• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.1
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• pp.93-97
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• 2022

We report highly efficient quantum dot light-emitting diodes (QLEDs) with TiO₂ nanoparticles (NPs) as an alternative electron transport layer (ETL) and poly (methyl methacrylate) (PMMA) as an insulating layer. TiO₂ NPs were applied as ETLs of inverted structured QLEDs and the effect of the addition of PMMA between ETL and emission layer (EML) on device characteristics was studied in detail. A thin PMMA layer supported to make the charge balance in the EML of QLEDs due to its insulating property, which limits electron injection effectively. Green QLEDs with a PMMA layer produced the maximum luminance of 112,488 cd/m² and a current efficiency of 25.92 cd/A. We expect the extended application of TiO₂ NPs as the electron transport layer in inverted structured QLEDs device in the near future.

• Transactions on Electrical and Electronic Materials
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• v.1 no.3
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• pp.23-28
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• 2000

A block-oxide layer was formed on the surface of Cu-based leadframe by chamical oxidation method in order to enhance the adhesion strength between Cu-based leadframe and epoxy molding compound (EMC) Using sandwiched double cantilever beam (SDCB) specimens, the adesion strength was measured in terms of interfacial fracture toughness, G$\sub$IC//Results showed that the black-oxide layer was composed of two kinds of layers: pebble-like Cu$_2$O layer and acicular CuO layer, At the initial stage of oxidation the Cu$_2$O layer was preferentially formed and thickened up to around 200 nm whithin 1 minute of the oxidation time. Then the CuO layer started to from atop of the Cu$_2$O layer and thickened up to around 1300 nm until 20 minutes. As soon as the CuO layer formed, the thickness of Cu$_2$O layer began to reduce and finally reached to around 150 nm. The pre-cleaned and the Cu$_2$O coated leadframes showed almost no adhesion of EMC, however, as the CuO precipitates appeared and became continuous, G$\sub$IC/ increased up to around 80 J/㎡. Further oxidation raised G$\sub$IC/ up. to around 100 J/㎡.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.939-942
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• 2001

We fabricated Red Organic light-emitting devices(OLED). The Basic Device Structure is ITO/hole transfer layer, TPD(50nm)/red emitting layer, Alq3 doped with DCM2 or DCM2:rubrene(xnm)/electorn transfer layer, Alq3(50-xnm)/LiF(0.8nm)/Al(8nm) . The thickness of emitting layer(xnm) changed 5, 10, 20nm. we demonstrate red emitting OLED with dependent on the thickness and concentrators of Alq3 layer doped with DCM2 or co-doped with DCM2:ruberene. The Emission color and Brightness are changed with doping or co-doping condition, dopant concentarton. In the case of rubrene:DCM2 co-doped layer structure, the red color Purity and device efficiency is improved. The CIE index of rubrene co-doped OLED is x=0.67, y=0.31. By co-doping the Alq3 layer with DCM2, rubrene, EL efficiency improved from 0.38cd/A to 0.44cd/A in comparison whit DCM2 doped Alq3 layer.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.3
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• pp.59-72
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• 2004

In this paper, we classify various attacks that may damage the embedded watermark signal into waveform attack and synchronization attack. And for the specialized defense against the two kinds of attacks we propose a new watermarking scheme named as two layer watermarking method. It consists of a synchronization layer to prepare for the geometrical attack such as rotation and shift and a marking layer 0 embed the watermark signal actually. Namely, the synchronization layer only determines the target region where the watermark signal will be embedded or extracted. And the marking layer spreads the watermark signal over the image as the conventional watermarking methods do. Using the layered structure, the proposed method overcomes the problem that the conventional watermarking methods that do not use the original image at the verification side are most vulnerable to geometrical attacks.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1702-1705
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• 2016

We propose a novel hydrogen-reduced p-type amorphous silicon oxide buffer layer between $TiO_2$ antireflection layer and p-type silicon window layer of silicon thin film solar cells. This new buffer layer can protect underlying the $TiO_2$ by suppressing hydrogen plasma, which could be made by excluding $H_2$ gas introduction during plasma deposition. Amorphous silicon oxide thin film solar cells with employing the new buffer layer exhibited better conversion efficiency (8.10 %) compared with the standard cell (7.88 %) without the buffer layer. This new buffer layer can be processed in the same p-chamber with in-situ mode before depositing main p-type amorphous silicon oxide window layer. Comparing with state-of-the-art buffer layer of AZO/p-nc-SiOx:H, our new buffer layer can be processed with cost-effective, much simple process based on similar device performances.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.2
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• pp.224-233
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• 1991

The multilayer expanson of single layer NN (Neural Network) was needed to solve the linear seperability problem as shown by the classic example using the XOR function. The EBP (Error Back Propagation ) learning rule is often used in multilayer Neural Networks, but it is not without its faults: 1)D.Rimmelhart expanded the Delta Rule but there is a problem in obtaining Ca from the linear combination of the Weight matrix N between the hidden layer and the output layer and H, wich is the result of another linear combination between the input pattern and the Weight matrix M between the input layer and the hidden layer. 2) Even if using the difference between Ca and Da to adjust the values of the Weight matrix N between the hidden layer and the output layer may be valid is correct, but using the same value to adjust the Weight matrixd M between the input layer and the hidden layer is wrong. Recognitron III was proposed to solve these faults. According to simulation results, since Recognitron III does not learn the three layer NN itself, but divides it into several single layer NNs and learns these with learning patterns, the learning time is 32.5 to 72.2 time faster than EBP NN one. The number of patterns learned in a EBP NN with n input and output cells and n+1 hidden cells are 2**n, but n in Recognitron III of the same size. [5] In the case of pattern generalization, however, EBP NN is less than Recognitron III.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.465-467
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• 1998

MPEG-2 는 Layered Coding방식을 채택하여 하나의 base layer와 4개의 enhancement layer로 이루어져 있으나 동영상 재생을 위해 필요한 최소한의 layer인 base layer 만으로도 데이터 양이 많기 때문에 인터넷 환경에 적용하기가 어렵다. 이에 base layer를 다시 세분화된 layer로 나누기 위해 인코딩 중에는 또는 인코딩 결과로 만들어지는 MPEG-2 Video steam 의 하부 구조인 블록층에 존재하는 8$\times$8블록의 AC 계수들을 layering한다. Layered된 base layer의 데이터는 통신망 및 단말기의 QoS에 따라 서로 다른 전송 채널을 통해 서버에서 클라이언트 디코더로 전송된 후 디코더에 실시간적으로 병합한 후 재생된다. 본 논문에서 제안하는 기법을 이용하여 기존에 encoding MPEG-2 Video steam의 AC계수를 layering할 경우에 QoS에 따라 가변적으로 데이터 양을 서버 쪽에서 조절할 수 있었고, 통신 선로 상에서 이동하는 데이터 양의 원래의 MPEG-2 Video steam 을 이용했을 때보다 인코딩 중에 블록을 변환하면 51% 정도 감소하고 인코딩 되어진 데이터를 이용했을 경우에는25%정도 감소하는 것을 알 수 있었다.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.632-635
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• 2004

We have studied the effect of $TiO_2$ layer deposited by RF magnetron sputtering which is used as an ultra thin hole-injection buffer layer in organic light-emitting diode (OLED). The $TiO_2$ thin film layer prevents metallic ions from diffusing from the ITO layer to the organic layers and improves the balance of hole and electron injections and the interface characteristics between the electrode and the organic layer. With 2 nm thickness of $TiO_2$, the quantum efficiency was improved by 45 % compared to the device fabricated without the $TiO_2$ layer.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.1
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• pp.87-95
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• 2002

This study was carried out to investigate the load of soil layers affected by soil depth in artificial soil alone or in blends with Loam with various ratio. The artificial soils were perlite large grain, perlite small grain, and perlite small grains blended with Loam (sand 46%, silt 40%, clay 14%) at a ratio of 8:2, 6:4, 5:5 (v/v). The soil layers were divided into a planting layer and a well-drained layer, then the weight of each layer in the air-dried state and in the field capacity were determined. The data were subjected to correlation analysis, regression analysis, and paired samples t-test. The summarized results are as follows; 1) In the air-dried state, the regression equations of the well-drained layer weight(kg/m2) in perlite large grain, planting layer weight in perlite small grain, planting layer weight in perlite small grain biended with loam(8:2, v/v), perlite small grain blended with loam(6:4, v/v), and perlite small grain blended with loam(5:5, v/v) were; 1.65824*X+0.026, 1.52292*X-0.052, 3.21468*X+0.515, 6.17549*X+ 0.083, and 6.02100*X + 33.133, respectively, where X is soil depth measured in Centimeters. 2) In the field capacity, the regression equations of the well-drained layer weight(kg/m2) in perlite large grain, planting layer weight in perlite small grain, planting layer weight in perlite small grain blended with loam(8:2, v/v), perlite small grain blended with loam(6:4, v/v), and perlite small grain blended with loam(5:5, v/v) were 5.055*X - 2.006, 7.073*X + 100.008, 8.092*X + 116.676, 10.766*X + 100.112, and 10.974*X + 124.423, respectively, where X is the soil depth measured in Centimeters. 3) All of the equations mentioned above were statistically reliable and therefore easily applicable in practical business affairs.

• Journal of Environmental Impact Assessment
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• v.20 no.2
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• pp.151-162
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• 2011

The purpose of this study is suggest to restoration model of Pinus thunbergii in Saha-gu, Busan Metropolitan City. The result of this study is summarized as follows; As the results of this study, vegetation restoration model is presented by separating community planting and edge planting. The community planting species of tree layer were Pinus thunbergii and Quercus acutissima and Quercus dentata and Quercus serrata and Quercus alienna and Quercus variabilis. The community planting species of subtree layer were Platycarya strobilacea and Prunus sargentii and Styrax japonica and Eurya japonica and Morus bombycis. The community planting species of shrub layer are Ulmus pavifolia and Ulmus davidiana and Lindera obtusiloba and Elaeagnus macrophylla and Mallotus japonicus and Ligustrum obtusifolium and Sorbus alnifolia and Rhus trichocarpa and Zanthoxylum schinifolium and Rosa wichuraiana and Rhus chinensis and Viburnum erosum and Rhododendron mucronulatum and Rhododendron yedoense and Indigofera pseudotinctoria. And the planting species of edge vegetation are Japanese Angelica and Symplocos chinensis and Pittosporum tobira and Lespedeza maximowiczii and Lespedeza bicolor and Rubus coreanus and Rubus idaeus and Vitis thunbergii and Ampelopsis brevipedunculata and Rosa multiflora. Considering the population of individuals up to layers in each $400m^2$ area, it was composed of 24 in tree layer, 35 in subtree layer, 410 in shrub layer and 34% herb layer in the Pinus thunbergii community. And the average of breast-high area and canopy area was $10,852cm^2$ in tree layer, in subtree layer $1,546cm^2$, in shrub layer $1,158,660cm^2$. The shortest distance between trees was calculated as 2.0m in tree layer, 1.9m in subtree layer.