• International Journal of Computer Science & Network Security
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• 제23권11호
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• pp.133-141
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• 2023

This work take deeper analysis of Adaptive Moment Estimation (Adam) and Adam with Weight Decay (AdamW) implementation in real world text classification problem (DGA Malware Detection). AdamW is introduced by decoupling weight decay from L2 regularization and implemented as improved optimizer. This work introduces a novel implementation of AdamW variant as AdamW+ by further simplifying weight decay implementation in AdamW. DGA malware detection LSTM models results for Adam, AdamW and AdamW+ are evaluated on various DGA families/ groups as multiclass text classification. Proposed AdamW+ optimizer results has shown improvement in all standard performance metrics over Adam and AdamW. Analysis of outcome has shown that novel optimizer has outperformed both Adam and AdamW text classification based problems.

• 한국방사선학회논문지
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• 제18권1호
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• pp.21-26
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• 2024

You only look once v5 (YOLOv5)는 객체 검출 과정에 우수한 성능을 보이고 있는 딥러닝 모델 중 하나다. 그러므로 본 연구의 목적은 양전차방출단층촬영 팬텀 영상에서 다양한 하이퍼 파라미터에 따른 YOLOv5 모델의 성능을 평가했다. 데이터 세트는 500장의 QIN PET segmentation challenge로부터 제공되는 오픈 소스를 사용하였으며, LabelImg 소프트웨어를 사용하여 경계박스를 설정했다. 학습의 적용된 하이퍼파라미터는 최적화 함수 SDG, Adam, AdamW, 활성화 함수 SiLu, LeakyRelu, Mish, Hardwish와 YOLOv5 모델 크기에 따라 nano, small, large, xlarge다. 학습성능을 평가하기 위한 정량적 분석방법으로 Intersection of union (IOU)를 사용하였다. 결과적으로, AdmaW의 최적화 함수, Hardwish의 활성화 함수, nano 크기에서 우수한 객체 검출성능을 보였다. 결론적으로 핵의학 영상에서의 객체 검출 성능에 대한 YOLOV5 모델의 유용성을 확인하였다.

• 한국방사선학회논문지
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• 제17권5호
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• pp.709-715
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• 2023

본 연구의 목적은, U-net 딥러닝 모델을 이용하여 CT 영상에서의 노이즈 감소 효과를 다양한 하이퍼 파라미터를 적용하여 평가하였다. 노이즈가 포함된 입력 영상 생성을 위하여 Gaussian 노이즈를 적용하였고, 총 1300장의 CT 영상에서 train, validation, test 셋의 비율을 8:1:1로 유지하여 U-net 모델을 적용하여 학습하였다. 연구에서 적용된 하이퍼파라미터는 최적화 함수 Adagrad, Adam, AdamW와 학습횟수 10회, 50회, 100회와 학습률 0.01, 0.001, 0.0001을 적용하였으며, 최대 신호 대 잡음비와 영상의 변동계수 값을 계산하여 정량적으로 분석하였다. 결과적으로 U-net 딥러닝 모델을 적용한 노이즈 감소는 영상의 질을 향상시킬 수 있으며 노이즈 감소 측면에서 유용성을 입증하였다.

• Journal of Power Electronics
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• 제12권1호
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• pp.33-39
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• 2012

This paper describes operating and capacitor voltage balancing of the modular multilevel converter. The paper focuses on sizing of the cell capacitor and establishes approximate expressions for the capacitor voltage. Simulations and experiments results obtained from three-level modular converter are used to demonstrate its viability in medium voltage applications. It is shown that the modular converter can operate over the full modulation index linear range independent of load power factor.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.637-640
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• 2006

DuPont Teijin Films (DTF) have developed engineered substrates specifically for the flexible electronics market. $Teonex^{(R)}Q65$ is a biaxially oriented crystalline polyester with a tailored surface and it is emerging as a competitive material for the base substrate in OLED displays and active matrix backplanes. Given the dimensional reproducibility requirements in the display applications, uncontrolled moisture absorption during the processing cycle could potentially be far more significant than the inherent shrinkage of the base substrate. Understanding these effects and optimising the processing steps involved in device manufacture will be critical to achieving the ultimate performance that can be achieved with the base substrate.

• Rapid Communication in Photoscience
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• 제1권2호
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• pp.58-58
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• 2012

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• 제25권3호
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• pp.311-315
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• 2023

Anterior communicating artery aneurysms are the most common intracranial aneurysm and have a high risk of rupture which can lead to morbidity and mortality. Traditionally, intracranial aneurysms were treated by clipping with neurosurgical access. However, certain patients may prefer less invasive approaches or not represent open surgical candidates. Flow diverters, including flow-redirection endoluminal devices (FRED), are new-generation stents that are placed endovascularly by transfemoral or transradial access. Recent studies have demonstrated that FRED is both safe and effective, with complete occlusion of aneurysms in over 90% of patients. This case highlights an interesting phenomenon of post-flow diversion circulatory remodeling, where flow diverter treatment can alter the circle of Willis anatomy and physiology.

• Smart Structures and Systems
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• 제19권2호
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• pp.225-236
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• 2017

Railroad bridges in North America are an integral but aging part of the railroad network and are typically only monitored using visual inspections. When quantitative information is required for assessment, railroads often monitor bridges using accelerometers. However without a sensor to directly measure displacements, it is difficult to interpret these results as they relate to bridge performance. Digital Image Correlation (DIC) is a non-contact sensor technology capable of directly measuring the displacement of any visible bridge component. In this research, a railroad bridge was monitored under load using DIC and accelerometers. DIC measurements are directly compared to serviceability limits and it is observed that the bridge is compliant. The accelerometer data is also used to calculate displacements which are compared to the DIC measurements to assess the accuracy of the accelerometer measurements. These measurements compared well for zero-mean lateral data, providing measurement redundancy and validation. The lateral displacements from both the accelerometers and DIC at the supports were then used to determine the source of lateral displacements within the support system.

• 한국지구과학회지
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• 제44권4호
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• pp.275-290
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• 2023

Structural inversion refers to the reverse reactivation of extensional faults that influence basin shortening accommodated by contractional faults or folds. On the Korean peninsula, Miocene inversion structures have been found, but the Cretaceous rocks on Geoje Island may have undergone inversion as early as the Upper Cretaceous. To evaluate the structural inversion on Geoje Island, located on the eastern side of South Korea, and to determine the effects of preexisting weakness zones, field-based geometric and kinematic analyses of faults were performed. The lithology of Geoje Island is dominated by hornfelsified shale, siltstone, and sandstone in the Upper-Cretaceous Seongpori formation. NE and NW-oblique normal faults, conjugate strike-slip (NW-sinistral transpressional and E-W-dextral transtensional) faults, and NE-dextral transpressional faults are the most prominent structural features in Geoje Island. Structural inversion on Geoje Island was evidenced by the sinistral and dextral transpressional reactivation of the NW and NE-trending oblique normal faults respectively, under WNW-ESE/NW-SE compression, which was the orientation of the compressive stress during the Late Cretaceous to Early Cenozoic.

• 논리연구
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• 제12권2호
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• pp.31-58
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• 2009

이 글은 직설법 조건문에 대한 스톨네이커의 의미론을 제시하고 옹호한다. 직설법적 조건문에 대한 스톨네이커의 가능세계의 의미론은 표준적인 가능세계와 조건문에 대한 선택함수 의미론, 그리고 직설법적 조건문에만 적용되도록 선택함수를 제한하는 화용론적 원리로 구성된다. 그의 의미론에 따르면, 직설법적 조건문은 강한 진리조건을 갖기 때문에 논란없는 원리는 받아들이지만, 이행원리가 보편적으로 성립한다는 것은 거부한다. 그럼에도 이행원리가 성립하는 경우가 있을 수 있는데 그것이 어떻게 가능한지를 설명함으로써 직설법적 조건문에 대해서 우리가 갖는 일반적인 직관을 잘 설명하는 이론임을 보인다. 또한 이 글은 스톨네이커의 이론에 대하여 제기되는 아담스주의적 비판과 기바드 현상의 문제에 대해서 답하고, 스톨네이커의 의미론은 지나치게 맥락의존적이라는 비판에 답함으로써 직설법적 조건문에 대한 가장 받아들일 만한 이론임을 주장한다.