• Journal of Korean Society for Quality Management
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• v.51 no.4
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• pp.551-571
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• 2023

Purpose: The purpose of this study is to propose useful suggestions by analyzing the causal effect relationship between the failure rate of quality and the process variables in the C5ISR domain of the defense industry. Methods: The collected data through the in house Systems were analyzed using Big data analysis. Data analysis between quality data and A/S history data was conducted using the CRISP-DM(Cross-Industry Standard Process for Data Mining) analysis process. Results: The results of this study are as follows: After evaluating the performance of candidate models for the influence of inspection data and A/S history data, logistic regression was selected as the final model because it performed relatively well compared to the decision tree with an accuracy of 82%/67% and an AUC of 0.66/0.57. Based on this model, we estimated the coefficients using 'R', a data analysis tool, and found that a specific variable(continuous maximum discharge current time) had a statistically significant effect on the A/S quality failure rate and it was analysed that 82% of the failure rate could be predicted. Conclusion: As the first case of applying big data analysis to quality issues in the defense industry, this study confirms that it is possible to improve the market failure rates of defense products by focusing on the measured values of the main causes of failures derived through the big data analysis process, and identifies improvements, such as the number of data samples and data collection limitations, to be addressed in subsequent studies for a more reliable analysis model.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.31 no.4
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• pp.214-224
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• 2020

Objectives: This study aimed to examine the trend in diagnostic prevalence of psychiatric disorders in children and adolescents. Methods: Individuals aged 0-18 years were included in the study based on the National Health Insurance Claims Data. To investigate the trends in diagnosis and diagnostic prevalence of psychiatric disorders reflecting the decrease in the birth rate, data were analyzed from 2010 as a reference year to 2015. Results: The number of patients diagnosed with psychiatric disorder decreased annually, from 23,412 on 2010 to 18,821 on 2015. The most common disorder was hyperkinetic disorder in male and depressive episode in female. Although there was no significant change in overall diagnostic prevalence rate of psychiatric disorders, age groups <10 years and some disorders had significant changes in prevalence rate. This study classified the diagnostic prevalence by age into two unique patterns: group in which the diagnosis rate increases with age and group in which the diagnosis rate peaks at a certain age and then decreases. Conclusion: Diagnostic prevalence of psychiatric disorders was different according to age and sex. These patterns should be reflected in the formulation of policies related to mental health and in medical practice for pediatric patients. It is urgent to identify how these patterns change in young adults.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1659-1666
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• 1998

The multicode CDMA systems that are widely studied as an effective transmission methodology in the IMT-2000 systems, employ orthogonal codes to transform high rate data into parallel, low rate data for simultaneous transmission. In this paper, we propose a new multicode CDMA system which achieves the same data rate and processing gain of the conventional systems, while significantly improves bit error rate performance by exploiting a convolutional code with code rate r=1/2 and a bi-orthogonal code. The simulation results for synchronous systems using maximal ratio combining Rake receivers under additive white Gaussian noise and multi-path fading channels, show significant improviements by the proposed system.

• ETRI Journal
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• v.33 no.5
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• pp.752-758
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• 2011

This paper presents a clock and data recovery circuit that supports dual data rates of 5.4 Gbps and 3.24 Gbps for DisplayPort v1.2 sink device. A quarter-rate linear phase detector (PD) is used in order to mitigate high speed circuit design effort. The proposed linear PD results in better jitter performance by increasing up and down pulse widths of the PD and removes dead-zone problem of charge pump circuit. A voltage-controlled oscillator is designed with a 'Mode' switching control for frequency selection. The measured RMS jitter of recovered clock signal is 2.92 ps, and the peak-to-peak jitter is 24.89 ps under $2^{31}-1$ bit-long pseudo-random bit sequence at the bitrate of 5.4 Gbps. The chip area is 1.0 mm${\times}$1.3 mm, and the power consumption is 117 mW from a 1.8 V supply using 0.18 ${\mu}m$ CMOS process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.89-91
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• 2017

A currency exchange is the rate to exchange currencies between different countries and the one of important factors to measure the economic size or status of a country. The currency exchange is affected by various economic or social events and changed dynamically. However, since too many economic and social factors affect the exchange rate and the leverage rate of each factor is so floating, it is difficult to define clearly the relationships between the exchange rate and the specific factor. In this paper, we analyze the data pattern for the exchange rate and news articles. To do this, we counts the frequencies of words presented in the news articles during specific periods and compare the frequencies with the margins of exchange rates.

• East Asian Journal of Business Economics (EAJBE)
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• v.12 no.2
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• pp.19-28
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• 2024

Purpose: In the era of global economic integration, China's doors of openness have widened, leading to increasingly frequent economic and trade exchanges between countries. Exchange rates, as a crucial economic lever for regulating foreign markets, play a vital role in the balanced development of a nation's international trade. Therefore, the relationship between exchange rate fluctuations and foreign trade has garnered widespread attention. Research design, data and methodology: This study utilizes import and export trade data between China and five ASEAN countries from 1998 to 2019. It employs regression analysis to examine the specific impact of the real effective exchange rate of the Renminbi on China's import and export trade with these ASEAN nations. Results: The empirical analysis yields the following conclusions: Firstly, the real effective exchange rate of the Renminbi exhibits a long-term stable relationship with China's import and export trade with the five ASEAN countries. Renminbi appreciation contributes to an increase in export trade volume but is detrimental to import trade. While this conclusion may deviate from classical trade theories, it aligns with the practical realities of China's foreign trade. Secondly, the coefficients before Gross Domestic Product (GDP) all display positive values, indicating that the growth of total economic demand has a stimulating effect on China's import and export trade.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.4
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• pp.115-128
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• 2019

The study aims to investigate the pattern of relationships such as symmetric or asymmetric, between exchange rate and foreign direct investment in Bangladesh by applying Autoregressive Distributed Lagged (ARDL) and nonlinear ARDL. In this study, we employed quarterly data for the period of 1974Q1 to 2016Q4. Data were collected and aggregated from various sources namely, Bangladesh Economic Review published by Ministry of Finance and statistical yearbook published by Bangladesh Bureau of Statistics and an annual report published by Bangladesh Bank. The relationship between exchange rate and FDI inflows attract immense interest in the recent periods, especially for developing countries' perspective. The results of the study ascertain the long run relationship between FDI, exchange rate, monetary policy, and fiscal policy. Considering the asymmetric assumption, the findings from NARDL confirm the existence of a long-run asymmetric relationship in the empirical equation. In the long run, it is observed that positive change that is the appreciation of exchange rate against USD decrease FDI inflows and negative shocks results in grater inflows of FDI, however, the positive shocks produce higher intensity that negative shocks in Exchange rate. For directional causality, the coefficients of error correction term confirm long-run causality, in particular, bidirectional causality unveiled between FDI and exchange rate.

• Journal of Korean Biological Nursing Science
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• v.17 no.3
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• pp.271-276
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• 2015

Purpose: This study was to evaluate the effects on the heart rate and respiration rate of preterm infants when providing auditory stimulation on them. Methods: The design of this study was a nonequivalent control group pretest-posttest design in a quasi experimental study. Forty preterm infants were assigned to experimental and control groups : 20 in the auditory and 20 in the control group. The data were collected from May 2014 to October. The auditory stimulation was created by using an audio music tape provided 20-minute per day for 7 consecutive days. In data analysis, SPSS WIN 21.0 program was utilized for descriptive statistics, repeated measurement anova and Mann-Whitney. Results: General characteristics of the two groups showed no significant differences, thus two groups were found to be homogenous. There were no significant differences in heart rate and respiration rate between the auditory and control groups. Conclusion: The effect of auditory stimulation for 7 days was not effective in decreasing heart rate or respiration rate in premature infants. Therefore, the type and length of music therapy must be developed for the improvement of vital signs in preterm infants who were hospitalized in a neonatal intensive care unit.

• Microbiology and Biotechnology Letters
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• v.17 no.3
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• pp.241-246
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• 1989

Continuous on-line monitoring of cell concentration and growth rate in aerobic batch fermentation process was carried out by analyzing the exhaust gas composition of tormentor with a quadrupole mass spectrometer. From the mass spectrometric analyses of major gaseous components, i.e. $N_2$, $O_2$, $CO_2$ and $H_2O$, and the material balance equations for oxygen and carbon dioxide, oxygen uptake rate (OUR) rind carbon dioxide evolution rate (CER) were instantaneously calculated using a computer (16-bit IBM PC-AT) interfaced to a quadrupole mass spectrometer. The calculated OUR and CER data were used for the estimation of cell concentration and growth rate of Candida utilis during batch culture. It was found that the cell concentration could be satisfactorily estimated from the data of OUR arid CER during the culture and this method could be successfully und for the continuous monitoring of cell growth and growth rate.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.48-53
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• 2006

A methodology is described for predicting the fatigue life of the resistance spot weldment including strain rate effect. Because it is difficult to perform a physical failure test with high strain rate, an analytical method is necessary to get the mechanical properties of various strain rate, To this end, quasi-static tensile-shear tests at several strain rate were performed on spot weldments of SPC. These test provided the empirical data with the strain rate. With these results, we formulated the function of fatigue life prediction using the lethargy coefficient which is the global material property from tensile test. And, we predicted the fatigue life of spot weldment at dynamic strain rate. To confirm this method for fatigue life prediction, analytical results were compared with the experimental fatigue data.