• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2022.06a
• /
• pp.339-343
• /
• 2022

In this study, a method for simplifying the structure of the VDES RF receiver, and the gain control method of the receiver to comply with the international standard in this structure was described. The input level of the wanted signal and unwanted signal to the receiver was defined, and when the two signals were input, the saturation state at the ADC was checked at the receiver output. As a result of the simulation by the circuit simulator, it was satisfied that the output power of the receiver was in the SFDR region of ADC with respect to the adjacent channel interference ratio, intermodulation, and blocking level. Through this study, it was found that the structure of th proposed RF receiver conforms to the international standard.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.6
• /
• pp.658-665
• /
• 2019

Among the renewable energy resources, wind power is growing rapidly in terms of technological development and market share. Recently, onshore wind farm have been affected by limitations of terrestrial space and environmental problems. Consequently, installation sites have been moved to the sea, and the development of floating offshore wind farms that are installed at deep waters with more abundant wind conditions is actively underway. In the context of maritime traffic, the optimal site of offshore wind farms is required to minimize the interference between ships and wind turbines and to reduce the probability of accidents. In this study, genetic algorithm based AIS(Automatic Indentification System) data composed of genes and chromosomes has been used. The optimal site of floating offshore wind farm was selected by using 80 genes and by evaluating the fitness of genetic algorithm. Further, the final site was selected by aggregating the seasonal optimal site. During analysis, 11 optimal site were found, and it was verified that the final site selected usng the genetic algorithm was viable from the perspective of maritime traffic.

• Journal of the Society of Naval Architects of Korea
• /
• v.54 no.6
• /
• pp.501-514
• /
• 2017

In the previous research, a study was carried out to estimate the actual performance such as the propeller Revolution Per Minute (RPM) and engine power of a Liquefied Natural Gas Carrier (LNGC) using the full-scale measurement data. After the predicted RPM and engine power were verified by comparing those with the measured values, the suggested method was regarded to be acceptable. However, there was a limitation to apply the method on the prediction of the RPM and engine power of a ship. Since the information of route, speed, and environmental conditions required for estimating the RPM and engine power is generally regarded as the intellectual property of a shipping company, it is difficult to secure the information on a shipyard. In this paper, the RPM and engine power of the 151K LNGC was estimated using the combination of Automatic Identification System (AIS) and European Centre for Medium-Range Weather Forecasts (ECMWF) database in order to replace the full-scale measurement. The simulation approach, which was suggested in the previous research, was identically applied to the prediction of RPM and engine power. After the results based on the AIS and ECMWF database were compared with those obtained from the full-scale measurement data, the feasibility was briefly reviewed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.177-180
• /
• 2005

AIS needs high efficiency and safety in terms of operational management and, in the aspect of service range, it is time to minimize shadow regions through propagation evaluation of AIS transmitter. Thus this study analyzes shadow regions and the scope of propagation of waves from stations through the electric wave environment of AIS. First, this study examines the characteristics of AIS wave and draws up methods to analyze the scope of propagation of waves according to the characteristics. Second, this study finds out service regions and shadow regions of the 22 stations across the nation by analyzing the actual data based on climate and topography, Lastly, this study summarizes the results of wave conductivity evaluation and conductivity problems and proposes improvement measures.

• Journal of Navigation and Port Research
• /
• v.34 no.5
• /
• pp.337-342
• /
• 2010

As AIS AtoN has worked an essential role for aids to navigation, the World-wide IALA-Net has announced plans to build the system. Systematic beacon network may offer opportunities to make an infrastructure for information service and upgrade AtoN service performance. This paper proposes Aids to Navigation information service network for e-NAV. Network based on AIS is consist of AIS AtoN channels as Real, Synthetic or Virtual AIS AtoN. And inner network is consist of Wireless networks as AIS, WCDMA, WIFI, WIBRO, USN or VSAT. Introducing of various network systems can lead to combine and design aomong land, beacon and service network infrastructures.

• Journal of Navigation and Port Research
• /
• v.31 no.10
• /
• pp.807-812
• /
• 2007

With the advent of Electronic Chart Display and Information Systems(ECDIS) and Automatic Identification Systems (AIS) as the principal navigation equipment of E-navigation strategy, mariners will begin to practice "e-navigation" and increasingly rely upon these systems to navigate safely and efficiently. However, these electronic systems require "e-inputs" in order to function. At present, the choices for e-input are limited, and they are installation dependent. This means that the mariner must be suitably equipped in order to use an alternative e-input. If the primary e-input is lost, and the vessel is not equipped to make use of suitable alternative e-inputs, then continued operations will have to be done the "old fashioned way" using conventional navigation The final objective is a recommendation of dual harbor positioning system on the most appropriate mix of positioning systems to satisfy the marine needs for radionavigation, positioning services.

• Journal of Navigation and Port Research
• /
• v.37 no.4
• /
• pp.391-400
• /
• 2013

Each country has recently established and operated so called Aids to Navigation(AtoN) AIS system collecting and transferring information on the sea state and AtoN's position. Korea has also decided to introduce the system and been establishing it. And it has already installed and operated this system in Incheon and Daesan. For the purpose of giving the national standards of AtoN AIS, this paper is to investigate the present states of AtoN AIS systems in the above two area and to suggest the improvement to the operation of AtoN AIS system. To make it, the paper deals with the international regulations of related AtoN AIS and the cases of foreign's AtoN AIS system installed and also investigates the operation states of the system, in five modules such as system management, system composition, information, function and cooperation. The followings are concluded; improving the inconsistency of system management, reducing operator's confusion caused by excessive display of AtoN AIS system, improving the problem of receiving unnecessary information, improving the functional problems caused by AIS communication inability and improving AtoN AIS information which is presently not used on board.

• Journal of Navigation and Port Research
• /
• v.45 no.1
• /
• pp.26-32
• /
• 2021

In ocean field, the spread of the Fourth Industrial Revolution based on information and communication technology requires high precision and stable PNT&D (Position, Navigation, Timing and Data). As the IMO (International Maritime Organization) and IALA (The International Association of Marine Aids to Navigation and Lighthouse Authorities) are requiring backup systems due to mitigate vulnerabilities and the increase of dependency on GNSS (Global Navigation Satellite System), Korea is conducting a research & development of R-Mode. An DGPS (Differentiate Global Positioning System) reference station that uses MF, an existing maritime infrastructure, and AIS (Automatic Identification System) base stations that use 34 integrity station and VHF will be utilized in this study to avoid redundant investment. Because there are radio shadow areas that display low signal levels in the west sea, the establishment of new R-Mode reference and integrity station will be intended to resolve problems regrading the radio shadow area. Because the frequency has a characteristic in that radio wave transmits well along the ground (water surface) in low frequency band, simulation and measurement were conducted therefore this paper to propose candidate sites for R-Mode reference and integrity station resulted through p wave's propagation characteristics analysis. Using this paper, R-Mode reference and integrity station can be established at appropriate locations to resolve radio shadow areas in other regions.

• Journal of Advanced Navigation Technology
• /
• v.26 no.6
• /
• pp.496-503
• /
• 2022

In the reality that the fishing population is decreasing and the single-man fishing vessels is increasing, mandatory equipment for navigation and radio equipments for the safety of fishing boats has continued to be added. Therefore, many equipment such as navigation, communication and fishing are installed in the narrow steering room, so it is very confusing and a number of monitors are placed in the front, which is a factor that degrades the function of maritime observation. To solve this problem, we studied an interface that integrates and operates to major radio facilities such as very high frequency-digital selective calling equipment (VHF-DSC), automatic identification system (AIS) and fishing boat location transmission device (V-pass) into one multi function display (MFD) based on LAN. In addition, IEC61162-450 UDP packets and IEC61162 sentence were applied to exchange data through link between MFD and radio equipments, and additional messages needed for each equipment and function were defined. The integrated MFD monitor is easily operated by the menu method, and the performance of the interface was evaluated by checking the distress and emergency communication functions related to maritime safety and the message transmission status by equipment.

• Strategy21
• /
• s.46
• /
• pp.239-276
• /
• 2020

The failure of early economic sanctions aimed at hurting the overall economies of targeted states called for a more sophisticated design of economic sanctions. This paved way for the advent of 'smart sanctions,' which target the supporters of the regime instead of the public mass. Despite controversies over the effectiveness of economic sanctions as a coercive tool to change the behavior of a targeted state, the transformation from 'comprehensive sanctions' to 'smart sanctions' is gaining the status of a legitimate method to impose punishment on states that do not conform to international norms, the nonproliferation of weapons of mass destruction in this particular context of the paper. The five permanent members of the United Nations Security Council proved that it can come to an accord on imposing economic sanctions over adopting resolutions on waging military war with targeted states. The North Korean nuclear issue has been the biggest security threat to countries in the region, even for China out of fear that further developments of nuclear weapons in North Korea might lead to a 'domino-effect,' leading to nuclear proliferation in the Northeast Asia region. Economic sanctions had been adopted by the UNSC as early as 2006 after the first North Korean nuclear test and has continually strengthened sanctions measures at each stage of North Korean weapons development. While dubious of the effectiveness of early sanctions on North Korea, recent sanctions that limit North Korea's exports of coal and imports of oil seem to have an impact on the regime, inducing Kim Jong-un to commit to peaceful talks since 2018. The purpose of this paper is to add a variable to the factors determining the success of economic sanctions on North Korea: preventing North Korea's evasion efforts by conducting illegal transshipments at sea. I first analyze the cause of recent success in the economic sanctions that led Kim Jong-un to engage in talks and add the maritime element to the argument. There are three conditions for the success of the sanctions regime, and they are: (1) smart sanctions, targeting commodities and support groups (elites) vital to regime survival., (2) China's faithful participation in the sanctions regime, and finally, (3) preventing North Korea's maritime evasion efforts.