• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1162-1167
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• 2004

This paper presents the design methodology of digital fuzzy controller(DFC) for the systems with time-delay. We propose the fuzzy feedback controller whose output is delayed with unit sampling period and predicted. The analysis and the design problem considering time-delay become easy because the proposed controller is syncronized with the sampling time. The stabilization problem of the digital fuzzy system with time-delay is solved by linear matrix inequality(LMI) theory. Convex optimization techniques are utilized to solve the stable feedback gains and a common Lyapunov function for designed fuzzy control system. To show the effectiveness the proposed control scheme, the network control example is presented.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.9
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• pp.459-466
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• 2000

The performance of a commercialized power system stabilizer (PWX-600) for a single hydro-turbine generator and infinite bus system has been investigated using Real Time Digital Simulator (RTDS) in this paper. The test system was composed of RTDS, three phase voltage/current amplifier and the PSS. The test scheme provided a very efficient way to verify the design and control performance of a PSS to be applied to real power system. The scheme can also be applied to verify in real time the performance of hardware and software of power system controllers for FACTS and protective relays effectively.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.220-222
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• 2006

This paper presents intelligent digital redesign method of global approach for hybrid state space fuzzy-model-based controllers. For effectiveness and stabilization of continuous-time uncertain nonlinear systems under discrete-time controller, Takagi-Sugeno(TS) fuzzy model is used to represent the complex system. And global approach design problems viewed as a convex optimization problem that we minimize the error of the norm bounds between nonlinearly interpolated lineal operators to be matched. Also, by using the bilinear and inverse bilinear approximation method, we analyzed nonlinear system's uncertain parts more precisely. When a sampling period is sufficiently small, the conversion of a continuous-time structured uncertain nonlinear system to an equivalent discrete-time system have proper reason. Sufficiently conditions for the global state-matching of the digitally controlled system are formulated in terms of linear matrix inequalities (LMIs). Finally, a T-S fuzzy model for the chaotic Lorentz system is used as an example to guarantee the stability and effectiveness of the proposed method.

• International Journal of Advanced Culture Technology
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• v.5 no.1
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• pp.51-57
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• 2017

Digital signage is becoming part of daily life across a wide range of visual advertisements segments market used in stations, hotels, retail stores, hotels, etc. The current digital signage system used in market is generally works on limited user interactivity with static contents. In this paper, a new approach is proposed using computer vision based dynamic audience adaptive cost-effective digital signage system. The proposed design uses the Camera attached Raspberry Pi Open source platform to employ the real-time audience interaction using computer vision algorithms to extract facial features of the audience. The real-time facial features are extracted using Haar Cascade algorithm which are used for audience gender specific rendering of dynamic digital signage content. The audience facial characterization using Haar Cascade is evaluated on the FERET database with 95% accuracy for gender classification. The proposed system, developed and evaluated with male and female audiences in real-life environments camera embedded raspberry pi with good level of accuracy.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.314-320
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• 2005

In this paper, a methodology for estimating the parameters of a discrete-time system and designing a digital PID controller based on the estimated model and a genetic algorithm is presented. To deal with optimization problems occurring regarding parameter estimation and controller design, a pseudo parallel genetic algorithm (PPGA) is used. The parameters of a discrete-time system are estimated using both the model technique and a PPGA. The digital PID controller is described by the pulse transfer function and its parameters are tuned based on both the model reference technique and another PPGA. A set of experimental works on two processes are carried out to illustrate the performance of the proposed method.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.724-727
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• 1993

This paper is presented real-time digital control techniques of the PWM inverter for UPS. This proposed system is based on instantaneous digital control scheme which is empolyed double dead beat control and prediction method. Especially, to supply the load current from the inverter without the computation delay, the predictive methods are used to generate the load current signal. From the simulation and experimental results, it is shown that presented scheme has good performance such as very low THD of the output voltage, and good dynamic response under the nonlinear load. The experimental implementation of the system is estabilished by using the TMS320C25 DSP.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1671-1676
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• 1991

Direct digital design of computed torque controllers for a robot manipulator is discussed in this paper. A simple discrete-time model of the robot manipulator obtained by Euler's method is used for the design. Taking account of computation delay in the digital processor, we propose predictor-based designs of the PD and PID type controllers. The PID type controller is designed based on a modified version of the discrete-time integral controller proposed by Mita. For both controllers, the same formulas can be used to determine the feedback gains. A simulation example is presented to compare the robustness of the proposed controllers against physical parameter variations.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.155-157
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• 2005

Digital relays have numerous advantages over traditional analog relays, such as the ability to accomplish what is difficult or impossible using analog relays. This paper presents the protective relay modeling of generator using Real Time Digital Simulator(RTDS). The developed model is applied to the test system and the simulation results are evident that they performs satisfactory.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.4
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• pp.652-657
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• 1987

This paper describes an application of CMOS Gate Array Integrated Cricuits to the implementation of three functional units: A Multiplexer, Time Switch, and Demultiplexer in the Switching Network and Digital Line Concentrator of TDX-1 system, which is a fully digital time division electronic switching system in Korea. The application of CMOS Gate Array Integrated Circuits significantly improves the overall system performance in terms of power consumption, cost, size, reliability, and timing margin, etc.

• Korean Journal of Computational Design and Engineering
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• v.10 no.3
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• pp.210-216
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• 2005

Digital manufacturing could be very effective in shipbuilding in order to estimate the process time, to improve the operation efficiency, and to prevent bottleneck processes in advance. The subassembly process having done research consists of piece arrangement, tack welding, robot welding, manual welding and so on. The robot welding of them was the focus of the simulation. The analysis and modeling were carried out by using UML (Unified Modeling Language) as well as $IDEF\phi$ (Integration DEFinition). The characteristics of the process resources were analyzed using the shipyard data, and the layout of the subassembly line was designed with the resources. Using the constructed resource and process model, the productivity and efficiency of changed robot welding stage were investigated. It was simulated how much the variations in the resource performance have influence on improvement of productivity. One of the important outputs in this simulation was the cycle time during a certain period's work. The cycle time prediction was also undertaken for the different torch and the different piece arrangement. The proposed model was established three-dimensionally in a digital environment so that interferences among objects and space allocations for the resources could be easily investigated.