• 한국인터넷방송통신학회논문지
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• 제14권4호
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• pp.71-76
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• 2014

본 논문에서는 고차 QAM 시스템에서 Flag를 가지는 SMMA 적응 블라인드 등화 알고리즘을 제안한다. SMMA는 MMA를 변형하여 다중 contour를 적용함으로써 특성 향상을 얻었으나 여전히 불일치 문제로 인해 정상상태에서의 잔류 오차가 크다는 한계를 가지고 있다. 이러한 정상상태에서의 잔류 오차를 크게 줄이기 위해 우리는 SMMA와 결정지향 알고리즘으로 부터 얻어진 '1' 또는 '0'의 이진 Flag에 의해 제어되는 SMMA를 제안하고, 이 알고리즘에 대한 성능을 분석하였다. 컴퓨터 모의실험을 통하여 제안한 알고리즘이 MMA나 SMMA에 비해 정상상태에서의 잔류 심볼간 간섭과 잔류 오차등에서 크게 향상된 성능을 가짐을 확인하였다.

• 소성∙가공
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• 제11권2호
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• pp.138-146
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• 2002

This paper is concerned with the simulation-based process design method involved non-steady state problem of tension levelling considering the elasto-plastic hardening behavior of a metallic strip by a commercial code ABAQUS/Standard. The tension levelling process is peformed to elongate the strip plastically in combination of tensile and bending strain by a controlled manner so that all longitudinal fibers in the strip have an approximately equal amount of length and undesirable strip shapes are corrected to the flat share. Objectives of this paper are the development of a general method for the design of a tension leveller by a finite element method and parameter studies for the deisgn variables such as the applied tension, the roll intermash includes the determination of the steady state using the simple unit of the tension levelling line and the effect of the finite element mesh size on the amount and distribution of the strain calculated. The analysis provides the information about the intermesh effect on the amount and final shapes of the strip and distribution of the strain in order to determine the amount elongation for correction of the irregular share.

• 한국지능시스템학회논문지
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• 제25권3호
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• pp.254-259
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• 2015

본 논문은 BCI(Brain Computer Interface)기반의 정상상태시각유발전위(SSVEP : Steady-State Visual Evoked Potential)를 사용하여 무선 로봇 제어를 위한 시스템을 제안하였다. CPSD(Cross Power Spectral Density)를 사용하여 전극의 신호를 분석하였다. 또한 분류를 위해서 LDA(Linear Discriminant Analysis)와 SVM(Support Vector Machine)을 사용하였다. 그 결과 피험자들의 평균 분류율은 약 70%로 나타났다. 로봇제어의 경우 뇌파의 값을 분류하여 나타난 결과 값으로 로봇이 움직일 수 있도록 구현하였고, 블루투스 통신을 이용하여 로봇제어를 수행하였다.

• 한국생산제조학회지
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• 제22권3호
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• pp.364-371
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• 2013

Because of the increases in international oil prices and the level of global warming, the automotive industry has much interest in developing green cars with high fuel efficiencies. In addition, researchers in Korea are actively responding to high oil prices and $CO_2$ emission regulations in many ways. One example is, the multi-mode hybrid system, which is being studied to improve its performance. Because a multi-mode hybrid system is able to overcome the weaknesses of a system that uses simple planetary gears, excellent fuel efficiency and driving performances are the key features of the system. This paper analyzes the driving performance of the power-train system of GM-2MT70, which consists of one engine, two electric motors, one simple planetary gear, one double planetary gear, two clutches, and two brakes. The driving performance of the system's steady state is analyzed using performance modeling. The dynamic performance is analyzed using Matlab Simulink.

• 정보학연구
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• 제1권2호
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• pp.39-53
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• 1998

CMA나 MCMA 적응 블라인드 등화 알고리즘은 특별한 형태의 신호점을 원하는 신호점로 간주하므로써 완전한 등화에 도달시에도 원래의 신호점과의 불일치로 인한 오차가 불가피하다. 본 논문에서는 축소 신호점 대신에 결정된 원래의 신호점을 이용한 새로운 오차함수를 도입하여 빠른 수렴 속도로 정상상태에 도달하며, 정상상태에서의 오차를 크게 개선한 새로운 적응 블라인드 등화 알고리즘을 제안한다. 컴퓨터 모의실험을 통하여 제안한 알고리즘이 반송파 위상 복원을 가지는 CMA 및 MCMA등과 같은 CMA 계열의 적응 블라인드 등화 알고리즘들에 비해 잔류 심볼간 간섭과 수렴 속도면에서 향상된 성능을 가짐을 확인 하였다.

• Journal of Electrical Engineering and Technology
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• 제7권5호
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• pp.689-697
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• 2012

This paper proposes a new coordinated voltage control scheme between STATCOM (Static Synchronous Compensator) and reactive power compensation devices, such as shunt elements(shunt capacitor and shunt reactor) and ULTC(Under-Load Tap Changer) transformer in a local substation. If STATCOM and reactive power compensators are cooperatively used with well designed control algorithm, the target of the voltage control can be achieved in a suddenly changed power system. Also, keeping reactive power reserve in a STATCOM during steady-state operation is always needed to provide reactive power requirements during emergencies. This paper describes the coordinative voltage control method to keep or control the voltage of power system in an allowable range of steady-state and securing method of momentary reactive power reserve using PSS/E with Python. In the proposed method of this paper, the voltage reference of STATCOM is adjusted to keep the voltage of the most sensitive bus to the change of loads and other reactive power compensators also are settled to supply the reactive power shortage in out range of STATCOM to cope with the change of loads. As the result of simulation, it is possible to keep the load bus voltage in limited range and secure the momentary reactive power reserve in spite of broad load range condition.

• Journal of Power Electronics
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• 제18권5호
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• pp.1398-1408
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• 2018

In order to further improve the steady-state control performance of model predictive torque control (MPTC), a double-vector-based model predictive torque control without a weighting factor is proposed in this paper. The extended voltage vectors synthesized by two basic voltage vectors are used to increase the number of feasible voltage vectors. Therefore, the control precision of the torque and the stator flux along with the steady-state performance can be improved. To avoid testing all of the feasible voltage vectors, the solution of deadbeat torque control is calculated to predict the reference voltage vector. Thus, the candidate voltage vectors, which need to be evaluated by a cost function, can be reduced based on the sector position of the predicted reference voltage vector. Furthermore, a cost function, which only includes a reference voltage tracking error, is designed to eliminate the weighting factor. Moreover, two voltage vectors are applied during one control period, and their durations are calculated based on the principle of reference voltage tracking error minimization. Finally, the proposed method is tested by simulations and experiments.

• Journal of Pharmaceutical Investigation
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• 제26권2호
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• pp.99-103
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• 1996

Effects of glycerin and PEG 400 in donor and receptor solutions upon skin permeation of drug were investigated. Deoxycortisone was used as a model compound. In vitro skin permeation study with freshly excised hairless mouse skin was performed and the steady-state skin permeation rates of the drug were determined in different fractions of glycerin or PEG 400 in donor and receptor solutions. Glycerin in donor solution didn't show any effect on the skin permeation rate of deoxycortisone. However glycerin in receptor solution showed significant effect on the skin permeation rate of the drug. In glycerin, there's a critical concentration for balancing hydration and dehydration of skin. At low concentration, less than 20 %, glycerin showed the enhancement of the flux due to the hydration effect of skin. At high concentration, more than 30 %, glycerin retard the permeation rate which might be due to the dehydration effect on the dermis layer. Since dermis has more water content than the stratum corneum, the steady state skin permeation rates were more influenced when glycerin was in receptor solution than that of in donor solution. PEG 400 aqueous solutions doesn't affect the steady state permeation rate of deoxycortisone significantly.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.2036-2041
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• 2014

In this paper, a thermal model is developed for the bus bar system to predict the temperature variation during the transient time period and to calculate both the steady-state and transient electrical current carrying capacity (ampacity) of bus bar. The bus bar system installed in the power house of Kumaraguru College of Technology, Coimbatore has been considered. Temperature variation predicted in the modelling is validated by observing the current and steady state temperatures in different feeders of the bus bar. Magnetic field of the extreme phases R and B induces more current in the middle phase Y. Hence, the steady state temperature in the phase Y is greater than other two phases. The transient capabilities of the bus bar are illustrated by calculating the variations in the bus bar temperature when it is subjected to a step change in current during the peak hours due to increase in hostel utilities and facilities (5.30 pm to 10.30 pm). The physical and geometrical properties of the bus bar and temperature variation in the bus bar are used to estimate the thermal time constants for common bus bar cross-sections. An analytical expression for the time constant of the bus bar is derived.

• 한국추진공학회지
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• 제8권2호
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• pp.32-38
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• 2004

추진제 주입압력 350 psi (2.41 Mpa) 에서 0.95 lbf (4.2 N) 의 정상상태 공칭추력을 내는 단일액체추진제 하이드라진 로켓엔진(추력기)의 성능검증 프로그램을 통하여 얻어진 연소시험 결과를 분석한다. 성능특성은 정상상태 연소모우드에서 추진제 주입압력 변이(400~50 psi)에 따른 추력 및 온도거동 등으로 검토되며, 추력 및 비추력 성능은 1 lbf급 표준형 로켓엔진의 기준 추력선도 상에서 비교되고 몇몇 특정 압력에서 규준화된다. 데이터 계측 및 자료변환에 대한 실제적인 공학적 접근법도 소개된다.