• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.2
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• pp.224-230
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• 2012

Thermal batteries have excellent mechanical robustness, reliability, and long shelf life. Due to these characteristics as well as their unique activation mechanism, thermal batteries are widely adopted as military power sources. Li(Si)/$FeS_2$ thermal batteries, which are used mostly in these days, use LiCl-KCl and LiBr-LiCl-LiF as molten salt electrolyte. However, it is known that Li(Si)/$FeS_2$ thermal batteries have high internal resistance. Especially, $FeS_2$ cathode accounts for the greater part of internal resistance in unit cell. Many efforts have been put into to decrease the internal resistance of thermal batteries, which result in the development of new electrode material and new electrode manufacturing processes. But the applications of these new materials and processes are in some cases very expensive and need complicated additional processes. In this study, internal resistance study was conducted by adding carbon black and carbon nano-tube, which has high electron conductivity, into the $FeS_2$ cathode. As a results, it was found that the decrease of internal resistance of $FeS_2$ cathode by the addition of carbon black and carbon nano-tube.

• Journal of Navigation and Port Research
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• v.31 no.10
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• pp.839-844
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• 2007

This paper describes the performance of DC-DC converters for buoy such as buck, boost, and buck-boost. The operating characteristic and charging efficiency with battery, which has a considerable properties about converters with PV(photovoltaic) system, is analyzed in this paper. It is performed by using the MPPT(Maximum Power Point Tracker) algorithm The basic equations of switching operation for converter are described, and the equations are analyzed with according to switch state. Whereas this analysis is directed toward the selection of converter for buoy, it also provides the insight into the behaviour of converter and performance of the proposed algorithm Finally, the suitable DC-DC converter is proposed for buoy, and the characteristic experiment is performed with the buck converter.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7B
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• pp.886-891
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• 2011

Multicast has been a key routing service for efficient data dissemination in underwater acoustic sensor networks. In sensor networks, there are several multicast routing protocol which reflects sensor network nature. However, existing routing scheme was not targeted at underwater acoustic sensor networks which is hard to provide battery continually. Therefore, a specialized routing algorithm is essential for acoustic sensor networks. In this paper, we propose angle aided multicast routing algorithm for decreasing routing computation complexity, including virtual Euclidean Steiner point. Simulation results show better performance than exist routing Position Based Multicast, Geographic Multicast Routing. such as low computation capability and limited power consumption.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.132-134
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• 2007

하이브리드 차량 및 전기차량 구동 모터의 권선저항에 의한 손실 및 모터의 크기를 줄이기 위해 고효율, 고승압형 DC-DC 컨버터 사용이 요구된다. 기존의 부스트 컨버터는 기생저항 성분에 의해 고승압이 불가능하여 변압기를 사용하여 승압비를 향상시킨 current-fed push-pull, current-fed full bridge, dual inductor-fed 부스트 컨버터 등으로 변형되어 사용되어 왔다. dual inductor-fed 부스트 컨버터의 경우 동일조건하에서 앞서 기술된 2가지 컨버터보다 2배의 승압비를 얻을 수 있으며 1차측 전류 스트레스가 낮은 장점을 가지고 있어 대전력, 고승압 응용에 적합하다. 하지만 변압기의 누설인덕턴스에 의한 써지성 전류/전압을 제한하기 위한 부가적인 snubber회로의 사용으로 효율을 떨어뜨리게 되는 단점을 가지고 있다. 본 논문에서는 이러한 단점을 보완할 수 있는 새로운 2개의 인덕터와 1개의 변압기를 갖는 DC-DC 컨버터를 제안한다. 제안된 컨버터의 동작원리와 모드해석을 실시하고 최종적으로 400W, 42Vdc (Battery)/400Vdc (Electric Motor) 실험결과를 통해 이를 검증한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.299-305
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• 2003

The battery industries have been developed to the implementation of lithium ion secondary cell from the cell of Ni/Cd and Ni/MH in the past to be asked of an age of high technology from low technology. Also in resent the polymeric cell to get a good high function with an age of new advanced information system is changed from the 21 century to the secondary batteries society. The properties of lithium secondary batteries have the high energy density, the long cycle time, the low self discharge area and the high active voltage. The wanted properties of secondary batteries for the motion of an apparatuses of industries of an high skill age have a small type trend of the energy density and it is become with a strong asking of the industrial society market about the storable medium of the convenience and new power energy. The electrochemical properties is researched for the cell to be synthesised and crystallized the positive active material LiMnO2 of the secondary cell at 9250C to get a new improved data of the electric discharge for that the capacitance of the LiMnO2 thin film that is improving and researching with the properties and a merit and demerit in the this kind of asking.

• Journal of Energy Engineering
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• v.26 no.1
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• pp.28-33
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• 2017

A liquid nitrogen engine is a highly clean power engine, which does not emit any hazardous substances in its fumes. Additionally, it has an advantage over electric vehicles, as its energy density is larger than that of a battery. The use of an existing liquid nitrogen engine is typically limited to the reciprocation type. In this study, the concept of a nitrogen engine equipped with a scroll expander is introduced. The engine's efficiency was shown to increase when the scroll expander was utilized in the engine, while also adding to the simplification of the structure. Therefore, compared to the existing reciprocation-type engine, the engine with the scroll expander has the potential to be both technically and economically more competitive. In this study, the performance of a liquid nitrogen engine equipped with a scroll expander was analyzed while altering the injection pressure profile of liquid nitrogen.

• Journal of Sensor Science and Technology
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• v.24 no.2
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• pp.124-130
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• 2015

This paper presents a high performance HIGHT processor that can be applicable for CCM mode. In fact, HIGHT algorithm is a 64-bit block cipher. However, the proposed HIGHT extends the basic block length to 128-bit. The proposed HIGHT is operated as 128-bit block cipher and it can treat 128-bit block at once. Thus, it can be applicable for the various WSN applications that need fast and ultralight 128-bit block cipher, in particular, to be operated in CCM mode. In addition, the proposed HIGHT processor shares the common logics such as 128-bit key scheduler and control logics during encryption and decryption to reduce the area overhead caused by the extension of data block length. From the simulation results, the circuit area and power consumption of the proposed HIGHT are increases as 40% and 64% compared to the conventional 64-bit counterpart. However, the throughput of the proposed HIGHT can be up to two times as fast. Consequently, the proposed HIGHT is useful for USN and handheld devices based on battery as well as RFID tag the size of circuit is less than 5,000 gates.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.258-260
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• 2017

Smart mobility is rapidly emerging as a next-generation eco-friendly transportation system, and the market is booming every year. However, due to the characteristics of the devices that use electricity as the power source, the motor and the battery are different from the performance and actual performance indicated by the manufacturer depending on the user's weight and driving environment. Therefore, The frequency of the overload is increased and the failure and damage of the device are increasing. In this paper, we propose an application that provides personalized recommended driving guidance and overloaded driving situation notification at the actual driving separately from the recommended driving provided by the manufacturer after measuring the driving environment of the user, so as to prevent malfunction and damage of the smart mobility device, To ensure safety.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6258-6263
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• 2014

The LDC (Low Voltage DC-DC Converter) used for hybrid vehicles and electric vehicles was utilized to supply the electric apparatus load with a voltage and to charge the auxiliary batteries by receiving a high DC voltage from the high voltage battery. The LDC has a long-time load test during the manufacturing process. On the other hand, it has the disadvantage of considerable energy consumption because it has the structure to release the power as 100% heat during a load test. Therefore, in this paper, a recycling load test method was proposed and 75~90% energy saving was realized.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.46-46
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• 2007

There has been rapid progress in the portable electronics industry. which has led to a great increase for a demand of portable, lightweight power sources. Lithium 2'nd batteries have met these demand. and many studies on the cahtod materials for the lithium 2,nd batteries have been reported during the last decade. Possible candidates for the cathode materials for lithium 2,nd batteries are $LiCoO_2$, $LiNiO_2$, and $LiMn_2O_4$. Currently $LiCoO_2$ is widely used. but $LiMn_2O_4$ is an excellent alternative material in view of its several advantages such a low cost as well as the wasy availability of raw materials and environmental benignity. In this study, find the most suitable synthesis method that satisfied high capacitor and stability cycle character, etc in Li-Mn oxide for 2'nd batteries. And also made an experiment on doping the $LiMn_2O_4$ spinel with a small amount of metal ions has a remarkable effect on the electrochemical properties and characterics of powder, BET, PSA, Porosity, etc.