• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.125-132
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• 2011

Drought is a major limiting factor in turfgrass management. Turfgrass responses to water deficit depend on the amount and the rate of water loss as well as the duration of the stress condition. This review paper was designed to understand responses such as photosynthesis, canopy spectral reflectance, plant cell, root, hormone and protein alteration when turfgrass got drought stress. Furthermore, mechanisms to recover from drought conditions were reviewed in detail. However, there are still many questions regarding plant adaptation to water deficit. It is not clear that the mechanism by which plants detect water deficit and transfer that signal into adaptive responses. Turfgrass research should focus on the best management practices such as how to enhance the ability of self-defense mechanism through understanding plant responses by environmental stress.

• The Journal of the Acoustical Society of Korea
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• v.14 no.5
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• pp.51-57
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• 1995

In this paper, we study a noise-robust feature extraction method of speech signal based on auditory modeling. The auditory model consists of a basilar membrane, a hair cell model and spectrum output stage. Basilar membrane model describes a response characteristic of membrane according to vibration in speech wave, and is represented as a band-pass filter bank. Hair cell model describes a neural transduction according to displacements of the basilar membrane. It responds adaptively to relative values of input and plays an important role for noise-robustness. Spectrum output stage constructs a mean rate spectrum using the average firing rate of each channel. And we extract feature vectors using a mean rate spectrum. Simulation results show that when auditory-based feature extraction is used, the speech recognition performance in noisy environments is improved compared to other feature extraction methods.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.3
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• pp.139-149
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• 2015

In this paper, we describe a new approach to perform real-time implementation of an robust controller for robotic manipulator based on digital signal processors in this paper. The Texas Instruments DSPs chips are used in implementing real-time adaptive control algorithms to provide enhanced motion control performance for dual-arm robotic manipulators. In the proposed scheme, adaptation laws are derived from model reference adaptive control principle based on the improved direct Lyapunov method. The proposed adaptive controller consists of an adaptive feed-forward and feedback controller and time-varying auxiliary controller elements. The proposed control scheme is simple in structure, fast in computation, and suitable for real-time control. Moreover, this scheme does not require any accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the proposed adaptive controller is illustrated by simulation and experimental results for robot manipulator consisting of dual arm with eight degrees of freedom at the joint space and cartesian space.

• 전자공학회논문지 IE
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• v.43 no.3
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• pp.34-40
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• 2006

Usually, fluid or fuel supply device need space to need special sensor to control motor, attaches with ancillary equipment to attach sensor. Also, difficult point follows need signal line and other circuit etc. In this paper, used that proposed control system that use hall sensor to solve discomfort and problem and difference control principle of system happens in current flow according to motor action step. Also, could reduce breakdown by sensor establishment, reduce material costs and personnel expenses as well as control system superior. Auto-pumping system sees that will can apply, develop several kind of device that use system hereafter to all fluid supply systems through soft-ware adaptation.

• Journal of Communications and Networks
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• v.10 no.1
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• pp.71-78
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• 2008

We propose a sub-band spreading technique for adaptive modulation (AM) in orthogonal frequency division multiplexing (OFDM) systems in order to reduce signaling overheads and to average frequency selective fading channels causing different signal-to-noise ratio (SNR) values for subcarriers in each subband. The conventional sub-band based AM schemes can also reduce signaling overheads and complexity for allocating a resource per sub-band at a time. However, they may suffer from the channel variation in a sub-band when the sub-band size is larger than the channel coherence bandwidth (BW). The sub-band spreading at the transmitter enables the received symbols in each sub-band to have an identical reliability even in a frequency selective fading channel. We rigorously analyze the averaged SNR value at the receiver of the sub-band spreading system and the analyzed average SNR in a sub-band is used for an adaptation criterion. The proposed AM scheme outperforms the conventional sub-band based OFDM scheme without spreading, and it can yield better throughput performance than the conventional subcarrier based AM schemes when we consider the signaling overheads.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1999.03a
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• pp.221-230
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• 1999

Automobile horn's psychoacoustic characteristic and significance as a anturalistic signal of danger makes it a valuable auditory stimulus to study such psychophysiological responses as startle, orienting and defense reactions. However, comparison and differentiation of physiological responses to commercially available horns is a complicated task due to small contrast of technical features of horns and influence of such processes as habituation on physiological outcome with increased number of auditory stimulation trials. In the study on 10 college students we performed comparative analysis of tonic and phasic reactivity of physiological responses mediated by autonomic nervous system in order to identify role of habituation and decrement of autonomic responsivity, as well as possibility o differentiate subjectively most and least preferred and subjectively more appropriate horns according to physiological manifestations. It was showed that electrodermal and cardiovascular reactivity have concurrent patterns of adaptation to repeated stimulation, namely skin conductance variables habituated, cardiac reactivity failed to show signs of habituation, while vascular component of response were facilitated demonstrating marked sensitization. Differentiation of Physiological responses to horns with respect to their subjective rating scores was possible, however electrodermal reactivity was effective only at the first block of trials, while phasic and tonic cardiovascular reactivity differentiate responses during whole course of experiment. There are discussed possible autonomic mechanisms involved in mediation of observed results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.6B
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• pp.559-568
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• 2002

In this paper, we studied on combining the control of transmission fates and power for the real system where a finite set of transmission rates are used. In [1], the combined control of transmission rates and power was first researched, and suggested the Selective Power Control (SPC) algorithm. However, it can't guarantee the minimum rate to each user and results in frequent changes of rate due to oscillation of the SIR (Signal to Interference Ratio) values. As a main purpose of this paper, we derive a formulation model and propose a distributed iteration algorithm to solve these problems. To evaluate the performance of the proposed algorithm, we carried out numerical analysis and computational experiments. The results indicate that the proposed algorithm achieves better throughput than conventional one by keeping the low average transmission power.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2A
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• pp.91-99
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• 2011

Several repeater systems are used to enhance the cell coverage to location such as shadow and rural areas in mobile systems. But the general RF repeater solutions are not suitable for high power outdoor environment because it has the weakness such as self oscillation problem With adoption of a adaptive digital filter technology, feedback interference cancellation repeater prevents oscillation by detecting and canceling the unwanted feedback signal between transmission and receiver antenna. In this paper, dual NLMS based interference cancellation method is proposed and the step size adaptation can be implemented by the estimation of the feedback channel Doppler frequency characteristics. The performance of the proposed algorithm is quantified via analysis and simulation for the static and multipath fading feedback channels.

• ETRI Journal
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• v.38 no.6
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• pp.1052-1063
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• 2016

We propose a millimeter wave (MMW)-based mobile hotspot network (MHN) system for application in high-speed railways that is capable of supporting a peak backhaul link throughput of 1 Gbps per train at 400 km/h. The MHN system can be implemented in subways and high-speed trains to support passengers with smart devices and provide access to the Internet. The proposed system can overcome the inherent high path loss in MMW through system designs and high antenna gains. We present a simulation of the system performance that shows that a fixed beamforming strategy can provide high signal-to-interference-plus-noise-ratio similar to those of an adaptive beamforming strategy, with the exception of 15% of the train path in which the network can use link adaptation with low-order modulation formats or trigger a handover to maintain the connection. We also demonstrate the feasibility of the MHN system using a test bed deployed in Seoul subway line 8. The backhaul link throughput varies instantaneously between 200 Mbps and 500 Mbps depending on the SNR variations while the train is running. During the field trial, the smartphones used could make connections through offloading.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.6
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• pp.1135-1141
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• 2004

In this study, this system makes use of the analog infrared rays sensor and converts the feature of fish outline when sensor is operating with CPU(80C196KC). Then, after signal processing, this feature is classified a special feature and a outline of fish by using the neural network, one of the artificial intelligence scheme. This neural network classifies fish pattern of very simple and short calculation. This has linear activation function and the error back propagation is used as a teaming algorithm. And the neural network is learned in off-line process. Because an adaptation period of neural network is too long when random initial weights are used, off-line teaming is induced to decrease the progress time.