• Applied Science and Convergence Technology
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• v.23 no.5
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• pp.289-295
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• 2014

${\alpha}-V_2O_5$ nanorods were grown by means of electron beam irradiation and thermal oxidation methods and the visible emission properties of the nanorods grown by both methods were investigated. The growth and crystallinity of the nanorods were greatly enhanced by the insertion of a buffer layer. The emission spectra of the nanorods grown by thermal oxidation and electron beam irradiation showed a peak centered at 710~720 nm, which is believed to be due to oxygen vacancies introduced during the growth process. Also, the emission peak centered at 530 nm observed in the $V_2O_5$ nanorods grown by electron beam irradiation was considered to be due to the band edge transition as a result of the enhanced crystallinity.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.8
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• pp.406-413
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• 2001

본 논문은 CMOS 디지털 회로에서 글리치(glitch)에 의해 발생하는 전력소모를 줄이기 위한 효율적인 휴리스틱 알고리즘을 제시한다. 제안된 알고리즘은 사이징되는 게이트의 위치와 양에 따라 게이트 사이징을 세 가지 type으로 분류한다. 또한 버퍼삽입은 삽입되는 버퍼의 위치에 따라서 두 가지 type으로 분류한다. 글리치 제거 효과를 극대화하기 위해서 비용과 이득의 상관관계를 고려하여 하나의 최적화 과정 안에서 세 가지 type의 게이트 사이징과 두 가지 type의 버퍼삽입을 혼합한다. 제안된 알고리즘은 0.5$\mu\textrm{m}$ 표준 셀 라이브러리(standard cell library)를 이용한 LGSynth91 벤치마크 회로에 대한 테스트 결과 효율성을 검증하였다. 실험결과는 평균적으로 69.98%의 글리치 감소와 28.69%의 전력감소를 얻을 수 있었으며 이것은 독립적으로 적용된 게이트 사이징과 버퍼 삽입 알고리즘에 의한 것 보다 좋은 결과이다.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.5
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• pp.555-562
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• 1999

VLSI 시스템 설계 단게에서 시스템의 고성능 및 고신뢰성을 보장하는 것이 중용한 요건이 되고 있다. 본 논문은 회로의 긴 경로들과 짧은 경로들 상에 존재하는 구성요소들간의 시간지연들이 타이밍 제약조건들을 만족하도록 최적화시킴으로서 고성능 및 고신뢰도를 동시에 실현할 수 있는 효율적인 알고리즘을 제안한다. 과거에는 VLSI 시스템의 고성능을 실현하기 위한 긴 경로 최적화와 고신뢰도를 실현하기 위한 짧은 경로 최적화를 각각 독립적으로 수행하는 방법들이 제안되었다. 본 논문은 긴 경로들 및 짧은 경로들 상의 시간지연 요소들을 동시에 최적화함으로써 적절한 수행시간과 적은 메모리 요구량의 오버헤드를 허용하는 범위에서 효과적인 단계들로 수행되는 병합 알고리즘을 제안하고자한다. 그리고 제안된 병합 알고리즘의 효율성을 입증하기 위해 벤치마크 회로들을 이용하여 실험 결과들을 보여줄 것이다.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05c
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• pp.431-436
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• 2002

네트워크를 통한 미디어 서비스에 있어 다양한 미디어 서비스의 개발과 사용자들의 요구에 대응하기 위해 사용자와의 상호대화를 할 수 있는 미디어 전달 방법과 연속적인 재생을 보장하기 위한 버퍼정책이 요구된다. 지금까지의 관련된 연구에서는 여러 가지 다양한 방법을 통하여 동기화를 달성하고 있으나 상호대화라는 측면에서는 만족할 만한 해결책을 제시하지 않고 있다. 본 논문에서는 상호대화형 객체(Interactive Object)를 각 미디어 파일에 삽입하고 객체들이 서로의 정보를 이용할 수 있는 함수를 설계하여 동기화와 상호대화성이라는 문제를 해결하며 네트워크에 대한 의존성 때문에 발생하는 불연속적인 재생을 가변 버퍼를 이용함으로써 해결하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.8
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• pp.1828-1834
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• 2004

With the rapid development of wireless communications and mobile technologies, requirements of various services based on moving objects like location-based services and mobile applications services have been increased. In this paper, we propose an index structure which can improve the performance on trajectory-based query especially, one of the various query types for moving objects in mobile applications. It maintains link table(L-Table) to obtain good efficiency on retrieval and insertion performance of the existing TB(Trajectory Bundle)-tree proposed for trajectory-based query of moving objects. The L-Table contains page number in disk and memory pointers pointing the leaf node with the first and last line segment of moving objects in order to directly access preceding node. In addition, we design to reside a part of whole index in main memory by preserving a fixed size of buffer in case of being restricted by available main memory. Finally, experimental results with various data sets show that the proposed technique is superior to the existing index structures with respect to insertion and trajectory-based query.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.4
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• pp.1-14
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• 2004

In this study, we propose Linktable based on extended TB-Tree(LTB-Tree) which can improve the performance of existing TB (Trajectory-Bundle)-tree proposed for indexing the trajectory of moving objects in GIS Applications. In addition, in order to evaluate proposed indexing scheme, we take into account as follows. At first, we select existing R*-tree, TB-tree, and LTB-tree as the subject of performance evaluation. Secondly, we make use of random data set and real data set as experimental data. Thirdly, we evaluate the performance with respect to the variation of size of memory buffer by considering the restriction of available memory of a given system. Fourth, we test them by using the experimental data set with a variation of data distribution. Finally, we think over insertion and retrieval performance of trajectory query and range query as experimental measures. The experimental results show that the proposed indexing scheme, LTB-tree, gains better performance than traditional other schemes with respect to the insertion and retrieval of trajectory query.

• Journal of the Optical Society of Korea
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• v.13 no.1
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• pp.65-74
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• 2009

Device quality indium tin oxide (ITO) films are deposited on glass substrates and ultra-thin diamond-like carbon films are deposited as a buffer layer on ITO by a pulsed Nd:YAG laser at 355 nm and 532 nm wavelength. ITO films deposited at room temperature are largely amorphous although their optical transmittances in the visible range are > 90%. The resistivity of their amorphous ITO films is too high to enable an efficient organic light-emitting device (OLED), in contrast to that deposited by a KrF laser. Substrate heating at $200^{\circ}C$ with laser wavelength of 355 nm, the ITO film resistivity decreases by almost an order of magnitude to $2{\times}10^{-4}\;{\Omega}\;cm$ while its optical transmittance is maintained at > 90%. The thermally induced crystallization of ITO has a preferred <111> directional orientation texture which largely accounts for the lowering of film resistivity. The background gas and deposition distance, that between the ITO target and the glass substrate, influence the thin-film microstructures. The optical and electrical properties are compared to published results using other nanosecond lasers and other fluence, as well as the use of ultra fast lasers. Molecularly doped, single-layer OLEDs of ITO/(PVK+TPD+$Alq_3$)/Al which are fabricated using pulsed-laser deposited ITO samples are compared to those fabricated using the commercial ITO. Effects such as surface texture and roughness of ITO and the insertion of DLC as a buffer layer into ITO/DLC/(PVK+TPD+$Alq_3$)/Al devices are investigated. The effects of DLC-on-ITO on OLED improvement such as better turn-on voltage and brightness are explained by a possible reduction of energy barrier to the hole injection from ITO into the light-emitting layer.

• Journal of Digital Contents Society
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• v.13 no.1
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• pp.37-41
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• 2012

In this paper, we proposed FPGA algorithm for consider the power consumption. Proposed algorithm generated a feasible cluster by circuit partition considering the CLB condition within FPGA. Separated the feasible cluster reduced power consumption using glitch removal method. Glitch removal appled delay buffer insertion method by signal process within the feasible cluster. Also, removal glitch between the feasible clusters by signal process for circuit. The experiments results show reduction in the power consumption by 7.14% comparing with that of [9].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.13-16
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• 2009

In this study, AlN thin films were deposited on a polycrystalline (poly) 3C-SiC buffer layer for surface acoustic wave (SAW) applications using a pulsed reactive magnetron sputtering system. AFM, XRD and FT-IR were used to analyze structural properties and preferred orientation of the AlN/3C-SiC thin film. Suitability of the film in SAW applications was investigated by comparing the SAW characteristics of an interdigital transducer (IDT)/AlN/3C-SiC structure with the IDT/AIN/Si structure at 160 MHz in the temperature range $30-150^{\circ}C$. These experimental results showed that AlN films on the poly 3C-SiC layer were highly (002) oriented. Furthermore, the film showed improved temperature stability for the SAW device, $TCF\;=\;-18\;ppm//^{\circ}C$. The change in resonance frequency according to temperature was nearly linear. The insertion loss decrease was about $0.033dB/^{\circ}C$. However, some defects existed in the film, which caused a slight reduction in SAW velocity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.318-319
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• 2008

In this article, magnetic properties of multiferroic bi-layer $BiFeO_3$ (BFO)/$BaTiO_3$ (BTO) thin films were studied. It was found that the magnetization increased by the insertion of BTO buffer layer even though the interfacial stress was slightly relaxed, which indicated a coupling between the ferroelectric and ferromagnetic orders. Furthermore, with slightly increase of BFO film thickness, both BFO and BFO/BTO bi-layer films showed anisotropic magnetic properties with higher in-plane magnetization than the values measured out-of-plane. These are attributable to strain constraint effect at the interface.