• 한국군사과학기술학회지
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• 제19권1호
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• pp.26-34
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• 2016

Military devices and systems powered by batteries need to operate at extreme temperature and estimate the available capacity of the battery at different temperature conditions. However, accurate estimation of battery capacity is challenging due to the temperature-sensitive nature of electrochemical energy storage. In this paper, Peukert's equation with temperature factor is derived, and methods for estimating the absolute capacity of lithium-polymer battery and the state-of-charge(SOC) with respect to varying currents and temperatures are presented. The proposed estimation method is experimentally verified under three different discharge currents(0.5 A, 1 A, 3 A) and six different temperatures ranging from -30 to 45 deg. C. The results show the proposed method reduces the Peukert's estimation error by up to 30 % under or at extreme condition.

• 한국항공운항학회지
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• 제31권2호
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• pp.55-65
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• 2023

Due to extreme urbanization, ground transportation in the city center is saturated, and problems such as the lack of expansion infrastructure and traffic congestion increase social costs. To solve this problem, a 3D mobility platform, Urban Air Mobility (UAM), has emerged as a new alternative. A vertiport is a physical space that conducts a similar role to an airport terminal. Vertiport consists of take-off and landing facilities (TLOF, Touchdown and Lift-Off area), space for boarding and disembarking from UAM aircraft (gates), taxiways, and passenger terminals. The type of vertiport (structure, number of facilities) and concept of operations are key variables that determine the number of UAM aircraft that can be accommodated per hour. In this study, a capacity calculation method was presented using an optimization technique (Deterministic Integer Linear Programming). The absolute capacity of the vertiport was calculated using an optimization technique, and a sensitivity analysis was also performed.

• 유기물자원화
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• 제24권2호
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• pp.31-39
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• 2016

저수조는 유입/유출량의 시간적인 편차 때문에 필요하다. 저수조 용량 산정하기 위해서 공급(예, 강수) 누적 량과 요구(예, 관수) 누적 량의 차이를 사용한다. (-)와 (+)영역의 상관없이 누적 량 차의 절댓값 최대치가 되었을 때 용량의 산정이 이루어진다. 본 논문에서는, 온실 시설물의 강수와 관수를 이용하여 비선형적인 공급이나 요구량에서도 이를 적용하여 용량을 산정하였고, 비선형적인 변화가 커졌을 시에도 적용 할 수 있음을 증명하였다. 그리고 모니터링에 대한 시간 간격이 작아짐에 따라서, 저수조 용량이 증가되며, 강수량의 경우에는 약 10일을 변곡점으로 증가폭이 감소됨을 보인다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권6호
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• pp.2554-2575
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• 2020

Data hiding technology hides secret information into the carrier, so that when the carrier is transmitted over network, it will not attract any malicious attention. Using data compression, it is possible to reduce the data size into a small compressed code, which can effectively reduce the time when transmitting compressed code on the network. In this paper, the main objective is to effectively combine these two technologies. We designed a data hiding scheme based on two techniques which are turtle-shell information hiding scheme and absolute moment block truncation coding. The experimental results showed that the proposed scheme provided higher embedding capacity and better image quality than other hiding schemes which were based on absolute moment block truncation coding.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.581-586
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• 2002

Addition of steel fiber to shotcrete is to improve the brittleness of concrete. Quality of steel fiber reinforced shotcrete can be evaluated by quantitive analysis of toughness characteristics after cracking. The toughness characteristics can be expressed by absolute value of energy absorption capacity, non-dimensional toughness index related to the energy absorption capacity, and equivalent flexural strength at arbitrary deflection. In this study, merits and demerits of flexural toughness by RTA round panel of Australia and other specifications have been analyzed.

• 한국지진공학회논문집
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• 제8권3호
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• pp.33-42
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• 2004

비선형시스템을 등가의 선형시스템으로 치환하는 것은 해석이 간단하다는 매우 중요한 장점을 제공하지만 구조물의 실제 비선형거동을 정확하게 모델링하지 못하기 때문에 능력스펙트럼법의 정확도는 정확한 등가주기와 등가감쇠비의 산정과 구해진 등가감쇠비에 따른 탄성응답스펙트럼의 수정방법과 그에 따른 요구곡선의 산정에 영향을 받는다. 본 논문에서는 요구곡선의 산정방법에 따른 능력스펙트럼법의 정확성을 분석하였다. 이를 위해 ATC-40과 Euro Code에서 제안한 감소 계수 등의 유효성을 평가하였다. Newmark와 Hall의 수정계수에 기초로 한 ATC-40에서 주어진 감소 계수에 의해 구해진 가속도 응답에 비해 Euro Code에서 주어진 감소 계수를 이용하여 구한 가속도 응답이 실제 평균 응답에 보다 유사함을 알 수 있었다. 그리고 유사가속도 응답을 이용한 방법과 절대가속도 응답을 이용한 방법을 이용하여 요구곡선을 산정하여 능력스펙트럼법의 정확성을 검증해 보았다. 절대가속도 응답을 이용한 결과가 전반적으로 유사가속도 응답을 이용한 결과에 비해 커짐을 알 수 있었고, 능력스펙트럼법이 전반적으로 응답을 과소평가하는 경향이 있어서 이러한 큰 값을 주는 것이 좀 더 정확한 결과를 줌을 알 수 있었다. 하지만 탄성 최대 강도에 대한 항복 강도의 비가 커질수록 그리고 항복 후 강성비가 커질수록 이러한 결과의 차이는 거의 없어짐을 알 수 있었다.

• 수산해양교육연구
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• 제26권5호
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• pp.1083-1089
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• 2014

The aims of this study are to find out the possibility of the charcoal as a desiccant. The only humidity control under high temperature and high humidity environment can be provided to the thermal comfort at indoor environment. Functionality of charcoal is known to be deodorization, antiseptic effect, filtering effect and humidity control. But research related to humidity control in the country not yet. Thus, the dehumidification capacity of the charcoal experimental results to see the results were as follows : 1) Entering the experimental humidification is 148.02 g/h, 161.05 g/h and 243.2 g/h when air velocity was changed 1.5 m/s, 1.7 m/s and 2.0 m/s. 2) When the basis weight of the charcoal 2.0 m/s air velocity to obtain the largest number of adsorption capacity. 3) Dru bulb temperature and dew point temperature ware measured at front and rear of the charcoal. Absolute humidity is calculated from the measured Dry bulb temperature and dew point temperature. The quantity of dehumidification is calculated from absolute humidity is the largest 129.6 g/h at the air velocity 2.0 m/s.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.25-32
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• 1998

Most recent seismic design codes include Response Modification Factor(RMF) for determining equivalent lateral forces. The RMF is used to reduce the linear elastic design spectrum to account for the energy dissipation capacity, overstrength and damping of the structure. In this study the RMF is defined as the ratio of the absolute maximum linear elastic base shear to the absolute maximum nonlinear base shear of a structure subject to the same earthquake accelerogram. This study investigates the effect of hysteretic model, as well as target ductility ratio and natural period on duct based RMF using nonlinear dynamic analyses of the SDOF systems. Special emphasis is given to the effects of the hysteretic characteristics such as strength deterioration and stiffness degradation. Results indicate that RMFs are dependent on ductility, period and hysteretic model.

• International Journal of Advanced Culture Technology
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• 제11권3호
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• pp.310-314
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• 2023

The purpose of this study is to predict the remaining capacity of lithium-ion batteries and evaluate their performance using five artificial intelligence models, including linear regression analysis, decision tree, random forest, neural network, and ensemble model. We is in the study, measured Excel data from the CS2 lithium-ion battery was used, and the prediction accuracy of the model was measured using evaluation indicators such as mean square error, mean absolute error, coefficient of determination, and root mean square error. As a result of this study, the Root Mean Square Error(RMSE) of the linear regression model was 0.045, the decision tree model was 0.038, the random forest model was 0.034, the neural network model was 0.032, and the ensemble model was 0.030. The ensemble model had the best prediction performance, with the neural network model taking second place. The decision tree model and random forest model also performed quite well, and the linear regression model showed poor prediction performance compared to other models. Therefore, through this study, ensemble models and neural network models are most suitable for predicting the remaining capacity of lithium-ion batteries, and decision tree and random forest models also showed good performance. Linear regression models showed relatively poor predictive performance. Therefore, it was concluded that it is appropriate to prioritize ensemble models and neural network models in order to improve the efficiency of battery management and energy systems.

• 수산해양기술연구
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• 제48권1호
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• pp.29-39
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• 2012

Currently, environment-friendly and sustainable fisheries are one of the major issues among fisheries authorities. A variety of alternative management policies and projects are going on to enhance fisheries management systems and fishery resources such as a TAC management program and a VDS (Vessel Day Scheme) management scheme for distant water fishing nations in Western and Central Pacific Fisheries Commission (WCPFC) convention area. These kinds of efforts among fisheries management authorities are aimed at limiting fishing capacity or fishing power. In terms of fisheries management, Fishing capacity and fishing power have increased the importance of the impact on a fishery and level of the resources. Increased fishing capacity and fishing power have caused not only depletion of fisheries resource, but also additional fishing cost. therefore, there is a clear need for authorities to manage fishing capacity and fishing power. It is also help ensure the conservation and sustainability of the fishery resources. Because of lack of data, absolute fishing power is difficulty to measure. The notion of relative fishing power is frequently used. In this study, relative fishing power was assessed using Mastuda (1991) method for fishing power index. The raw data for assessment was based on fishermen's logbook data from sampled fishing vessels in coastal snow crab gillnet fishery. Data Envelopment Analysis (DEA) method was used to assess fishing capacity. DEA is a linear programming methodology to measure the efficiency of a set of entities called Decision-Making Units (DMUs). It was recommended by FAO for assessing capacity in fisheries.