• ETRI Journal
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• v.36 no.3
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• pp.352-360
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• 2014

This paper presents a 900 MHz zero-IF RF transceiver for IEEE 802.15.4g Smart Utility Networks OFDM systems. The proposed RF transceiver comprises an RF front end, a Tx baseband analog circuit, an Rx baseband analog circuit, and a ${\Delta}{\Sigma}$ fractional-N frequency synthesizer. In the RF front end, re-use of a matching network reduces the chip size of the RF transceiver. Since a T/Rx switch is implemented only at the input of the low noise amplifier, the driver amplifier can deliver its output power to an antenna without any signal loss; thus, leading to a low dc power consumption. The proposed current-driven passive mixer in Rx and voltage-mode passive mixer in Tx can mitigate the IQ crosstalk problem, while maintaining 50% duty-cycle in local oscillator clocks. The overall Rx-baseband circuits can provide a voltage gain of 70 dB with a 1 dB gain control step. The proposed RF transceiver is implemented in a $0.18{\mu}$ CMOS technology and consumes 37 mA in Tx mode and 38 mA in Rx mode from a 1.8 V supply voltage. The fabricated chip shows a Tx average power of -2 dBm, a sensitivity level of -103 dBm at 100 Kbps with PER < 1%, an Rx input $P_{1dB}$ of -11 dBm, and an Rx input IP3 of -2.3 dBm.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.2
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• pp.121-128
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• 2008

Accurate voice activity detection have a great impact on performance of speech applications including speech recognition, speech coding, and speech communication. In this paper, we propose methods for voice activity detection that can adapt to various car noise situations during driving. Existing voice activity detection used various method such as time energy, frequency energy, zero crossing rate, and spectral entropy that have a weak point of rapid. decline performance in noisy environments. In this paper, the approach is based on existing spectral entropy for VAD that we propose voice activity detection method using MFB(Met-frequency filter banks) spectral entropy, gradient FFT(Fast Fourier Transform) spectral entropy. and gradient MFB spectral entropy. FFT multiplied by Mel-scale is MFB and Mel-scale is non linear scale when human sound perception reflects characteristic of speech. Proposed MFB spectral entropy method clearly improve the ability to discriminate between speech and non-speech for various in noisy car environments that achieves 93.21% accuracy as a result of experiments. Compared to the spectral entropy method, the proposed voice activity detection gives an average improvement in the correct detection rate of more than 3.2%.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.1
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• pp.44-50
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• 2007

In this paper generating algorithms of the conventional chaos code sequences and a new chaos code sequence derived from the real and imaginary parts of FFT of one chaos code sequence, and the time-frequency function characteristics of generated code sequences to measure the signal resolution, are considered. And two chaos based QCSK digital communication systems-one with two different chaos code sequences, the other with FFT of one chaos code sequence-are analyzed in AWGN and fading communication channels. After analyzing the correlation functions of such sequences, the delta-like autocorrelation and near zero crosscorrelation functions of them are very suitable for chaos based spread spectrum communication systems, is verified. Through evaluating the performance of two chaos based QCSK systems above using Monte-Carlo simulation, the improvement of performance in the latter QCSK system compare favorably with that of the former system, is shown.

• Journal of the Korea Convergence Society
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• v.8 no.7
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• pp.39-46
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• 2017

Dongguan City of Guangdong province, one of the core areas of the Pearl River Delta, has also pursued economic development through the geographical advantage close to Hong Kong. In the early 1980s, small and medium-sized multinational corporations related to home appliances industry from Hong Kong invested to the Dongguan area and set up a production factory. In the mid-1990s, as Taiwanese PC manufacturers invested, local industrial clusters have developed in Dongguan with core of the IT, PC components and electronic industries. The case of the IT industrial cluster in Dongguan is a typical example of the development of Chinese manufacturing industry after the reform of China. This paper focused on the coupling strategy case of Dongguan City industrial cluster in Guangdong province, and theoretically compared the endogenous growth factor analysis(NMID) of regional industrial development with the regional differentiation of industry based on external linkage with global production network(GPN).

• Journal of Convergence for Information Technology
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• v.10 no.8
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• pp.179-186
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• 2020

The purpose of this study was to investigate the effects on the bio signal of brain waves and pulse waves using acupressure thermal bed combined with acupressure and thermal therapy. Forty healthy adults were divided into 20 experimental groups using combinatorial stimulation beds and 20 non-irritating controls. As a result of the experiment, the EEG was significantly increased in the delta wave and theta wave in the experimental group, and the alpha wave and beta wave decreased significantly. The pulse wave increased the parasympathetic activity index in the experimental group and the heart rate decreased. There was no difference in the control group. This change in EEG can be seen as a combination stimulation bed having a sleep-inducing effect, and a change in pulse wave can seen as having a relaxing effect. This study is expected to be used as basic data for the development of various combination stimulators and functional bed products.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.7
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• pp.1387-1393
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• 2007

Even if the linearly separable patterns can be classified by the conventional single layer perceptron, the non-linear problems such as XOR can not be classified by it. A fuzzy single layer perceptron can solve the conventional XOR problems by applying fuzzy membership functions. However, in the fuzzy single layer perception, there are a couple disadvantages which are a decision boundary is sometimes vibrating and a convergence may be extremely lowered according to the scopes of the initial values and learning rates. In this paper, for these reasons, we proposed an enhanced fuzzy single layer perceptron algorithm that can prevent from vibration the decision boundary by introducing a bias term and can also reduce the learn time by applying the modified delta rule which include the learning rates and the momentum concept and applying the new linear activation function. Consequently, the simulation results of the XOR and pattern classification problems presented that the proposed method provided the shorter learning time and better convergence than the conventional fuzzy single layer perceptron.

• The Korean Journal of Food & Health Convergence
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• v.5 no.2
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• pp.13-25
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• 2019

This study was aimed at ascertaining the level of knowledge of the health effects of cigarette smoking on health and wellbeing among adults. A cross-sectional form of descriptive survey research design was used for this study. Two hundred and seventy copies of the questionnaire collected were analyzed using descriptive statistic of frequency count, normative percentage and grand mean; as well as inferential statistics of chi-square (${\chi}^2$). The level of significant was fixed at 0.05. Appropriate degrees of freedom were worked out. The influence of gender on the knowledge of the negative effect of cigarette smoking among adults in sokoto. The results shows that 48% agreed on the negative effects of showing among male followed by 29.3% among female, those who undecided 8.8% male and 4.4% females while those who disagree are 6.2% for male and 2.5% for female. The research concluded that the knowledge of negative effect of cigarette smoking among adults in sokoto metropolis was very good across the different variable (marital status, gender, and year in higher institution) with single, male and first year in higher institution showing significantly good knowledge of the negative effect of cigarette smoking.

• Journal of the Korea Convergence Society
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• v.10 no.7
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• pp.101-108
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• 2019

Depending on the location of the lung tumor, the choice of treatment technique should be considered when treating the Cyberknife. The 4DCT images of 18 lung cancer patients were analyzed, and location error values were extracted through application program. The evaluation result was lower than the average position error only in the upper and the inner. These results suggest that the Vertebral tracking technique is effective when it is close to the pulmonary attachment or near the vertebral body, and the Synchrony technique is effective at other positions. In the future, we would like to study cyber knife treatment technique according to the position of the tumor as well as the volume of the lung and the respiratory cycle.

• Journal of information and communication convergence engineering
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• v.5 no.2
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• pp.140-143
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• 2007

Fingerprint Recognition System is made up of Off-line treatment and On-line treatment; the one is registering all the information of there trieving features which are retrieved in the digitalized fingerprint getting out of the analog fingerprint through the fingerprint acquisition device and the other is the treatment making the decision whether the users are approved to be accessed to the system or not with matching them with the fingerprint features which are retrieved and database from the input fingerprint when the users are approaching the system to use. In matching between On-line and Off-line treatment, the most important thing is which features we are going to use as the standard. Therefore, we have been using "Delta" and "Core" as this standard until now, but there might have been some deficits not to exist in every person when we set them up as the standards. In order to handle the users who do not have those features, we are still using the matching method which enables us to make up of the spanning tree or the triangulation with the relations of the spanned feature. However, there are some overheads of the time on these methods and it is not sure whether they make the correct matching or not. In this paper, introduces a new data structure, called Union and Division, representing binary fingerprint image. Minutiae detecting procedure using Union and Division takes, on the average, 32% of the consuming time taken by a minutiae detecting procedure without using Union and Division.

• Korean Journal of Materials Research
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• v.28 no.3
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• pp.182-188
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• 2018

Nitrogen (N)-doped protein-based carbon as platinum (Pt) catalyst supports from tofu for oxygen reduction reactions are synthesized using a carbonization and reduction method. We successfully prepare 5 wt% Pt@N-doped protein-based carbon, 10 wt% Pt@N-doped protein-based carbon, and 20 wt% Pt@N-doped protein-based carbon. The morphology and structure of the samples are characterized by field emission scanning electron microscopy and transmission electron micro scopy, and crystllinities and chemical bonding are identified using X-ray diffraction and X-ray photoelectron spectroscopy. The oxygen reduction reaction are measured using a linear sweep voltammogram and cyclic voltammetry. Among the samples, 10 wt% Pt@N-doped protein-based carbon exhibits exellent electrochemical performance with a high onset potential of 0.62 V, a high $E_{1/2}$ of 0.55 V, and a low ${\Delta}E_{1/2}=0.32mV$. Specifically, as compared to the commercial Pt/C, the 10 wt% Pt@N-doped protein-based carbon had a similar oxygen reduction reaction perfomance and improved electrochemical stability.