• Journal of the Korean Society of Marine Environment & Safety
• /
• v.3 no.1
• /
• pp.15-31
• /
• 1997

This work aims at examining the navigational safety of the entrance channels of Masan harbour and suggesting the way to improve ships' navigational safety through the channels. It has been found, from the on-scene investigation of the navigational safety at Masan, that the depth of the Budo-Sudo channel is not deep enough to cater for the largest vessel visiting the harbour, and that the No.2 navigational channel is not wide enough for the vessel. An additional new waterway, therefore, has been recommended to be established in the south of the Budo-Sudo channel so that the deep draft vessel can detour. The No.2 navigational channel has been recommended to be widen. The width of the channel was suggested to be 280 meters. A waterway design simulation methodology has been applied to examine the safety of the newly suggested channels. New channels have been proved to be safe from the experiment.

• Journal of Korean Society of Transportation
• /
• v.8 no.1
• /
• pp.5-15
• /
• 1990

As a result of the lack of methodology for the determination of navigational channel capacity and the consequence lack of effective management of traffic, navigational channels are often grossly underutilized or highly congested. The traditional rule of first-come-first-served admission of vessels to channels is not efficient as it assumes equal time intervals between entrance of consecutive vessels. A new vessel traffic management system is developed in this research and methodologies to measure the improvement in the channel capacity are developed. Methodology to measure the channel performances for three queue disciplines are developed. The effects of changes in major factors on the channel capacity model such as channel length, fleet mix and arrival rate, as well as changes in strategy are analyzed. Under given channel conditions, best strategy are recommended. Also, a method for effective stochastic channel capacity simulation was developed. The results of analysis and as ertions are compared with the results of simulation runs to prove their applicability.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.1 no.1
• /
• pp.9-25
• /
• 1995

Although the studies carried out in recent years have provied much new information about channel widths and alignment, they are not consistent in their results. In addition, as a result of variations in local condition and type of traffic accommodated, the dimensions of the channel widths vary over a wide range. Therefore, the recommendation made by the maritime engineering organizations over the world, do not offer detailed and decisive optimal design criteria and are all different. It, therefore, was attempted in this paper to draw a decisive guideline on the optimal widths and alignment of the navigational channels, which can be utilized by the port designers at the stage of the planning. The guideline was drawn through the comparison and analysis of the existing guidelines of the U.S.A, Japan and PIANC and simulation experiment. The simulation experiment was carried out using the "Off Line Port and Waterway Design Simulator" to find the optimal dimensions of the widths of the navigational channels. 90 different simulation runs were conducted at the 3 different secenario channels. New guidelines, the result of the study, is expected to be used usefully by the Korean port designers when designing the rapodly developing ports in Korea. in Korea.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.2 no.1
• /
• pp.11-33
• /
• 1996

This work aims at examining the navigational safety of the entrance channel of Inchon harbour and suggesting the way to improve ship's navigation of the navigational safety at Inchon, that small ships such as fishing boats and barges coming out of the harbour through the East Channel cause major threat to the inbound large ships using the channel. An additional new waterway, therefore, has been recommended to be established in the middle of the East and West Channels so that the outbound small ships can use it. A waterway design simulation methodology has been applied to examin the sagety of the newly suggested channel. Minor chansge has been made to the original design after the simulation experiment, and the corrected final design of the waterway has been suggested to be implemented as soon as possible.

• Journal of Advanced Navigation Technology
• /
• v.23 no.6
• /
• pp.570-576
• /
• 2019

The configuration of dispersion-managed optical link with optical phase conjugator, which is placed at the non-midway of total transmission length, is proposed for implementing of the flexible optical network. The optical phase conjugator is located between the former half transmission section and the latter half transmission section, which are consisted of 6 fiber spans and 14 fiber spans respectively, and the averaged RDPS of each half transmission section are inconsistence. And, the artificial distribution of each fiber span's RDPS, which are gradually increased/decreased as the span numbers are increased, is adopted to compensate for the distorted wavelength division multiplexed channels. From the simulation results, it is confirmed that the compensation in dispersion-managed link configured by a special distribution pattern among 16 proposed patterns, in which the RDPS of each fiber spans are gradually decreased/increased in the former/latter half section with the small deviation, is suitable to compensate for the distorted wavelength division multiplexed channels.

• Journal of Advanced Navigation Technology
• /
• v.24 no.5
• /
• pp.408-414
• /
• 2020

The method of overcoming the limitation of optical phase conjugator applied into optical long-haul link for transmitting high capacity wavelength division multiplexed (WDM) channels was investigated. The configuration of optical link was based on dispersion-managed link, in which dispersion compensating fiber inserted into each fiber span with single mode fiber, and optical phase conjugator was added into suitable location of link. The maximum number of fiber spans as a function of the launch power of WDM channels in optical link with optical phase conjugator placed at the proposed location was induced and compared for analyzing the compensation performance of the distorted WDM channels. It was confirmed that the more optical phase conjugator depart from the midway of total transmission length, the less the distorted WDM channels was compensated, however, it was also confirmed that the degradation of compensation can be overcome by the suitable value of residual dispersion per span and by the reasonable choice of fiber span controlling total dispersion accumulated in overall transmission link.

• Journal of Advanced Navigation Technology
• /
• v.25 no.4
• /
• pp.286-292
• /
• 2021

Dispersion maps of antipodal symmetric type for improvement of compensation effect in dispersion managed link combined with optical phase conjugation, which can compensate for the distorted wavelength division multiplexed (WDM) signals due to chromatic dispersion and nonlinear Kerr effects of single-mode fiber, were proposed. It was confirmed that the proposed all of antipodal symmetric dispersion maps was more effective to compensate for the distorted WDM channels than the conventional link of uniform type dispersion map. Especially, dispersion maps formed like the inversion of alphabet S were more advantageous as the distorted WDM channels were compensated than dispersion maps formed like alphabet S. It was expected that the variety of optical network topology was more expanded by applying the proposed antipodal symmetric dispersion maps into transmission link.

• Journal of Navigation and Port Research
• /
• v.39 no.6
• /
• pp.451-456
• /
• 2015

This research examines the use of Cross Bearing in the Republic of Korea Navy. Specifically, this study focuses on the degrees of errors caused by the order of measuring targets and suggests a new method to determine Advice Course. It then reviews the appropriateness of the contents of Location Report that is regularly to the duty officer during a voyage in a narrow channel. Whenever a naval vessel passes through a narrow channel, many number of sailors are assigned to diverse positions in order to enhance navigational safety. Even though it is possible to easily recognize the location of a ship with helps of various kinds of navigational equipments using state-of-the-art technology, there are still several situations where sailors' efforts are indispensible for calculating the position of their ship : when the ship is damaged during an engagement with enemies and when the enemies interfere (GPS) signals. In addition, the particularity of naval vessels in which many number of crew members can be assigned to various positions supports for the suitability of the use of Cross Bearing in the Navy. This study will contribute to navigational safety of the ROK Navy and fostering junior naval officers' seamanship.

• Journal of Advanced Navigation Technology
• /
• v.22 no.3
• /
• pp.240-245
• /
• 2018

A flexible dispersion-managed link configuration is proposed by using single-mode fibers (SMFs) and dispersion-compensating fibers (DCFs) with irregular dispersion coefficients and lengths over all fiber spans for compensating of WDM channels distortion due to the group velocity dispersion and nonlinear effects of optical fibers. The flexibility of link is enabled by artificially distributing of these fibers based on the dispersion coefficients of DCFs in each half transmission section. The simultaneous ascending and descending (AD) distribution of the DCF's coefficients before and after the optical phase conjugator, respectively, best compensates the distorted wavelength division multiplexed signals in the optical link. Therefore, to improve the compensation effect of the distorted WDM channels, AD distribution is needed to choice regardless of fiber lengths and the residual dispersion per span and fiber's dispersion coefficients.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2006.10a
• /
• pp.230-239
• /
• 2006

The depth, width and alignment of fairway that are main port water facilities should be designed considering the various elements including particulars of design ships, weather and sea conditions around fairway and method of ship-handling. However not only the existing Japanese design standard for fairway and also those of other countries do not take into consideration of such kind of elements and no design standard is made by quantitative analysis. In this circumstance the new design standard (Approach Channels, A Guide for Design) depending on classified various elements and quantitative analysis was proposed in 1997 by PIANC and IAPH. But it was proved that calculated values according to this standard were unfounded and had some problems to output the discontinuous value by small difference of calculation condition because the each value fur each element was simply added. And also it is hard to apply this standard to the design of port water facilities in Japan because this [A Guide for Design] is the design standard for long channels in European port. The proposal of more reasonable Japanese standard will be expected by applying the study result of naval architecture and navigation and by the cooperation of ship operators to use fairway, naval architects to built ships and civil engineers to dredge fairway. The concept of a fairway in 'Design standard fur fairway in next generation' is defined as passage for approach channel) and traffic lane designated by light buoys as navigable water for safe navigation. In 'Design standard for fairway in next generation' depth, width and alignment are picked up among many design elements of a fairway. Design method for those elements is shown based on design ships and navigational environments. This standard shows the method of design for each dimension depending on characteristic on design ship and weather and sea condition. On the other hand, in case of existing fairway, it is possible to decide the size of ship and navigation criteria by opposite analysis.