• 제목/요약/키워드: frequency sharing criteria

검색결과 24건 처리시간 0.027초

Investigation of ITU Radio Regulations Regarding KPS Service Band

  • Subin Lee;Kahee Han;Jong-Hoon Won
    • Journal of Positioning, Navigation, and Timing
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    • 제12권2호
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    • pp.177-184
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    • 2023
  • In order to reserve frequency bands for stable operation of the Korean Positioning System (KPS), it must be demonstrated that the impact of interference caused by KPS on other services operating in the same bands is tolerable. The International Telecommunication Union (ITU) provides the radio regulations and a compatibility assessment methodology for the coexistence of different services in limited frequency resources. The purpose of this paper is to investigate the radio regulations regarding the compatibility issues between the KPS and other services sharing the same frequency bands. The results of the investigation show that the RNSS system can be operated in the L5-band under the condition that the Power Flux Density (PFD) and Aggregated Equivalent PFD (AEPFD) thresholds specified in the radio regulations are met. In addition, the ITU recommends that the interference-to-noise ratio (INR) protection criteria be met to prevent degradation of the performance of radar systems operating in the L2/L6-band. In the case of the S-band, coordination of allocations for RDSS space stations with respect to terrestrial services is not required if the PFD does not exceed regulated thresholds regulated by ITU.

주파수 공유를 위한 HAPS 시스템이 무선 중계국에 미치는 간섭 영향 분석 (Interference Analysis of Radio-Relay Stations Affected by HAPS System for Frequency Sharing)

  • 박종민;구본준;안도섭;김봉석;강영흥
    • 한국통신학회논문지
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    • 제27권7B호
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    • pp.719-726
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    • 2002
  • WRC-2000에서 3GHz 이상의 대역에서 운영할 성층권 통신 시스템(HAPS)의 이용에 관한 연구로 Resolution 734가 채택되었다. 이에 새로운 HAPS 시스템과 기존의 지구상의 고정 서비스간의 공유 가능성이 먼저 분석되어야 한다. 본 논문에서는 HAPS 시스템이 무선 중계국에 미치는 간섭 영향을 두 가지의 경우로 나누어서 분석한다. 한가지는 HAPS 비행선의 PFD(Power Flux Density)에 의한 간섭이며, 다른 한가지는 HAPS의 지구국으로부터의 간섭영향이다. 분석 결과 위성 시스템과는 다른 새로운 PFD 기준 설정이 필요하며, 기존의 FS 시스템과 새로운 HAPS 시스템의 공유를 위한 HAPS nadir 사이의 조정거리는 전송전력밀도가 -50dBW/MHz 일 때 최고 253km에서 최저 60km정도가 요구된다.

NGSO/MSS시스템과 M/W 무선국간의 주파수 공유를 위한 간섭 분석 (A Study on the Interference for Sharing between the NGSO/MSS System and the M/W Station)

  • 이성수;이형수;채종석;강영흥
    • 한국전자파학회논문지
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    • 제10권2호
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    • pp.196-206
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    • 1999
  • 본 연구에서는 NGSO/MSS 시스템이 기존에 이미 운용되고 있는 고정서비스 M/W 시스템의 대역내에 주파수공유를 위한 가능성 및 두 시스템간의 간섭 영향에 대해 평가를 행하였다. 두 시스템간에 일어날 수 있는 간섭의 경우로서, 이동위성의 PFD 레벨에 의한 평가, 피이더 링크상의 간섭분석으로서 C/I 레벨 평가 및 조정영역 분석을 통한 주파수공유를 평가하였다. 또한, 서비스 링크상의 간섭분석으로서 M/W 시스템이 NGSO/MSS 핸드셋에 미치는 간섭의 경우와 이의 반대의 경우, 각 경우에 있어서의 간섭분석 모델설정 및 관련 수식을 유도하여 각 시스템 성능을 평가하는 동시에 간섭 조정영역에 의한 주파수공유 기준을 도출하였다. 도출된 결과들은 향후 NGSO/MSS 시스템과 고정 M/W 무선국간의 주파수 공유를 위한 기준 설정에 중 요 데이터로서 활용될 것이다.

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비정지궤도 위성시스템 및 정지궤도 위성시스템과의 등가전력속밀도 연속곡선 분석 (Analysis of continuous curves of EPFDs between non-GSO/FSS and GSO/FSS)

  • 장재철;양규식;정종혁
    • 한국정보통신학회논문지
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    • 제5권1호
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    • pp.34-40
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    • 2001
  • WRC-2000에서 지상망과 정지궤도(GSO)를 이용한 위성통신 및 방송으로 분배된 Ku(14/11GHz) 및 Ka(30/20GHz)대역의 일부를 비정지궤도(non-GSO) 위성시스템과 공유하여 사용키로 결정함에 따라, 비정지궤도 위성시스템과 기존 정지궤도 위성망간 주파수대역의 공유문제, 간섭기준 및 간섭영향 평가 등에 관한 연구의 필요성이 제기되어 본 논문에서는 우리나라 위성망의 등가전력속밀도를 계산하기 위해 네 가지 분석방법을 사용하였다.

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A New Methodology for Estimating the Impact of Co-Channel Interference from High-Altitude Platforms to Terrestrial Systems

  • Milas Vasilis F.;Constantinou Philip
    • Journal of Communications and Networks
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    • 제8권2호
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    • pp.175-181
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    • 2006
  • This paper addresses an in-depth analysis of the stratosphere-to-Earth co-channel interference produced by high-altitude platforms (HAPs) and proposes a new methodology for the evaluation of its impact to terrestrial systems in terms of fractional degradation in performance, taking into account parameters such as HAP's mobility, realistic distribution of azimuth and elevation angles of the terrestrial microwave links (TMLs), and gradual high-altitude platform network (HAPN) loading. Simulations performed for different HAPN configurations, prove that the implementation of the methodology proposed, may lead to a more efficient use of the spectrum shared between the two services.

APACHE Ⅲ를 이용한 중환자 분류도구의 타당도 검증 (Patient Severity Classification in a Medical ICU using APACHE Ⅲ and Patient Severity Classification Tool)

  • 이경옥;신현주;박현애;정현명;이미혜;최은하;이정미;김유자;심윤경;박귀주
    • 대한간호학회지
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    • 제30권5호
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    • pp.1243-1253
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    • 2000
  • The purpose of this study was to verify the validity of the Patient Severity Classification Tool by examining the correlations between the APACHE Ⅲ and the Patient Severity Classification Tool and to propose admission criteria to the ICU. The instruments used for this study were the APACHE Ⅲ developed by Knaus and the Patient Severity Classification Tool developed by Korean Clinical Nurses Association. Data was collected from the 156 Medical ICU patients during their first 24 hours of admission at the Seoul National University Hospital by three trained Medical ICU nurses from April 20 to August 31 1999. Data were analyzed using the frequency, $x^2$, Wilcoxon rank sum test, and Spearman rho. There was statistically significant correlations between the scores of the APACHE III and the Patient Severity Classification Tool. Mortality rate was increased as patients classification of severity in both the APACHE III and the Patient Severity Classification Tool scored higher. The Patient Severity Classification Tool was proved to be a valid and reliable tool, and a useful tool as one of the severity predicting factors, ICU admission criteria, information sharing between ICUs, quality evaluations of ICUs, and ICU nurse staffing.

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당뇨병전기 성인의 신체운동과 류마티스 발생률 (Physical Activity and Prevalence of Rheumatoid Arthritis in Korean Adults with Prediabetes in the 2009-2013 National Health Cohort Study)

  • 신혜연
    • 한국임상약학회지
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    • 제29권4호
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    • pp.278-285
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    • 2019
  • Background: Rheumatoid arthritis is highly prevalent in overweight patients with type 2 diabetes mellitus and can be reduced by physical activity via altered proinflammatory parameters. However, the association between the frequency of physical activity and the prevalence of rheumatoid arthritis in prediabetic patients remains unclear and was evaluated in this study. Methods: Utilizing the Korean National Health Insurance Sharing Service database, 58,391 adults, who met the research criteria and underwent a general medical check-up between 2009 and 2013, were selected for this study. To analyze the data, a logistic regression with a proc survey logistic procedure was used. Results: The study revealed that the cumulative rheumatoid arthritis prevalence was lower in prediabetic patients compared to that in the control group (OR, 0.64; 95% CI, 0.483-0.840; p=0.001). More frequent physical activity (≥3 days/week) was significantly associated with a reduced rheumatoid arthritis prevalence in both groups (OR, 0.28; 95% CI, 0.039-0.521; p=0.044 vs. OR, 0.15; 95% CI, 0.063-0.237; p=0.007). Additionally, a 3.8-fold higher risk of rheumatoid arthritis development was observed in prediabetic adults with less frequent baseline physical activity (≤2 days/week). Overall, in prediabetes, the prevalence of rheumatoid arthritis was associated with the frequency of physical activity and not with the fasting plasma glucose levels. Conclusion: More frequent physical activity is associated with a low risk of developing rheumatoid arthritis in prediabetic patients. Thus, further studies are needed to confirm the clinical outcomes of frequent physical activity in rheumatoid arthritis prevention and control.

Korean Customer Attitudes Towards SNS Shopping

  • Cho, Young-Sang;Heo, Jeong-Yoon;Youn, Myoung-Kil
    • 유통과학연구
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    • 제10권8호
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    • pp.7-14
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    • 2012
  • As a new format of retailing, social shopping on SNS has rapidly grown in recent. Although there is much literature associated with customer behaviours in the academic world, little attention has been paid to identifying the shopping patterns of SNS shoppers. This paper will, thus, identify how perceived value has an impact on the buying intention of SNS shoppers, after illustrating what kind of factor influences the formation process of perceived value in the Korean marketplace. Given that SNS shoppers are for the most part 20s as well as 30s, the authors handed out questionnaires to them. Furthermore, based on literature review results, the conceptualised research model was developed. Despite lack of literature, the authors developed five constructs like price reduction, quantity- and time-limited message, product ranges, information-sharing, and required number of shoppers. The researchers made a considerable effort to identify the relationship between research concepts and each variable, based on a few research analysis methods such as frequency analysis, the Varimax rotation technique used orthogonal rotation, Cronbach's Alpha, PCA (Principle Component Analysis), and the like. Amongst the 5 variables used to measure the degree of influences on the perceived value as a social shopping characteristic, it has been evident that price cut, required minimum shoppers, product variety, and information-sharing have a positive impact on the perceived value formation processes of SNS customers. Also, this research implies that SNS retailers can differentiate themselves from other retailers by differently using the above factors. From a practitioner's point of view, these factors should be strategically used to increase the social shopping opportunities of SNS users. It is, furthermore, evident that the perceived value formed by the above 4 factors have played an important role in the buying decision process of SNS customers. In a sense, whether customers are aware of higher price cut rates, information-sharing, required minimum shoppers, and product variety has a positive impact on making buying decisions. From a retailer's point of view, online shopping mall operators are able to use blog as well as twitter to improve the buying intention as a marketing tool of social network, because the business activities provided by social shopping retailers, like the rapid, accurate responses to customer requirements, the provision of a variety of information, and the communications between customers are closely related to buying intentions. There are a few research limitations to conduct this empirical research. It was not easy to review prior papers, due to its lack. In spite of the increasing number of SNS shoppers in Korea, little research attention has been paid to this kind of research topic by academicians, because buying products or services through SNS is in its infancy. With regard to research populations, it would be difficult to generalise the research findings in Korea, owing to unbalanced respondent distribution. Considering the above research limitations as well as the growth of social shopping, many authors should pay considerable attention to SNS-related issues in the future, and develop the more sophisticated criteria to measure the characteristics of SNS shoppers.

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패션제품 대여 서비스 이용자의 구매의사결정과정과 의복 쇼핑성향에 관한 탐색적 연구 (An Exploratory Study on Purchase Decision Making Process and Clothing Shopping Orientation of Fashion Products Rental Service Users)

  • 이지윤;신은정;고애란
    • Human Ecology Research
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    • 제56권6호
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    • pp.555-571
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    • 2018
  • This study identified the characteristics of fashion rental service users as well as analyzed their purchase decision-making processes. A qualitative investigation was conducted through in-depth interviews with 13 women in their 20s-30s who have experienced renting fashion items due to a high interest in fashion. The results of the study are summarized as follows. The need recognition stage analyzed ventilation by mass media, SNS impact, curiosity, saving shopping time and money, awareness of situational necessity, and creation of various styles. The information search stage analyzed how users obtained information from 2 different sources of nonmarketer-dominated sources and marketer-dominated sources. The pre-purchase stage analyzed the evaluation of alternatives in which study participants used 2 evaluation criteria for fashion rental services and fashion rental items. The purchase stage analyzed how participants wait and select desired items (when receiving the notification of rentable items) or select alternative products. The consumption stage examined the usage frequency and usage method. The study divided the post-consumption evaluation stage into 2 categories for evaluation: personal feelings and service. The post-consumption behavior stage analyzed how participants displayed WOM, eWOM and purchase rental product behavior. Clothing shopping orientation of study participants is displayed in 5 dimensions of brand-seeking propensity, individuality-seeking propensity, economic efficiency-seeking propensity, rationality-seeking propensity, and pleasure-seeking propensity. This study identified three main characteristics in the study participants: interest in the fashion, favorable attitude toward used fashion items, consciousness of others.

매선요법의 류마티스 관절염 동물모델을 활용한 실험연구: 체계적 문헌고찰 (Thread Embedding Therapy in Rheumatoid Arthritis: A Systematic Review of Animal Studies)

  • 전푸르메;조혜연;강석윤;한창현
    • Korean Journal of Acupuncture
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    • 제38권3호
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    • pp.122-132
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    • 2021
  • Objectives : This systematic review aims to assess the effectiveness of thread embedding therapy on animal model for rheumatoid arthritis. Methods : Search was conducted in the Cochrane library, MEDLINE (PubMed), EMBASE, the Chinese National Knowledge Infrastructure, Wan-Fang Database, Technology Journal Database, the Korean Studies Information Service System, the Oriental Medicine Advanced Searching Integrated System, the Research Information Sharing Service, the National Digital Science Library, the Korean Traditional Knowledge Portal and the Korea Citation Index. Data were extracted concerning animal model, intervention and rheumatoid arthritis indicator by two independent reviewers. Reporting quality was also evaluated by the ARRIVE (Animal Research: Reporting In Vivo Experiments) guidelines 2.0. Results : One thousand thirty six studies were primarily selected. After screening, 10 studies met the inclusion criteria. 1 study was published 2005, 1 study was published 2010, 1 study was published 2012, 1 study was published 2015, 2 studies were published 2016, 3 studies were published 2017, 1 study was published 2018. The most frequently used acupoints were ST36 and BL23, and were used with an average frequency of 11.8 days. All of these thread embedding therapy studies were effective on behavioral, morphological, immunohistological and hematological indicators to treat of rheumatoid arthritis model. Conclusions : These results demonstrated the effectiveness of thread embedding therapy and suggested the putative mechanism. However, considering the small number of included studies, low reporting quality and differences in study design, further studies with rigorous designs and high reporting quality need to be conducted.