• 한국융합학회논문지
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• 제8권6호
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• pp.219-226
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• 2017

무인항공기 산업이 성숙해짐에 따라 촬영, 정찰, 구조 등 많은 분야에 무인항공기가 적용되고 있으며, 이로 인하여 신속한 무인항공기의 하드웨어의 설계, 특히 배터리팩의 설계가 필요하게 되었다. 수직이착륙 형태의 배송용 무인항공기의 편리한 배터리팩 구성 설계를 위한 자동 배터리팩 설계 툴을 개발하였다. 전류, 전압 패턴, 여러 셀 사양, 원하는 배터리팩 전압 등의 입력을 하면, 자동 배터리팩 설계 툴이 균질 셀 또는 이종 셀들을 결합하여 최소 중량과 최대 용량을 갖는 배터리팩을 계산한다. 또한 이 툴은 설계된 배터리팩 구성의 사용에 따른 용량 감소 경향을 예측할 수 있다.

• 한국기계가공학회지
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• 제13권6호
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• pp.134-138
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• 2014

Power packs can change energy to hydraulic energy generated by an engine as a tool for use with civil engineering construction equipment. This paper determines which type of power pack meets the standards of construction machinery. A power pack was formulated as a three-dimensional model by using the software CATIA. A modal analysis was conducted using ANSYS Workbench, and the resonance was checked. Next, a harmonic analysis was conducted. The analytical results show that the dynamic stability of the power pack is assured.

• 반도체디스플레이기술학회지
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• 제15권2호
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• pp.20-25
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• 2016

The parallel computer cluster system has been known as the powerful tool to solve a complex physical phenomenon numerically. The numerical analysis of large size of Li-ion battery pack, which has a complex physical phenomenon, requires a large amount of computing time. In this study, the numerical analyses were conducted for comparing the computing efficiency between the single workstation and the parallel cluster system both with multicore CPUs'. The result shows that the parallel cluster system took the time 80 times faster than the single work station for the same battery pack model. The performance of cluster system was increased linearly with more CPU cores being increased.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권4호
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• pp.491-498
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• 2018

The cost evaluation for voyage route planning in an ice-covered sea is one of the major topics among ship owners. Information of the ice properties, such as ice type, concentration of ice, ice thickness, strength of ice, and speed-power relation under ice conditions are important for determining the optimal route in ice and low operational cost perspective. To determine achievable speed at any designated pack ice condition, a model test of resistance, self-propulsion, and overload test in ice and ice-free water were carried out in a KRISO ice tank and towing tank. The available net thrust for ice and an estimation of the ice resistance under any pack ice condition were also performed by I-RES. The in-house code called 'I-RES', which is an ice resistance estimation tool that applies an empirical formula, was modified for the pack ice module in this study. Careful observations of underwater videos of the ice model test made it possible to understand the physical phenomena of underneath of the hull bottom surface and determine the coverage of buoyancy. The clearing resistance of ice can be calculated by subtracting the buoyance and open water resistance form the pre-sawn ice resistance. The model test results in pack ice were compared with the calculation results to obtain a correlation factor among the pack ice resistance, ice concentration, and ship speed. The resulting correlation factors were applied to the calculation results to determine the pack ice resistance under any pack ice condition. The pack ice resistance under the arbitrary pack ice condition could be estimated because software I-RES could control all the ice properties. The available net thrust in ice, which is the over thrust that overcomes the pack ice resistance, will change the speed of a ship according to the bollard pull test results and thruster characteristics (engine & propulsion combination). The attainable speed at a certain ice concentration of pack ice was determined using the interpolation method. This paper reports a procedure to determine the attainable speed in pack ice and the sample calculation using the Araon vessel was performed to confirm the entire process. A more detailed description of the determination of the attainable speed is described. The attainable speed in 1.0 m, 90% pack ice and 540 kPa strength was 13.3 knots.

• 한국수소및신에너지학회논문집
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• 제31권5호
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• pp.489-497
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• 2020

The Li-ion battery is considered to be one of the potential power sources for electric vehicles. In fact, the efficiency, reliability, and cycle life of Li-ion batteries are highly influenced by their thermal conditions. Therefore, a novel thermal management system is highly required to simultaneously achieve high performance and long life of the battery pack. Basically, thermal modeling is a key issue for the novel thermal management of Li-ion battery systems. In this paper, as a basic study for battery thermal modeling, temperature distributions inside the simple Li-ion battery pack (comprises of nine 18650 Li-ion batteries) under a 1C discharging condition were investigated using measurement and computational fluid dynamics (CFD) simulation approaches. The heat flux boundary conditions of battery cells for the CFD thermal analysis of battery pack were provided by the measurement of single battery cell temperature. The temperature distribution inside the battery pack were compared at six monitoring locations. Results show that the accurate estimation of heat flux at the surface of single cylindrical battery is paramount to the prediction of temperature distributions inside the Li-ion battery under various discharging conditions (C-rates). It is considered that the research approach for the estimation of temperature distribution used in this study can be used as a basic tool to understand the thermal behavior of Li-ion battery pack for the construction of effective battery thermal management systems.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.289-289
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• 2009

The series hybrid propulsion system in bimodal tram consists of CNG engine, generator, inverter, motor and battery as main components. Among them, battery is very important thing to make a hybrid bimodal tram more efficient in driving. Battery pack is composed of 168 LPB(lithium polymer battery) cells, 650Vdc-300A. LPB should be treated with a good consideration in both temperature and overvoltage. This paper had analyzed and investigated the thermal flow and distribution of LPB module(l4 LPB cells) and Pack in simulated environments by commercial thermal analysis tool.

• 기술혁신학회지
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• 제7권2호
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• pp.413-439
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• 2004

There are many new technologies developed these days and the companies try to assess their technologies in order to either get financial supports or verify how valuable they are. However, since not only so many innovative technologies have been developed, but also the areas are very diverse, it becomes really difficult to value the technologies by the conservative technology valuation systems. Especially, in the energy technology area, it is much harder because energy technology is mainly used for public purposes and there have not been many experiences of valuing technologies. In this paper, the objective and systematic technology valuation system tool for energy technology will be suggested and investigated.

• 한국엔터테인먼트산업학회논문지
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• 제15권7호
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• pp.271-280
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• 2021

본 연구는 죽초액을 함유한 폼클렌징과 토너, 팩 사용에 따른 여드름 피부상태 개선을 주·객관적 평가를 통해 검증하고자 하였다. 연구 대상은 한국형 여드름 중등도 시스템에 의한 2등급 이상의 여드름 피부 해당자로 광주·전라 지역 고등학교 남·여학생 20명을 선정하였다. 실험 진행을 위해 대상자를 죽초액 함유 폼클렌징, 토너, 팩 사용군(실험군) 10명, 죽초액 비함유 폼클렌징, 토너, 팩 사용군(대조군) 10명으로 나누어 12주 동안 각각 폼클렌징과 토너, 팩사용하도록 하였으며, 그 결과는 다음과 같다. 객관적 측정값에 의한 피부개선 효과에서 실험군이 대조군에 비해 이마, 콧등, 왼쪽볼의 모공 감소와 피지 개선 정도가 크게 나타났으며(p<.001), 주관적 평가도구에 의한 피부개선 효과에도 실험군이 대조군에 전반적인 만족도가 높게 나타났다(p<.05, p<.001). 화장품 사용 만족도는 전체 값에서 폼클렌저, 토너, 팩 모두 실험군이 대조군에 비해 높게 나타났으며(p<.01, p<.001), 세부적으로 유용성에서 통계적으로 유의한 차이를 보였다(p<.01, p<.001). 이상의 결과 죽초액은 여드름 피부상태 개선에 효과적인 천연화장품 소재임이 확인되었다.

• 한국자동차공학회논문집
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• 제22권3호
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• pp.179-185
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• 2014

Average temperature and temperature uniformity in a battery cell are the important criteria of the thermal management of the battery pack for hybrid electric vehicles and electric vehicles (HEVs and EVs) because high power with large size cell is used for the battery pack. Thus, liquid cooling system is generally applied for the HEV/EV battery pack. The liquid cooling system is made of multiple cooling plates with coolant flow paths. The cooling plates are inserted between the battery cells to reject the heat from batteries to coolant. In this study, the cooling plate with U-shaped coolant flow paths is considered to evaluate the effects of coolant flow condition on the cooling performance of the system. The counter flow and parallel flow set up is compared and the effect of flow rate is evaluated using CFD tool (FLUENT). The number of counter-flows and flow rate are changed and the effect on the cooling performance including average temperature, differential temperature, and standard deviation of temperature are investigated. The results show that the parallel flow has better cooling performance compared with counter flow and it is also found that the coolant flow rate should be chosen with the consideration of trade-off between the cooling performance and pressure drop.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 춘계종합학술대회
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• pp.626-629
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• 2007

동화상 압축 기술과 네트워크의 발달로 빠르게 보급된 디지털 콘텐츠는 불법복제와 인터넷을 통한 유포로 인해 지적 재산권 보호의 필요성이 대두되었다. 이에 다양한 표준화 단체들과 콘텐츠 제공업체들이 디지털 콘텐츠 보호를 위한 솔루션을 개발하였고 이 과정에서 서로 다른 독자적인 솔루션 개발로 인하여 이기종 디지털 콘텐츠 보호 시스템간의 상호운용성 결여라는 문제에 봉착하게 되었다. 이 문제를 해결하기 위해 MPEC(Moving Picture Experts Group) 단체에서 이기종간의 상호운용 가능한 IPMP(Intellectual property Management and Protection) 기술에 대한 표준화를 진행하였으나 만족할 정도의 기능을 제시하지 못하면서 이에 대한 대안으로 DMP(Digital Media Rroject) 표준이 제시되었다. 이에 본 논문에서는 MPEG의 IPMP 표준을 분석하고 이를 보완하기 위해 DMP의 툴팩(ToolPack)을 사용하여 이기종간의 상호운용성 확보가 가능한 디지털 콘텐츠를 보호 시스템을 설계 및 구현하였다.