• Science of Emotion and Sensibility
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• v.11 no.2
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• pp.227-234
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• 2008

Graphic and sounds are mainly used for presenting digital content as general. It has been reported that the reality of digital contents was improved by adding haptic factor to the contents of graphic and sounds. Therefore, various haptic system have recently been developed for implementing haptic sensation into digital contents. However, the delay of haptic display sometimes happens due to low hardware performance and causes to deteriorate reality of digital contents. The delay effect on reality has been important to be determined for presenting digital contents with haptic system. Therefore, this study is to find the effect on user's cognition of digital contents evoking both visual and haptic sensation. Eight university students performed 4 repetitive tasks of pushing cube under the two conditions of visual and haptic delay. The delay time of each condition were set 0.5, 1.0, 2.0 and 4.0 second. As the result, both haptic and visual delay were negatively influenced user's recognition while visual delay showed more dominant effect on user's recognition than haptic delay.

• Korean journal of communication and information
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• v.19
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• pp.185-211
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• 2002

Media convergence is prevalent all over the world, and is expected to change our lives dramatically in near future. Chaos theory is a new emerging theoretical approach to various social phenomena including organization management, economic system, stock market fluctuation, and so on. This thesis is intended to explain media convergence phenomena centered on internet media using basic concepts of chaos theory such as self-organization, co-evolution, and feedback loop. The implications of this tentative study are that we can apply chaos theory to media convergence as other social or natural phenomena, and that maintaining chaos state of media system is useful for accelerating creativities, and that developing media system as an organic system to cooperate with other relevant systems is helpful for promoting life qualities, and that establishing moral order or root value is desirable for implementing communicatopia.

• Journal of Korea Multimedia Society
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• v.10 no.1
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• pp.49-57
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• 2007

Recently, CMOS RF integration has been widely explored in the wireless communication area to save cost, power, and chip area. The direct conversion architecture, rather than a more conventional super-het-erodyne, has been an attractive choice for single-chip integration because of its many advantages. However, the direct conversion architecture has several fundamental problems to solve in achieving performance comparable to a super-heterodyne counterpart. In this paper, we describe a programmable filter for mobile communication terminals using a direct conversion architecture. The proposed filter can be implemented with the active-RC filter and programmed to meet the requirements of different communication standards, including GSM, DECT and WCDMA. The filter can be tuned to select a detail frequency by changing the gate voltage of the MOS resistors. The gain of the proposed architecture can be programmed from 27dB to 72dB using the filter gain and VGA in 3dB steps.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.6
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• pp.509-516
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• 2002

This paper presents a simple torque estimation method and switching angle control of Switched Reluctance Motor(SRM) using Neural Network(NN). SRM has gaining much interest as industrial applications due to the simple structure and high efficiency. Adaptive switching angle control is essential for the optimal driving of SRM because of the driving characteristic varies with the load and speed. The proper switching angle which can increase the efficiency was investigated in this paper. NN was adapted to regulate the switching angle and nonlinear inductance modelling. Experimental result shows the validity of the switching angle controller.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.1
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• pp.50-56
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• 1999

This paper presents consideration on validity of instantaneous correlation power theory. The proposed power theory is defined and analyzed by time domain approach, thus it is easy to understand and instrument. The power is decomposed into active, fundamental reactive and harmonics components based on the autocorrelation and crosscorrelation signal techniques between voltage and current waveforms. On the compensation property, active power filter deal with three components only. Also, for real time control of active power filter, the power models with difficult concept are not cost effective. To verify the validity of the instantaneous correlation power theory, experimental work for voltage type DSP based active power filter is achieved. The power of thyristor controlled motor drives is decomposed into three orthogonal components by proposed power theory. From compensation results, validity of proposed theory is confirmed. feedback controller needs the information on some motor parameters. New recursive adaptation algorithms for rotor resistance and mutual inductance which can be applied to our nonlinear feedback controller are also presented in this paper. The recursive adaptation algorithms make the estimated values of rotor resistance and mutual inductance track their real values. Some simulation and experimental results show that the adaptation algorithms are robust against the variation of stator resistance and stator inductance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2951-2957
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• 2010

In solar industry the development of tracking PV power generation devices progresses favorably because of its efficiency, comparing with fixed PV power generation devices. Tracking PV power generation device are not only preserving the amount of solar radiation per unit area but also maximizing the efficiency of solar battery. Therefore accurate and low-priced solar position tracking devices are very important to improve the economical efficiency and lower invest price. This research is concerned with solar position algorithm with uncertainties equal to 1 minute($0.016^{\circ}$) using the mathmatics and astronomg. Proposed algorithm in this paper, lowers the implementation price and improves power generation efficiency. In view of the result so far achieved, maximum error has 30 secend($0.008^{\circ}$). And the solar cell generating system applied by this algorithm showed the gain of the fixed type contrast average 23W(about 18%).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.134-140
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• 2003

In this paper, a hardware implementation of gas flow meter for accuracy improvement and saving repair costs at a field is investigated. An adaptive filter using LMS algorithms for estimating cavity vibration frequencies in noisy environments is also studied. The proposed cavity gas flow meter measures cavity sound signals in gas flow tube using microphone and signal processing systems estimate the cavity vibration frequency from the measured signal. The flow velocity and flow quantity can be calculated using the estimated cavity vibration frequency. Since cavity vibration frequency is corrupted by the environmental noise, an adaptive filter using NLMS algorithms is used for cancelling the environmental noise. Experiments using 1MS32OC32 digital signal processor are performed to show the effectiveness of the proposed system.

• Journal of the Korea Concrete Institute
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• v.21 no.5
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• pp.549-556
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• 2009

This research analyzed the structural efficiency and application by improving the 100 mm width vertical joint to 150 mm and developing three connection methods to reduce the difficulty in assembling and handling PC walls. Moreover, nonlinear finite analysis was used for analyzing. From the analysis results, when double width connection was applied, the PC wall showed larger load capacity and ductility due to the steel bar sharing loads efficiently. Moreover, as the dimension of loops and the number of bars increased, the maximum load capacity increased as well. Also, among the double width connections, the largest capacity showed in the order of welding, ring and C type loop. However, in case of welding type loop connection, the ring type loop is more stable due to changes in different site conditions. Therefore, thorough quality control of welding is necessary.

• The Journal of the Acoustical Society of Korea
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• v.15 no.1
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• pp.23-33
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• 1996

In this paper we point out that if the classical principal domain for bispectra is utilized to determine a second-order Volterra model's output, such and output will be incomplete. This deficiency is associated with the periodic nature of the DFT. For this reason, the objective of this paper is to present an "extended" principal domain for Volterra kernels which leads to an improved estimate of the nonlinear system's response. In order to define the extended principal domain, we derive a new discrete frequency-domain Volterra model from a discrete time-domain Volterra model utilizing 2-dimensional DFT and the relationship between the quadratic component of the Volterra model and a square filter. The effect of the extended domain on the model output is interpreted in terms of the periodicity of DFT. Through computer simulations, we demonstrate the effects of the extended principal domain on the Volterra modeling. The simulation results indicate that the extended principal domain plays and important role in computing Volterra model outputs and estimating Volterra model coefficients.

• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.467-476
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• 1997

This paper presents a designing of a digital hearing aid processor (DHAP) chip being operated by a dedicated DSP core. The DHAP for hearing aid devices must be feasible within a size and power consumption required. Furthermore, it should be able to compensate for wide range of hearing losses and allow sufficient flexibility for the algorithm development. In this paper, a programmable 16-bit fixed-point DSP core is employed thor the designing of the DHAP. The designed DHAP performs a nonlinear loudness correction of 8 frequency bands based on audiometric measurements of impaired subjects. By employing a programmable DSP, the DHAP provides all the flexibility needed to implement audiological algorithms. In addition, the chip has low-power feature and $5, 500\times5000$$\mu$$m^2$ dimensions that fit for wearable hearing aids.