• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.206.2-206.2
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• 2015

최근 비정질 산화물 반도체 thin film transistor(TFT)는 차세대 투명 디스플레이로 많은 관심을 받고 있으며 활발한 연구가 진행되고 있다. 산화물 반도체 TFT는 기존의 비정질 실리콘 반도체에 비하여 큰 on/off 전류비, 높은 이동도 그리고 낮은 구동전압으로 인하여 차세대 투명 디스플레이 산업에 적용 가능하다는 장점이 있다. 한편 기존의 sputter나 evaporator를 이용한 증착 방식은 우수한 막의 특성에도 불구하고 많은 시간과 제작비용이 든다는 단점을 가지고 있다. 따라서 본 연구에서는 별도의 고진공 시스템이 필요하지 않을 뿐만 아니라 대면적화에도 유리한 용액공정 방식을 이용하여 박막 트렌지스터를 제작하였으며 thermal 열처리와 microwave 열처리 방식에 따른 전기적 특성을 비교 및 분석하고 각 열처리 방식의 열처리 온도 및 조건을 최적화 하였다. 제작된 박막 트렌지스터는 p-type bulk silicon 위에 산화막이 100 nm 형성된 기판에 spin coater을 이용하여 Al-Zn-Sn-O 박막을 형성하였다. 연속해서 photolithography 공정과 BOE (30:1) 습식 식각 과정을 이용해 활성화 영역을 형성하여 소자를 제작하였다. 제작 된 소자는 Pseudo-MOS FET구조이며, 프로브 탐침을 증착 된 채널층 표면에 직접 접촉시켜 소스와 드레인 역할을 대체하여 동작시킬 수 있어 전기적 특성평가가 용이하다는 장점을 가지고 있다. 그 결과, microwave를 통해 열처리한 소자는 100oC 이하의 낮은 열처리 온도에도 불구하고 furnace를 이용하여 열처리한 소자와 비교하여 subthreshold swing(SS), Ion/off ratio, field-effectmobility 등이 개선되는 것을 확인하였다. 따라서, microwave 열처리 공정은 향후 저온 공정을 요구하는 MOSFET 제작 시의 훌륭한 대안으로 사용 될 것으로 기대된다.

• TTA Journal
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• s.126
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• pp.24-29
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• 2009

IT조선 융합의 목적은 조선산업에 IT기술을 접목해 조선산업의 초인류화를 달성하여 향후 5~10년 후에도 조선강국을 유지하고자 하는 데 있습니다. 이를 위해 정부에서는 제품의 고기능화 및 제조업의 고부가가치화를 위해 IT산업의 주력산업과 융합을 통한 10대 전력산업 중심의 이행계획으로 'IT융합 발전 전략'을 마련했습니다. IT조선 융합 분야에서는 IT융합을 통한 선박건조(Digital Shipyard), 선박통합통신망(SAN)이 적용된 지능형 선박(Smart Ship), 항로최적화 등을 위한 선박운항 기술개발 등이 고려될 수 있습니다. 국제적으로 EU, 미국, 일본 등에서 대형 프로젝트를 통해 기술개발을 완료하고 e-Navigation 정책의 국제적 합의 도출을 기다리는 상황입니다. e-Navigation은 선박의 안전항해를 실현하기 위한 방법으로써 선박에 사용되는 IT기자재의 표준화와 항해사의 의사결정을 도울 수 있는 도구 개발에 핵심을 두고 있습니다. 이를 위해 선내 모둔 기자재는 네트워크에 연결되어 선박의 항행정보와 선박기자재의 운전정보 등이 실시간으로 모니터링 되고 용이하게 제어되어야 하며, 이러한 정보는 육상에서도 모니터링 되고 필요시 육상에서 항해사의 의사결정을 도울 수 있어야 합니다. 정보교환을 위해서는 선박과 육상(Ship-Shore), 선박과 선박(Ship-Ship) 사이에 끊임없고 신뢰할 수 있는 통신채널이 유지되어야만 가능합니다. 이를 기반으로 e-Navigation의 최종 실현목표인 해양환경보호 및 항해 안전과 선박의 안전을 달성할 수 있으므로 표준화 분야도 이 범주 내에서 이루어져야 할 것입니다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6C
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• pp.611-618
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• 2009

Recently, an indoor location-aware technology has been focused on as a key technology for context awareness in ubiquitous computing environments. The conventional Cricket system was designed with a non-centralized architecture, which has advantages in terms of user privacy, deployment, scalability, decentralized administration, network heterogeneity, and low cost. In this paper, an indoor location system based on TDOA between RF and ultrasound signals is designed, which improves the Cricket system. A 2.4GHz frequency is employed for transmitting RF messages, which is in an ISM band. The beaconing frequency is doubled to enhance the channel utilization rate. The ultrasonic pulse duration is optimized to increase the coverage of ultrasonic signals. The function of calculating location coordinates is embedded in a listener. The location-update rate and location accuracy are also improved.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.4
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• pp.833-837
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• 2012

This paper proposes a DRAM data retention time enhancement method that minimizes silicon loss and undercut at STI sidewall by reducing the SC1 (Standard Cleaning) time. SC1 time optimization debilitates the parasitic electric field in STI's top corner, which reduces an inverse narrow width effect to result in reduction of channel doping density without increasing the subthreshold leakage of cell Tr. Moreover, it minimizes the electric field in depletion area from cell junction to P-well, increasing yield or data retention time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2267-2271
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• 2011

This study was focused on getting p-type copper-oxide thin-film semiconductors suitable for p-channel thin-film transistors. Vacuum thermal evaporation and thermal annealing were used to get copper-oxide thin-film semiconductor having properties adoptable as an active layer of thin-film transistors. n-type thin films having electron carrier density of about $10^{22}\;cm^{-3}$ before thermal annealing was converted to p-type thin films having hole carrier density of about $10^{16}\;cm^{-3}$ as the thermal annealing conditions were optimized.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.11
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• pp.30-35
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• 2010

Network coding is a new research area that may have interesting applications in practical networking systems. With network coding, intermediate nodes may send out packets that are linear combinations of previously received information. The exploration of numerical, theoretical and operational networking issues from new perspectives that consider coding at network nodes. We have presented a network coding approach which asymptotically achieves optimal capacity in multi-source multicast networks. Our analysis uses connections that we make between network coding. In this paper we analysed with and without network coding performance. Also we discussed the simulation results on network coding with linear optimization problem and it shows how network coding can be used.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.8
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• pp.1673-1678
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• 2009

Multicast can transmit data packet to multiple terminals by using only one transmission and enhances the system performance. However, the multicast transmission rate is fixed and the system performance is not optimized. In this paper, we propose an adaptive multicast rate control method. In the proposed method, orthogonal subcarrier is assigned to each terminal. Each terminal informs the channel status using the allocated subcarrier. Transmitter selects the optimal rate using the feedback information. With the proposed adaptive rate control method, the system performance is enhanced compared with the legacy multicast method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.794-799
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• 2015

To manage cell outage problem in indoor wireless communication systems, we should resolve the problem of abrupt network failure quickly. In this paper, we propose a near-optimal cell outage management (NoCOM) scheme to support seamless services to users. In consideration of system throughput, user fairness, and the guarantee of QoS simultaneously, the NoCOM scheme finds the solution of subchannel and power allocations using a non-convex optimization technique and allocates radio resources to users iteratively. Through intensive simulations, we verify the outstanding performances of the proposed NoCOM scheme with respect to the average cell capacity, user fairness, and computational complexity.

• The Transactions of the Korea Information Processing Society
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• v.7 no.9
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• pp.2980-2993
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• 2000

In order to achieve the rapid deployment of services. B-ISON network is being combined with terrestrial ATM and satellite network. Cell delay variation (CDV) generated by the difference of transfer mode between TOMA and ATM deteriorates transmission quality of the network system. We proposed the Partial Timestamps algorithm to supplement the problems of existing COV compensation methods. To minimize CDV and to utilize the satellite channels efficiently. only the optimized timestamps of a few cells within a control unit time of TDMA are selected and transmitted to the receiving earth station. The COV compensating efficiency of Partial Timestamps is evaluated by simulation. It is confirmed that CDV compensation capability of the proposed mechanism is superior to the other methods.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.463-470
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• 2012

This paper proposes a new profit popularity-based segment caching control mechanism for assuring a consecutive streaming QoS (Quality of Service) in the wireless channel. Then, the proposed mechanism operates SSCP (Single Segment Caching Profit) and MSCP (Multiple Segment Caching Profit) for assuring a QoS. SSCP and MSCP is to optimize the cache performance when is performed the streaming in the proxy. The proposed mechanism simulated to evaluate such mechanisms as fixed-partition mechanism, weight-based mechanism, SSCP, and MSCP. Simulation results show that the proposed mechanism has superior performance compared to other mechanisms.