• Title/Summary/Keyword: spectrum management

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Post-earthquake warning for Vrancea seismic source based on code spectral acceleration exceedance

  • Balan, Stefan F.;Tiganescu, Alexandru;Apostol, Bogdan F.;Danet, Anton
    • Earthquakes and Structures
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    • v.17 no.4
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    • pp.365-372
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    • 2019
  • Post-earthquake crisis management is a key capability for a country to be able to recover after a major seismic event. Instrumental seismic data transmitted and processed in a very short time can contribute to better management of the emergency and can give insights on the earthquake's impact on a specific area. Romania is a country with a high seismic hazard, mostly due to the Vrancea intermediate-depth earthquakes. The elastic acceleration response spectrum of a seismic motion provides important information on the level of maximum acceleration the buildings were subjected to. Based on new data analysis and knowledge advancements, the acceleration elastic response spectrum for horizontal ground components recommended by the Romanian seismic codes has been evolving over the last six decades. This study aims to propose a framework for post-earthquake warning based on code spectrum exceedances. A comprehensive background analysis was undertaken using strong motion data from previous earthquakes corroborated with observational damage, to prove the method's applicability. Moreover, a case-study for two densely populated Romanian cities (Focsani and Bucharest) is presented, using data from a $5.5M_W$ earthquake (October 28, 2018) and considering the evolution of the three generations of code-based spectral levels for the two cities. Data recorded in free-field and in buildings were analyzed and has confirmed that no structural damage occurred within the two cities. For future strong seismic events, this tool can provide useful information on the effect of the earthquake on structures in the most exposed areas.

Mealtime Behavior and Food Preferences of Children with Autism Spectrum Disorder and Nutrition Education Needs Perceived by Special Education Teachers (특수교사가 인식하는 자폐범주성장애 아동의 식행동 및 식품기호도와 영양교육 요구도)

  • Choi, Su Jin;Oh, Ji Eun;Kim, Yu-Ri;Kim, Yuri
    • Journal of the Korean Society of Food Culture
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    • v.36 no.1
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    • pp.40-55
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    • 2021
  • The purpose of this study was to provide basic information on the development of nutrition education programs to improve the mealtime behavior of children with autism spectrum disorder (ASD) by investigating the mealtime behavior and food preferences of children with ASD through the perception of special education teachers. Surveys were given to 108 special education teachers in special education schools in Korea regarding the demographic characteristics, nutrition education support needs, mealtime behavior, and food preferences of children with ASD. Most of the special education teachers responded that nutrition education in special schools had not been conducted properly and nutrition education for ASD children is necessary. Mealtime behavior analysis classified the behavior into three clusters: cluster 1, 'less problematic mealtime behavior'; cluster 2, 'general feature of autism'; cluster 3, 'difficulty in self-directed diet'. The age, eating habits, and food preferences were different according to each mealtime behavior cluster. Therefore, it will be necessary to develop a nutrition education program based on the characteristics of mealtime behavior.

Statistical Considerations of Oral Health Conditions and Dental Management of Autism Spectrum Disease and Cerebral Palsy Patients (자폐 스펙트럼 질환 환자, 뇌성마비 환자의 구강 상태 및 치과 치료에 관한 통계적 고찰)

  • Jung, Ji Hyun;Park, Jae Hong;Kim, Kwang Chul;Choi, Yeong Chul;Choi, Sung Chul
    • Journal of The Korean Dental Society of Anesthesiology
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    • v.12 no.3
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    • pp.165-171
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    • 2012
  • Background: The aim of this study was to investigate and compare the oral health conditions of Autism Spectrum Disease (ASD) and cerebral palsy(CP) patients visiting the Kyung Hee University Dental Hospital from January 2003 to december 2010. Methods: This study analyzed the data (patient's chart and radiograph) of fifty-eight ASD patients and fifty-seven CP patients. The oral health conditions of patients were surveyed by DMFT (dmft) and periodontal condition at the first visit. The performed dental procedure, behavior management methods and follow-up check were analyzed. Results: The average age of patients having ASD and CP was 12 year 2 month (ASD; 11 year 9 month and CP; 12 year 4 month). Within the limit of this study, the rate of dental caries was higher in CP patients than autism patients. Both of diseases showed the periodontal problem. Autistic patients showed more difficult management problems according to the rate of general anesthesia experiences. Conclusions: This article would contribute for dental practitioners to provide appropriate and specialized treatment to ASD patients and CP patients.

Dietary Behavior and Food Preferences according to Age and the Parents' Nutrition Education Needs of Children with Autism Spectrum Disorder (자폐범주성장애 아동의 나이에 따른 식행동 및 식품 기호도와 학부모의 영양교육 요구도)

  • Park, Hae Jin;Choi, Su Jin;Kim, Yuri;Park, Jiyeon;Kim, Yu-Ri;Lee, Suk-Hyang;Jung, Seo Jin;Cho, Mi Sook;Oh, Ji Eun
    • Journal of the Korean Society of Food Culture
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    • v.35 no.3
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    • pp.241-255
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    • 2020
  • This study examined the eating habits and preferences of foods according to the age of children with autism spectrum disorders and identified the nutritional needs of parents to support their healthy eating habits and provide basic data for the development of educational programs. A survey of 100 parents of children with autism spectrum disorders was conducted on their children's snack intake, food preferences, and parents' nutrition education needs. As a result, there were four times more boys than girls, and the body mass index differed according to age (p<0.001). Most children ate snacks more than once a day, and parents found that they wanted to develop nutritious snacks that could replace high-protein, low-calorie meals with the minimal use of additives. For the food preference, there was a significant difference in grains and starches, vegetables/seafood and fruits, milk and dairy products (p<0.05), fats and sugars, and Korean fermented pastes (p<0.01) between the two age groups. Regarding whether nutrition education was required, many parents had a high demand for nutrition education (4.24±0.70), and the intention to participate was 3.62±1.09. The most important content to be dealt with in parent education was 'Inducing a change in bad eating habits and behaviors', which was the highest (63%), and mostly face-to-face education was preferred. In conclusion, young children require diet education, and older children need to focus on weight control and obesity.

An Efficient Admission Control Algorithm to Keep Connections of Secondary Users in Cognitive Radio Systems (인지 무선 시스템에서 이차 사용자의 다자 수용 및 연결 유지를 위한 효율적인 알고리즘에 대한 연구)

  • Ha, Seong-Cheol;Kim, Se-Heon
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2007.11a
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    • pp.464-468
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    • 2007
  • In cognitive radio systems, secondary users, unlicensed users, can use primary users' spectrum to increase spectrum efficiency. At that time, the systems must satisfy primary users' QoS. When secondary users use cognitive radio systems, secondary users communication can be terminated, because of satisfying primary users' QoS. However, secondary users' communication terminating is not good for both secondary users and whole systems. So, cognitive radio systems need an efficient algorithm for secondary users of admission control and keeping connections. In this paper, we present an algorithm which consist of two part, admission control and connections control.

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A Study On Adaptive Correlator Receiver with Narrow-band Interferance in CDMA System (CDMA System에서 협대역 간섭제거 적응 상관기에 관한 연구)

  • Jeong Chan-Ju;Yang Hwa-Sup;Kim Yong-Shik;Oh Seung-Jae;Kim Jae-Gab
    • Management & Information Systems Review
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    • v.3
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    • pp.201-214
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    • 1999
  • Adaptive correlator receiver with neural network based on complex multilayer perceptron is persented for suppressing interference of narrow-band of direct spread spectrum communication systems. Recursive least square algorithm with backpropagation error is used for fast convergence and better performance in adaptive correlator scheme. According to signal noise and transmission power, computer simulation results show that bit error ratio of adaptive correlator using neural network improved that of adative transversal filter of direct sequence spread spectrum considering of jamming and narrow-band interference. Bit error ratio of adaptive correlator with neural network is reduced about 10-1 than that of adaptive transversal filter where interference versus signal ratio is 5dB.

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Simulation of Terahertz Signal Generation by Dispersion-dependent Kelly Sidebands of Mode-locking Fiber Lasers

  • Weiqian Zhao;Mingya Shen;Youyou Hu;Ziye Wang
    • Current Optics and Photonics
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    • v.7 no.4
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    • pp.443-448
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    • 2023
  • The ±1-order Kelly sidebands with dispersion-dependent spacing of mode-locking fiber lasers are investigated for frequency-tunable terahertz signal generation. The principle of dispersion dependence of Kelly sidebands is analyzed. A new method, which is a dispersion-management mechanism introduced into the fiber-laser cavity, is proposed to generate Kelly sidebands with widely tunable wavelength spacing. A spacing tuning range of up to 28.46 nm of the ±1-order Kelly sidebands is obtained in simulation. Using the data of the optical spectrum with dispersion-dependent Kelly sidebands, the frequency spectrum of generated terahertz signals is calculated. Consequently, the signal frequency can be changed from 0.09 to 2.27 THz.

Neutron Spectrum Effects on TRU Recycling in Pb-Bi Cooled Fast Reactor Core

  • Kim Yong Nam;Kim Jong Kyung;Park Won Seok
    • Nuclear Engineering and Technology
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    • v.35 no.4
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    • pp.336-346
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    • 2003
  • This study is intended to evaluate the dependency of TRU recycling characteristics on the neutron spectrum shift in a Pb-Bi cooled core. Considering two Pb-Bi cooled cores with the soft and the hard spectrum, respectively, various characteristics of the recycled core are carefully examined and compared with each other. Assuming very simplified fuel cycle management with the homogeneous and single region fuel loading, the burnup calculations are performed until the recycled core reached to the (quasi-) equilibrium state. The mechanism of TRU recycling toward the equilibrium is analyzed in terms of burnup reactivity and the isotopic compositions of TRU fuel. In the comparative analyses, the difference in the recycling behavior between the two cores is clarified. In addition, the basic safety characteristics of the recycled core are also discussed in terms of the Doppler coefficient, the coolant loss reactivity coefficient, and the effective delayed neutron fraction.

Valuation on Economical Value of Operation Frequencies for the Fishery Communications (어업통신을 위한 운용주파수의 경제적 가치 평가)

  • Choi, Jo-Cheon;Kim, Geon-Ung;Kim, Jeong-Nyun;Lee, Seong-Ro
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39C no.9
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    • pp.774-781
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    • 2014
  • Demand for spectrum resources is increasing with the development of mobile telecommunications and so is their economic value. As a way to enhance the economic efficiency of use of spectrum resources, many countries have focused on the management of public and broadcasting spectrums which have traditionally been undercharged compared to their economic values. In this paper, we discuss the economic value valuation of the frequencies for the fisheries communications. The estimated value is the average value of the total equipment cost of the mobile communication services that their service coverage is nation-wide, and the value that adjusted the auction price for the LTE service frequencies in 2011 to the characteristics of fisheries communications.

An Approach for Establishing Conceptual Framework of Management Spectirum on the Baekdudaegan Area, Korean (백두대간의 개념적 관리범위모형 수립을 위한 접근)

  • 유기준
    • Korean Journal of Environment and Ecology
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    • v.15 no.4
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    • pp.408-419
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    • 2002
  • The purpose of this study was to establish a conceptual management spectrum framework for integrated management of Baekdudaegan area. The conceptual model was developed through a literature survey that includes the concepts from existing relevant systems and other expert sources In conceptual Baekdudaegan management spectrum framework presented here, three different classes (preservation, buffer, and multiple-use) that specify potential management objectives for area functions were classified in order to pursue management flexibility Three primary management classes should be identified by evaluating Indicators of ecological, physical, and social.cultural environments. An application of the framework requires an explicit selection of indicators and their evaluation. For establishing reliability of the framework, it will be desirable to test it empirically in Baedudaegan areas in the future. In addition, systematic case study for selecting appropriate indicators and identifying evaluation standards must be done.