• 대한전자공학회논문지SD
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• 제47권2호
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• pp.32-39
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• 2010

기존의 셀 특성 분석은 다중 입력 변화를 고려하지 않고 셀 특성 분석을 수행한다. 다중 입력 변화가 시간적 근접성에 따라 게이트 지연 시간에 미치는 영향이 커지면서, 기존의 셀 특성 분석으로는 정확한 게이트 지연 시간을 예측하기가 어려워지게 되었다. 다중 입력 변화의 영향으로 인하여 게이트 지연 시간이 최대 46%까지 차이가 나는 것을 실험을 통하여 확인하였다. 본 논문에서는 다중 입력 변화의 시간적 근접성으로 인한 지연 시간 변화를 고려한 게이트 지연 시간 모델을 제안하였다. 제안된 모델은 Radial Basis Function (RBF)을 이용하여 지연 시간 변화량을 계산한다. 제안된 방법이 다중 입력 변화가 발생하였을 때, 보다 정확하게 게이트 지연 시간을 예측하는 것을 실험결과를 통하여 확인하였다.

• 한국항해학회지
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• 제7권1호
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• pp.1-32
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• 1983

The delay due to congestion has recently attracted widespread attention with the analysis of over-all operation at the port. But, the complexity of the situation is evident in view of the large number of factors which impinge on the considerable end. Queueing theory is applicable to a large scale transportation system which is associated with arrivals of vessels in a large port. The attempt of this paper is to make an extensive analysis of the port transport system and its economic implications from the viewpoint that port is one of the physical distribution facilities and a kind of queueing system which includes ships and cargoes as port customer. By analyzing the real data on the Port of Pusan, it is known that this port can be represented as a set of multi-channel with identical setof Poisson arrival and Erlang service time, and also it is confirmed that the following formula is suitable to calculate the mean delay in this port, namely, $W_4={\frac{\rho}{\lambda(1-\rho)} {\frac{e_N(\rho{\cdot}N)}{D_{N-1}(\rho{\cdot}N)}$ where, ${\lambda}$: mean arrival rate $\mu$: mean servicing rate; N: number of servicing channel; ${\rho}$: utillization rate (${\lambda}/N{\mu}$) $e_N$: the Poisson function Coming to grips with the essentials of the cost of delay due to congestion, a simple ship journey cost model is adopted and the operating profit sensitivity to variation in port time is examined, and for purpose of a future development for port princing service the marginal cost is approximately calculated on the basis of queueing theory.

• 한국통신학회논문지
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• 제37C권11호
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• pp.1104-1111
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• 2012

공중 전술 네트워크는 공대공 또는 공대지 작전에 사용되고 전파 지연이 크다는 특징이 있다. 모든 노드는 TDMA 기반의 브로드캐스팅을 사용하여 데이터를 공유한다. 공중 전술 네트워크에서는 긴 전파 지연으로 인한 충돌 때문에, 브로드캐스팅을 보장하기 위해서는 각 타임 슬롯마다 보호 시간이 필요하다. 그러나 보호 시간의 낭비로 인해 네트워크의 채널 이용률이 크게 저하될 수 있다. 본 논문에서는 송신자 간 거리 정보를 사용하여 보호 시간의 낭비를 줄여 채널 이용률을 향상시키면서 브로드캐스팅을 보장하는 Inter-Transmitter Distance-Based TDMA (ID-TDMA) 기법을 제안한다. 그리고 성능 평가를 통해 ID-TDMA의 효과성을 확인하였다.

• Structural Engineering and Mechanics
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• 제40권3호
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• pp.431-451
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• 2011

Time delay inevitably exists in active control systems, and it may cause the degradation of control efficiency or instability of the systems. So time delay needs to be compensated in control design in order to eliminate its negative effect on control efficiency. Today time delay in linear systems has been more studied and some treating methods had been worked out. However, there are few treating methods for time delay in nonlinear systems. In this paper, an active controller for a nonlinear and hysteretic building structure with time delay is studied. The nonlinear and hysteretic behavior of the system is illustrated by the Bouc-Wen model. By specific transformation and augmentation of state parameters, the motion equation of the system with explicit time delay is transformed into the standard state space representation without any explicit time delay. Then the fourth-order Runge-Kutta method and instantaneous optimal control method are applied to the controller design with time delay. Finally, numerical simulations and comparisons of an eight-story building using the proposed time-delay controller are carried out. Simulation results indicate that the control performance will deteriorate if time delay is not taken into account in the control design. The simulations also prove the proposed time delay controller in this paper can not only effectively compensate time delay to get better control effectiveness, but also work well with both small and large time delay problems.

• 한국전자파학회논문지
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• 제26권2호
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• pp.213-217
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• 2015

본 논문에서는 밴드 패스 필터 및 노치 필터로의 용도 변환이 가능하고, 대역폭 변화가 용이한 새로운 구조의 MWP 필터를 제안하였다. 인접 채널의 단위 시간지연 차이가 50 ps인 $4{\times}2$ 광섬유 지연선로 행렬로 구성된 MWP 필터를 제작하였고, 각 채널의 시간 지연 및 MWP 필터의 주파수 응답 등의 특성을 측정하였다. RF 변조 광 신호의 시간 지연 차이와 계수를 변화시킴으로써 20 GHz와 6.67 GHz의 FSR 변화 특성을 확인하였다.

• Transactions on Control, Automation and Systems Engineering
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• 제2권3호
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• pp.149-156
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• 2000

Time delay observer (TDO), thanks to the time delay control (TDC) concept, requires little knowledge of a plant model, and hence is easy to design, robust to parameter variation and computationally efficient, yet can reconstruct states rather reliable for nonlinear plant. In this paper, we propose an improved version of TDO that solves two problems inherent in TDO as follows: TDO displays large reconstruction errors due to low-frequency uncertainty and has some restrictions on selecting its gains. By introducing a low pass filter and a state associated with it, we obtain an enhanced time delay observer (ETDO). This observer turns out to have smaller reconstruction errors than those of TDO and not to have any restriction on selecting its gains, thereby solving the problems. Through performance comparison by transfer function and simulation, we validate the analysis results of two observers (TDO and ETDO) and evaluate the performances. Finally, through experiments on BLDC motor system, the analysis results are clearly conformed.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.882-886
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• 2005

As the TFT-LCD panels become larger and provide higher resolution, the distributed capacitive and resistive lines induce the propagation delay, reduce the TFT-on time and deteriorate the pixel chargingratio. A number of the compensation methods, like the H-LDC (Horizontal Line Delay Compensation), have been proposed to compensate the propagation delay of the large and high resolution panels [1]. These methods, however, require the comparatively accurate gate propagation delay estimates at each column driver. In this paper, by observing the actual gate and data waveform from 15-inch XGA TFT-LCD panels, we could predict the propagation delay along the row and column line.

• 한국안전학회지
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• 제1권1호
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• pp.33-40
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• 1986

The results from a study on the combustion of the ferrosilicon-miniun delay powder which was examined under the various conditions are as follows. 1. It has been found that in case of these delay powders, decomposition of oxidiging agents occurs first and then reducing agents are oxidized by the gases evolved from the oxidizing agents and by the oxygen in air. Therefore, the main reactions are heterogenous reaction and especially He gas phase plays an important role in combustion reactions of delay Powders. 2. In case the loading pressure is below 100kg per a detonator, the dispresion of burning time is large. 3. Little or no increase in humidity was observed on daily measurement during six month preservation tests. 4. The amperage of electric current for igniting the fuse head has no effect on the burning time of delay conposition itself changed in the detonator.

• 터널과지하공간
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• 제6권3호
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• pp.267-273
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• 1996

The types of eletric detonators manufactured in korea include instantaneous, decisecond and millisecond delays but number of delay intervals are only limited from No. 1 to No. 20 respectively. It is not sufficient to control accurately millisecond time with these detonators in large surface blasting. But nonelectric system detonators with an unlimited delay time are recently obtained. In this paper the effect of delay time of nonelectric detonator on the level of vibration in surface blasting was studied. A total of 169 data were recorded in the studied area. Blast point-to-measuring point distances ranged from 25 to 100 meter, where charge weight was 1.26 kg per delay.

• 한국통신학회논문지
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• 제32권1B호
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• pp.53-60
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• 2007

본 연구에서는 Diffserv 기반의 네트워크, 특히 그 중에서도 트리구조를 가지는 네트워크에서의 지연시간에 대해서 연구하였다. 이러한 네트워크에서의 지연시간 최대치를 구하는 수식을 구하였고, 특히 기존에 알려진 바와는 달리 트리구조의 네트워크에서는 네트워크 utilization과는 상관없이 최대치가 항상 존재함을 보였다. 지연시간 최대치의 특성은 다음과 같이 표현된다. 네트워크 utilization이 큰 경우 네트워크내의 최대 hop count의 제곱에 비례하며, 네트워크 utilization이 작은 경우는 최대 hop count에 비례한다. 이러한 결과를 바탕으로 실제 Metro Ethernet Network과 같은 대규모 네트워크의 경우에서 DiffServ를 이용하여 실시간 트래픽 전송이 가능하다는 것을 보였다.