• Polymer(Korea)
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• v.36 no.4
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• pp.519-524
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• 2012

Capacitance measurements of the polymer light-emitting diodes (PLEDs) with conjugated polyelectrolyte (CPE) electron transporting layers (ETLs) provide important information of device physics for understanding the function of CPEs as ETLs, together with current density-voltage-luminescence measurements. We investigated the counterion-dependent capacitance behaviors that present a highly negative or positive capacitance at the low frequency, and suggested different carrier injection mechanisms. Capacitance model study reveals that the electron injection mechanism can be described either by the dipole alignment scheme or by electronic charge carrier accumulation at the cathode/ETL/emission layer interfaces.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.4
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• pp.25-37
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• 2009

This Study constructs a dashboard system to synthetically and systematically monitor national R&D information based on data warehouse. Managing the national R&D statistics and trend is important since it provides data for policies and decision making for national R&D. Many agencies related to national R&D information collect the basic R&D statistic data which provides the basis of logical decision making and R&D policies. The data has not well been used. The data has not been consistently collected nor managed. The raw data has not been organized nor processed to meet various demands. The needs has been arisen for a consistent national R&D monitoring system to increase the relevance, accessibility and efficiency of data for various users. This study selects 25 key indicators based on the user requirements and designs data warehouse for supporting the indicators using star schema. The dashboard system is developed in this study provides the infrastructure of monitoring national R&D information and analytic environment of supporting statistical analysis and time-series data analysis.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.1
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• pp.19-22
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• 2003

The co-evaporated cathodes composed of A1 and CsF is adopted to enhance the electrical and the optical properties of organic light emitting diodes (OLEDs). The hole transport layer (HTL), made of 50nm thick N,N-dipheny1-N,N-bis(3-methylphenyl)-1,1-bipheny14,4-diamine (TPD), and the electron transport layer (ETL), made of 50nm thick tris(8-hydroxy-quinoline) aluminum (A1q$_3$), were deposited under the base pressure of 1.6$\times$10$^{-6}$ Torr. In depositing A1-CsF, the mass ratio of CsF is varied between 1 and 10wt%. OLEDs with co-evaporated cathodes have luminance of about 35,000cd/$m^2$, and external quantum efficiency of about 1.38%. Cs tends to diffuse into the organic layer and then re-forms Cs$^{+}$cation and free electron with the Cs-doped surface region.n.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.1
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• pp.30-33
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• 2006

Transparent indium tin oxide (ITO) anode surface was modified using $O_3$ Plasma and organic ultrathin buffer layers were deposited on the ITO surface using 13.56 MHz RF plasma polymerization technique. The EL efficiency, operating voltage and lifetime of the organic light-emitting device (OLED) were investigated in order to study the effect of the plasma surface treatment and role of plasma polymerized organic ultrathin buffer layer. Poly methylmethacrylate (PMMA) layers were plasma polymerized on the ITO anode as buffer layer between anode and hole transport layer (HTL). The plasma polymerization of the organic ultrathin layer were carried out at a homemade capacitive-coupled RF plasma equipment. N,N'-diphenyl-N,N'(3- methylphenyl)-1,1'-diphenyl-4,4'-diamine (TPD) as HTL, Tris(8-hydroxyquinolinato) Aluminum $(Alq_3)$ as both emitting layer (EML)/electron transport layer (ETL), and aluminum layer as cathode were deposited using thermal evaporation technique. Effects of the plasma surface treatment of ITO and plasma polymerized buffer layers on the OLED performance were discussed.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1412-1413
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• 2006

In this research, an organic thin 13 passivation layer was newly adopted to prefect the organic layer from ambient moisture and oxygen. As the organic thin film passivation layer, poly methyl methacrylate thin films (ppMMA) were deposited using a plasma polymerization technique. In order to their passivation performance for OLEDs, water vapor transmission rate (WVTR) of the ppMMAs were analyzed and luminance-current-voltage (L-I-V)/luminance-time (L-T) characteristics of the OLEDs with and without ppMMA passivation layer were investigated. The OLEDs had a structure of ITO/TPD (HTL)/Alq3(EML&ETL)/Al. The OLED with ppMMA passivation layer showed improved L-T performance than that of without ppMMA passivation layer.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1359-1360
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• 2006

lTO(Indium-Tin-Oxide) was used as anode material for OLED. Characteristics of ITO have great effect on efficiency of OLEDS(Organic light emitting diodes). ITO surface was treated by Nd:YAG laser in order to improve its chemical properties, wettability, adhesive property and to remove the surface contaminants while maintaining its original function. In this study, main purpose was to improve the efficiency of OLEDs by the ITO surface treatment: ITO surface was treated using a Nd:YAG(${\lambda}=266nm$, pulse) with a fixed power of 0.06[w] and various stage scanning velocities. Surface morphology of the ITO was investigated by AFM. Test OLEDs with surface treated ITO were fabricated by deposition of TPD (HTL), Ald3 (ETL/TML) and Al (cathode) thin films. Device performance of the OLEDs such as V-I-L was investigated using Source Measurement Unit (SMU: Keithly. Model 2400) and Luminance Measurement (TOPCON. BM-8).

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2726-2728
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• 2001

This paper describes an optimal synthesis method of binary neural network(BNN) for an approximation problem of a circular region using a newly proposed learning algorithm[7] Our object is to minimize the number of connections and neurons in hidden layer by using a Newly Expanded and Truncated Learning Algorithm(NETLA) for the multilayer BNN. The synthesis method in the NETLA is based on the extension principle of Expanded and Truncated Learning(ETL) and is based on Expanded Sum of Product (ESP) as one of the boolean expression techniques. And it has an ability to optimize the given BNN in the binary space without any iterative training as the conventional Error Back Propagation(EBP) algorithm[6] If all the true and false patterns are only given, the connection weights and the threshold values can be immediately determined by an optimal synthesis method of the NETLA without any tedious learning. Futhermore, the number of the required neurons in hidden layer can be reduced and the fast learning of BNN can be realized. The superiority of this NETLA to other algorithms was proved by the approximation problem of one circular region.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.177-180
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• 2004

발광층에 Alq3와 rubrene을 mixed host로 사용하고 DCJTB를 형광 dopant로 사용한 다층 박막 구조의 red OLEDs를 제작하였다. 소자의 구조는 $ITO:Anode(120nm)/{\alpha}-NPD:HTL(40nm)/Alq_3+Rubrene(mixed\;host\;1:1)+DCJTB(red\;dopant\;3%)+:EML(20nm)/Alq_3:ETL(40nm)/MgAg(Mg\;5%\;wt):Cathode(150nm)$ 로서 EML내부에 DCJTB를 Totally Doping Method와 Dotted-Line Doping Method의 두 가지 방법으로 도핑 하였다. Mixed host구조에 DCJTB를 6구간으로 나누어 Dotted Line Doping한 소자는 luminance yield가 $9.2cd/A@10mA/cm^2$ 이었다. 이 소자는 DCJTB만을 Totally Doping한 소자의 luminance yield $3.2cd/A@10mA/cm^2$에 비해 약 190%정도의 높은 효율 향상을 보였다. 또한 $10mA/cm^2$에 도달하는 전압은 5.5V Vs. 8.5V로서 mixed host를 사용한 소자에서 약 3V정도 구동전압이 낮아지는 효과가 있었다. 발광 스펙트럼의 Full Width Half Maximum(FWHM)은 각각 56.6nm와 61nm로서 rubrene을 mixed host로 사용한 소자에서 높은 색 순도를 얻을 수 있었다. 이러한 성능의 향상은 $Alq_3$와 혼합된 rubrene에 의한 낮은 전하주 입장벽, 높은 전류밀도에서 나타나는 발광감쇄현상의 감소, 그리고 발광층의 DLD구조에 의한 전하의 trap & confinement 에 따른 발광 exciton의 형성확률이 증가한데서 나타났다고 생각된다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.08a
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• pp.41-46
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• 2002

본 논문은 냉, 난방 디지털 온도 조절계(SPC 50)의 Etl의 편차 정 동작에 관한 구현장치 제작과 비례 미.적분기가 At 및 비 At기능에서 설정온도를 $100^{\circ}C$를 유지하는데 기인된 전압전류 및 전력데이터 획득의 요인과 비례미적분 정수 및 노 개선점을 연구하였다. 설정온도를 유지하는 온도변화는 At기능에서 $96.7^{\circ}C\sim102^{\circ}C$ 이며, 비At 기능에서는 $97.6^{\circ}C\sim100.2^{\circ}C$이었다. 온도유지 전압변동은 At기능에서 2V~217V이며, 비 At기능에서 20V~217V 이었다. At와 비 At 기능에서 설정온도 $100^{\circ}C$을 유지하는데 온도를 냉각시키는 환풍기가 온. 오프 되는 시간차는 20초 정도 발생하였다. 온도차 및 전압차는 두 기능간에 비례 미. 적분값 설정이 자동 및 수동이냐에 따라서 차이를 보여주었다. 두 기능에서 설정된 온도값 유지에 따른 전압전류의 승압과 하강의 변동된 변환 데이터는 설정된 온도가 성취되어지는 시간차 및 설정값 유지의 특성을 요인으로 한 PID값과 노의 개선점에 길잡이가 된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.84-97
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• 2012

M2M (Machine-to-Machine) Technology makes it possible to network all kinds of terminal devices and their corresponding enterprise applications. Therefore, several M2M platforms were developed in China in order to collect information from terminal devices dispersed all over the local places through 3G wireless network. However, when enterprise applications try to integrate with M2M platforms, they should be maintained and refactored to adapt the heterogeneous features and properties of M2M platforms. Moreover, syntactical and semantic unification for information sharing among applications and devices are still unsolved because of raw data transmission and the usage of distinguished business vocabularies. In this paper, we propose and develop an M2M Middleware to support agile application integration with M2M platform. This middleware imports the event engine and XML-based syntax to handle the syntactical unification, makes use of Ontology-based semantic mapping to solve the semantic unification and adopts WebService and ETL techniques to sustain multi-pattern interactive approach, in order to agilely make applications integrated with the M2M platform. Now, the M2M Middleware has been applied in the China Telecom M2M platform. The operation results show that applications will cost less time and workload when being integrated with M2M platform.