• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.4
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• pp.148-153
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• 2003

In this paper, the low voltage 3V Sigma-Delta Digital Analog Converter(DAC) is designed for using in the transmitter of ADSL analog front-end. We have developed the CMOS DAC according to ANSI T1.413-2(DMT) standard specifications of the chip. The designed 4th-order DAC is composed of three block which are 1-bit DAC, 1st-order Switched-Capacitor filter and analog active 2nd-order Resistor-Capacitor(RC) filter. The HSPICE simulation of the designed DAC showing 65db SNR, is connected with 1.1MHz continuous lowpass filter. And also, we have performed the circuits verification and layout verification(ERC, DRC, LVS) followed by fabrication using TSMC 2-poly 5-metal p-substrate CMOS $0.35{\mu}m$ processing parameter. Finally, the chip testing has been performed and presented in the results.

• Journal of Satellite, Information and Communications
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• v.4 no.2
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• pp.1-4
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• 2009

This paper introduces not only what the ST-IT convergent technology is, but also the present technological status of ST and IT in order that the ST-IT convergent technology may not be a simple topic of conversation but a key word of our country's new growth engine. This paper also describes a development direction for the technology convergence as some dynamic changes can be anticipated to create the new value and market because the wall between technologies and industries may be broken down due to the development of STIT convergent technology in the future.

• East Asian mathematical journal
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• v.35 no.4
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• pp.467-488
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• 2019

The purpose of this study is to analyze multiplication facts(1st and 0th multiplication) in elementary mathematics. In the 2015 revised curriculum, students learn multiplication and multiplication facts in the 2nd grade. Many teachers experience difficulties in organizing the multiplication problem situation in multiplication facts(1st and 0th multiplication). This study aims to consider the causes of these difficulties and devise teaching methods. The method of this study is a comparative and analytic method. In order to compare textbooks, we select the Korean elementary mathematics textbooks(1st curriculum~2015 revised curriculum) and the six foreign elementary mathematics textbooks(Taiwan, Japan, Finland, Unites States, Hongkong, Singapore). As a result, the multiplication problem situation and the multiplication model assume the same bundle and bundle model. Also, we must consider the teaching timing of multiplication facts(1st and 0th multiplication) and the use of commutative law. In this study, we proposed a multiplication teaching scheme in consideration of the multiplication problem situation and teaching model, teaching period and commutative law etc.. to teach multiplication facts(1st and 0th multiplication) in elementary mathematics.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.13 no.1
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• pp.107-115
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• 1983

This study was performed in order to analyse the morphology of maxillary sinus on orthopantomogram. The author anlaysed the anterior-posterior width of mesial wall, the extension of anterior margin in maxillary sinus and the interrelation between the root apex of maxillary 1st molar and sinus floor. The films consisted of 514 orthopantomograms divided into three groups ranging the 3rd decade, 4th and 5th decade and 6th decade. The obtained results were as follows: 1. The mean dimensions of the anterior - posterior width of mesial wall were 43.81±4.55㎜ for male and 43.80±4.49㎜for female in the right of maxillary sinus, 43.75±74㎜ for male and 43.37±3.92㎜ for female. 2. With age, the dimensional change of the anterior - posterior width of mesial wall in maxillary sinus was not observed. 3. The extension order of anterior margin of the maxillary sinus was distal to canine side, 1st premolar mesial side, canine mesial side, and 1st premolar distal side. 4. In the distance between the root apex of upper 1st molar and the maxillary sinus floor, the degree of closeness was more increased in the older-aged group than in the younger-aged group.

• Progress in Superconductivity
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• v.9 no.1
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• pp.45-49
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• 2007

We have investigated the optimum combination of the environmental noise condition and type of SQUID pickup coil in order to obtain maximum signal-to-noise ratio (SNR). The measurement probe consists of 1st order gradiometer with pickup coils of 100 mm, 70 mm, and 50 mm baseline length, a 2nd order gradiometer with 50 mm baseline, and a magnetometer. The pickup coils are fabricated by winding Nb wire on a bobbin with 200 mm diameter. Noise and heart signal of a healthy male were measured by various SQUID sensors with different types of pickup coils in various magnetically shielded rooms (MSR), and compared to each other. The shielding factors were found to be 43 dB, 35 dB and 25 dB at 0.1 Hz for MSR-AS, MSR-BS, MSR-CS, respectively. White noises were $3.5\;fT/Hz^{1/2}$, $4.5\;fT/Hz^{1/2}$ and $3\;fT/Hz^{1/2}$ for the 1st order gradiometers, the 2nd order gradiometers, and magnetometer for all MSRs. SNR of the magnetometer was up to 56 dB in MSR-AS, while the 1st order axial gradiometer with 70 mm baseline length was up to 54 dB in MSR-BS. The 2nd order axial gradiometer with 50 mm baseline length of pickup coil was found to be up to 40 dB in MSR-CS.

• Journal of Ecology and Environment
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• v.35 no.1
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• pp.27-34
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• 2012

Typha angustifolia has ecological characteristics of clonal growth similar to Phragmites australis. The plant spreads byclonal growth and seed dispersal. In this study, for the three stands which have different settlement age at the Baksilji wetland in Korea, genetic diversity was estimated by random amplification of polymorphic DNA analysis to evaluate the change in genetic diversity of T. angustifolia during stand development in the same population. Stand (ST) 1 was the oldest and ST 4 was the youngest. ST 5 was in a small ditch out of the Baksilji. Although the ST 1, ST 2, and ST 3 did not differ significantly in vegetational or physical environment, the genetic diversity estimated according to Nei's gene diversity (h) and the Shannon index (i) increased in the order of ST 1 < ST 2 < ST 3 contrary to formative age. The genetic diversity of ST 4 was much higher than that of the other three stands. ST 4 has similar abiotic environmental conditions with slight T. angustifolia dominance, and seems to be in the early establishment stage. ST 5 differed from the other stands in vegetational and soil environments, which can result in stressful cattail conditions. Even though the ST 5 stand was not younger than the ST 4 stand, ST 5 showed the highest genetic diversity. Our results indicate that after early settlement of the T. angustifolia population, genetic diversity within the species decreased over time and that the decreasing pattern of genetic diversity within T. angustifolia stands is not likely to occur under stressful conditions.

• Journal of the Korea Fashion and Costume Design Association
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• v.18 no.1
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• pp.121-133
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• 2016

The purpose of this study is to recognize the differences of visual evaluation by variations in pattern and silhouette of the block dresses. The stimuli are 9 samples: 3 variations of the silhouette and 3 variations of the size of pattern. The data has been obtained from 55 fashion students and has been analyzed by using Factor Analysis, Anova, Scheffe's Test and the MCA method. The results of this study are as follows; 1) The visual evaluation by pattern and silhouette of block dresses are composed of 4 factors: lovable personality, physical characteristics, boldness, and simplicity. 2) Block dresses were evaluated to display the figure more efficiently, such as looking slimmer or taller, in the order of 2nd stage, 1st stage, and 3rd stage in every silhouette. As the patterns became bigger, straight silhouette dresses were judged to have bolder, more dignified images. 3) Block dresses were evaluated to have cute and lively images in order of hourglass silhouette, straight silhouette, and fitted silhouette in every pattern. They were evaluated to appear slimmer and taller in order of hourglass silhouette, fitted silhouette, and straight silhouette in every pattern. 1st stage and 2nd stage dresses were evaluated to have a bolder, more dignified image in order of fitted silhouette, hourglass silhouette, and straight silhouette. 4) The pattern and the silhouette of the block dresses interacted with boldness. These were the boldest, most dignified image in the fitted silhouette and 1st stage, while they were not judged so in the case of the straight silhouette and 1st stage. 5) According to the MCA regarding lovable personality and physical characteristics, the silhouette affected the visual image of the block dresses more than the pattern did. According to the MCA on simplicity, the pattern affected the visual image of the block dresses more than the silhouette.

• Journal of Hospice and Palliative Care
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• v.7 no.2
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• pp.232-237
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• 2004

Purpose: DNR order is generally accepted for cancer patients near the end of life at Hospice Ward. It means not only no CPR when cardiopulmonary arrest develops but no aggressive meaningless medical interventions. Usually on admission, we discuss with the patients' family about DNR order at the Hospice Ward. Recently, we experienced a terminal lung cancer patient who had been on the ventilator for two months after pulmonary arrest. CPR and artificial ventilation were performed because patient's family refused DNR order. There is no consensus when, who, and how DNR order could be written for terminal cancer patients in Korea, yet. Methods: Hospice charts of 60 patients who admitted between Jan and Jun 2003 to Hospice Ward were reviewed retrospectively. Results: The median age was 66(range $31{\sim}93$) and there were 31 males and 29 females. Their underlying cancers were lung (12), stomach (12), biliary tract (7), colon (6), pancreas (4) and others (19). The persons who signed DNR order were son (22), spouse(19), daughter (16) and others (3). But, there was no patients who signed DNR order by oneself. Thirty families of 60 patients signed on day of admission and 30 signed during hospitalization when there were symptom aggravation (19), vital sign change (4), organ failure (3) and others (4). There were 13 patients who died within 5 days after DNR order. Most of patients died at our hospice ward, except in 1 patient. The level of care was mostly 1, except in 2 patients. (We set level of care as 3 categories. Level 1 is general medical care: 2 is general nursing care: 3 is terminal care.) Conclusion: We have to consider carefully discussing DNR order with terminal cancer patients in the future & values on withholding futile intervention.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.880_881
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• 2009

This paper improves the calculating method about the inductance with the high order frequency coreloss. It is different in which the analyzed inductance for calculating IPMSM and the measured thing for experiment. Due to this phenomenon, the expected input voltage differs from the inquired input voltage for operating the motor. This results from the coreloss margin which have both the 1st order and high order frequency value. For reducing the inductance error, after calculating the equivalence coreloss resistance with having the 1st order frequency Back_EMF and coreloss, designing the inductance with the high order frequency which occurred by the coreloss of high order frequency, and comparing the renovated inductance analysis value with the measured thing.

• Journal of Communications and Networks
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• v.6 no.1
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• pp.1-8
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• 2004

In this paper, we investigate the properties and performance of space-time bit-interleaved coded modulation (STBICM) systems in fast Rayleigh fading channels. We first show that ST-BICM with QPSK signaling in fast fading channels possesses the uniform distance property, which makes performance analysis tractable. We also derive the probability distribution of the squared Euclidean distance between space-time symbols assuming uniform bit-interleaving. Based on the distribution, we show that the diversity order for each codeword pair becomes maximized as the frame length becomes sufficiently long. This maximum diversity order property implies that the bit-interleaver transforms an ST-BICM system over transmit diversity channels into an equivalent coded BPSK system over independent fading channels. We analyze the performance of ST-BICM in fast fading channels by deriving an FER upper bound. The derived bound turns out very accurate, requiring only the distance spectrum of the binary channel codes of ST-BICM. Numerical results demonstrate that the bound is tight enough to render an accurate estimate of performance of ST-BICM systems.