• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.1
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• pp.28-35
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• 2012

This paper presents the method for $H_{\infty}$ fuzzy controller design of discrete-time fuzzy Markovian jump systems with state and input time delays. The Takagi and Sugeno fuzzy model is employed to represent a delayed nonlinear system that possesses Markovian jump parameters. A stochastic mode dependent Lyapunov function is employed to analyze the stability and $H_{\infty}$ disturbance attenuation performance of the fuzzy Markovian jump systems with state and input time delays. A sufficient condition for the existence of fuzzy $H_{\infty}$ controller is given in terms of matrix inequalities. Also numerical example is presented to illustrate the efficiency of the proposed design method.

• Journal of Korean Society of Transportation
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• v.20 no.4
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• pp.73-82
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• 2002

The influence of bus stops near signalized intersections is one of the important factors which cannot be negligible in the analysis of the capacity of signalized intersections. Absence of consideration of bus bay can reduce capacity and increase the time that the stop of buses block other traveling vehicles. This influence is reflected by the bus blockage adjustment factor in KHCM, but the factor does not consider the course of each bus passing the intersection. Particularly, left turn buses have more influence on the capacity than the other buses and require the minimum length of the road for lane changes. All the existing criteria can apply only to arterial roads on which mostly traffic flows are continuous. And the criteria. which can determine the optimum location and the minimum distance between a signalized intersection and a bus bay, is not prepared and the related study is insufficient. Therefore, a theoretical formula is derived in this study being based on the theories which are avaliable to apply to the situation of signalized intersections.

• Journal of Korean Society of Transportation
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• v.28 no.1
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• pp.143-156
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• 2010

The walking is very important because of its environment friendly and low accident rate, and transferring is also important as increasing public transportation uses. Facilities for transferring such as transfer path in Sadang station and internal stairways in Sindorim station are the object of this paper. Using preexistence methodology for Level of Service is not appropriate to transferring facilities because they are occurred only when the train arrive that station. To solve this problem, this paper uses queuing theory and utilization factor. In result, we can get Level of Service which can simulate real situation of the facilities by using new methodology which introduce by this paper. Also it reveals that preexistence methodology cannot simulate real phenomenon in transferring center.

• Journal of the Korean GEO-environmental Society
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• v.15 no.3
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• pp.41-48
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• 2014

Experimental study of sedimentation and self-weight consolidation has been primary research area in dredged soil. However, good quality of the dredged soil and minimum water pollution caused by the pumping of reclaimed soil require intensive study of the flow characteristics of dredged material due to dumping. In this study, continuity and the equilibrium equations for mass flow assuming single phase was derived to simulate mass flow in dredged containment area. To optimize computation and modeling time for three dimensional geometry and boundary conditions, depth integration is applied to governing equations to consider three dimensional topography of the site. Petrov-Galerkin formulation is applied in spatial discretization of governing equations. Generalized trapezoidal rule is used for time integration, and Newton iteration process approximated the solution. DG and CDG technique were used for weighting matrix in discontinuous test function in dredged flow analysis, and numerical stability was evaluated by performed a square slump simulation. A comparative analysis for numerical methods showed that DG method applied to SU / PG formulation gives minimal pseudo oscillation and reliable numerical results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9A
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• pp.784-789
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• 2011

In this paper, a precoder based on limited phase feedback is proposed to maximize user's receive signal-to-interference-plus-noise ratio (SINR) in coordinated multi-point (CoMP) coordinated scheduling / coordinated beamforming (CS/CB) precoding matrix indicator (PMI) scenario. Most conventional precoding techniques based on limited phase feedback have been considered in a single-cell environment. However, considering neighboring cells in a multi-cell environment, we enhance the conventional preocoding. method. First, to maximize receive SINR, precoding matrices are designed to maximize the serving cell's signal and to minimize the coordinated cells' signal. Also, a precoder which can be used in a limited bit feedback condition is suggested. Finally, the proposed precoder's performance is evaluated and compared with some other precoding techniques by using simulation under the CoMP CS/CB PMI scenario.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.6
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• pp.779-786
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• 2009

This paper deals with $H_{\infty}$ fuzzy control problem of discrete-time nonlinear Markovian jump systems with time delay. The Takgi and Sugeno fuzzy model is employed to represent a delayed nonlinear system that possesses Markovian jump parameters. A stochastic mode dependent Lyapunov function is employed to analyze the stability and $H_{\infty}$ disturbance attenuation performance of the Markovian jump fuzzy system with time delay. Stochastic Lyapunov function is dependent on the operation modes of the system. A sufficient condition for the existence of fuzzy $H_{\infty}$ controller are given in terms of matrix inequalities. Also numerical example is presented to illustrate the efficient of the proposed design methods.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.3
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• pp.449-457
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• 2017

In this paper, we analyze the security and performance of the Quantis Quantum random number generator in terms of cryptography through experiments. The Quantis' post-processing is designed to output full-entropy via bit-matrix-vector multiplication based on mathematical background, and we used the min-entropy estimating test of NIST SP 800-90B so as to verify whether the output is full-entropy. Quantis minimizes the effect on the random bit rate by using an optimization technique for bit-matrix-vector multiplication, and compared the performance to conditioning functions of NIST SP 800-90B by measuring the random bit rate. Also, we have distinguished what is in Quantis' post-processing to the standard model of NIST in USA and BSI in Germany, and in case of applying Quantis to cryptographic systems in accordance with the CMVP standard, it is recommended to use the output of Quantis as the seed of the approved DRBG.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.25 no.1
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• pp.18-23
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• 1989

An approach for robustness recovery of the observer-based control system is presented. The approach is developed by adding a loop with appropriate constant matrix to the observer-based closed-loop system. It will be shown that if there exists an added-loop matrix M satisfying F=MC for a feedback gain F and output matrix C, then the observer-based control systems have the same loop transfer functions as full-state feedback implementations, in other words, the former has the same relative stability and robustness as the latter.

• Korean Journal of Optics and Photonics
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• v.33 no.3
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• pp.106-112
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• 2022

A two-dimensional optical code division multiple access (OCDMA) encoder/decoder, which is composed of add/drop filters and all-pass filters for delay operation, is proposed. An example design is presented, and its feasibility is illustrated through numerical simulations. The chip area of the proposed OCDMA encoder/decoder could be about one-third that of a previous OCDMA device employing delay waveguides. Its performance is numerically investigated using the transfer-matrix method combined with the fast Fourier transform. The autocorrelation peak level over the maximum cross-correlation level for incorrect wavelength hopping and spectral phase code combinations is greater than 3 at the center of the correctly decoded pulse, which assures a bit error rate lower than 10^-3, corresponding to the forward error-correction limit.

• Journal of the Korean Institute of Telematics and Electronics
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• v.18 no.4
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• pp.34-42
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• 1981

A 512-bit Task Programmable ROM has been designed and fabricated using PMOS technology. The content of the memory was written through the gate pattern during the fabrication process, and was checked by displaying the output of the chip on an oscilloscope with 512(32$\times$16) matrix points. The operation of the chip was surcessful with operating voltage from -6V to -l2V, The power consumption and propagation delay time have been measured to be 3mW and 13 $\mu$sec, respectively at -6 Volt. The power consunption increased to 27mW and propagation delay time decreased to 3$\mu$sec at -12V. The output of the chip was capable of driving the input of a TTL gate directly and retained a high impedence state when the chip solect function disabled the output.