• 한국소프트웨어감정평가학회 논문지
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• 제17권1호
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• pp.101-113
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• 2021

본 논문에서는 화자 겹침 시스템을 소개하고 인공지능 분야에서 널리 사용되는 프레임워크에서 이미 구축된 시스템을 전환하는 과정을 고찰하고자 한다. 화자 겹침은 대화 과정에서 두 명 이상의 화자가 동시에 발성하는 것을 말하며, 사전에 화자 겹침을 탐지하여 음성인식이나 화자인식의 성능 저하를 예방할 수 있으므로 많은 연구가 진행되고 있다. 최근 인공지능을 이용한 다양한 응용 시스템의 활용도가 높아지면서 인공지능 프레임워크 (framework) 간의 전환이 요구되고 있다. 그러나 프레임워크 전환 시 각 프레임워크의 고유 특성에 의하여 성능 저하가 관찰되고 있으며 이는 프레임워크 전환을 어렵게 하고 있다. 본 논문에서는 케라스 (Keras) 기반 화자 겹침 시스템을 파이토치 (pytorch) 시스템으로 전환하는 과정을 기술하고 고려해야 할 구성 요소들을 정리하였다. 프레임워크 전환 결과 기존 케라스 기반 화자 겹침 시스템보다 파이토치로 전환된 시스템에서 더 좋은 성능을 보여 체계적인 프레임워크 전환의 기본 연구로서 가치를 지닌다고 할 수 있다.

• 광물과 암석
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• 제35권3호
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• pp.273-281
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• 2022

맨틀 불균질성은 지구 내부의 휘발성 성분의 분포 및 순환과 밀접한 관련이 있으며, 맨틀에서 휘발성 물질의 거동은 규산염암의 유변학적 특성에도 큰 영향을 미친다. 이와 같은 상부맨틀의 물리화학적 특성은 미구조와 유체포유물의 형태로 맨틀 포획암에 기록될 수 있다. 본 논문에서는 미국 리오 그란데 리프트 지역에서 산출되는 페리도타이트 포획암의 미구조와 유체포유물의 특성과 관련된 이전 연구결과들을 요약 및 리뷰하였으며, 이를 통해 이 지역의 상부맨틀의 진화과정과 불균질성에 대해 이해하고자 한다. 리오 그란데 리프트에서 맨틀 포획암이 산출되는 지역은 크게 리프트 중심부인 리프트 축(rift axis) 지역(EB: Elephant Butte, KB: Kilbourne Hole)과 리프트 연변부인 리프트 측면(rift flank) 지역(AD: Adam's Diggings)으로 나눠진다. 전자(EB 및 KB 페리도타이트)의 경우 응력이 낮고 물함량이 적은 조건에서 형성되는 type-A 격자선호방향이 보고되었고, 후자(AD 페리도타이트)의 경우 응력이 낮고 물함량이 많은 조건에서 형성되는 type-C 격자선호방향이 보고된 바 있다. 특히, AD 페리도타이트의 경우 초기(type-1: CO₂-N₂) 및 후기(type-2: CO₂-H₂O)와 같은 최소 두번의 유체 침투 사건이 사방휘석 내에 기록되어있다. 이와 같은 미구조 및 유체포유물에 기록된 상부맨틀의 불균질성은 북미 판과 Farallon 판 사이의 상호작용에 기인한 것으로 추정된다.

• 한국수자원학회논문집
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• 제57권2호
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• pp.73-85
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• 2024

하천과 저수지의 수질을 예측하는 것은 수자원관리를 위해 필요하다. 높은 정확도의 수질 예측을 위해 많은 연구들에서 인공신경망이 활용되었다. 기존 연구들은 매개변수를 탐색하는 인공신경망의 연산자인 옵티마이저로 경사하강법 기반 옵티마이저를 사용하였다. 그러나 경사하강법 기반 옵티마이저는 지역 최적값으로의 수렴 가능성과 해의 저장 및 비교구조가 없다는 단점이 있다. 본 연구에서는 인공신경망을 이용한 수질 예측성능을 향상시키기 위해 개량형 옵티마이저를 개발하여 경사하강법 기반 옵티마이저의 단점을 개선하였다. 본 연구에서 제안한 옵티마이저는 경사하강법 기반 옵티마이저 중 학습오차가 낮은 Adaptive moments (Adam)과 Nesterov-accelerated adaptive moments (Nadam)를 Harmony Search(HS) 또는 Novel Self-adaptive Harmony Search (NSHS)와 결합한 옵티마이저이다. 개량형 옵티마이저의 학습 및 예측성능 평가를 위해 개량형 옵티마이저를 Long Short-Term Memory (LSTM)에 적용하여 국내의 다산 수질관측소의 수질인자인 수온, 용존산소량, 수소이온농도 및 엽록소-a를 학습 및 예측하였다. 학습결과를 비교하면, Nadam combined with NSHS (NadamNSHS)를 사용한 LSTM의 Mean Squared Error (MSE)가 0.002921로 가장 낮았다. 또한, 각 옵티마이저별 4개 수질인자에 대한 MSE 및 R²에 따른 예측순위를 비교하였다. 각 옵티마이저의 평균 순위를 비교하면, NadamNSHS를 사용한 LSTM이 2.25로 가장 높은 것을 확인하였다.

• Parasites, Hosts and Diseases
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• 제48권1호
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• pp.71-73
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• 2010

This cross sectional study was conducted in the city of Taiz, Yemen, during the period from August 2006 to August 2007 in order to investigate the seroprevalence and incidence of toxoplasmosis among apparently healthy children (AHC) and visually and/or hearing disabled children (DC). The seroprevalence was 16.0% among AHC compared to 32.5% among DC. The effect of gender was clear as the seroprevalence rate was significantly higher among females (18.3 and 43.8% for AHC and DC, respectively) than males (13.8 and 25% for AHC and DC, respectively). The seroprevalence was proportionally increased with the age, and the highest rates (20.9 and 53.0%) were reported among the oldest age group (> 10-14 years) for AHC and DC groups, respectively. The incidence rate was also higher (4.2%) in DC group compared to AHC group (2.4%) during 1 year period. These data indicate that the seroprevalence and incidence of toxoplasmosis are significantly higher in DC group than those of AHC group. We need to check further relationship between toxoplasmosis and visual and/or hearing disability.

• 한국수소및신에너지학회논문집
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• 제27권4호
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• pp.341-348
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• 2016

The experiments related on structure and water electrolysis performance of HALE UAV stack were conducted in this study. Anode catalyst $IrRuO_2$ was prepared by Adam's fusion methods as 2~3 nm nano sized particles, and the cathode catalyst was used as commercial product of Premetek. The MEA (membrane electrode assembly) was manufactured by decal methods, anode and anode catalytic layers were prepared by electro-spray. HALE stack was composed of 5 multi-cells as $0.2Nm^3/hr$ hydrogen production rate with hydrogen pressure as 10 bar. The water electrolysis performance was investigated at atmospheric pressure and temperature of $55^{\circ}C$. Best performance of HALE UAV stack was recorded as cell voltage efficiency as 86%.

• Asian-Australasian Journal of Animal Sciences
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• 제33권10호
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• pp.1642-1655
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• 2020

Objective: The aim of this study is to characterize the impact of additional electrical stimulation (AES) and various pre-rigor holding temperatures (for 3 h) on the ageing-potential of hot boned bovine M. longissimus lumborum (LL). Methods: Paired LL loins from 12 bulls were hot-boned within 40 min of slaughter, immediate AES applied and subjected to various holding temperatures (5℃, 15℃, 25℃, and 35℃) for 3 h. Results: AES did not accelerate the rate of rigor attainment, but the 3 h pre-rigor holding temperature did. Shear force values decreased as the pre-rigor holding temperatures increased. AES and holding for 3 h (at 25℃) resulted in higher water-holding capacity. Conclusion: Data confirmed that AES did not influence the various meat quality parameters in the present study, but pre-rigor holding temperature (25℃) alone or in combination with AES resulted in superior meat quality.

• Journal of the Optical Society of Korea
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• 제13권1호
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• pp.15-21
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• 2009

High-order harmonic generation from a solid surface affected by the contrast of a laser pulse was studied using an oscillating mirror model. High-order harmonics generated from solid surfaces have unusual properties such as spectral redshift, and an intensity difference between even- and odd-order harmonics which is not reported for high-order harmonics generated by a gas medium. We confirmed that high-order harmonics from solid surfaces have selectivity of polarization as well as cut-off extension and the enhancement of conversion efficiency proportional to laser intensity. And the principle of operation and the characteristics of a plasma mirror system developed for achieving high contrast laser pulses to pursue the experimental realization of high-harmonic generation from solid surfaces are reported. Energy fluence on the plasma mirrors is tunable between $10\;J/cm^2$ and $1000\;J/cm^2$ and around 1000 shots are available before the plasma mirrors require replacement.

• Physical Therapy Rehabilitation Science
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• 제12권1호
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• pp.19-25
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• 2023

Objective: Patients with scoliosis complain of various symptoms such as muscle imbalance, dysfunction, back pain, abnormal posture and gait abnormality. The most basic treatment for scoliosis is to observe the progress based on conservative treatment. Therefore, in this case report, the effect of cytoskeletal manual therapy (CMT), a soft tissue mobilization technique, on pain intensity, muscle thickness, and pressure pain threshold (PPT) in a patient with scoliosis was investigated. Design: A case report Methods: A 25-year-old male diagnosed with scoliosis visited the Neuromusculoskeletal Science Laboratory with chronic back pain. In the laboratory, scoliosis was confirmed through the X-ray image used for his diagnosis, and it was confirmed again through Adam's forward bending test. Pain, pressure pain threshold and muscle thickness were measured to compare the immediate effects of CMT applied in the laboratory for 40 minutes. Treatments were visited two weeks after the first visit and outcome measures were assessed after a total of two visits. Results: After receiving CMT up to the second session, the pain intensity decreased by 4 points and the screening angle decreased by 15 degrees. Muscle thickness decreased in all but 10 mm on the dominant side of the thoracic spine. All of the PPTs increased, and the greatest increase was 3.1 lb on the dominant side of the thoracic spine. Conclusions: CMT showed positive improvement in pain during trunk flexion, spinal curvature, muscle imbalance, and pressure pain, which is considered as an ancillary treatment option for scoliosis management.

• International Journal of Computer Science & Network Security
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• 제23권5호
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• pp.73-88
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• 2023

Brain tumors can also be an abnormal collection or accumulation of cells in the brain that can be life-threatening due to their ability to invade and metastasize to nearby tissues. Accurate diagnosis is critical to the success of treatment planning, and resonant imaging is the primary diagnostic imaging method used to diagnose brain tumors and their extent. Deep learning methods for computer vision applications have shown significant improvements in recent years, primarily due to the undeniable fact that there is a large amount of data on the market to teach models. Therefore, improvements within the model architecture perform better approximations in the monitored configuration. Tumor classification using these deep learning techniques has made great strides by providing reliable, annotated open data sets. Reduce computational effort and learn specific spatial and temporal relationships. This white paper describes transfer models such as the MobileNet model, VGG19 model, InceptionResNetV2 model, Inception model, and DenseNet201 model. The model uses three different optimizers, Adam, SGD, and RMSprop. Finally, the pre-trained MobileNet with RMSprop optimizer is the best model in this paper, with 0.995 accuracies, 0.99 sensitivity, and 1.00 specificity, while at the same time having the lowest computational cost.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.1091-1099
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• 2024

Fluoride-salt-cooled High-temperature Reactor (FHR) is a promising nuclear reactor technology. Among many challenges presented by the molten fluoride salts is the corrosion of salt-facing structural components. Higher moisture contents, in the FLiNaK (LiF-NaF-KF, 46.5-11.5-42 mol%) salt, aggravate intergranular corrosion and pitting for the given alloys. Therefore, several thermal dehydration tests of FLiNaK salt were performed with a batch size suitable for thermal-hydraulic experiments. Thermogravimetric Analysis (TGA) was performed for the three constituent fluoride salts individually. Preliminary thermal dehydration plans were then proposed for NaF and KF salts based on the TGA curves. However, the dehydration process may not be required for LiF since its low mass loss (<1.3 wt%). To evaluate the performance of these thermal dehydration plans, a batch-scale salt dehydration test facility was designed and constructed. The preliminary thermal dehydration plans were tested by varying the heating rates, target temperature, and holding time. The sample mass loss data showed that the high temperatures (>500 ℃) were necessary to remove a significant amount of moisture (>1 wt%) from NaF salt, while relatively low temperatures (around 300 ℃) with a long holding time (>10 h) were sufficient to remove most of the moisture from KF salt.