http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Hoon Lee,Sang-Rim Lee,Kyoung-Jae Lee,Han-Bae Kong,Inkyu Lee IEEE 2015 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.14 No.9
<P>This paper investigates the optimal transmit beamforming designs for simultaneous wireless information and power transfer (SWIPT) in multiple-input single-output interference channels (IFC). Based on cooperation level among transmitters and receivsers, we classify the SWIPT IFC systems into two categories. First, we consider the IFC with partial cooperation, where only channel state information (CSI) is available at transmitters and receivers, but not the signal waveform. Second, we examine the IFC with signal cooperation, where both the CSI and the signal waveforms are known to transmitters and receivers. Then, for the both scenarios, we identify the Pareto boundary of the achievable rate-energy (R-E) region which characterizes the optimal tradeoff between the information rate and the harvested energy. To this end, the problems for maximizing the information rate are formulated with minimum required harvested energy constraint. To solve these non-convex problems, we introduce parameterization techniques for characterizing the R-E region. As a result, the original problem is separated into two subproblems, for which closed-form solutions are obtained by addressing the line search method. Finally, we provide numerical examples for the Pareto boundary of the R-E region through simulations.</P>
Downlink Vertical Beamforming Designs for Active Antenna Systems
Wookbong Lee,Sang-Rim Lee,Han-Bae Kong,Sunho Lee,Inkyu Lee IEEE 2014 IEEE TRANSACTIONS ON COMMUNICATIONS Vol.62 No.6
<P>In this paper, we study a vertical beamforming technique for multiple-input multiple-output downlink multi-user systems. In general, the transmit antenna gain is controlled by adjusting the boresight of antennas in directional antennas, and thus the cell average rate varies according to the angle of the boresight. First, we compute the tilting angles for directional antenna systems which maximize the cell average rate. To this end, the probability density function of a three-dimensional user distribution is derived. Based on the result, we analyze the average rate gain of active antenna systems over passive antenna systems for a single user case. Furthermore, for a multi-user active antenna system, beamforming designs to maximize the weighted sum rate are proposed by optimizing the transmit antenna gain and power allocation. Since finding joint optimal parameters requires prohibitively high computational complexity, we separate the optimization problem into two sub-problems of the vertical beamforming and the power allocation. Then a simple vertical beamforming algorithm based on a high signal-to-noise ratio assumption is presented. Also, for a multi-user passive antenna system, we provide a beamforming scheme based on a multi-sector concept. Simulation results show that the proposed beamforming schemes outperform the conventional beamforming schemes.</P>
IoT 센서 연동 운전 보조 음성 AI Agent Device 및 App
이하은(Haeun Lee),이시윤(Siyoon Lee),오인규(Inkyu OH),박경만(Kyeongman Park),신승연(Seungyun Shin),이수민(Sumin Lee),정서우(Seowoo Jeong),이민구(Mingu Lee) 한국HCI학회 2022 한국HCI학회 학술대회 Vol.2022 No.2
‘캐리’는 운전에 어려움을 느끼는 초보 운전자와 장롱면허자의 안전운전을 위해 고안된 어플리케이션이다. ‘캐리’ 어플과 차량용 인공지능 스피커를 통해서 보다 안전하고, 심리적으로 안정된 상황에서 운전을 할 수 있도록 돕는다. 또한, 본 기능을 공유-렌터카 업체와 연동함으로써, 교통사고 발생 빈도가 상대적으로 높은 초보 운전자들에게 합리적인 가격으로 운전 교습을 제공하고, 심리적 안정감을 증진시키는 것을 목표로 한다. 본 논문에서는 ‘캐리" 어플리케이션의 프로토타입을 디자인 하는 과정을 담았으며, 그 과정에서 이루어진 설문조사와 사용성 평가의 결과를 중심으로 기술하였다. 각 평가는 "캐리"가 사용자들의 니즈를 정화하게 충족시키고 있는지, 어플의 디자인이 사용자에게 직관적으로 이용되고 있는지에 대해서 알아보기 위해 진행되었다. 평가는 실제 주행 환경이 아닌 테이블 테스트로 진행되었으며, 현재는 모듈 완성 이후 테스트 차량을 통한 사용자 평가와 AI Agent Device 베타 버전 평가를 진행중이다.
롤투롤 나노임프린팅 및 금속 경사증착 기반 대면적 유연 기판 상 3D LSPR 구조의 연속적 제작 및 투명센서 소자 응용
위정섭(Jung-Sub Wi),오동교(Dong Kyo Oh),이성호(Sung Ho Lee),이승조(Seungjo Lee),이규태(Kyu-Tae Lee),김정대(Jeong Dae Kim),이재혁(Jae Hyuk Lee),안주현(Ju Hyun Ahn),이원석(Won Seok Lee),지강민(Kang Min Jee),박인규(Inkyu Park),곽문규(Moon 한국기계가공학회 2017 한국기계가공학회 춘추계학술대회 논문집 Vol.2017 No.4
Lee, Inkyu,Park, Jinwoo,Moon, Il Pergamon Press 2017 Energy Vol.140 No.1
<P><B>Abstract</B></P> <P>This study aims to develop an efficient cryogenic energy storage (CES) process using the exergy from liquefied natural gas (LNG) regasification. While LNG has low internal energy, it has high exergy because of its cryogenic characteristics, and much of this exergy is wasted in the process of regasification. Thus, this work focuses on the recovery of LNG cold exergy to store cryogenic energy using air as a working fluid. The cold exergy of LNG is transferred in two forms: cold transfer by heat exchange to liquefy air, and shaft work transfer by direct expansion of LNG to compress the air. Thermodynamic analysis of the proposed process is carried out in three exergy flow steps: the LNG regasification step, the air liquefaction step, and the air expansion step. In addition, the proposed system has an advantage which system can store and release the energy simultaneously. Therefore, daily produced energy by CES system is more than double compare to the most recent contributions that have divided operation modes for energy storage and release. This study not only proposes an efficient energy storage process that can generate power flexibly but also highlights further possibilities for performance enhancement by thermodynamic analysis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The integrated Cryogenic energy storage (CES) and liquefied natural gas (LNG) regasification process is proposed. </LI> <LI> Exergy efficiency of the air storage process is 94.2%, and the air release process is 61.1%. </LI> <LI> The specific power output per 1 kg of LNG is about 160.92 kJ. </LI> </UL> </P>
Precoder Designs for MIMO Gaussian Multiple Access Wiretap Channels
Lee, Hoon,Song, Changick,Moon, Jihwan,Lee, Inkyu IEEE 2017 IEEE Transactions on Vehicular Technology VT Vol.66 No.9
<P>This paper studies multiple-input multiple-output multiple access wiretap channels (MAC-WT) where an eavesdropper tries to tap the communication between multiple legitimate transmitters and a legitimate receiver. In this system, we propose precoder optimization methods at the transmitters in order to maximize the sum secrecy rate performance. Although this problem can be solved by the well-known difference of convex (DC) programming, we present a more efficient algorithm whose computational complexity ismuch lower than that of the conventional DC approach. By investigating the Karush-Kuhn-Tucker conditions, it is confirmed that the proposed low-complexity algorithm achieves the same performance as the conventional DC method. Our analysis also reveals that the proposed algorithm ensures global optimality for multiple-input single-output MAC-WT cases, while binary power control is optimal for single-input multiple-output scenarios. Simulation results demonstrate the efficacy of the proposed precoding methods.</P>
Lee, Inkyu,Moon, Il American Chemical Society 2017 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.56 No.10
<P>This study mainly focuses on the profit optimization of the natural gas liquefaction process considering extraction rate. The target process is the dual mixed refrigerant (DMR) process with 1 million tons per annum (MTPA) capacity. The liquefaction ratio and the amount of boil-off gas (BOG) varies according to the natural gas extraction rate to meet the liquefaction capacity. Therefore, utilizing produced BOG and minimizing wasted BOG is key from an economic point of view. This study performed profit optimization with various extraction rates. Moreover, the energy and cost optimizations are performed to analyze the extraction rate effect. As results for the profit maximization, the total compression energy requirement and the plant cost show optimum values between the energy and cost optimization results. The profit increases by 22.5% with 93.2% liquefaction ratio through the optimization. The result shows that producing BOG as the amount of the fuel requirement for the compression energy supply is the optimal extraction rate. Resultingly, the optimal design of the profit max DMR process is also found through the profit optimization.</P>
Lee, Inkyu,Kim, Sojin,Kim, Seh-na,Jang, Yoonsun,Jang, Jyongsik American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.19
<P>Highly fluorescent surface modified polyacrylonitrile nanoparticles (PAN NPs) of 50 nm diameter were fabricated for selective Cu<SUP>2+</SUP> sensing. After surface modification, the PAN NPs were converted to amidine/Schiff base dual-modified PAN nanoparticles (tPAN NPs) with a Cu<SUP>2+</SUP> sensing property and high QY (0.19). The selectivity of tPAN NPs for Cu<SUP>2+</SUP> is much higher than that of other metal ions due to the fact that amidine group on the surface of tPAN NPs has a higher binding affinity with Cu<SUP>2+</SUP>. The effect of other metal ions on the fluorescence intensity of the tPAN NPs was also studied, and other metal ions showed a low interference response in the detection of Cu<SUP>2+</SUP>. Furthermore, as a metal ion chelator, ethylenediaminetetraacetate can competitively interact with Cu<SUP>2+</SUP> to recover the quenched fluorescence of tPAN NPs. The tPAN NPs are easily introduced into cells and exhibit low toxicity, enabling their use as a fluorescence sensor for Cu<SUP>2+</SUP> in living cells. The tPAN NPs provide a new direction for the development of copper ion sensors in living cells.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-19/am504824n/production/images/medium/am-2014-04824n_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am504824n'>ACS Electronic Supporting Info</A></P>