• Journal of Navigation and Port Research
• /
• v.29 no.1 s.97
• /
• pp.23-28
• /
• 2005

The signal in wireless multi-path channel is affected by fading and ISI because of high data rate transmission, so the signal has the high error rate. The present modulation and demodulation method of DSRC system can not expect sufficient for providing data service over 1 Mbps, so the channel equalization and advanced modulation and demodulation methods are required. OFDM is generally known as an effective technique for high data rate transmission system, since it can prevent ISI by inserting a guard interval. However, a guard interval longer than channel delay spread has to be used in each OFDM symbol period, thus resulting a considerable loss in the efficiency of channel utilization Therefore the equalizer is necessary to cancel ISI to accommodate advanced ITS service with higher bit rate and longer channel delay spread condition In this paper, the channel equalizer for the OFDM -DSRC system was designed and its performance in a multi-path fading environment was evaluated with computer simulation.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2020.11a
• /
• pp.54-55
• /
• 2020

In 4th Industrial Revolution, technologies such as artificial intelligence, Internet of Things, and Big data are closely related to the maritime industry, which led to the birth of autonomous vessels. Due to the technical characteristics of the current vessel, the speed cannot be suddenly lowered, so complex communication such as the help of a tug boat, boarding of a pilot, and control of the vessel at the onshore control center is required to berth at the port. In this study, clustering analysis was used to resolve how to establish control criteria for vessels to enter port when autonomous vessels are operating. K-Means clustering was used to quantitatively stage the arrival pattern based on the accumulated AIS(Automatic Identification System) data of the incoming vessel, and the arrival phase using SOG(Speed over Ground), COG(Course over Ground), and ROT(Rate of Turn) Was divided into six phase.

• Journal of Advanced Navigation Technology
• /
• v.18 no.3
• /
• pp.201-208
• /
• 2014

Due to diversification of ships and limited space of pier, when ships come alongside the shallow water or narrow pier, sea area with small mooring facilities and floating matter is frequently applied. Through these, coming alongside the various space is capable and cost effectiveness is enhanced. However, when ships, applying small mooring facilities and floating matter, come alongside, there can be some impulse by waves between the floating things and ships which possibly leads to mass disaster. Therefore, there should be forecasts and analysis of the movement caused by waves. On this study, we develop measuring system for movement analysis of mooring and floating matters which provides base data with movement traits by measuring 3-D exercise information and acceleration at mokpo maritime university marina facility. Also, the composition and principles of the developed system is explained.

• Journal of Navigation and Port Research
• /
• v.34 no.10
• /
• pp.769-774
• /
• 2010

The performance of underwater communication system is influenced on channel characteristic. Delay spread cause by reverberation and multi-path happen the ISI (Inter Symbol Interference) and reduces the communication performance. In this paper, we analyze the performance of acoustic communication experiment in underwater to use the OFDM (Orthogonal Frequency Division Multiplexing) technique for overcome the reverberation and multi-path. As a result, we acquired the BER of modulation techniques. The BER of 2kbps data rate is $1.22{\times}10^{-1}$ and BER of 4 kbps data rate is $2.47{\times}10^{-2}$.

• Proceedings of the Korean Information Science Society Conference
• /
• 2008.06d
• /
• pp.480-484
• /
• 2008

DNP3.0은 산업 분야에서 SCADA(Supervisory Control And Data Aquisition) system의 개방형 프로토콜로 사용되어지고 있다. 본 논문에서는 개발하거나 개발된 Module들 사이에서 송 수신되는 DNP3.0 PDU를 분석할 수 있는 기능을 제공하는 DPA(DNP3.0 Protocol Analyzer) Module을 설계 및 구현하였다. 해당 Master Station에서 Request 메시지를 생성하여 Outstation으로 전송하고 Outstation에서 수신된 Request 메시지를 분석하여 Response 메시지를 생성하여 Response 한다. 또한 Master Station 과 Outstation에서 DNP3.0 프로토콜을 사용하여 통신하는 중간에서 송 수신하는 메시지를 Monitoring한다.

• Journal of information and communication convergence engineering
• /
• v.8 no.3
• /
• pp.289-294
• /
• 2010

In the vehicle communication system, transferred information is needed to be detected as possible as fast in order to inform car status located in front and rear side. Through the moving vehicle information, we can avoid the crash caused by sudden break of front one or acquire to real time traffic data to check the detour road. To be connecting the wireless communication between the vehicles, fast timing synchronization can be a key factor. Finding out the sync point fast is able to have more marginal time to compensate the distorted signals caused by channel variance. Thus, we introduce the combination method which helps find out the start of frame quickly. It is executed by auto-correlation and cross-correlation simultaneously using only short preambles. With taking the absolute value at the implemented synch block output, the proposed method shows much better system performance to us.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2009.06a
• /
• pp.425-431
• /
• 2009

Recently, new technology has been introducing according to the efforts for maritime safety, traffic and environmental protection that uses electronic method to make use of maritime information effectively. To be associated with the tendance, international society which centered to IALA Introduces advanced technology of AtoN with Automatic Identification System(AIS) that it is crucial method to collect and transmit maritime data. This article is to thoroughly analyse and investigate the international and national regulation of related AtoN AIS, and propose to be included and applied into national radio-communication equipment regulation.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39C no.2
• /
• pp.184-190
• /
• 2014

Until now ship communication micro serial network communication method is designed for the communication between the controller and the RS-422 communication on the international standard ISO 1993, but gradually progresses NMEA 2000 standardized fast Ethernet-based communications environments expected to be replaced. In addition, the ship's main instrumentation equipment versatility with ease gradually to control devices by monitoring and controlling are. Wind anemometer, ship mast end, where the highest wind farms typically install a separate console boxes, data loggers, indicators was required in order to manage them, to maintain them, to go through the procedures and cumbersome data update firmware were Therefore, in this paper, using the PC network, ultrasonic wind speed data processing system for implementing functional was expressed as a function of the technology elements, NMEA 2000 standard certified in separate operating console without the features of the data loggers, indicators, implementation by ultrasonic wind data processing system was implemented to minimize the maintenance cost of the operating system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2015.10a
• /
• pp.43-44
• /
• 2015

AIS-ASM is a one of the study to provide a variety of maritime safety information as well as ship's position and navigational information that is their own function since 2004. This study aims to reduce the marine officer's workload through automating marine officer's mandatory reporting items using the one of the next maritime digital communication technology (ASM2.0). For this purpose, we designed and experimented of the ASM2.0 protocol through analyzing a domestic regulation about passenger flight and AIS-ASM message.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.1
• /
• pp.77-82
• /
• 2006

Automatic vessel collision-avoidance systems have been studied in the fields of artificial intelligence and navigation for decades. And to facilitate automatic collision-avoidance decision-making in two-vessel-encounter situation, several expert and fuzzy expert systems have been developed. However, none of them can negotiate with each other as seafarers usually do when they intend to make a more economic overall plan of collision avoidance in the COLREGS-COST-HIGH situations where collision avoidance following the International Regulations for Preventing Collisions at Sea(COLREGS) costs too much. Automatic Identification System(AIS) makes data communication between two vessels possible, and negotiation methods can be used to optimize vessel collision avoidance. In this paper, a negotiation framework is put forward to enable vessels to negotiate to optimize collision avoidance in the COLREGS-COST-HIGH situations at open sea. A vessel vector space is defined and therewith a cost model is put forward to evaluate the cost of collision-avoidance actions. Negotiations between a give-way vessel and a stand-on vessel and between two give-way vessels are considered respectively to reach overall low cost agreements. With the framework proposed in this paper, two vessels involved in a COLREGS-COST-HIGH situation can negotiate with each other to get a more economic overall plan of collision avoidance than that suggested by the traditional collision-avoidance expert systems.