• Journal of Advanced Marine Engineering and Technology
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• v.36 no.6
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• pp.780-787
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• 2012

In general, the ocean wave vibration power generator consists of buoy, vibration system and linear generation system. It maximized energy efficiency by using resonance phenomenon that turned to the natural frequency of vibration system and frequency of ocean wave energy. But it is difficult to obtain efficiently energy from ocean wave because the frequency of ocean wave changes from moment to moment. In this paper, we study the buoy and vibration system of ocean wave power generator to solve these problem. Firstly, we designed the buoy that gives rise to resonance between ocean wave and buoy. Secondly, we designed vibration system that is occurred to resonance between buoy and vibration system. And then the relative velocity between the buoy and magnetic of ocean wave vibration generator increases and the relative displacement between buoy and ocean wave decreases at the same time. As a result, the method which is proposed in this paper has merits not only securing its stability from harsh ocean wave environment but also obtaining more kinetic energy from ever-changing ocean wave.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.6
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• pp.557-563
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• 2016

The energy absorption efficiency of a wave power generation system is calculated as the ratio of the wave power to the power of the system. Because absorption efficiency depends on the dynamic behavior of the wave power generation system, a dynamic analysis of the wave power generation system is required to estimate the energy absorption efficiency of the system. In this study, a dynamic analysis of the wave power generation system under wave loads is performed to estimate the energy absorption efficiency. RecurDyn is employed to carry out the dynamic analysis of the system, and the Morison equation is used for the wave load model. According to the results, the lower the wave height and the shorter the period, the higher is the absorption efficiency of the system.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1028-1034
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• 2011

This paper have been studied that ocean wave power vibration generation system with two D.O.F.(degree of freedom) consists of buoy and vibration generation system with two D.O.F. for using efficiency of ocean wave energy. It selected main frequencies ${\omega}_1$, ${\omega}_2$ in frequency with ocean wave and it fitted them to the natural frequencies of vibration system with two D.O.F. in the vibrational power generation system. Then each the relative velocity of between the winding coil and the permanent magnet is faster than the velocity of ocean wave up and down motion by resonance phenomenon. Also the ocean wave power generation with two D.O.F. obtained the more electric energy then the ocean wave power generation with one D.O.F. by coupling effect for two D.O.F. vibration system. Therefore ocean wave power vibration generation system with two degree of freedom that is proposed in this paper has merits which not only using more energy in the ocean wave but also obtaining more electronic energy.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.5
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• pp.61-72
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• 2013

Next-generation ITS(Intelligent Transportation System) adopts WAVE(Wireless Access in Vehicular Environment) system which is capable of the bidirectional communication system in vehicular environments. u-Transportation system adopted WAVE communications system to show the optimal performance in terms of various services with regard to vehicle safety and traffic. In this paper, we introduce testbed of ubiquitous-Transportation system and its service. Then, we describe WAVE system for supporting next-generation ITS service. Also, we carried out tests in real road environments in order to verify communication functions of WAVE systems and its performance. We confirmed that our communication systems for supporting services meet the communication performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.2
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• pp.257-263
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• 2013

In this study, dynamic behaviors of a wave energy generation system (WEGS) that converts wave energy into electric energy are analyzed using multibody dynamics techniques. Many studies have focused on reducing the effects of a mooring system on the motion of a WEGS. Several kinematic constraints and force elements are employed in the modeling stage. Three-dimensional wave load equations are used to implement wave loads. The dynamic behaviors of a WEGS are analyzed under several wave conditions by using MSC/ADAMS, and the rotating speed of the generating shaft is investigated for predicting the electricity capacity. The dynamic behaviors of a WEGS with a mooring system are compared with those of a WEGS without a mooring system. Stability evaluation of a WEGS is carried out through simulation under extreme wave load.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.1
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• pp.176-185
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• 2017

This paper describes a design of the WAVE antenna system in V2X wireless communication systems for Intelligent Transport Systems. The WAVE standard protocols defined 5.825~5.9GHz frequency range for wireless communications with V2X. In a recent, A study of WAVE communication system it has been studied mainly the base station and the OBU technology in order to improve the communication performance of the communication distance. In this paper, the proposed vehicular WAVE antenna using the EBG structure is to improve performance. The proposed WAVE antenna with EBG shows improvement of return loss and radiation beam pattern. The performance of WAVE communication systems for intelligent transport systems is dependent on the performance of antenna. The proposed vehicular antenna for WAVE communication systems shows improvement of return loss for performance.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.861-866
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• 2011

This paper described the hybrid power generation using ocean wave that consists of linear power generation system and vibrational power generation system. The linear power generation system is made up of the winding coil, the permanent magnet and it is performed stable generation regardless of the wave frequency using directly the ocean wave velocity. And the vibration power generation system consists of the winding coil, the permanent magnet and spring. When the vibration system natural frequency in the vibrational power generation system is tuned to the ocean wave frequency, the relative velocity of between the winding coil and the permanent magnet is faster than the velocity of ocean wave up and down motion, then we can obtain more the electric power. Therefore, in this paper, the proposed hybrid power generation using ocean wave have merits that obtaining the more electric energy in resonance frequency and carrying out stable generation even over the range of resonance frequency.

• Journal of Advanced Navigation Technology
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• v.13 no.4
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• pp.544-550
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• 2009

In this paper, we proposed the radio wave propagation characteristics of the next-generation ultrafast wireless communication system in millimeter-wave fading channel. For considering doppler shift and Rayleigh fading simultaneously, the fading simulator of Jakes model implemented and analyzed the performance of the next-generation wireless communication system. In addition, the error rate characteristics of DS-CDMA system analyzed in the millimeter-wave fading channel and the system performance improved by coding technique and diversity technique.

• Journal of Navigation and Port Research
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• v.33 no.6
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• pp.381-385
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• 2009

Generally power system of ocean facility composes a solar generation system.The power to be generated by the solar system is changed according to the amount of sunlight of weather conditions. Output power of solar system is decreased with weather condition such as cloudy day and rainy day. And the power shortage of the ocean facility can occur due to the lack of solar energy. To solve this problem, this paper proposes the power control system for solar-wave hybrid system Wave generation system consists of wells turbine and permanent magnet synchronous generator(PMSG). This propose system set the specific area and measures the solar generation power and wave generation power. As a result of experiment, the solar power is a more static source than wave power, but the wave power provides energy during periods of no sunshine. The power characteristic of propose hybrid system have been obtained high reliability than a solar generation system.

• Journal of Advanced Navigation Technology
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• v.12 no.4
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• pp.341-349
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• 2008

In this paper the Coefficient Tracking Synchronization Algorithm is proposed for the compensation and the suitability of the fast channel fluctuation OFDM in the WAVE(Wireless Access in Vehicular Environments) system. The in progress of standardization WAVE process, IEEE802.11p's physical layer is considered on the coexistence of fading and Frequency offset of OFDM channel to find the system performance ability and the comparing examination which is taken on the proposed method of Coefficient Tracking Synchronization Algorithm and the performance efficiency. Through the simulation result we also can see that the proposed system improves the channel estimation ability and offers an extra efficiency if compared to the existing method.