• Journal of Biomedical Engineering Research
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• v.29 no.3
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• pp.249-253
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• 2008

The indirect-contact ECG (IDC-ECG) was introduced by a prior study for daily non-intrusive measurements. To improve the signal quality and to extend the application area of IDC-ECG, close study of the frequency characteristics of the IDC-ECG is necessary. In this study, the frequency response of the active electrode for several sample clothes was measured under conditions of actual IDC-ECG measurement with human body. Higher gain in low frequency range than expected by prior study was observed. In addition to it, wide variation in gain according to the cloth type in the low frequency range was observed. Variation in gain caused by moisture variation in the clothes was also observed. This study shows that the parallel R-C connection is proper for electrode model and the resistive factor is influenced by moisture in the clothes. This study is the first that provides the frequency response of the electrode in the actual indirect-contact ECG measurement and it is expected that the results will be helpful to improve the indirect-contact ECG method.

• ETRI Journal
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• v.41 no.3
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• pp.383-395
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• 2019

Clock Controlled Dual keeper Domino logic structures (CCDD_1 and CCDD_2) for achieving a high-speed performance with low power consumption and a good noise margin are proposed in this paper. The keeper control circuit comprises an additional PMOS keeper transistor controlled by the clock and foot node voltage. This control mechanism offers abrupt conditional control of the keeper circuit and reduces the contention current, leading to high-speed performance. The keeper transistor arrangement also reduces the loop gain associated with the feedback circuitry. Hence, the circuits offer less delay variability. The design and simulation of various wide fan-in designs using 180 nm CMOS technology validates the proposed CCDD_1 and CCDD_2 designs, offering an increased speed performance of 7.2% and 8.5%, respectively, over a conventional domino logic structure. The noise gain margin analysis proves good robustness of the CCDD structures when compared with a conventional domino logic circuit configuration. A Monte Carlo simulation for 2,000 runs under statistical process variations demonstrates that the proposed CCDD circuits offer a significantly reduced delay variability factor.

• International Journal of Advanced Culture Technology
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• v.10 no.2
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• pp.220-224
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• 2022

The efficiencies of rates and energy in the fifth generation (5G) wireless channels can be improved via intelligent reflecting surface (IRS) transmissions, towards the sixth generation (6G) mobile communications. While previous works have considered mainly optimizations of IRS transmissions, we propose a performance analysis on the total power in terms of the number of reflecting devices for IRS transmissions in non-orthogonal multiple access (NOMA) networks. First, we derive an analytical expression of the total power gain factor in terms of the number of reflecting devices for the cell-edge user in IRS-NOMA systems. Then we evaluate how many reflecting devices we need to obtain a total power gain in dB. Moreover, we also demonstrate numerically the signal-to-noise ratio (SNR) gain of the IRS-NOMA system over the conventional NOMA system based on the achievable data rate.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.9-16
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• 2013

Long term evolution (LTE) and LTE-Advanced (LTE-A) systems adopt closed-loop multiple-input multiple-output antenna techniques. Equal gain transmission which has equal gain property is the key factor in their codebook design. In this paper, a novel differential codebook structure which maintains the codebook design requirements of LTE or LTE-A systems. Especially, eight-phase shift keying (8-PSK) constellations are used as elements of codewords, which not only maintain equal gain property but also reduce the computation complexity of precoding and decoding function blocks. The equal gain property is very important to uplink because the performance of uplink is very sensitive to the peak-to-average power ratio (PAPR). Moreover, the operation of the proposed differential codebook is explained as a rotation-lock structure. As the results of computer simulations, the steady-state throughput performance of the proposed codebook shows at least 0.9dB of SNR better than those of the conventional LTE codebook with the same amount of feedback information.

• Journal of Korean Academy of Nursing
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• v.26 no.1
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• pp.53-72
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• 1996

The Purpose of this study was to identify characteristics of fatigue and the relationship between fatigue and related factors in patients on hemodialysis. This study was a survey study using a cross-sectional design. The subjects for this study were 101 patients on hemodialysis who were registered in the six hemodialysis clinics among a total of eleven clinics in Seoul. The period of data collection was from February 28, 1995 to May 2, 1995. Data were collected through an interview with a structured packet and the physiological data. The tools used in this study were the Visual Analogue Scale-Fatigue developed by Lee et al(1990) and translated by Lee(1991), the fatigue interview schedule developed by this researcher, Zung's self rating depression scale(Zung, 1965), the self-efficacy scale developed by Sherer et al(1982) and the Norbeck Social Support Questionnaire(NSSQ) translated by Oh(1984). The collected data were analyzed using descriptive statistics(mean, standard deviation, frequency, range), Pearson correlation coefficients and Stepwise multiple regression. The results were as follows ; 1. Characteristics of Fatigue of hemodialysis patients : 1) 79 of 101 hemodialysis patients complained fatigue. 2) The mean fatigue score as measured by the VAS-F was 36.2mm. 3) The mean duration of fatigue was 2.9 hours 2. Characteristics of fatigue related factors : 1) The physiologic factor which included Hgb, Hct, BUN, creatinine, potassium and interdialytic weight gain deviated from normal range. 2) The psychological factor which included depression and self-efficacy was about the same level as for patients with other chronic diseases. 3) The environmental factor which included social support had wide variation. 3. The relationship between fatigue and related factors : 1) Interdialytic weight gain in the physiologica factor was the only valuable with fatigue （p＜.05） 2) The relationship between fatigue and the psychological factor of depression showed a positive and strong correlation（p＜.05）. According to the findings of this study, fatigue was highly correlated with the depression. This indicates that nurses should try to assess and control psychological factors when patients complain of fatigue rather than just considering physiological factors. Nursing has to develop effective nursing interventions to reduce fatigue in patients with chronic diseases using the relationship between fatigue and physiological, psychological and environmental factors.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.1
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• pp.90-97
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• 2017

In this paper, we propose a new array antenna scheme which has an improved side lobe level (SLL) as well as a simplified feeding network and a high gain. The proposed array scheme is based on a non-uniformly excited sub-array. For analysis, we use an array factor of sub-array antenna. In the simulation results, the simulated SLL and gain provide more than 18.43 dB and 26.63 dBi, respectively. For the verification of the proposed design scheme, the prototype antenna with $16{\times}8$ radiating elements was designed by the proposed array scheme. The measured SLL and gain are more than 19.85 dB and 25.53 dBi, respectively. This measurement result indicates that the proposed array scheme is reasonable.

• Asian Journal of Innovation and Policy
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• v.6 no.3
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• pp.274-294
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• 2017

While studies have viewed the effect of Chinese talent-attracting programs launched by government since reform and open door policy, little of them has assessed these programs empirically and pertinently. This article intends to assess an important program - the Thousand Youth Talents Program (TYTP). Frist, this paper proposed a transnational migration matrix of the academics to clarify the dynamic mechanism of academic brain gain at the high end. Then, the Kaplan-Meier analysis and Cox regression model are used to empirically analyze the policy effect of TYTP. The results show that, academic ability have double edged impacts on brain gain at the high end, some scholars whose last employer's academic ranking is world's Top100 have stronger willing to return, and the negative effect of academic ranking decreases with time passing; while scholars with a tenure-track position, a tenure position or a permanent position tend to stay overseas, and the hazard rate of staying increases with age. The older scholars have more intentions to go back China, while gender was not a significant factor influencing academic return at the high end. That is, the talent-attracting programs has partly succeeded in bringing back the academics at the high end.

• Proceedings of the KOSOMBE Conference
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• v.1991 no.11
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• pp.44-47
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• 1991

There exists a transform trellis code that is optimal for stationary Gaussian sources and the squared-error distortion measure at all rates. In this paper, we train an asymptotically optimal version of such a code to obtain one which is matched better to the statistics of real world data. The training algorithm uses the M-algorithm to search the trellis codebook and the LBG-algorithm to update the trellis codebook. To adapt the codebook for the varying input data. we use two gain-adaptive methods. The gain-adaptive scheme 1, which normalizes input block data by its gain factor, is applied to images at rate 0.5 bits/pixel. When each block is encoded at the same rate, the nonstationarity among the block variances leads to a variation in the resulting distortion from one block to another. To alleviate the non-uniformity among the encoded image, we design four clusters from the block power, in which each cluster has its own trellis codebook and different rates. The rate of each cluster is assigned through requiring a constant distortion per-letter. This gain-adaptive scheme 2 produces good visual and measurable quality at low rates.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.2
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• pp.195-203
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• 2016

In order to overcome the influence of system stability and accuracy caused by uncertainty, estimation errors and external disturbances in Eight-Rotor MAV, L2 gain control method was proposed based on interval type II fuzzy neural network identification here. In this control strategy, interval type II fuzzy neural network is used to estimate the uncertainty and non-linearity factor of the dynamic system, the adaptive variable structure controller is applied to compensate the estimation errors of interval type II fuzzy neural network, and at last, L2 gain control method is employed to suppress the effect produced by external disturbance on system, which is expected to possess robustness for the uncertainty and non-linearity. Finally, the validity of the L2 gain control method based on interval type II fuzzy neural network identifier applied to the Eight-Rotor MAV attitude system has been verified by three prototy experiments.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.298-302
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• 2008

We have developed a 270-W 15-kHz MOPA system based on side-pumped rod-type Nd:YAG gain modules. The master oscillator is a 3-W 15-kHz $TEM_{00}$ $Nd:YVO_4$ laser with a pulse duration of 30 ns. To preserve the high beam quality during the amplification, we use image relay and polarization rotation which can simultaneously compensate for thermal lensing and thermal birefringence generated in the rod-type gain modules. After the amplification to 270 W with six rod-type gain modules, the beam quality factor ($M^2$) of the amplified laser beam is 5-10, and the pulse duration is maintained at 30 ns.