• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.6
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• pp.726-732
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• 2019

In this study, we proposed an asymmetric differential inductor to improve the linearity of differential power amplifiers. Considering the phase error between differential signals of the differential amplifier, the location of the center tap of the differential inductor was modified to minimize the error. As a result, the center tap was positioned asymmetrically inside the differential inductor. With the asymmetric differential inductor, the AM-to-AM and AM-to-PM distortions of the amplifier were suppressed. To confirm the feasibility of the inductor, we designed a 2.4 GHz differential CMOS PA for IEEE 802.11n WLAN applications with a 64-quadrature amplitude modulation (QAM), 9.6 dB peak-to-average power ratio (PAPR), and a bandwidth of 20 MHz. The designed power amplifier was fabricated using the 180-nm RF CMOS process. The measured maximum linear output power was 17 dBm, whereas EVM was 5%.

• Journal of Korean Academy of Nursing
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• v.49 no.1
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• pp.59-68
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• 2019

Purpose: This study evaluated the psychometric properties of the Korean version of Yale Food Addiction Scale for Children (YFAS-C). Methods: Participants were 419 young adolescent students (11~15 years old). The content validity of the expert group was calculated as the content validity index (CVI) after the translation and reverse translation process of the 25 items of the YFAS-C. The multitrait-multimethod matrix (MTMM) method was used to verify the construct validity; the generalized linear model (GLM) was used to evaluate the concurrent and incremental validity. Reliability was calculated as Kuder-Richardson-20 (KR-20) and Spearman-Brown coefficients. Results: The CVI of the 25 items was greater than the item-level CVI .80 and the scale-level CVI .90. The Korean version of YFAS-C had verified convergent validity in emotional eating and external eating and discriminant validity in restrained eating. In addition, it had verified concurrent validity in emotional eating and external eating. Finally the incremental validity of the Korean version of YFAS-C was statistically significant on BMI. Reliability was KR-20 ${\alpha}=.69$ and the Spearman-Brown coefficient was .64. Conclusion: The Korean version of YFAS-C is a valid and reliable scale for measuring the severity of food addiction; it can be a useful scale for preventing obesity by predicting food addiction early.

• Journal of Energy Engineering
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• v.28 no.1
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• pp.1-9
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• 2019

In the flue gas desulfurization process of the coal-fired power plant, the grinding efficiencies of the limestone as the sorbent for desulfurization were compared after BWI and HGI measurements. As a result, the grinding index of the domestic desulfurization limestone were linear inversely proportional relationship with decreasing BWI was observed with increasing HGI. There was a difference in grinding efficiency depending on the chemical composition and crystal structure. Therefore, it is considered that when grinding ability of limestone is measured, the grinding property of the sample can be confirmed even by using HGI which can be measured more easily than BWI which is difficult to measure and takes a long time. The desulfurization efficiency can be improved by selective utilization of limestone depending on the crushing characteristics.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.533-536
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• 2016

This paper describes a vibrational energy harvesting circuit with MPPT control. A high-performance AC-DC converter of which the efficiency is improved by using body-bias technique and bulk-driven technique is proposed and applied for the vibrational energy harvesting circuit design. MPPT (Maximum Power Point Tracking) control function is implemented using the linear relationship between the open-circuit voltage of a vibrational device and its MPP voltage. The designed MPPT control circuit traces the maximum power point by periodically sampling the open circuit voltage of a vibrational device, makes the reference voltages using sampled voltage and delivers the maximum available power to load. The proposed circuit is designed with a $0.35{\mu}m$ CMOS process, and the chip area is $1.21mm{\times}0.98mm$.

• IEMEK Journal of Embedded Systems and Applications
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• v.14 no.5
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• pp.277-286
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• 2019

In this paper, we propose an efficient hyperplane generation technique to classify human activity from combination of events and sequence information obtained from multiple-event sensors. By generating hyperplane efficiently, our machine learning algorithm classify with less memory and run time than the LSVM (Linear Support Vector Machine) for embedded system. Because the fact that light weight and high speed algorithm is one of the most critical issue in the IoT, the study can be applied to smart home to predict human activity and provide related services. Our approach is based on reducing numbers of hyperplanes and utilizing robust string comparing algorithm. The proposed method results in reduction of memory consumption compared to the conventional ML (Machine Learning) algorithms; 252 times to LSVM and 34,033 times to LSTM (Long Short-Term Memory), although accuracy is decreased slightly. Thus our method showed outstanding performance on accuracy per hyperplane; 240 times to LSVM and 30,520 times to LSTM. The binarized image is then divided into groups, where each groups are converted to binary number, in order to reduce the number of comparison done in runtime process. The binary numbers are then converted to string. The test data is evaluated by converting to string and measuring similarity between hyperplanes using Levenshtein algorithm, which is a robust dynamic string comparing algorithm. This technique reduces runtime and enables the proposed algorithm to become 27% faster than LSVM, and 90% faster than LSTM.

• Food Science of Animal Resources
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• v.39 no.3
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• pp.459-473
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• 2019

Lactobacillus rhamnosus GG (LGG) has low resistance to low pH and bile salt in the gastrointestinal juice. In this study, the gel made from whey protein concentrate (WPC) and pullulan (PUL) was used as the wall material to prepare the microencapsulation for LGG protection. The gelation process was optimized and the properties of gel were also determined. The results showed the optimal gel was made from 10% WPC and 8.0% PUL at pH 7.5, which could get the best protective effect; the viable counts of LGG were 6.61 Log CFU/g after exposure to simulated gastric juice (SGJ) and 9.40 Log CFU/g to simulated intestinal juice (SIJ) for 4 h. Sodium dodecyl sulphite polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that the WPC-PUL gel had low solubility in SGJ, but dissolved well in SIJ, which suggested that the gel can protect LGG under SGJ condition and release probiotics in the SIJ. Moreover, when the gel has highest hardness and water-holding capacity, the viable counts of LGG were not the best, suggesting the relationship between the protection and the properties of the gel was non-linear.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.5
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• pp.197-205
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• 2018

In this research, tricycle vehicle simulation based on multi-body environment has been introduced. Mathematical model of tricycle vehicle was developed. In this research the left and right wheel speed are calculated based on the rear steering angle and velocity. The kinematic model for the three - wheel drive system was completed and the results were analyzed using the actual vehicle drawings. Through simulink vehicle performance on linear and rotation movement were simulated. Using the mathematical model the control system can be applied directly to the tricycle vehicle. The simulation result shows that the proposed vehicle model is successfully represent the movement characteristics of the real vehicle. This model assists the vehicle developer to create the controller and understand the vehicle during the development process.

• Imaging Science in Dentistry
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• v.49 no.2
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• pp.123-130
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• 2019

Purpose: This study was conducted to characterize the relationship of the angulation between the tooth root axis and alveolar bone axis with anterior alveolar(AA) arch forms and sagittal root position (SRP) in the anterior esthetic region using cone-beam computed tomography (CBCT) images. Materials and Methods: CBCT images that met the inclusion and exclusion criteria were categorized using a recent classification of AA arch forms and a SRP classification. Then, the angulation of the root axis and the alveolar bone axis was measured using mid-sagittal CBCT images of each tooth. The relationships of the angulation with each AA arch form and SRP classification were evaluated using 1-way analysis of variance and a linear regression model. Results: Ninety-eight CBCT images were included in this study. SRP had a greater influence than the AA arch form on the angulation of the root axis and the alveolar bone axis(P<0.05). However, the combination of AA arch form and SRP was more predictive of the angulation of the root axis and the alveolar bone axis than either parameter individually. Conclusion: The angulation of the root axis and alveolar bone axis demonstrated a relationship with the AA arch form and SRP in teeth in the anterior esthetic region. The influence of SRP was greater, but the combination of both parameters was more predictive of root-to-bone angulation than either parameter individually, implying that clinicians should account for both the AA arch form and SRP when planning implant placement procedures in this region.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.5
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• pp.607-613
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• 2019

Objective: Intramuscular fat (IMF) content plays an important role in meat quality. Identification of single nucleotide polymorphisms (SNPs) and genes related to pig IMF, especially using pig populations with high IMF content variation, can help to establish novel molecular breeding tools for optimizing IMF in pork and unveil the mechanisms that underlie fat metabolism. Methods: We collected muscle samples of 453 Chinese Lulai black pigs, measured IMF content by Soxhlet petroleum-ether extraction method, and genotyped genome-wide SNPs using GeneSeek Genomic Profiler Porcine HD BeadChip. Then a genome-wide association study was performed using a linear mixed model implemented in the GEMMA software. Results: A total of 43 SNPs were identified to be significantly associated with IMF content by the cutoff p<0.001. Among these significant SNPs, the greatest number of SNPs (n = 19) were detected on Chr.9, and two linkage disequilibrium blocks were formed among them. Additionally, 17 significant SNPs are mapped to previously reported quantitative trait loci (QTLs) of IMF and confirmed previous QTLs studies. Forty-two annotated genes centering these significant SNPs were obtained from Ensembl database. Overrepresentation test of pathways and gene ontology (GO) terms revealed some enriched reactome pathways and GO terms, which mainly involved regulation of basic material transport, energy metabolic process and signaling pathway. Conclusion: These findings improve our understanding of the genetic architecture of IMF content in pork and facilitate the follow-up study of fine-mapping genes that influence fat deposition in muscle.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.2
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• pp.55-62
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• 2021

This study aims to reduce the rancid odor generated during the fermentation process of kimchi by inserting zinc oxide (ZnO) into an inorganic porous material with a high surface area to decompose or adsorb the fermentation odor. ZnO activated by the presence of moisture exhibits decomposition of rancid odors. Mixed with Titanium dioxide (TiO₂), a photocatalyst. To manufacture the packaging liner used in this study, NaOH, ZnCl₂, and TiO₂ powder were placed in a tank with diatomite and water. The sludge obtained via a hydrothermal ultrasonication synthesis was sintered in an oven. After being pin-milled and melt-blended, the powders were mixed with linear low-density polyethylene (L-LDPE) to make a masterbatch (M/B), which was further used to manufacture liners. A gas detector (GasTiger 2000) was used to investigate the total amount of sulfur compounds during fermentation and determine the reduction rate of the odor-causing compounds. The packaging liner cross-section and surface were investigated using a scanning electron microscope-energy dispersive X-ray spectrometer (SEM-EDS) to observe the adsorption of sulfur compounds. A variety of sulfur compounds associated with the perceived unpleasant odor of kimchi were analyzed using gas chromatography-mass spectrometry (GC-MS). For the analyses, kimchi was homogenized at room temperature and divided into several sample dishes. The performance of the liner was evaluated by comparing the total area of the GC-MS signals of major off-flavor sulfur compounds during the five days of fermentation at 20℃. As a result, Nano-grade inorganic compound liners reduced the sulfur content by 67 % on average, compared to ordinary polyethylene (PE) foam liners. Afterwards SEM-EDS was used to analyze the sulfur content adsorbed by the liners. The findings of this study strongly suggest that decomposition and adsorption of the odor-generating compounds occur more effectively in the newly-developed inorganic nanocomposite liners.