• Title, Summary, Keyword: spectrum

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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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Short Term Spectrum Trading in Future LTE Based Cognitive Radio Systems

  • Singh, Hiran Kumar;Kumar, Dhananjay;Srilakshmi, R.
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.1
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    • pp.34-49
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    • 2015
  • Market means of spectrum trading have been utilized as a vital method of spectrum sharing and access in future cognitive radio system. In this paper, we consider the spectrum trading with multiple primary carrier providers (PCP) leasing the spectrum to multiple secondary carrier providers (SCP) for a short period of time. Several factors including the price of the resource, duration of leasing, and the spectrum quality guides the proposed model. We formulate three trading policies based on the game theory for dynamic spectrum access in a LTE based cognitive radio system (CRS). In the first, we consider utility function based resource sharing (UFRS) without any knowledge of past transaction. In the second policy, each SCP deals with PCP using a non-cooperative resource sharing (NCRS) method which employs optimal strategy based on reinforcement learning. In variation of second policy, third policy adopts a Nash bargaining while incorporating a recommendation entity in resource sharing (RERS). The simulation results suggest overall increase in throughput while maintaining higher spectrum efficiency and fairness.

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 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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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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Development of Korean Standard Horizontal Design Spectrum Based on the Domestic and Overseas Intra-plate Earthquake Records (국내외 판내부 지진기록을 이용한 한국 표준수평설계스펙트럼의 개발)

  • Kim, Jae Kwan;Kim, Jung Han;Lee, Jin Ho;Heo, Tae Min
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.6
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    • pp.369-378
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    • 2016
  • The design spectrum for Korea, which is known to belong to an intra-plate region, is developed from the ground motion records of the earthquakes occurred in Korea and overseas intra-plate regions. The horizontal spectrum is defined as geometric mean spectrum, GMRotI50. From the statistical analysis of the geometric mean spectra, a mean plus one standard deviation spectrum in lognormal distribution is obtained. Regression analysis is performed on this curve to determine the shape of spectrum including transition periods. The developed design spectrum is valid for the estimation both spectral acceleration and displacement.

Bidding, Pricing, and User Subscription Dynamics in Asymmetric-Valued Korean LTE Spectrum Auction: A Hierarchical Dynamic Game Approach

  • Jung, Sang Yeob;Kim, Seong-Lyun
    • Journal of Communications and Networks
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    • v.18 no.4
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    • pp.658-669
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    • 2016
  • The tremendous increase in mobile data traffic coupled with fierce competition in wireless industry brings about spectrum scarcity and bandwidth fragmentation. This inevitably results in asymmetric-valued long term evolution (LTE) spectrum allocation that stems from different timing for twice improvement in capacity between competing operators, given spectrum allocations today. This motivates us to study the economic effects of asymmetric-valued LTE spectrum allocation. In this paper, we formulate the interactions between operators and users as a hierarchical dynamic game framework, where two spiteful operators simultaneously make spectrum acquisition decisions in the upper-level first-price sealed-bid auction game, and dynamic pricing decisions in the lower-level differential game, taking into account user subscription dynamics. Using backward induction, we derive the equilibrium of the entire game under mild conditions. Through analytical and numerical results, we verify our studies by comparing the latest result of LTE spectrum auction in South Korea, which serves as the benchmark of asymmetric-valued LTE spectrum auction designs.

Identifying the Winner's Curse in the First Spectrum Auction in the Republic of Korea Using an Event Study Approach

  • Lee, Hyeongjik;Seol, Seongho;Kweon, Soocheon
    • ETRI Journal
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    • v.35 no.6
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    • pp.1126-1133
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    • 2013
  • The first spectrum auction in the Republic of Korea is attention-worthy owing to the fierce competition for the only 1.8-GHz spectrum license, the winning bidder of which was suspected of overpaying for its acquisition. This study empirically investigates the existence of a "winner's curse" in the first Korean spectrum auction by using a standard event study methodology. The results show that both the winner and loser experienced significant positive returns on the completion day of the auction. The results imply that there was no winner's curse in the auction and that the losing firm might increase its competitive advantage by acquiring other spectrum licenses despite failing to achieve its initial target spectrum. Therefore, these results suggest that regulators may need to consider bringing about positive short-term wealth benefits to all bidders by appropriately designing a spectrum auction, such as by performing multiband auctions.