• 전자공학회논문지A
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• 제31A권6호
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• pp.1-8
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• 1994

In this paper, in order to apply the idea MDPSK to TCM, we use signal set expansion and set partition by phase differences. Through this we propose the trellis-coded MDPSK. And the Viterbi decoder containing branch metrics of the squared Euclidean distance of the Lth order phase difference as well as the first order phase difference is introduced in order to improve the bit error rate(BER) in the differential detection of the trellis-coded MDPSK. The proposed Viterbi decoder is conceptually same to the sliding multiple symbol dection method which uses the branch metric with the first and Lth order phase differences. We investigate the performance of the uncoded DQPSK and the trallis-coded D8PSK in additive white Gaussian noise (AWGN) through the Monte Carlo simulation under the two cases of using and not using the Lth order phase difference metric. The study shows that trellis-coded 8DPSK is an attractive scheme for power and bandlimited systems while also improving the BER performance when the Viterbi decoder is employed to the Lth order phase order difference metric. This performance improvement has been obtained without sacrificing the bandwidth or the power efficiency.

• 한국통신학회논문지
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• 제21권2호
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• pp.483-494
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• 1996

In this paper, we proposed the receive decoder and Virterbi algorithm with sliding multiple symbol detection using MLSE. the informationis transmitted by the phase difference of the adjacent channel signal at the .pi./4 shift QPSK. In order to apply the .pi./4 shift QPSK to TCM, we use the signal set expansion and the signal set partition by the phase differences. And the Viterbi decoder containing branch mertrice of the squared Euclidean distance of the first, second and Lth order phase difference is introduced in order to extract the information in the differential detection of the Trellis-Coded .pi./4 shift QPSK. The proposed Viterbi decoder and receiver are conceptually same to the sliding multiple symbol detection method using the MLSE. By uisng this method, the study shows that the Trellis-Coded .pi./4 shift QPSK is an attractive scheme for the power and the bandimited systems while also improving the BER performance when the Viterbi decoder is employed to the Lth order phase difference metrics.

• 한국전자파학회지:전자파기술
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• 제3권2호
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• pp.30-38
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• 1992

본 논문에서는 $\pi$/4 shift QPSK에 Trellis 부호화된 변조 기볍(Trellis-Coded Modulation, TCM)을 적용시키기위하여 $\pi$/8 shift 8PSK를 제안하고 위상차에의한 신호 집합 확장과 신호 집합 분할을 수행하 는 trellis 부호화된 $\pi$/8 shift 8PSK를 제안한다. 또한 BER(Bit Error Rate) 성능을 향상시키기위하여 제l차 위상차뿐만아니라 제L차 위상차의 자승 유클리드 거리블 메트릭(Branch Metric)으로 갖는 비터 비 디코더(Viterbi decoder)를 설계한다. 그리고 $\pi$/4 shift QPSK, trellis 부호화된 $\pi$/8 shift 8PSK와 제L차 위상차의 자승 유클리드 거리를 메트릭(Branch Metric)으로 갖는 trellis 부호화된 $\pi$/8 shift 8 8PSK의 BER 특성을 AWGN과 다경로 페이딩 채널에서 Monte Carlo 시플레이션을 통해 알야본다. 제안된 알고리즘은MDPSK에도 적용될 수 있다.

• Journal of Periodontal and Implant Science
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• 제44권3호
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• pp.141-146
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• 2014

Purpose: Peri-implantitis and periodontitis are inflammatory and infectious diseases of implant and tooth-supporting tissues. Recently, the role of gene polymorphisms of immune response components in the relevant pathogenesis has been investigated. The present study was the first to evaluate the relationship between two known single nucleotide polymorphisms (SNPs) of the receptor activator of nuclear factor kappa-${\beta}$ (RANK) gene (rs3018362 and rs35211496) in chronic periodontitis and peri-implantitis patients in an Iranian population. Methods: Eighty-one periodontally healthy patients, 38 patients with peri-implantitis, and 74 patients with chronic periodontitis were enrolled in this study. DNA was extracted from blood arm vein samples by using Miller's salting out technique according to the manufacturer's instructions given in the extraction kit. The concentration of DNA samples was measured using a spectrophotometer. The genetic polymorphisms of the RANK gene were evaluated using a competitive allele specific polymerase chain reaction (KBioscience allele specific PCR) technique. Differences in the frequencies of genotypes and alleles in the diseased and healthy groups were analyzed using chi-squared statistical tests (P<0.05). Results: Analysis of rs35211496 revealed statistically significant differences in the expression of the TT, TC, and CC genotypes among the three groups (P=0.00). No statistically significant difference was detected in this respect between the control group and the chronic periodontitis group. The expression of the GG, GA, and AA genotypes and allele frequencies (rs3018362) showed no statistically significant difference among the three groups (P=0.21). Conclusions: The results of this study indicate that the CC genotype of the rs35211496 RANK gene polymorphism was significantly associated with peri-implantitis and may be considered a genetic determinant for peri-implantitis, but this needs to be confirmed by further studies in other populations.

• 한국보건간호학회지
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• 제32권1호
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• pp.44-55
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• 2018

Purpose: This study was conducted to identify factors influencing fundus examination to prevent diabetic retinopathy in diabetes patients to provide basic data to improve screening rates of fundus examinations. Methods: Raw data from the 6th Korea National Health and Nutrition Examination Survey, which is a cross-sectional and nationally representative survey, were used in this study. The subjects of the study were 1,029 adult diabetes patients over the age of 19 years who had been diagnosed with diabetes. The demographic characteristics, diabetes and disease-related characteristics and health behavior characteristics according to the fundus examinations were analyzed by the chi-squared test and logistic regression analyses were used to examine the factors influencing fundus examination. Results: A total of 333 patients underwent fundus examination at a screening rate of 32.2%. We identified factors influencing fundus examination in patients with diabetes as level of education, type of diabetes care, period of diabetes, and smoking. Conclusion: A multiple approach is required to raise the low screening rate of fundus examination, including specialized education for low-education groups. Moreover, nursing intervention should focus on subjects who do not engage in insulin and oral hypoglycemic agents and with diabetes for a long period.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1261-1268
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• 2013

This study proposes a voltage and reactive coordinative control strategy with distributed generator (DG) in a distribution power system. The aim is to determine the optimum dispatch schedules for an on-load tap changer (OLTC), distributed generator settings and all shunt capacitor switching on the load and DG generation profile in a day. The proposed method minimizes the real power losses and improves the voltage profile using squared deviations of bus voltages. The results indicate that the proposed method reduces the real losses and voltage fluctuations and improve receiving power factor. This paper proposes coordinated voltage and reactive power control methods that adjust optimal control values of capacitor banks, OLTC, and the AVR of DGs by using a voltage sensitivity factor (VSF) and dynamic programming (DP) with branch-and-bound (B&B) method. To avoid the computational burden, we try to limit the possible states to 24 stages by using a flexible searching space at each stage. Finally, we will show the effectiveness of the proposed method by using operational cost of real power losses and voltage deviation factor as evaluation index for a whole day in a power system with distributed generators.

• ETRI Journal
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• 제26권2호
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• pp.101-111
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• 2004

This paper presents a near-optimum blind decision feedback equalizer (DFE) for the receivers of Advanced Television Systems Committee (ATSC) digital television. By adopting a modified trellis decoder (MTD) with a trace- back depth of 1 for the decision device in the DFE, we obtain a hardware-efficient, blind DFE approaching the performance of an optimum DFE which has no error propagation. In the MTD, the absolute distance is used rather than the squared Euclidean distance for the computation of the branch metrics. This results in a reduction of the computational complexity over the original trellis decoding scheme. Compared to the conventional slicer, the MTD shows an outstanding performance improvement in decision error probability and is comparable to the original trellis decoder using the Euclidean distance. Reducing error propagation by use of the MTD in the DFE leads to the improvement of convergence performance in terms of convergence speed and residual error. Simulation results show that the proposed blind DFE performs much better than the blind DFE with the slicer, and the difference is prominent at the trellis decoder following the blind DFE.

• Structural Engineering and Mechanics
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• 제83권2호
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• pp.259-272
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• 2022

The branch of electronics that uses an organic solar cell or conductive organic polymers in order to yield electricity from sunlight is called photovoltaic. Regarding this crucial issue, an artificial intelligence-based predictor is presented to investigate the vibrational behavior of the organic solar cell. In addition, the generalized differential quadrature method (GDQM) is utilized to extract the results. The validation examination is done to confirm the credibility of the results. Then, the deep neural network with fully connected layers (DNN-FCL) is trained by means of Adam optimization on the dataset whose members are the vibration response of the design-points. By determining the optimum values for the biases along with weights of DNN-FCL, one can predict the vibrational characteristics of any organic solar cell by knowing the properties defined as the inputs of the mentioned DNN. To assess the ability of the proposed artificial intelligence-based model in prediction of the vibrational response of the organic solar cell, the authors monitored the mean squared error in different steps of the training the DNN-FCL and they observed that the convergency of the results is excellent.

• 한국정보통신학회논문지
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• 제4권3호
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• pp.517-526
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• 2000

본 논문에서는 직접대역확산통신시스템에서 코딩 이득을 향상시키고자 다중 심벌 검파를 수행하는 트렐리스 부호화 변조를 적용하였다. $MDPSK(\pi/4 shift QPSK)$를 트렐리스 부호화된 직접대역확산시스템 적용하고 정보가 인접한 채널 신호의 위상차에 전송된다는 것을 이용하여 1차 위상차 뿐만 아니라 다중위상차를 추출한다. BER특성을 향상시키기 위해, 이러한 다중 위상차를 이용하여 $MDPSK(\pi/4 shift QPSK)$에서 다중 심벌 검파를 수행하는 트렐리스 부호화된 직접대역확산시스템의 비터비 디코더 알고리듬을 설계하여 향상된 코딩 이득을 얻고자 한다. 이러한 시스템을 직접대역확산통신시스템에 적용하였을 때 얻을 수 있는 코딩 이득은 시뮬레이션 결과, AWGN채널에서 TCM의 콘볼류션부호화기의 상태수 4, 8, 16에 따라 3-4dB 정도의 성능향상이 있으며, 레일레이 페이딩 채널에서는 4-5dB정도의 성능 향상이 있음을 알 수 있다. 일반적으로 상태수가 증가할수록 더 큰 코딩 이득을 얻을 수 있다.

• Tuberculosis and Respiratory Diseases
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• 제82권3호
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• pp.194-200
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• 2019

Background: Tuberculosis (TB) is a major infectious disease in South Korea causing substantial disease burden, particularly in the elderly. This study aimed to identify the case detection rate of mobile TB screening for the elderly conducted in the Jeollanam-do region and to analyze risk factors of active TB. Methods: We screened the elderly population (${\geq}65$ years old) in Jeollanam-do from August to December 2017. Chest radiography was performed for all participants. Participants with TB presumptive signs were asked to submit sputum specimen(s). Sputum smear, culture, and polymerase chain reaction analyses were performed. Cascade analysis, chi-squared tests, and Fisher exact tests were used to evaluate screening performance. Results: In total, 12,402 participants were screened, and 211 (1.7%) were suspected to have active TB; 181 of the suspected patients (85.8%) underwent sputum smear test, and 16 (8.8%) patients were confirmed to have TB. The TB prevalence among the elderly was bacteriologically confirmed to be 129 per 100,000 individuals, which was similar to national TB notification data for the same age groups. The proportion of active TB cases increased with age, and differed based on sex and past TB history. However, TB-related symptoms, comorbidity status, and TB screening history within 12 months were not predictive of active TB. Conclusion: This study identified that the prevalence rate was similar to national TB notification data from the same age groups. Periodic, community-based, systematic TB screening among the elderly population is recommended.