• 대한물리치료과학회지
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• 제28권3호
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• pp.76-87
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• 2021

Background: The purpose of this study was to evaluate the effects of power walking and square dancing on middle-aged women with hypertension. Design: Randomized controlled Trial. Methods: 30 middle-aged women with hypertension were selected and divided into two groups. 15 cases in the control group received routine treatment, and 15 cases in the intervention group received community vigorous walking and square dancing intervention on the basis of routine treatment. The intervention time was 40-60minutes/day, 5days/week, total 16 weeks. total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL), angiotensin II (Ang II), Leptin, blood pressure, and heart rate were measured. Results: Body weight, body mass index (BMI), TC, TG, LOW-density lipoprotein, angiotensin II, leptin, systolic blood pressure and heart rate were significantly reduced after power walking and square dancing (p<0.05). After the experiment, TC and TG in the experimental group were lower than those in the control group (p<0.05), while HDL was higher (p<0.05). Conclusion: The results of this study suggest that power walking exercises and square dances are significant effects on lipid mechanism and heart rate.

• 한국ITS학회 논문지
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• 제8권6호
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• pp.64-72
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• 2009

본 논문에서는 마이크로스트립 패치 안테나와 2차 및 3차 고조파가 억압된 이중모드 대역통과 여파기를 이용하여 고효율의 2.45 GHz 렉테나를 설계 및 제작하였다. 입사전력밀도가 0.3 mW/cm2 일 때 1.66 mW 의 전력을 수신하였고, 41.6%의 RF-to-DC 변환효율의 실험 결과를 얻었다. 이는 입사 전력이 작기 때문에 다른 논문의 결과와 비교하여 고효율이라고 볼 수 있다. 또한 무선전력 전송을 통하여 다양한 응용기술 개발에 활용이 가능할 것으로 예측되며, USN(Ubiquitous Sensor Network)용 저전력 소자의 대기전원 공급 및 MEMS용 Sensor 등의 구동전압공급을 위한 무선 전력전송이 가능하게 될 것으로 기대된다.

• ETRI Journal
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• 제26권5호
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• pp.375-383
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• 2004

This paper proposes a common interleaving method associated with independent channel-encoding among transmitter antenna branches in orthogonal frequency and code division multiplexing based on multiple-input multiple-output (MIMO) multiplexing to achieve an extremely high throughput such as 1 Gbps using a 100 MHz bandwidth. This paper also investigates the average packet error rate performance as a function of the average received signal energy per bit-to-background noise power spectrum density ratio $(E_b/N_0)$. We found that the loss in the required average received $E_b/N_0$ of the proposed method is only within approximately 0.3 dB in up to a 12-path Rayleigh fading channel, using 16QAM and Turbo coding with a coding rate of 5/6. We also clarify that even for a large fading correlation among antenna branches, 1 Gbps is still possible by increasing the transmission power. Therefore, the proposed method reduces the processing rate to 1/4 in the turbo decoder with only a slight loss in the required average received $E_b/N_0$.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1701-1704
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• 2002

In this paper, we investigate the effect of power control step size on the performance of the SIC scheme in DS/CDMA systems. We investigate the average power control iteration and its standard deviation and evaluate the outage performance for several different values of power control step size. Because the SIC scheme requires fine control in the received signal power, the better outage performance is obtained fer the smaller power control step size. However, the smaller power control step size requires larger amount of power control iteration in order to make the power control converge to the steady state. Under the simulated environment, the proper power control step size is about 0.3-0.4dB from both convergence speed of power control algorithm and outage performance points of view.

• ETRI Journal
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• 제27권3호
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• pp.267-272
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• 2005

The transmission performance of optical labeling based on a combined frequency shift keying/amplitude shift keying (FSK/ASK) format is studied by numerical simulation. The simulation demonstrates that the bit-error ratio (BER) characteristic of an ASK signal is limited by the extinction ratio, received optical power, and dispersion, simultaneously. However, an FSK signal is mainly limited by the extinction ratio (ER) and received optical power when the peak spectrum, which is used to detect the FSK signal, is relatively narrow.

• Nuclear Engineering and Technology
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• 제52권9호
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• pp.2041-2046
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• 2020

The present article investigates the influence of hydrogen concentration on the creep performance of cold-worked stress-relieved unirradiated Zircaloy-4 cladding tube using nanoindentation technique. The as-received Zircaloy-4 tube is hydrided to the concentrations of 600 ppm and 900 ppm using gaseous hydrogen charging method. Constant load indentation creep tests are performed for a dwell period of 600 s in the temperature range of 300℃-500 ℃ at 1000 μN, 2000 μN, and 3000 μN. The impact of hydrogen is evaluated in terms of steady state power law creep exponent and activation energy. The power law creep exponent decreases with increase in hydrogen concentration, however, it remains fairly constant with increase in temperature up to 500 ℃. Moreover, activation energy too decreases significantly with increase in hydrogen concentration. The mean stress exponent and activation energy are found to be 3.58 and 28.67 kJ/mol, respectively, for as-received sample.

• 전기학회논문지P
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• 제60권4호
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• pp.200-205
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• 2011

In multipath fading channel, diversity is essential to mitigate the impairments. In this paper, we have proposed the angle diversity scheme called ATTD(Angle Time Transmit Diversity) instead of Alamouti's STTD(Space Time Transmit Diversity) and have analyzed the performance of the proposed scheme when signal powers caused by the transmission to different angles are different. Based on it, we have measured the wireless vector-channel in the urban area, which has lots of high-story buildings, using the data collected from the 8 by 4 smart array antenna system that we made. According to the measured data, the received signals from different angles have different signal powers. Our performance analysis results show that the proposed scheme has better performance than the space diversity scheme when the received path signal power is at least -7dB compare to the strongest path signal power.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1998년도 학술발표대회 논문집 제17권 2호
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• pp.133-136
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• 1998

The aim of the work described in this paper is to develop a complex underground acoustic system which detects and locates the origin of an underground hammering sound using an array of six hydrophones located about 100m underground. Two different methods for the sound localization will be presented, a time-delay method and a power-attenuation method. In the time-delay method, the cross correlation of the signals received from the array of sensor sis used to calculate the time delays between those signals. In the power-attenuation method, the powers of the received signals provide a measure f the distances of the source from the sensors.

• 전자공학회논문지A
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• 제33A권2호
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• pp.15-22
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• 1996

This paper presents the generalized method of the prediction of the LOS propagating characteristics in an urban microcell by using theray tracing technique. Whereas the received power is calculated by the finite number of pths, 4~10, on an urban steet, the RMS delay spread is comuted by using the sufficient rays of convergence. To take into account the infinite number of paths the technique of the numbering scheme of image antennas was presented by using the rectangular pulse. As to this the existing restriction of the finitte number of paths was relaxed. based on the method of extending the number of paths and the canyon model the received power and RMS delay spread are computed and their differences according to the number of paths are compared at the frequencies of both 1GHz and 2GHz, respectively.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.138-148
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• 1998

The aim of the work described in this paper is to develop a complex underground acoustic system which detects and localizes the origin of an underground hammering sound using an array of hydrophones located about loom underground. Three different methods for the sound localization will be presented, a time-delay method, a power-attenuation method and a hybrid method. In the time-delay method, the cross correlation of the signals received from the way of sensors is used to calculate the time delays between those signals. In the power-attenuation method, the powers of the received signals provide a measure of the distances of the source from the sensors. A new hybrid method has been developed for estimating the origin of the underground acoustic source by coupling both methods. The Nelder-Meade simplex search algorithm is then used to numerically estimate the position of the source in those methods. For each method the sound localization is carried out in three dimensions underground. The distance between the true and estimated origins of the source is in some cases less than 6m for a search area of radius 250m.