• Journal of the military operations research society of Korea
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• v.2 no.1
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• pp.185-194
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• 1976

A terminal response time analysis for a general class of terminals-to-computer subsystem is presented in this paper. On the point of the front view, it should be considered for R.O.K. Military Defense to set up the communication network in order to facilitate for the currency of the information and the data communication system. The model used to study is based on the advanced data communications system in which terminals are connected to Terminal Control Units(TCU) that are in turn connected to local Front-End Processor(FEP). The line control procedures used to interface a TCU and an FEP may be half-duplex Binary Synchronous Communication(BSC), half-duplex Synchronous Data Link Control(SDLC), or full-duplex SLDC. This paper will contribute to facilitate the initial phase of system design and configuration for the Military Defense Communication Network System in future.

• Journal of the Korea Society for Simulation
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• v.9 no.4
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• pp.67-75
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• 2000

Often system analysts are interested in the estimation of percentile for system performance. For instance, in PERT network system, the percentile that the project. Typically the control variate method is used to reduce the variability of mean response using the correlation between the response and the control variates with a little additional cost during the course of simulation. In the same spirit, we apply this method to estimate the percentile of project completion time in PERT system, and evaluate the efficiency of the controlled estimator for its percentile.1 Simulation results indicate that the controlled estimators are more effective in reducing the variances of estimators than the simple estimators, however those tend to a little underestimate the percentiles for some critical values. We need more simulation experiments to examine such a kind of bias problem. We expect this research presents a step forward in the area of variance reduction techniques of stochastic simulation.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.105-108
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• 2000

Many control techniques have been proposed in order to improve the control performance of discrete-time domain control system. In the position control system using a DC servo motor as a driver, the response-characteristic of system is controlled by the PID controller. In the PID control system, the transient response characteristic is more increased and settling time gets longer if gains of PID controller are unsuitable. In this paper, therefore, a expended PID control system is constructed by inserting a pre-compensator at output terminal of PID controller. It is implemented by using the double layers neural network. Form the results of computer simulation in the proposed control algorithm, its usefulness is verified.

• The Transactions of the Korea Information Processing Society
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• v.7 no.7
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• pp.2161-2168
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• 2000

Since most of the existing web cache structures are static, they cannot support the dynamic request change of he current WWW users well. Users re generally using multiple programs in several different windows with rapid preference change within a relatively short period of time. We develop a network-path based algorithm. It organizes a cache according to the network path of the requested URLs and build a network cache farm where caches are logically connected with each other and each cache has its own preference over certain network paths. The algorithm has been implemented and tested in a real site. The performance results show that the new algorithm outperforms the existing static algorithms in the hit ratio and response time dramatically.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.4
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• pp.750-769
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• 2015

The geometry of engineering systems affects their performances. For this reason, the shape of engineering systems needs to be optimized in the initial design stage. However, engineering system design problems consist of multi-objective optimization and the performance analysis using commercial code or numerical analysis is generally time-consuming. To solve these problems, many engineers perform the optimization using the approximation model (response surface). The Response Surface Method (RSM) is generally used to predict the system performance in engineering research field, but RSM presents some prediction errors for highly nonlinear systems. The major objective of this research is to establish an optimal design method for multi-objective problems and confirm its applicability. The proposed process is composed of three parts: definition of geometry, generation of response surface, and optimization process. To reduce the time for performance analysis and minimize the prediction errors, the approximation model is generated using the Backpropagation Artificial Neural Network (BPANN) which is considered as Neuro-Response Surface Method (NRSM). The optimization is done for the generated response surface by non-dominated sorting genetic algorithm-II (NSGA-II). Through case studies of marine system and ship structure (substructure of floating offshore wind turbine considering hydrodynamics performances and bulk carrier bottom stiffened panels considering structure performance), we have confirmed the applicability of the proposed method for multi-objective side constraint optimization problems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.3
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• pp.434-441
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• 1994

In this paper, performance of MAP management system traffic is analyzed, to realize the network management function in automated manufacturing network mini-MAP. The network management system, which controls and supervises the network resources in the communication network, is the function that is necessarily required in this network. Since the real time response must be required in the Mini-MAP network, the delay performance of the network needs to be analyzed. By means of both analytical method and simulation for cyclic queueing model, the delay time distributions due to the increasement of transmission data are obtained in the implemented management network where SLAM II package is used for simulation. In addition, the parameters of the management function affecting the transmission delay are considered so that these parameters can be used to implement network management system.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.71
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• pp.325-350
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• 2016

As the new competitive environment become more global, technologically oriented and customer driven, as customers continually demand higher quality, faster response, and greater reliability of products and services, the new global market demands a more customer responsive behaviour by companies and firms have responded with innovative products and improved manufacturing processes to manufacture products. Further, the shift from traditional manufacturing and purchasing to JIT manufacturing and purchasing requires customers and suppliers to shift from adversarial relationships to strategic partnerships, and information sharing, so as to attain flexibility, reliability, and speed. SCM practices such as supplier collaboration and information sharing is considered as a key to attaining supplier network responsiveness and enhancing the product innovation and the market access time. The current research investigates the effect of SCM practices on supplier network responsiveness, the product innovation and the market access time of export companies. Thus by providing empirical evidence of the said relationships, this study offers useful guidelines for measuring and improving the supplier network responsiveness of a firm, facilitating further research in the area.

• International Journal of Automotive Technology
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• v.6 no.1
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• pp.71-77
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• 2005

This paper presents a systematic approach which determines the optimal period to minimize performance measure subject to the schedulability constraints of a real-time control system by formulating the scheduling problem as an optimal problem. The performance measure is derived from the summation of end-to-end response times of processed I/Os scheduled by the static cyclic method. The schedulability constraint is specified in terms of allowable resource utilization. At first, a uniprocessor case is considered and then it is extended to a distributed system connected through a communication link, local-inter network, UN. This approach is applied to the design of an automotive body control system in order to validate the feasibility through a real example. By using the approach, a set of optimal periods can easily be obtained without complex and advanced methods such as branch and bound (B&B) or simulated annealing.

• Computers and Concrete
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• v.27 no.3
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• pp.269-282
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• 2021

A dynamic analytical solution for a simply supported, rectangular functionally graded plate with a porous middle layer under time-dependent load based on a refined third-order shear deformation theory with a cubic variation of in-plane displacements according to the thickness and linear/quadratic transverse displacement is presented. The solution achieved in the trigonometric series form and rests on the Green's function method. Two porosity types and their influence on material properties, and mechanical behavior are considered. The network of pores is assumed to be empty or filled with low-pressure air, and the material properties are calculated using the power-law distribution idealization. Numerical calculations have been carried out to demonstrate the accuracy of the kinematic model for the dynamic problem, the effect of porosity, thickness of porous layers, power-law index, and type of loading on the dynamic response of an imperfect functionally graded material plate.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.121-124
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• 2001

In industrial actual control system, PID controller has been used with its high delicate control system in position control system. PID controller has simple structure and superior ability in several characteristics. When the response of system is changed by delay time, variable load , disturbances and external environment, control gain of PID controller must be readjusted on the system dynamic characteristics. Therefore, a control ability of PID controller is degraded when th control gain is inappropriately determined. When the response characteristic of system is changed under a condition, control gain of PID controller must be changed adaptively to be a waited response of system. In this paper an adaptive-tuning type PID controller is constructed by self-recurrent Neural Network(SRNN). applying back-propagation(BP) algorithm. Form the result of computer simulation in the proposed controller, its usefulness is verified.