• Title/Summary/Keyword: beyond 5G

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Frequency Sharing of Cellular TDD-OFDMA Systems beyond 3G with Terrestrial Fixed Systems (TDD-OFDMA 기반의 차세대 셀룰라 시스템과 육상 고정 시스템 간의 주파수 공유 분석)

  • Jo, Han-Shin;Yoon, Hyun-Goo;Yook, Jong-Gwan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.1A
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    • pp.125-133
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    • 2007
  • In this paper, the frequency sharing issue between cellular time division duplex-orthogonal frequency division multiple access (TDD-OFDMA) Systems and terrestrial Fixed Systems has been studied. The conventional advanced minimum coupling loss (A-MCL) includes only the formulation to calculate the interference from one interfering system. Therefore, A-MCL must be modified to assess the aggregated interference from base stations(BS) and mobile stations(MS). By applying the modified model, the coexistence analysis are done according to the average number of MS per sector, BS-to-BS distance, and the main beam direction of the terrestrial fixed system. In the case of 20 MS per sector, the BS-to-BS distance and the minimum distance between a terrestrial fixed system and BS are 5.8 km and 2.5 km, respectively. It is about 25dB that the difference between maximum and minimum interference signal power which varies with the main beam direction of the terrestrial fixed system. Moreover, for 40% of the main beam direction of the terrestrial fixed system, interference signal power is less than the maximum permissible interference.

Construction of 21st Century Visual Algorithm in 5G-based VR/AR/MR/Hologram (5G기반 VR/AR/MR/Hologram의 공간에서 나타나는 21세기형 시각 알고리즘 구축)

  • Lim, Sang Guk
    • Journal of Korea Multimedia Society
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    • v.22 no.10
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    • pp.1208-1214
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    • 2019
  • 4th industrial age! 5G-based video content has changed rapidly. How do you view and understand VR/AR/MR/holograms in the age of convergent technology media represented by digital convergence in the 21st century beyond the modern visual system of Descartes? It predicts extension to an interactive visual system. This study proposes a methodology to visualize the Lacanian visual acuity after applying it to the L-System and to understand the visual system of the 21st century.

Evaluation of VoIP Capacity for IEEE802.11b WiFi Environment under Voice Coding Methods (IEEE802.11b WiFi 환경에서 음성코딩 방식에 따른 VoIP 용량분석)

  • Choi, Dae-Woo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.7 no.2
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    • pp.243-248
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    • 2012
  • In this paper we simulate the capacity of VOIP calls through WiFi network by computer simulations using OPNET modeler. The results show that sudden quality degradations occur on all VoIP calls when the number of call of an AP(Access Point) increases beyond a specific value. The reason of the quality degradation was turned out to be the queueing delay at the down link of AP. Under the IEEE 802.11b environments, the maximum number of VoIP calls of an AP maintaining the required voice quality (MOS > 2.5), was evaluated as 5, 12, and 27 when we use G.711, G.729a, and G.729a VAD codec, respectively.

Introducing Software Defined Radio to 4GWireless: Necessity, Advantage, and Impediment

  • Zamat, Hassan;Nassar, Carl R.
    • Journal of Communications and Networks
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    • v.4 no.4
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    • pp.344-350
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    • 2002
  • This work summarizes the current state of the art in software radio for 4G systems. Specifically, this work demonstrates that classic radio structures, e.g., heterodyne reception, homodyne reception, and their improved implementations, are inadequate selections for multi-mode reception. This opens the door to software defined radio, a novel reception architecture which promises ease in multi-band, multi-protocol design. The work presents the many advantages of such an architecture, including flexibility, reduced cost via component reduction, and improved reliability via, e.g., the elimination of environmental instability. The work also explains the limitations that currently curtail the widespread use of SDR, including issues surrounding A/D converters, management of software and power, and clock generation. This provides direction for future research to enable the broad applicability of SDR in 4G cellular and beyond.

Effect of nitric Oxide Compounds on the Development of Porcine IVM/IVF Embryos (Nitric Oxide 화합물 첨가가 돼지 체외수정란의 체외발육에 미치는 효과)

  • 박기은;박춘근;김정익;정희태;박동헌;양부근
    • Korean Journal of Animal Reproduction
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    • v.25 no.1
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    • pp.63-69
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    • 2001
  • This study was carried out to examine the effects of nitric oxide compounds (hemoglobin and L-NAME) on the development of porcine in vitro maturation (IVM) and in vitro fertilization (IVF) oocytes. Cumulus cell free embryos derived from porcine IVM/IVF oocytes were cultured in NCSU23 medium containing 1~5 $\mu\textrm{g}$/$m\ell$ hemoglobin added to 44 and 96hrs in culture times, and in NCSU23 medium containing 0, 10, 50 or 100mM L-NAME. The developmental rates beyond morulae stage in 0, 1 and 5 $\mu\textrm{g}$/$m\ell$ hemoglobin groups add to 44hrs in vitro culture times were 52.4%, 57.6% and 57.4%, respectively. The addition of hemoglobin groups made it slightly higher than the control group. The proportion of embryos developed to morulae and blastocysts in 1 $\mu\textrm{g}$/$m\ell$ hemoglobin add to 96hrs after in vitro culture (70.8%) was a little higher than those of 0 and 5 $\mu\textrm{g}$/$m\ell$ hemoglobin (66.2% and 62.8%). There was no significant difference in all groups (P〉0.05). The developmental rates beyond morulae stage in 0, 10, 50 and 100mM of L-NAME groups add to 96hrs after in vitro culture were 65.2%, 73.5%, 70.1% and 53.3%, respectively 10mM and 50mM L-NAME groups were significantly higher than in 0 and 100mM of L-NAME groups (P<0.05). In conclusions, these results indicate that L-NAME (10mM, 50mM) can increase the proportion of embryos that develop into morulae and blastocysts but hemoglobin did not affect.

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Evaluation of Seismic Fragility Curve of Seismically Isolated Nuclear Power Plant Structures for Artificial Synthetic Earthquakes Corresponding to Maximum-Minimum Spectrum (최대-최소 스펙트럼에 대응하는 인공합성지진에 대한 면진된 원전구조물의 지진취약도 곡선 평가)

  • Kim, Hyeon-Jeong;Song, Jong-Keol
    • Journal of the Earthquake Engineering Society of Korea
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    • v.23 no.2
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    • pp.89-99
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    • 2019
  • In order to increase the seismic safety of nuclear power plant (NPP) structures, a technique to reduce the seismic load transmitted to the NPP structure by using a seismic isolation device such as a lead-rubber bearing has recently been actively researched. In seismic design of NPP structures, three directional (two horizontal and one vertical directions) artificial synthetic earthquakes (G0 group) corresponding to the standard design spectrum are generally used. In this study, seismic analysis was performed by using three directional artificial synthetic earthquakes (M0 group) corresponding to the maximum-minimum spectrum reflecting uncertainty of incident direction of earthquake load. The design basis earthquake (DBE) and the beyond design basis earthquakes (BDBEs are equal to 150%, 167%, and 200% DBE) of G0 and M0 earthquake groups were respectively generated for 30 sets and used for the seismic analysis. The purpose of this study is to compare seismic responses and seismic fragility curves of seismically isolated NPP structures subjected to DBE and BDBE. From the seismic fragility curves, the probability of failure of the seismic isolation system when the peak ground acceleration (PGA) is 0.5 g is about 5% for the M0 earthquake group and about 3% for the G0 earthquake group.

COMMENTS ON DING'S EXAMPLES OF FC-SPACES AND RELATED MATTERS

  • Park, Se-Hie
    • Communications of the Korean Mathematical Society
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    • v.27 no.1
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    • pp.137-148
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    • 2012
  • Recently Ding [4, 5, 8] gives examples of his FC-spaces which are not L-spaces due to Ben-El-Mechaiekh et al. [1]. We show that they are actually L-spaces. We also clarify that all statements in [5] can be stated in corrected and generalized forms for the class of abstract convex spaces beyond FC-spaces.

Effect of Microbial Control on Alfalfa Sprout Vegetable by Depending on Sanitization Method in Kindergarten Foodservice (유치원 급식으로 이용되는 알팔파 새싹채소의 소독방법에 따른 미생물제어 효과)

  • Woo, Suhee
    • Journal of The Korean Society of Integrative Medicine
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    • v.4 no.4
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    • pp.109-117
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    • 2016
  • Purpose : This study was designed to provide basic data of effective sanitization method of sprout vegetable for microbiological safety. Methods : Sanitization treatments were performed by dipping the sprout into chlorine and vinegar water. Microbial analysis were composed of the total plate count(TPC) and coliform group count(CGC). Result : Among chlorine water sanitization, the microbial reduction was largest in 100ppm chlorine water, and its TPC and coliform group count decreased to 6.01 log CFU/g and 5.06 log CFU/g. The effective dipping time in 100ppm chlorine water treatment was 5.97 log CFU/g and 5.91 log CFU/g for 30min and 60min, in which TPC were below the microbiological safety limits of 6.00 log CFU/g. Coliform group counts were decreased to 5.44, 5.46, 5.42 log CFU/g in the dipping the spouts for 30min, 60min and 90min. As a result of sanitizing alfalfa spout by vinegar water, a microbial counts tended to decrease with increasing concentration and the dipping time. The effective concentration of vinegar water was 2% for TPC(6.00 log CFU/g) and 1% for coliform group count(5.20 log CFU/g). With 1% vinegar water treatment, TPC became below the microbiological safety limits in all samples and in particular, the sample treated for 60min and 90min(4.93, 4.54 log CFU/g). While coliform group counts were decreased to 3.91 log CFU/g in the dipping the sprouts for 90min, those were still beyond the permitted limit. Conclusion : To secure the food safety of food service facilities including kindergarten feeding, it is considered that along with the systematic study of effective disinfection method for microbiological control at the preconditioning level of spout vegetable within the range of secured maleficence to human body, and the study regarding the measures to lower the initial microbiological pollution of spout vegetable.

Wave Propagation Characteristics for Mobile Communications beyond 3G in Microcellular Environments (마이크로셀룰라 환경에서의 차세대 이등 통신을 위한 전파 전파 특성)

  • Jo Han-Shin;Yook Jong-Gwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.5 s.108
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    • pp.430-439
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    • 2006
  • This paper presents the a measured path-loss characteristics for mobile communications beyond 3G in microcellular residential area and street microcell at 3.4, 5.3, and 6.4 GHz band signals. The residential area is divided into two sections, one of which is composed of fifteen-story appartment buildings. The other section comprises four-story houses. The street microcell is classified line-of-sight(LOS) and nonline-of-sight(NLOS) areas. Both residential areas have standard deviations independent of the residential area classification, whereas the path loss exponents in the apartments is higher than those in area for same frequencies. A two-ray model is applied to analyse the path-loss charateristics in LOS areas. In LOS areas, an empirical breakpoint, whose distance is 6 percent shorter than a theorical breakpoint, is founded. Further, a sudden power level drop occurs at a transition point from LOS region to NLOS area. Path loss exponent is found to be significantly higher for non-LOS region than for LOS region. The power level drop due to corner loss and path-loss exponents both increase as the distance between the transmitter and the corner increases.

Near-BER lossless Asymmetric 2PAM non-SIC NOMA with Low-Complexity and Low-Latency under User-Fairness

  • Chung, Kyuhyuk
    • International Journal of Internet, Broadcasting and Communication
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    • v.13 no.2
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    • pp.43-51
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    • 2021
  • As the number of mobile devices has been increasing tremendously, system capacity should be enlarged in future next generation communication, such as the fifth-generation (5G) and beyond 5G (B5G) mobile networks. For such future networks, non-orthogonal multiple access (NOMA) has been considered as promising multiple access technology. In this paper, to reduce both latency and complexity in existing NOMA, we propose non-successive interference cancellation (SIC) NOMA with asymmetric binary pulse amplitude modulation (2PAM), nearly without bit-error rate (BER) loss. First, we derive the closed form of BER expressions for non-SIC NOMA with asymmetric 2PAM, especially under Rayleigh fading channels. Then, it is shown that the BER performance of the stronger channel user who is supposed to perform SIC in conventional NOMA can be nearly achieved by the proposed non-SIC NOMA with asymmetric 2PAM, especially without SIC. Furthermore, we also show that the BER performance of the weaker channel user in conventional NOMA can be more closely achieved by the proposed non-SIC NOMA with asymmetric 2PAM. These BERs are shown to be achieved over the part of the power allocation range, which is consistent with the NOMA principle of user fairness. As a result, the non-SIC NOMA scheme with asymmetric 2PAM could be considered as a promising NOMA scheme toward next generation communication.