• Title/Summary/Keyword: frequency effect

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Multi-stage and Variable-length Peak Windowing Techniques for PAPR Reduction of OFDMA Downlink Systems (OFDMA 하향링크 시스템에서의 PAPR 저감을 위한 다단계 및 가변길이 첨두 윈도윙 기법들)

  • Lee, Sung-Eun;Min, Hyun-Kee;Bang, Keuk-Joon;Hong, Dae-Sik
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.2
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    • pp.67-74
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    • 2008
  • This paper proposes two peak-windowing algorithms for peak-to-average power reduction(PAPR) of orthogonal frequency division multiple access(OFDMA) downlink systems. The Proposed algorithms mitigate the effect of excessive suppression due to successive peaks or relatively high peaks of the signal. First, multi-stage peak windowing algorithm is proposed, which exploits multiple threshold of target PAPR in order to step down the peaks gradually. Secondary, variable-length peak windowing algorithm is proposed, which adapts the window length with respect to the existence of successive peaks within a half of window length. Therefore, the proposed method reduces the distortion of signal amplitude caused by window overlapping. The proposed algorithms outperform the conventional peak windowing with the aid of window-length adaptation or sequential peak power reduction. Simulation results show the efficiency of the proposed algorithms over OFDMA downlink systems, especially WiBro systems.

Effects of Oral Health Education Program on the Oral Health Knowledge, Oral Health Behavior and Oral Hygiene Status of Elementary School Students (구강보건교육 프로그램이 초등학생의 구강보건지식, 구강보건행위 및 구강위생 상태에 미치는 효과)

  • Son, Mi-Hyang
    • Research in Community and Public Health Nursing
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    • v.14 no.1
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    • pp.24-35
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    • 2003
  • The purpose of this study was to evaluate the effects of oral health education program on the oral health knowledge, oral health behavior and oral hygiene status of elementary school students. The design of this study is nonequivalent control group pretest-posttest gesign. Data was collected between the 17th of June and 13th of July in 2002, and the Experimental group were 131 students of Y Elementary School. which was one of the two elementary schools in K City, Gyeongsangbuk-do, and the control group was 140 students of C Elementary School, which was similar to Y Elementary School in geographical and economical properties and size. As for research tools, the researcher developed tools of measuring oral health knowledge and oral health behavior by modifying the tools developed by Hye-Kyong Kim (2001), In-hyang Seo (1988), Ho-Youn Lee (2001), Hyeon-ja Jeon (1998). To measure oral hygiene status. the researcher applied a coloring agent to the surface of the teeth after brushing, rinsed the mouth, and calculated colored plaque on the surface of the teeth, which was recorded on a sheet and analyzed using the plaque index. The data analysis was done using frequency, percentage, mean, standard deviation, Chisquare test, t-test, ANCOVA, Two-way ANOVA, Simple main effects, One-way ANOVA, and Duncan. Using with SPSS WIN 10.0. The result of this study are summarized as follows: 1. The hypothesis was supported 'The elementary school students which was given oral health education program will shows higher oral health knowledge, oral health behavior, oral hygiene status then control group' 2. According to the result of verifying the hypothesis, 'The effect of oral health education program will be different between junior and senior' the hypothesis was partly supported To summarize result of this research, the experimental group, to which oral health education was given, was improved in oral health knowledge, oral health behavior and oral hygiene status compared to the control group, so the oral health education program was effective for the oral health of elementary school students.

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Reception Performance Improvement of the Long-Haul WDM System with the Channel Interference Due to FWM Effect through the Power Symmetric Mid-Span Spectral Inversion (FWM에 의한 채널 간섭이 존재하는 장거리 WDM 시스템에서의 전력 대칭 MSSI 보상법을 통한 수신 성능 개선)

  • 이성렬;장원호;이윤현
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.7
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    • pp.716-725
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    • 2002
  • In this paper, we showed the applicability of power symmetric MSSI(Mid-Span Spectral Inversion) to the long-haul WDM system with the channel interference due to FWM(Four Wave Mixing). And we showed the degree of performance improvement. We used 1 dB EOP(Eye-Opening Penalty) criterion so as to evaluate the degree of compensation dependent on the variation of chirp parameter of optical pulse for the various input power in high speed tansmission system. And we evaluated the maximum input power of channel be able to be the signal to crosstalk noise (SNR) above 20 dB in the transmission link with the channel interference due to FWM. Consequently the proposed MSSI compensation method is capable to transmitting the total 68 WDM channels simultaneously with a 0.4 nm channel spacing and 5.3 dBm maximum input power in a 10 Gbps transmission link. Therefore the proposed power symmetric MSSI compensation method may be very useful for the implementation of long-haul wideband WDM transmission systems with relatively high power and improved performance.

The Effects of Static Magnetic Field and Pulsed Electromagnetic Field on Alkaline Phosphatase and DNA synthetic Activity of ME3T3-E1 Cells (정자기장과 맥동전자기장이 MC3T3-E1 세포의 ALP 및 DNA 활성도에 미치는 영향)

  • Son, Jeong-Hee;Bae, Seong-Min;Sung, Jae-Hyun
    • The korean journal of orthodontics
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    • v.27 no.4 s.63
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    • pp.623-632
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    • 1997
  • The purpose of this study was to evaluate the effects of magnetic field on cellular activity of MC3T3-E1 cells. The cellular activity was monitored by alkaline phosphatase and DNA synthetic activity in control, static magnetic field and pulsed electromagnetic field groups. A static magnetic field was applied to the cell by placing one, two, three, foue, and five samarium-cobalt magnets above and below each cell plate for 24hours per day. A pulsed electromagnetic field with a frequency of 100 herz was applied for 10 hours per day. After 10 days of magnetic field exposure, there were increase of alkaline phosphatase activity in static magnetic field groups consisted of one, two and three magnetic groups. Alkaline phosphatase activities were not significantly increased in four and five magnetic groups. Application of pulsed electromagnetic field did not result in significant increase in alkaline phosphatase activity compared to control. DNA synthetic activity in both static and pulsed electromagnetic field group were not significantly different from that in control group. The result of this study suggest that magnetic field could have effect on the metabolism of bone cells related to the cellular metabolic process.

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Consumption of Instant Coffee Mix and Risk of Metabolic Syndrome in Subjects that Visited a Health Examination Center in Gwangju (광주 지역 건강검진센터를 내원한 수진자의 인스턴트 커피믹스 섭취와 대사적 위험요인과의 연관성)

  • Kim, Kyoung Yun;Yang, Soo Jin;Yun, Jung-Mi
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.46 no.5
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    • pp.630-638
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    • 2017
  • Metabolic syndrome is associated with risk of developing cardiovascular disease and type 2 diabetes, and incidence of metabolic syndrome is showing an increasing trend. Recently, coffee intake is argued to have an effect on the gut-brain axis, and it is widely recognized has being associated with many beneficial effects, including those related to metabolic imbalance. However, it is essential to understand how the dietary aspects of coffee intake and type of coffee intake affect diet and overall health. The association between coffee consumption and health is still controversial, and the average body weight of the Korean population is increasing. Therefore, this study focused on analyzing the effects of instant coffee (particularly instant coffee mix) in Korea, especially with respect to metabolic syndrome. The study was conducted on participating subject's that visited Sun-Han hospital, and instant coffee mix intakes and metabolic risk factors during the study period were examined from July 2015 to June 2016. The results showed that waist circumference (r=0.405, P=0.036) and serum triglyceride level (r=0.435, P=0.023) were positively correlated with instant coffee mix intakes. In addition, instant coffee mix intakes were significantly associated with serum triglyceride level in subjects who consumed more than 1 cup/d of coffee (P<0.05). Therefore, subjects should be careful about fat intake and be educated about the type and frequency of coffee intakes.

Improvement Effects of Cement Grouting using Vibration Method through a Field Test (현장시험을 통한 시멘트 진동주입공법의 보강효과)

  • Han, Sanghyun;Yea, Geugweun;Kim, Hongyeon
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.5
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    • pp.23-29
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    • 2014
  • So far, the grouting using pressure injection has been extensively used to avoid adverse effects such as soil disturbance. Whereas, the pressure injection to the limitations of the diffusion range, so that the kinks would last injection of cement particles by introducing a frequency oscillation effect improved injection method have been recently developed. In this study, a pilot test was performed to compare injection effects of the both methods. The injections using both methods were tested on the embankment which consists of core clay and weathered soil. Subsequently, the injected volume, SPT N values, in-situ permeability and electrical resistivity were measured to compare their effects. The vibration method showed more effective permeation comparing with the pressure method. Also, it showed more homogeneously improved ground than the existing method. For SPT results, the vibration method presented increase of mean N value as much as 17.4 % comparing with the conventional method. Higher electrical resistivity was presented in case of injecting with vibration method and it indicated the injection was extensively completed. Finally, it is expected that the economic feasibility will be improved by decrease of drilling spacing, when the existing method is replaced with vibration method.

The Effect of Self-esteem, Academic Achievement and Family Functioning of Adolescents on Hope (일도시 청소년의 자아존중감, 학업성취수준, 가족기능이 희망에 미치는 영향)

  • Lee Jong Eun;Park Sun Nam;Park Ho Ran
    • Child Health Nursing Research
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    • v.7 no.1
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    • pp.74-84
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    • 2001
  • This study is the descriptive survey for the purpose of providing the basic data that establishes the strategy to promote adolescent's hope by the examining of self-esteem, academic achievement, family functioning and hope of adolescents and the investigating of the factors influencing the hope in adolescents. The subjects for this study were 456 students of the first and second year of man's senior high school that located in Seoul. The data were gathered from 16th to 31st of the October 2000. For the survey tool, it was used that the Family Assessment Device(FAD) of Epstein, Baldwin & Bishop(1983), the Self-Esteem Inventory(SEI) of Coopersmith(1975), the class record order and Hinds & Gatusso(1991)'s Hopefulness Scale for Adolescents(HSA). The collected data was analyzed by statistics methods as the descriptive and frequency analysis, t-test, ANOVA, Pearson and Spearman correlation coefficients and Stepwise multiple regression of SAS program. The results of this study were following : 1. The mean score of self-esteem of young people was 51.06±6.83 and the mean grade was 2.04. The high academic achievement was 29.2%, middle grade was 52.7%, and low grade was 18.1%. The mean score of the family functioning was 38.30±6.98 and the mean grade was 2.25. The mean score of hope was 84.26±16.45 and the mean grade was 3.51. 2. The hope in adolescents was significantly different according to their father's school career. The mean score of the group that the father's school career was below junior high school was 77.32. That was significantly lower than the mean score 84.59 of the group that the father's school career was above college and the mean score 85.18 of senior high school group(F=4.04, P= 0.0183). 3. The self-esteem was represented the positive correlation with family functioning(r=0.43) and the all of the 4 subscales(r=0.31, 0.41, 0.39, 0.30). And, it was highly ranked as much as family functioning was good. The academic achievement was represented the positive correlation with self-esteem(r= 0.15). Also, the positive correlation was shown between the affective responsiveness, role recognition and emotional support as the subscales of family functioning and academic achievement(r=0.11, 0.12). And so, academic achievement was high as much as self-esteem was high and affective responsiveness and role recognition and emotional support were good. The hope was represented positive correlation with self-esteem and academic achievement(r=0.42, 0.26), and with the whole of family functioning(r=0.15) and the 4 subscales(r=0.13, 0.16, 0.11, 0.13). So, hope was high as much as self-esteem was high, academic achievement was high and family functioning was good. 4. The influencing factors on the hope of adolescents were self-esteem(17.63%), academic achievement(3.41%), father's school career(0.84%). These factors made it possible to explain 21.88% of hope.

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Alcohol Expectancies in Relation to their Drinking Practices among Korean High School Students (음주효과에 대한 기대와 한국 고등학생들의 음주행위간 관계)

  • Yoon, Hye-Mee;Kim, Yong-Seok;Jang, Seung-Ock
    • Korean Journal of Social Welfare
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    • v.38
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    • pp.153-179
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    • 1999
  • Despite the enforcement of minimum legal drinking age of 18 years of age since 1997, alcohol experimentation among Korean youth is believed to be greater than ever before. The use of alcohol jeopardizes physical, mental, and social development during a person's formative years, thereby endangering successful transitions from adolescent to adulthood. Even infrequent use of alcohol may result in intoxication and acute consequences, especially among youth, who may have low tolerance due to their smaller body size and may lack experience with the effects of alcohol. Using self-report questionnaire data collected from 1,697 highschool students nation-wide, the drinking behavior among Korean high school students and the relation between adolescents' alcohol expectancy and adolescent alcohol use patterns were examined. Results indicated that gender and the type of school(academic or vocational) were significant effects on the drinking behavior(drinking frequency, experience of drunkenness, the amount of alcohol consumed, experience of binge drinking and that of problems due to drinking). Male students than female students, and students of vocational schools rather than those of academic high schools reported more alcohol experimentation. Also, positive alcohol expectancy proved to have a significant relation with alcohol use among high-school students. That is, students who reported to think alcohol would have a positive effect on socializing, aggressiveness, relaxation of tensions, and enforcing sexual ability tended to drink more, to experience more binge drinking and more drinking problems. Variables of gender and the type of school also were found to have significant effects on alcohol expectancy. Males and students of vocational school held ideas of positive outcomes on drinking than others. Implications for further study on developing prevention programs are presented.

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A Study on the Types of Residential Mobility in the Households of Public Rental Housing: Focused on Those Who Moved Out from National Rental Housing in Cheongju (공공임대주택가구의 주거이동 유형에 관한 연구: 청주시 국민임대주택 퇴거자를 중심으로)

  • Ko, Jung-Hee
    • Korean Journal of Social Welfare
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    • v.61 no.2
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    • pp.33-60
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    • 2009
  • This study aimed at examining whether the national rental housing supplied by Korea National Housing Corporation (KNHC) is truly contributing to the upward mobility of housing in low-income households without their own house by comparatively analyzing whether those who moved out of the national rental housing made upward, horizontal or downward housing type mobility. The subjects of this study included 333 people who had moved out of three national rental housing complexes in Cheongju, Chungcheongbuk-do in 2007, which had opened to the first residents two years ago. A telephone survey involving the subjects was carried out. Collected data were analyzed through frequency analysis, cross tabulation analysis and multiple regression analysis, with using the type of residential mobility(downward mobility, horizontal mobility or upward mobility) according to "housing size" and "housing costs" as a dependent variable, and personal and family environment and economic environment as independent variables. According to the results of the analysis, 76.4% of the households made an upward mobility, 1.6% remained little changed, and 22% moved downward in terms of "housing costs," compared to before moving into the national rental housing and while living there. Furthermore, in terms of "housing size" 61.8% of the households moved upward, 16.5% remained little changed and 19.7% moved downward. The variables affecting the upward mobility of housing type included the number of income earners in a household, income earner's occupation and education level. Income earner's amount of income, age and family to support, on the other hand, turned out to have little effect on the upward mobility. Based on the results of the study, the following suggests were made for the supply of effective national rental housing. First, various features of each type of residential mobility should be reflected. Second, national rental housing residents' self-sufficiency should be enhanced to help them move upward in housing type.

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A Study on the Home Care Nurses' Perception of the Complementary & Alternative Therapy (가정전문간호사의 대체요법에 대한 인식)

  • Jang, Kyoung-Ja;Kim, Hyun-Li
    • Journal of Korean Academic Society of Home Health Care Nursing
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    • v.13 no.1
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    • pp.24-32
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    • 2006
  • The purpose of this study is to predict the degree of taking the complementary & alternative therapy in the home care nursing service and provide basic data for the application of it. To accomplish this, degree of general recognition of the complementary & alternative therapy, experiences, degree of concern, applicability of the therapy, and educational need should be studied. This study is a descriptive research survey on the home care nurses working at 73 medical centers out of 125 nationwide who provide hospital based home nursing care. The data was collected from Sep. 20, to Oct. 20, 2004 by ChoiHeyran's questionaries (2002). The data was analyzed by the frequency and the percentage. The results of this study are as follows ; 1. The degree of pre-cognition on the complementary & alternative therapy is very high. Information about the therapy was mostly obtained through medias. Home care nurses understand that he desirable treatment is to practice medical treatment and complementary & alternative therapy simultaneously. While 50% of them have already practiced complementary & alternative therapy among their patients. The most commonly used therapy is Acupressure. And Home care nurses have open and positive attitudes about the complementary & alternative therapy as to answer they aye ready to recommend it to their patients. 2. Over half of the Home care nurses met patients taking complementary & alternative therapy. 94.5% of them think scientific diagnosis on the effect of the therapy. advice from the doctor. and the special working staff is required to apply it on to the home care nursing. 3. 68.5% of the Home care nurses have taken education on the therapy through general comprehensive instructions and supplementary. Most of them want to have a opportunity education on the therapy because they want to provide comprehensive nursing and diversified nursing service. The preferred educations are Hand acupuncture, Acupressure & Massage and Aromatherapy, in that order. Based on the above results, the followings are recommended. 1. A study that stipulates the types, applications, and efficiency assessment of the complementary & alternative therapy practiced by Home care nurses in the home care nursing care procedure. And systematic and scientific nursing intervention be developed.

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