• Title/Summary/Keyword: frequency sharing criteria

Search Result 24, Processing Time 0.02 seconds

Investigation of ITU Radio Regulations Regarding KPS Service Band

  • Subin Lee;Kahee Han;Jong-Hoon Won
    • Journal of Positioning, Navigation, and Timing
    • /
    • v.12 no.2
    • /
    • pp.177-184
    • /
    • 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.

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

  • 박종민;구본준;안도섭;김봉석;강영흥
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.27 no.7B
    • /
    • pp.719-726
    • /
    • 2002
  • In WRC-2000, Resolution 734 was adopted to study the use of high altitude platform station(HAPS) operating in the bands above 30GHz. Therefore, frequency sharing feasibility between a new HAPS systems and an existing terrestrial fixed-service(FS) system should be analyzed primarily. In this paper, interference effects from the HAPS system into the radio-relay station are analyzed in terms of two cases; one is the interference distribution from the power-flux density(PFD) of HAPS airships, and the other the interference power from the ground stations. In conclusion, the new PFD criteria different from the exiting satellite system should be required, and the coordinated distance between the HAPS nadir and the radio-relay station should be 60km ∼ 253km for P$\sub$HG/ = -50dBW/MHz of transmitting power spectral density to share the new HAPS system into the existing FS system.

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

  • 이성수;이형수;채종석;강영흥
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.10 no.2
    • /
    • pp.196-206
    • /
    • 1999
  • In this paper, we have estimated the interference effects between the NGSO/MSS system and the fixed-service M/W system for sharing the NGSO/MSS system into the frequency band operated by the existing M/W system. Between above two systems, the interference effects must be analyzed in the following three points. That is, PFD(Power Flux Density) level must be obtained in the case of the interference from NGSO satellites into M/W stations, C/I(Carrier-to-Interference Ratio) and the coordination contour in the case of the interference between NGSO/MSS feeder link and a M/W station, and the interference power level and coordination contour in the case of the interference between NGSO/MSS service link(handsets) and M/W stations. Therefore, in order to obtain above three criteria, we have developed the analytical model, introduced the related equations and estimated the system performance by means of the simulation and the theoretial analysis. It is expected that the results will be utilized in setting the criterion for sharing between the NGSO/MSS system and the M/W station.

  • PDF

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

  • 장재철;양규식;정종혁
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.5 no.1
    • /
    • pp.34-40
    • /
    • 2001
  • The necessary of research is proposed about sharing between networks of the fixed-satellite service using non-geostationary satellites and other networks of the fixed-satellite service, interference criteria and calculation methods for the fixed-satellite service because WRC-2000 make a decision that the frequency bands l1/14GHz and 20/30GHz are available to system in the fixed-satellite service employing satellite in both geostationary and non-geostationary orbits. In the paper, four methodologies attempting to derive continuous curves of korea satellite network EPFD(equivalent power flux density) are used.

  • PDF

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
    • /
    • v.8 no.2
    • /
    • pp.175-181
    • /
    • 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.

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

  • Lee, Gyeong-Ok;Sin, Hyeon-Ju;Park, Hyeon-Ae;Jeong, Hyeon-Myeong;Lee, Mi-Hye;Choe, Eun-Ha;Lee, Jeong-Mi;Kim, Yu-Ja;Sim, Yun-Gyeong;Park, Gwi-Ju
    • Journal of Korean Academy of Nursing
    • /
    • v.30 no.5
    • /
    • pp.1243-1253
    • /
    • 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.

  • PDF

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

  • Sin, Hye Yeon
    • Korean Journal of Clinical Pharmacy
    • /
    • v.29 no.4
    • /
    • pp.278-285
    • /
    • 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
    • Journal of Distribution Science
    • /
    • v.10 no.8
    • /
    • pp.7-14
    • /
    • 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.

  • PDF

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

  • Lee, Ji-Yoon;Shin, Eun-Jung;Koh, Ae-Ran
    • Human Ecology Research
    • /
    • v.56 no.6
    • /
    • pp.555-571
    • /
    • 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.

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

  • Jun, Purumea;Zhao, HuiYan;Kang, Suk-Yun;Han, Chang-Hyun
    • Korean Journal of Acupuncture
    • /
    • v.38 no.3
    • /
    • pp.122-132
    • /
    • 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.