• Proceedings of the KSR Conference
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• 2008.11b
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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.

• Electronics and Telecommunications Trends
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• v.38 no.5
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• pp.100-113
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• 2023

This study was aimed to derive implications in terms of competition to establish a reasonable spectrum policy for fifth-generation (5G) spectrum allocation through an in-depth analysis of C-band spectrum auctions. As a result of examining auctions in five countries, namely, Belgium, Sweden, Canada, Brazil, and Hong Kong, we identified various characteristics. First, the minimum bandwidth that is essential for service competition is guaranteed. Second, in Brazil, the network construction cost of mobile network operators is regarded as a part of the spectrum price. Third, a joint allocation of spectrum is permitted in Sweden, and spectrum sharing after allocation for 5G services is allowed in Canada. Finally, the reserved spectrum is provided for new service providers in Belgium and Canada. Our findings may provide insights for establishing policies of 5G spectrum allocation and competition in the telecommunications service market in Korea.

• 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.

• Broadcasting and Media Magazine
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• v.11 no.1
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• pp.68-77
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• 2006

The Cognitive Radio (CR) technology is a promising solution for exploiting the limited spectrum resources and providing flexibility of spectrum usage. Future interactive broadcasting service can be realized by utilizing CR concept, since the up-link return channel can be found by the spectrum sensing method, which is core functional block of the CR system. In this paper, the spectrum sensing technologies of CR system is presented. First the system architecture of the CR with spectrum sensing block is presented. The suggested spectrum sensing technique consists of the coarse and the fine spectrum sensing. The coarse spectrum sensing technique adopted the wavelet transform to provide the multi-resolution sensing feature - Multi-Resolution Spectrum Sensing (MRSS). The fine spectrum sensing technique uses the beneficial properties of the autocorrelation function Analog Auto-Correlation (AAC). The simulation results for the proposed sensing technologies are presented for various incumbent signals.

• 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.

• 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.

• Electronics and Telecommunications Trends
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• v.37 no.5
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• pp.70-81
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• 2022

This study derived implications regarding competition policy to establish a reasonable spectrum allocation draft of a 3.7 GHz spectrum band by indepth analysis of 5G spectrum auctions. The following general features were identified by examining auctions of three countries, including the United States, United Kingdom, and Denmark, were completed in 2021. First, securing the minimum bandwidth that is essential for service competition was guaranteed by applying the spectrum cap. Second, a continuous spectrum band was allocated to all mobile network operators. Third, certain requirements were implemented to encourage the expansion of 5G service coverage. The spectrum cap that was implemented in Korea during the most recent spectrum auction was ineffective regarding competition policy. Additionally, it is anticipated that the allocation of 3.7-4.0 GHz spectrum will considerably impact market competition because the continuity of spectrum band is different among mobile service operators. Therefore, it is time to discuss promoting the 5G service competition in Korea by revising related laws.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1261-1271
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• 2009

Emergence of new mobile communication services has generated new demand for spectrum. Because spectrum is a scarce public resource, demand for spectrum would exceed supply. As the demand for spectrum grows, the spectrum management policy becomes one of the most important issues in mobile telecommunications industry. Huge license charges for spectrum usage may obstruct the growth of mobile telecommunications industry. We analyze spectrum charges by international comparison for the case of 3G mobile telecommunication spectrum assignment. There are mainly two types of methods in spectrum assignment of 3G service, one is the auction and the other is the beauty contest. This article aims to analyze factors which influence on spectrum charges and to study the characteristic of spectrum charges of some selected countries. This study suggests the multiple regression model about spectrum charges.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.8
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• pp.849-859
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• 2013

This paper explores the policy alternatives to promote efficient use of spectrums for public use and terrestrial broadcasting, which are essential to provide spectrum for mobile broadband services. To this end, recent overseas spectrum management policies are introduced and utilized to provide domestic policy alternatives. For the efficient use of spectrum for public use, policy alternatives such as detailed survey of current usage of spectrum for public use, levying the opportunity cost, installment of spectrum efficiency fund, providing incentives for the efficient use of spectrum for military use, and introduction of shared use are proposed. For the efficient use of spectrum for terrestrial broadcasting, short-term policy alternative such as change of contribution rate base of the broadcasting - telecommunications development fund is proposed. For long-term policy alternatives, change of spectrum provision from designation to allocation for the spectrum for commercial terrestrial broadcasting and introduction of administered incentive pricing to public terrestrial broadcasting are proposed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.3
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• pp.50-59
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• 2011

In this paper, we present a spectrum sensing method by exploiting the relationship of previous and current detected data sets in frequency domain. Most of the traditional spectrum sensing methods only consider the current detected data sets of Primary User (PU). Previous state of PU is a kind of conditional probability that strengthens the reliability of the detector. By considering the relationship of the previous and current spectrum sensing, cross entropy-based spectrum sensing is proposed to detect PU signal more effectively, which has a strengthened performance and is robust. When previous detected signal is noise, the discriminating ability of cross entropy-based spectrum sensing is no better than conventional entropy-based spectrum sensing. To address this problem, we propose an improved cross entropy-based frequency-domain spectrum sensing. Regarding the spectrum sensing scheme, we have derived that the proposed method is superior to the cross entropy-based spectrum sensing. We proceed a comparison of the proposed method with the up-to-date entropy-based spectrum sensing in frequency-domain. The simulation results demonstrate the performance improvement of the proposed spectrum sensing method.