• Journal of Navigation and Port Research
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• v.35 no.8
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• pp.657-665
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• 2011

This study deals with an integrated problem for deciding sequencing and storage location of export containers together at its receiving operation in the container terminal with a perpendicular layout. The preferred storage location of an export container varies with the priority of the corresponding loading operation and the waiting time of an external truck depends on its storage time. This paper proposes the mixed integer programming model considering the expected arrival time and expected finish time of an external truck and the preferred storage location for its loading operation. And we suggest the heuristic algorithm based on a simulated annealing algorithm for real world adaption. We compare the heuristic algorithm with the optimum model in terms of the computation times and total cost and the performance of the heuristic algorithm is analyzed through a numerical experiment.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.585-591
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• 2014

The primary objective of the current work is to predict speed performance of the medium patrol boat over $F_N=0.5$ employing experimental materials based on the CFD before model tests. In other words, the predicted brake powers according to ship speeds are assessed satisfying the main engine capacity. The subject ships are selected the two different stern hull forms. The flow computation are conducted considering free surface and dynamic trim using a commercial CFD code(STAR-CCM+). The resistances of the bare-hull are obtained from CFD. Wave patterns, pressures and limiting streamlines on the hull and velocity distribution in the propeller plane for the two hull forms are compared using CFD. The effective powers of the object ships are assessed based on CFD. Resistance increase according to the attached appendages and quasi-propulsive efficiency are employed the experimental datas. Speed performance prediction method concerning high speed vessels like a medium patrol boat is developed employing CFD and experimental data.

• Journal of the Korean Society of Marine Environment & Safety
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• v.4 no.2
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• pp.69-83
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• 1998

Sea transportation has long been a vital component of the transport systems of the world. The great majority of imports and exports to and enlarge their national merchant marines. This effort is meant partly to arrest earlier trends of having their trade carried by ships from outside the region and partly to promote regional integration and improve the national balance of payments. However, sea transportation has been exposed to various types of threats on the high seas, in coastal waters and in port areas. Piracy is any robbery or other violent action, for private ends and without authorization by public authority, committed on the seas. Because piracy has been regarded as an offense against the law of nations, the public vessels of any state have been permitted to seize a pirate ship, to bring it into port, to try the crew(regardless of their nationality or domicile), and, if found guilty, to punish them and to confiscate the ship. Piracy has occurred in all stages of maritime history. The increased size of merchant vessels, the improved naval patrolling of most ocean highways, the regular administration of most islands and land areas of the world, and the general recognition by governments of piracy as an international offense resulted in a great decline in piracy in the 19th and 20th centuries. Piracy has, however, occurred in the 20th century, and the practice of hijacking ships has developed into a new form of piracy. The number of incidents of sea piracy against ships reported was 229 in 1997. Since 1991, 1,051 such acts have been reported. The purpose of this research is to examine the origin and development of the piracy to understand the current situation of such violence on the seas. In addition, what should be done by international community will be presented to prevent the piracy in the future.

• Journal of Navigation and Port Research
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• v.27 no.2
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• pp.129-135
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• 2003

This study describes and discusses the marine accidents investigation & inquiry system of Korea, U.K., U.S.A., the Netherlands and Japan. As the results of the comparison of them, the following recommendations are made with respect to improve the system in Korea. (1) The Agency should be independent from the central Government with respect to the budged, personnel management and a agency building. (2) The inspection function and judgment function should be divided into separate Agency. (3) The Agency should has a recommendation right to Government agency according to the results of investigation. (4) The composition of inspectors & judges must be diversified including navigation, marine engineering and naval architecture background. (5) The Agency should have co-operative system with the Marine Police Agency. (6) International affairs division should be included in the Agency to promote international relations.

• Journal of Navigation and Port Research
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• v.34 no.3
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• pp.161-166
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• 2010

The bandwidth of detecting radars used for military purpose is increasingly broadened, and recently, the frequency band of the detecting radars is expanding to millimeterwave bands of the millimeterwave bands of 35 GHz and 94 GHz. Since, especially, it is essential and important to fabricate and develop EM wave absorber with the absorption ability more than 10 dB in 94 GHz band, the EM wave absorber was manufactured based on the design method by FDTD simulation. As a result, the developed EM wave absorber with the composition ratio of Binder(CPE with additional materials) : Carbon = 70 : 30 wt.% has the thickness of 0.7 mm and the absorption ability more than 14 dB in the frequency range of 94 GHz.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.241-246
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• 2006

The paper presents the preparations work and experiences gained from realtime GPS car monitoring during the European Rally Championships organized on 10-12 June 2005 in Poland. The developed system is based on GPS and GSM/GPRS technology. Distribution and teletransmission of data are possible using different GSM operators in Poland, which makes the system fully independent. The system's server collects data from rally cars, processing and send data through VPN connections to the SQL server located in main control room. Data can be collected in real time via Internet or GPRS. Some information on GSM/GPRS range during rally championships are also presented in the paper. The study covered many trials and tests of different software and various configurations of the GPRS modems before finally the system started to work. Information coming from 10 Rally Cars were collected to the SQL Server continuously in one second interval. In real time mode these all data were displayed simultaneously in the rally main control room and in the rally press conference room. Paper describes also adopted emergency procedures and remote reconfiguration of GPS/GPRS boxes inside rally cars made during championships. Some problems and method of practical solutions are presented to avoid active jamming dangerous for a driver and his pilot, having system of communication intercoms jammed by teletransmission of GPRS 900/1800 MHz. In cooperation with rally teams special GPS/GPRS safety boxes were designed and made. Monitoring of all 7 rally stages with GPS receivers and method of calibrations of the maps were presented. GSM signal coverage was also checked in all stages. All data transmitted from rally cars were recorded in the computer. Some of our GPS cars had accidents and dispite them information were continuously sent to server. There is possibility to show in post mission mode the position of chosen cars in our rally application. Some information of best rally cars are presented also in the paper.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.333-335
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• 2006

Position of surface objects can be fixed in many ways. The most popular radionavigational systems, including satellite systems, make possible obtaining nearly continuous and very precise ship's position. However, under the water application of radionavigational systems is impossible. Underwater navigation requires other tools and solutions then these encountered in surface and air navigation. In underwater environment vehicles and submarines, operate that have to possess alternative navigational systems. Underwater vehicles, in order to perform their tasks require accurate information about their own, current position. At present, they are equipped with inertial navigational systems (INS). Accuracy of INS is very high but in relatively short periods. Position error is directly proportional to time of working of the system. The basic feature of INS is its autonomy and passivity. This characteristic mainly decides that INS is broadly used on submarines and other underwater vehicles. However, due to previously mentioned shortcoming i.e. gradually increasing position error, periodical calibration of the system is necessary. The simplest calibration method is surface or nearly surface application of GPS system. Another solution, which does not require interruption of performed task and emergence on the surface, is application of comparative navigation technique. Information about surrounding environment of the ship, obtained e.g. by means sonic depth finder or board sonar, and comparing it with accessible pattern can be used in order to fix ship's position. The article presents a structure and a description of working of underwater vehicle navigation system simulator. The simulator works on the basis of comparative navigation methods which exploit in turn digital images of echograms and sonograms. The additional option of the simulator is ability to robust estimation of measurements. One can do it in order to increase accuracy of position fixed with comparative navigation methods application. The simulator can be a basis to build future underwater navigation system.

• Journal of Navigation and Port Research
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• v.35 no.5
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• pp.381-385
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• 2011

In this paper, an economic feasibility study of wind-diesel hybrid power systems for an island in the Yellow Sea, where the maximum power generation is about 500kW, was performed. For the study, annual electric load variation and wind resource data of the island were collected and analyzed. HOMER program - a typical hybrid optimization model for electric renewables including wind resource, developed by the National Renewable Energy Laboratory - was used. Wind speed and diesel price were picked out as variables for the sensitivity analysis in order to find the economic accountability for the wind-diesel hybrid power system. As the result, even though it is not feasible economically under the present condition, if mean wind speed is over 3 m/sec. or diesel price goes up to 2.4 $ per liter, the wind-diesel hybrid power system for the island becomes a prospective candidate.

• Journal of Navigation and Port Research
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• v.31 no.10
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• pp.845-852
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• 2007

An OWC-type Wave Energy Conversion passes through 3 steps energy conversion process. This paper deal with the impulse turbine with staggered blade to improved performance by numerical analysis using commercial CFD code, FLUENT Maximum value of axial airflow velocity during exhalation is higher than that during inhalation This paper deal with special-type of Impulse Turbine so-called "Staggered Blade" for more efficiency to making air flow direct to on pressure side. Also, this paper has proposed special-type turbine with self-pitched blade more efficient.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.10a
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• pp.40-41
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• 2009

In general, ships are towed to keep the safe operations in harbor or channel by tug boats. Due to increase in ocean traffic, many accidents are happened in harbor or channel in these days. Therefore it is necessary to predict manoeuvrability of tug-barge system, and to assure the safety of that system. Turg-barge system is composed of tug boat, barge, and towing cable, connecting both ships. Manoeuvring equations of tug-barge system are suggested, and the scopes of model tests are discussed to establish the mathematical models for tug boats in this paper.