPAs) calculated by membership functions for each evaluation factor are fused through the combination rule of the Dempster-Shafer theory. As a result of the experiment using automatic identification system (AIS) data collected in situations where ships actually encounter each other, the suitability of evaluation was verified. By evaluating the risk of collision in real time in encounter situations between ships, collision accidents caused by human errora can be prevented. This is expected to be used for vessel traffic service systems and collision avoidance systems for autonomous ships.

Privilege and Immunity of Information and Data from Aviation Safety Program in Unites States (미국 항공안전데이터 프로그램의 비공개 특권과 제재 면제에 관한 연구)

  • Moon, Joon-Jo
    • The Korean Journal of Air & Space Law and Policy
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    • v.23 no.2
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    • pp.137-172
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    • 2008
  • The earliest safety data programs, the FDR and CVR, were electronic reporting systems that generate data "automatically." The FDR program, originally instituted in 1958, had no publicly available restrictions for protections against sanctions by the FAA or an airline, although there are agreements and union contracts forbidding the use of FDR data for FAA enforcement actions. This FDR program still has the least formalized protections. With the advent of the CVR program in 1966, the precursor to the current FAR 91.25 was already in place, having been promulgated in 1964. It stated that the FAA would not use CVR data for enforcement actions. In 1982, Congress began restricting the disclosure of the CVR tape and transcripts. Congress added further clarification of the availability of discovery in civil litigation in 1994. Thus, the CVR data have more definitive protections in place than do FDR data. The ASRS was the first non-automatic reporting system; and built into its original design in 1975 was a promise of limited protection from enforcement sanctions. That promise was further codified in an FAR in 1979. As with the CVR, from its inception, the ASRS had some protections built in for the person who might have had a safety problem. However, the program did not (and to this day does not) explicitly deal with issues of use by airlines, litigants, or the public media, although it appears that airlines will either take a non-punitive stance if an ASRS report is filed, or the airline may ignore the fact that it has been filed at all. The FAA worked with several U.S. airlines in the early 1990s on developing ASAP programs, and the FAA issued an Advisory Circular about the program in 1997. From its inception, the ASAP program contained some FAA enforcement protections and company discipline protections, although some protection against litigation disclosure and public disclosure was not added until 2003, when FAA Order 8000.82 was promulgated, placing the program under the protections of FAR 193, which had been added in 2001. The FOQA program, when it was first instituted through a demonstration program in 1995, did not contain protections against sanctions. Now, however, the FAA cannot take enforcement action based on FOQA safety data, and an airline is limited to "corrective action" under the program. Union contracts can exclude FOQA from the realm of disciplinary action, although airline practice may be for airlines to require retraining if there is no contract in place forbidding it. The data is protected against disclosure for litigation and public media purposes by FAA Order 8000.81, issued in 2003, which placed FOQA under the protections of FAR 193. The figure on the next page shows when each program began, and when each statute, regulation, or order became effective for that program.

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Analysis of Annual Variability of Landfast Sea Ice near Jangbogo Antarctic Station Using InSAR Coherence Images (InSAR 긴밀도 영상을 이용한 남극 장보고기지 인근 정착해빙의 연간 변화 분석)

  • Han, Hyangsun;Kim, Yeonchun;Jin, Hyorim;Lee, Hoonyol
    • Korean Journal of Remote Sensing
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    • v.31 no.6
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    • pp.501-512
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    • 2015
  • Landfast sea ice (LFI) in Terra Nova Bay, East Antarctica where the Jangbogo Antarctic Research Station is located, has significant influences on marine ecosystem and the sailing of an icebreaker. Therefore, it is essential to analyze the spatio-temporal variation of the LFI in Terra Nova Bay. In this study, we chose interferometric pairs with the temporal baseline from 1 to 9 days out of a total of 62 COSMO-SkyMed synthetic aperture radar (SAR) images over Terra Nova Bay obtained from December 2010 to January 2012, and then constructed the coherence image of each pair. The LFI showed coherence values higher than 0.3 even in the interferometric SAR (InSAR) pairs of up to 9-days of temporal baseline. This was because the LFI was fixed at coastline and thus showed low temporal phase decorrelation. Based on the characteristics of the coherence on LFI, We defined the areas of LFI that show spatially homogeneous coherence values higher than 0.5. Pack ice (PI) and open water showed low coherence values due to large temporal phase decorreation caused by current and wind. Distinguishing PI from open water in the coherence images was difficult due to their similarly low coherence values. PI was identified in SAR amplitude images by investigating cracks on the ice. The extents of the LFI and PI were estimated from the coherence and SAR amplitude images and their temporal variations were analyzed. The extent of the LFI increased from March to July (maximum extent of $170.7km^2$) and decreased from October. The extent of the PI increased from February to May and decreased from May to July when the LFI increases dramatically. The extent of the LFI and air temperature showed an inverse correlation with a time lag of about 2 months, i.e., the extent of the LFI decreases after 2 months of the increase in the air temperature. Meanwhile the correlation between wind speed and the extent of the LFI was very low. This represents that the extent of LFI in Terra Nova Bay are influenced more by the air temperature than wind speed.

Liability of the Compensation for Damage Caused by the International Passenger's Carrier by Air in Montreal Convention (몬트리올조약에 있어 국제항공여객운송인의 손해배상책임)

  • Kim, Doo-Hwan
    • The Korean Journal of Air & Space Law and Policy
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    • v.18
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    • pp.9-39
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    • 2003
  • The rule of the Warsaw Convention of 1929 are well known and still being all over the world. The Warsaw Convention is undoubtedly the most widely accepted private international air law treaty with some 140 countries. In the international legal system for air transportation, the Warsaw Convention has played a major role for more than half century, and has been revised many times in consideration of the rapid developments of air high technology, changes of social and economic circumstances, need for the protection of passengers. Some amendments became effective, but others are still not effective. As a result, the whole international legal system for air transportation is at past so complicated and tangled. However, the 'Warsaw system' consists of the Warsaw Convention of 1929 the Guadalajara Convention of 1961, a supplementary convention, and the following six protocols: (1) the Hague Protocol of 1955, (2) the Guatemala Protocol of 1971, (3) the Montreal Additional Protocols, No.1, (4) the Montreal Additional Protocol No.2, (5) the Montreal Additional Protocol No.3, and (6) the Montreal Additional Protocol No.4. of 1975. As a fundamental principle of the air carrier's liability in the international convention and protocols, for instance in the Warsaw Convention and the Hague Protocol, the principle of limited liability and a presumed fault system has been adopted. Subsequently, the Montreal Inter-carrier Agreement of 1966, the Guatemala City Protocol, the Montreal Additional Protocol No.3, and the Montreal Additional Protocol No. 4 of 1975 maintained the limited liability, but substituted the presumed liability system by an absolute liability, that is, strict liability system. The Warsaw System, which sets relatively low compensation limits for victims of aircraft accidents and regulates the limited liability for death and injury of air passengers, had become increasingly outdated. Japanese Airlines and Inter-carrier Agreement of International Air Transport Association in 1995 has been adopted the unlimited liability of air carrier in international flight. The IATA Inter-Carrier Agreement, in which airlines in international air transportation agree to waive the limit of damages, was long and hard in coming, but it was remarkable achievement given the political and economic realities of the world. IATA deserves enormous credit for bringing it about. The Warsaw System is controversial and questionable. In order to find rational solution to disputes between nations which adopted differing liability systems in international air transportation, we need to reform the liability of air carriers the 'Warsaw system' and fundamentally, to unify the liability system among the nations. The International Civil Aviation Organization(ICAO) will therefore reinforce its efforts to further promote a legal environment that adequately reflects the public interest and the needs of the parties involved. The ICAO Study Group met in April, 1998, together with the Drafting Committee. The time between the "Special Group on the Modernization and Consolidation of the 'Warsaw system'(SGMW)" and the Diplomatic Conference must be actively utilized to arrange for profound studies of the outstanding issues and for wide international consultations with a view to narrowing the scope of differences and preparing for a global international consensus. From 11 to 28 May 1999 the ICAO Headquarters at Montreal hosted a Diplomatic Conference convened to consider, with a view to adoption, a draft Convention intended to modernize and to integrate replace the instruments of the Warsaw system. The Council of ICAO convened this Conference under the Procedure for the Adoption of International Conventions. Some 525 participants from 121 Contracting States of ICAO attended, one non-contracting State, 11 observer delegations from international organizations, a total of 544 registered participants took part in the historic three-week conference which began on 10 May. The Conference was a success since it adopted a new Convention for the Unification of Certain Rules for International Carriage by Air. The 1999 Montreal Convention, created and signed by representatives of 52 countries at an international conference convened by ICAO at Montreal on May 28, 1999, came into effect on November 4, 2003. Representatives of 30 countries have now formally ratified the Convention under their respective national procedures and ratification of the United States, which was the 30th country to ratify, took place on September 5, 2003. Under Article 53.6 of the Montreal Convention, it enters into force on the 60th day following the deposit of the 30th instrument of ratification or acceptation. The United States' ratification was deposited with ICAO on September 5, 2003. The ICAO have succeeded in modernizing and consolidating a 70-year old system of international instruments of private international law into one legal instrument that will provide, for years to come, an adequate level of compensation for those involved in international aircraft accidents. An international diplomatic conference on air law by ICAO of 1999 succeeded in adopting a new regime for air carrier liability, replacing the Warsaw Convention and five other related legal instruments with a single convention that provided for unlimited liability in relation to passengers. Victims of international air accidents and their families will be better protected and compensated under the new Montreal Convention, which modernizes and consolidates a seventy-five year old system of international instruments of private international law into one legal instrument. A major feature of the new legal instrument is the concept of unlimited liability. Whereas the Warsaw Convention set a limit of 125,000 Gold Francs (approximately US$ 8,300) in case of death or injury to passengers, the Montreal Convention introduces a two-tier system. The first tier includes strict liability up to l00,000 Special Drawing Rights (SDR: approximately US$ 135,000), irrespective of a carrier's fault. The second tier is based on presumption of fault of a carrier and has no limit of liability. The 1999 Montreal Convention also includes the following main elements; 1. In cases of aircraft accidents, air carriers are called upon to provide advance payments, without delay, to assist entitled persons in meeting immediate economic needs; the amount of this initial payment will be subject to national law and will be deductable from the final settlement; 2. Air carriers must submit proof of insurance, thereby ensuring the availability of financial resources in cases of automatic payments or litigation; 3. The legal action for damages resulting from the death or injury of a passenger may be filed in the country where, at the time of the accident, the passenger had his or her principal and permanent residence, subject to certain conditions. The new Montreal Convention of 1999 included the 5th jurisdiction - the place of residence of the claimant. The acceptance of the 5th jurisdiction is a diplomatic victory for the US and it can be realistically expected that claimants' lawyers will use every opportunity to file the claim in the US jurisdiction - it brings advantages in the liberal system of discovery, much wider scope of compensable non-economic damages than anywhere else in the world and the jury system prone to very generous awards. 4. The facilitation in the recovery of damages without the need for lengthy litigation, and simplification and modernization of documentation related to passengers. In developing this new Montreal Convention, we were able to reach a delicate balance between the needs and interests of all partners in international civil aviation, States, the travelling public, air carriers and the transport industry. Unlike the Warsaw Convention, the threshold of l00,000 SDR specified by the Montreal Convention, as well as remaining liability limits in relation to air passengers and delay, are subject to periodic review and may be revised once every five years. The primary aim of unification of private law as well as the new Montreal Convention is not only to remove or to minimize the conflict of laws but also to avoid conflict of jurisdictions. In order to find a rational solution to disputes between nations which have adopted differing liability systems in international air transport, we need fundamentally to reform their countries's domestic air law based on the new Montreal Convention. It is a desirable and necessary for us to ratify rapidly the new Montreal Convention by the contracting states of lCAO including the Republic of Korea. According to the Korean and Japanese ideas, airlines should not only pay compensation to passengers immediately after the accident, but also the so-called 'condolence' money to the next of kin. Condolence money is a gift to help a dead person's spirit in the hereafter : it is given on account of the grief and sorrow suffered by the next of kin, and it has risen considerably over the years. The total amount of the Korean and Japanese claims in the case of death is calculated on the basis of the loss of earned income, funeral expenses and material demage (baggage etc.), plus condolence money. The economic and social change will be occurred continuously after conclusion of the new Montreal Convention. In addition, the real value of life and human right will be enhanced substantially. The amount of compensation for damage caused by aircraft accident has increased in dollar amount as well as in volume. All air carrier's liability should extend to loss of expectation of leisure activities, as well as to damage to property, and mental and physical injuries. When victims are not satisfied with the amount of the compensation for damage caused by aircraft accident for which an airline corporation is liable under the current liability system. I also would like to propose my opinion that it is reasonable and necessary for us to interpret broadly the meaning of the bodily injury on Article 17 of the new Montreal Convention so as to be included the mental injury and condolence. Furthermore, Korea and Japan has not existed the Air Transport Act regulated the civil liability of air carrier such as Air Transport Act (Luftverkehrsgestz) in Germany. It is necessary for us to enact "the Korean Air Transport Contract Act (provisional title)" in order to regulate the civil liability of air carrier including the protection of the victims and injured persons caused by aircraft accident.

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