• Smart Structures and Systems
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• v.21 no.3
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• pp.257-262
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• 2018

Vibrational problems in the domestic Small Horizontal Axis Wind Turbines (SHAWT) are due to flap wise vibrations caused by varying wind velocities acting perpendicular to its blade surface. It has been reported that monitoring the structural health of the turbine blades requires special attention as they are key elements of a wind power generation, and account for 15-20% of the total turbine cost. If this vibration problem is taken care, the SHAWT can be made as commercial success. In this work, Shape Memory Alloy (SMA) wires made of Nitinol (Ni-Ti) alloys are embedded into the Glass Fibre Reinforced Polymer (GFRP) wind turbine blade in order to reduce the flapwise vibrations. Experimental study of Nitinol (Ni-Ti) wire characteristics has been done and relationship between different parameters like current, displacement, time and temperature has been established. When the wind turbine blades are subjected to varying wind velocity, flapwise vibration occurs which has to be controlled continuously, otherwise the blade will be damaged due to the resonance. Therefore, in order to control these flapwise vibrations actively, a non-linear current controller unit was developed and fabricated, which provides actuation force required for active vibration control in smart blade. Experimental analysis was performed on conventional GFRP and smart blade, depicted a 20% increase in natural frequency and 20% reduction in amplitude of vibration. With addition of active vibration control unit, the smart blade showed 61% reduction in amplitude of vibration.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.261-261
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• 2010

본 연구에서는 PBMS (Particle Beam Mass Spectrometer)와 ISPM (In-Situ Particle Monitor)을 연계하여 BPSG (Borophosphosilicate Glass) 및 PSG (Phosphosilicate Glass) 박막 증착을 위한 CVD (chemical vapor deposition) 공정 중 발생하는 오염입자 발생특성에 대해 비교 평가하였다. 소스는 TEB (Triethylborate), TEPO (Triethylphosphate) 및 TEOS (Tetraethoxysilane)를 사용하였고, 운반가스 및 반응가스로 He과 $O_2$ 및 $O_3$를 사용하였다. 증착온도와 압력은 각각 $450^{\circ}C$, 200 Torr 이었다. 반응기의 배기라인에 PBMS와 ISPM을 설치하고 500 nm 이하의 입자에 대해 공정단계별 시간에 따른 모니터링 결과 전 공정에 걸쳐 동일한 패턴의 입자발생분포를 보였으며, 특히 PBMS의 경우 ISPM의 입자측정한계인 260 nm 이하의 입자크기도 측정할 수 있었다. 입자발생이 안정적으로 일어나는 증착공정 중 PBMS를 통하여 입자크기를 측정한 결과 BPSG의 경우 약 110 nm, PSG의 경우 약 80 nm의 분포를 나타내었다. 이를 통해 TEB 소스가 배제된 PSG의 경우 BPSG의 경우보다 입자의 성장이 지체됨을 확인하였다. 측정에 대한 신뢰성을 확보하기 위해 PBMS 내의 TEM (Transmission Electron Microscopy) grid를 이용하여 입자를 샘플링 하였고, TEM 분석을 실시한 결과 PBMS 측정결과와 잘 일치하였다. 또한 EDS (Energy Dispersive Spectroscopy) 분석을 통하여 입자성분에 대해 검증하였다.

• Clinical and Experimental Pediatrics
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• v.64 no.10
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• pp.531-537
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• 2021

Background: Multisystem inflammatory syndrome in children (MIS-C) is a new hyperinflammatory variant that evolved during the coronavirus disease 2019 pandemic. Although the precise pathophysiology of MIS-C is uncertain, it is thought to be due to immune dysregulation occurring after recovery from acute infection. Purpose: Our study aimed to analyze the clinical spectrum, laboratory parameters, imaging characteristics, treatment strategies, and short-term outcomes of children with a diagnosis of MIS-C. Methods: This retrospective and prospective observational study included children less than 16 years of age who were admitted to the pediatric unit of a tertiary care teaching hospital in south India between August 2020 to January 2021 with a diagnosis of MIS-C according to World Health Organization criteria. Results: Twenty-one children were included in the analysis; all had fever with variable combinations of other symptoms. The mean age was 6.9 years; 71.4% were male. Gastrointestinal (80.9%) and cardiovascular (80.9%) systems were the most commonly affected. The majority of children had elevated inflammatory markers, and 16 (76.2%) had echocardiographic abnormalities mimicking Kawasaki disease. Eleven children (52.4%) required intensive care admission, 3 (14.3%) required supplemental oxygen, and 4 (19%) required inotropes. Nine (42.9%) were treated with intravenous immunoglobulin alone, 6 (28.6%) with steroids alone, and 3 (14.3%) with steroids and immunoglobulin. The median hospital stay was 6 days; there were no fatalities. Overweight/obesity, elevated ferritin, and mucocutaneous involvement were significantly associated with a prolonged hospital stay (≥7 days). Sixteen children (76.2%) were followed up till now and all of them had no clinical concerns. Conclusion: MIS-C is an emerging disease with variable presentation. A high index of suspicion is necessary for its early identification and appropriate management. Further research is essential for developing optimal treatment strategies.

• Genomics & Informatics
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• v.21 no.2
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• pp.20.1-20.10
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• 2023

Aromatase inhibitors (AI) are drugs that are widely used in treating estrogen receptor (ER)-positive breast cancer patients. Drug resistance is a major obstacle to aromatase inhibition therapy. There are diverse reasons behind acquired AI resistance. This study aims at identifying the plausible cause of acquired AI resistance in patients administered with non-steroidal AIs (anastrozole and letrozole). We used genomic, transcriptomic, epigenetic, and mutation data of breast invasive carcinoma from The Cancer Genomic Atlas database. The data was then separated into sensitive and resistant sets based on patients' responsiveness to the non-steroidal AIs. A sensitive set of 150 patients and a resistant set of 172 patients were included for the study. These data were collectively analyzed to probe into the factors that might be responsible for AI resistance. We identified 17 differentially regulated genes (DEGs) among the two groups. Then, methylation, mutation, miRNA, copy number variation, and pathway analyses were performed for these DEGs. The top mutated genes (FGFR3, CDKN2A, RNF208, MAPK4, MAPK15, HSD3B1, CRYBB2, CDC20B, TP53TG5, and MAPK8IP3) were predicted. We also identified a key miRNA - hsa-mir-1264 regulating the expression of CDC20B. Pathway analysis revealed HSD3B1 to be involved in estrogen biosynthesis. This study reveals the involvement of key genes that might be associated with the development of AI resistance in ER-positive breast cancers and hence may act as a potential prognostic and diagnostic biomarker for these patients.

• Journal of Embryo Transfer
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• v.30 no.4
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• pp.315-317
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• 2015

In vitro culture of murine embryos is an important step for in vitro production systems including in vitro fertilization and generations of genetically engineered mice. M16 is widely used commercialized culture media for the murine embryos. Compared to other media such as potassium simplex optimization medium, commercial M16 (Sigma) media lacks of amino acid, glutamine and antibiotics. In the present study, we optimized M16 based embryo culture system using commercialized antibiotics-glutamine or amino acids supplements. In vivo derived murine zygote were M16 media were supplemented with commercial Penicillin-Streptomycin-Glutamine solution (PSG; Gibco) or MEM Non-Essential Amino Acids solution (NEAA; Gibco) as experimental design. Addition of PSG did not improved cleavage and blastocyst rates. On the other hand, cleavage rate is not different between control and NEAA treated group, however, blastocyst formation is significantly (P<0.05) improved in NEAA treated group. Developmental competence between PSG and NEAA treated groups were also compared. Between two groups, cleavage rate was similar. However, blastocyst formation rate is significantly improved in NEAA treated group. Taken together, beneficial effect of NEAA on murine embryos development was confirmed. Effect of antibiotics and glutamine addition to M16 media is still not clear in the study.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.1
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• pp.21-26
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• 2017

In this paper, we suggest an automated sleep scoring method using machine learning algorithms on accelerometer data from a wristband device. For an experiment, 36 subjects slept for about eight hours while polysomnography (PSG) data and accelerometer data were simultaneously recorded. After the experiments, the recorded signals from the subjects were preprocessed, and significant features for sleep stages were extracted. The extracted features were classified into each sleep stage using five machine learning algorithms. For validation of our approach, the obtained results were compared with PSG scoring results evaluated by sleep clinicians. Both accuracy and specificity yielded over 90 percent, and sensitivity was between 50 and 80 percent. In order to investigate the relevance between features and PSG scoring results, information gains were calculated. As a result, the features that had the lowest and highest information gain were skewness and band energy, respectively. In conclusion, the sleep stages were classified using the top 10 significant features with high information gain.

• Korean journal of food and cookery science
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• v.22 no.2 s.92
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• pp.111-121
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• 2006

The aim of this study was to investigate the possibility of producing goods evaluating the preservation of DSG, PSG, DST and PST, all of which were the most preferred according to the results of sensory evaluation of some sauces made of Demi-glace sauce and a Teriyaki-applied sauce. The pH of normal Demi-glace sauce, at 5.2, was the highest among these sauces. The Teriyaki-applied Demi-glace sauce was the second with pH 5.12 DSG was the lowest. The pH didn't change significantly according to preservation. However, the degree of PSG's pH was lowered by the time period of preservation. DGST didn't changed a lot apart from being a bit morewatery (12.40) after three-week storage. It seemed that the viscosity of the normal sauces, checked after 10 sec, decreased. At 20 sec there were no differences among these sauces. After making 10 applied sauces and evaluating them, DSG, PSG, DST and PST gained the highest preference and the application of Teriyaki sauce was evaluated favorably. According to the preservation test. the sensory evaluation didn't seem to decrease within 2 weeks which demonstrated that the other physicochemical products were unaffected. Therefore, an improvement following more than two-week preservation is expected in t case of rigid store regulation.

• Steel and Composite Structures
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• v.21 no.3
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• pp.573-588
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• 2016

Carbon Fiber Reinforced Plastic (CFRP) and Titanium Alloy (Ti6Al4V) stack, extensively used in aerospace structural components are assembled by fasteners and the holes are made using drilling process. Drilling of stack in one shot is a complicated process due to dissimilarity in the material properties. It is vital to have optimal machining condition and tool geometry for better hole quality and tool life. In this study the tool wear and hole quality were analysed by experimental analysis using three modified twist drills and online tool condition monitoring using Acoustics Emission (AE) sensor. Helix angle and point angle influence tool performance and cutting force. It was found that a tool geometry (TG1) with high helix angle of $35^{\circ}$ with low point angle $130^{\circ}$ results in reduction in thrust force of 150-500 N range but the TG2 also perform almost similar to TG1, but when compared with the AErms voltage generated during drilling it was found that progressive rise in voltage in TG1 is less with respect to TG2 which can be attributed to tool life. In process wear monitoring was done using crest factor as monitoring index. AErms voltage were measured and correlated with the performance of the drills.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1791-1793
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• 2000

본 연구에서는 다결정 실리콘 박막 트랜지스터(poly-Si TFTs)에서의 소오스 및 드레인 영역 형성을 위해 PSG (phosphosilicate glass)와 BSG (borosilicate glass) 박막을 도핑 물질(dopant)로 하여 저온에서 엑시머 레이저(eximer laser)로 활성화하는 공정을 제안한다. 이 실험을 통해 소스 가스인 $PH_3$와 $SiH_4$의 유량비, 레이저 에너지 밀도와 레이저 조사 횟수를 변화시키면서 면저항(sheet resistance)과 불순물의 확산 깊이(diffusion depth)를 성공적으로 조절하였다. 불순물의 확산 깊이와 표면 농도는 레이저 에너지 밀도와 조사 횟수를 증가시킴에 따라 증가하였으며 그 결과 최소 면저항 값은 인(P)의 경우 450$\Omega/\square$을 얻었고 붕소(B)의 경우 1100$\Omega/\square$을 얻었다. 이러한 실험결과는 제안된 방법을 통해 poly-Si TFTs 에서 소오스, 드레인 영역의 도핑 공정을 수행할 수 있음을 보여준다.

• ETRI Journal
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• v.35 no.4
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• pp.697-705
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• 2013

Emerging trends in the area of digital very large scale integration (VLSI) signal processing can lead to a reduction in the cost of the cochlear implant. Digital signal processing algorithms are repetitively used in speech processors for filtering and encoding operations. The critical paths in these algorithms limit the performance of the speech processors. These algorithms must be transformed to accommodate processors designed to be high speed and have less area and low power. This can be realized by basing the design of the auditory filter banks for the processors on digital VLSI signal processing concepts. By applying a folding algorithm to the second-order digital gammatone filter (GTF), the number of multipliers is reduced from five to one and the number of adders is reduced from three to one, without changing the characteristics of the filter. Folded second-order filter sections are cascaded with three similar structures to realize the eighth-order digital GTF whose response is a close match to the human cochlea response. The silicon area is reduced from twenty to four multipliers and from twelve to four adders by using the folding architecture.