• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권4호
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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.

• 전자통신동향분석
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• 제37권5호
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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.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.498-498
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• 2001

Seismic qualification of the Main Control Boards for nuclear power plants has been performed with the guideline of AS ME Section III. US NRC Reg. Guide and IEEE 344 code. The analysis model of the Main Control Boards is consist of beam. shell and mass element by using the finite element method. and, at the same time. the excitation forces and other operating loads for each model are encompassed with respect to different loading conditions. As the fundamental frequencies of the structure are found to be less than 33Hz. which is the upper frequency limit of the seismic load, the response spectrum analysis using ANSYS is performed in order to combine the modal stresses within the frequency limit. In order to confirm the structural and functional integrity of the major components, modal analysis theory is adopted to derive the required response spectrum at the component locations. As all the combined stresses obtained from the above procedures are less than allowable stresses and no mechanical or electrical failures are found from the seismic testing, it concludes the Main Control Boards is dynamically qualified for seismic conditions. Although the authors had confirmed the structural and functional integrity of both Main Control Boards and all the component, in this paper only the seismic analysis of the Main Control Board is introduced.

• Journal of Astronomy and Space Sciences
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• 제24권4호
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• pp.261-268
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• 2007

We have studied the temporal variation in the North-South asymmetry of the sunspot area during the period from 1874 to 2007. Though the 9-year periodicity is commonly reported, shorter periodicities is still under study. We employ the cepstrum analysis method to analyze the noisy power spectrum of the North-South asymmetry. We demonstrate that the cleaned power spectrum shows reduction of the spurious back-ground noise level. Some of short period peaks in the power spectrum disappear after deconvolution. It should be, however, pointed out that power spectrum might look less noisy because of a filtering process during deconvolution. We conclude by pointing out that a more sophisticate filtering algorithm is required to produce a precise and reliable periodicity estimate.

• 대한의용생체공학회:의공학회지
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• 제5권1호
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• pp.55-62
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• 1984

A digital spectrum analysis technique was used to estimate the tissue characteristic parameters (transmission velocity and attenuation coefficient) in the phantom study and the human liver's ultrasound scanning. The soft tissue equivalent phantom was made with the combination materials of agar, water, powdered graphite, and n-propyl alcohol. In the human study, twenty five normal subjects and three patients with liver diseases were studied using the ultrasonic reflection signals and the spectrum analysis method The following results were obtained; 1. The soft tissue-equivalent materical could be produced with various acoustic parameters by changing the composition amount of the powdered graphite and n-propyl alcohol. 2. Attenuation coefficients of normal human liver tissue were estimated to be 0. 36 dB/cm MHz$\pm$0.11. In patients with liver disese, tile attenuation coefficients were shown to be different from the above normal values.

• 산업경영시스템학회지
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• 제35권4호
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• pp.162-170
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• 2012

We propose a new priority discipline called the strict T-preemptive priority discipline, and derive the waiting time distributions of each class in the strict T-preemptive priority M/G/1 queue. Using this queueing analysis, we evaluate the performance of an opportunistic spectrum access in cognitive radio networks, where a communication channel is divided into time slots, a licensed primary user is assigned to one channel, and multiple unlicensed secondary users may opportunistically exploit time slots unused by the primary user. We also present a numerical example of the analysis of the opportunistic spectrum access where the arrival rates and service times distributions of each users are identical.

• 음성과학
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• 제5권1호
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• pp.63-80
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• 1999

In this paper, an adaptive method of dividing a speech signal into an initial, a medial and a final sound of the form of utterance utilized by evaluating extreme limits of short term energy and autocorrelation functions. By applying this method into speech signal composed of a consonant, a vowel and a consonant, it was divided into an initial, a medial and a final sound and its feature analysis of sample by LPC were carried out. As a result of spectrum analysis in each period, it was observed that there existed spectrum features of a consonant and a vowel in the initial and medial periods respectively and features of both in a final sound. Also, when all kinds of words were adaptively divided into 3 periods by using the proposed method, it was found that the initial sounds of the same consonant and the medial sounds of the same vowels have the same spectrum characteristics respectively, but the final sound showed different spectrum characteristics even if it had the same consonant as the initial sound.

• 대한임상검사과학회지
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• 제42권3호
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• pp.111-115
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• 2010

A 15-year-old female with primary amenorrhea and Tuner's syndrome feature was referred for a chromosome analysis. The karyotype of the patient was 45,X/46,X,der(Y) mosaicism under initial GTG-banding analysis. Fluorescence in situ hybridization (FISH) analysis with probe for CEP X probes and SRY probe (Vysis, Inc. Downers Grove, IL 60515, USA) was carried out. This probe is direct labeled with SpectrumOrange (SRY, Yp11.3) and is available as a single probe or mixed with the CEP X SpectrumGreen probe. SRY SpectrumOrange/CEP X SpectrumGreen hybridized to a specimen obtained from an two isodicentric Y chromosomes. The karyotype of the patient was ish Xcen(DXZ1x1)/Xcen(DXZ1x1), Yp11.3(SRYx2) by using FISH. This karyotype was considered a variant of Tuner syndrome with mixed gonadal dysgenesis (MGD), male pseudohermaphroitism (MPH) and apparently normal male.

• Clinical and Experimental Pediatrics
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• 제64권6호
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• pp.286-292
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• 2021

Background: The effect of exposure to environmental factors on autism spectrum disorders (ASD), especially during pregnancy, is unclear. Purpose: This meta-analysis investigated the association between exposure to pesticides and polychlorinated biphenyls (PCBs) during pregnancy and ASD risk among children. Methods: We searched Scopus, PubMed, Web of Science, and ProQuest for articles published through September 2019. Random-effects models were used to examine the association among studies using pooled odds ratios (ORs) and their 95% confidence intervals (CI). I2 tests were used to measure interstudy heterogeneity. Results: The pooled OR indicated a significant association between PCB and pesticide exposure during pregnancy and ASD risk among children (OR, 1.80; 95% CI, 1.26-2.34; and OR, 1.20; 95% CI, 1.02-1.39), respectively. Conclusion: Findings of the present study indicate that exposure to pesticides and PCBs during pregnancy may affect the risk of ASD among children.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.4102-4102
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• 2001

In multivariate analysis, absorbance spectrum is measured over a band of wavelengths. One does not often pay attention to the size of this wavelength band. However, it is desirable that spectrum is measured at only necessary wavelengths as long as the acceptable accuracy of prediction can be met. In this paper, the method of selecting an optimal band of wavelengths based on the loading vector analysis was proposed and applied for determining total protein in human serum using near-infrared transmission spectroscopy and PLSR. Loading vectors in the full spectrum PLSR were used as reference in selecting wavelengths, but only the first loading vector was used since it explains the spectrum best. Absorbance spectra of sera from 97 outpatients were measured at 1530∼1850 nm with an interval of 2 nm. Total protein concentrations of sera were ranged from 5.1 to 7.7 g/㎗. Spectra were measured by Cary 5E spectrophotometer (Varian, Australia). Serum in the 5 mm-pathlength cuvette was put in the sample beam and air in the reference beam. Full spectrum PLSR was applied to determine total protein from sera. Next, the wavelength region of 1672∼1754 nm was selected based on the first loading vector analysis. Standard Error of Cross Validation (SECV) of full spectrum (1530∼l850 nm) PLSR and selected wavelength PLSR (1672∼1754 nm) was respectively 0.28 and 0.27 g/㎗. The prediction accuracy between the two bands was equal. Wavelength selection based on loading vector in PLSR seemed to be simple and robust in comparison to other methods based on correlation plot, regression vector and genetic algorithm. As a reference of wavelength selection for PLSR, the loading vector has the advantage over the correlation plot since the former is based on multivariate model whereas the latter, on univariate model. Wavelength selection by the first loading vector analysis requires shorter computation time than that by genetic algorithm and needs not smoothing.