• Journal of Navigation and Port Research
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• v.30 no.7
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• pp.607-610
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• 2006

A new compact microstrip low-pass filter and its equivalent-circuit model are developed. The philosophy of the structure behind this novel microstrip low-pass filter is simple as it is composed of a pair of symmetrical parallel coupled-line and an open-stub. With this configuration, a finite attenuation pole near the stopband cutoff frequency is available and adjustable by simply tuning the circuit parameters. Furthermore, the rejection bandwidth of this type of low-pass filter can be extended. In order to validate the feasibility of the proposed design method, a low-pass filter based on a microstrip structure is designed, fabricated, and measured. Experimental results agree very well with the simulation and analytical results.

• Journal of Navigation and Port Research
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• v.42 no.2
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• pp.79-86
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• 2018

Common Maritime Data Structure (CMDS) is commonly used by shore and ship users in e-Navigation data domain. In the overarching of e-Navigation architecture, IHO uses S-1XX, a digital exchange standard for next-generation marine information, as data exchange standard. The current CMDS has the advantage of intuitively recognizing the overall structure of e-Navigation. However, it has disadvantage in that it does not allow stakeholders to easily understand benefits that e-Navigation can provide when implementing e-Navigation. In this study, the direction of improving existing system for effective e-Navigation implementation was proposed considering RCOs (Risk Control Options) with expected composition of ship/ shore/ communication system by sector.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.10 no.6
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• pp.287-295
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• 1985

Analysis and design procedures for the symmetrical and non-symmetrical interdigitated four-port microstrip couplers conssiting of symmetrical three lines is presented. The configuration is simple and a lesser number of bond wires are requires as compared to the four-line couplers which are used. Physical dimensions of 3. 6 and 10dB couplers with substrates having typical dielectric constant values of 2.55 and 10 can be found by using the tables and charts.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.10a
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• pp.79-84
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• 2006

A novel design of compact low-pass filter based on microstrip structure and its equivalent-circuit model are developed. The philosophy of the structure behind this novel microstrip low-pass filter is simple as it is composed of a pair of symmetrical parallel coupled-line and an open-stub. With this configuration, a finite attenuation pole near the stopband cutoff frequency is available and adjustable by simply tuning the circuit parameters. Furthermore, the rejection bandwidth of this type of low-pass filter can be extended. In order to validate the feasibility of the proposed design method, a low-pass filter based on a microstrip structure is designed, fabricated, and measured. Experimental results agree very well with the simulation and analytical results.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.247-250
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• 2006

Integrating a GPS based vehicle navigation system and the latest optimal algorithms, this research aims to develop a real-time decision support platform for concrete plant to provide the optimal solutions for ready mixed concrete delivery. The platform includes fleet tracking system, simulation and optimization tools, and visual interface which is useful to monitor delivery progress, to obtain crucial historical and real-time data for simulation, and to improve the efficiency of the plant operation. This paper presents configuration of the system and performance evaluation based on operational data.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.285-290
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• 2006

This paper presents an adaptive neural network based controller and its application to Dynamic Positioning (DP) control system of ship. The proposed neural network based controller is developed for station-keeping and low-speed maneuvering control of ship. At first, the DP system configuration is described. And then, to validate the proposed DP system, computer simulations of station-keeping and low-speed maneuvering performance of a multi-purpose supply ship are presented under the influence of measurement noise, external disturbances such as sea current, wave, and wind. The simulations have shown the feasibility of the DP system in various maneuvering situations.

• Journal of Navigation and Port Research
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• v.31 no.9
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• pp.759-762
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• 2007

A novel miniaturized CMOS C-Band bandpass filter based on diagonally end-shorted coupled lines and interdigital capacitors is proposed. The utilized coupled lines structure reduced the configuration in size, as small as a few degrees. Moreover, the characteristic of interdigital capacitor, relatively high Q and good capacitance tolerance, accounts for the satisfied performance of this new filter. A two-stage bandpass filter was designed and fabricated with chip surface area only $1.02{\times}1.4\;mm^2$.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.2
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• pp.8-17
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• 1992

In this paper a push-push oscillator using DR (dielectric resonator) at K-band is designed and constructed. Two identical oscillators are arranged in a push-push configuration that has the frequency of oscillator that is twice frequency each oscillator. A dielectric resonator is placed at the input of an active two-port device(FET) yielding a stable frequency source. The oscillators realized with this technique exhibit excellent spectral purity and cancellation of fundamental frequency.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.10
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• pp.2773-2778
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• 1994

Tumbling motion is very effective for turbulence enhancement during compression process in the cylinder of 4-valve engines. In this paper the tumble decay mechanism for different intake port configuration were measured using laser Doppler velocimetry. Analysis of the tumble decay mechanism was achieved by means of two non-dimensional parameters, defined as tumble eccentricity and shape factor in tumble velocity profile, in addition to the tumble moment.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.1
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• pp.26-33
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• 2007

The intake swirl motion, as one of dominant effects for an engine combustion. is very effective for turbulence enhancement during the compression process in the cylinder of 2-valve engine. Because the combustion flame speed is determined by the turbulence that is mainly generated from the mean flow of the charge air motion in intake port system. This paper describes the experimental results of swirl flow and combustion characteristics by using the oil spot method and back-scattering Laser Doppler velocimeter (LDV) in 2-valve single cylinder transparent LPG engine using the liquid phase LPG injection. For this. various intake port configurations were developed by using the flow box system and swirl ratios for different intake port configurations were determined by impulse swirl meter in a steady flow rig test. And the effects of intake swirl ratio on combustion characteristics in an LPG engine were analyzed with some analysis parameters that is swirl ratio. mean flow coefficient, swirl mean velocity fuel conversion efficiency. combustion duration and cyclic variations of indicated mean effective pressure(IMEP). As these research results, we found that the intake port configuration with swirl ratio of 2.0 that has a reasonable lean combustion stability is very suitable to an $11{\ell}$ heavy-duty LPG engine with liquid phase fuel injection system. It also has a better mean flow coefficient of 0.34 to develope a stable flame kernel and to produce high performance. This research expects to clarify major factor that effects on the design of intake port efficiently with the optimized swirl ratio for the heavy duty LPG engine.