• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.133-134
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• 2006

In this paper the platform system for IEEE 802.15.4 Low Rate WPAN is designed and fabricated. IEEE 802.15.4 Low Rate WPAN system serves the functions and realization of home-area network. According to the IEEE 802.15.4 standard, there are two modes, One is BPSK modulation in 868/915MHz frequency band. The other is O-QPSK modulation in 2.45GHz frequency band. In this paper we implemented the platform system mounted in one PCB board in 868/915MHz frequency band of IEEE 802.15.4 Low Rate WPAN system. We measured that the platform system which consists of digital part and RF part has good performance. Also RF part is realized by design and fabrication of the RF transceiver IC. The key issue is to make the platform system which provides the function of Low Rate WPAN system to meet the requirement of IEEE 802.15.4 standards.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.157-158
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• 2008

This paper examines an adaptive coding scheme for flat fading channels to maximize the average code rate of a coded system. The proposed adaptation technique is employed by using the required free distance of a rate compatible code depending on the channel realization. First, the system will calculate the required free distance based on the instantaneous channel gain. Based on this channel gain we will select a set of convolution code to optimize the code rate with a certain performance requirement. Simulation results show that our proposal can achieve a higher code rate.

• MALSORI
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• no.47
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• pp.1-13
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• 2003

The purpose of this paper is to research the correlation between frequency and the deletion of /w, (equation omitted)/ in Korean. For this purpose, I select 11 words from the frequency data, then, analyze the speech of 20 speakers of standard Korean. As a result, I can find that there is correlation between the frequency and the deletion rate of segment. The rate of deletion is higher in high frequency words, while the rate of realization is higher in low frequency words. Although there is correlation between the frequency and the deletion rate of segment, the feature of segment, prosodic environments are more important in segment deletion.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.568-570
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• 2004

The error-backpropagation (EBP) algerithm for training multilayer perceptrons (MLPs) is known to have good features of robustness and economical efficiency. However, the algorithm has difficulty in selecting an optimal constant learning rate and thus results in non-optimal learning speed and inflexible operation for working data. This paper Introduces an elastic learning rate that guarantees convergence of learning and its local realization by online upoate of MLP parameters Into the original EBP algorithm in order to complement the non-optimality. The results of experiments on a speaker verification system with Korean speech database are presented and discussed to demonstrate the performance improvement of the proposed method in terms of learning speed and flexibility fer working data of the original EBP algorithm.

• Journal of Korean society of Dental Hygiene
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• v.9 no.2
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• pp.89-98
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• 2009

This study did question, and got following conclusion to ready necessary basic data to develop school oral health educational programs because grasp 388 man high school students in Jeolla-bukdo Namwon per June, 2008 realization about oral health and oral health education actual conditions. 1. Students of 56.7% recognized own oral health as is not healthy in realization about subjective oral health, and students of 72.2% were interested in oral health, and was recognizing oral fitness by important health problems. 2. Oral health realization by class was significant difference in toothbrushing reason, cause of dental caries, cause of periodontal disease. Students who respond that know adjusted water fluoridation did only for 10.3%, and it was 43.0% of students who responded that students of 57.0% do toothbrushing because of draft cleanliness, and responds that cause of dental caries is food dregs. 3. Responded that 87.1% is right toothbrushing by oral disease preservative, and next time was on-time oral medical examination 79.4%, smoking resection 58.5%, sugar intake limitation 55.4% round. 4. Students, who oral health education by interest degree of oral health is interested in oral health, is oral health educational experience and the need rate, participation intention was high when educate.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.395-400
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• 1991

In spinning satellite, a gyrotorquer generates a control torquer along two orthogonal axes normal to the spin axis of the vehicle. Matrix Fraction Description(MFD) are used to obtain minimal realization of the transfer matrix relating the attitude angles and the rate of rotation of the gimbals of gyrotorquer. In this paper, the Linear Quadratic Gaussian with Loop Transfer Recovery and H.meihodologies are used to design controller for spinning satellite.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.340-343
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• 2005

A realization for digital multimedia receiving system using Conditional Access System is presented in this paper. The key word for descrambling is make from smart card and Conditional Access System, a Stabilization is grow up in the method. It is possible to decoding that of average 15 fame/second of H.264 video format and that 24Khz${\sim}$48Khz audio sample rate using dual processor that of high performance DSP and RISC. This system is evaluated correct descrambling procedure in test stream added that signed user data.

• Journal of Biosystems Engineering
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• v.37 no.3
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• pp.192-200
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• 2012

Purpose: Aerial application of chemicals with an agricultural helicopter allows for precise and timely spraying and reduces working labor and pollution. An attitude controller for an agricultural helicopter would be helpful to aerial application operator. The objectives of this paper are to determine the transfer function models and to estimate the handling qualities of a bare-airframe model helicopter. Methods: Transfer functions of a model unmanned helicopter were estimated by using NAVFIT and DERIVID modules of the $CIFER^{(R)}$ program to the time history data of frequency sweep flight tests. Control inputs of the transfer functions were elevator, aileron, rudder and collective pitch stick positions and the outputs were resulting on-axis movements of the fuselage. Results: Minimum realization of the transfer functions for pitch rate output to elevator control input and roll rate output to aileron control input produced second order transfer functions with undamped natural frequencies around 3.0 Hz and damping ratios of 0.139 and 0.530, respectively. The equivalent time delays of the transfer functions ranged from 0.16 to 0.44 second. Sensitivity analysis of the proposed parameters allowed derivation of minimal realization of the transfer functions. Conclusions: Handling quality of the model helicopter was addressed based on the eigenvalues of the transfer functions, corresponding undamped natural frequencies with damping ratios. The equivalent time delays of the lateral-directional motion ranged from 0.16 to 0.44 second, longer than the 0.1 to 0.15 second requirement for well-controlled typical manned aerial vehicles.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.991-998
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• 2010

In realization of wireless home network system using speech recognition in indoor voice recognition environment, background noise and reverberation are two main causes of digression in voice recognition system. In this study, the home network system resistant to reverberation and background noise using voice section detection method based on spectral entropy in indoor recognition environment is to be realized. Spectral subtraction can reduce the effect of reverberation and remove noise independent from voice signal by eliminating signal distorted by reverberation in spectrum. For effective spectral subtraction, the correct separation of voice section and silent section should be accompanied and for this, improvement of performance needs to be done, applying to voice section detection method based on entropy. In this study, experimental and indoor environment testing is carried out to figure out command recognition rate in indoor recognition environment. The test result shows that command recognition rate improved in static environment and reverberant room condition, using voice section detection method based on spectral entropy.

• Phonetics and Speech Sciences
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• v.12 no.1
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• pp.19-31
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• 2020

The purpose of this study is to observe the realization of pause and breath groups from adult speakers and to examine how gender, generation, and tasks can affect this realization. For this purpose, we analyzed forty-eight male or female speakers. Their generation was divided into two groups: young, old. Task and gender affected both the realization of pause and breath groups. The length of the pause groups was longer in the read speech than in the spontaneous speech and female speech. On the other hand, the length of the breath group was longer in the spontaneous speech and the male speech. In the spontaneous speech, which requires planning, the speaker produced shorter length of pause group. The short sentence length of the reading material influenced the reason for which the length of the breath group was shorter in the reading speech. Gender difference resulted from difference in pause patterns between genders. In the case of the breath groups, the male speaker produced longer duration of pause than the female speaker did, which may be due to difference in lung capacity between genders. On the other hand, generation did not affect either the pause groups or the breath groups. The generation factor only influenced the number of syllables and the eojeols, which can be interpreted as the result of the difference in speech rate between generations.