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A Novel Variable-Speed Renewable-Energy Generation System of Induction Generator and PWM Converter for Small-Scale Hybrid Power Applications

  • Ahmed, Tarek;Nishida, Katsumi;Lee, Hyun-Woo;Nakaoka, Mutsuo
    • Proceedings of the KIEE Conference
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    • 2005.07b
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    • pp.1339-1342
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    • 2005
  • This paper presents a simple AC-DC power conditioner for a squirell-cage induction generator(IG) operating under variable shaft speeds. The necessary reactive power for the IG system is supplied by means of a capacitor bank and a voltage-source PWM converter. Using a capacitor bank to transfer the reactive power to the IG under the rated speed and no-load conditions starts the IG operation and reduces the PWM power converter size. A simple control compensating for changes in the electrical loads as well as the variation in speed was developed to regulate the voltages of the IG system by controlling the rotor flux through its reactive and active currents control implementation. This proposed power conditioning scheme can be used efficiently as a wind power generation system where the output voltage of the IG is maintained constant voltage despite the variable frequency and the DC bus voltage of the PWM converter can be used for either DC applications such as battery charging or AC power applications with 60/50 Hz by connecting a stand alone inverter. The experimental and simulated operating performance results of a 5 kW IG scheme at various speeds and leads are presented.

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Improvement of the storage coefficient estimating mehod for the clark model (Clark 단위도의 저류상수산정방법의 개선)

  • 윤태훈;박진원
    • Proceedings of the Korea Water Resources Association Conference
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    • 2002.05b
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    • pp.1334-1339
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    • 2002
  • The objective of this study is to help practicing engineers easily use the Clark model which is used for estimating the magnitude of design flood for small stream. A representative unit hydrograph was derived on the basis of the past rainfall-runoff data and unit hydrographs, and the storage coefficient of Clark model was estimated by using hydrograph recession analysis. Since the storage coefficient(K) is a dominating factor among the parameters of Clark method, a mulitple regression formula, which has the drainage area, main channel length and slope as parameters, is propsed to estimate K value of a basin where measured data are missing. The result of regression analysis showed that there is a correlation between a storage coefficient(K) and aforemetioned three parameters in homogenious basins. A regression formular for K was derived using these correlations in a basin of Han River, Nakdong River, Young River, Kum River and Sumjin River

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Probing the Functional Motifs of Escherichia coli 5S rRNA in Relation to 16S rRNA Using a SELEX Experiment

  • 고재형;조봉래;안정근;이용훈;박인원
    • Bulletin of the Korean Chemical Society
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    • v.20 no.11
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    • pp.1335-1339
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    • 1999
  • The function of 5S rRNA, a constituent of a large subunit of ribosome, is not clearly known yet. To identify RNA motifs interacting with 5S rRNA, and thereby to get an insight into the function of 5S rRNA in the ribosome, a SELEX (Systematic Evolution of Ligands by Exponential Enrichment) experiment was performed. RNA molecules binding to Escherichia coli 5S rRNA were selected from a 48-mer random sequence library through 12 rounds of selection, cloned, and sequenced. Two groups of the selected RNA molecules had the consensus sequences GCGG and GUGAAA, respectively, which are present in the segment, G688 through A696, of E. coli 16S rRNA. The gel mobility shift assay showed that 5S rRNA interacted with the 16S rRNA fragment containing the GCGG and GUGAAA sequences. The enzymatic protection experiment shows that the A29CCUGA34 and G51AAGUG56 sequences of 5S rRNA and the C680AGG683 and G688CGG691 sequences of the 16S rRNA fragment are involved in the interaction between the two RNA molecules. On the basis of this observation, we suggest that 5S rRNA and 16S rRNA play a role for the association of two ribosomal subunits.

Using the Mobile Cloud Universal Video Integrated Management System (모바일 클라우드를 이용한 범용 영상 통합 관리 시스템)

  • Jeong, Seong-woo;Park, You-hyun;Yu, Yun-sik
    • Proceedings of the Korea Information Processing Society Conference
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    • 2012.11a
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    • pp.1336-1339
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    • 2012
  • 최근 공공기관을 통해 CCTV 영상을 통합관리 하려는 움직임이 활발히 발생하고 있다. 하지만, CCTV의 수가 증가하고, 해상도가 높아지면서 통합관리시 저장비용, 검색비용 등의 문제가 예상되고 있다. 이러한 문제의 해결책으로 클라우드 컴퓨팅 기술을 들 수 있는데, 클라우드 컴퓨팅은 다양한 클라이언트 디바이스에서 필요한 시점에 인터넷을 이용해 공유 풀에 있는 서버, 스토리지, 애플리케이션, 서비스 등과 같은 IT 리소스에 쉽게 접근할 수 있는 것을 가능하게 하는 모델이다. 또한 모바일 클라우드 컴퓨팅은 클라우드 컴퓨팅과 다양한 모바일 기기를 결합하여 다양한 서비스를 제공하는 것이다. CCTV와 같은 영상을 생산하는 클라이언트를 모바일 클라우드의 단말로 보고, 영상 데이터를 클라우드 컴퓨팅을 이용하여 관리하면, 저가의 비용으로 대용량의 영상을 저장하는데 비용을 절감 할 수 있으며, 간단한 방법으로 병렬 처리로 검색을 할 수 있어, 검색 시간을 절감 할 수 있는 효과가 있다. 본 논문에서는 모바일 클라우드를 이용한 범용 영상 통합 관리 시스템 모델을 제안하고 이를 토대로 차량용 블랙박스 분야에 한정한 시스템 설계하고 구현하였다.

Identification of pathways and genes associated with cerebral palsy

  • Zhu, Qingwen;Ni, Yufei;Wang, Jing;Yin, Honggang;Zhang, Qin;Zhang, Lingli;Bian, Wenjun;Liang, Bo;Kong, Lingyin;Xuan, Liming;Lu, Naru
    • Genes and Genomics
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    • v.40 no.12
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    • pp.1339-1349
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    • 2018
  • Cerebral palsy (CP) is a non-progressive neurological disease, of which susceptibility is linked to genetic and environmental risk factors. More and more studies have shown that CP might be caused by multiple genetic factors, similar to other neurodevelopmental disorders. Due to the high genetic heterogeneity of CP, we focused on investigating related molecular pathways. Ten children with CP were collected for whole-exome sequencing by next-generation sequencing (NGS) technology. Customized processes were used to identify potential pathogenic pathways and variants. Three pathways (axon guidance, transmission across chemical synapses, protein-protein interactions at synapses) with twenty-three genes were identified to be highly correlated with CP. This study showed that the three pathways associated with CP might be the molecular mechanism of pathogenesis. These findings could provide useful clues for developing pathway-based pharmacotherapies. Further studies are required to confirm potential roles for these pathways in the pathogenesis of CP.

Effects of heat stress on body temperature, milk production, and reproduction in dairy cows: a novel idea for monitoring and evaluation of heat stress - A review

  • Liu, Jiangjing;Li, Lanqi;Chen, Xiaoli;Lu, Yongqiang;Wang, Dong
    • Asian-Australasian Journal of Animal Sciences
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    • v.32 no.9
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    • pp.1332-1339
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    • 2019
  • Heat stress exerts a substantial effect on dairy production. The temperature and humidity index (THI) is widely used to assess heat stress in dairy operations. Herein, we review the effects of high temperature and humidity on body temperature, feed intake, milk production, follicle development, estrous behavior, and pregnancy in dairy cows. Analyses of the effects of THI on dairy production have shown that body temperature is an important physiological parameter in the evaluation of the health state of dairy cows. Although THI is an important environmental index and can help to infer the degree of heat stress, it does not reflect the physiological changes experienced by dairy cows undergoing heat stress. However, the simultaneous measurement of THI and physiological indexes (e.g., body temperature) would be very useful for improving dairy production. The successful development of automatic detection techniques makes it possible to combine THI with other physiological indexes (i.e., body temperature and activity), which could help us to comprehensively evaluate heat stress in dairy cows and provide important technical support to effectively prevent heat stress.

Cetyl Trimethyl Ammonium Bromide-coated Nickel Ferrite Nanoparticles for Magnetic Hyperthermia and T2 Contrast Agents in Magnetic Resonance Imaging

  • Lee, Da-Aemm;Bae, Hongsubm;Rhee, Ilsum
    • Journal of the Korean Physical Society
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    • v.73 no.9
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    • pp.1334-1339
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    • 2018
  • Spherical nickel ferrite nanoparticles were synthesized using the thermal decomposition method and coated with cetyl trimethyl ammonium bromide (CTAB) after the synthesis. Transmission electron microscopy images showed that the average diameter of the particles was 9.40 nm. The status of the CTAB-coating on the surface of the particles was checked using Fourier-transform infrared spectroscopy. Their hysteresis curve showed that the particles exhibited a superparamagnetic behavior. The $T_1$ and the $T_2$ relaxations of the nuclear spins were observed in aqueous solutions of the particles with different particles concentrations by using a magnetic resonance imaging (MRI) scanner, which showed that the $T_1$ and the $T_2$ relaxivities of the particles in water were $0.57mM^{-1}{\cdot}s^{-1}$ and $10.42mM^{-1}{\cdot}s^{-1}$, respectively. In addition, using an induction heating system, we evaluated their potentials for magnetic hyperthermia applications. The aqueous solution of the particles with a moderate concentration (smaller than 6.5 mg/mL) showed a saturation temperature larger than the hyperthermia target temperature of $42^{\circ}C$. These findings show that the CTAB-coated nickel ferrite particles are suitable for applications as $T_2$ contrast agents in MRI and heat generators in magnetic hyperthermia.

Who Would Care for Post-Imperial Broken Society?: Harold Pinter's The Caretaker

  • Kim, Seong Je
    • Journal of English Language & Literature
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    • v.56 no.6
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    • pp.1339-1360
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    • 2010
  • An analogical reading of socio-historical context of Harold Pinter's The Caretaker employs some postcolonial discursive analyses of postimperial British capitalistic interests in their post war reconstruction. It is also concerned with causes of so-called broken society. The Caretaker dramatizes minimal actions: a tramp is invited by the elder brother; a job as caretaker is offered; he is reluctant to accept the first offer by the elder brother, but is willing to the second by the younger; eventually, he is excluded because he makes noises while dreaming. These trivial actions produce serious and critical speech acts with their socio-historical implications. The tramp Davies is socially and thereby existentially excluded from the centre of the cold, banished to even colder peripheries. The audience face to the question. Why is Davies excluded? This study tries to answer the question, uncovering deep-rooted capitalistic racism, and reading its symptoms. Even after 50 years The Caretaker was staged, post-imperial broken society tries to operate the betrayals of disparity between the cause and effect of what has gone wrong. Pinter confirms that the action of the play takes place in a house in west London. With the city of London as its capitalistic centre, British imperialism lavished much of its wealth which has only served sectional interests dividing people against themselves. Pinter dramatizes the root of broken society. On the one hand, Pinter foregrounds the very general conflicts between individuals and forms of power; on the other hand, he underlies the very specific strategies of socio-historical exploitation, domination and exclusion.

A Study on modifying OSPF protocol for wireless tactical backbone networks (무선 전술 백본망을 위한 OSPF 프로토콜 수정 방안)

  • Yoon-Young Sung;Sung-Sook Kook;Moon-Jeong Chang;Mee-Jeong Lee
    • Proceedings of the Korea Information Processing Society Conference
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    • 2008.11a
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    • pp.1336-1339
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    • 2008
  • 최근, 우리 군에서는 무선을 기반으로 하는 차세대 전술통신 체계인 전술 종합 정보 통신 체계 (TICN: Tactical Information Communication Network) 구축 사업을 진행하고 있다. 이 시스템의 백본 역할을 수행하는 TICN 전달망에서의 라우팅 알고리즘은 기존 인터넷에서 사용 중인 표준 라우팅 알고리즘과는 다른 특성이 요구된다. 즉 무선전송 링크의 특성 및 재밍 등의 영향으로 링크 상태가 불안정한 상황에서도 생존성과 안정성이 요구되는 군 전술망 환경에 적합하여야 하며, TICN 전달망의 자원 효율성도 최대화할 수 있어야 한다. 그러므로 본 논문에서는 기존의 인터넷 표준 라우팅 프로토콜들 중에서 네트워크 상태변화에 신속하게 대처할 수 있으며, 이미 널리 사용되고 있는 OSPF 프로토콜을 TICN 전달망에 적합한 라우팅 프로토콜이 되도록 수정하고자 한다. 이를 위해 라우팅 프로토콜의 대상 네트워크가 유선망에서 무선 전술 백본망으로 변경됨에 따라 튜닝될 필요가 있는 프로토콜 파라미터들을 추출하고, 시뮬레이션을 통해 추출한 파라미터들의 값들을 튜닝 하고자 한다.

Application of AC superimposed DC waveforms to bismuth electrorefining

  • Greg Chipman;Bryant Johnson;Devin Rappleye
    • Nuclear Engineering and Technology
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    • v.56 no.4
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    • pp.1339-1346
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    • 2024
  • Electrorefining in molten salts is used for purifying actinides. Optimizing electrorefining is key to minimizing processing time and radiological waste. One possible way of improving electrorefining efficiency is using an AC superimposed DC waveform. This waveform has demonstrated potential benefits in aqueous solutions but has never been utilized in a molten metal, molten salt application. This work investigates the effects of using an AC superimposed DC waveform on molten bismuth electrorefining in a molten LiCl-KCl-CaCl2 eutectic. Bismuth has been identified as a potential surrogate for plutonium electrorefining and a potential cathode in electrorefining used nuclear fuel (UNF). All electrorefining runs resulted in a high purity cathode ring and high yield with exception of the run using a low-frequency, high-amplitude superimposed AC waveform, which experienced some contamination and a lower yield. The other three AC superimposed DC runs experienced an average yield 6.7 % higher than the average yield of the DC runs. The electrorefining run using the high-frequency, high-amplitude superimposed AC signal had the highest yield. It is recommended in future studies to investigate the statistical variability of electrorefining yield and current efficiency and the impact of AC superimposed DC waveforms on solidified bismuth anodes.