• 전기전자학회논문지
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• 제3권1호
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• pp.50-56
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• 1999

본 논문은 정밀한 클락 지연을 발생하는 회로 기법을 제안하였다. 이 기법은 지연 체인을 다중 클락 주기에 록킹(Locking)시켜서 개별 지연단(Delay Stage)의 지연보다 작은 지연 해상도를 갖도록 하는 것이다. 이 기법으로 단위 셀이 750ps의 지연시간을 갖는 지연체인에서 DLL(Delay Locked Loop)을 이용하여 250ps의 지연간격을 갖는 지연 발생회로를 설계하였다. 제안한 회로는 지연체인이 클락 신호 주기의 3배에 록킹이 되도록 하였으며, 1.5um CMOS공정의 모의 실험을 통해 단위지연셀 지연시간의 1/3인 250ps의 지연간격을 발생함을 확인하였다.

• 전기학회논문지
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• 제57권10호
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• pp.1796-1801
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• 2008

In this paper, a new current based maximum power point tracking (CMPPT) method is proposed for a single phase photovoltaic power conditioning system and the current based MPPT modifies incremental conductance method. The current based MPPT method makes the entire control structure of the power conditioning system simple and uses an inherent current source characteristic of solar cell array. In addition, digital phase locked loop using an all pass filter is introduced to detect phase of grid voltage as well as peak voltage. Controllers about dc/dc boost converter, dc-link voltage, dc/ac inverter is designed for a coordinated operation. Furthermore, PI current control using a pseudo synchronous d-q transformation is employed for grid current control with unity power factor. 3kW prototype photovoltaic power conditioning system is built and its experimental results are given to verify the effectiveness of the proposed control schemes.

• Asian-Australasian Journal of Animal Sciences
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• 제26권9호
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• pp.1229-1236
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• 2013

India possesses a total buffalo population of 105 million out of which 26.1% inhabit Uttar Pradesh. The buffalo of Uttar Pradesh are described as nondescript or local buffaloes. Currently, there is no report about the genetic diversity, phylogenetic relationship and matrilineal genetic structure of these buffaloes. To determine the origin and genetic diversity of UP buffaloes, we sequenced and analysed the mitochondrial DNA D-loop sequences in 259 samples from entire Uttar Pradesh. One hundred nine haplotypes were identified in UP buffaloes that were defined by 96 polymorphic sites. We implemented neutrality tests to assess signatures of recent historical demographic events like Tajima's D test and Fu's Fs test. The phylogenetic studies revealed that there was no geographic differentiation and UP buffaloes had a single maternal lineage while buffaloes of Eastern UP were distinctive from rest of the UP buffaloes.

• 한국세라믹학회지
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• 제42권4호
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• pp.232-236
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• 2005

$LiNbO_{3}$ optical waveguide 구조를 neutral loop discharge plasma 방법으로 식각시 As과 $C\_{3}F_{8}$가 혼합된 가스 유량에 따른 식각속도와 표면조도 값의 특성을 관찰하였다. 식각 후 식각속도와 식각단면은 scanning electron microscopy로 비교 분석하였으며, 표면조도는 atomic force microscopy로 측정하였다. Ar과 $C_{3}F_{8}$가 혼합된 가스 유량비를 각각 0.1-0.5로 증가시킴에 따라 식각속도와 표면조도는 0.2에서 가장 높게 나타났으며, bias power를 증가함에 따라 300W에서 가장 우수한 식각속도와 가장 평탄한 표면 형상을 얻을 수 있었다.

• 항공우주시스템공학회지
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• 제16권3호
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• pp.93-98
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• 2022

본 논문에서는 풀 브릿지 인버터의 비선형성을 고려한 단상 영구자석 동기 전동기의 오픈 루프 기동성을 개선하기 위한 구형파 전압 주입 기법을 제안한다. 일반적으로 단상 영구자석 동기 전동기는 3상 교류기와 달리 풀 브릿지 인버터를 채택하고 있으며 대칭 공극으로 자기 회로를 설계할 경우, 영토크 지점의 특정 위치에서 기동이 불가능할 수 있기에 비대칭 공극 설계가 요구된다. 이러한 단상 영구자석 동기 전동기의 구동 특성상 센서리스 운전 모드의 오픈 루프 제어시 기동 실패의 가능성이 상당히 높다. 본 논문에서는 이러한 문제를 해결하기 위해 인버터의 비선형성을 고려한 구형파 전압을 인가하여 기동 성능을 개선하는 기법을 제안하고자 한다. 제안한 알고리즘은 다수의 실험을 통해 타당성을 검증하였다.

• 한국항공우주학회지
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• 제40권6호
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• pp.542-547
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• 2012

현재까지 대부분의 지상통제 소프트웨어는 단일 무인 항공기에 대한 자세, 위치, 상태의 수신 및 가시화와 항공기의 운용을 위한 조종 명령 및 임무 전송의 기능만 갖추고 있었다. 하지만 단일 무인기의 운용에서 다중 무인기의 운용으로 사용자의 요구가 확장됨에 따라 지상통제 소프트웨어도 다중 무인기의 운용을 위한 기능의 확장이 요구되고 있다. 본 연구에서는 다중 무인항공기의 운용을 위한 요구사항을 제시하고 이를 만족시키기 위한 지상통제 소프트웨어의 구조를 제안하였다. 우선, 제시된 상위 요구 성능을 분석하여 그에 따른 전체 구조를 정의하고, 이를 다시 세부 요구사항으로 설정하여 세부구조를 설계하였다. 마지막으로 PILS 환경에서 구성된 지상통제 소프트웨어의 기능을 검증하였다.

• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2003년도 제2차 연례학술대회 발표논문집
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• pp.26-51
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• 2003

Large scale protein interaction maps provide a new, global perspective with which to analyse protein function. PSIMAP, the Protein Structural Interactome Map, is a database of all the structurally observed interactions between superfamilies of protein domains with known three-dimensional structure in thePDB. PSIMAP incorporates both functional and evolutionary information into a single network. It makes it possible to age protein domains in terms of taxonomic diversity, interaction and function. One consequence of it is to predict the most important protein domain structure in evolution. We present a global analysis of PSIMAP using several distinct network measures relating to centrality, interactivity, fault-tolerance, and taxonomic diversity. We found the following results: ${\bullet}$ Centrality: we show that the center and barycenter of PSIMAP do not coincide, and that the superfamilies forming the barycenter relate to very general functions, while those constituting the center relate to enzymatic activity. ${\bullet}$ Interactivity: we identify the P-loop and immunoglobulin superfamilies as the most highly interactive. We successfully use connectivity and cluster index, which characterise the connectivity of a superfamily's neighbourhood, to discover superfamilies of complex I and II. This is particularly significant as the structure of complex I is not yet solved. ${\bullet}$ Taxonomic diversity: we found that highly interactive superfamilies are in general taxonomically very diverse and are thus amongst the oldest. This led to the prediction of the oldest and most important protein domain in evolution of lift. ${\bullet}$ Fault-tolerance: we found that the network is very robust as for the majority of superfamilies removal from the network will not break up the network. Overall, we can single out the P-loop containing nucleotide triphosphate hydrolases superfamily as it is the most highly connected and has the highest taxonomic diversity. In addition, this superfamily has the highest interaction rank, is the barycenter of the network (it has the shortest average path to every other superfamily in the network), and is an articulation vertex, whose removal will disconnect the network. More generally, we conclude that the graph-theoretic and taxonomic analysis of PSIMAP is an important step towards the understanding of protein function and could be an important tool for tracing the evolution of life at the molecular level.

• 한국정밀공학회지
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• 제13권9호
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• pp.114-129
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• 1996

This paper describes the whole development phase for the underwater vehicle actuating system with high hydroload torque disturbance. This includes requirement analysis, system modeling, control algorithm design, real time implementation, test and performance evaluations. As for driving control algorithms, fuzzy logic, variable structure and PD(Proportional-Differential) algorithm were designed and implemented on board controller using a single chip microprocessor. Intel 8797. And test and performance evaluation is carried out both single test and wystem integration test. We could confirm the basic performance of actuating system through the single test and gereral developing work of any actuating systems was finished with a single performance test of actuating system without system integration test. But, we suggested that system integration test be needed. System integration test is carried out using G/C HILS(Guidance and Control Hardware-In-the -Loop Simulation) which is constituted flight motion simulator, load simulator, real time host computer and the related subsystems such as inertial navigation system, power supply system and Guidance and Control Computer etc.. The most important practical contribution of this paper is that full system characteristics such as minimal control effort, enhancement of guidance and autopilot performance by the actuating system using G/C HILS technique are investigated. Through full running G/C HILS, in spite of the passing to single tests, some control algorithm resulted in failure as to stability of full system and system time frame.

• Journal of Microbiology and Biotechnology
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• 제9권4호
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• pp.436-442
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• 1999

The aeg-46.5 operon of Escherichia coli is induced by nitrate and anaerobic conditions. Positive regulators Fnr and NarP, and a negative regulator NarL control the expression of the aeg-46.5. It has two symmetry regions [6], one of which is located between +37 and +56 bp from the 5'end of the anaerobic transcription initiation site. In this study, mutagenized symmetry regions were transferred from plasmid to chromosome by homologous recombination to evaluate the mutation as a single copy in the fnr, narL, narP, and narL-narP double mutant background. The expressions of the aeg-46.5 operon with these mutations indicated that the control was not through the possible stem-loop structure. Whether there is a protein that mediates this control remains to be seen. The results from the narL-narP double mutant indicated that the anaerobic Fill induction was independent of NarL repression.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.182-182
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• 2014

Multiferroic materials have attracted much attention due to their own fascinating fundamental physical properties and potential technological applications to magnetic/ferroelectric data storage systems, quantum electromagnets, spintronics, and sensor devices. Among single-phase multiferroic materials, $BiFeO_3$, in particular, has received considerable attention because the enhanced ferromagnetism was found by the Fe-site ion substitution with magnetic ions. The structural, the magnetic and the ferroelectric properties of polycrystalline $BiFe_{1-x}Ni_xO_3$ (x=0, 0.01, 0.02, 0.03 and 0.05), which were prepared by the solid-state reaction and the rapid-sintering method, have been investigated. The x-ray diffraction patterns reveal that all the samples are in single phase and show rhombohedral structure with R3c space group. The magnetic properties are enhanced according to the doping content. The Ni-doped $BiFeO_3$ samples exhibit lossy P-E loop due to the oxygen vacancy. The leakage current density of Ni-doped samples (x=0.01 and 0.02) is increased by four orders of magnitude. On the other hand, the x=0.03 and 0.05 samples show the relative reduction of the leakage current.