• Title, Summary, Keyword: spectrum

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Evaluation of Response Spectrum Shape Effect on Seismic Fragility of NPP Component (스펙트럼 형상이 원전 기기 지진취약도에 미치는 영향 평가)

  • 최인길;서정문;전영선;이종림
    • Journal of the Earthquake Engineering Society of Korea
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    • v.7 no.4
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    • pp.23-30
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    • 2003
  • The result of recent seismic hazard analysis indicates that the ground motion response spectra for Korean nuclear power plant site have relatively large frequency acceleration contents. In the ordinary seismic fragility analysis of nuclear power plant structures and equipments, the safety margin of design ground response spectrum is directly used as a response spectrum shape factor. The effects of input response spectrum shape on the floor response spectrum were investigated by performing the direct generation of floor response spectrum from the ground response spectrum. The safety margin included in the design ground response spectrum should be considered as a floor response spectrum shape factor for the seismic fragility analysis of the equipments located in a building.

Analysis of Radio Spectrum Charges based on Economic Value (주파수의 경제적 가치를 고려한 할당대가 산정기준 분석)

  • Jang, Hee-Seon;Yeo, Jae-Hyun;Lee, Kwang-Hee;Choi, Ki-Seok
    • Journal of Korean Institute of Industrial Engineers
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    • v.34 no.2
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    • pp.216-222
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    • 2008
  • The determination of spectrum charges for the operators is a main issue to efficiently manage the limited radio spectrum resources. In this paper, we propose a model to compute the optimal charges for radio spectrum usage. The objective is to determine that will maximize the spectrum charges, and decision variables of ratios for actual or estimated revenues are considered. The spectrum charges are maximized under satisfying the least profit for operators based on Log-Linear demand function. The parameters of actual sales and minimum profit of operators are analyzed to make an efficient management for radio spectrum. The results show that the spectrum charges increase as the actual sales increase, but it decrease as the required minimum profit of operator increases. It is also observed that the government should increase the ratio for estimated sales if anticipating the poor market in the future, otherwise they should increase the ratio for actual sales to maximize the spectrum charges.

An Oligopoly Spectrum Pricing with Behavior of Primary Users for Cognitive Radio Networks

  • Lee, Suchul;Lim, Sangsoon;Lee, Jun-Rak
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.4
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    • pp.1192-1207
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    • 2014
  • Dynamic spectrum sharing is a key technology to improve spectrum utilization in wireless networks. The elastic spectrum management provides a new opportunity for licensed primary users and unlicensed secondary users to efficiently utilize the scarce wireless resource. In this paper, we present a game-theoretic framework for dynamic spectrum allocation where the primary users rent the unutilized spectrum to the secondary users for a monetary profit. In reality, due to the ON-OFF behavior of the primary user, the quantity of spectrum that can be opportunistically shared by the secondary users is limited. We model this situation with the renewal theory and formulate the spectrum pricing scheme with the Bertrand game, taking into account the scarcity of the spectrum. By the Nash-equilibrium pricing scheme, each player in the game continually converges to a strategy that maximizes its own profit. We also investigate the impact of several properties, including channel quality and spectrum substitutability. Based on the equilibrium analysis, we finally propose a decentralized algorithm that leads the primary users to the Nash-equilibrium, called DST. The stability of the proposed algorithm in terms of convergence to the Nash equilibrium is also studied.

Spectrum Hole Utilization in Cognitive Two-way Relaying Networks

  • Gao, Yuan;Zhu, Changping;Tang, Yibin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.3
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    • pp.890-910
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    • 2014
  • This paper investigates the spectrum hole utilization of cooperative schemes for the two-way relaying model in order to improve the utilization efficiency of limited spectrum holes in cognitive radio networks with imperfect spectrum sensing. We propose two specific bidirectional secondary data transmission (BSDT) schemes with two-step and three-step two-way relaying models, i.e., two-BSDT and three-BSDT schemes, where the spectrum sensing and the secondary data transmission are jointly designed. In the proposed cooperative schemes, the best two-way relay channel between two secondary users is selected from a group of secondary users serving as cognitive relays and assists the bi-directional communication between the two secondary users without a direct link. The closed-form asymptotic expressions for outage probabilities of the two schemes are derived with a primary user protection constraint over Rayleigh fading channels. Based on the derived outage probabilities, the spectrum hole utilization is calculated to evaluate the percentage of spectrum holes used by the two secondary users for their successful information exchange without channel outage. Numerical results show that the spectrum hole utilization depends on the spectrum sensing overhead and the channel gain from a primary user to secondary users. Additionally, we compare the spectrum hole utilization of the two schemes as the varying of secondary signal to noise ratio, the number of cognitive relays, and symmetric and asymmetric channels.

On a Pitch Alteration Technique by Cepstrum Analysis of Flattened Excitation Spectrum (평탄화된 여기 스펙트럼에서 켑스트럼 피치 변경법에 관한 연구)

  • 조왕래
    • Proceedings of the Acoustical Society of Korea Conference
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    • pp.159-162
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    • 1998
  • Speech synthesis coding is classified into three categories: waveform coding, source coding and hybrid coding. To obtain the synthetic speech with high quality, the synthesis by waveform coding is desired. However, it is difficult to apply waveform coding to synthesis by syllable or phoneme unit, because it does not divide the speech into excitation and formant component. Thus it is required to alter the excitation in waveform coding for applying waveform coding to synthesis by rule. In this paper we propose a new pitch alteration method that minimizes the spectrum distortion by using the behavior of cepstrum. This method splits the spectrum of speech signal into excitation spectrum and formant spectrum and transforms the excitation spectrum into cepstrum domain. The pitch of excitation cepstrum is altered by zero insertion or zero deletion and the pitch altered spectrum is reconstructed in spectrum domain. As a result of performance test, the average spectrum distortion was below 2.29%.

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A Probabilistic Interpretation of the KL Spectrum

  • Seongbaek Yi;Park, Byoung-Seon
    • Journal of the Korean Statistical Society
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    • v.29 no.1
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    • pp.1-8
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    • 2000
  • A spectrum minimizing the frequency-domain Kullback-Leibler information number has been proposed and used to modify a spectrum estimate. Some numerical examples have illustrated the KL spectrum estimate is superior to the initial estimate, i.e., the autocovariances obtained by the inverse Fourier transformation of the KL spectrum estimate are closer to the sample autocovariances of the given observations than those of the initial spectrum estimate. Also, it has been shown that a Gaussian autoregressive process associated with the KL spectrum is the closest in the timedomain Kullback-Leibler sense to a Gaussian white noise process subject to given autocovariance constraints. In this paper a corresponding conditional probability theorem is presented, which gives another rationale to the KL spectrum.

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Design Issues of Spectrum Sensing in Cognitive Radio Networks

  • Kang, Bub-Joo
    • Journal of information and communication convergence engineering
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    • v.9 no.2
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    • pp.166-171
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    • 2011
  • This paper investigates the design issues of spectrum sensing in the cognitive radio (CR) networks of opportunistic unlicensed spectrum access. The cognitive radios can perform a communication using the incumbent user spectrum band without the interference caused by the cognitive radio users. In this case, the cognitive radios must know the real-time radio environments of the incumbent user spectrum band using the spectrum sensing, beacon signal, and geo-location database access. Then in this paper, we are going to provide spectrum sensing issues which include the sensing techniques, the regulatory requirements, the analysis of DTV detection threshold, and main considerations associated with the spectrum sensing design in cognitive radio systems. Also, this paper introduces design trade-offs in order to optimize the sensing parameters such as sensing time and sensing complexity.

A study on the Capacity Spectrum for Seismic Performance Evaluation of Bridge (교량의 내진성능 평가를 위한 역량스펙트럼 적용 연구)

  • Park, Yeon-Soo;Lee, Byung-Geun;Kim, Eung-Rok;Suh, Byung-Chul;Park, Sun-Joon;Choi, Sun-Min
    • Proceedings of the KSR Conference
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    • pp.1012-1017
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    • 2008
  • In this study, We examine closely the capacity spectrum method which a kind of displacement-based method evaluated by displacement of structure as an alternative to the load-based analysis method. The displacement-based method can easily review the strength of structure, seismic performance, ductility. Seismic performance by using capacity spectrum method is divided into design response spectrum and capacity spectrum. We can diagram design response spectrum by deciding the design seismic factor depending on performance target, site classification, seismic level, return period as UBC-97. Capacity spectrum is a load-displacement curve obtained by Push-over analysis considering the geometric parameter and the material parameter. We execute the seismic performance evaluation by using the capacity spectrum method to reinforced concrete pier which has been seismic design. As a result, We confirmed that there is a yield point and a ultimate point close by design response spectrum of UBC-97.

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실물옵션기법을 적용한 주파수관리정책에 관한 연구 - 휴대인터넷 관련 2.3GHz 대역을 중심으로 -

  • Lee, Jeong-Dong;Kim, Min-Jeong;Jeong, Jong-Uk
    • Proceedings of the Technology Innovation Conference
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    • pp.108-131
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    • 2004
  • Having the characteristics of public goods, Radio Spectrum had been controlled by Government Authorities. In the past, technological side of spectrum, such as cross protection, was the main concern, but as the telecommunication industry is developing gradually, economic side of spectrum is becoming an important part. To uplift the Economic efficiency of spectrum management policy, clarifying the basic value of spectrum is one of the most important things. Also, both government authorities and spectrum licensees will have to choose license or investment under uncertainties such as license timing, time to market, technology standard, and so on. Considering all things, this paper gives the value to the spectrum by real options theory, which is a powerful method concerning uncertainty, especially for government, And we applied it to a specific spectrum band for the portable Internet in Korea. These results can provide information about the technological standard, optimal market-entry time as well as the value of spectrum for the portable Internet.

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A Study on Policy Improvement for Efficient Utilization of Spectrum Usage Fee (전파사용료의 효율적 운용을 위한 제도 개선에 대한 연구)

  • Park, Jae-Chon;Yang, Je-Min
    • Journal of Digital Convergence
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    • v.6 no.2
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    • pp.1-12
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    • 2008
  • The spectrum usage fee has been imposed on spectrum users. The objective of the fee is spectrum management, so it is important to utilize it efficiently. Our study focused on how to efficiently utilize the spectrum usage fee. For this purpose it tried to found what the preconditions are for the efficient utilization, and analyzed current execution. The study showed that it did not comply with those preconditions, and produced policy recommendations. The authors expect that policy recommendations this study brought up will contribute to improve the policy process how to collect and use the spectrum usage fee.

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