• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.2
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• pp.63-70
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• 1996

In this paper, we propose the low sldelobe digital doppler filter bank design algorithm which is practically applicable to coherent radar equipment in complex air-defense system. Using the proposed algorithm, we can obtain a digital doppler filter bank of lower peak sidelobe level and higher clutter suppression capability. In this method, it is possible to achieve higher target-detectability without loss of Target SNR. The proposed algorithms are verified by simulations and experiments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.163-167
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• 1999

The relational data model can't be applied to CAD/CAM, CE, and CIM since it can't support the semantic model concept such as complex object, random data definition, manipulation, version control, generalization, aggregation and so on. In this paper, the IPCS(Integrated Production Control System) for hand-rail of ship is parted into several module according to process function. further more, the object oriented data model is designed with UML(Unified Modeling Language). UML is the object oriented design methodology of industrial standard that combines the Booch's methodology, the Rumbaugh's On(Object Modeling Technique), and the Jacobson's OOSE(Object-Oriented Software Engineering) methodology. The efficient management is expected with object-oriented data model construction, since this developed system can achieve efficient process control, system maintenance, repair and extension.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.519-526
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• 2016

As marine accidents happen frequently, it is required to establish a marine traffic monitoring system, which is designed to improve the safety and efficiency of navigation in VTS (Vessel Traffic Service). For this aim, recently, X-band marine radar is used for extracting the sea surface information and, it is necessary to retrieve wave information correctly and provide for the safe and efficient movement of vessel traffic within the VTS area. In this paper, three different current estimation algorithms including the classical least-squares (LS) fitting, a modified iterative least-square fitting routine and a normalized scalar product of variable current velocities are compared with buoy data and then, the iterative least-square method is modified to estimate wave information by improving the initial current velocity. Through several simulations with radar signals, it is shown that the proposed method is effective in retrieving the wave information compared to the conventional methods.

• Journal of Navigation and Port Research
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• v.31 no.6
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• pp.497-502
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• 2007

The important purposes of research in ship operation are to ensure safe navigation, high efficiency of transportation, high accuracy, and security. IMO, develops a broad strategy for incorporating the use of new technologies in a structured way to ensure that their use is compliant with the various electronic navigational and communication technologies and services that are already available. As a base research for E-Navigation, therefore, this paper proposes a maritime information network based on Mesh Network that is one of the maritime broadband solutions. Firstly, this paper analyzes an international port network system and the requirements of port network for E-Navigation. Finally, it designs the maritime information network system based on Mesh Network and shows its validity for E-Navigation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2355-2362
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• 2016

Seg fog removal is an important issue concerned by both computer vision and image processing. Sea fog or haze removal is widely used in lots of fields, such as automatic control system, CCTV, and image recognition. Color image dehazing techniques have been extensively studied, and expecially the dark channel prior(DCP) technique has been widely used. This paper propose a fast and efficient image prior - dark channel prior to remove seg-fog from a single digital image based on the GPU. We implement the basic parallel program and then optimize it to obtain performance acceleration with more than 250 times. While paralleling and the optimizing the algorithm, we improve some parts of the original serial program or basic parallel program according to the characteristics of several steps. The proposed GPU programming algorithm and implementation results may be used with advantages as pre-processing in many systems, such as safe navigation for ship, topographical survey, intelligent vehicles, etc.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.12
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• pp.1267-1279
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• 2014

In this paper, we suggest the development of object detection systems for the safety of the ship through the study of the properties of short-range radar. Many of the short-range radars developed for special purpose like cars has cheaper price advantages but it is not proper to every application. In order to overcome such obstacles we need to analysis data from experiments in various environments and feature analysis of the device is essential. Also, the data clustering algorithms to display correct classified moving objects is necessary. In this paper we propose the advanced fast moving object detection system using short range radars with better detection accuracy. And we proposed a clustering algorithm using the value of the RCS and the speed and trajectory information of the radar data that are reflected.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.1
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• pp.23-28
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• 2016

In this paper, a Multi-Band Ku-band down converter was designed for reception of multi-band digital satellite broadcasting. The Multi-band low-nose down converter was designed to form four local oscillator frequencies (9.75, 10, 10.75 and 11.3GHz) representing a low phase noise due to VCO-PLL with respect to input signals of 10.7 to 12.75GHz and 3-stage low noise amplifier circuit by broadband noise matching, and to select an one band of intermediate frequency (IF) channels by digital control. The developed low-noise downconverter exhibited the full conversion gain of 64dB, and the noise figure of low-noise amplifier was 0.7dB, the P1dB of output signal 15dBm, and the phase noise -73dBc@100Hz at the band 1 carrier frequency of 9.75GHz. The low noise block downconverter (LNB) for receiving four-band digital satellite broadcasting designed in this paper can be used for satellite broadcasting of vessels navigating international waters.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.469-478
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• 2000

On the advent of digital era, ECDIS has emerged as a new navigation aid that should result in significant benefits to safe navigation. More than simply a graphics display, ECDIS is a new concept navigation system capable of providing integrated information of geographical and texual data. As an official vector data for ECDIS, ENC consists of spatial and feature data to describe objects in form of points, lines and areas. IHO published International Standards for ENC, such as S-52(Specification for Chart Content and Display Aspects of ECDIS) and S-57(IHO Transfer Standard for Digital Hydrographic Data). This paper deals with the implementation of an ENC representation system which meets S-52 presentation specification and S-57 transfer standards by analyzing S-57 data structures and converting them to an appropriate internal data structures and representing them onto screen adopting S-52 presentation specification.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.1
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• pp.85-92
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• 2017

Recently, electric propulsion systems are used for unmanned surface vehicle, fish finder boat, etc. Some of these propulsion systems can be constructed of two electric motors and propellers for advanced impellent force. In this case, the speed difference generated between two propellers, namely, the synchronous error has a bad influence on the energy efficiency and course error. In this study, a synchronous control system is designed to restrain synchronous error caused by disturbance and mismatched dynamic characteristics. The control system is composed of the reference model, pre-filters, speed controllers, and synchronous controllers. The reference model is used for calculating the decoupled synchronous error and control input for each propulsion system. The pre-filters and speed controllers are designed in order that the propulsion system may follow the reference signal without overshoot and input saturation. And the synchronous controllers are designed from the viewpoint of stable and quick synchronization through root locus mothed approach. Finally, the simulation results show that the designed control system is effective for the disturbance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5A
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• pp.466-473
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• 2010

Several protocols which are based on tree topology to guarantee the important metrics such as energy efficiency in sensor networks have been proposed. However, studies on the effect of topologies in sensor networks, where base node has a high mobility, are very few. In this paper, we propose a minimum Wiener index tree as a suitable topology to the wireless sensor networks with high mobile base node. The minimum Wiener index spanning tree problem which aims to find a tree with minimum Wiener index from a given weighted graph was proved to be NP-hard. We designed a branch and bound algorithm for this problem. To evaluate the performance of proposed tree, the comparisons with minimum spanning tree in terms of transmission distance, energy consumption during one round, and network lifetime was performed by simulations. Our proposed tree outperformed in transmission distance and energy efficiency but underperformed in lifetime.