• Journal of IKEEE
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• v.23 no.3
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• pp.858-864
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• 2019

A clock system is proposed to eliminate data loss due to frequency difference between sensor nodes in a sensor utility network. The proposed clock system for each sensor node consists of a bust clock-data recovery (CDR) circuit, a digital phase-locked loop outputting a 32-phase clock, and a digital frequency synthesizer using a programmable open-loop fractional divider. A CMOS oscillator using an active inductor is used instead of a burst CDR circuit for the first sensor node. The proposed clock system is designed by using a 65 nm CMOS process with a 1.2 V supply voltage. When the frequency error between the sensor nodes is 1%, the proposed burst CDR has a time jitter of only 4.95 ns with a frequency multiplied by 64 for a data rate of 5 Mbps as the reference clock. Furthermore, the frequency change of the designed digital frequency synthesizer is performed within one period of the output clock in the frequency range of 100 kHz to 320 MHz.

• Korean Journal of Psychosomatic Medicine
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• v.24 no.1
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• pp.94-101
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• 2016

Objectives : Anemia is a common problem in the management of elderly patients. Recent studies reported that anemia was associated with cognitive impairment and Alzheimer's disease. This study was aimed to analyze the differences of hemoglobin levels in Korean patients with Alzheimer's disease(AD) dementia, mild cognitive impairment(MCI), and healthy controls. Furthermore, the study also examined if any association between hemoglobin levels and cognitive functions existed. Methods : A total of 116 Korean elderly adults were participated in this study(mean age 74.67 years ; 60.3% female). The Korean version of the Mini-Mental State Examination(MMSE-K), Clinical Dementia Rating(CDR) and Global Deterioration Scale(GDS) were applied to all subjects. Hematological and related blood chemistry values were investigated. Results : We found that patients with AD dementia had significantly lower hemoglobin and hematocrit levels than MCI subjects and healthy control group. The hemoglobin levels showed a positive correlation with MMSE-K and negative correlation with CDR, GDS. Conclusions : Among Korean elderly, low hemoglobin level is associated with a cognitive impairment. This study indicates that AD is associated with anemia, and low hemoglobin levels may contribute to potentially useful clinical markers of AD. The risk factor for dementia needs to be confirmed by prospective longitudinal studies in a larger group of patients.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3A
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• pp.290-296
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• 2007

We propose new routing scheme, Cooperative Diversity-based Routing (CDR) which utilizes the cooperative space diversity for power saving and performance enhancement of wireless ad-hoc networks. The improved performance is compared with Multi-hop Relay Routing (NRR) by analytical methods. When the required outage probability is $1\times10^{-3}$ at the destination node in ad-hoc networks with 7 nodes, we noticed that each node can save power consumption by 15.5 dB in average, by using our proposed CDR compared to MRR.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.3
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• pp.185-192
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• 2013

In this paper, a clock and data recovery (CDR) circuit that supports triple data rates of 1.62, 2.7, and 5.4 Gbps for DisplayPort 1.2 standard is described. The proposed CDR circuit covers three different operating frequencies with a single VCO switching the operating frequency by the 3-bit digital code. The prototype chip has been designed and verified using a 65 nm CMOS technology. The recovered-clock jitter with the data rates of 1.62/2.7/5.4 Gbps at $2^{31}$-1 PRBS is measured to 7/5.6/4.7 $ps_{rms}$, respectively, while consuming 11 mW from a 1.2 V supply.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.2
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• pp.155-167
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• 2015

An adaptive equalization scheme based on all-digital jitter measurement is proposed for a continuous time linear equalizer (CTLE) preceding a clock and data recovery (CDR) in a receiver circuit for high-speed serial interface. The optimum equalization coefficient of CTLE is determined during the initial training period based on the measured jitter. The proposed circuit finds automatically the optimum equalization coefficient for CTLE with 20", 30", 40" FR4 channel at the data rate of 5 Gbps. The chip area of the equalizer including the adaptive controller is 0.14 mm2 in a $0.13{\mu}m$ process. The equalizer consumes 12 mW at 1.2 V supply during the normal operation. The adaptive equalizer has been applied to a USB3.0 receiver.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.2
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• pp.267-272
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• 2017

In this paper, we suggested that a RF-front module of down-converter that represents the lowest noise figure to receive high quality video signals because the attenuation occurs in the atmosphere over 20GHz. By budget analysis of CDR, SFDR and CIP3 of RF-FEM, we also analyzed the parameters and linearity that presents high dynamic range. The total gain of designed Ka-band down-converter is 61.8dBand noise figure is 1.05dB, so gain and noise figures show excellent properties. In the future, the designed RF-FEM will be applied to the Ka-band satellite down-converter for UHD-class video transmission.

• Child Health Nursing Research
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• v.12 no.3
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• pp.333-340
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• 2006

Purpose: This study was to restandardize the Child Development Review (CDR) which was developed by Dr. Ireton and based on Child Development Inventory (CDI). Method: The participants were 1143 children who were aged 12months to 6.3years old and parents. They were the sample for standardization study of CDI. The age level assigned to each item of Korean version of CDI were assessed. The reliability and validity was analyzed by reliability coefficient and concurrent validity analysis. Result: The item set was revised by the age level of each item at which at least 75 percent of parents answered YES to the statement. The child development chart was composed of 100 item which include social, self-help, gross motor, fine motor, and language sector. The internal consistency coefficient of the instrument was .93. The concurrent validity with Korean Denver II was good. Conclusions: The Korean version of CDR showed good reliability and validity. It could be utilized for developmental screening at pediatric clinic and child care center.

• Journal of Korea Water Resources Association
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• v.55 no.6
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• pp.447-459
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• 2022

This study estimated the grid-type precipitation quantile for the Korean Peninsula using PERSIANN-CCS-CDR (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Cloud Classification System-Climate Data Record), a satellite based re-analysis precipitation data. The period considered is a total of 38 years from 1983 to 2020. The spatial resolution of the data is 0.04° and the temporal resolution is 3 hours. For the probability distribution, the Gumbel distribution which is generally used for frequency analysis was used, and the probability weighted moment method was applied to estimate parameters. The duration ranged from 3 hours to 144 hours, and the return period from 2 years to 500 years was considered. The results were compared and reviewed with the estimated precipitation quantile using precipitation data from the Automated Synoptic Observing System (ASOS) weather station. As a result, the parameter estimates of the Gumbel distribution from the PERSIANN-CCS-CDR showed a similar pattern to the results of the ASOS as the duration increased, and the estimates of precipitation quantiles showed a rather large difference when the duration was short. However, when the duration was 18 h or longer, the difference decreased to less than about 20%. In addition, the difference between results of the South and North Korea was examined, it was confirmed that the location parameters among parameters of the Gumbel distribution was markedly different. As the duration increased, the precipitation quantile in North Korea was relatively smaller than those in South Korea, and it was 84% of that of South Korea for a duration of 3 h, and 70-75% of that of South Korea for a duration of 144 h.

• Journal of Preventive Medicine and Public Health
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• v.39 no.3
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• pp.243-248
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• 2006

Objectives: The Quality of Life-Alzheimer's Disease (QOL-AD) scale is a reliable and valid tool for assessing the quality of life (QOL) in the elderly with dementia. This study aimed to develop the Korean version of Quality of Life-Alzheimer's Disease (KQOL-AD) scale for the demented elderly living in the community. Methods: KQOL-AD was administered to two groups: 24 demented elderly and 72 cognitively impaired elderly with no dementia (CIND) who were living in the community Each elderly person and their caregiver rated the elderly QOL. The Korean version of mini-mental state examination (MMSE-K), the clinical dementia rating (CDR), the activities of daily living (ADL), and the neuropsychiatric inventory (NPI) were also assessed. The reliability and validity of the KQOL-AD were examined. Results: In the dementia group, the internal consistency (Cronbach's $\alpha$), the split half and the test-retest reliabilities of the KQOL-AD were excellent. Scores on the KQOL-AD were significantly correlated with the scores of the NPI, but they were not significantly correlated with scores of the MMSE-K, CDR and ADL. In addition, the CIND group showed similar results to the dementia group. Conclusions: KQOL-AD might be a reliable and valid instrument for assessing QOL in the elderly with dementia It could be used as an important outcome measure for research on the demented elderly.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.221-228
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• 2003

The stress corrosion index of Kumamoto andesite are evaluated by two types of testing method. One is the uniaxial compression test under various water vapor pressures, and the other is the double torsion (DT) test under a constant water vapor pressure. For the uniaxial compression tests, the uniaxial compressive strength increases linearly with decreasing water vapor pressure on the double logarithmic coordinates. As the results, the stress corrosion index obtained is estimated 44. On the other hand, in the DT test, the relaxation (RLX) test and the constant displacement rate (CDR) test were conducted. For the CDR test, as the displacement rate of loading point increases, the crack velocity increases. However, the fracture toughness is constant regardless of the change in displacement rate and the average fracture toughness is evaluated $2.07MN/m^{3/2}$. For the RLX test, the crack velocity-stress intensity factor curves are smooth and linear. The stress corrosion index estimated from the curves is 37. Comparing stress corrosion indexes in the uniaxial compression test and the DT test, there is no significant difference in these values, and they are considered to be in coincident each other regardless of testing methods. Therefore, it is concluded that stress corrosion is one of material constants of rock.