• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.250-257
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• 1993

The Global Positioning System(GPS) is a worldwide radio navigation system based on satellite technology. Signal availability and accuracy of GPS are subject to change due to an incomplete constellation and operational test activities. In order to analyze the signal availability and accuracy of GPS, we made an experiment on this system in Kunsan during April 6, 7, 9, 10, 1992. The results obtained are summarized as follows: 1. It was possible to avail the GPS system almost 24 hours per day, but sometimes it was impossible to obtain the GPS signal 2 or 3 times per day and its total time was at the most an hour. 2. By using satellite almanac, we also could calculate PDOP(HDOP) and forecast signal availability. And the mean positional error was $37.9{\sim}73.6m$ and standard deviation was $37.4{\sim}133.1m$. The positional error almost coincided with PDOP(HDOP). 3. The mean positional error of 3D was less than that of 2D. And the altitude error in 3D was about $56{\sim}74m$ and its standard deviation was about $65{\sim}93m$.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.54-63
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• 2022

The Marine Accident Investigation and Tribunal System is intended to provide a credible solution to prevent the recurrence of similar accidents. When a marine accident occurs, the Korea Maritime Safety Tribunal seeks to find its root causes through an analysis of what provoked the accident. It also contributes to the development of safety policies or practices by making a decision based on the findings. However, if the decision presented as the root cause of a marine accident is ambiguous or unclear, it may be difficult to achieve its intended goal. Hence, if we read some of the decisions of the Maritime Safety Tribunal, it is selective to directly apply the cause of an accident as a source of the measures that can prevent its recurrence. A typical example of this is the expression: "when a seafarer neglects ordinary practice of seaman." The term "ordinary practice of seaman" has been criticized for being used in some decisions like a master key where it is not easy to determine which specific rules or regulations were violated or blame the involved seafarers. Such term is present in Article 2 of the International Regulations for Preventing Collisions at Sea 1972. For the proper use of the term, this paper seeks to compare and establish the concepts of "ordinary practice of seaman" and the duty of care by providing a systematic interpretation of the original text. In addition, the duty of care was reviewed from the perspective of administrative, civil, and criminal laws. Furthermore, relevant legal precedents were reviewed and presented in the study. Accordingly, it is expected that the term "ordinary practice of seaman" would be properly used in decisions that contribute to the prevention of the recurrence of similar marine accidents.

• Journal of Popular Narrative
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• v.25 no.1
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• pp.165-191
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• 2019

The purpose of this article is to elucidate why the motif of time travel is repeated in the science fiction narrative by examining the functions of this motif in the SF movie series of Star Trek in its narrative and non-narrative aspects. Star Trek IV: The Voyage Home (1986) aims to attract the audience's interest in the story through the use of plausible time travel in the form of the slingshot effect which causes the spacecraft to fly at very fast speeds around an astronomical object. The movie also touches upon the predestination paradox that arises from a change of history in which it describes a formula of transparent aluminum that did not exist at the time. The film also serves as an evocation of the ideology of ecology by including humpback whales in the central narrative and responding to the real issue of the whale protection movement of the times. Star Track VIII: First Contact (1996) intends to interest the audience in the narrative with the warp drive, a virtual device that enables travel at speeds faster than that of light and a signature visual of Star Trek, at the time of its birth through time travel. The film emphasizes the continuation of peaceful efforts by warning the destruction of humanity that nuclear war can bring. It tackles with the view of pacifism and idealism by stressing the importance of cooperation between countries in the real world by making the audience anticipate the creation of the United Federation of Planets through encounters with the extraterrestrial. Star Trek: The Beginning (2009) improves interest through the idea of time travel to the past, this time using a black hole and the parallel universe created thereby. The parallel universe functions as a reboot, allowing a new story to be created on an alternate timeline while maintaining the original storyline. In addition, this film repeats the themes pacifism and idealism shown in the 1996 film through the confrontation between Spock (and the Starfleet) and Nero, the destruction of the Vulcan and the Romulus, and the cooperation of humans and Vulcans. Eventually, time travel in three Star Trek films has the function of maximizing the audience's interest in the story and allowing it to develop freely as a narrative tool. It also functions as an ideal solution for commenting on current problems in the non-narrative aspect. The significance of this paper is to stress the possibility that the motif of time travel in SF narrative will evolve as it continues to repeat in different forms as mentioned above.