• Journal of IKEEE
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• v.18 no.2
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• pp.228-233
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• 2014

In this paper, we propose a CMOS-memristor hybrid circuit that can perform 4-bit multiplication for future energy-efficient computing in nano-scale digital systems. The proposed CMOS-memristor hybrid circuit is based on the parallel architecture with AND and OR planes. This parallel architecture can be very useful in improving the power-delay product of the proposed circuit compared to the conventional CMOS array multiplier. Particularly, from the SPECTRE simulation of the proposed hybrid circuit with 0.13-mm CMOS devices and memristors, this proposed multiplier is estimated to have better power-delay product by 48% compared to the conventional CMOS array multiplier. In addition to this improvement in energy efficiency, this 4-bit multiplier circuit can occupy smaller area than the conventional array multiplier, because each cross-point memristor can be made only as small as $4F^2$.

• Journal of Drive and Control
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• v.16 no.2
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• pp.80-90
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• 2019

Fuel cell hybrid electric vehicle is an attractive solution to reduce pollutants, such as noise and carbon dioxide emission. This study presents an approach for energy management and control algorithm based on energetic macroscopic representation for a fuel cell hybrid electric vehicle that is powered by proton exchange membrane fuel cell, battery and supercapacitor. First, the detailed model of the fuel cell hybrid electric vehicle, including fuel cell, battery, supercapacitor, DC-DC converters and powertrain system, are built on the energetic macroscopic representation. Next, the power management strategy was applied to manage the energy among the three power sources. Moreover, the control scheme that was based on back-stepping sliding mode control and inversed-model control techniques were deduced. Simulation tests that used a worldwide harmonized light vehicle test procedure standard driving cycle showed the effectiveness of the proposed control method.

• Journal of ILASS-Korea
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• v.27 no.4
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• pp.195-202
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• 2022

Recently, the global automobile market is rapidly changing from internal combustion engine vehicles to eco-friendly vehicles including electric vehicles. Among eco-friendly vehicles, LPG vehicles are low in fine dust and are suggested as a realistic way to replace diesel vehicles. In addition, it is more economical than gasoline in its class, showing a cost-saving effect. In Korea, the business of converting gasoline into LPG is active. Research is being conducted to apply this to hybrid vehicles. In this study, the difference in energy consumption efficiency was analyzed when LPG fuel was applied by selecting a 2-liter GDI hybrid electric vehicle. The operation of the hybrid system according to various driving characteristics was confirmed by selecting the WLTC mode. As a result, it was confirmed that the BSFC was about 5% lower than that of gasoline fuel when using LPG fuel. This is due to the active operation of the motor while driving. Optimization is required as battery consumption increases from an energy perspective.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.3
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• pp.199-209
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• 2014

Crevice corrosion tests were conducted to examine the corrosion properties of HYBRID (HYdrazine Base Reductive metal Ion Decontamination) which was developed to decontaminate the PWR primary coolant system. To compare the corrosion properties of HYBRID with commonly existing decontamination agents, oxalic acid (OA) and citric oxalic acid (CITROX) were also examined. Type 304 Stainless Steel (304 SS) and Alloy 600 which are major components of the primary coolant system in Pressurized Water Reactor (PWR) were evaluated. Crevice corrosion tests were conducted under very aggressive conditions to confirm quickly the corrosion properties of primary coolant system structure components which have high corrosion resistance. Pitting and IGA were occurred in crevice surface under OA and CITROX conditions. But localized corrosion was not observed under HYBRID condition. Very low corrosion rate of less than $1.3{\times}10^{-3}{\mu}m/h$ was observed under HYBRID condition for both materials. On the other hand, under OA condition, Alloy 600 indicated comparatively uniform corrosion rate of $4.0{\times}10^{-2}{\mu}m/h$ but 304 SS indicated rapid accelerated corrosion in lower case than pH 2.0. In case of HYBRID condition, general corrosion and crevice corrosion were scarcely occurred. Therefore, material integrity of HYBRID in decontamination of primary coolant system in pressurized water reactor (PWR) reactor was conformed.

• Membrane Journal
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• v.28 no.2
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• pp.90-95
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• 2018

A process design was performed for a removal of acid gases using membrane-absorption hybrid system in LNG-FPSO. Commercial process simulator Promax version 4.0 was utilized for comparing acid gases removal capabilities of amine absorption process and hybrid process. Simulation results show hybrid process could be small amine solvent circulate rate, energy consumption, equipment sizing compared to typical amine absorption process. As a result, hybrid process which is small footprint and energy saving process may be a good solution for the pre-treatment of natural gas in LNG-FPSO.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7451-7458
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• 2014

In this paper, the system modeling and multi-agent control algorithm in isolated wind hybrid power systems are proposed. The multi-agent control is a new type of the hybrid control method that is made up of wind turbine, diesel generator, battery, and dumpload. Fourteen different modes of operations of the wind hybrid power system are performed by wind speed changes and the SOC of battery. Simulation results show that the efficient operations under various wind variations in isolated wind hybrid power systems can be obtained using proposed algorithms.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.81-86
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• 2012

The shock absorber is very important in various mechanical field. Without the shock absorber, the structure might be broken. For lunar lander, honeycomb shock absorber to absorber the shock by using plastic deformation of honeycomb has been used. It is cheap and simple to use but impossible using again without changing the honeycomb. The oleo-pneumatic type shock absorber is not able to use in the cosmos because it is vacuum and its temperature. This study suggests the hybrid shock absorber combined spring-ratchet mechanical shock absorber and eddy current electromagnetic damper. The ratchet restricts rebound of lunar lander and the spring converts the impact energy to the potential energy of the spring. The eddy current damper dissipates the impact energy by eddy current force without contact between the parts. This hybrid shock absorber is reusable while the honeycomb shock absorber isn't. The impact absorbing test of the hybrid shock absorber was carried out. This paper shows that the compared results the hybrid shock absorber with ratchet and without ratchet and evaluates the possibility of using for lunar lander.

• New & Renewable Energy
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• v.4 no.2
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• pp.52-60
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• 2008

More people have become interested in hybrid vehicles - which have been heralded as environmentally friendly automobiles - recently as the opening of domestic hybrid vehicle market draws near. Since gasoline, diesel and LPG hybrid vehicles will be produced, a need exists to conduct economic feasibility study of each vehicle type. This research analyzed projected benefits of these hybrid vehicles based on the 1600cc model. There are two categories of benefits: 1) reduced fuel costs for the owners of the vehicles; and 2) reduced environmental pollution cost. We conducted a sensitivity analysis and estimated the domestic consumer fuel costs based on the international oil prices of 100USD, 150USD, and 200USD per barrel. The analysis showed savings of 2 to 4 million Won in fuel cost and 1 to 2 million Won in environmental pollution cost; therefore, the hybrid vehicles are not economically feasible if they are between 3 to 5 million Won more expensive than the conventional internal combustion engine vehicles.

• Journal of the Korean Society for Advanced Composite Structures
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• v.4 no.2
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• pp.25-30
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• 2013

In this study a hybrid safety barrier system consisting of steel rail and carbon fiber reinforced polymer (CFRP) post is considered. W hile CFRP post is selected for impact energy reflection due to its high strength, steel rail is selected for impact energy absorption due to its high ductility. A numerical model considering the elastoplastic behavior of steel is formulated to simulate the dynamic responses of the hybrid system subject to an impact load. A hybrid roadside guard rail system of steel rail and CFRP post is proposed and analyzed with a case study. The numerical model for the hybrid roadside guard rail system is used to find optimized design of the proposed hybrid system.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.5
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• pp.38-43
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• 2011

This study was carried out to evaluate the structural stability of hybrid type fan heater. The evaluation of structural safety of hybrid fan heater was conducted by using Ansys Workbench and CFX-11 under the design condition. The hybrid fan heater was operated by heat transfer for heat source supplied from electric heater and combustion gas. According to result of structural analysis, the maximum equivalent stress of hybrid fan heater was 150MPa when the temperature of heat transfer fluids was $150^{\circ}C$. It was found that the hybrid fan was structurally safe because the value of maximum equivalent stress was smaller than that of yield stress of the material.