• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.190-196
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• 1999

Hot forgeability of STD 61 steel was boronzed in boronizing paste mainly consisted of B4C and Na2B4O7 at various temperatures and times. Microhardness and thickness of boride layers were measured and distributions of B, Si, Cr and V on the cross section of specimen were observed by EPMA line analysis. Microscopic examination and results of EPMA showed that the boride layer consisted of two layers outer layer of FeB and inner layer of Fe2B. Microhardness of these boride layers was in the range of Hv 1800~2300. Thickness of boride layer increased with times and temperatures. Si-rich $\alpha$ layer was formed between boride layer and matrix. Element such as Cr concentration as Cr23(B, C)6 beneath the boride layer.

• 반도체디스플레이기술학회지
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• 제5권1호
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• pp.39-43
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• 2006

The polyvinyl series organic films as gate insulators of thin film transistor(TFT) have been processed and characterized on the polyether sulphone (PES) substrates . The poly-4-vinyl phenol(PVP) and polyvinyl toluene (PVT) were used as solutes and propylene glycol monomethyl ether acetate(PGMEA) as a solvent in the formation of organic insulators. The cross-linking of organic insulators was also attempted by adding the thermosetting material, poly (melamine-co-formaldehyde) as a hardener in the compound. The electrical characteristics measured in the metal-insulator-metal (MIM) structures showed that insulating properties of PVP layers were generally superior to those of PVT layers. Among the layers of PVP series; copolymer PVP(10 wt%), 5wt% cross-linked PVP(10 wt%), copolymer PVP(20 wt%), 5 wt% cross-linked PVP(20 wt%) and 10 wt% cross-linked PVP(20 wt%), the 10 wt% cross-linked PVP(20 wt%) layer showed the lowest leakage current of 1.2 pA at ${\pm}10V$. The ms value of surface roughness and the capcitance per unit area are 2.41 and $1.76nF/cm^2$ in the case of 10 wt% cross-linked PVP(20 wt%) layer, respectively.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.61-64
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• 2008

The present study of these experiments are close examination of spray characteristics that are continuous liquid jet and modulated pressure pulse liquid jet. The experiments were conducted using water, over a range of cross-flow velocities from 42${\sim}$136 m/s, with injection frequencies of 35.7${\sim}$166.2 Hz. Between continuous cross-flow jet and pressure pulsed cross-flow jet for characteristics of penetration, breakup point, spray angle and macro spray shape are investigated experimentally. In cross-flow field, main parameter of liquid jet for breakup was cross-flow stream rather than pressure pulse frequency. As oscillation of the periodic pressure that could make liquid jet moved up and down, the mixing efficiency was increased. Also, a bulk of liquid jet puff was detected at upper field of liquid surface. So, this phenomenon has a good advantage of mixing spray from concentration of center area to outer area. Because of pressure pulsation frequency, an inclination of SMD for the structured layer was evanescent. Cross-sectional characteristics of SMD at downstream area were non-structured distributions. Then cross-sectional characteristics of SMD size were about same tendency over a range that is effect of spray mixing. The tendency of volume flux value for various frequency of pressure pulse was same distribution. And volume flux was decreased when the frequency of pressure pulse increase.

• 한국음향학회지
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• 제39권5호
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• pp.497-504
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• 2020

화자 검증에서 화자 임베딩 구축은 중요한 이슈이다. 일반적으로, 화자 임베딩 인코딩을 위해 자기주의 메커니즘이 적용되어졌다. 이전의 연구는 마지막 풀링 계층과 같은 높은 수준의 계층에서 자기 주의를 학습시키는 데 중점을 두었다. 이 경우, 화자 임베딩 인코딩 시 낮은 수준의 계층의 영향이 감소한다는 단점이 있다. 본 연구에서는 잔차 네트워크를 사용하여 Masked Cross Self-Attentive Encoding(MCSAE)를 제안한다. 이는 높은 수준 및 낮은 수준 계층의 특징 학습에 중점을 둔다. 다중 계층 집합을 기반으로 각 잔차 계층의 출력 특징들이 MCSAE에 사용된다. MCSAE에서 교차 자기 주의 모듈에 의해 각 입력 특징의 상호 의존성이 학습된다. 또한 랜덤 마스킹 정규화 모듈은 오버 피팅 문제를 방지하기 위해 적용된다. MCSAE는 화자 정보를 나타내는 프레임의 가중치를 향상시킨다. 그런 다음 출력 특징들이 합쳐져 화자 임베딩으로 인코딩된다. 따라서 MCSAE를 사용하여 보다 유용한 화자 임베딩이 인코딩된다. 실험 결과, VoxCeleb1 평가 데이터 세트를 사용하여 2.63 %의 동일 오류율를 보였다. 이는 이전의 자기 주의 인코딩 및 다른 최신 방법들과 비교하여 성능이 향상되었다.

• 한국해양바이오학회지
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• 제6권2호
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• pp.53-61
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• 2014

This study was investigated the antimicrobial activity of glutaraldehyde cross-linked glucosamine. Glutaraldehyde was used as a cross-linker which specifically combines an amine-group of molecules. To optimize the mixing ratio of glutaraldehyde and glucosamine, mixing ratio was set up 1:1, 2:1, 3:1 and 0.5:1 in molarity, respectively. The optimum mixing ratio of glucosamine and glutaraldehyde was found to be 3:1 using thin layer chromatography based on the production of complex. Glucosamine-glutaraldehyde cross-linked complex (Ggcc) revealed significant antimicrobial activity toward PWG than F1, both microbial strains were isolated from porcine semen as antibiotics resistance bacteria (ARB). These results clearly demonstrate that Ggcc has potential bactericidal activity toward ARB in porcine semen.

• 한국멀티미디어학회논문지
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• 제25권6호
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• pp.819-832
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• 2022

Cross-domain recommender system transfers knowledge across different domains to improve the recommendation performance in a target domain that has a relatively sparse model. However, they suffer from the "negative transfer" in which transferred knowledge operates as noise. This paper proposes a novel Multiple Fusion-based Deep Cross-Domain Recommendation named MFDCR. We exploit Doc2Vec, one of the famous word embedding techniques, to fuse data user-wise and transfer knowledge across multi-domains. It alleviates the "negative transfer" problem. Additionally, we introduce a simple multi-layer perception to learn the user-item interactions and predict the possibility of preferring items by users. Extensive experiments with three domain datasets from one of the most famous services Amazon demonstrate that MFDCR outperforms recent single and cross-domain recommendation algorithms. Furthermore, experimental results show that MFDCR can address the problem of "negative transfer" and improve recommendation performance for multiple domains simultaneously. In addition, we show that our approach is efficient in extending toward more domains.

• ETRI Journal
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• 제27권4호
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• pp.377-384
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• 2005

We investigate near-infrared light (NIR) propagation in a model of an adult head using an extensive Monte Carlo (MC) simulation. The adult head model is a four-layered slab which consists of a surface layer, a cerebrospinal fluid layer, a gray-matter layer, and a white-matter layer. We study the effects of a refractive index mismatch on the model, calculating the intensity of detected light, mean flight time, and partial mean flight time of each layer for various refractive indices of the cerebrospinal fluid layer as functions of source-detector spacing. The Monte Carlo simulation shows that the refractive index mismatch presents very rich results including rapidly decaying intensity of detected light and a peak and cross-over in the partial mean flight time with source-detector spacing. We also investigate spatial sensitivity profiles at various source-detector spacings, discussing the index mismatch effect on the model.

• 한국유체기계학회 논문집
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• 제12권2호
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• pp.8-16
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• 2009

The objective of this study is to investigate the three-dimensional turbulence flow characteristics of a rotor passage of an one-stage axial flow gas turbine and to investigate the effects of a boundary layer fence installed on the hub endwall of the rotor passage. Secondary flows occurring within the rotor passage (e.g. horseshoe vortex, passage vortex, and cross flow) cause secondary loss and reduce turbine efficiency. To control these secondary flows, a boundary layer fence measuring half the height of the thickness of the inlet boundary layer was installed on the hub endwall of the rotor passage. This study was performed numerically. The results show that the wake and secondary flows generated by the stator reduced the rotor load to constrain the development of cross flow and secondary flow reinforced by the rotor passage. In addition, the secondary vortices occurring within the rotor passage were reduced by the rotation of the rotor. Although, the boundary layer fence induced additional vortices, giving rise to an additional loss of turbine, its presence was shown to reduce the total pressure loss when compared to effects of the case without fence regardless of the relative position of blades by enervating secondary vortices occurred within the rotor passage.

• Restorative Dentistry and Endodontics
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• 제28권6호
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• pp.491-497
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• 2003

The purpose of this study was to evaluate the correlation between hybrid layer thickness and bond strength using confocal laser scanning microscope and microtensile bond strength test of two adhesive systems. The dentin surface of human molars. sectioned to remove the enamel from the occlusal surface. Either Scotchbond Multi-Purpose(3M Dental Product, St. Paul, MN, U.S.A) or Clearfil SE Bond (Kuraray, Osaka, Japan) was bonded to the surface. and covered with resin-composite. The resin-bonded teeth were serially sliced perpendicular to the adhesive interface to measure the hybrid layer thickness by confocal laser scanning microscope. The specimen were trimmed to give a bonded cross-sectional surface area of $1\textrm{mm}^2$, then the micro-tensile bone test was performed at a cross head speed of 1.0 mm/min. All fractured surfaces were also observed by stereomicroscope. There was no significant differences in bond strengths the materials(p>0.05). However. the hybrid layers of three-step dentin adhesive system, SM, had significantly thicker than self-etching adhesive system. CS(p<0.05). Pearson's correlation coefficient showed no correlation between hybrid layer thickness and bond strengths(p>0.05). Bond strengths of dentin adhesive systems were not dependent on the thickness of hybrid layer.

• 한국기계가공학회지
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• 제18권3호
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• pp.66-73
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• 2019

Recently, FDM-type 3D printer technology has been developed, and efforts have been made to improve the output formability and characteristics further. Through this, 3D printers are used in various fields, and printer technologies are suggested according to usage, such as FDM, SLA, DLP, and SLM. In particular, the FDM method is the most widely used, and the FDM method technology is being developed further. The characteristics of the output are produced by the FDM-type 3D printer, which is determined by various factors, and particularly the perspective of the Inter-Layer Fill Factor, which is the volume ratio of the laminated material that exerts a direct influence. In this study, the Inter-Layer Fill Factor is theoretically obtained by presenting the internal space between each layer according to the laminate thickness as a cross-sectional shape model, and the cross section of the actual laminated sample is compared with the theoretical model through experiments. Then, the equation for the theoretical model is defined, and the strength change according to each condition (tensile strength of material, reduction slope, strength reduction rate, and output strength) is confirmed. In addition, we investigated the influence on the correlation and strength between laminate thickness and the Inter-Layer Fill Factor.