• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.7
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• pp.1823-1840
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• 2023

In order to improve spectral efficiency and reduce power consumption for reconfigurable intelligent surface (RIS) assisted wireless communication systems, a joint design considering irregular RIS topology, RIS on-off switch, power allocation and phase adjustment is investigated in this paper. Firstly, a multi-dimensional variable joint optimization problem is established under multiple constraints, such as the minimum data requirement and power constraints, with the goal of maximizing the system energy efficiency. However, the proposed optimization problem is hard to be resolved due to its property of nonlinear nonconvex integer programming. Then, to tackle this issue, the problem is decomposed into four sub-problems: topology design, phase shift adjustment, power allocation and switch selection. In terms of topology design, Tabu search algorithm is introduced to select the components that play the main role. For RIS switch selection, greedy algorithm is used to turn off the RISs that play the secondary role. Finally, an iterative optimization algorithm with high data-rate and low power consumption is proposed. The simulation results show that the performance of the irregular RIS aided system with topology design and RIS selection is better than that of the fixed topology and the fix number of RISs. In addition, the proposed joint optimization algorithm can effectively improve the data rate and energy efficiency by changing the propagation environment.

• Journal of Korean Academy of Nursing
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• v.29 no.2
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• pp.258-270
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• 1999

This study was carried out to offer the basic data for more qualitative lives of the middle-aged women through their health maintenance and control. So, the researcher reviewed and analyzed the health problems of the middle-aged women, the differences of main symptoms in each subject, positive ratcs in screening tests, the difference of screening tests with age and the correlation of obesity and blood pressure with screening tests. All subjects were 218 women(40-59years) who had a check-up at a comprehensive health check-up center in K University Hospital in Seoul from July 1, 1998 to August 31. 1998. Questionaires were developed to get subjects, general characteristics. main symptoms, medical examination and diagnosed disease by the researcher referring through the questionaires of comprehensive health check-up center and the medical recorders were used as a tool of study. The researcher analyzed the data with SPSS PC+ ; the distribution of the subjects, general characteristics and main symptoms with percentage : the difference between main symptoms and screening tests with X$^2$-test, ANOVA. The results are as follows. 1) Among the age distribution, most were 40-45 years old and unemployed. 2) The most common complaints were indigestion in digestive system, cough in respiratory system, heart beat in cardiovascular system, general sweat in endocrine system. edema in urinary system, easy bruise in hematologic system, backache in musculoskeletal system, headache in psychoneurologic system, lochia in gynecology, itch in dermatology system, eye ball pain in visual system and tinnitus in auditory system. 3) In main symptoms according to age, the 40-45 age group had a higher rate of complaints in digestive system and gynecology than other age group ; the 46-49 age group in endocrine system. 4) The main symptoms according to diagnosis had no difference statistically. 5) The screening tests which showed high rates of abnormality were mammography(the highest), abdominal ultrasonography, upper gastrointestinal series/gastrofiberscopy, PFT. In all age group the highest rate of abnormality was seen in mammography. 6) In screening tests according to age. the 46-49 age group showed higher positive rates of pap smear, blood sugar test, urine test than any other age group ; the 50-55 age group showerd higher positive rates of obesity, BP, chest X-ray, abdominal ultrasonography, ESR, SGOT, CRP and urine micro. 7) In correlation of obesity with screening test, the obesity group showed higher positive rates of blood pressure, chest X-ray, abdominal ultrasonography, HCT and CRP than the normal weight group. 8) In correlation of blood pressure with screening test, the hypertension group showed higher positive rate of obesity, chest X-ray, abdominal ultrasonography, pap smear and blood sugar than the normal blood pressure group. In conculusion, the middle-aged women have various physical symptoms and affected by age. The obesity and BP have an important effect on the health of the middle aged women. Therefore, this study is considered significant as data for qualitative lives of the middle-aged women playing an important part of family health care by catching of their health problem complaints for prevention of disease and promotion of health.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.58-63
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• 2010

In this paper, we proposed a wearable respiration measurement system with textile capacitive pressure sensor. Belt typed textile capacitive pressure sensor approach of respiration measurement, from which respiration signatures and rates can be derived in real-time for long-term monitoring, are presented. Belt typed textile capacitive pressure sensor has been developed for this measurement system. the distance change of two plates by the pressure of motion has been used for the respiration measurement in chest area. Respiration rates measured with the textile capacitive pressure sensor was compared with standard techniques on 8 human subjects. Accurate measurement of respiration rate with developed sensor system is shown. The data from the method comparison study is used to confirm theoretical estimates of change in capacitance by the distance change. The current version of respiratory rate detection system using textile capacitive pressure sensor can successfully measure respiration rate. It showed upper limit agreement of $3.7997{\times}10^{-7}$ RPM, and lower limit of agreement of $-3.8428{\times}10^{-7}$ RPM in Bland-Altman plot. From all subject, high correlation were shown(p<0.0001). The proposed measurement method could be used to monitor unconscious persons, avoiding the need to apply electrodes to the directly skin or other sensors in the correct position and to wire the subject to the monitor. Monitoring respiration using textile capacitive pressure sensor offers a promising possibility of convenient measurement of respiration rates. Especially, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products. Further advances in the sensor design, system design and signal processing can increase the range and quality of the rate-finding, broadening the potential application areas of this technology.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.3
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• pp.19-26
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• 2017

In this paper, a Linear Error Correction Code, Which is Applicable to Next Generation Wireless Communication System Technology, is Constructed Based on Performance Comparison and Transmission Based on the Premise of High Performance Mobile Rate Enhancement System. This is Because Data Rates are Becoming an Important Issue in Reed-Solomon Codes and Linear Error Code (LDPC) Used in the Physical Layer of Digital Communication and Broadcasting Technologies. Therefore, this paper Simulates the Performance of Reed - Solomon Code and LDPC Applied to Mobile Broadcasting DVB (Digital Video Broadcasting) System and Mobile Broadcasting in Digital Communication and Broadcasting, At this time, Technical Aspects of the Transmission Efficiency and Performance of the LDPC Replacing the Existing Reed-Solomon Code have been Verified from the Viewpoint of Efficiency.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.1
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• pp.20-33
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• 2006

Changing of industry structure and development of traffic and telecommunications requires a change of the knowledge about the space where the human beings reside. Step by step the world is being divided into specified utility blocks. Today there is a limit that only one local government can compete with another region in the world. This study provides decision support tools with the use of GIS on the regional level for regions competition. GIS establishes regions and analyzes their geographic environment data, which will help in local-government problem solving and provide framework data for similar regions to become the community. The wide-area GIS application can present an objective and rational basis for regulation of inefficient investments and excessive competition between adjacent regions. The study area is Gangwon-do. Considering specific features of Gangwon-do which preserved high-quality environment resources, river basins were taken as a basis among natural regional elements. The main object of analysis conducted were the facts relevant to environmental regulation. The Gangwon-do consists of three regions in this study: Yongdong region, North-Hangang region and South-Hangang region. The analysis of each region regulation cases showed the following: in Youngdong region the forests regulation rate is high, in North-Hangang region the military installations protection sector's rate as well as regulation rate for water resources protection is relatively high, in South-Hangang region the forest and water resources regulation rate is high. The percentage of forests and water regulation rate appeared to be rather high in Gangwon-do, which means that the value of forest and water resources there is very high.

• Child Health Nursing Research
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• v.8 no.2
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• pp.129-140
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• 2002

The article reports the process, contents and strategies in the development of community based-heath care management program for high-risk infants and family, which was based on literature review, empirical needs assessment from pilot study. The program was divided into two emphasis areas: (1) identification and home visiting nursing care program, and (2) the construction of self-supporting group. The contents of home visiting nursing care were developed from the pilot study of the direct home visiting to premature infants after discharge. The documentation form for home care was standardized, including the demographic data, birth history, home care services, education and counsels, and visiting schedules. The integrated education protocol was elaborated to enhance the body of knowledge as well as clinical competency in caring high-risk infants and family by the supports of neonatologists, nursing scholar, and clinical specialists. In addition, the process and strategies in developing self-supporting group, consisting the high-risk infants and family, and any significant others were addressed. Emphases were given to the role of public health center and the recycling health care referral system to maximize the growth and development of high-risk infants on the community-base, which in turn, contributing to decrease the postneonatal mortality rate.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.391-400
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• 2016

In satellite operations, stable maneuvering of a satellite's onboard antenna to prevent undesirable vibrations to the satellite body is required for high-quality high-resolution images. For this reason, the onboard antenna's angular rate is typically minimized while still satisfying the system requirement that limits the speed of the onboard antenna. In this study, a simple yet effective method, called the ground station searching method, is proposed to reduce the angular rate of a satellite's onboard antenna. The performance of the proposed method is tested using real flight data from the KOMPSAT-3 satellite. Approximately 83% of arbitrarily selected real flight scenarios from 66 test cases show reductions in the onboard antenna's azimuth angular rates. Additionally, reliable solutions were consistently obtained within a reasonably acceptable computation time while generating an onboard antenna tracking profile. The obtained results indicate that the proposed method can be used in real satellite operations and can reduce the operational loads on a ground operator. Although the current work only considers the KOMPSAT-3 satellite as a test case, the proposed method can be easily modified and applied to other satellites that have similar operational characteristics.

• Journal of The Korean Society of Integrative Medicine
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• v.4 no.4
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• pp.77-82
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• 2016

Purpose: The purpose of this study was to investigate the therapeutic effect of non-invasive vagus nerve stimulation by transcutaneous electrical nerve stimulation application on the autonomic nervous system of human body. Methods: Participants were seventeen healthy adults. Standard deviation of all normal N-N intervals(SDNN), root mean square of successive differences(RMSSD), low frequency(LF), high frequency(HF) were compared in pre and post Mean values after intervention. Data were analyzed in Wilcoxon's signed-ranks test. Results: The results of this study is that sistolic blood pressure and pulse rate decreased mean value after non-invasive vagus nerve stimulation by transcutaneous electrical nerve stimulation. High frequency, low frequency, SDNN, RMSSD increased mean value in heart rate variability after intervention. But that is not significant except for SDNN. Conclusion: Non-invasive vagus stimulation by transcutaneous electrical nerve stimulation effect on parasympathetic nerve stimulation, and then it might be effective method for autonomic nerve balance control.

• Journal of Broadcast Engineering
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• v.15 no.4
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• pp.547-554
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• 2010

In this paper, we propose transmission systems for ultra high definition television (UHDTV) through terrestrial transmission by applying the multi-input multi-output (MIMO) technology. The space time block code, hybrid STBC, V-BLAST and linear dis- persion code are considered to support a high data rate of the UHDTV system. The performance of proposed MIMO systems are evaluated through computer simulations. Then we suggest MIMO parameters, number of antennas and optimal transmission scheme to achieve the transmission rate of the UHDTV system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.2908-2924
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• 2019

Multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) is widely applied in wireless communication by virtue of its excellent properties in data transmission rate and transmission accuracy. However, as a major drawback of MIMO-OFDM systems, the high peak-to-average power ratio (PAPR) complicates the design of the power amplifier at the receiver end. Some available PAPR reduction methods such as selective mapping (SLM) suffer from high computational complexity. In this paper, a low-complexity SLM method based on active constellation extension (ACE) and joint space-time selective mapping (AST-SLM) for reducing PAPR in Alamouti STBC MIMO-OFDM systems is proposed. In SLM scheme, two IFFT operations are required for obtaining each transmission sequence pair, and the selected phase vector is transmitted as side information(SI). However, in the proposed AST-SLM method, only a few IFFT operations are required for generating all the transmission sequence pairs. The complexity of AST-SLM is at least 86% less than SLM. In addition, the SI needed in AST-SLM is at least 92.1% less than SLM by using the presented blind detection scheme to estimate SI. We show, analytically and with simulations, that AST-SLM can achieve significant performance of PAPR reduction and close performance of bit error rate (BER) compared to SLM scheme.