• Proceedings of the KIEE Conference
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.777-780
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• 1995

Accounting for actuator nonlinearities in control loops has often been perceived as an implementation issue and usually excluded in the design of controllers. Nonlinearities treated in this paper are saturation, and they are modelled as an inequality constraint. The CRHPC(Constrained Receding Horizon Predictive Control) with inequality constraints algorithm is used to handle actuator rate and amplitude limits simultaneously or respectively. Optimum values of future control signals are obtained by quadratic programming. Simulated examples show that predictive control law with inequality constraints offers good performance as compared with input clipping.

• The Transactions of the Korean Institute of Electrical Engineers A
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• 제48권8호
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• pp.987-995
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• 1999

A new robust controller design methodology for single-input single-output systems is proposed, where the proposed controller consists of a conventional or optimal servo controller at the outer loop as well as the robust internal-loop compensator(RIC) to eliminate the model uncertainty and external disturbance. It is shown that RIC with finite gain can make actual systems be nominal models within a prespecified error bound. And, it is also shown that RIC-based system is robustly stable regardless of input saturation. Several numerical examples are illustrated to show validities of the proposed robust controller.

• Current Optics and Photonics
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• 제7권1호
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• pp.28-32
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• 2023

Frequency characteristics of gain-saturated erbium-doped fiber amplifier (EDFA) are experimentally evaluated to mitigate the optical signal fluctuation induced by atmospheric turbulence in terrestrial freespace optical communication systems. Here, an acousto-optic modulator (AOM) is used to emulate optical signal fluctuations induced by atmospheric turbulence. The waveform which is generated in proportion to the refractive-index structural parameters is used to drive the AOM at various periodic frequencies. Thus, the dependence of the signal fluctuation suppression on the frequency is evaluated. The experiment is conducted using a periodic frequency sweep of the AOM driving voltage waveform and signal input power variation of the amplifier. It is observed that a low periodic frequency and high input signal power effectively suppress the optical signal fluctuation. This study evaluates the experimental results from the high-pass filter and gain-saturation characteristics of the EDFA.

• The Transactions of the Korea Information Processing Society
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• 제4권4호
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• pp.933-943
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• 1997

In this paper, a conernt-based image retrival system with color assigments has been stueide and implment-ed. The color of images has been extracted after changing RGB color space to HSV(hue, saturation, value)that is the most compatible color for peop]e's feeling. In the color extracting, an image is divided into 9 different areasand 3 major colors for each area are selected by using color histograms. It is possible to chose the class of umages by keywords. We are evaluate four different types of queries such as an image input, keywords with color assignments, combining an image input and keywords with color assinments, and selecting specific part of an umage. Experimental rusults show that four different query types privide precision/recall 0.55/0.37, 0.57/0.43, 0.59/0.45 and 0.63/0.61, respectively. With color assignments, the retrieval system has been able to obtain high performance and validity.

• Science of Emotion and Sensibility
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• 제15권2호
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• pp.231-238
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• 2012

This study aims for building an application system of converting sound into color image based on synesthetic perception. As the major features of input sound, both scale and octave elements extracted from F0(fundamental frequency) were converted into both hue and intensity elements of HSI color model, respectively. In this paper, we used the fixed saturation value as 0.5. On the basis of color model conversion theory, the HSI color model was then converted into the RGB model, so that a color image of the BMP format was finally created. In experiments, the basic system was implemented on both software and hardware(TMS320C6713 DSP) platforms based on the proposed sound-color image conversion method. The results revealed that diverse color images with different hues and intensities were created depending on scales and octaves extracted from the F0 of input sound signals. The outputs on the hardware platform were also identical to those on the software platform.

• Fire Science and Engineering
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• 제27권6호
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• pp.77-82
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• 2013

This research suggested smart fire recognition system which trances firing location with CCD camera with wired/wire-less TCP/IP function and Pan/Tilt function, delivers information in real time to android system installed by smart mobile communication system and controls fire and disaster remotely. To embody suggested method, firstly, algorithm which applies hue saturation intensity (HSI) Transform for input video, eliminates surrounding lightness and unnecessary videos and segmentalized only firing videos was suggested. Secondly, Pan/Tilt function traces accurate location of firing for proper control of firing. Thirdly, android communication system installed by mobile function confirms firing state and controls it. To confirm the suggested method, 10 firing videos were input and experiment was conducted. As the result, all of 10 videos segmentalized firing sector and traced all of firing locations.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제27권11C호
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• pp.1139-1151
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• 2002

In this paper, we propose the novel module-type optical space switch, employing time division multiplexing (TDM) method and multihop structure, in order to enlarge the capacity of the switching system. And we show that the proposed structure is superior over conventional ones, in terms of power loss, the number of the devices used, and signal to crosstalk (SXR). We also analyze the saturation throughput with the number of module M. As a result, the saturation throughput of the switching system with M modules is M+ 1-√(M$^2$+1), when the number of input port in a module (N) is large. Finally, we confirmed the cell loss rate (CLR) performance with the proposed switch through simulation. For example, when p=0.9, M=8 and N=32, to get the CLR that is less than or equal to 10$\^$-6/, the number of input buffers storage unit is greater than or equal to 6 and output buffers storage unit is greater than or equal to 52.

• The Journal of the Korea Contents Association
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• 제15권12호
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• pp.8-17
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• 2015

This paper presents a sound into color signal conversion using a colored-hearing synesthesia. The aim of the present paper is to implement a real-time conversion system which focuses on both hearing and sight which account for a great part of bodily senses. The proposed method of the real-time conversion of color into sound, in this paper, was simple and intuitive where scale, octave and velocity were extracted from MIDI input signals, which were converted into hue, intensity and saturation, respectively, as basic elements of HSI color model. In experiments, we implemented both the hardware system for delivering MIDI signals to PC and the VC++ based software system for monitoring both input and output signals, so we made certain that the conversion was correctly performed by the proposed method.

• Journal of the Institute of Electronics Engineers of Korea SC
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• 제38권5호
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• pp.52-58
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• 2001

In this paper, the low voltage linear tunable transconductors using the series composite transistor are presented. Due to the series composite transistor operating in the saturation region and the triode region, the proposed circuits have wide input range at low supply voltage. The designed transconductors have been simulated by HSPICE using $0.25{\mu}m$ n-welll CMOS process. Simulation results show that the cutoff frequency is 309M Hz and the THD of less than 1.1% can be obtained for the differential input signal of up to l.5VP-P with the input signal frequency of l0MHz.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.175-176
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• 2006

Electrowetting is prevailing for its various applicability on lap-on-a-chip, and MEMS devices, such as a pump, lens, micro-actuator in the micro-TAS technology. In the usual electrowetting, an AC power is preferred to DC practically. The AC electric field delays the contact angle-saturation, decreases the hysterisis, and is more stable in the view point of dielectric strength. But researches for AC electric field on electrowetting have not been reported very much yet. The different effect of AC on the electrowetting system, especially the effect of a frequency needs to be understood more concretely. In this work, the usual system for electrowetting, water droplet on the dielectric coated electrode (EWOD) is analyzed. Experimental study on the response of contact angles on input frequencies is performed. The simple circuit-model for EWOD system is considered to explain the experimental results. For more concrete understanding, the system is analyzed numerically, where simple AC-conduction model is used. Wetting tensions are analyzed under various input frequency to excavate the experimental results for the responses of the system on input frequencies.