• Explosives and Blasting
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• v.27 no.1
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• pp.38-46
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• 2009

Recently, as a reduction method of vibration and noise, an electronic detonation which has an accuracy of time and a freedom of input delay time was introduced. A waveform composition program can determine a delay time and accomplish simulation under environment similar to real blast using a delay time. In this study, optimum delay time which controls vibration is obtained and real measurement vibration level is estimated by a waveform composition program.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.2
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• pp.129-139
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• 2006

When blasting by imposing the time difference between two adjacent charge holes, the mutual interference phenomenon occurs depending the feature of blast. This interference phenomenon of blast amplifies or compensates the blast-induced vibration depending on the overlapping mechanism. Thus, this experiment aims at finding out the optimum delay time by measuring the blast vibration data from the single hole blast during the blasting test and composing each blasting waveform, and at proving the its efficiency by applying the composition delay time in the entire cross section. The experiment showed that the blasting-induced vibration was reduced by endowing an optimum delay time of electronic detonator appropriate to the rock quality of construction site compared to the typical delay time (20, 25ms) of existing detonator (non-electric and electric detonator). From these results, the excavation efficiency using blasting could be enhanced..

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.3
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• pp.199-203
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• 2011

The wireless sensor network (WSN) based on ad hoc network is applied to vehicle parking guide system without parking guide man at area or building with large scale of parking lots. The optimum number of cluster heads was derived for getting the minimum power consumption as well as time delay. Through the theoretical analysis of power consumption and time delay with the number of cluster heads in wireless sensor network, it was found that there exists the minimum point in the variation of power consumption and time delay according to the number of cluster heads.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.438-445
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• 2007

In this paper, we consider the problem of optimum selection of quality-of-service(QoS) classes in interworking between the networks in a next-generation-network(NGN) environment. After introducing the delay-cost and loss-cost characteristics, we discuss the time-invariant(TI) and time-variant(TV) scenarios. For the TI case, we show that under nearly lossless transmission condition, each network can make its own optimization regardless of other networks. For the TV case, we present sufficient conditions under which the optimum QoS class of each network can be considered fixed with respect to time without considerable degradation in the optimization target. Therefore, under the conditions presented in this paper, the QoS of a flow in each network can be determined solely by considering the characteristics of that network and this QoS class can be held fixed during the flow period.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.2
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• pp.177-184
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• 2008

In this study, in order to reduce appeals regarding vibration and noise from blasts, the optimum delay-time of the electronic detonator, which can minimize blast vibration, is found through blast-waveform composition and blasting simulation, and we have developed the full-face Sequential Blasting Method based on the studies of damping properties of full-face section blasting. The optimum delay-time of the electronic detonator and Full-face Sequential Blasting Method using electronic detonator was applied to the Gyeongbu high-speed railway construction site to test the feasibility of this method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.10
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• pp.916-922
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• 2008

AC PDP with MgO protective layer coated with the optimum evaporation rate of $5{\AA}/s$ can generate more enhanced efficiency through the vacuum in-line sealing process. However, the optimized process conditions still require the optimum driving scheme on the ramp-up and ramp-down slope of the reset waveform for enhancing the efficiency. In this paper, for the in-situ vacuum sealed PDP with the optimum evaporation rate of MgO protective layer, the address delay time was investigated with various slopes of ramp waveform during a reset ramp-up and ramp-down period. In this study, the minimum statistical delay time was obtained at the ramp-up rate of $6.0 V/{\mu}s$ and the ramp-down rate of $0.7 V/{\mu}s$ of the reset waveform.

• Structural Engineering and Mechanics
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• v.1 no.1
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• pp.119-135
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• 1993

The paper presents a generalized optimal active control algorithm for earthquake-resistant structures. The study included the weighting matrix configuration, stability, and time-delays for achieving control effectiveness and optimum solution. The sensitivity of various time-delays in the optimal solution is investigated for which the stability regions are determined. A simplified method for reducing the influence of time-delay on dynamic response is proposed. Numerical examples illustrate that the proposed optimal control algorithm is advantageous over others currently in vogue. Its feedback control law is independent of the time increment, and its weighting matrix can be flexibly selected and adjusted at any time during the operation of the control system. The examples also show that the weighting matrix based on pole placement approach is superior to other weighting matrix configurations for its self-adjustable control effectiveness. Using the time-delay correction method can significantly reduce the influence of time-delays on both structural response and required control force.

• Journal of Korean Society of Transportation
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• v.10 no.3
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• pp.7-20
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• 1992

The common cycle time for the linded signals is usually determined for the critical intersecion, just because the cpacity of a signalized intersection depends on the cycle time. This may not be optimal since the interactions between the flow and the spatial structure of the route or the area are disregarded in this case. It is common to separate the total delay incurred at signals into two parts, a deterministic or uniform delay and a stochastic or random delay. The deterministic delays and the stochastic delays on the artery particularly related to signal cycle time. For this purpose a microscopic simulation technique is used to evaluate deterministic delays, and a macroscopic simulation technique based on the principles of Markov chains is used to evaluate stochastic delays with over flow queue. As a result of investigating the relations between deterministic delays and cycle time in the various circumstances of spacing of signals and traffic volume. As for stochastic delays the resalts of comparisons of the macroscopic simulation and Newell's approximation with the microscopic simulation indicate that the former is valid for the degree of saturation less than 0.95 and the latter is for that above 0.95. Newell's argument that the total stochastic delay on an arterial is dominated by that at or caused by critical intersection is certified by the simulation experiments. The comprehensive analyses of the values of optimal cycle time with various conditions lead to a model. The cycle time determined by this model shows to be approximately 70% of that calculated by Webster's.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.1
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• pp.24-32
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• 2003

The PID controller has been widely used in industrial applications due to its simple structure and robustness. Even if it is initially well tuned, the PID controller must be retuned to maintain acceptable performance when there are system parameter changes due to the change of operation conditions. In this paper, a self-tuning control scheme which comprises a parameter estimator, a NN-based rule emulator and a PID controller is proposed, which can cope with changing environments. This method involves combining neural networks and real-coded genetic algorithms(RCGAs) with conventional approaches to provide a stable and satisfactory response. A RCGA-based parameter estimation method is first described to obtain the first-order with time delay model from over-damped high-order systems. Then, a set of optimum PID parameters are calculated based on the estimated model such that they cover the entire spectrum of system operations and an optimum tuning rule is trained with a BP-based neural network. A set of simulation works on systems with time delay are carried out to demonstrate the effectiveness of the proposed method.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.11
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• pp.1-8
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• 2000

In this paper, the dependence of interconnect line-induced delay time on the size of CMOSFET gate width is characterized. In case of capacitance dominant interconnect line, the total delay time decreases as transistor size increases. However, there exists a transistor size for minimum total delay time when both of resistance and capacitance of interconnect line become larger than those of transistor. The optimum transistor size for minimum total delay time is obtained using an analytic equation and the experimental results showed good agreement with the calculation.