• 한국멀티미디어학회논문지
• /
• 제24권7호
• /
• pp.849-859
• /
• 2021

Prostate cancer (PCa) is a fatal disease that occurs in men. In general, PCa cells are found in the prostate gland. Early diagnosis is the key to prevent the spreading of cancers to other parts of the body. In this case, deep learning-based systems can detect and distinguish histological patterns in microscopy images. The histological grades used for the analysis were benign, grade 3, grade 4, and grade 5. In this study, we attempt to use transfer learning and fine-tuning methods as well as different model architectures to develop and compare the models. We implemented MobileNet, ResNet50, and DenseNet121 models and used three different strategies of freezing layers techniques of fine-tuning, to get various pre-trained weights to improve accuracy. Finally, transfer learning using MobileNet with the half-layer frozen showed the best results among the nine models, and 90% accuracy was obtained on the test data set.

• The Journal of Advanced Prosthodontics
• /
• 제14권2호
• /
• pp.122-132
• /
• 2022

PURPOSE. This in-vitro analysis aimed to compare the intaglio trueness, the antagonist's wear volume loss, and fracture load of various single-unit zirconia prostheses fabricated by different manufacturing techniques. MATERIALS AND METHODS. Zirconia crowns were prepared into four different groups (n = 14 per group) according to the manufacturing techniques and generations of the materials. The intaglio surface trueness (root-mean-square estimates, RMS) of the crown was measured at the marginal, axial, occlusal, and inner surface areas. Half of the specimens were artificially aged in the chewing simulator with 120,000 cycles, and the antagonist's volume loss after aging was calculated. The fracture load for each crown group was measured before and after hydrothermal aging. The intaglio trueness was evaluated with Welch's ANOVA and the antagonist's volume loss was assessed by the Kruskal-Wallis tests. The effects of manufacturing and aging on the fracture resistance of the tested zirconia crowns were determined by two-way ANOVA. RESULTS. The trueness analysis of the crown intaglio surfaces showed surface deviation (RMS) within 50 ㎛, regardless of the manufacturing methods (P = .053). After simulated mastication, no significant differences in the volume loss of the antagonists were observed among the zirconia groups (P = .946). The manufacturing methods and simulated chewing had statistically significant effects on the fracture resistance (P < .001). CONCLUSION. The intaglio surface trueness, fracture resistance, and antagonist's wear volume of the additively manufactured 3Y-TZP crown were clinically acceptable, as compared with those of the 4Y- or 5Y-PSZ crowns produced by subtractive milling.

• 생명과학회지
• /
• 제33권2호
• /
• pp.208-215
• /
• 2023

최근 수십년간 노화연구의 영역은 유전자 수준에서부터 세포 수준을 거쳐 혈액을 교환하는 in vivo 모델까지 진보를 거듭하면서 발전하고 있다. 예쁜꼬마선충에서 수명을 연장시킬 수 있는 유전자의 존재가 알려지면서, 유전체학, 단백질체학, 대사체학, 전사체학과 같은 다양한 분석방법이 사용되면서 보다 다양한 노화 연관 표적분자들이 발견되었다. 따라서, 표적분자들 간의 상호관계에 대한 연구결과도 증가하고 있다. 또한, 두 실험동물을 외과적으로 결합시킨 개체병렬결합 방법을 사용한 노화연구로 노화 현상을 역행시킬 수도 있는 인자가 보고되었고, 젊은 개체의 혈액 내에 존재할 수 있는 노화 역행 인자를 찾기 위한 더 정확하고, 효과적인 연구로 확장되면서, 노화연구의 방법에 새로운 패러다임이 확립되었다. 2022년 실험동물에 정교하게 혈액을 교환할 수 있는 장치에 대한 논문이 발표되었고, 이 장치를 사용한 연구가 노화 역행에 영향을 줄 수 있는 새로운 결과를 제시하였다. 새롭게 고안된 장치와 그로 인한 결과뿐만 아니라 젊은 혈액 또는 조건화된 혈액을 주입하여 얻은 최신 연구결과로 처음 발표되었던 GDF11 외에도 혈액 내에 존재하는 노화 역행 후보물질로서 β2m, TIMP2, VCAM1, Gpld1, clusterin과 같은 혈액 내 용해성 인자뿐만 아니라 mcicroglia 세포와 neuroinflammation과 같은 생화학적 현상이 직접적으로 노화요인으로 증명되고 있다. 이 총설에서는 이 같은 노화연구에 대한 최신 결과에 대해 논의하고자 한다.

• 센서학회지
• /
• 제25권3호
• /
• pp.161-172
• /
• 2016

The use of a chemical sensor array can help discriminate between chemicals when comparing one sample with another. The ability to classify pattern characteristics from relatively small pieces of information has led to growing interest in methods of sensor recognition. A variety of pattern recognition algorithms, including the adaptive radial basis function network (RBFN), may be applicable to gas and/ or odor classification. In this paper, we provide a broad review of approaches for various types of gas and/or odor identification techniques based on RBFN and drift compensation techniques caused by sensor poisoning and aging.

• 한국컴퓨터정보학회논문지
• /
• 제25권1호
• /
• pp.29-36
• /
• 2020

웨어-레벨링과 오류정정코드는 플래시 메모리의 신뢰성과 내구성을 위한 필수적인 기술이다. 플래시 메모리를 구성하는 요소들은 사용횟수에 따른 노화도가 서로 다를 수 있다. 따라서 기존의 쓰기/지우기 횟수를 바탕으로 하는 웨어-레벨링 기술은 요소들의 실제 노화도 차이를 반영하기에 충분하지 않다. 본 논문에서는 높은 오류정정율이 증명된 Low-Dencity Parity-Check (LDPC) 코드를 적용하고 복호 과정에서 나오는 정보를 이용하여 플래시 메모리의 실제 노화도를 측정하는 방법을 소개한다. 실험에서는 실제 플래시 메모리를 대상으로 측정한 오류율 데이터를 기반으로 LDPC 코드 복호 정보가 플래시 메모리 각 블록의 노화도를 나타낼 수 있음을 보인다. 또한, 웨어-레벨링 시뮬레이션을 통하여 제안하는 노화도 측정 방법 기반의 웨어-레벨링의 효과를 입증한다.

• KIEAE Journal
• /
• 제7권1호
• /
• pp.5-13
• /
• 2007

Since aging has become one of most hot and serious issues in the whole global world, universal design as a strategic concept to enable the elderly age in place has received much attention and its importance is getting recognized. Japan has undergone the Aging phenomenon much earlier than Korea and other countries. During that time, through much trials and errors, it accumulated the wisdoms and techniques to precede aging friendly environment and products. Therefore current Japan house is a comprehensive setting which embraces lots of universal design features that has a valuable implication for Korean development that faces fast aging future. The purpose of this study was to delineate characteristics of universal design features appeared in Japanese Model houses. One site of housing park in the city where various model houses of representative housing construction companies was selected as a cluster area for data collecting. Data were collected mainly through field survey at the housing park of Tokyo during November, 2006, and additional data were collected through website and company information of relevant company. Universal design features were extracted for 17 houses of the housing park and sorted and analyzed according to the analysis frame. The frame were made using 2 major clusters; space area, and 8 universal design principle. Results showed a range of universal design feature and its detail universal design principle satisfied. The 8 principle currently developed became to house realistic practical examples and theory became proved its impractical power. The academic, educational and industrial implication were documented.

• Elastomers and Composites
• /
• 제59권2호
• /
• pp.73-81
• /
• 2024

In the field of electronic components, the potting material, which is a part of the electronic circuit package, plays a significant role in protecting circuits from the external environment and reducing signal interference among electronic devices during operation. This significantly affects the reliability of the components. Therefore, the accurate prediction and assessment of the lifespan of a material are of paramount importance in the electronics industry. We conducted an accelerated thermal aging evaluation using the Arrhenius technique on elastic potting material developed in-house, focusing on its insulation, waterproofing, and contraction properties. Through a comprehensive analysis of these properties and their interrelations, we confirmed the primary factors influencing molding material failure, as increased hardness is related to aggregation, adhesion, and post-hardening or thermal-aging-induced contraction. Furthermore, when plotting failure times against temperature, we observed that the hardness, adhesive strength, and water absorption rate were the predominant factors up to 120 ℃. Beyond this temperature, the tensile properties were the primary contributing factors. In contrast, the dielectric constant and loss tangent, which are vital for reducing signal interference in electric devices, exhibited positive changes(decreases) with aging and could be excluded as failure factors. Our findings establish valuable correlations between physical properties and techniques for the accurate prediction of failure time, with broad implications for future product lifespans. This study is particularly advantageous for advancing elastic potting materials to satisfy the stringent requirements of reliable environments.

• 비파괴검사학회지
• /
• 제29권6호
• /
• pp.591-602
• /
• 2009

The Compton backscatter technique has been applied to lap-joint in aircraft structure in order to determine mass loss due to exfoliative corrosion of the aluminum alloy sheet skin. The mass loss of each layer has been estimated from Compton backscatter A-scan including the aluminum sheet, the corrosion layer, and the sealant. A Compton backscattering imaging system has been also developed to obtain a cross-sectional profile of corroded lap-splices of aging aircraft using a specially designed slit-type camera. The camera is to focus on a small scattering volume inside the material from which the backscattered photons are collected by a collimated scintillator detector for interpretation of material characteristics. The cross section of the layered structure is scanned by moving the scattering volume through the thickness direction of the specimen. The theoretical model of the Compton scattering based on Boltzmann transport theory is presented for quantitative characterization of exfoliative corrosion through deconvolution procedure using a nonlinear least-square error minimization method. It produces practical information such as location and width of planar corrosion in layered structures of aircraft, which generally cannot be detected by conventional NDE techniques such as the ultrasonic method.

• 한국주조공학회지
• /
• 제37권1호
• /
• pp.14-20
• /
• 2017

The microstructure, electrical conductivity and hardness variation of an AZ91-5wt%Sn Mg alloy sample during a solid-solution and aging heat treatment were instigated by optical microscopy, scanning electron microscopy, X-ray diffraction and by Rockwell hardness techniques in this study. The XRD result shows that the main phases in the as-casted alloy are ${\alpha}$-Mg, $Mg_{17}Al_{12}$ and $Mg_2Sn$. From the SEM images of the AZ91-5wt%Sn Mg alloy after the solution treatment, the $Mg_{17}Al_{12}$ phases in the alloy were found to have dissolved into the matrix with an increase in the holding time during the solution treatment, but $Mg_2Sn$ phases were clearly observable. The highest peak hardness of the AZ91-5wt%Sn Mg alloy is 82HRE at an aging temperature of $200^{\circ}C$.

• 한국표면공학회지
• /
• 제55권6호
• /
• pp.398-402
• /
• 2022

Vacuum Insulation Panel (VIP) is an high energy efficient insulation system that facilitate slim but high insulation performance, based on based on a porous core material evacuated and encapsulated in a multi-barrier envelope. Although VIP has been on the market for decades now, it wasn't until recently that efforts have been initiated to propose a standard on aging testing. One of the issues regarding VIP is its durability and aging due to pressure and moisture dependent increase of the initial low thermal conductivity with time. It is hard to visually determine at an early stage. Recently, a method of analyzing the damage on the a material surface by applying image processing technology has been widely used. These techniques provide fast and accurate data with a non-destructive way. In this study, the surface VIP images were analyzed using the Harris corner detection algorithm. As a result, 171,333 corner points in the normal packaging were detected, whereas 32,895 of the defective packaging, which were less than the normal packaging. were detected. These results are considered to provide meaningful information for the determination of VIP condition.