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        검색결과 169

        41.
        2018.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, a motion control problem for the vessels towed by tugboats or towing ships on the sea is considered. The towed vessel looks like the barge ship, which is used for many purposes. In these vessels, basically, the power propulsion system is not installed but just towed by a towing vessel such as tugboats with ropes and wires. It means that the motions of towed vessel are basically dependent on the tracking route of towing boat. Therefore, in some cases, undesirable and unpredictable motions may be made by environmental factors such as wave, wind attack and so on. As a result, a collision accident with others may occur during maneuvering situation. Based on these facts, the authors try to encourage the steering performance of the towed vessel by using controllable rudders without any propulsion system. In this study, especially, a controllable vessel with three rudders is considered, and a mathematical model is induced for the future study. The model is described as surge, sway motion and inertia moment by following the general representation method for the surface ship.
        4,000원
        44.
        2018.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        International Maritime Organization (IMO) has established standards for ship manoeuvrability and applied these standards for vessels over 100 meters in length that built since 2004 (IMO, resolution MSC.137[76]). These standards are no exception to fishing vessels. In this study we carried out a manoeuvring simulation of the new model ship (Stern trawler) of fisheries training ship of Pukyong National University based on Kijima's empirical formula. The formula takes into account of the effect of stern shape or does not take into account of the effect of stern shape. Also we checked whether the simulation results of turning motion of model ship meet IMO manoeuvrability criteria and then compared trajectories between the simulation results of model ship and the results of real sea trial test of the existing ship. In conclusion, Kijima's empirical formulas can estimate the manoeuvrability of fishing vessels at design stage approximately, it needs more parameters of fishing vessel own in case of expressing the manoeuvrability of fishing vessel accurately.
        4,000원
        47.
        2018.05 구독 인증기관·개인회원 무료
        Aircraft landing is a complex and challenging flight phase in which pilots are required to allocate attention efficiently to the surrounding environment. A comprehensive understanding of pilot situation awareness (SA) is needed for successful landing. This study was to predict pilot SA during landing using eye tracking data. The experiments were carried out with 5 repetitive simulated landings for four expert and four novice pilots using eye tracking equipment. Three eye tracking features (visit frequency, dwell time ratio, scan path entropy) were developed for reflecting three level of SA model (perception, comprehension, projection). Prediction of SA was performed by developing multiple regression model. Visit frequency of expert pilots was 138%, 47%, 85%, 67%, 117%, and 91% higher than novice pilots in RPM, VVI, altimeter, heading, airspeed, and attitude areas of interest (AOIs) respectively; while 50% and 33% lower in runway and outside AOIs respectively. Dwell time ratio of expert pilots was 38% and 42% higher than novice pilots in runway and outside AOIs respectively; while 62%, 62%, and 65% lower in altimeter, airspeed, and attitude AOIs respectively. Scan path entropy of expert pilots was 33% higher than novice pilots in outside AOI; while 29% lower in attitude AOI. Coefficient of determination for the prediction model for SA was 80.6%. The results of this study can be used as objective data of strategy establishment or training feedback for novice pilots.
        48.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        종합 안전관리체계인 e-navigation을 준비하기 위해 선박의 의도된 경로를 선박 대 선박, 그리고 선박 대 육상 간에 공유하는 경로교환에 대한 연구가 활발히 진행 중이다. 하지만 경로교환을 위한 기술적인 측면에서의 연구·개발은 진행되고 있으나, 그 효과나 문제점 등 도입 필요성에 대한 연구는 부족한 실정이다. 본 연구는 선박조종 시뮬레이션을 통해 경로교환이 항해 안전에 미치는 영향을 정량적으로 분석하고, 시뮬레이션 수행자들의 주관적인 평가를 종합하여 경로교환의 효과를 검증하였다. 선박 간 경로교환을 할 경우 최초 충돌회피 시점은 평균 3.43분 더 빨라졌으며, 충돌회피 방향은 60%가 변경되었다. 또한 타선 A와의 최근접점은 31% 더 가까워지고, 평균 타 사용지수는 57% 줄어들었다. 그리고 설문 응답자의 95%는 경로교환이 충돌회피 의사결정에 영향, 85%는 안전운항에 긍정적인 영향, 90%는 사고예방 효과, 70%는 항해사의 심리적 부담 경감, 70%는 경로교환을 실무에 도입해야한다고 답하였다.
        4,000원
        55.
        2017.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is intended to provide navigator with specific information necessary to assist in the avoidance of collision and in operation of ships to evaluate the maneuverability of research vessel Jera. Authors carried out full-scale sea trials for turning test, zig-zag test, and spiral test at actual sea-going condition, which were performed on starboard and port sides with 10-20 rudder angle at service speed of 10 knots. The turning circle was much different at both of the turning of port and starboard which was longer at the starboard than at the port. In the zig-zag test results, the port and starboard was 10˚ the first and second overshoot angles were 6.0˚ , 5.8˚ and 6.3˚ , 7.1˚ respectively and the first overshoot angles were 16.4˚ , 17.6˚ when using 20˚ . Her maneuverability index T and K can be easily determined by using an analogue computer with the data obtained from the zig-zag tests where K is a constant representing the turning ability and T is a constant representing her quick response. In the zig-zag tests under 10˚ or 20˚ at rudder angle, the value K is 0.149. 0.123 sec- and T is 11.853 and 6.193 sec and angular velocity is 0.937˚ /sec and 1.636˚ /sec. In the spiral test, the loop width was unstable at +0.51˚ and -1.19˚ around the midship of rudder, but the tangent line at 0˚ was close to vertical. From the sea trial results, we found that she did comply with the present criterion in the standards of maneuverability of IMO.
        4,000원
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