• International Journal of Fuzzy Logic and Intelligent Systems
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• v.8 no.4
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• pp.239-247
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• 2008

In a resource-limited wireless communication environment, various approaches to meet the ever growing application requirements in an efficient and transparent manner, are being researched and developed. Amongst many approaches, cross layer technique is by far one of the significant contributions that has undoubtedly revolutionized the way conventional layered architecture is perceived. In this paper, we propose a Universal Cross Layer Framework based on vertical layer architecture. The primary contribution of this paper is the functional architecture of the vertical layer which is primarily responsible for cross layer interaction management and optimization. The second contribution is the use of optimization cycle that comprises awareness parameters collection, mapping, classification and the analysis phases. The third contribution of the paper is the decomposition of the parameters into local and global network perspective for opportunistic optimization. Finally, we have shown through simulations how parameters' variations can represent local and global views of the network and how we can set local and global thresholds to perform opportunistic optimization.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.654-656
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• 2016

MACsec is a cryptographic function that operates on Layer 2. As industries such as IoT(Internet of Things) devices are receiving attention recently are connected to the network and Internet traffic is increasing rapidly. Because of today, Becoming the increase in traffic and complex situations to protect the overall traffic, not just certain parts. The MACsec technology has received attention. In this paper, Layer 2 security technology to MACsec. Design the technology MACsec adapter that can easily and readily added to existing Layer 2 network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.10A
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• pp.1215-1222
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• 2004

In this paper, we proposed the directional coupler using two layer microstrip substrate which is improved coupling and isolation. Modified two-layer directional coupler is the structure which is added to the one-layer on the signal line and located the floating conductor on the added layer. Also, we applied the aperture on the ground plane in order to enhancing the coupling value, and located the conductor in order to enhancing the isolation and VSWR according to S$_{11}$. As a result, proposed two-layer directional coupler has about 2 dB more higher coupling and 20 dB more higher isolation than conventional couplerer

• Journal of Communications and Networks
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• v.18 no.3
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• pp.411-419
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• 2016

This article investigates the problem of distributed channel selection in opportunistic spectrum access networks from a perspective of interference minimization. The traditional physical (PHY)-layer interference model is for information theoretic analysis. When practical multiple access mechanisms are considered, the recently developed binary medium access control (MAC)-layer interference model in the previous work is more useful, in which the experienced interference of a user is defined as the number of competing users. However, the binary model is not accurate in mathematics analysis with poor achievable performance. Therefore, we propose a real-valued one called stochastic MAC-layer interference model, where the utility of a player is defined as a function of the aggregate weight of the stochastic interference of competing neighbors. Then, the distributed channel selection problem in the stochastic MAC-layer interference model is formulated as a weighted stochastic MAC-layer interference minimization game and we proved that the game is an exact potential game which exists one pure strategy Nash equilibrium point at least. By using the proposed stochastic learning-automata based uncoupled algorithm with heterogeneous learning parameter (SLA-H), we can achieve suboptimal convergence averagely and this result can be verified in the simulation. Moreover, the simulated results also prove that the proposed stochastic model can achieve higher throughput performance and faster convergence behavior than the binary one.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.2
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• pp.35-42
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• 2010

In this paper, we propose a ubiquitous Farming Diary System which can support the easy and reliable recording of a farming diary for the certificate on environment-friendly agricultural products by using the USN(Ubiquitous Sensor Network) technologies. By using growth-related data, the system can also control farming facilities remotely and automatically. To achieve this goal, the UFDS(Ubiquitous Farming Diary System) is consisted with 3 layers. The first 'physical layer' can collect data from sensors, cameras and facilities then controls the growth environment based on the analyzed information. The second 'Middle layer' can process and store the data from 'physical layer' to sensor manager, image manager, control manager and diary manager separately. The third 'application layer' can provide growth-related services to users through various applications. The UFDS can recording grow history information automatically and Easily. Besides, the system can make an accurate and reliable farming diary with multimedia information such as motion and sound. Furthermore, environmental information such as temperature, humidity, luminance and soil conditions (soil temperature, soil humidity, soil EC) can be monitored in real-time and the facilities managed in remote sites.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.157-160
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• 2004

본 논문은 미국 차세대 디지털 케이블 방송 표준 규격인 오픈케이블($OpenCable^{TM}$)의 수신제한 모듈인 CableCard의 Physical Layer를 SystemC의 TLM(Transaction Level Modeling)과 RTL(Register-Transfer Level) 모델링 기법으로 설계하였다. 본 논문에서 설계한 CableCard의 Physical Layer는 PCMCIA Interface, Command Inteface 그리고 MPEG-2 TS Interface 로 구성된다. CableCard가 전원이 인가될 때, 카드 초기화를 위하여 동작하는 PCMCIA 인터페이스는 16 비트 PC 카드 SRAM 타입으로 2MByte Memory와 100ns access time으로 동작할 수 있게 설계하였다. PCMCIA 카드 초기화 동작이 완료된 후, CableCard의 기능을 수행하기 위하여 두 개의 논리적 인터페이스가 정의되는데 하나는 MPEG-2 TS 인터페이스이고, 다른 하나는 호스트(셋톱박스)와 모듈 사이의 명령어들을 전달하는 명령어 인터페이스(Command Interface)이다. 명령어 인터페이스(Command Interface)는 셋톱박스의 CPU와 통신하기 위한 1KByte의 Data Channel과 OOB(Out-Of-Band) 통신을 위한 4KByte의 Extended Channel 로 구성되고, 최대 20Mbits/s까지 동작한다. 그리고 MPEG-2 TS는 100Mbits/s까지 동작을 수행할 수 있게 설계하였다. 설계한 코드를 실행한 후, Cadence사의 SimVision을 통해서 타이밍 시뮬레이션을 검증하였다.

• Journal of Information Display
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• v.6 no.3
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• pp.26-29
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• 2005

Nanosize cobalt aluminate($CoAl_2O_4$) power was coated as filter layer for us to improve the color purity and contrast performances on the inner face of CRT panel. We simulated color properties by measuring the transmittance and thickness of the coated filter layer. Contrast performance could be improved and color gamut was also changed by the selective light absorption of filter layer at 580${\sim}$605 nm.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1519-1521
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• 2007

In this work, a coplanar-type plasma flat fluorescent lamp having cross type of electrode was fabricated by screen printing and sealing technique. Cross type of electrode with a dielectric layer were screen-printed on a rear glass plate, and then fired at $550^{\circ}C$. Phosphor was printed on and fired at $450^{\circ}C$. Finally, the lamp was sealed by frit glass at $450^{\circ}C$. The lamp of cross electrode type was studied depending on the electrode gap and the thickness of dielectric layer.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.151-152
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• 2005

Blu-ray 디스크에서는 NA=0.85 의 높은 개구수를 채용함으로써 디스크 보호층의 두께 변동에 따른 구면수차 발생량이 매우 커지는 문제가 발생하게 된다. 따라서 디스크 두께 공차 $3{\mu}m$에서 Blu-ray 시스템의 수차 발생 허용수준을 초과한다. 그리고 Multi-layer 디스크의 경우 각 층의 간격이 $25{\mu}m$ 정도의 간격을 두고 배치되어 있어 기록층 사이에서 발생하는 구면수차의 보정이 필요하며, 종래의 기술은 보상범위가 $3{\mu}m$로 한정되어 사용이 불가능하며 또한 대물렌즈 조립공차가 엄격히 관리되어야 하는 문제점을 안고 있었다. 본 연구에서는 액정렌즈에 의한 구면수차 보정으로 이러한 문제점들을 해결하고자 하였다. 액정렌즈는 오목렌즈 액정소자와 볼록렌즈 액정소자로 구성되며 픽업 광학계 내에 조합하여 설계함으로써 Multi-layer 디스크의 두께 변동에 따라 발생하는 구면수차를 보정하고 대물렌즈 조립공차 문제를 해결할 수 있다.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.42-45
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• 2009

We report simple structure red phosphorescent devices comprising only single organic layer structure. Maximum current efficiency of 9.44 cd/A and the driving voltage of 5.4 V are obtained in this single layer structure PHOLEDs, respectively. The mixed host system using electron transporting and hole transporting materials doped with $Ir(piq)_3$ provides such high efficiency and reasonable driving voltage. The principal to simplification is the direct charges injection from the metallic electrodes into mixed host materials.