• 제목/요약/키워드: essential spectrum

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Seismic Response Amplification Factors of Nuclear Power Plants for Seismic Performance Evaluation of Structures and Equipment due to High-frequency Earthquakes (구조물 및 기기의 내진성능 평가를 위한 고주파수 지진에 의한 원자력발전소의 지진응답 증폭계수)

  • Eem, Seung-Hyun;Choi, In-Kil;Jeon, Bub-Gyu;Kwag, Shinyoung
    • Journal of the Earthquake Engineering Society of Korea
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    • v.24 no.3
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    • pp.123-128
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    • 2020
  • Analysis of the 2016 Gyeongju earthquake and the 2017 Pohang earthquake showed the characteristics of a typical high-frequency earthquake with many high-frequency components, short time strong motion duration, and large peak ground acceleration relative to the magnitude of the earthquake. Domestic nuclear power plants were designed and evaluated based on NRC's Regulatory Guide 1.60 design response spectrum, which had a great deal of energy in the low-frequency range. Therefore, nuclear power plants should carry out seismic verification and seismic performance evaluation of systems, structures, and components by reflecting the domestic characteristics of earthquakes. In this study, high-frequency amplification factors that can be used for seismic verification and seismic performance evaluation of nuclear power plant systems, structures, and equipment were analyzed. In order to analyze the high-frequency amplification factor, five sets of seismic time history were generated, which were matched with the uniform hazard response spectrum to reflect the characteristics of domestic earthquake motion. The nuclear power plant was subjected to seismic analysis for the construction of the Korean standard nuclear power plant, OPR1000, which is a reactor building, an auxiliary building assembly, a component cooling water heat exchanger building, and an essential service water building. Based on the results of the seismic analysis, a high-frequency amplification factor was derived upon the calculation of the floor response spectrum of the important locations of nuclear power plants. The high-frequency amplification factor can be effectively used for the seismic verification and seismic performance evaluation of electric equipment which are sensitive to high-frequency earthquakes.

Linkage between Digital Down Converter System and Spectrum Sensing Method (Digital Down Converter 시스템과 스펙트럼 센싱 기법 연동 방안)

  • Hong, Moo-Hyun;Moon, Ki-Tak;Kim, Ju-Seok;Kim, Kyung-Seok
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.3
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    • pp.43-50
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    • 2010
  • DDC(Digital Down Converter) is a conversion technology to decimate to a lower sampling rate and DDC for the future development of communications technology has the necessary skills. So, it has been recognized in the wireless and the SDR(Software Defined Radio) system as essential components. In addition, research is underway on spectrum sensing for efficient communications environment due to the shortage of frequency resources. In this paper, the DDC systems were analyzed for CIC(Cascaded Integrator Comb) Filter, WDF(Wave Digital Filter), SRC(Sample Rate Conversion) each module. Moreover, we proposed a linkage effectively between DDC system and Spectrum Sensing for improve the efficiency of use of frequency by computer simulations. The simulation results of the DDC system was applied to the spectrum sensing capabilities. Also, performance and complexity of the results were derived and proposed system was the result of the check.

Adjacent Channel Coexistence of LTE in Unlicensed Spectrum (비면허 대역 LTE 시스템의 인접 대역 간섭 분석)

  • Lim, Su Hwan;Jung, Man Young;Lee, Sang-Wook
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.10
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    • pp.1879-1888
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    • 2015
  • This paper evaluates the adjacent channel coexistence issues between LAA(License Assisted Access) system and other system (e.g. Wi-Fi) system in 5 GHz unlicensed spectrum. LAA is a technology to achieve enhanced data rate by aggregating licensed and unlicensed spectrum using CA(Carrier Aggregation). The coexistence study is essential before deploying LTE in unlicensed spectrum to verify the impact of LTE on the existing system such as Wi-Fi including system in throughput and regulatory aspects. This paper evaluates and analyzes the RF requirements of LTE system using interference analysis of coexistence study when operating at adjacent frequency channel of the Wi-Fi system in order to minimize the impact of LTE system into Wi-Fi system.

A Study on the legal system in Korea satellite industry (한국 위성산업관련 법제도 고찰)

  • Jung, Sung-Min;Kim, Sun-Ihee
    • The Korean Journal of Air & Space Law and Policy
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    • v.27 no.1
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    • pp.123-156
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    • 2012
  • This study focuses on the satellite licenses and the requirements for satellite spectrum management (i.e. frequency allocation) in Korean satellite industry via comparative analyses against those cases in other developed countries, in order to provide complementary measures to the domestic satellite policies. The satellite industry is one of the main pursuits of a nation's efforts, and it shows distinct characteristics depending on various factors such as national defense and security. In addition, the industry is determined by the nation's market size as well as its international relationship. Consequently, the present study considers examples from various organizations and nations - including U.S.A, Japan, and ITU - and provides a hybrid policy that is well customized for the domestic market. This study looks at similarities between policies of other countries, and finds any supplements for domestic polices by specifying similar cases in others and analyzing their results. The main purpose of this study, therefore, is to find the best agreement for domestic policy with internal interpretation, rather accepting others. While the licensing method for domestic satellites need not be distinct from that of other nations, the case of using non-Korean licensed satellites must be complemented by the conditions in the domestic market. Furthermore, the spectrum management is essential to the nation's satellite industry since the spectrum is a scarce resource. As such, spectrum management that is carefully designed to incorporate the rapidly changing international market demand is crucial to provide a sufficient supply for domestic space industry. In the present study, we find that auction-like market based approaches together with measures to avoid exclusive uses of the scarce resource (e.g. share, leas and reallocation) would provide an excellent method for the domestic satellite industry.

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Pathophysiology of orthostatic tremor: a multiple case study (길입성 진전의 병태생리: 다증 증례 연구)

  • Seo, Man-Wook;Lee, Kwang-Woo
    • Annals of Clinical Neurophysiology
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    • v.4 no.1
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    • pp.44-50
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    • 2002
  • Introduction : Orthostatic tremor develops in the legs while standing up with no weakness, pain or imbalance in the leg and the tremor is characteristically not observed when walking. However there have been some confusions about orthostatic tremor in several aspects. For the past ten years, we have observed 4 patients with orthostatic tremor. In each case tests were performed to investigate the following three important areas of inquiry about orthostatic tremor. Firstly, whether this disorder is an independent diagnostic entity or a variant of essential tremor. Secondly, whether the progress of this disorder is specifically related with standing posture. Lastly, the nature of the pathophysiologic mechanism behind the appearance of the tremor when standing after the lapse of a certain latent period and its disappearance upon the commencement of walking. Methods : Our 4 cases of orthostatic tremor were studied clinically, electrophysiologically, and pharmacologically. Electrophysiological tests included tremor spectrum test and electromyography. Results : We observed the presence of this tremor in several other tonic postures, as well as its absence, in a vertically lifted position from all our cases. Our cases registered a variable tremor frequency between 5 and 12 Hz according to the tremor spectrum test and EMG. Furthermore all our 4 cases demonstrated patterns of both synchronous EMG activity and alternating EMG activity at various times in homologous muscles of both legs. Orthostatic tremor was improved significantly with propranolol as well as clonazepam. Conclusions : From the results of our study we drew the following conclusions. It is probable that orthostatic tremor is simply a variant of essential tremor rather than being an independent diagnostic entity and that in most cases its development is specifically related with muscle contraction rather than merely with the act of standing. Furthermore we discovered a clue in the previously described neural control mechanism that the nuclear bag fibers in the muscle spindle have lag time of several seconds in their response to muscle strength and that their baseline does not reset fully in rapidly moving muscle. This neural control mechanism could offer sufficient explanation for the phenomena of tremor appearance when standing and disappearance when walking in orthostatic tremor.

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Comparision of Anti-microbial Oils as Natural Preservatives (천연방부제로서 항균오일의 항균력 비교)

  • Kim, Mi-Jin;Jung, Taek-Kyu;Hong, In-Gi;Yoon, Kyung-Sup
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.32 no.2 s.57
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    • pp.99-103
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    • 2006
  • Natural essential oils showed anti-microbial activity on relatively broad spectrum of bacterial and fungal species. These materials had much more intensive anti-microbial activities than synthetic preservatives on C. albicans, A niger, and P. acnes, especially. In the experimental group, anti-microbial activity was order of tea tree oil (from Melaleuca alternifolia) > methylparaben > phytoncide (from Chamaecyparis obtusa). Also, natural essential oils had anti-oxidative and anti-inflammatory effects. These results suggest that natural essential oils can be useful as good cosmetic ingredients such as natural preservatives and anti-oxidants.

The energy spectrum and phantom image quality according to mammography target-filter combinations (유방촬영장치의 타깃에 따른 에너지스펙트럼 및 팬텀영상화질)

  • Jang, Seyoung;Oh, Wanggyun;Park, Jongbae;Jin, Gyehwan
    • Journal of the Korean Society of Radiology
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    • v.7 no.1
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    • pp.51-55
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    • 2013
  • When the X-ray energy is high, the X-ray penetrates the object and decrease the contrast of imaging, and when the X-ray energy is low, the X-ray increases the contrast of imaging but it is to be absorbed into the object, which in the long run increases patient's radiation exposure level. Therefore, appropriate X-ray energy is an essential element affecting the imaging quality and radiation exposure level. This study simulated the energy spectrums according to the target materials of mammography, and compared qualities of phantom imaging for the management of radiolographic quality and patient's radiation exposure level with the introduction of the mammography that employs diversified radiation quality by using new anode materials.

Novel State-of-Charge Estimation Method for Lithium Polymer Batteries Using Electrochemical Impedance Spectroscopy

  • Lee, Jong-Hak;Choi, Woo-Jin
    • Journal of Power Electronics
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    • v.11 no.2
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    • pp.237-243
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    • 2011
  • Lithium batteries are widely used in mobile electronic devices due to their higher voltage and energy density, lighter weight and longer life cycle when compared to other secondary batteries. In particular, a high demand for lithium batteries is expected for electric cars. In the case of the lithium batteries used in electric cars, driving distance must be calculated accurately and discharging should not be done below a level that makes it impossible to crank. Therefore, accurate information on the state-of-charge (SOC) becomes an essential element for reliable driving. In this paper, a novel method for estimating the SOC of lithium polymer batteries using AC impedance is proposed. In the proposed method, the parameters are extracted by fitting the measured impedance spectrum on an equivalent impedance model and the variation in the parameter values at each SOC is used to estimate the SOC. Also to shorten the long length of time required for the measurement of the impedance spectrum, a novel method is proposed that can extract the equivalent impedance model parameters of lithium polymer batteries with the impedance measured at only two specific frequencies. Experiments are conducted on lithium polymer batteries, with similar capacities, made by different manufacturers to prove the validity of the proposed method.

Recent NMR developments for pharmaceutical research

  • Lee, Kwanghwan
    • Journal of the Korean Magnetic Resonance Society
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    • v.20 no.1
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    • pp.27-35
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    • 2016
  • NMR spectrometer has been regarded as essential tool for structure elucidation in variable scientific field as like organic synthesis, natural product and macro protein research. Also NMR can be applied for defining dynamic behavior like ligand and receptor binding. One of advantage of research with NMR is that to be great confident to confirm structure and the measured sample could be recovered. Nevertheless NMR also has a weak points than other spectroscopic methods that require a lot of time for interpreting acquired spectrum and running time due to low sensitivity. For last two decade Bruker has developed hardware and software solution for overcome those weak points. In order to overcome low sensitivity Bruker introduced Cryo and Micro diameter probe head technology. And researcher can reduce the time for routine spectrum processing and interpretation works due to lots of introductions in software solutions for quantification, identification and statistics analysis. With four examples, this article describing those new hardware and software solutions in field of recent pharmaceutical research as follows. - New Horizons for NMR in the Biopharmaceutical Industry - The development and application of solid-state NMR spectroscopy (SSNMR) in pharmaceutical analysis - Assisted NMR Data Interpretation in Synthetic Chemistry - Complete Analysis of New Psychoactive Substances Using NMR.

A GENERALIZATION OF THE PRIME RADICAL OF IDEALS IN COMMUTATIVE RINGS

  • Harehdashti, Javad Bagheri;Moghimi, Hosein Fazaeli
    • Communications of the Korean Mathematical Society
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    • v.32 no.3
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    • pp.543-552
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    • 2017
  • Let R be a commutative ring with identity, and ${\phi}:{\mathfrak{I}}(R){\rightarrow}{\mathfrak{I}}(R){\cup}\{{\varnothing}\}$ be a function where ${\mathfrak{I}}(R)$ is the set of all ideals of R. Following [2], a proper ideal P of R is called a ${\phi}$-prime ideal if $x,y{\in}R$ with $xy{\in}P-{\phi}(P)$ implies $x{\in}P$ or $y{\in}P$. For an ideal I of R, we define the ${\phi}$-radical ${\sqrt[{\phi}]{I}}$ to be the intersection of all ${\phi}$-prime ideals of R containing I, and show that this notion inherits most of the essential properties of the usual notion of radical of an ideal. We also investigate when the set of all ${\phi}$-prime ideals of R, denoted $Spec_{\phi}(R)$, has a Zariski topology analogous to that of the prime spectrum Spec(R), and show that this topological space is Noetherian if and only if ${\phi}$-radical ideals of R satisfy the ascending chain condition.