• 제목/요약/키워드: IQ

검색결과 382건 처리시간 0.033초

위상 잡음과 직교 불균형이 있는 OFDM 수신 신호의 보상 (Compensation of OFDM Signal Degraded by Phase Noise and IQ Imbalance)

  • 유상범;김상균;유흥균
    • 한국전자파학회논문지
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    • 제19권9호
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    • pp.1028-1036
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    • 2008
  • OFDM(Orthogonal Frequency Division Multiplexing) 시스템에서 직교 불균형 문제는 송수신기의 front-end에서 발생하며, 성상도에 영향을 주게 되어 BER(Bit Error Rate)을 증가시킨다. 또한, 위상 잡음은 송수신시 국부 발진기에서 발생되는 잡음으로 각 부반송파의 직교성을 깨뜨림으로써 시스템 성능을 크게 저하시킨다. 기존 방식인 PNS(Phase Noise Suppression) 알고리즘은 이러한 위상 잡음을 효과적으로 제거하는 방법이지만 직교 불균형 이동시에 적용되면 오히려 성능이 감소된다. 본 논문에서는 OFDM 시스템의 수신기에서 하향 변환 시 발생하는 직교 불균형과 위상 잡음의 영향을 분석하고, 수신기 FFT(Fast Fourier Transform) 후단에서 파일럿 심볼을 사용하여 CPE를 먼저 제거하고 직교 불균형과 위상 잡음의 성분을 검출하여 등화기의 판정 기준으로 사용하여 보상하는 방법을 제시하였다. 또, 다른 기존 방식들은 FFT 후단에서 추정하고 피드백 시키거나 프리엠블과 같은 시퀀스를 사용하는 방식이지만, 본 논문에서는 FFT 후단에서 MMSE 등화기만을 사용하여 제거하므로 기존의 방법보다 복잡도가 줄어든다. 기존의 위상 잡음 제거 방식에 ICI(Inter Carrier Interference) 제거 기능을 추가하고 직교 불균형 성분을 추출하여 MMSE(Minimum Mean Square Error) 과정 중에 적응 forgetting factor를 적용하면 성능 개선과 직교 불균형 성분의 영향이 줄어들며 성능이 개선됨을 보인다.

초등학생의 Dental IQ 수준과 구강보건 관리실태 (Dental IQ and Oral Health Care Status of Elementary School Students)

  • 김광덕;전진호
    • 보건교육건강증진학회지
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    • 제20권2호
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    • pp.95-112
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    • 2003
  • Objectives: Oral health care program for the elementary school children (ESOHCP) should be met the first priority because dental caries are highly sensitive and prevalent among them. This study was performed to enhance the efficiency of ESOHCP, and their oral health promotion. Methods: The Subjects were 346 students (3rd grade 163, 6th grade 185) of one elementary school in Busan. Dental IQ and actual oral health status; the decayed, mixing and filling teeth were checked through questionnaire and oral health examination from April to June 2002. Dental IQ was presented out of one hundred, and data analysis was done using SAS (ver 8.1) program. Results: The students' cognitive level about the causative and preventive factor of dental caries was relatively high. However, the practical aspects of preventive behavior - tooth brushing; three times per day (20%), three minutes per time (22%), oral health examination; one time per three months (10%) left much to be desired. And, only 27% of the subjects had experienced in school oral health education. The mean level of dental IQ was 79 out of 100, and 51 % and 42% of them had the decayed and teeth with filling, respectively, with the rate of DMFT 82%, DT 43%, FT 57%. The level of dental IQ was higher in case of having his (her) own tooth brush (p=0.072), standard tooth brushing (p<0.001) three times per day, post meal, three minutes per time, present experience of oral health examination (p<0.001) and dental clinic visit (p<0.001). The grade of caries was more serious in case of 6th grade (p=0.059), an absence of his (her) own tooth brush (p= 0.090), present experience of oral health examination (p=0.021), and an absence of regular dental clinic visit (p=0.003). The frequency of oral health examination (γ= 0.620), tooth brushing; times per day (γ=0.445), post meal (γ=0.355), expending times per brushing (γ=0.352), right cognition to the treatment of caries (γ=0.401), positive attitude to dental treatment (γ=0.387), the frequency of dental clinic visit for the past one year (γ=0.152) showed significant correlation with dental IQ. In the multivariate analysis, dental IQ was influenced by the frequency of oral health examination, right cognition to the cause of caries, times of teeth brushing per day, right cognition to the treatment of caries, etc., with adjusted R2=0.857. Conclusion: Though the students' cognitive level about the causative and preventive factor of dental caries was high, the practical aspects of preventive behavior left much to be desired. Ant the current ESOHCP considered to be still inefficient. However, frequent dental visits had apparent correlation with hish level of dental IQ. The specialized and practical program should be needed for the efficient ESOHCP. Harmonized effort from educational, health and dental society is essential.

IQ Imbalance와 위상 잡음을 고려한 OFDM 통신 시스템의 성능 분석 (Performance Analysis of OFDM Communication System with the IQ Imbalance and Phase Noise)

  • 김상균;유흥균;강병수;이광천
    • 한국전자파학회논문지
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    • 제18권7호
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    • pp.757-765
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    • 2007
  • OFDM(Orthogonal Frequency Division Multiplexing) 시스템은 이동성이 있는 고속 데이터 전송에 적합한 전송 방법으로 널리 알려져 있지만, 위상 잡음과 직교 불균형(IQ imbalance)에 매우 민감한 특성을 보이는 단점이 있다. 그러므로, 본 논문에서는 위상 잡음 특성에 따른 위상 잡음 분산을 계산한 다음, 직교 불균형이 있는 OFDM 시스템의 통신 성능을 분석하였다. 시뮬레이션 결과, 위상 잡음의 분산과 직교 불균형의 크기 변화에 따라 통신 성능이 변화하는 것을 분석하였다. 분석 결과, 진폭 불균형이 ${\varepsilon}$=0.2; 0.3; 0.4이고, 위상 불균형이 ${\phi}=10^0$이고, 위상 잡음의 분산 ${\sigma}^2=0.012$일 때, BER은 $10^{-5}$에서 각각 2.88 dB, 3.61 dB, 4.69 dB의 SNR penalty가 존재한다.

청소년의 지능범주별 대뇌피질 변화성 분석 연구 (Analysis on the Variability of Cerebral Cortex per Intellectual Category in Adolescents)

  • 김예림
    • 영재교육연구
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    • 제23권3호
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    • pp.421-434
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    • 2013
  • 청소년들의 뇌는 급속한 변화를 겪는다. 그동안 신경해부학적 특성과 일반지능(IQ)과의 관련성을 알아보기 위한 연구가 지속적으로 이뤄져 왔으나 대부분 단편적이었다. 본 연구는 단순히 대뇌 피질 두께를 한 번 측정한 것이 아니고, 대뇌 피질 두께의 변화를 추적하여 일반지능과 그 변화 간의 관련성을 추정하였다. 건강한 청소년 75명(M=16세 4개월)을 5단계의 지능범주별로 나눈 뒤 6개월의 간격을 두고 MRI 촬영을 두 번씩 하여 대뇌 피질 두께 변화를 알아냈다. 그 결과 일반지능 범주별로 대뇌 피질 두께 변화에 차이가 크게 나타났다. 일반지능이 120 이상인 세 그룹은 관찰 대상인 11개 뇌 영역의 대뇌 피질 두께가 모두 감소했으나, 그 이하의 두 개 그룹에서는 지능이 낮을수록 늘어나는 영역이 5~8개나 됐다. 이는 일반지능이 낮을수록 대뇌피질의 성숙이 늦어지는 것으로 추정할 수 있다.

불면환자의 수면의 질 척도, 우울척도, 한방진단시스템과의 연관성 연구(1) (Study on the Association of PSQI, IQ, BDI and DSOM in the Insomnia Patients(l))

  • 오경민;김보경
    • 동의신경정신과학회지
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    • 제20권3호
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    • pp.89-119
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    • 2009
  • Objectives : This study was to investigate the association of Pittsburgh Sleep Quality Index(PSQI), Insomnia Questionaire(IQ), Beck Depression Inventory(BDI) and Diagnos system of oriental medicine(DSOM) in the Insomnia Patients. Methods : For this study, we carried out PSQI, IQ, BDI and DSOM of 37 patients with insomnia who have come to Donguei oriental hospital of Donguei university from November 2008 to May 2009. And Using cross tabulation analysis, verified the association of PSQI, IQ, BDI and DSOM. Results : 1. The most Frequent Pathogenic Factor is blood-deficiency(血虛) in total patients. 2. The score of BDI has positive correlation with sc10 of deficiency of qi(氣虛), damp(濕), kdney(腎) in total patients. 3. The score of PSQI has positive correlation with zp of liver(肝) in total patients. 4. The score of PSQI has positive correlation with sc10 and zp of insufficiency of Yin(陰虛), and the score of BDI has positive correlation with sc10 of blood stasis(血瘀) and zp of liver(肝) in female patients. 5. The score of PSQI has positive correlation with sc10 of deficiency of qi(氣虛) and zp of heart(心), and the score of IQ has positive correlation with sc10 of liver(肝) in male patients. 6. The duration from onset in the group of 22-59years are longer than the group of 60-80 years and the duration of using hypnotics have positive correlation with total sleep time in 22-59years group. 7. The score of PSQI has positive correlation with zp of liver(肝) in 22-59years group. 8. The score of PSQI has positive correlation with the score of BDI in 60-80years group. 9. The score of BDI has positive correlation with sc10 of deficiency of qi(氣虛) and zp of blood-deficiency(血虛), and the score of IQ has positive correlation with zp of coldness(寒) in 60-80years group. 10. The score of IQ has positive correlation with sc10 and zp of dryness(燥) in below 6 Months Group. 11. The score of PSQI has positive correlation with the score of BDI in over 6 Months Group. 12. The score of PSQI has positive correlation with zp of liver(肝) in over 6 Months Group. 13. The score of IQ has positive correlation with sc10 of dryness(燥) in BDI 2nd Grade Group. 14. The score of BDI has positive correlation with sc10 of kidney(腎) and the age has positive correlation with zp of heart(心) in BDI 3rd Grade Group. 15. The age has positive correlation with sc10 of damp(濕) in BDI 4th Grade Group. Conclusions : This study provides insights into the complicated associations of the pattern of insomnia with depression and Diagnos system of oriental medicine. And especially this study showed apparent correlation between insomnia and depression in 60-80years group and over 6 months group.

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A Correlative Approach for Identifying Complex Phases by Electron Backscatter Diffraction and Transmission Electron Microscopy

  • Na, Seon-Hyeong;Seol, Jae-Bok;Jafari, Majid;Park, Chan-Gyung
    • Applied Microscopy
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    • 제47권1호
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    • pp.43-49
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    • 2017
  • A new method was introduced to distinguish the ferrite, bainite and martensite in transformation induced plasticity (TRIP) steel by using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). EBSD is a very powerful microstructure analysis technique at the length scales ranging from tens of nanometers to millimeters. However, iron BCC phases such as ferrite, bainite and martensite cannot be easily distinguished by EBSD due to their similar surface morphology and crystallographic structure. Among the various EBSD-based methodology, image quality (IQ) values, which present the perfection of a crystal lattice, was used to distinguish the iron BCC phases. IQ values are very useful tools to discern the iron BCC phases because of their different density of crystal defect and lattice distortion. However, there are still remaining problems that make the separation of bainite and martensite difficult. For instance, these phases have very similar IQ values in many cases, especially in deformed region; therefore, even though the IQ value was used, it has been difficult to distinguish the bainite and martensite. For more precise separation of bainite and martensite, IQ threshold values were determined by a correlative TEM analysis. By determining the threshold values, iron BCC phases were successfully separated.

저소득층 장애모 가정 유아의 인지 및 사회적 적응능력의 발달 (Development of Cognitive and Social Adaptive Ability in Preschool Children of Low income, Disabled Mothers)

  • 윤혜경;장유경;박선희;박윤조;박혜원
    • 아동학회지
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    • 제30권1호
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    • pp.27-41
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    • 2009
  • This study examined the cognitive and social development of children of low income, disabled mothers. Sixty-four disabled mothers and their 3- to 5-year-old normally developing children participated. Children's IQ, receptive vocabulary, and social adaptive ability were measured with Korean-Wechsler Preschool and Primary Scale of Intelligence (Park et al.,1996), Peabody Picture Vocabulary Test-Revised (Seoul Community Rehabilitation Center, 1995), and Social Maturity Test(Kim & Kim, 1995), respectively. Results showed that IQ and receptive vocabulary scores were lower than average and that verbal IQ was positively related to shared reading time and library use; verbal IQ was negatively related to duration of child-care attendance. Children's social quotient was higher than average and positively related to mother's employment status and amount of books in the home.

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The Role of Intelligence (IQ) on The Globalization-Income Inequality Nexus: A Threshold Regression Approach

  • IBRAHIM, Saifuzzaman;MAZLINA, A.R.;AZMAN-SAINI, W.N.W.;BURHAN, Nik Ahmad Sufian
    • The Journal of Asian Finance, Economics and Business
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    • 제8권12호
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    • pp.9-17
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    • 2021
  • Globalization is an economic process responsible for the increase of interdependence of world economies. It enhances the mobility of national resources internationally via the integration of markets, trade and investments with minimal barriers to slow the flow of products and services. Although globalization has some positive impacts on the economy, it is said to be a factor in the decline of income inequality of the participating countries. However, the results of previous studies on the relationship between globalization and income inequality are inconclusive. This suggests that there are other factors influencing the relationship between the two variables. The purpose of this study is to examine the role of intelligence (IQ) in the globalization-income inequality relationship. This study employs the threshold regression technique and cross-nation observations from 117 sample nations for the period 1980-2016. The results show that the impact of globalization on income inequality in a nation relies on its IQ level. The results imply that economic globalization has a negative impact on income inequality in nations with lower IQ levels. It widens the gap between the poor and rich. While in nations with higher IQ levels, it seems to not have any significant impact on income distribution.

영아기 가정의 책읽기 경험과 지능발달 : 종단연구 (Picture Book Reading Practices with Very Young Children and their Intellectual Development : A Longitudinal Study)

  • 장유경;최유리
    • 아동학회지
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    • 제30권4호
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    • pp.47-56
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    • 2009
  • This longitudinal study examined picture book reading practices with very young children and its influence on early intellectual development. The home picture book reading activities of 322 infants and their mothers were assessed by questionnaire every 6 months from 18 months till 42 months of age. Infants' IQ was measured with Korean-Wechsler Preschool and Primary Scale of Intelligence(Park et al., 1996) at 42 months. Results showed that monthly book expense (r=.28, p<.01) and infants' asking for reading (r=.14, p<.05) at 18 months were positively correlated with IQ at 42 months. Reading time between 24 and 42 months correlated positively with IQ(r=.17~.34, p<.01). These results reveal the importance of early book environment and actual reading time in the intellectual development of very young children.

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IQ 변조기법을 이용한 모터제어 (USING IQ MODULATION MOTOR CONTROL)

  • 류나이;안영주;이형기
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2008년도 제39회 하계학술대회
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    • pp.1671-1672
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    • 2008
  • 전동기는 일반적으로 우리 일상에서 가장 많이 쓰이는 동력장치 중 하나이다. 이런 전동기를 제어함에 있어서 주기적 외란은 전체 시스템의 안정성에 큰 영향을 미친다. 특히, 정밀제어시스템에서는 반드시 고려되어야 할 요소이다. 본 논문에서는 신호처리기법의 일종인 IQ 변조 알고리즘을 이용한 제어기를 제안한다. 제안하는 제어알고리즘은 외란을 고려하지 않은 시스템모델에 대하여 설계되어진 제어기와 IQ 변조기법을 이용하여 외란을 추정하여 설계되어지는 제어기로 이루어진다. 이 제어 알고리즘은 전동기에서 발생하는 주기적 외란에 의한 오차를 현저하게 줄인다. 본 논문을 통해 제안하는 제어알고리즘의 우수성과 타당성을 검증한다.

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