• 전기학회논문지
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• 제59권3호
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• pp.569-574
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• 2010

The full bridge converter have been used for high power system that is needed to switch the big current. So, EMI and stability problem is occurred. The Soft switching method is the solution to solve the above problem, But implementation of soft switching(ZVS: Zero Voltage Switching) is so complicate and expensive because of the DSP MCU and shift circuit. In this paper, we introduce the technical method for driving circuit of ZVS full bridge converter with 1st order delay circuit and logic elements. The realization of this method is so simple and cheap. The effectiveness of the proposed circuit is verified by experimental results.

• 한국측량학회지
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• 제25권4호
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• pp.319-325
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• 2007

GPS를 이용한 상대측위에 있어서 기선의 길이가 길어질수록 측위지점 사이의 상관관계 저하로 인하여 전리층 지연 효과와 같은 오차가 관측치내에 존재하는 문제가 여전히 남아있다. 본 연구에서는 중기선 이상의 상대측위에서 가장 큰 오차요인으로 알려져 있는 전리층 지연 효과를 통계적 모델을 이용하여 모델링하고, 이론적 경험적으로 가장 좋다고 알려져 있는 LAMBDA방법을 이용하여 모호정수를 결정하였다. 상시관측소데이터를 이용하여 통계적 모델을 경험적으로 Gauss-Markov 1차를 결정하였으며, 모델 파라미터인 상관시간(correlation time) 및 모델의 분산을 산출하였다. 최종적으로 개발된 알고리즘의 적용 및 정확도 분석을 위하여 상용소프트웨어 및 Bernese와 비교하였다.

• 전자공학회논문지S
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• 제35S권5호
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• pp.1-10
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• 1998

Satellite communication is getting more important in the coming 21st century because of its wide areas sevice capability, ease of access, and fast channel establishment. As such, satellite communication networks will be the basis of the global communication system in cooperation with the ground ATM networks. In this paper, we consider an efficient transmission methodology of ATM cells over the satellite communication channel. We first analyze possible bottlenecks and performance deterioration factors in the case, and then propose an enhanced cell trasmission mechanism. In order to use satellite channel for ATM cell transmission, the application of complicated channel coding is inevitable. However, the forwared error control such as convolutional encoding brings forth burst errors, which calls for the application of some kind of interleaving mechanism to randomize the burst errors at the receiver. Another aspect which should b econsidered in satellite communication system is the inherent transmission delay, which can be very considered in satellite communication system is te inherent transmission delay, which can be very critical to the delay-sensitive ATM traffic. Therefore, we propose that the processing delay at the block interleaving stage should be controlled propose a variable-size block interleaving mechanism which utilizes the predicted transmission delay for each traffic in the queues of the transmitter. According to the computer simulation, the proposed mechanism could improve the overall performance by drastically reducing the ATM cell drop rate owing to the excessive transmission delay.

• 제어로봇시스템학회논문지
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• 제16권11호
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• pp.1096-1103
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• 2010

This paper proposes CDC (Continuous Damping Control) algorithm and verifies in multi-body dynamic vehicle. In order to distinguish a road profile on driving, waviness calculated by the filtered vertical-accelerations of sprung and unsprung masses is introduced. Sky-hook control is used at a low waviness road and constant damping level control is used at a high waviness road, where the hard damping level is determined by waviness, roll rate, acceleration, and deceleration. The damping levels of ride, anti-roll, anti-squat, and anti-dive modules are calculated by tuning parameters which is dependent upon vehicle velocity. Therefore this high tunable algorithm is useful to improve the ride and handling performance under various driving conditions. In the simulations, tire and dampers are modelled by SWIFT (Short Wavelength Intermediate Frequency Tire) model and 1st order delay model, and results are compared with conventional damper's.

• 한국임상약학회지
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• 제21권2호
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• pp.57-65
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• 2011

Incretin hormones such as glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide delay gastric emptying, increasing satiety, and enhance insulin secretion. Two new classes of treatments related to incretin hormones for the management of type 2 diabetes mellitus have emerged: GLP-1 receptor agonists (e.g., exenatide, liraglutide) and the dipeptidyl peptidase-4 (DPP-4) inhibitors (e.g., sitagliptin, saxagliptin, vildagliptin, alogliptin), which prevent the degradation of GLP-1. A MEDLINE search was conducted in order to evaluate the efficacy and safety of incretin-based therapies and publications were reviewed. Data from clinical trials indicated incretin-based treatment showed clinically significant reductions in hemoglobin A1c with low risk of hypoglycemia. Weight reductions were observed with GLP-1 receptor agonists where as DPP-4 inhibitors are weight neutral.

• 화약ㆍ발파
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• 제8권2호
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• pp.3-17
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• 1990

The Caustious blasting have often increased Complaints of ground Vibration and Sound when the Wire-Tunnel Constructed in Pusan. In order to prevent the influence to housing structure, it was necessary to predict blasting-Induced Vibration and Sound. The Suveyer determined the Burden and spacing of Drill holes, minimum delay charges within a allowable Vibration and Sound Level. Tunnel drilling and Ignition patterns are made as follows; No. 1 Tunel (Stable rock, hard rock) No.2 Tunnel (Instable plastic rock; wethered rock) and other Tunnels (Instable rock). The result of 1st testing blasting of No. 1 Tunnel was recorded Under allowable Vibration Level but sound was over 75 Db of allowable value. So Tunnel drilling pattern was amended with 52 Non-charg holes to reduce the blast-sound. The other pattern had no need to amend.

• 대한전자공학회논문지SD
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• 제48권2호
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• pp.7-13
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• 2011

본 논문에서는 디지털 위상고정루프(All-digital PLL)를 구성하는 핵심 블록인 시간-디지털 변환기(Time-to-Digital Converter)를 제안하고 구현하였다. 본 연구에서는 게이티드 링 오실레이터 시간-디지털 변환기(GRO-TDC)의 기본 구조에 버니어 지연단(VDL)을 이용하여 다중 위상을 얻음으로써 보다 높은 해상도를 얻을 수 있는 구조를 제안하였다. 게이티드 링 오실레이터(GRO)는 총 7개의 지연셀을 사용하였고, 버니어 지연단(VDL) 3단을 이용하여 총 21개의 다중 위상을 사용하여 시간-디지털 변환기(TDC)를 설계하였다. 제안한 회로는 $0.13{\mu}m$ 1P-6M CMOS 공정을 사용하여 설계 및 구현하였다. 측정결과, 제안한 시간-디지털 변환기(TDC)의 최대 입력 주파수는 100MHz이고, 해상도는 26ps로 측정되었으며, 출력은 8-비트이며, 검출이 가능한 최대 위상 차이는 5ns의 위상 차이까지 검출이 가능하였다. 전력 소비는 측정된 Enable 신호의 크기에 따라 최소 8.4mW에서 최대 12.7mW로 측정되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.361-364
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• 2002

In this paper, we propose a new method to deal with the optimized auto-tuning for the PID controller which is used to the process-control in various fields. First of all, in this method, 1st order delay system with dead time which is modelled from the unit step response of the system is $Pad'{e}$-approximated, then initial values are determined by the Ziegler-Nickels method. So deciding binary strings of parents generation using by the fitness values of genetic algorithms, we perform selection, crossover and mutation to generate the descendant generation. The advantage of this method is better than the Ziegler-Nickels method in characteristic of output, and has extent of applying without limit of K, L, T parameters.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.848-850
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• 1997

A control method of UPFC (Unified Power Flow Controller) to reduce low frequency oscillation is proposed. UPFC is modelled by voltage source, which magnitude and phase angle can be controlled. Because there needs some time to change to desired value, d-axis voltage and Q-axis voltage is modeled by 1st order delay. LQG(Linear Quadratic Gaussian) is used. It is shown that low frequency can be damped by control of UPFC effectively.

• 한국조명전기설비학회지:조명전기설비
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• 제13권2호
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• pp.195-195
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• 1999

This paper is Proposed a new method to deal with the optimized auto-tuning for the PID controller which is used to the process-control in various fields. First of all, in this method, 1st order delay system with dead time which is modelled from the unit step response of the system is Pade-approximated, then initial values are determined by the Ziegler-Nickels method. So we can find the parameters of PID controller so as to minimize the fuzzy criterion function which includes the maximum overshoot, damping ratio, rising time and settling time. Finally, after studying the parameters of PID controller by Backpropagation of Neural-Network, when we give new K, L, T values to Neural-Network, the optimized parameter of PID controller is found by Neural-Network Program.