• Journal of Navigation and Port Research
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• v.32 no.2
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• pp.127-132
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• 2008

The safety degree of navigation for collision avoidance is closely related with the combination between mariner's behavior and navigational environment. The condition of navigational environment is mainly decided by navigable waters, ship traffic, rule of road, sea state, weather and so on. Especially, the condition of navigable waters and ship traffic in navigational environment are ones of the important factors to attain safe navigation when mariners are underway and crossing, head on or overtaking situation. Thus this paper is to analyze the characteristics of mariner's behavior for collision avoidance caused by ship traffic and navigable waters by analyzing the contents of questionnaire and the results of international collaborative research. As a result, it can be concluded that the density of ship traffic and the area of navigable waters affect mariner's ship handling for collision avoidance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.10
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• pp.2236-2245
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• 1997

The DBS system is being highlighted as actual area for the information societics. Specially, the DBS have been proposed very useful system to access the broading service in more widely sea. But the antenna tracking system for maritime DBS receiving is requried complicated control system because of the those complex motion represented pitching, rolling and yowing etc. Our resesrch target is a development of tracking system to the KOREASEA(MUGUNGWHA-1,2) for the applicated small size shipping. So our development focus was concentrated the two development direction. The first focus was represented low-cost system for popularization of small-size shipping around sea of the Korea peninsula. The second focus was an adaptive possibilities with domestic eqdupiment which was developed satellite receiving for KOREASAT. The anntenna mount is designed a compact size and easy operation use to the Az/El 2-axis type which is operated by step motor. And this mount type is very useful on a ship in the near sea of Korea peninsula. Basic tracking method is used th step-tracking algorithm, and the ship's moving compensation is adapted to the closed loop control method by ship's moving detection of gyro sensor. Control part is consists of converter, countertime, VCO, micro-computer and it's software. Testing the operation by the ship's moving simulator, and algorithm is designed tracking and moving compensation by receiving state.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.4
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• pp.289-295
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• 2005

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 manoeuvrability of own ship. The actual manoeuvering characteristics of ship can be adequately judged from the results of typical ship trials manoeuvres. Author carried out sea trials based full scale for turning test, zig-zag test, spiral tests and crash-stop test at actual sea going condition. The turning circle manoeuvres were performed on starboard and port sides with $35^{\circ}$ rudder angle at the service speed, and Zig-zag procedures were performed on both sides with $10^{\circ}$ and $20^{\circ}$ rudder angle respectively. Spiral tests were carried out on the both sides and crash stop test was also carried out. The results from tests could be compared directly with the standards of manoeuverability of IMO and consequently the manoeuvring qualities of the ship is fully satisfied with its.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.2
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• pp.107-113
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• 2014

The icebreaking research vessel, ARAON had her second ice trial in the Arctic Sea from 16th July to 12th August 2010. During the voyage, the local ice loads acting on the bow of port side were measured from 14 strain gauges. The measurements were also carried out in ice waters with various ice concentration ratio as well as the icebreaking performance tests. In this study, the ice loads measured during the 'general' operation in ice waters were analyzed. As a first step, the relationship between the location of strain gauges and the ice loads were investigated, and then the possibility for observation of higher ice loads was estimated based on the probability density function. The relationship between the ship speed and the ice load was also investigated. 718 peak stresses data higher than 20 MPa obtained from strain gauges array attached in longitudinally and vertically was analyzed. In general, the ice load increases as the ship speed increases in the low ship speed range, and ice load decreases as the ship speed is greater than a certain speed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.560-564
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• 2009

This paper introduces measurement and evaluation of vibration of the ship propulsion machinery (ISO 20283-4). ISO 20283-2 for measurement of structural vibration on ships was finalized last year and ISO 20283-4 was drafted and reviewed by particulate ISO members now. As the importance and core field in ISO 20283-4, the torsional vibration of propulsion system for sea going vessels should be analysed in design stage and it should be confirmed by the its measurement during the sea trial. Criteria for evaluation of torsional loadings are defined by IACS (International Association of Classification Societies) UR M68. In this paper, the author introduced the important and controversial matters during the review of ISO 20283-4.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.295-301
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• 2018

This study compares optimization algorithms for efficient estimations of ship's hydrodynamic coefficients. Two constrained algorithms, the interior point and the sequential quadratic programming, are compared for the estimation. Mathematical optimization is designed to get optimal hydrodynamic coefficients for modelling a ship, and benchmark data are collected from sea trials of a training ship. A calibration for environmental influence and a sensitivity analysis for efficiency are carried out prior to implementing the optimization. The optimization is composed of three steps considering correlation between coefficients and manoeuvre characteristics. Manoeuvre characteristics of simulation results for both sets of optimized coefficients are close to each other, and they are also fit to the benchmark data. However, this similarity interferes with the comparison, and it is supposed that optimization conditions, such as designed variables and constraints, are not sufficient to compare them strictly. An enhanced optimization with additional sea trial measurement data should be carried out in future studies.

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.31-31
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• 2018

• Journal of the Korean Institute of Navigation
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• v.24 no.3
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• pp.133-140
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• 2000

The paper deals with the implementation of prototype Ship Simulator system (VRSS) by Virtual Reality techniques with Head Mounted Display (HMD) device. The prototype VRSS was consists of PC-based human sensors, object oriented operating system. In addition, two kinds of databases arranged from Head Related Transfer Functions and 3D object models were used to create 3D sea sound, and to construct virtual world, respectively. Using the prototype system, we carried out some simulation tests for the overtaking situation to prevent collisions at sea, and discussed on the usability of the system. As results from simulations, the prototype VRSS can provide multisensory and interactive display environment. The results gave rise to the user interaction with 3D objects that give realistic reproduction of navigational environments under a given scenario. Thus, we found that the prototype VRSS should be one of the next-generation ship simulation system.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.3
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• pp.421-429
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• 2008

Various kinds of ship are operated to transport cargo or passengers at sea in the world. Most of the important auxiliary machineries installed in those ships are fluid machineries such as pumps, compressors, and fans. A large percentage of fluid machinery is pumps which are classified turbo and positive displacement pumps. This paper analyzes only positive displacement pumps. This thesis has two aims: (a) to analyze the present status of pumps installed in merchant and training ships and (b) to find the correlation among sea going pump kW, port pump kW, total pump kW, GE kW, ME MCR, number of pumps, ME kgf, pump kgf. Based on ship's type, this paper seeks to find special characteristics as a result of analyzing head, flow rate, and kW. Moreover this paper analyzes and compares number of pumps, pump kW/ME MCR, pump kW/GE kW under the conditions of seagoing and berthing according to ship's type.

• 한국기계연구소 소보
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• s.10
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• pp.35-48
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• 1983

When the hydrodynamic coefficients of the ship maneuvering equation are estimated by captive model test, it is difficult to take account of the scale effect between model and full scale ship. This scale effect problem can be overcome by processing the sea trial data with system identification. Extended Kalman filter is used as a system identification technique for the modification of the simulation equation as well as the estimation of hydrodynamic coefficients. The phenomena of simultaneous drifting of linear coefficients occur. It is confirmed that two coefficients in each pair-($Y_v$', $Y_r$' -m' u'), ($N_v$', $N_r$' )-are simultaneously drifting and all 4 coefficients are simultaneously drifting together. Particularly simultaneous drifting of 2 coefficients in each pair is more significant. It is also shown that the simultaneous drifting of 4 coefficients can be reduced by choosing the input data which have the random v'/r' curve and 4 coefficients are estimated within 2-4% error, which may be noise level. So, it is recommended to operate the rudder randomly in sea trial or model test for the application of system identification technique.